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Antioch Dunes National Wildlife Refuge Comprehensive Conservation Plan

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U.S. Fish & Wildlife Service
Antioch Dunes
National Wildlife Refuge
Comprehensive Conservation Plan
Vision Statement
“Our vision is that endangered species management
will be incorporated into the overall management of
the riverine sand dune ecosystem. Using management
actions that mimic natural processes, the Refuge will
support self-sustaining populations of Lange’s,
wallflower, primrose, and other native species.”
“Through high quality interpretive and environmental
education programs, the public will have opportunities
to visit and gain an appreciation for the unique ecosys-tem
of the Refuge and an understanding of endan-gered
species protection and the role of the Refuge
System in recovering endangered species.”
U. S. Fish and Wildlife Service
California/Nevada Refuge Planning Office
2800 Cottage Way, Room W-1916
Sacramento, CA 95825
August 2002
Antioch Dunes National Wildlife Refuge
i
Table of Contents
Acronymns and Definitions ..................................................................................................................................... iii
List of Selected Scientific Names ............................................................................................................................ iv
Chapter 1 - Introduction ........................................................................................................................................... 1
Introduction ................................................................................................................................................. 1
Purpose and Need for the Plan ................................................................................................................. 1
The U.S. Fish and Wildlife Service and the National Wildlife Refuge System ................................ 2
U.S. Fish and Wildlife Service Responsibilities ....................................................................................... 2
The National Wildlife Refuge System ....................................................................................................... 2
Legal and Policy Guidance ........................................................................................................................... 2
The Antioch Dunes National Wildlife Refuge ........................................................................................ 3
Location ......................................................................................................................................................... 3
Land Ownership........................................................................................................................................... 6
Partnerships ................................................................................................................................................. 6
Refuge Setting ............................................................................................................................................. 6
Refuge History ............................................................................................................................................. 7
Refuge Purpose .......................................................................................................................................... 10
Related Projects and Studies in the Area ............................................................................................. 10
U.S. Fish and Wildlife Service .................................................................................................................. 10
The Recovery Plan for the Primrose, Wallflower, and Lange’s ....................................................... 10
Other Agencies ........................................................................................................................................... 11
Brannan Island State Recreation Area .............................................................................................. 11
The Regional Parks Botanic Garden at Tilden Regional Park ........................................................ 11
Montezuma Wetlands ........................................................................................................................... 11
CALFED............................................................................................................................................... 12
Chapter 2 - The Planning Process .......................................................................................................................... 13
The Planning Process ............................................................................................................................... 13
Issues ......................................................................................................................................................... 14
Issues Identified by the Public ................................................................................................................. 14
Issues Identified by Refuge Staff, Panel of Experts, and Other Agencies ......................................... 15
Chapter 3 - Refuge and Resource Description .................................................................................................... 17
Ecoregion Setting ..................................................................................................................................... 17
Geographic and Physical Setting ............................................................................................................ 17
Wilderness ................................................................................................................................................. 18
Management Area Designations ............................................................................................................. 18
Topography ................................................................................................................................................ 18
Geology ....................................................................................................................................................... 18
Soils............................................................................................................................................................. 21
Climate ....................................................................................................................................................... 21
Air Quality ................................................................................................................................................. 21
Contaminants ............................................................................................................................................ 22
Hydrology .................................................................................................................................................. 23
Water Supply ............................................................................................................................................. 23
Vegetation ................................................................................................................................................... 23
Wildlife ....................................................................................................................................................... 26
Fish ............................................................................................................................................................. 26
Invertebrates ............................................................................................................................................ 26
ii
Endangered Species ................................................................................................................................ 27
Lange’s Metalmark Butterfly - Apodemia mormo langei .................................................................... 28
Background ........................................................................................................................................... 28
Population Size and Status ................................................................................................................... 29
Antioch Dunes Evening Primrose, Oenothera deltoides spp. howellii ............................................... 30
Background ........................................................................................................................................... 30
Population Size and Status ................................................................................................................... 32
Contra Costa Wallflower, Erysimum capitatum spp. angustatum ....................................................... 32
Background ........................................................................................................................................... 32
Population Size and Status ................................................................................................................... 34
Public Use ................................................................................................................................................. 34
Easements ................................................................................................................................................. 35
Cultural Resources .................................................................................................................................. 35
Land Use ................................................................................................................................................... 36
Current Management Practices ............................................................................................................. 36
Annual Surveys .......................................................................................................................................... 36
Nonnative Weed Control ............................................................................................................................ 36
Importing Sand .......................................................................................................................................... 39
Revegetation ............................................................................................................................................... 40
Firebreaks .................................................................................................................................................. 40
Chapter 4 - Problems and Opportunities .............................................................................................................. 41
Problems .................................................................................................................................................... 41
Dune Habitat .............................................................................................................................................. 41
Nonnative Weeds ....................................................................................................................................... 42
Disturbance ................................................................................................................................................ 43
Predation ..................................................................................................................................................... 43
Mammals ............................................................................................................................................... 43
Insects .................................................................................................................................................... 43
Problems Relating to Viable Seed Production ....................................................................................... 43
Wildlife ........................................................................................................................................................ 44
Human Disturbance .................................................................................................................................. 44
Wildfires ...................................................................................................................................................... 44
External Factors ........................................................................................................................................ 45
Lack of Information .................................................................................................................................. 45
Opportunities ............................................................................................................................................ 46
Chapter 5 - Refuge Vision, Goals, and Objectives ................................................................................................ 47
Vision Statement ....................................................................................................................................... 47
Management Philosophy .......................................................................................................................... 47
Goals ........................................................................................................................................................... 47
Endangered Species ................................................................................................................................ 48
Ecosystem Protection, Restoration, and Management....................................................................... 53
Public Use ................................................................................................................................................. 60
Chapter 6 - Funding and Personnel ....................................................................................................................... 65
Chapter 7 - Monitoring and Evaluation ................................................................................................................ 67
Chapter 8 - Compliance Requirements ................................................................................................................. 71
References ................................................................................................................................................................ 75
iii
List of Figures
Figure 1. Regional Map .................................................................................................................................... 5
Figure 2. Refuge Map ....................................................................................................................................... 6
Figure 3. Management Areas with Acreages - Stamm Unit ...................................................................... 19
Figure 4. Management Areas with Acreages - Sardis Unit........................................................................ 20
Figure 5. Three Main Habitat Types on the Refuge ................................................................................... 24
Figure 6. Lange’s Metalmark Butterfly Peak Count Survey Results....................................................... 30
Figure 7. Antioch Dunes Evening Primrose Survey Results .................................................................... 33
Figure 8. Contra Costa Wallflower Survey Results ..................................................................................... 34
Figure 9. Stamm Unit Densities..................................................................................................................... 37
Figure 10. Sardis Unit Densities .................................................................................................................... 38
Figure 11. Proposed Management for Antioch Dunes National Wildlife Refuge .................................. 55
List of Tables
Table 1. General Trends for Refuge Endangered Species.......................................................................... 31
Table 2. Estimated Initial Capital Outlay to Implement the CCP ............................................................ 66
Table 3. Estimated Annual Cost to Implement the CCP ............................................................................ 66
Table 4. Monitoring Methods .......................................................................................................................... 68
List of Appendices
Appendix A - Compatibility Determinations
Appendix B - Technical Panel
Appendix C - Environmental Assessment
Appendix D - Response to Comments
Appendix E - Wilderness Review
Appendix F - Plant List
Appendix G - Bird List
Appendix H - Fish List
Appendix I - Insect List
Appendix J - Fire Management Plan
Appendix K - Glossary
Acronyms and Definitions
U.S. Fish and Wildlife Service Service
Antioch Dunes National Wildlife Refuge Refuge
National Wildlife Refuge refuge
Sacramento/San Joaquin River Delta Delta
Antioch Dunes evening primrose primrose
Contra Costa wallflower wallflower
Lange’s metalmark butterfly Lange’s
California Department of Transportation Caltrans
California Department of Parks and Recreation DPR
California Native Plant Society CNPS
Pacific Gas and Electric Company PG&E
University of California UC
Environmental Assessment EA
National Wildlife Refuge System Refuge System
Comprehensive Conservation Plan CCP
Naked-stemmed buckwheat buckwheat
Global positioning system GPS
State Recreation Area SRA
Management Area MA
Bay Area Air Quality Management District BAAQMD
iv
List of Selected Scientific Names
(also see appendices F, G, H and I)
Oenothera deltoides ssp. howellii (e) Antioch Dunes evening primrose
Erysimum capitatum ssp. angustatum (e) Contra Costa wallflower
Apodemia mormo langei (e) Lange’s metalmark butterfly
Eriogonum nudum var. auriculatum naked-stemmed buckwheat
Centaurea solstitialis yellow starthistle
Bromus diandrus ripgut broome
Vicia villosa ssp. varia winter vetch
Vicia sativa ssp. nigra common vetch
Lepidium latifolium pepperweed
Cortaderia sellowiana pampas grass
Arundo donax giant reed
Robinia psuedoacacia black locust
Nerium oleander oleander
Ailanthus altissima tree of heaven
Croton californicus croton
(e) Federally listed endangered species
Comprehensive Conservation Plan 1
Chapter 1 - Introduction
Introduction
The Antioch Dunes National Wildlife Refuge (Refuge) is the first and
only wildlife refuge in the country established to protect endangered
plants and insects. Created in 1980 by
the U.S. Fish and Wildlife Service
(Service), this riverside refuge
provides protection and critical habitat
for three endangered species: Lange’s
metalmark butterfly (Apodemia
mormo langei) (Lange’s), Contra
Costa wallflower (Erysimum
capitatum angustatum) (wallflower),
and Antioch Dunes evening primrose
(Oenothera deltoides howellii)
(primrose). The Refuge, 55 acres of
former dunes, in addition to the
adjacent 12 acres of Pacific Gas and
Electric Company (PG&E) land, is an
isolated patch of what was once a
larger dune system that hosted a
unique assemblage of plants, insects,
and reptiles. A major effort is
currently underway to restore and
improve dune habitat on the Refuge. The Refuge is managed by staff
based in the San Francisco Bay National Wildlife Refuge Complex office
in Fremont, California.
Purpose and Need for the Plan
The Service prepared this Comprehensive Conservation Plan (CCP) to
guide wildlife and other natural resource management, including public
use, on the Refuge for the next 15 years. The CCP is flexible; it will be
revised periodically to ensure that its goals, objectives, implementation
strategies, and timetables are still valid and appropriate. Major
revisions will require public involvement and National Environmental
Policy Act (NEPA) review, if needed. The CCP will:
■ Provide a clear statement of direction for Refuge management for
the next 15 years.
■ Provide a clear vision of the desired future conditions of the Refuge.
■ Provide the public with an understanding of the reasons for
management actions on the Refuge.
■ Ensure that Refuge management reflects the mission, policies, and
goals of the National Wildlife Refuge System (Refuge System).
■ Ensure the compatibility of current and future uses of the Refuge.
Antioch Dunes Evening primrose and Contra Costa wallflower
USFWS Photo
2 Antioch Dunes National Wildife Refuge
Chapter 1
■ Provide long-term continuity of Refuge management.
■ Provide a basis for operation, maintenance, and development
budget requests.
The U.S. Fish and Wildlife Service and the National Wildlife Refuge
System
U.S. Fish and Wildlife Service Responsibilities
The Service is the primary Federal agency responsible for conserving
and enhancing the Nation’s fish and wildlife populations and their
habitats. Although this responsibility is shared with other Federal,
State, Tribal, local, and private entities, the Service has specific
responsibilities for migratory birds, threatened and endangered species,
anadromous fish, and certain marine mammals. The Service has similar
responsibilities for the lands and waters it administers to support the
conservation and enhancement of fish and wildlife.
The National Wildlife Refuge System
The Refuge System is the world’s largest collection of lands specifically
managed for fish and wildlife conservation. Unlike other Federal lands
that are managed under a multiple-use mandate (e.g., lands
administered by the U.S. Bureau of Land Management and the Forest
Service), the Refuge System is managed for the benefit of fish, wildlife,
plants, and their habitats.
The Service manages the 95 million-acre National Wildlife Refuge
System which encompasses nearly 540 national wildlife refuges,
thousands of small wetlands, and other special management areas. The
majority of refuge lands (approximately 77 million acres) are in Alaska.
The remaining acres are spread across the other 49 states and several
island territories.
The mission of the Refuge System is “to administer a national network
of lands and waters for the conservation, management and, where
appropriate, restoration of the fish, wildlife, plant resources, and their
habitats within the United States for the benefit of present and future
generations of Americans” (16 USC 668dd et seq.). The goals of the
Refuge System are to:
■ Preserve, restore, and enhance in their natural ecosystems (when
practicable) all species of animals and plants that are endangered or
threatened with becoming endangered;
■ Perpetuate the migratory bird resource;
■ Preserve a natural diversity and abundance of fauna and flora on
refuge lands; and
■ Provide an understanding and appreciation of fish and wildlife
ecology, the human role in the environment, and provide refuge
visitors with high-quality, safe, wholesome, and enjoyable wildlife-dependent
recreational experiences oriented toward wildlife to the
extent these activities are compatible with the purposes for which
the refuge was established.
Legal and Policy Guidance
National Wildlife Refuges are guided by the mission and goals of the
Refuge System, purposes of the Refuge, Service policy, laws, and inter-national
treaties. Relevant guidance includes the National Wildlife
Comprehensive Conservation Plan 3
Introduction
Refuge System Administration Act of 1966, as amended by the National
Wildlife Refuge System Improvement Act of 1997 (Improvement Act),
the Refuge Recreation Act of 1962, and selected portions of the Code of
Federal Regulations and the Fish and Wildlife Service Manual.
The Refuge Recreation Act of 1962, as amended, authorized the
Secretary of the Interior to administer refuges, hatcheries, and other
conservation areas for recreational use when such uses did not interfere
with the area’s primary purpose.
The National Wildlife Refuge System Administration Act of 1966, as
amended by the Improvement Act, created a mission statement for the
Refuge System; established six priority public uses (hunting, fishing,
wildlife observation and photography, environmental education and
interpretation); emphasized conserving and enhancing the quality and
diversity of fish and wildlife habitat; stressed the importance of
partnerships with Federal and State agencies, Tribes, organizations,
industry, and the general public; mandated public involvement in
decisions concerning the acquisition and management of refuges; and
required, prior to acquisition of new refuge lands, identification of
existing compatible wildlife-dependent uses that would be permitted to
continue on an interim basis pending completion of comprehensive
conservation planning.
The Improvement Act establishes the responsibilities of the Secretary of
the Interior for managing and protecting the Refuge System; requires a
CCP for each refuge by the year 2012; provides guidelines and
directives for the administration and management of all areas in the
Refuge System, including wildlife refuges, areas for the protection and
conservation of fish and wildlife threatened with extinction, wildlife
ranges, game ranges, wildlife management areas, or waterfowl
production areas.
The Improvement Act also establishes a formal process for determining
compatibility of uses. Before any uses, including priority public uses,
are allowed on refuges, Federal law requires that they be formally
determined “compatible.” A compatible use is defined as a use that, in
the sound professional judgement of the refuge manager, will not
materially interfere with or detract from the fulfillment of the refuge
purposes. Sound professional judgement is defined as a finding,
determination, or decision that is consistent with the principles of sound
fish and wildlife management and administration, available science and
resources (funding, personnel, facilities, and other infrastructure), and
applicable laws. The Service strives to provide priority public uses when
compatible. If financial resources are not available to design, operate,
and maintain a priority use, the Refuge manager will take reasonable
steps to obtain outside assistance from the State and other conservation
interests.
The Refuge has completed compatibility determinations for
environmental education, interpretation, wildlife observation and
photography, and research (Appendix A).
The Antioch Dunes National Wildlife Refuge
Location
The Refuge is adjacent to the City of Antioch, Contra Costa County,
California along the south shore of the San Joaquin River in an area that
4 Antioch Dunes National Wildife Refuge
Chapter 1
was once part of an expanse of riverine sand dunes (Figure 1). The
Refuge consists of two disjunct parcels (Figure 2). The westernmost
unit, the 41-acre Stamm Unit, is bordered to the west by Fulton
Shipyard; to the east by the Georgia-Pacific gypsum plant; to the south
by Fulton Shipyard Road, Burlington Northern/Santa Fe Railroad, and a
former sewage treatment plant and transfer facility; and to the north by
the San Joaquin River. The easternmost unit, the 14-acre Sardis Unit, is
bordered to the west and east by PG&E property; to the north by the
San Joaquin River; and to the south by Wilbur Avenue. The Georgia-
Pacific gypsum plant and the Kemwater North American Company
(Kemwater) are adjacent to the PG&E parcels to the west and east,
respectively.
Land Ownership
The approved refuge boundary encompasses 67 acres, 55 of which are
owned by the Service. The other 12 acres, owned by PG&E,
are part of the same remnant dune ecosystem and include
dune and riparian cover types. In the past (1985 to 1995),
through a cooperative agreement with PG&E, the Service has
conducted some management activities on PG&E land. The
Service and PG&E are currently in the process of
renegotiating the cooperative agreement. In the interim,
PG&E has continued to allow biological surveys to be
conducted on their lands.
The approved refuge boundary identifies important and
sensitive resource areas that the Service is looking to protect
for a long period of time. Landowners within a refuge
boundary retain all the rights, privileges, and responsibilities
of private land ownership. After the Service Director
approves a refuge boundary, the Service can make offers to
purchase land, or enter into management agreements with
willing landowners within the approved boundary. Lands do
not become part of the Refuge System unless they are
purchased or are placed under a management agreement with
the individual landowner. The goals, objectives, and strategies
outlined in this CCP address management of the 55 acres of
Service-owned lands and do not pertain to private lands.
Partnerships
In addition to the PG&E partnership, described above, the Refuge has
benefitted from the work of many scientists who have conducted
research at the dunes. Refuge partners include the California
Department of Fish and Game, Solano and Napa County Mosquito
Abatement Districts, Mills College, University of California (UC)
Berkeley, UC Santa Cruz, UC Davis, the California Department of
Transportation (Caltrans), Center for Natural Lands Management, and
many dedicated volunteers and individuals.
Refuge Setting
The Antioch Dunes were once a large, ancient, aeolian (wind blown)
dune system extending along the southern bank of the San Joaquin
River just east of the town of Antioch (Powell 1983). According to a 1908
U.S. Geological Survey topographic map the bulk of the dunes were
along a two-mile stretch of the river, averaged approximately one-sixth
of a mile wide and totaled roughly 190 acres (Howard and Arnold 1980).
Sardis Unit
USFWS Photo
Antioch Dunes
National Wildlife Refuge
Antioch
San Francisco
Redwood
City
Sacramento
Santa Rosa
San
Rafael
Santa Cruz
Fairfield
Hollister
Woodland
Martinez Stockton
San Jose
Oakland
Salinas
Napa
|ÿ4
tu101
tu50
§¨¦505
§¨¦580
§¨¦80
§¨¦680
§¨¦5
|ÿ1
|ÿ29
|ÿ160
|ÿ1
tu101
Figure 1. Location Map
CA/NV Refuge Planning Office - May 2003 I
C A L IF O R N IA
Are a
En l a rg e d
10 5 0 10 20
Miles 5
Contra Costa Co.
Sacramento Co.
Lake
Alhambra
Sa n Jo aqu in Ri v er
Wilbur Ave.
Burlington Northern/Santa Fe R.R.
West 18th East 18th
Cavallo Dr.
Fulton
Shipyard
Rd.
Figure 2. Antioch Dunes National Wildlife Refuge
CA/NV Refuge Planning Office, May 2003 I
Stamm
Unit
Sardis
Unit
Flow
U.S. Fish and Wildlife Service Lands Pacific Gas and Electric Lands
Approved Refuge Boundary City of Antioch Unincorporated Contra Costa County

Comprehensive Conservation Plan 7
Introduction
Isolation of this sand dune habitat resulted in the development of
species and subspecies of plants and insects that are found nowhere else
in the world.
Around the early 1900s, this biological “island” began to experience a
dramatic change. Human development and sand mining destroyed
most of the dunes that historically reached heights of 120 feet. The
easily-accessible sand was mined to make bricks. Large-scale sand
mining and industrial development continued to fragment the sand
dune habitat until only a small portion of the original ecosystem
remained. A small portion of the dunes were protected from further
development and mining when the Refuge was established in 1980.
However, nonnative weeds encroached on the sand dunes crowding the
few remaining endangered plants. When the Refuge was established,
only a few acres of remnant dune habitat supported the last natural
populations of primrose, wallflower, and Lange’s. The Refuge was open
for public use until 1986 when it was closed to protect the endangered
plants from trampling and wildfires.
Refuge History
140,000
years ago
Sand dunes are formed by winds blowing loose sand off
the coastal strand habitat.
10,000
years ago
Horses, bison, camels, mastodons, and ground sloths live
in the area. Their bones are found in the dunes in 1940.
1772 The Fages expedition finds a Native American village at
the dunes. The habitat is oak woodland. Deer, antelope,
tule elk, and beaver abound in the area.
1776 The de Anza expedition travels through present-day
Antioch and the dunes.
1836 The Los Meganos Land Grant is awarded to Jose Noreiga.
1849 Settlers are encouraged to take up residence on the land
grant. Smith's landing, on land grant land, will later be
called Antioch.
1852 A brick factory is built in town.
1853 A dairy, piggery, sheepfold, and a store are established in
the dunes and a shipyard will be built there later. Wild
oats (Avena barbata, A. fatua) and red-stemmed filaree
(Erodium cicutarium) introduced from Europe are
growing in the dunes. Cattle roam freely in the area
including the dunes.
1860s A vineyard is planted in Antioch Dunes.
1869 The first known botanical visit to the dunes is conducted
by Albert Kellog, a founder of the California Academy of
Sciences.
1889 Two brickyards are established in the Antioch Dunes.
1896 Wallflower is described by E.L. Greene.
8 Antioch Dunes National Wildife Refuge
Chapter 1
1900 Tracks for the Atchison, Topeka, and Santa Fe Railroad
are laid along the southern margin of the dunes. Spur
lines into the dunes facilitate removing sand and bricks.
e l t s i h t n a i s s u R . e l a s r o f d e v o m e r g n i e b s i d o o w d r o c k a O(
Salsola tragus) is found in the Antioch Dunes.
1903 Wilbur Avenue is built, providing road access to the dunes.
1906 The San Francisco Earthquake occurs; much of the city
will be rebuilt with bricks made of sand from the Antioch
Dunes.
1909 The Great Western Power Company builds a transmission
line across the dunes. This company will be acquired by
PG&E.
1915 Three brick-making companies now operate in the dunes.
1930s The Stamm family acquires the western portion of the
sand dunes, including the vineyard. The Stamms will mine
sand from the property for almost half a century.
The dunes are discovered by entomologists from the
University of California and California Academy of
Sciences. Ultimately, 29 new taxa will be discovered in the
dunes.
1933 Various beaches, dance pavilions, wharfs, and recreational
cottages attract visitors to the shore of the San Joaquin
River. Antioch Beach is very popular.
Lange's are discovered. They will be described by John
Adams Comstock in 1938.
1936 John Thomas Howell and Alice Eastwood collect the first
specimens of Antioch Dunes evening primrose which will
be described by P.A. Munz in 1949.
1940 Jack Little buys an eastern parcel of the dunes from the
owners of a brickyard. He builds the Little Corral Bar
from the company's mess hall. Little will mine sand in the
dunes for 33 years.
Insect collectors from all over the west continue
investigating the unique insect fauna found in the dunes.
1947 The Fibreboard Company purchases a parcel in the
Antioch Dunes, clears the oaks, levels the sand, and builds
a paper mill.
Early
1950s
Crown-Zellerbach builds another mill in the dunes. The
City of Antioch buys land from the Stamms and builds a
sewage treatment plant in the dunes.
1955 Life Magazine features the flora and fauna of the Antioch
Dunes.
1976 Lange's is placed on the Federal Endangered Species List.
Comprehensive Conservation Plan 9
Introduction
1977 Mildred Mathias andLincoln Constance describe a state
listed rare plant, Mason's lilaeopsis ( Lilaeopsis masonii)
collected from the dunes.
Richard Arnold starts a capture and release population
study to estimate the number of Lange's on the Antioch
Dunes.
1978 The wallflower and the primrose are listed as endangered
species. The dunes are designated "critical habitat."
1979 The wallflower and primrose appear on U.S. postage
stamps.
Congressman George Miller begins receiving mail from
plant and butterfly fanciers from all over the country.
The Service conducts negotiations with the property
owners to establish a purchase price. The owners are
prepared to sell the property to a developer for the
construction of a marina and condominium complex.
1980 The Refuge is established, the first acquisition ever by the
Service specifically for the protection of plants and insects.
Cost of the 55 acres is $2,135,000.
PG&E plants 445 seedlings of the buckwheat to protect
the few remaining Lange's on its property.
1983 Most of the vineyard planted in the 1860s is restored to
natural habitat.
Arnold (1983a) concludes a capture and release population
study of Lange's started in 1977.
1986 Service personnel and volunteers count 186 Lange's
during the population peak count for that year.
The Refuge is officially closed to all public use because
endangered species are being trampled and illegal
campfires are causing wildfires.
1991 3,000 cubic yards of riverine sand donated by PG&E are
trucked into the Refuge to re-create habitat for the
endangered species.
1992 PG&E donates an additional 4,000 cubic yards of sand to
create new dunes.
1992-1995 Plants of many species native to the area, including the
primrose, wallflower, and buckwheat, are planted on the
new dunes.
1997 Prescribed burning is initiated to combat nonnative weeds.
10 Antioch Dunes National Wildife Refuge
Chapter 1
(Arnold et al. 1983, Arnold pers. com. 1999; Howard and Arnold 1980;
Loredo pers. com. 2000)
Refuge Purpose
The Refuge was established under the authority of the Federal
Endangered Species Act of 1973 which provides for the protection of
endangered and threatened species of fish, wildlife, and plants. In
addition to providing a basis for making compatibility determinations, a
refuge’s purpose also serves as a guide for refuge management and
public use. The Refuge purpose is:
“. . . to conserve fish, wildlife, and plants, including those which
are listed as endangered species or threatened species . . . ” 16
USC § 1534 (Endangered Species Act of 1973).
The Refuge was established in 1980 to protect a unique riverine dune
ecosystem, including designated “critical habitat” and three endangered
species. The 67 acres within the approved Refuge boundary, along with
some lands on the Georgia-Pacific gypsum plant and Kemwater
properties, support the last known natural populations of the
endangered primrose, wallflower, and Lange’s.
Land and Water Conservation Fund money was used to acquire lands.
The acquisition was in accordance with the recovery plan for the three
species (Service 1984).
Related Projects and Studies in the Area
U.S. Fish and Wildlife Service
The Recovery Plan for the Primrose, Wallflower, and Lange’s
In 1984, the Service prepared a Recovery Plan for Three Endangered
Species Endemic to Antioch Dunes, California. The recovery plan
describes the species and sets forth recommendations for managing the
primrose, wallflower, and Lange’s. The plan identified fuelbreak
maintenance (a barrier of cleared land intended to stop the spread of
fire), public recreation, and nonnative weeds as the greatest threats to
the endangered species. Recommendations included:
■ Acquiring the Stamm and Sardis properties;
■ Developing cooperative agreements for habitat management with
landowners adjacent to these parcels;
■ Conducting additional research on the three endangered species to
determine habitat requirements;
■ Monitoring the three endangered species to determine their
population sizes;
■ Possible captive breeding of the Lange’s;
■ Propagating and planting buckwheat, primrose, and wallflower;
■ Rebuilding natural dune substrate and topography by adding sand;
■ Removing nonnative weeds, including the vineyard;
■ Restricting public access to both the Stamm and Sardis Units; and
■ Developing interpretive and environmental education programs.
1999 Service personnel and volunteers count 2,342
Lange's during the population peak count for that
year. This is the highest count on record.
Comprehensive Conservation Plan 11
Introduction
Most of these recommendations were implemented or are in progress.
The only recommendation not fully implemented was developing an
interpretive and environmental education program. Although the
Refuge has developed some interpretive and environmental education
partnerships and programs, funding and staff to fully accomplish this
recommendation have not been available.
Other Agencies
Brannan Island State Recreation Area
Brannan Island State Recreation Area (SRA) was established in 1962 by
the California Department of Parks and Recreation (DPR) and supports
a self-sustaining population of primrose (Riblet pers. com. 2000). The
Recreation Area is about 16 miles north of the Refuge, along the
Sacramento River, Jackson Slough, and Three Mile Slough. The
southern portion of Brannan Island consists of a dredge spoil area.
Sands washed down the Sacramento River (probably from historic
hydraulic mining activities in the Sierra Nevada Mountains) were
dredged to deepen the Sacramento River Deep Water Ship Channel and
deposited on the southern portion of Brannan Island. The dredged sand
on the island is very fine and has been used to manufacture glass.
Walter Knight, a former staff member of the Regional Parks Botanic
Garden, planted primrose on “low dunes” of Brannan Island in 1969, as a
possible solution to the “grave threat sand mining posed” to populations
at Antioch Dunes. James Roof, director emeritus of the botanic garden,
was the inspiration behind Knight’s action to initiate dispersal to remote
dune areas suitable for primrose (Service 1984). Since then, there have
been no management actions to enhance the primrose population.
Although an area surrounding the planted primrose has been fenced,
the primrose that has spread into other areas in the SRA have received
no special protection. The new locations are not aligned with the
existing population and prevailing winds on the island. Therefore, the
seeds were probably not wind-dispersed. DPR believes that rabbits
have spread primrose seeds on the island through their digestive tract
(Riblet pers. com. 2000). The original planting location is in a protected
area, along with several elderberry (Sambucus mexicana), host plant for
the federally endangered valley elderberry longhorn beetle
(Desmocerus californicus dimorphus). Other primrose growing outside
the fenced area have been seen at the edges of pathways and along the
beach. Park personnel have noted that the primrose seem to do better in
these areas of disturbance.
The Regional Parks Botanic Garden at Tilden Regional Park
The East Bay Regional Park District owns and operates the Regional
Parks Botanic Garden in Berkeley. The garden grows both the primrose
and wallflower in small plots of no more than 200 square feet each. The
primrose and wallflower have required diligent maintenance, including
weeding and outplanting, to maintain their numbers.
Montezuma Wetlands
Montezuma Wetlands, near Collinsville, across the river from the
Refuge, is a wetland restoration project demonstrating the beneficial
reuse of dredge material. The project, which is being undertaken by
private entities, will use dredge disposal material from the Federal
channels of the Oakland Harbor and the berths that are maintained by
12 Antioch Dunes National Wildife Refuge
Chapter 1
the Port of Oakland. About 1,800 acres of the site will be restored as
wetland. An additional 50 acres will be used to dewater and desalinate
dredge material for sale to other entities. Dredge material that is resold
will be processed at a facility where the materials will be washed and
cleaned prior to sale and placement. Montezuma Wetlands offers a
potential source for clean sand (to restore dunes) close to the Refuge.
CALFED
CALFED, a consortium of stakeholders and Federal and State agencies,
is developing a plan to address the agricultural, municipal and wildlife
demands on the water supply of the Sacramento/San Joaquin River
Delta (Delta). The Refuge is in the study area for the CALFED plan
and has been specifically identified as a potential area for habitat
restoration under the Ecological Restoration Program of CALFED.
The CALFED Ecological Restoration Program Plan’s (1999) goals
include protecting and enhancing the Refuge and surrounding dunes,
the recovery of state listed rare species including, Mason’s lilaeopsis
(Lilaeopsis masonii), Suisun marsh aster (Aster lentus), delta tule pea
(Lathyrus jepsonii var. jepsonii), and Federally endangered species
including Lange’s, primrose, and wallflower, all of which can be found on
the Refuge.
Comprehensive Conservation Plan 13
Chapter 2 - The Planning
Process
The Planning Process
The process followed for developing this CCP was guided by the Refuge
Planning Chapter of the Fish and Wildlife Service Manual (Part 602 FW
2.1, November 1996) and evolving policy related to the Refuge System
Improvement Act of 1997. Key steps include:
■ Preplanning;
■ Identifying issues and developing vision;
■ Gathering information;
■ Analyzing resource relationships;
■ Developing alternatives and assessing environmental effects;
■ Identifying a preferred alternative;
■ Publishing the draft plan;
■ Documenting public comments on the draft plan;
■ Preparing the final plan;
■ Securing approval of the California/Nevada Operations Office; and
finally,
■ Implementing the plan.
The CCP may be amended as necessary at any time under an adaptive
management strategy. If major revisions are needed, public
involvement and NEPA review would be required.
In a Federal Register Notice, dated December 30, 1998, the Service
announced that it was preparing a plan for the Refuge. The first Refuge
planning update, December 1998, informed the public about the Refuge
and the planning process. When the update was written, Refuge and
planning staff did not anticipate much general interest in, or
controversy over, Refuge management and decided not to schedule a
public scoping meeting, unless requested by the public. Instead, the
planning update encouraged the public to provide comments and
concerns about Refuge management via e-mail, phone, or mail, with the
understanding that the Service would hold a meeting if public interest
in, or controversy over, Refuge management was high. No meeting was
held because the planning update generated no requests for a meeting
and little controversy.
A technical panel was convened in February of 1999 to assemble nearly
20 scientists who have conducted research at the Refuge and other
experts. The panel spent a day discussing the implications of their
research on Refuge management. The panel included university faculty
and staff, consultants, graduate students, other agency personnel, and
Service personnel (Appendix B).
14 Antioch Dunes National Wildife Refuges
Chapter 2
The second planning update, May 1999, described the issues, concerns,
and opportunities identified at the technical panel. A second technical
panel was convened in November 1999 to solicit comments and provide
answers to questions on the draft documents. The third planning
update, July 2000, discussed the goals and objectives. The fourth
planning update, July 2001, announced the upcoming draft CCP and
informed the public about how to comment on the draft CCP. The fifth
planning update, March 2002, announced the upcoming final CCP and
gave the public the choice of receiving either the complete document or
a summary.
The draft CCP and Environmental Assessment (EA) (Appendix C),
were distributed to Refuge partners, adjacent landowners, government
agencies, local jurisdictions, community groups, and private citizens in
August 2001. The public had 30 days from its release to provide
comments. The response to these comments is Appendix D.
Implementation of the CCP began after the finding of no significant
impact was signed. The EA is available on file at the Refuge and with
the California/Nevada Refuge Planning Office in Sacramento,
California.
The CCP will be reviewed by Refuge staff while preparing annual work
plans and updating the Refuge Operational Needs System database.
This database describes the unfunded budget needs for each refuge and
is the basis upon which the Refuge receives funding increases for
operational needs. The plan may also be reviewed during routine
inspections or programmatic evaluations. Results of the reviews may
indicate a need to modify the plan. Periodic review of the objectives and
strategies is an integral part of the plan and management activities may
be modified if the desired results are not achieved. If minor changes are
required, the level of public involvement and NEPA documentation will
be determined by the refuge manager. The CCP will be formally revised
about every 15 years.
Issues
Issues, concerns, and opportunities were identified through discussions
with planning team members, members of the technical panel, other key
contacts, and through the public scoping process. Comments were
received in writing, via e-mail and regular mail. The following issues,
concerns, and opportunities are a compilation of information developed
by the Service throughout the planning process. The most significant
issues identified are nonnative weeds, public use, trespassing, and
wildfires caused by illegal campers.
Issues Identified by the Public
■ Open the Refuge to the public for fishing and swimming.
■ Provide guided tours of the Refuge.
■ Provide opportunities for volunteers.
■ Maintain the Refuge as a sanctuary.
■ Extensive nonnative weeds should be controlled by burning (where
appropriate), herbicide application, and mechanical removal
methods.
■ Restrict native plantings until nonnative weeds are under control.
■ Provide a part-time caretaker to repair fences and practice
nonnative weed control. An off duty fireman could possibly oversee
the refuge and provide a presence on the Refuge.
Comprehensive Conservation Plan 15
The Planning Process
Issues Identified by Refuge Staff, Panel of Experts, and Other Agencies
■ Develop and complete an agreement with PG&E for long-term
management of the 12 acres they own within the approved Refuge
boundary.
■ Control nonnative weeds.
■ Identify and develop techniques for successful restoration.
■ Consult with experts in dune ecology, restoration, and nonnative
weeds.
■ Explore methods of creating sand disturbances in the dunes.
■ Investigate effects of prescribed burning on air quality.
■ Address lack of adequate funding and staff.
■ Determine scope and compatibility of public use.
■ Increase efforts to stop trespassing and vandalism.
■ Conduct more research on the effect of fire on native insects.
■ Explore public use - most are not compatible.
■ Explore possible land acquisition, by fee title or easement.
■ Investigate effects of wildfires.
Resource issues and opportunities were also identified during the
scoping process. The results of this effort are described in Chapter 4,
Problems and Opportunities.
Contra Costa Wallflower on sloping terrain
USFWS Photo
16 Antioch Dunes National Wildife Refuges
Chapter 2
Comprehensive Conservation Plan 17
Chapter 3 - Refuge and
Resource Description

The Refuge is in the Delta which sits in the San Francisco Bay-Delta
Watershed, a 61,000 square mile area of California (CALFED 2001).
The Delta is 750,000 acres of tidal marshland, shallow backwater
swamps, farmland, and municipalities (California Department of Fish
and Game and the Service 1980). The Refuge occupies a unique place
within the ecoregion in that inland dunes are limited within the Delta,
found only in the Refuge area (CALFED 1999).

The Refuge is near the southwestern boundary of the Delta, about five
miles upstream of the confluence of the Sacramento and San Joaquin
Rivers. The Delta contains hundreds of miles of interlaced waterways
and is the major collection point for water that serves two-thirds of
California’s population (California Department of Water Resources
1995).
Before flows were regulated and the rivers channelized, the Delta was
characterized by sluggish river channels, oxbow and floodplain lakes,
swamps, and sloughs. Native fish thrived in weedy backwaters and
large stretches of open water. The region’s dense tules, willows, and
cottonwoods supported more than 250 species of birds and mammals.
The 55-acre Refuge, along with the 12 adjacent acres owned by PG&E
and a few adjacent acres of land, is all that remains of a unique system of
riverside sand dunes that once reached heights of 120 feet and stretched
along two miles of the southern bank of the San Joaquin River east of
Antioch (Roof 1969).
Beginning in the 1880s, Antioch Dunes’ pure sand was systematically
mined for use in brick making and construction. Today, the last
remnants of the dunes are surrounded by a shipyard, a gypsum plant,
and a former sewage treatment plant and vary from zero to 50 feet high.
The Refuge currently exists as an isolated habitat surrounded by
industrial development (Service 1997b). The existing habitat has been
highly altered by sand mining and agriculture, which is reflected in
extensive weediness and the inability to support healthy populations of
native species.
18 Antioch Dunes National Wildife Refuge
Chapter 3

As required by Service planning policy, a wilderness review (Appendix
E) was conducted for the Refuge. None of the Refuge lands were
eligible for wilderness designation.

In an effort to divide the Refuge into areas with similar topographic
features and/or species abundance, the Stamm and Sardis Units have
been divided into different management areas (MA) (Figures 3 and 4).

The Stamm Unit terrain is characterized by rolling dunes ranging from
zero to 50 feet high, as measured from the river water surface elevation.
The Sardis Unit, which ranges from 1 to 50 feet high is between two
higher parcels owned by PG&E. The PG&E parcels are about 80 feet
above the water surface elevation. It is likely that the PG&E parcels
more closely resemble the native topography than the Refuge units
because the PG&E parcels were never mined for sand (Loredo pers.
com. 1999). In 1927, the northern portion of the eastern PG&E parcel
was leveled to construct a tower. The central and southern portions of
this parcel, two or three acres, were never developed and are the only
sections in the Refuge area that retain original height and contours
(Arnold et al 1983). It is presumed that the western PG&E parcel is
naturally fairly level.

The aeolian sand at the Refuge is contiguous with the sheer aeolian sand
underlying much of the flat lands between the Mount Diablo foothills
and the western margin of the Delta. Most of the exposed aeolian sand
near Antioch accumulated between 10,000 and 40,000 years ago, during
the late Pleistocene period. Atwater (1982) theorized that most of the
exposed sand at the Refuge accumulated during the most recent major
glaciation of the Sierra Nevada. The retreating glaciers deposited
glacially eroded sand and silt onto the floodplains of the Central Valley’s
rivers and drainages. Summer winds sweeping the floodplains would
have picked up the sand and deposited it as dunes, generating the dune
field of eastern Contra Costa County.
Evidence of at least two discrete episodes of aeolian deposits is exposed
in a river bluff adjacent to the Refuge. About 50 feet of young sand
dunes, from the last glaciation, overlies 5 to 6.5 feet of older sand dune.
Though dunes could have formed near Antioch at least five times during
the last 500,000 years, the penultimate deposits probably occurred
140,000 years ago (Atwater 1982). Thus a hiatus of 100,000 years may
separate the last two episodes of sand dune formation at Antioch
(Atwater 1982). The dunes were formed by ancient deposits of glacial
sands carried downriver from the Sierra Nevada, left isolated along the
river after the Mojave Desert receded in prehistoric times. Over
thousands of years, ocean winds and bay tides slowly shaped these sands
into high dunes. Isolation of this sand dune habitat resulted in the
development of species and subspecies of plants and insects that are
found nowhere else in the world.
HARDPAN #2
SCARIFIED
TRIANGLE
HARDPAN #1
NORTH
EAST
HARDPAN #3
SOUTH OF PATH
EAST
PLATEAU
RESTORED VINEYARD
HARDPAN #4
PLATEAU
1995
DUNES
ACCESS ROAD
ENTRY
CAR BODY
HARDPAN SLOPE
RIVER SLOPE
TRIANGLE
SECTION
TO OAK
BLOWOUT
VINEYARD
PLATEAU
RIVER
2.63
4.14 1.18
2.65
3.58
2.33
2.50
1.56
5.89
2.88
2.80
0.20
2.19
3.43
1.19
1.36
1.18
S a n J o a q u i n R i v e r
Georgia-
Pacific
Gypsum
Plant
Ful ton Ship yar d Ro ad
Fulton
Shipyard
Wilbur Avenue
Burlington Northern / Santa Fe R.R.
Minaker Drive
Figure 3. Management Areas with Acreages - Stamm Unit - Antioch Dunes National Wildlife Refuge
100 0 100 200 300 400 500 I
Feet
CA/NV Refuge Planning Office - May 2002
Note: All units are in acres.
Approved Refuge Boundary Management Areas

Carpenter and Cosby (1939) mapped the Refuge area as Oakley Sands.
Soil types at the Refuge have been classified as ranging from sand to
sandy-loam; pH averages 6.4 (range 5.6 to 7.0). The Service hired a
contractor to collect and analyze soil samples from several sites at the
Refuge. The soils report (Jones and Stokes 2000) indicated that the
Refuge lacks a true soils association. The native soils have been severely
mined, from a height of about 120 feet to a current height at about 10 to
50 feet.

The Antioch area has a modified Mediterranean climate with hot dry
summers and moist, mild winters. Rainfall averages 12.5 inches
annually, falling mainly from November through April. Typically, the
months of May through September are dry. The average annual
temperature is 61.8°F with an average annual maximum temperature of
74°F. Average high temperatures in the area range from above 90°F in
July, August, and September to the mid-50s°F in December and January.
The hottest recorded temperature is 114°F, and the lowest recorded
temperature is 14°F. Summer winds blow from the river from the west
or northwest at an average of 10 to 20 mph.

Because the area is exposed to winds both from the west and east, and
the terrain provides little protection from the wind, the Antioch area has
good air flow. Average wind speeds in the Antioch area are relatively
high and calm conditions are infrequent. The air quality near Antioch is
generally good. However, there are point sources of air pollution near
the Refuge that potentially affect air quality on the Refuge. The Sardis
Unit is adjacent to and generally downwind of the Georgia-Pacific
gypsum plant which emits gypsum dust that covers vegetation in
surrounding areas. The Southern Company power plant, owned by
PG&E until 1999, is about one mile from the eastern boundary of the
Refuge. The Southern Company plant emits benzene (35 lbs/yr) and
formaldehyde (1,700 lbs/yr) (BAAQMD 1999a). Air pollution generated
by the Refuge is caused by temporary, short term disturbances, such as
annual prescribed burning and earthmoving activities. There is
currently limited public use allowed on the Refuge and there are
minimal maintenance activities; on-site vehicular emissions are
infrequent.
The State Air Resources Board has statewide responsibility for air
quality in the area, and the Bay Area Air Quality Management District
(BAAQMD) has permitting authority for stationary air pollutant sources
in the region. The BAAQMD regulates federally regulated air
pollutants, particulate matter, organic compounds, nitrogen oxides,
sulfur dioxide and oxides, carbon monoxide, hydrogen sulfide, ground
level ozone, and acid deposition.
Air quality in Contra Costa County is generally good. Because the air
quality monitoring station closest to the Refuge (in Pittsburg, CA) has
exceeded air pollution standards for ozone twice for the maximum one-hour
emission and once for the maximum eight-hour emission, the
county is a nonattainment area (BAAQMD 1999b). Contra Costa County
contains a multitude of air pollutant sources. Controls placed on
automobiles and stationary sources of air pollutants, such as factories
22 Antioch Dunes National Wildife Refuge
Chapter 3
and refineries, as well as on nonpoint sources such as paints, solvents,
and gas stations, have not resulted in all air quality standards being
attained in the Bay Area. Inventories of these sources have been
prepared by the BAAQMD (BAAQMD 1999a and 1999b). Mobile
sources, including automobiles, busses, and trucks contribute about 50
percent of the air pollutants and air toxins (Richardson pers. com. 2001)
except for sulfur dioxide, which is primarily generated by petroleum
refining and power plants (deBecker pers. com. 2001).
The Antioch area contains a large portion of the industrial sources of
pollutants within Contra Costa County, and is downwind of both the
greater Bay Area and the Diablo Valley. As a result, ozone levels exceed
both the Federal and State standards. Carbon monoxide, sulfur dioxide,
nitrogen dioxide, lead, and hydrogen sulfide levels are within the
Federal and State standards.
There is concern that gypsum dust from the adjacent gypsum plant may
affect plant health, particularly that of the endangered species, by
affecting soil chemistry and/or photosynthesis (gypsum is a common
fertilizer and soil additive). Many plants on the PG&E parcels and
Sardis Unit are covered with a fine layer of gypsum. The gypsum
suspended in the air is also a health concern for Refuge staff and
visitors.

The Service’s Denver Engineering Division contracted for a
contaminants survey of the Refuge in 1999 with Clark and Witham.
Phase I of the survey included site reconnaissance, reviewing historical
use of the site, and reviewing records and reports of environmental
incidents at or near the Refuge. Phase II included the collection and
analysis of soil and ground water samples from the Refuge. Past land
uses had indicated that the survey should pay special attention to
potential creosote, pesticides, and asbestos contamination.
The survey found that no environmental incidents involving the release
of chemicals to the soil or ground water are recorded to have occurred on
the Refuge nor on the properties owned by Fulton Shipyard, Georgia-
Pacific, the railroad, or the former sewage treatment plant. Soluble
metals and other contaminants are recorded as present in the soil and
ground water at the Kemwater plant.
Pesticides, creosote, and asbestos testing of soil samples gave results
below detection limits set by the analytical laboratories, except for a soil
sample from the Sardis Unit which indicated the presence of chlordane.
The chlordane encountered on the Sardis Unit, based on past land use
and the half life of this chemical, is most likely a remnant of past
agricultural land use. Chlordane was applied directly to soil or foliage to
control a variety of insect pests on corn, citrus, deciduous fruits and nuts;
for home, garden, and ornamentals; lawns, turf, ditch banks, and
roadsides. Groundwater samples for pesticide and creosote were below
the detection limits set by analytical laboratories. Chrysotile, however,
was found at about 20 feet below the surface at Hardpan 1 and 2 MAs
(Stamm Unit, Figure 3). Chrysotile is a natural asbestos found
throughout California. It is common to find chrysotile in soil and
groundwater in the San Francisco Bay Area, and given the depth and
location of the chrysotile, the chrysotile observed in the groundwater at
these two sites appears to be natural. Although the survey found no
contaminant issues that currently affect the Refuge, the report
Comprehensive Conservation Plan 23
Refuge and Resource Description
recommends that further contaminants monitoring should concentrate
on ground water monitoring along the eastern boundary of the Sardis
Unit (adjacent to the Kemwater Plant) and along the southern boundary
of the Stamm Unit (adjacent to the former sewage treatment plant).

The San Joaquin River forms the northern boundary of the Refuge. The
Refuge’s tidally influenced river frontage is about two-thirds of a mile
long. The riparian corridor generally, is less than 10 feet wide due to the
tall and steep embankments along the river’s edge. Like most of the
Refuge, the riparian corridor has been altered and contains nonnative
weeds.
The San Joaquin River adjacent to the Refuge is affected by the saline
conditions of the ocean and, together with the rest of the Delta outflows,
flows at around 32,000 cubic feet per second in winter (California
Department of Water Resources 1995). Tides in the area cause water
level fluctuations from about 3 feet above sea level at high tide to about
2.2 feet below sea level at low tide during a typical tidal cycle. The
groundwater beneath the Refuge is predominately influenced by the
level of the San Joaquin River. As the ocean tides raise and lower the
surface elevation of the river, the groundwater level fluctuates in
response. Groundwater level at Hardpan 1 MA is approximately 15 feet
below the surface, 27 feet at the Restored Vineyard MA, and 17 feet at
the Car Body MA on the Stamm Unit (Clark and Witham 1999).

Refuge management requires very little water. No water is currently
being used for irrigation. Water, used for fire suppression, is supplied
from a hydrant by the southern boundary of the Stamm Unit. The
Refuge is in the Contra Costa Water District.

Historic accounts of the Refuge indicate that oak woodland was the
primary vegetative community at the Antioch Dunes. The presence of
oak woodland suggests that there was a
stabilized substrate, however, it is also
known that native flora, such as
wallflower, primrose, butterweed
(Senecio sp.), and California matchweed
(Gutierrezia californica) would have
required dynamic substrate as well. It is
possible that slumping caused by
weather, gravity, falling trees, wind
erosion, and natural plant senescence
would have provided occasional open
areas of sand that would have been
colonized by the sand-loving primrose.
It is not known what role, historically,
fire played in the Antioch Dunes
ecosystem.
Three main habitat types are found
within the 67 acre approved Refuge boundary (Figure 5): littoral (owned
by State Lands Commission), riparian, and unique stands at Antioch
Dunes (Sawyer and Keeler-Wolf 1995). The littoral zone, along the
Littoral zone where Mason’s lilaeopsis is found.
USFWS Photo
S a n J o a q u i n R i v e r
S h i p y
a r d R
d .
F u l t o n
Burlington Northern / Santa Fe R.R.
Wilbur Ave.
Minaker Dr.
100 0 100 200 300
Meters
CA/NV Refuge Planning Office - May 2002 I
Figure 5. Three main habitat types at Antioch Dunes National Wildlife Refuge.
Approved Refuge Boundary
PG&E Property
Riparian
Antioch Dunes Unique Stands
(Sawyer, Keeler-Wolf 1995)
Littoral Zone

Comprehensive Conservation Plan 25
Refuge and Resource Description
river’s high and low watermarks, contains a state listed rare plant,
Mason’s lilaeopsis as well as other rare species including Suisun marsh
aster (Aster lentus), Delta mudwort (Limosella subulata), and Delta tule
pea (Lathyrus jepsonii var. jepsonii). Other littoral zone species include
cattail (Typha angustifolia), tufted hairgrass (Deschampsia cespitosa),
alkali marsh butterweed (Senecio hydrophilus), and low club rush
(Scirpus cernuus).
The riparian area is characterized by native species such as coast live
oak (Quercus agrifolia), narrow-leaved willow (Salix exigua), arroyo
willow (Salix lasiolepis), toyon (Heteromeles arbutifolia), and
elderberry (Sambucus mexicana). A steep embankment at the river’s
edge provides a narrow space for riparian vegetation. The riparian
corridor has been altered and contains nonnative weeds such as
oleander and pampas grass. Irregularly shaped pieces of broken
concrete slabs have been placed on the river bank at the west end of the
Stamm Unit, perhaps serving as revetment.
The “unique stands at Antioch Dunes” (a separate cover type) as
described by Sawyer and Keeler-Wolf (1995) consist of scattered forbs
and grasses which form a ground canopy and uplands consisting of
stabilized or partially stabilized dunes. In addition to the primrose,
wallflower, and buckwheat, other common native plants in the dunes
include elegant clarkia (Clarkia unguiculata), California poppy
(Eschscholzia calfornica), California croton (Croton californicus),
Grindelia (Grindelia sp.), deerweed (Lotus scoparius), telegraph weed
(Heterotheca grandiflora), California matchweed (Gutierrezia
californica), and silver bush lupine (Lupinus albifrons).
These native plants, which composed these “unique stands,” still exist on
the Refuge, mostly in areas that have had the least amount of sand
mining or human degradation or in areas that have been intensively
managed. The unmined fringe areas along the river in the Stamm and
Sardis Units have concentrations of native species (Service 1997b). The
highest proportion of native species on the Refuge, including the
primrose, wallflower, buckwheat, croton, deerweed, and many others
(Appendix F) have traditionally been found on the open dune area of the
Blowout MA (Stamm Unit, Figure 3). The Blowout MA most represents
the historical ecology of the original riverine dunes including the
original topography, sandy nutrient-poor soils, and wind currents. The
native plants in this MA also seem to be shorter and less robust than in
other areas, indicative of plants in this ecological region.
The viability of native plants on the Refuge is one of the Refuge’s
primary concerns. Once a diverse habitat for many types of insects and
wildlife, the dunes now support thriving nonnative weed populations
that do not support the same invertebrate diversity (see invertebrates
section).
Before the Refuge was established, the areas with the highest
concentration of nonnative weeds were disced (turning large discs
through the soil using heavy equipment) annually (Powell 1983). This
area included the unmined southern portion of the Sardis Unit, along
with its mined-out pit. Some of these areas have been colonized almost
entirely by nonnative weeds. As a result, the Refuge no longer uses
discing as a weed control measure. Nonnative weeds dominate some
areas of the Refuge. Primarily of concern are ripgut brome (Bromus
diandrus), yellow starthistle (Centaurea solstitialis), vetch (Vicia spp.),
and Russian thistle (Salsola tragus).
26 Antioch Dunes National Wildife Refuge
Chapter 3

The Refuge provides important habitat for many types of wildlife,
including mammals, reptiles, and resident and migratory birds.
Historical accounts indicate that mink (Mustela vison), desert cottontail
rabbit (Sylvilagus auduboni), beaver (Castor canadensis), muskrat
(Ondatra zibethica), opossum (Didelphis marsupialis), weasel (Mustela
frenata), and skunk (Spilogale gracilis) were found at the Refuge.
Recent observations of mammals have been limited. Gopher
(Thomomys bottae), gray fox (Urocyon cinereoargenteus), Beechy
ground squirrel (Spermophilus beecheyi), coyote (Canis latrans),
blacktail jack rabbit (Sylvilagus bachmani), muskrat, raccoon (Procyon
lotor), Townsend’s mole (Scapanus townsendi), weasel, and red fox
(Vulpes fulva) are mammals recently seen at the Refuge. Gopher
mounds and rabbit droppings abound. Fox and squirrel burrows and
dens are also commonly observed. Beaver have also been seen along the
river’s edge.
In 1977, Papenfuss, then a graduate student at UC Berkeley, completed
an inventory of Refuge reptiles, including the California legless lizard
(Anniella nigra), side-blotched lizard (Uta stansburiana), coast horned
lizard (Phrynosoma coronatum), San Joaquin whipsnake (Masticophis
flagellum ruddocki), glossy snake (Arizona elegans), western whiptail
lizard (Cnemidophorus tigris), and the fence lizard (Sceloporus
occidentalis). In 1982, Papenfuss followed up this inventory with an
effort to trap herpetofauna on the Refuge and identify which species
were still present. Only two species of reptiles were found at that time,
side-blotched lizards and fence lizards. Since then, few reptiles have
been reported or collected on the Refuge. No amphibians were found,
however, historical collections for the Refuge include the western toad.
Two California legless lizard sightings occurred in 2000. Fence lizards,
gopher snake (Pituophis melanoleucus), and racers (Coluber
constrictor) have been seen on the Refuge recently (Loredo pers. com.
2000b).
Numerous bird species have been observed on the Refuge, including
migratory and resident birds. Appendix G lists birds found at the
Refuge. Gadwalls (Anas strepera) and mallards (A. platryhynchos)
have also been observed nesting on the Refuge (Buffa pers. com. 2001).
!
The Service’s Sacramento/San Joaquin Estuary Fishery Resource Office
has monitored fish populations in the San Joaquin River from a beach
seining station on the Refuge monthly since 1979. Listed species caught
offshore of the Refuge include winter-run chinook salmon
(Oncorhynchus tshawytscha) (federally and state listed endangered),
delta smelt (Hypomesus transpacificus) (federally and state listed
threatened), steelhead trout (O. mykiss) (federally threatened), and
Sacramento splittail (Pogonichthys macrolepidotus) (federally
threatened). The complete list of fish species found at the Refuge
sampling station is included as Appendix H.
" # $

Antioch Dunes has been known as an entomological hotspot since the
1930s when entomologists began collecting specimens in what is now the
Sardis Unit. The area attracted attention for its large and colorful
Comprehensive Conservation Plan 27
Refuge and Resource Description
species with desert affinities. In the 1930s, many species of wasps and
flies, particularly the giant flower-loving fly (Rhaphiomydas trochilus)
were completely new to the region’s collectors. A total of 27 taxa were
described from Antioch Dunes during this decade. Today we know that
eight of these taxa are endemic to Antioch, four are now extinct, three
are of uncertain status, and the eighth is Lange’s, discussed in the
Endangered Species section.
J.A. Powell and associates conducted an insect survey at the Refuge
from 1976 to 1982, following a seasonal visitation schedule similar to that
of past collectors but with a higher frequency during late summer and
fall, compiling 94 visits representing all months (Powell 1983). Because
no complete historical list of insects for the Antioch area exists, Powell
chose 14 families to form a basis of comparison with historical
collections, based on their sand-dune affinity characteristics. Three eras
of insect collections were examined in detail: 1933-39 (extensive sand-mining),
1948-54 (extensive industrial buildup), and 1976-84 (final sand-mining
and extensive weediness).
Powell found no significant difference between the diversity (number of
species) recorded in the three selected eras. He noted, however, that
collectors of early eras did not sample thoroughly; data indicate that in
the 1930s workers overlooked small and nocturnal species, while those of
the postwar era overlooked small species to a lesser degree and tended
to ignore some families. Therefore, Powell suggests that decline in
diversity is best documented by species disappearance. Only 69 percent
of the 279 species recorded more than once in previous surveys were
observed during Powell’s 1976-82 survey. Loss of insect species at the
Refuge happened surprisingly early – 35 species have not been sighted
since the 1930s – and showed no marked correlation with an exploitation
event. The extinction rate was gradual until the period of his study,
when it appeared the extinction rate rapidly increased.
In January 1995, Wes Maffei of the Alameda County Mosquito
Abatement District began investigations to assess the presence or
absence, approximate abundance, and the distribution of special status
insects at the Refuge (Maffei 1997). Though a total of 249 insect taxa
were identified, only three special status taxa were found: the robber fly
(Efferia antiochi), the scarab beetle (Polyphylla stellata), and Lange’s.
Maffei found only 35 percent of species that Powell recorded in his 1976-
82 surveys in the major families that were investigated. In particular,
Maffei found a decline in native bee species, the pollinators of most of
the native plants. Powell believes the declines are the result of
nonnative weeds and lack of soil disturbance (Powell pers. com. 1999).
Maffei noted this as well; in the 1995 Dunes MA (Stamm Unit, Figure 3),
an increasing loss of insect species occurred as the nonnative weed cover
increased with each successive season, resulting in minimal sand
movement (Maffei 1997, Maffei pers. com. 2000).
According to Maffei’s study, a number of insects have colonized the
Refuge since the industrial buildup and sand mining of the early 1950s.
This would be expected of species that occupy weedy habitats, but even
among the flies and wasps, several newcomers have been recorded. This
is best documented in spider wasps (Family Pompilidae) where the
diversity clearly increased from entomologist collections 30 years ago.
Maffei’s insect list is included as Appendix I.
28 Antioch Dunes National Wildife Refuge
Chapter 3

The three federally listed endangered species–wallflower, primrose, and
Lange’s – are found within and near the approved Refuge boundary.
The California Natural Diversity Database also lists twelve species that
are Federal “species of concern” at the Refuge, which have no protection
under the Endangered Species Act: the Antioch Dunes anthicid beetle
(Anthicus antiochensis, last seen in 1953 and probably since extinct or
extirpated from this location), San Joaquin dune beetle (Coelus gracilis,
last seen in 1974 and probably since extinct), the Antioch cophuran
robberfly (Cohpura hurdi, last seen in 1939), Antioch efferian robberfly
(Efferia antiochi, last seen in 1959), yellow-banded adrenid bee (Perdita
hirticeps luteocincta, last seen in 1936 and probably since extinct),
Antioch adrenid bee (Perdita scituta antiochensis, last seen in 1977),
Antioch mutilid wasp (Myrmosula pacifica, last seen in 1952), Antioch
specid wasp (Philantus nasalis, last seen in 1959), Middlekauf ’s
shieldback katydid (Idiostatus middlekaufi, last seen in 1965), the
Suisun marsh aster, Mason’s lilaeopsis, and the delta tule pea. The
California Natural Diversity Database also lists three State listed
species that have been found within or near the approved Refuge
boundary. These species include Mason’s lilaeopsis (rare), primrose
(endangered), and the wallflower (endangered).
Lange’s Metalmark Butterfly - Apodemia mormo langei
Background
The Lange’s was first discovered in 1933 and was described five years
later. In June 1976, this local subspecies was one of the first eight insects
to be listed as endangered under the Federal Endangered Species Act.
Following the listing, the Lange’s remnant habitat was purchased by the
Service and designated a Refuge (Powell and Parker 1993). Lange’s
continue to inhabit the Refuge, with their populations concentrated in
the 1992 and 1993 Dunes at the Sardis Unit, and the Blowout MA and
1995 Dunes at the Stamm Unit (Figures 3 and 4). The Refuge, in
addition to the PG&E property and a
portion of the Kemwater property
provides about 70 acres of suitable
habitat and constitutes the entire
present range for the Lange’s.
Lange’s, like most butterflies, has a close
relationship with its larval food plant, the
buckwheat, and produce one brood per
season. Adults typically begin to emerge
in late July or early August and can be
observed until mid-September.
Numbers typically peak two or three
weeks following the earliest emergence
of a butterfly from a pupal case. The
peak in male emergence is generally
earlier than that of females (Powell and
Parker 1993). They live for
approximately one week during which
they feed, mate, and locate the host
buckwheat on which to deposit the eggs.
Lange’s Metalmark Butterfly
R.A. Arnold
Comprehensive Conservation Plan 29
Refuge and Resource Description
Female Lange’s lay eggs throughout the adult flight period. The gray
eggs are deposited, in clusters of two or four, on the stem axils of the
lower half of the buckwheat, where the foliage is withered. The eggs
remain attached and dormant until the rainy season, at which time new
growth of buckwheat appears, the eggs hatch and the larvae crawl to the
base of the plant where they overwinter and feed on new foliage (Arnold
1983b). The larvae are nocturnal feeders and feed on new plant growth
through the winter and spring. Pupation occurs in midsummer in the
litter at the base of the buckwheat (Service 1984).
Powell found that adults of both sexes are perchers and are capable of
long flights between perches (Service 1984). The majority of males
move locally (less than 100 feet) while females may travel up to 1,300
feet. Both sexes prefer buckwheat flowers as perches and as a nectar
source. Females tend to be more mobile, visiting a greater variety of
secondary nectar sources and searching for egg-laying sites. Males, on
the other hand, tend to perch and aggregate more than the females.
The primary limiting factors for the Lange’s are availability of nectar
sources for adults, adequate host plants for egg-laying, and sufficient
food for larvae (Service 1984). The highest density of buckwheat on the
Refuge can be found in open areas, where nonnative ripgut brome and
yellow starthistle can be found. Invasion by nonnative weed is
detrimental to the Lange’s because it reduces the amount of suitable
buckwheat stands available for habitat. Modification of the
microclimate at the base of the buckwheat plants, which is also affected
by nonnative weed encroachment, also seems to reduce the viability of
the larvae (Arnold and Powell 1983). Moreover, additional losses of
buckwheat were caused by past discing for fuelbreaks and by wildfires.
At the Sardis Unit in 1976, a wildfire consumed some of the Lange’s
habitat, but the Lange’s has managed to regain its former numbers. In
1999 a wildfire in the Blowout MA of the Stamm Unit destroyed part of
the best Lange’s habitat. The buckwheat quickly resprouted and
Lange’s are beginning to move back into the area, presumably from
adjacent management areas that were not affected by the wildfire.
Population Size and Status
Prior to 1985, population estimates for the Lange’s were obtained from
mark and recapture methods used by R.A. Arnold (1983a). From 1977 to
1983, Arnold documented a decline from more than 2,000 individuals to
fewer than 400 reproducing individuals (effective adult population
number) (Arnold 1983a). Arnold concluded that the Lange’s population
decline was linearly correlated with the loss and alteration of habitat.
Also, a trend analysis suggested that if then current habitat conditions
continued, the extinction of the Lange’s at the Sardis and Stamm Units,
the PG&E parcels, the Georgia-Pacific gypsum plant, and Kemwater
property, could have occurred within one to five years (Arnold 1983a).
Then, in 1985, Arnold documented a Lange’s population increase at both
the Sardis and Stamm Units, 1.6 times greater and 2.2 times greater,
respectively, than in 1984. Since the population rebounded from its low
in 1982, Arnold theorized that at least 400 is a viable, self-sustaining
population size for the Lange’s (Second Technical Panel 1999).
Arnold conducted a captive breeding program for the Lange’s in the
early 1980s, following the low counts. The program was discontinued
after one season because habitat improvement was considered a more
effective means of increasing the Lange’s population (Arnold pers. com.
2001, Arnold 1985, Arnold 1981).
30 Antioch Dunes National Wildife Refuge
Chapter 3
It should be noted that Arnold’s population count methodology is
different from the Refuge staff ’s current low impact peak count
methodology that began in 1986 (Figure 6). Arnold captured, counted,
and marked the Lange’s daily. He could distinguish which Lange’s had
been counted already and which had not. Population estimates were
calculated using these counts. The Refuge’s current methodology
counts Lange’s once a week during their flight period (August to
September) and uses the highest count during those surveys as the
year’s peak count, without distinguishing between individuals that have
already been counted (Arnold pers. com. 2001). The peak count of the
adult butterflies are used as an annual index of the relative size of the
population. The highest peak count was in 1999 with more than 2,342
Lange’s counted. Arnold’s population count could be as much as five to
ten times the Refuge’s weekly peak count. The different sampling
methods cannot be directly compared (Parker pers. com. 2000). Table 1
provides a summary of general trends for the three endangered species.
Antioch Dunes Evening Primrose, Oenothera deltoides spp. howellii
Background
The primrose is a member of the Onagraceae family, subgenus Anogra.
In 1949, the primrose was recognized as a separate variety by Munz. In
1962, Klein distinguished it as a subspecies. The primrose was federally
listed as endangered in 1978. The primrose is endemic to Antioch
Dunes; its naturally occurring population is confined to the two disjunct
units of the Refuge, the PG&E parcels, and a portion of the Kemwater
property. The subspecies has also been grown at the East Bay Regional
Parks Botanic Garden at Tilden Regional Park in Berkeley since 1970,
and introduced to Brannan Island SRA, Point Reyes National Seashore,
and Brown’s Island in the Delta. Of these sites, the primrose persists
only at Tilden Regional Park and Brannan Island.
! %&'
(

)*
)
# +
0
500
1000
1500
2000
2500
Peak Count
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
Year
Stamm Sardis PG&E West PG&E East
Comprehensive Conservation Plan 31
Refuge and Resource Description
The primrose is a short-lived perennial, with some individuals persisting
for several years. Arnold (pers. com. 1999) believes that bees are the
primary pollinating agents at the Refuge. Although hawkmoths were
not known on the dunes until 1983, they have been reported as
pollinators of other Oenothera species. However, their role as primrose
pollinators has not been documented. Studies are needed to determine
the phenology and pollinators of this subspecies.
Because the primrose prefers disturbed sites with nearly pure sand, it is
vulnerable to nonnative weed encroachment. Greene (1995) found no
primrose seedlings around mature primrose that were surrounded by
nonnative weeds, yet seedlings were found
near about 40 percent of mature primrose that
were not surrounded by weeds. Greene
determined that nonnative weeds compete
with the primrose seedlings for water and
light, resulting in reduced seedling
germination and survival. Greene also
determined that removing nonnative weeds
around adult primrose enhanced germination
rates. Weeds also have a negative impact on
seedling germination success because they
stabilize the dunes. Slowik (pers. com. 1999)
confirmed the primrose’s need for regular
disturbance by treatments on seedlings grown
under cultivation. Slowik found that primrose
seedlings germinated more readily in sand
when the sand was disturbed and turned over.
Factors that may limit primrose reproduction
were investigated in 1993 by Pavlik and
Manning. Although they identified low
genetic variation and limited pollinators as potential factors limiting
seed production, seed production was not considered a limiting factor
for primrose reproduction. Pavlik et al. (1988a), Pavlik et al. (1993), and
Pavlik and Manning (1993) also studied the seed bank dynamics, seed
production, and seedling demography to assess the limitations on
primrose growth. They found that more than half the ovules that were
initiated failed to become seeds because effective pollinators were not
available. Their work also indicated that substrate makeup and
exposure were not critical to primrose seed germination, though
competition with ripgut brome for light and moisture was. Although
Antioch Dunes evening primrose
USFWS Photo
Table 1. General Trends for Refuge Endangered Species
Species Population Status Current Threats
Lange's Has generally been stable, peak counts in 1999 were the
highest since surveys began in 1987. Despite this high,
1999 Stamm Unit counts were low as a result of a 1999
wildfire that swept through the unit
Wildfire and nonnative
weeds.
primrose Natural populations of self-reproducing individuals have
generally been declining since 1992.
Nonnative weeds and
lack of substrate
disturbance.
wallflower Cyclical, but generally stable. Nonnative weeds.
32 Antioch Dunes National Wildife Refuge
Chapter 3
substrate makeup was not critical for seedlings to germinate, they found
that primrose only reached reproductive maturity on sandy soils.
Primrose produced many viable seeds, but seed output production over
two years ranged from 26 percent to 37 percent of the maximum. Other
factors, such as weather and predispersal seed predation, also
contributed to lowered seed production, but lack of pollinators was
believed to play a role.
The Service has been conducting an annual primrose census to track
population changes since 1985 (Figure 7). In an effort to reverse the
decline in primrose populations, the Service began outplanting the
primrose by collecting seeds from the Refuge, growing them in the
Service nursery and contract nurseries, and planting the seedlings at
the Refuge.
Population Size and Status
From 1984 to 1991, the total primrose population was estimated to range
from 4,300 to 5,800 individuals. During this time, total primrose counts
on the Refuge’s Stamm Unit were conducted every other year. During
odd-numbered years, primrose numbers in the Stamm Unit were
roughly estimated from transect counts. Figure 7 shows actual numbers
of primrose counted during these years, odd numbered years are under-represented
on the graph. In 1992, the Service observed a dramatic
decline to 1,200 individuals and began outplanting primrose seedlings.
Since then, a complete count of primrose has been conducted every year.
In 1997, the primrose population reached a low of 455 individuals. This
marked the eleventh year of general decline in the number of primrose
at the Refuge since 1986. In 1998, the primrose population increased to
785 individuals, and the downward trend had ended. Primrose plantings
in December 1997 were probably a bigger factor in this increase than
natural reproduction. The steady decline of noncultivated primrose
continues today. Nonnative weed encroachment continues to be the
largest problem affecting the primrose (Table 1).
Contra Costa Wallflower, Erysimum capitatum spp. angustatum
Background
The wallflower, an herbaceous plant in the Brassicaceae family, is a
biennial or short-lived perennial; individuals die after setting seed in
their second year. The wallflower was originally described in 1896 by E.
L. Greene and modified in 1958 by George Rossbach. Like the primrose,
the wallflower is endemic to the Antioch Dunes. The wallflower was
listed as endangered in 1978. The entire known wild population of the
wallflower exists at the Refuge and adjacent PG&E and Kemwater
lands.
Little is known about the reproductive phenology of the wallflower.
Germination may occur in October, and leafing from October through
December. Budding occurs in February, while flowering begins in
March, peaking in April or May. A variety of different insect species
have been observed visiting the plant and carrying pollen away with
them. Fruiting begins in April and peaks in July. Seeds are wind-dispersed
beginning in mid-May and peaking in September
(Endangered Species Information System 1996).
Contra Costa Wallflower
USFWS Photo
Comprehensive Conservation Plan 33
Refuge and Resource Description
The wallflower grows in soil types classified as sand to sandy loam with a
pH averaging 6.4 (range 5.6 to 7.0). Precise information about the
species’ particular requirements is not known at this time. Service
personnel have observed the wallflower growing in steep areas of
unstable sand, especially on north-facing slopes immediately adjacent to
the river (Service 1984). These slopes are generally not as densely
vegetated and may enable the wallflower to compete more effectively
for resources. Rossbach (1958) believed that the wallflower was
restricted to stable dunes of fine sand containing some clay. The habitat
was characterized as “sparse herbs and shrubs,” or less often pasture
grasses, herbs, and scattered live oaks. Johnson (1978) suggested that
reproducing individuals occurred primarily on uneven sites (i.e., river
front bluff faces and edges).
Although current populations of wallflower at the Refuge seem to be
concentrated on steep, north-facing slopes by the river, wallflower at one
time grew on flat terrain in an excavated area within the dunes on the
Kemwater property (Figure 4). Today there are individual plants
growing 160 to 660 feet away from the river bank in a flat hard pan area
of the Refuge. In these areas the hard pan has been broken and the
loose, sandy soil below has been exposed. A large stand of wallflower is
found on the East PG&E parcel adjacent to the Refuge. This stand is
atop and over a ledge leading down to the San Joaquin River. Although
their population is now self-sustaining, overall, the wallflower appears to
be more physically restricted within the dunes than the primrose.
Not much is known about wallflower pollinators except that they are
bees that nest in open banks. Unlike other Brassicaceae, which are
typically pollinated by specialized insects, the wallflower does not
require a specific pollinator.
0
1000
2000
3000
4000
5000
6000
Total Count
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
Year
Stamm Sardis PG&E East PG&E West
! ,& #
# +
34 Antioch Dunes National Wildife Refuge
Chapter 3
The wallflower is grown at the Botanic Garden at Tilden Regional Park.
It was found to be the most adaptable of the wallflowers cultivated.
Unlike the primrose, the wallflower apparently may not require sandy
soil, at least not in cultivation. Although the wallflower is endangered, it
has been doing fairly well on the Refuge, propagating on its own. After
the wallflower was planted in 1995, on dunes created in 1992 and 1993, it
was self-propagating until nonnative weeds began to invade. Other than
limited available habitat (wallflower seems to prefer north-facing slopes
at the Refuge), nonnative weeds pose the only apparent significant
threat to the wallflower.
Population Size and Status
In 1999, the population peaked at 11,567 individuals, the greatest
number of wallflowers ever counted on the Refuge (Figure 8). It is
possible that the increase in the number of mature plants was due to the
influence of El Nino during the winter of 1997-98. Seeds that
germinated that winter would have reached reproductive maturity in
1999 and germination or survival may have been higher than normal as
a result of increased rainfall, although this has not been studied.
Population survey results indicate that the total number of mature
plants is highly variable year to year. Because wallflower is a biennial
species, it would be expected to track yearly variation in weather and
other environmental parameters much more closely than a longer-lived
species. See Table 1 for a summary of trends for the three endangered
species.
$ -
The management goals and objectives for each individual unit of the
Refuge System vary. The Refuge System considers wildlife first when
deciding whether to allow a public use. Public use at an individual
0
1000
2000
3000
4000
5000
6000
Total Count
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
Year
Stamm Sardis PG&E East PG&E West
! .&

/
# +
Comprehensive Conservation Plan 35
Refuge and Resource Description
Refuge unit must be determined to be compatible with the specific
Refuge’s purpose. Public access to the Refuge is restricted based on the
sensitivity and limited distribution of the three endangered species.
Refer to the Compatibility Determinations in Appendix A. Historically,
the Antioch Dunes area and San Joaquin River were used for recreation
such as biking, walking, sunbathing, fishing, picnicking, and swimming,
while the upland areas were used for biking and walking.
The Refuge is fenced and was closed to the public in 1986 to protect the
endangered species and their habitat, a concern that arose as a result of
several incidents. Visitors using the Refuge prior to this time commonly
built illegal fires along the waterfront. On several occasions, the fires
escaped and threatened the survival of the three species by
indiscriminately burning surrounding habitat. In 1986, endangered
plants were trampled by hundreds of people as they flocked to the
Refuge to see a whale (nicknamed Humphrey) swim up the San Joaquin
River.
Although the Refuge is now closed to the public, volunteers help Refuge
staff by participating in endangered species counts, wallflower and
primrose plantings, picking up trash, and weeding. Occasional
interpretive tours are also given to various groups, such as the local
Sierra Club chapter or community college groups.
Despite boundary signs and perimeter fences around both the Sardis
and Stamm Units, unauthorized use of the Refuge continues.
Unauthorized visitors have been seen fishing at the Refuge and
evidence of numerous illegal camps have been found.

Several parties have easements on the Refuge including:
Contra Costa County has an easement for roadway slope and
drainage affecting the southern ten feet of the Refuge, which adjoin
Wilbur Avenue.
The City of Antioch has an easement and right-of-way for two
underground outfall sewer pipelines.
Georgia-Pacific has easements for roadway, water, gas, oil, and sewer
pipelines, and associated facilities.

+
Early Spanish explorers mentioned encountering Native American
villages in the Antioch area. According to Davidson (1907), the diary of
the 1772 expedition led by Lt. Fages and Padre Crespi refers to camping
at a Native American village thought to be near the site of present-day
Antioch. According to Padre Font, who accompanied Captain de Anza’s
1776 expedition, the Anza expedition visited a Native American village
on the site of Antioch. The village was “situated in the plain a little
before the sierra (translated from Spanish in Font’s diary to “oak ridge”)
toward which we were going, and so close to the water that from it to the
huts it could not have been a dozen steps” (Bolton 1933). Abella, Fages,
Font, and other explorers in the late 1700s and early 1800s mentioned
large numbers of deer, antelope, tule elk, and beaver. The abundance of
game, oak, and other foodstuffs, and proximity to water were
undoubtably key features attracting human settlers to the Refuge site.
As in many other Native American settlements, European contact in the
early 1800s caused a swift decline in the local Native American
community, primarily through introduced diseases.
36 Antioch Dunes National Wildife Refuge
Chapter 3
Settlement of the Antioch area by persons of European descent began in
1836 and continued in various forms of residence, agriculture, industry,
grazing, and recreation through the present day. Establishing the
Refuge in 1980 halted economic uses of the Refuge area including sand
mining and farming. Any evidence of earlier human activity in the
Refuge area has been obliterated by sand mining that began in the
1890s and continued through the twentieth century. The former sand
quarry remains as witness of human impact on the landscape.
Fragments of old bottles and ceramics were seen in a small portion of
the Stamm Unit in 1999. These fragments may indicate that a portion of
the sand quarry was back filled with household garbage. Further
investigation is warranted to determine if these items hold any historical
significance (Valentine pers. com. 2000).
'
-
The Refuge and surrounding lands have been used for industrial and
recreational purposes. Throughout the years, agricultural and
industrial use has been intense. Since the mid-1800s, the area has been
used as a dairy farm, vineyard, brick factory, sand mine, docking facility,
and a tavern site. Today, the Georgia-Pacific gypsum plant separates the
Stamm and Sardis Units. Because the area had been one of the few sites
for river access in the Antioch vicinity, it was historically a popular site
for fishing, swimming, and sunbathing.

The Service actively manages for the three endangered species using a
variety of measures that are outlined in this section. Habitat
management for the primrose, wallflower, and buckwheat is labor
intensive and includes annual surveys, nonnative weed control,
prescribed burning, importing sand, and revegetation. Emphasis is on
adaptive management; monitoring the effects of management actions
on endangered species populations and habitat health, and adjusting as
necessary.
Annual Surveys
Populations of the three endangered species are surveyed annually to
determine their status, prioritize management efforts, and analyze the
effects of various management prescriptions by specific Refuge MA
(Figures 3 and 4). Recent surveys have documented fairly healthy
wallflower and Lange’s populations, but have shown low rates of
primrose natural regeneration (See Figures 6, 7, and 8). Thus,
propagation efforts over the past few years have focused on the
primrose. The 2001 survey densities for the primrose, wallflower, and
Lange’s are shown in Figures 9 and 10.
Nonnative Weed Control
Although a number of weedy species are found at the Refuge, the recent
arrival of yellow starthistle has caused the most habitat degradation.
Various weed control methods have been used at the Refuge including
hand weeding, treating with herbicide, and prescribed burning. A series
of experimental plots were developed to test the response of nonnative
weeds to burning, flaming, broad-spectrum herbicide (Roundup®),
grass-specific herbicide (Poast®), pre-emergent herbicide, a more
specific herbicide (Transline®), and mowing. Early results indicate that
HARDPAN #2
SCARIFIED
TRIANGLE
HARDPAN #1
NORTH
EAST
HARDPAN #3
SOUTH OF PATH
EAST
PLATEAU
RESTORED VINEYARD
HARDPAN #4
PLATEAU
1995
DUNES
ACCESS ROAD
ENTRY
CAR BODY
HARDPAN SLOPE
RIVER SLOPE
TRIANGLE
SECTION
TO OAK
BLOWOUT
VINEYARD
PLATEAU
RIVER
HARDPAN #2
SCARIFIED
TRIANGLE
HARDPAN #1
NORTH
EAST
HARDPAN #3
SOUTH OF PATH
EAST
PLATEAU
RESTORED VINEYARD
HARDPAN #4
PLATEAU
1995
DUNES
ACCESS ROAD
ENTRY
CAR BODY
HARDPAN SLOPE
RIVER SLOPE
TRIANGLE
SECTION
TO OAK
BLOWOUT
VINEYARD
PLATEAU
RIVER
HARDPAN #2
SCARIFIED
TRIANGLE
HARDPAN #1
NORTH
EAST
HARDPAN #3
SOUTH OF PATH
EAST
PLATEAU
RESTORED VINEYARD
HARDPAN #4
PLATEAU
1995
DUNES
ACCESS ROAD
ENTRY
CAR BODY
HARDPAN SLOPE
RIVER SLOPE
TRIANGLE
SECTION
TO OAK
BLOWOUT
VINEYARD
PLATEAU
RIVER
0
1 - 25
26 - 100
101 - 250
> 250
0
1 - 25
26 - 80
81 - 120
> 120
0
1 - 10
11 - 20
21 - 80
>80
Contra Costa Wallflower
Lange's Metalmark Butterfly
Antioch Dunes Evening Primrose
500 0 500 1,000 Feet
CA/NV Refuge Planning Office - May 2002 I
Figure 9. Stamm Unit Densities (no./acre) Based on 2001 Counts - Antioch Dunes National Wildlife Refuge

PIT FLOOR
WEST
SOUTH OF
CABLES
SOUTH PLATEAU
1995
1992
DUNES
EAST OF
CORRIDOR
PLATEAU
1995
DUNES
1993
DUNES
RIVER FLAT
WEST OF
CORRIDOR
PLATEAU
SOUTH
SLOPE
WEST SLOPE
EUCALYPTUS
HILL
CORRIDOR
NORTH OF
TOWER
ACCESS
ROAD
SLOPE
1992/1993
NEW DUNES
RIVER
CREST
DOMTAR
TOWER
NORTHWEST
SLOPE
SOUTHWEST
CORNER
SLOPE
SMALL INNER HILL
NORTH AND
EAST OF TOWER
KEMWATER
RIVER
CREST
TRIANGLE
NORTH
SLOPE
EAST
SLOPE
NORTH SLOPE (PG&E)
PG&E Land Sardis Unit PG&E Land
PIT FLOOR
WEST
SOUTH OF
CABLES
SOUTH PLATEAU
1995
1992
DUNES
EAST OF
CORRIDOR
PLATEAU
1995
DUNES
1993
DUNES
RIVER FLAT
WEST OF
CORRIDOR
PLATEAU
SOUTH
SLOPE
WEST SLOPE
EUCALYPTUS
HILL
CORRIDOR
NORTH OF
TOWER
ACCESS
ROAD
SLOPE
1992/1993
NEW DUNES
RIVER
CREST
DOMTAR
TOWER
NORTHWEST
SLOPE
SOUTHWEST
CORNER
SLOPE
SMALL INNER HILL
NORTH AND
EAST OF TOWER
KEMWATER
RIVER
CREST
TRIANGLE
NORTH
SLOPE
EAST
SLOPE
NORTH SLOPE (PG&E)
PG&E Land Sardis Unit PG&E Land
PIT FLOOR
WEST
SOUTH OF
CABLES
SOUTH PLATEAU
1995
1992
DUNES
EAST OF
CORRIDOR
PLATEAU
1995
DUNES
1993
DUNES
RIVER FLAT
WEST OF
CORRIDOR
PLATEAU
SOUTH
SLOPE
WEST SLOPE
EUCALYPTUS
HILL
CORRIDOR
NORTH OF
TOWER
ACCESS
ROAD
SLOPE
1992/1993
NEW DUNES
RIVER
CREST
DOMTAR
TOWER
NORTHWEST
SLOPE
SOUTHWEST
CORNER
SLOPE
SMALL INNER HILL
NORTH AND
EAST OF TOWER
KEMWATER
RIVER
CREST
TRIANGLE
NORTH
SLOPE
EAST
SLOPE
NORTH SLOPE (PG&E)
PG&E Land Sardis Unit PG&E Land
0
<25
26 - 100
101 - 250
> 250
0
<25
25 - 80
81- 120
> 120
0
<10
10 - 20
21 - 80
>80
Contra Costa
Wallflower
Lange's Metalmark
Butterfly
Antioch Dunes
Evening Primrose
500 0 500 Feet CA/NV Refuge Planning Office - May 2002 I
Figure 10. Sardis Unit and PG&E Property Densities (no./acre) Based on 2001 Counts - Antioch Dunes National Wildlife Refuge
38
Comprehensive Conservation Plan 39
Refuge and Resource Description
nonnative weeds do respond to these techniques to varying degrees.
Poast®, a grass-specific herbicide, has been effective in controlling
Bromus. Except for flaming, other treatments (including Transline®)
have also been effective at controlling Bromus. Treating starthistle with
Transline® provided excellent control. Starthistle also responded to
flaming before seed set and responded to burning and somewhat to
mowing. Because Transline® also killed buckwheat (Rusmore 1999), it
cannot be used in areas with buckwheat stands.
In 1997, the Service prepared an EA for the Prescribed Burn Program
for the Refuge (Service 1997b). The Refuge then conducted its first
prescribed burn in 1997 and burned about 12 acres total, divided among
the Triangle MA and a portion of the Restored Vineyard MA of the
Stamm Unit, and the South Plateau MA of the Sardis Unit, areas
dominated by nonnative weeds (Figures 3 and 4). The goal was to burn
these areas for three consecutive years to kill the nonnative weeds and
reduce their seed bank. Persistent starthistle was spot treated with
Roundup®. As of 1999, these areas had been burned for three
consecutive years and were recently replanted with native vegetation.
Two other Refuge MAs, Hardpan 1 MA and the remainder of the
Vineyard MA, were added to the burn program in 1999 and were burned
for three consecutive years.
The burned areas showed promising though mixed results. Primrose
and other native plants within the Triangle MA of the Stamm Unit
responded positively. Starthistle has been effectively controlled through
three years of prescribed burning. Unfortunately, other nonnative
weeds like filaree and vetch moved into the burned areas quickly
(Rusmore 1999). Vetch is currently being controlled with herbicide.
Continuing research efforts in nonnative weed control will enable the
Refuge to determine the most effective method to control nonnative
weeds. Methods that are effective will continue to be implemented
(Fernandez 1997, Rusmore 1999, Loredo pers. com. 2000). The Refuge
will continue to burn areas that are dominated by nonnative weeds
(Fernandez 1997), unless other methods are determined effective. Only
areas that do not support many Lange’s will be considered for the
program. In addition, small firebreaks will be constructed around any
individual primrose or wallflower in the proposed burn areas. This will
minimize effects to endangered species (Appendix J).
Hand weeding and mowing also continue to be important tools in
controlling weeds to promote native plant growth, particularly the
primrose. Each of the endangered species on the Refuge are dependent
on an open sand dune environment. To stabilize and increase their
populations, management actions must continue to recreate this
environment to the extent possible.
Importing Sand
New dunes were created by the Service, with the help of PG&E, by
using imported sand. The first major dune restoration effort began in
1991. To create new dunes on the Refuge, PG&E donated, hauled, and
contoured native riverine sand from a stockpile at a power plant
formerly owned by PG&E located about one mile from the eastern
boundary of the Refuge. The dunes were contoured to mimic the
historic dunes and were then planted with nursery-grown endangered
and native plants endemic to the Refuge. Nonnative weeds were hand-pulled
and sprayed with herbicide to prevent encroachment on the
40 Antioch Dunes National Wildife Refuge
Chapter 3
Constructing dunes using existing sand.
USFWS Photo
newly restored site. The dune restoration was continued for an
additional year. Three dunes were created in the Sardis Unit and one in
the Stamm Unit.
Overall, about 7,000 cubic yards of sand (Morton pers.
com. 2000) were imported and thousands of buckwheat,
primrose, and wallflower were established on the new
dunes in an attempt to create an open sand dune
environment similar to conditions prior to sand mining.
Buckwheat and Lange’s have persisted on these created
dunes, however, primrose and wallflower are found only
in small numbers on these dunes, if at all. As has
happened on most of the Refuge, nonnative weeds have
heavily colonized the restored dunes, and are probably
outcompeting the endangered species (Fernandez 1997).
Dunes created during this project can be identified in
Figures 3 and 4 as 1992 Dunes, 1993 Dunes, and 1995
Dunes. Though these dunes were all created in 1991 and
1992, they are named for the year they were planted. In
addition, there have been several recent dune
construction projects on the Stamm Unit that have used
existing substrate material. Using heavy equipment,
existing sand was pushed up to form steep sided dune formations. In
the fall of 1999, three dunes were recontoured in the Vineyard MA using
a grant from Chevron Corporation. In February of 2000 an additional
dune was constructed in the Northeast MA as part of a City of Antioch
mitigation project. Caltrans provided labor for this project and
constructed a fourth dune in the Vineyard MA.
Revegetation
The Service has propagated primrose, wallflower, and buckwheat in the
past, and will add other sensitive native species to its propagation efforts
in the future. During seed collection, no more than 5 percent of the
seeds are collected from Refuge plants for propagation. These seeds are
grown in a nursery during the fall for planting on the Refuge in the
winter. Plants were grown in either the Refuge greenhouse, which had
limited space, or contracted out to commercial nurseries. In 2000, the
Service completed construction of an additional greenhouse to
accommodate an increased quantity of endangered plant propagation.
In the 1999-2000 season, the Service propagated and planted 835
primrose to augment the wild population (Loredo pers. com. 2000).
Firebreaks
The City of Antioch requires the Service to maintain a firebreak
between the Refuge and the adjacent railroad tracks. The Refuge has
tried scraping and discing to remove potentially flammable materials.
Discing resulted in more nonnative weeds than had previously existed.
Scraping (removing the top 1 to 2 inches of soil by scraping the soil
surface with heavy equipment, such as a bulldozer with a blade),
however, seemed to open up more habitat and allowed endangered
species to resprout in greater numbers than prior to scraping (First
Technical Panel 1999). The Service also established firebreaks within
the Refuge to contain prescribed burns on the Refuge. Again, scraping
proved to be more beneficial to endangered plants than discing (First
Technical Panel 1999).
Comprehensive Conservation Plan 41
Chapter 4 - Problems and
Opportunities

The Refuge was established to protect three endangered species.
Maintaining sustainable populations of the three endangered species in
a small area, while providing habitat for other plants and animals known
to inhabit the dune ecosystem, presents a demanding challenge. A web
of many interrelated and cumulative factors contribute to the problems
of maintaining self-sustaining populations of the three endangered
species.
Many factors, including urban development, habitat fragmentation, and
sand mining, have contributed to the decline of the species the Refuge
was created to protect. Although numbers of the Lange’s and wallflower
have fluctuated over the past 10 years (Figures 6, 7, and 8), their popula-tions
overall have increased. However, primrose numbers have declined
in the last 10 years. There were 5,800 mature primrose in 1984, and only
963 mature primrose in 1996, a decrease of 83 percent. The main prob-lem
affecting the primrose and wallflower is nonnative weeds. Other
potential problems include lack of suitable substrate, lack of insect
pollinators, inadequate land base, and predation.
Planning staff, the technical panel, and other key contacts identified
problems plaguing the Refuge’s endangered species and other re-sources.
The problems are described below and are grouped into
general categories. Although the divisions can seem arbitrary, catego-rizing
the problems make them easier to understand.
Dune Habitat
Loss of habitat, primarily through sand mining and industrial develop-ment,
was a key factor in the decline of the endangered plants on the
Refuge. Early industrialization and agricultural conversion (vineyards
and grazing) contributed to the destruction of habitat. The dune habitat
has been altered by sand mining which leveled the mined areas. His-torical
records corroborate that the dunes probably consisted of upland
vegetation with a few patches of sandy habitat that formed in eroded
portions on the river side of the dunes. Since the former two-mile dune
system has been reduced to the narrow extent of the Refuge, there is no
longer enough riverfront property to sustain endangered species
habitat at historic levels (Arnold et al. 1983). Problems related to dune
habitat include:
■ Lack of ecosystem function,
■ Lack of native plant diversity,
■ Loss of habitat,
42 Antioch Dunes National Wildife Refuge
Chapter 4
■ Fragmentation and associated problems (i.e. decreased genetic
diversity), and
■ Decreasing populations and species diversity of native insects,
reptiles, mammals, and birds.
Nonnative Weeds
The major threat to the primrose, wallflower, and other native species,
are nonnative weeds such as yellow starthistle and ripgut brome. Non-native
weeds lead to lower germination and seedling survival rates and
have been identified as the leading problem for endangered species and
the dune ecosystem habitat at Antioch Dunes.
The problems caused by, and associated with, nonnative weeds are
complex and interrelated. Nonnative weeds not only outcompete natives
for sunlight, moisture, space, and nutrients, but they also stabilize what
little remains of the dunes. Primrose evolved on shifting, windblown
riverine sand dunes and appears to thrive with a certain amount of
disturbance. Unfortunately, the soil stabilization provided by nonnative
weeds prevents the dunes from shifting, increasing competition for
resources and posing a significant problem to those species requiring
open sandy substrate for survival.
In general, nonnative weeds affect the primrose and wallflower in a
similar manner. Nonnative weeds can affect Lange’s indirectly by
affecting the buckwheat. Nonnative weeds on the Refuge form dense
stands, areas Lange’s avoid. Lange’s use the native buckwheat for egg-laying
sites and nectar sources. Without a sufficient number of buck-wheat
plants at the appropriate density, the butterfly population will not
be supported.
The first technical panel (1999) hypothesized that excessive nitrogen in
the soils might limit the reproductive success of the primrose, wall-flower,
and buckwheat. Increased nitrogen can promote nonnative
weeds, while too little nitrogen can inhibit primrose, wallflower, and
buckwheat reproduction. Factors that contribute to increased nitrogen
include accumulated biomass, herbicide application (herbicides can
increase the nitrogen load in the soil), and prescribed burning. In 1999,
a soil survey conducted at the Refuge investigated differences in soil
conditions between areas that supported healthy populations of prim-rose,
wallflower, and buckwheat (population sites) versus areas that did
not support these species but instead were dominated by nonnative
weeds (control sites) (Jones and Stokes 2000). The survey found no
significant difference in soil nitrogen levels between the two types of
sites. Instead, soil from population sites was found to be significantly
lower in percent of organic matter and phosphorus compared to soil
from control sites. Thus, the three species are adapted to less fertile,
rapidly permeable soils, presumably where they can outcompete nonna-tive
weeds.
Nonnative weeds also lead to lower native plant diversity. Decreased
plant diversity leads to lower insect diversity. Maffei (1997) correlated
weeds stabilizing sand with a decline in insect diversity. He observed 30
species of velvet ants in 1995 and only six in 1997. Similar declines were
seen for other insects. Lower insect diversity can ultimately lead to a
decrease in pollinators, which can lead to a decrease in the endangered
species populations (Second Technical Panel 1999).
Comprehensive Conservation Plan 43
Problems and Opportunities
Disturbance
Primrose, wallflower, and buckwheat, have different tolerances to
disturbance. Primrose requires some level of disturbance and responds
well to prescribed burns, firebreak scraping, and weed pulling in close
vicinity to a plant. Wallflower prefers steep north-facing slopes which
receive natural disturbance through erosion. Lange’s and buckwheat do
respond favorably to disturbance. Lange’s can be immediately nega-tively
impacted by disturbances such as burns and scraping, and healthy
buckwheat populations can be found in areas with little disturbance.
However, Lange’s prefers buckwheat in various successional stages and
some disturbance may be necessary to provide this range. However,
when planning disturbance of Lange’s habitat, the short-term negative
effects to Lange’s must be considered. Disturbance will not be con-ducted
in areas supporting substantial numbers of Lange’s, where the
short-term negative effects may outweigh the long-term benefit. The
varying tolerances and disturbance needs of the three species pose
management problems.
Predation
Several predation problems were identified for the three endangered
species within the approved Refuge boundaries.
Mammals
Mammals have been known to eat primrose (Second Technical Panel
1999). Although the specific predator has not yet been identified, it is
presumed to be a subterranean animal, probably a rodent. This preda-tor
eats roots, leaving primrose severed at the tap root, killing the plant.
There has also been evidence of mammals eating the above ground
portions of the plant (Loredo pers. com. 2000a).
Insects
Powell (1999) has identified three insect predators for the primrose.
One is the Mompha murtfeldtella, a moth that feeds on growing tips but
does not seem to limit the primrose’s ability to be self-sustaining.
Another moth, Mompha eloisella, grazes in the interior of primrose
stems, but also does not have a major effect (Powell 1992). However,
Altica sp., a leaf eating beetle, reduces plants to skeletons in early
summer, and does present a potential threat to the sustainability of the
primrose population.
The wallflower is also a host plant for three herbivorous insects,
Chalceopla simpliciella, a moth that feeds on immature wallflower seeds
and later is believed to feed on new wallflower leaves, Calcus sp., a moth
that lays eggs on the wallflower, and Plutella xylostella, an external
feeder whose larvae have been found on the wallflower (Powell pers.
com. 1999).
Problems Relating to Viable Seed Production
The lack of pollinators for the primrose has been discussed in at least
two papers, Pavlik et al. (1993), and Pavlik and Manning (1993), and at a
technical panel (1999). Although seed production in the primrose is
high, indicating that the primrose is being adequately pollinated, a lack
of pollinators may contribute somewhat to its decline in the future.
Primrose are primarily pollinated by bees. Other species of primrose
44 Antioch Dunes National Wildife Refuge
Chapter 4
have been known to be pollinated by a hawkmoth, although there are no
documented cases of the Antioch Dunes evening primrose being polli-nated
this way.
Factors related to the lack of viable seed production are complex. Low
insect diversity is a contributing factor to the decrease in pollination.
Low native plant diversity is a likely cause of low insect diversity and a
decrease in pollinators. Greene (1995) and Thompson (1997) have also
conducted research into the effect of low plant genetic diversity on seed
viability and have found that the lack of genetic variability in the prim-rose
likely leads to a decrease in seed viability.
Wildlife
Historically, the Refuge was home to the western toad, western rattle-snake,
coast horned lizard, western fence lizard, side-blotched lizard,
California legless lizard, glossy snake, racer, and gopher snake. How-ever,
few reptiles have been seen in recent years. For example, the last
horned lizard was seen in 1933. The lack of reptile diversity on the
Refuge could possibly be attributed to the lack of native vegetation and
loose sand, and destruction of habitat throughout the area. Further-more,
the range of the dunes has become limited and fragmented after a
long history of extreme disturbance.
Human Disturbance
At the first technical panel meeting (1999), human disturbance, such as
wildfire, foot, bike, and motorcycle trespassers, was identified as a
problem on the Refuge. Disturbance destroys plants growing in the
immediate area of the disturbance. Even habitat management can
result in individual trampling. However, the primrose repopulates the
area quickly if the disturbance is not too frequent or repeated. It is
possible that some walking-related disturbance may be beneficial, even
necessary, to the primrose and other plant species native to dune sys-tems
that are adapted to natural disturbances such as strong winds,
shifting dunes, or river erosion.
However, uncontrolled human presence can cause undesirable impacts
to the Refuge, such as litter, trampling threatened and endangered
species, wildfires, and vandalism. A lack of staff presence at the Refuge
and insufficient law enforcement patrols result in more incidences of
trespassing and vandalism.
Wildfires
All fires not classified as prescribed fires are wildfires. Unlike pre-scribed
burns, wildfires are uncontrolled. Therefore, wildfires can be
extremely destructive to endangered species. Lange’s, in particular,
takes many years to recover from wildfires since fires tend to kill all
larvae or destroy eggs (depending on the timing). Also, areas support-ing
healthy populations of endangered plants could be damaged by
wildfires. When planning prescribed burns, on the other hand, areas are
carefully chosen to minimize effects to endangered species.
Wildfires set by trespassers or escaping from adjacent properties have
negatively affected the endangered species and other native habitat on
the Refuge. For example, Refuge Officer Barry Tarbet and Service fire
crew leader Chuck Berner conducted a site visit to investigate the cause
and origin of the May 1999 wildfire. They surveyed the entire riverfront
Comprehensive Conservation Plan 45
Problems and Opportunities
and fire boundary and found evidence that the wildfire was started at
the river by a trespasser’s campfire. The 10-acre wildfire spread
through the northeastern portion of the Stamm Unit, burning the entire
Blowout MA of the Refuge (Figure 3). The Blowout MA had previously
provided excellent Lange’s habitat. Because the Lange’s spend their
larval phase in the lower leaves of the buckwheat, it is likely that the
entire population of Lange’s throughout the burn area perished. Many

Object Description

Rating
Title	Antioch Dunes National Wildlife Refuge Comprehensive Conservation Plan
Description	index.cpd
FWS Resource Links	http://library.fws.gov
Subject	Document Wildlife refuges Planning
Location	Region 8 California
FWS Site	ANTIOCH DUNES NATIONAL WILDLIFE REFUGE
Publisher	U.S. Fish and Wildlife Service
Date of Original	August 2002
Type	Text
Format	PDF
Source	NCTC Conservation Library
Rights	Public Domain
File Size	423 Bytes
Original Format	Document
Full Resolution File Size	423 Bytes
Tag	Library-Source-CCPs
Date created	2013-03-06

Description

Title	Antioch Dunes National Wildlife Refuge Comprehensive Conservation Plan
Description	antiochdunes_final.pdf
FWS Resource Links	http://library.fws.gov
Subject	Document Wildlife refuges
Location	Region 8 California
FWS Site	ANTIOCH DUNES NATIONAL WILDLIFE REFUGE
Publisher	U.S. Fish and Wildlife Service
Date of Original	August 2002
Type	Text
Format	PDF
Source	NCTC Conservation Library
Rights	Public Domain
File Size	16516256 Bytes
Original Format	Document
Length	86
Full Resolution File Size	16516256 Bytes
Transcript	U.S. Fish & Wildlife Service Antioch Dunes National Wildlife Refuge Comprehensive Conservation Plan Vision Statement “Our vision is that endangered species management will be incorporated into the overall management of the riverine sand dune ecosystem. Using management actions that mimic natural processes, the Refuge will support self-sustaining populations of Lange’s, wallflower, primrose, and other native species.” “Through high quality interpretive and environmental education programs, the public will have opportunities to visit and gain an appreciation for the unique ecosys-tem of the Refuge and an understanding of endan-gered species protection and the role of the Refuge System in recovering endangered species.” U. S. Fish and Wildlife Service California/Nevada Refuge Planning Office 2800 Cottage Way, Room W-1916 Sacramento, CA 95825 August 2002 Antioch Dunes National Wildlife Refuge i Table of Contents Acronymns and Definitions ..................................................................................................................................... iii List of Selected Scientific Names ............................................................................................................................ iv Chapter 1 - Introduction ........................................................................................................................................... 1 Introduction ................................................................................................................................................. 1 Purpose and Need for the Plan ................................................................................................................. 1 The U.S. Fish and Wildlife Service and the National Wildlife Refuge System ................................ 2 U.S. Fish and Wildlife Service Responsibilities ....................................................................................... 2 The National Wildlife Refuge System ....................................................................................................... 2 Legal and Policy Guidance ........................................................................................................................... 2 The Antioch Dunes National Wildlife Refuge ........................................................................................ 3 Location ......................................................................................................................................................... 3 Land Ownership........................................................................................................................................... 6 Partnerships ................................................................................................................................................. 6 Refuge Setting ............................................................................................................................................. 6 Refuge History ............................................................................................................................................. 7 Refuge Purpose .......................................................................................................................................... 10 Related Projects and Studies in the Area ............................................................................................. 10 U.S. Fish and Wildlife Service .................................................................................................................. 10 The Recovery Plan for the Primrose, Wallflower, and Lange’s ....................................................... 10 Other Agencies ........................................................................................................................................... 11 Brannan Island State Recreation Area .............................................................................................. 11 The Regional Parks Botanic Garden at Tilden Regional Park ........................................................ 11 Montezuma Wetlands ........................................................................................................................... 11 CALFED............................................................................................................................................... 12 Chapter 2 - The Planning Process .......................................................................................................................... 13 The Planning Process ............................................................................................................................... 13 Issues ......................................................................................................................................................... 14 Issues Identified by the Public ................................................................................................................. 14 Issues Identified by Refuge Staff, Panel of Experts, and Other Agencies ......................................... 15 Chapter 3 - Refuge and Resource Description .................................................................................................... 17 Ecoregion Setting ..................................................................................................................................... 17 Geographic and Physical Setting ............................................................................................................ 17 Wilderness ................................................................................................................................................. 18 Management Area Designations ............................................................................................................. 18 Topography ................................................................................................................................................ 18 Geology ....................................................................................................................................................... 18 Soils............................................................................................................................................................. 21 Climate ....................................................................................................................................................... 21 Air Quality ................................................................................................................................................. 21 Contaminants ............................................................................................................................................ 22 Hydrology .................................................................................................................................................. 23 Water Supply ............................................................................................................................................. 23 Vegetation ................................................................................................................................................... 23 Wildlife ....................................................................................................................................................... 26 Fish ............................................................................................................................................................. 26 Invertebrates ............................................................................................................................................ 26 ii Endangered Species ................................................................................................................................ 27 Lange’s Metalmark Butterfly - Apodemia mormo langei .................................................................... 28 Background ........................................................................................................................................... 28 Population Size and Status ................................................................................................................... 29 Antioch Dunes Evening Primrose, Oenothera deltoides spp. howellii ............................................... 30 Background ........................................................................................................................................... 30 Population Size and Status ................................................................................................................... 32 Contra Costa Wallflower, Erysimum capitatum spp. angustatum ....................................................... 32 Background ........................................................................................................................................... 32 Population Size and Status ................................................................................................................... 34 Public Use ................................................................................................................................................. 34 Easements ................................................................................................................................................. 35 Cultural Resources .................................................................................................................................. 35 Land Use ................................................................................................................................................... 36 Current Management Practices ............................................................................................................. 36 Annual Surveys .......................................................................................................................................... 36 Nonnative Weed Control ............................................................................................................................ 36 Importing Sand .......................................................................................................................................... 39 Revegetation ............................................................................................................................................... 40 Firebreaks .................................................................................................................................................. 40 Chapter 4 - Problems and Opportunities .............................................................................................................. 41 Problems .................................................................................................................................................... 41 Dune Habitat .............................................................................................................................................. 41 Nonnative Weeds ....................................................................................................................................... 42 Disturbance ................................................................................................................................................ 43 Predation ..................................................................................................................................................... 43 Mammals ............................................................................................................................................... 43 Insects .................................................................................................................................................... 43 Problems Relating to Viable Seed Production ....................................................................................... 43 Wildlife ........................................................................................................................................................ 44 Human Disturbance .................................................................................................................................. 44 Wildfires ...................................................................................................................................................... 44 External Factors ........................................................................................................................................ 45 Lack of Information .................................................................................................................................. 45 Opportunities ............................................................................................................................................ 46 Chapter 5 - Refuge Vision, Goals, and Objectives ................................................................................................ 47 Vision Statement ....................................................................................................................................... 47 Management Philosophy .......................................................................................................................... 47 Goals ........................................................................................................................................................... 47 Endangered Species ................................................................................................................................ 48 Ecosystem Protection, Restoration, and Management....................................................................... 53 Public Use ................................................................................................................................................. 60 Chapter 6 - Funding and Personnel ....................................................................................................................... 65 Chapter 7 - Monitoring and Evaluation ................................................................................................................ 67 Chapter 8 - Compliance Requirements ................................................................................................................. 71 References ................................................................................................................................................................ 75 iii List of Figures Figure 1. Regional Map .................................................................................................................................... 5 Figure 2. Refuge Map ....................................................................................................................................... 6 Figure 3. Management Areas with Acreages - Stamm Unit ...................................................................... 19 Figure 4. Management Areas with Acreages - Sardis Unit........................................................................ 20 Figure 5. Three Main Habitat Types on the Refuge ................................................................................... 24 Figure 6. Lange’s Metalmark Butterfly Peak Count Survey Results....................................................... 30 Figure 7. Antioch Dunes Evening Primrose Survey Results .................................................................... 33 Figure 8. Contra Costa Wallflower Survey Results ..................................................................................... 34 Figure 9. Stamm Unit Densities..................................................................................................................... 37 Figure 10. Sardis Unit Densities .................................................................................................................... 38 Figure 11. Proposed Management for Antioch Dunes National Wildlife Refuge .................................. 55 List of Tables Table 1. General Trends for Refuge Endangered Species.......................................................................... 31 Table 2. Estimated Initial Capital Outlay to Implement the CCP ............................................................ 66 Table 3. Estimated Annual Cost to Implement the CCP ............................................................................ 66 Table 4. Monitoring Methods .......................................................................................................................... 68 List of Appendices Appendix A - Compatibility Determinations Appendix B - Technical Panel Appendix C - Environmental Assessment Appendix D - Response to Comments Appendix E - Wilderness Review Appendix F - Plant List Appendix G - Bird List Appendix H - Fish List Appendix I - Insect List Appendix J - Fire Management Plan Appendix K - Glossary Acronyms and Definitions U.S. Fish and Wildlife Service Service Antioch Dunes National Wildlife Refuge Refuge National Wildlife Refuge refuge Sacramento/San Joaquin River Delta Delta Antioch Dunes evening primrose primrose Contra Costa wallflower wallflower Lange’s metalmark butterfly Lange’s California Department of Transportation Caltrans California Department of Parks and Recreation DPR California Native Plant Society CNPS Pacific Gas and Electric Company PG&E University of California UC Environmental Assessment EA National Wildlife Refuge System Refuge System Comprehensive Conservation Plan CCP Naked-stemmed buckwheat buckwheat Global positioning system GPS State Recreation Area SRA Management Area MA Bay Area Air Quality Management District BAAQMD iv List of Selected Scientific Names (also see appendices F, G, H and I) Oenothera deltoides ssp. howellii (e) Antioch Dunes evening primrose Erysimum capitatum ssp. angustatum (e) Contra Costa wallflower Apodemia mormo langei (e) Lange’s metalmark butterfly Eriogonum nudum var. auriculatum naked-stemmed buckwheat Centaurea solstitialis yellow starthistle Bromus diandrus ripgut broome Vicia villosa ssp. varia winter vetch Vicia sativa ssp. nigra common vetch Lepidium latifolium pepperweed Cortaderia sellowiana pampas grass Arundo donax giant reed Robinia psuedoacacia black locust Nerium oleander oleander Ailanthus altissima tree of heaven Croton californicus croton (e) Federally listed endangered species Comprehensive Conservation Plan 1 Chapter 1 - Introduction Introduction The Antioch Dunes National Wildlife Refuge (Refuge) is the first and only wildlife refuge in the country established to protect endangered plants and insects. Created in 1980 by the U.S. Fish and Wildlife Service (Service), this riverside refuge provides protection and critical habitat for three endangered species: Lange’s metalmark butterfly (Apodemia mormo langei) (Lange’s), Contra Costa wallflower (Erysimum capitatum angustatum) (wallflower), and Antioch Dunes evening primrose (Oenothera deltoides howellii) (primrose). The Refuge, 55 acres of former dunes, in addition to the adjacent 12 acres of Pacific Gas and Electric Company (PG&E) land, is an isolated patch of what was once a larger dune system that hosted a unique assemblage of plants, insects, and reptiles. A major effort is currently underway to restore and improve dune habitat on the Refuge. The Refuge is managed by staff based in the San Francisco Bay National Wildlife Refuge Complex office in Fremont, California. Purpose and Need for the Plan The Service prepared this Comprehensive Conservation Plan (CCP) to guide wildlife and other natural resource management, including public use, on the Refuge for the next 15 years. The CCP is flexible; it will be revised periodically to ensure that its goals, objectives, implementation strategies, and timetables are still valid and appropriate. Major revisions will require public involvement and National Environmental Policy Act (NEPA) review, if needed. The CCP will: � Provide a clear statement of direction for Refuge management for the next 15 years. � Provide a clear vision of the desired future conditions of the Refuge. � Provide the public with an understanding of the reasons for management actions on the Refuge. � Ensure that Refuge management reflects the mission, policies, and goals of the National Wildlife Refuge System (Refuge System). � Ensure the compatibility of current and future uses of the Refuge. Antioch Dunes Evening primrose and Contra Costa wallflower USFWS Photo 2 Antioch Dunes National Wildife Refuge Chapter 1 � Provide long-term continuity of Refuge management. � Provide a basis for operation, maintenance, and development budget requests. The U.S. Fish and Wildlife Service and the National Wildlife Refuge System U.S. Fish and Wildlife Service Responsibilities The Service is the primary Federal agency responsible for conserving and enhancing the Nation’s fish and wildlife populations and their habitats. Although this responsibility is shared with other Federal, State, Tribal, local, and private entities, the Service has specific responsibilities for migratory birds, threatened and endangered species, anadromous fish, and certain marine mammals. The Service has similar responsibilities for the lands and waters it administers to support the conservation and enhancement of fish and wildlife. The National Wildlife Refuge System The Refuge System is the world’s largest collection of lands specifically managed for fish and wildlife conservation. Unlike other Federal lands that are managed under a multiple-use mandate (e.g., lands administered by the U.S. Bureau of Land Management and the Forest Service), the Refuge System is managed for the benefit of fish, wildlife, plants, and their habitats. The Service manages the 95 million-acre National Wildlife Refuge System which encompasses nearly 540 national wildlife refuges, thousands of small wetlands, and other special management areas. The majority of refuge lands (approximately 77 million acres) are in Alaska. The remaining acres are spread across the other 49 states and several island territories. The mission of the Refuge System is “to administer a national network of lands and waters for the conservation, management and, where appropriate, restoration of the fish, wildlife, plant resources, and their habitats within the United States for the benefit of present and future generations of Americans” (16 USC 668dd et seq.). The goals of the Refuge System are to: � Preserve, restore, and enhance in their natural ecosystems (when practicable) all species of animals and plants that are endangered or threatened with becoming endangered; � Perpetuate the migratory bird resource; � Preserve a natural diversity and abundance of fauna and flora on refuge lands; and � Provide an understanding and appreciation of fish and wildlife ecology, the human role in the environment, and provide refuge visitors with high-quality, safe, wholesome, and enjoyable wildlife-dependent recreational experiences oriented toward wildlife to the extent these activities are compatible with the purposes for which the refuge was established. Legal and Policy Guidance National Wildlife Refuges are guided by the mission and goals of the Refuge System, purposes of the Refuge, Service policy, laws, and inter-national treaties. Relevant guidance includes the National Wildlife Comprehensive Conservation Plan 3 Introduction Refuge System Administration Act of 1966, as amended by the National Wildlife Refuge System Improvement Act of 1997 (Improvement Act), the Refuge Recreation Act of 1962, and selected portions of the Code of Federal Regulations and the Fish and Wildlife Service Manual. The Refuge Recreation Act of 1962, as amended, authorized the Secretary of the Interior to administer refuges, hatcheries, and other conservation areas for recreational use when such uses did not interfere with the area’s primary purpose. The National Wildlife Refuge System Administration Act of 1966, as amended by the Improvement Act, created a mission statement for the Refuge System; established six priority public uses (hunting, fishing, wildlife observation and photography, environmental education and interpretation); emphasized conserving and enhancing the quality and diversity of fish and wildlife habitat; stressed the importance of partnerships with Federal and State agencies, Tribes, organizations, industry, and the general public; mandated public involvement in decisions concerning the acquisition and management of refuges; and required, prior to acquisition of new refuge lands, identification of existing compatible wildlife-dependent uses that would be permitted to continue on an interim basis pending completion of comprehensive conservation planning. The Improvement Act establishes the responsibilities of the Secretary of the Interior for managing and protecting the Refuge System; requires a CCP for each refuge by the year 2012; provides guidelines and directives for the administration and management of all areas in the Refuge System, including wildlife refuges, areas for the protection and conservation of fish and wildlife threatened with extinction, wildlife ranges, game ranges, wildlife management areas, or waterfowl production areas. The Improvement Act also establishes a formal process for determining compatibility of uses. Before any uses, including priority public uses, are allowed on refuges, Federal law requires that they be formally determined “compatible.” A compatible use is defined as a use that, in the sound professional judgement of the refuge manager, will not materially interfere with or detract from the fulfillment of the refuge purposes. Sound professional judgement is defined as a finding, determination, or decision that is consistent with the principles of sound fish and wildlife management and administration, available science and resources (funding, personnel, facilities, and other infrastructure), and applicable laws. The Service strives to provide priority public uses when compatible. If financial resources are not available to design, operate, and maintain a priority use, the Refuge manager will take reasonable steps to obtain outside assistance from the State and other conservation interests. The Refuge has completed compatibility determinations for environmental education, interpretation, wildlife observation and photography, and research (Appendix A). The Antioch Dunes National Wildlife Refuge Location The Refuge is adjacent to the City of Antioch, Contra Costa County, California along the south shore of the San Joaquin River in an area that 4 Antioch Dunes National Wildife Refuge Chapter 1 was once part of an expanse of riverine sand dunes (Figure 1). The Refuge consists of two disjunct parcels (Figure 2). The westernmost unit, the 41-acre Stamm Unit, is bordered to the west by Fulton Shipyard; to the east by the Georgia-Pacific gypsum plant; to the south by Fulton Shipyard Road, Burlington Northern/Santa Fe Railroad, and a former sewage treatment plant and transfer facility; and to the north by the San Joaquin River. The easternmost unit, the 14-acre Sardis Unit, is bordered to the west and east by PG&E property; to the north by the San Joaquin River; and to the south by Wilbur Avenue. The Georgia- Pacific gypsum plant and the Kemwater North American Company (Kemwater) are adjacent to the PG&E parcels to the west and east, respectively. Land Ownership The approved refuge boundary encompasses 67 acres, 55 of which are owned by the Service. The other 12 acres, owned by PG&E, are part of the same remnant dune ecosystem and include dune and riparian cover types. In the past (1985 to 1995), through a cooperative agreement with PG&E, the Service has conducted some management activities on PG&E land. The Service and PG&E are currently in the process of renegotiating the cooperative agreement. In the interim, PG&E has continued to allow biological surveys to be conducted on their lands. The approved refuge boundary identifies important and sensitive resource areas that the Service is looking to protect for a long period of time. Landowners within a refuge boundary retain all the rights, privileges, and responsibilities of private land ownership. After the Service Director approves a refuge boundary, the Service can make offers to purchase land, or enter into management agreements with willing landowners within the approved boundary. Lands do not become part of the Refuge System unless they are purchased or are placed under a management agreement with the individual landowner. The goals, objectives, and strategies outlined in this CCP address management of the 55 acres of Service-owned lands and do not pertain to private lands. Partnerships In addition to the PG&E partnership, described above, the Refuge has benefitted from the work of many scientists who have conducted research at the dunes. Refuge partners include the California Department of Fish and Game, Solano and Napa County Mosquito Abatement Districts, Mills College, University of California (UC) Berkeley, UC Santa Cruz, UC Davis, the California Department of Transportation (Caltrans), Center for Natural Lands Management, and many dedicated volunteers and individuals. Refuge Setting The Antioch Dunes were once a large, ancient, aeolian (wind blown) dune system extending along the southern bank of the San Joaquin River just east of the town of Antioch (Powell 1983). According to a 1908 U.S. Geological Survey topographic map the bulk of the dunes were along a two-mile stretch of the river, averaged approximately one-sixth of a mile wide and totaled roughly 190 acres (Howard and Arnold 1980). Sardis Unit USFWS Photo Antioch Dunes National Wildlife Refuge Antioch San Francisco Redwood City Sacramento Santa Rosa San Rafael Santa Cruz Fairfield Hollister Woodland Martinez Stockton San Jose Oakland Salinas Napa \|ÿ4 tu101 tu50 §¨¦505 §¨¦580 §¨¦80 §¨¦680 §¨¦5 \|ÿ1 \|ÿ29 \|ÿ160 \|ÿ1 tu101 Figure 1. Location Map CA/NV Refuge Planning Office - May 2003 I C A L IF O R N IA Are a En l a rg e d 10 5 0 10 20 Miles 5 Contra Costa Co. Sacramento Co. Lake Alhambra Sa n Jo aqu in Ri v er Wilbur Ave. Burlington Northern/Santa Fe R.R. West 18th East 18th Cavallo Dr. Fulton Shipyard Rd. Figure 2. Antioch Dunes National Wildlife Refuge CA/NV Refuge Planning Office, May 2003 I Stamm Unit Sardis Unit Flow U.S. Fish and Wildlife Service Lands Pacific Gas and Electric Lands Approved Refuge Boundary City of Antioch Unincorporated Contra Costa County Comprehensive Conservation Plan 7 Introduction Isolation of this sand dune habitat resulted in the development of species and subspecies of plants and insects that are found nowhere else in the world. Around the early 1900s, this biological “island” began to experience a dramatic change. Human development and sand mining destroyed most of the dunes that historically reached heights of 120 feet. The easily-accessible sand was mined to make bricks. Large-scale sand mining and industrial development continued to fragment the sand dune habitat until only a small portion of the original ecosystem remained. A small portion of the dunes were protected from further development and mining when the Refuge was established in 1980. However, nonnative weeds encroached on the sand dunes crowding the few remaining endangered plants. When the Refuge was established, only a few acres of remnant dune habitat supported the last natural populations of primrose, wallflower, and Lange’s. The Refuge was open for public use until 1986 when it was closed to protect the endangered plants from trampling and wildfires. Refuge History 140,000 years ago Sand dunes are formed by winds blowing loose sand off the coastal strand habitat. 10,000 years ago Horses, bison, camels, mastodons, and ground sloths live in the area. Their bones are found in the dunes in 1940. 1772 The Fages expedition finds a Native American village at the dunes. The habitat is oak woodland. Deer, antelope, tule elk, and beaver abound in the area. 1776 The de Anza expedition travels through present-day Antioch and the dunes. 1836 The Los Meganos Land Grant is awarded to Jose Noreiga. 1849 Settlers are encouraged to take up residence on the land grant. Smith's landing, on land grant land, will later be called Antioch. 1852 A brick factory is built in town. 1853 A dairy, piggery, sheepfold, and a store are established in the dunes and a shipyard will be built there later. Wild oats (Avena barbata, A. fatua) and red-stemmed filaree (Erodium cicutarium) introduced from Europe are growing in the dunes. Cattle roam freely in the area including the dunes. 1860s A vineyard is planted in Antioch Dunes. 1869 The first known botanical visit to the dunes is conducted by Albert Kellog, a founder of the California Academy of Sciences. 1889 Two brickyards are established in the Antioch Dunes. 1896 Wallflower is described by E.L. Greene. 8 Antioch Dunes National Wildife Refuge Chapter 1 1900 Tracks for the Atchison, Topeka, and Santa Fe Railroad are laid along the southern margin of the dunes. Spur lines into the dunes facilitate removing sand and bricks. e l t s i h t n a i s s u R . e l a s r o f d e v o m e r g n i e b s i d o o w d r o c k a O( Salsola tragus) is found in the Antioch Dunes. 1903 Wilbur Avenue is built, providing road access to the dunes. 1906 The San Francisco Earthquake occurs; much of the city will be rebuilt with bricks made of sand from the Antioch Dunes. 1909 The Great Western Power Company builds a transmission line across the dunes. This company will be acquired by PG&E. 1915 Three brick-making companies now operate in the dunes. 1930s The Stamm family acquires the western portion of the sand dunes, including the vineyard. The Stamms will mine sand from the property for almost half a century. The dunes are discovered by entomologists from the University of California and California Academy of Sciences. Ultimately, 29 new taxa will be discovered in the dunes. 1933 Various beaches, dance pavilions, wharfs, and recreational cottages attract visitors to the shore of the San Joaquin River. Antioch Beach is very popular. Lange's are discovered. They will be described by John Adams Comstock in 1938. 1936 John Thomas Howell and Alice Eastwood collect the first specimens of Antioch Dunes evening primrose which will be described by P.A. Munz in 1949. 1940 Jack Little buys an eastern parcel of the dunes from the owners of a brickyard. He builds the Little Corral Bar from the company's mess hall. Little will mine sand in the dunes for 33 years. Insect collectors from all over the west continue investigating the unique insect fauna found in the dunes. 1947 The Fibreboard Company purchases a parcel in the Antioch Dunes, clears the oaks, levels the sand, and builds a paper mill. Early 1950s Crown-Zellerbach builds another mill in the dunes. The City of Antioch buys land from the Stamms and builds a sewage treatment plant in the dunes. 1955 Life Magazine features the flora and fauna of the Antioch Dunes. 1976 Lange's is placed on the Federal Endangered Species List. Comprehensive Conservation Plan 9 Introduction 1977 Mildred Mathias andLincoln Constance describe a state listed rare plant, Mason's lilaeopsis ( Lilaeopsis masonii) collected from the dunes. Richard Arnold starts a capture and release population study to estimate the number of Lange's on the Antioch Dunes. 1978 The wallflower and the primrose are listed as endangered species. The dunes are designated "critical habitat." 1979 The wallflower and primrose appear on U.S. postage stamps. Congressman George Miller begins receiving mail from plant and butterfly fanciers from all over the country. The Service conducts negotiations with the property owners to establish a purchase price. The owners are prepared to sell the property to a developer for the construction of a marina and condominium complex. 1980 The Refuge is established, the first acquisition ever by the Service specifically for the protection of plants and insects. Cost of the 55 acres is $2,135,000. PG&E plants 445 seedlings of the buckwheat to protect the few remaining Lange's on its property. 1983 Most of the vineyard planted in the 1860s is restored to natural habitat. Arnold (1983a) concludes a capture and release population study of Lange's started in 1977. 1986 Service personnel and volunteers count 186 Lange's during the population peak count for that year. The Refuge is officially closed to all public use because endangered species are being trampled and illegal campfires are causing wildfires. 1991 3,000 cubic yards of riverine sand donated by PG&E are trucked into the Refuge to re-create habitat for the endangered species. 1992 PG&E donates an additional 4,000 cubic yards of sand to create new dunes. 1992-1995 Plants of many species native to the area, including the primrose, wallflower, and buckwheat, are planted on the new dunes. 1997 Prescribed burning is initiated to combat nonnative weeds. 10 Antioch Dunes National Wildife Refuge Chapter 1 (Arnold et al. 1983, Arnold pers. com. 1999; Howard and Arnold 1980; Loredo pers. com. 2000) Refuge Purpose The Refuge was established under the authority of the Federal Endangered Species Act of 1973 which provides for the protection of endangered and threatened species of fish, wildlife, and plants. In addition to providing a basis for making compatibility determinations, a refuge’s purpose also serves as a guide for refuge management and public use. The Refuge purpose is: “. . . to conserve fish, wildlife, and plants, including those which are listed as endangered species or threatened species . . . ” 16 USC § 1534 (Endangered Species Act of 1973). The Refuge was established in 1980 to protect a unique riverine dune ecosystem, including designated “critical habitat” and three endangered species. The 67 acres within the approved Refuge boundary, along with some lands on the Georgia-Pacific gypsum plant and Kemwater properties, support the last known natural populations of the endangered primrose, wallflower, and Lange’s. Land and Water Conservation Fund money was used to acquire lands. The acquisition was in accordance with the recovery plan for the three species (Service 1984). Related Projects and Studies in the Area U.S. Fish and Wildlife Service The Recovery Plan for the Primrose, Wallflower, and Lange’s In 1984, the Service prepared a Recovery Plan for Three Endangered Species Endemic to Antioch Dunes, California. The recovery plan describes the species and sets forth recommendations for managing the primrose, wallflower, and Lange’s. The plan identified fuelbreak maintenance (a barrier of cleared land intended to stop the spread of fire), public recreation, and nonnative weeds as the greatest threats to the endangered species. Recommendations included: � Acquiring the Stamm and Sardis properties; � Developing cooperative agreements for habitat management with landowners adjacent to these parcels; � Conducting additional research on the three endangered species to determine habitat requirements; � Monitoring the three endangered species to determine their population sizes; � Possible captive breeding of the Lange’s; � Propagating and planting buckwheat, primrose, and wallflower; � Rebuilding natural dune substrate and topography by adding sand; � Removing nonnative weeds, including the vineyard; � Restricting public access to both the Stamm and Sardis Units; and � Developing interpretive and environmental education programs. 1999 Service personnel and volunteers count 2,342 Lange's during the population peak count for that year. This is the highest count on record. Comprehensive Conservation Plan 11 Introduction Most of these recommendations were implemented or are in progress. The only recommendation not fully implemented was developing an interpretive and environmental education program. Although the Refuge has developed some interpretive and environmental education partnerships and programs, funding and staff to fully accomplish this recommendation have not been available. Other Agencies Brannan Island State Recreation Area Brannan Island State Recreation Area (SRA) was established in 1962 by the California Department of Parks and Recreation (DPR) and supports a self-sustaining population of primrose (Riblet pers. com. 2000). The Recreation Area is about 16 miles north of the Refuge, along the Sacramento River, Jackson Slough, and Three Mile Slough. The southern portion of Brannan Island consists of a dredge spoil area. Sands washed down the Sacramento River (probably from historic hydraulic mining activities in the Sierra Nevada Mountains) were dredged to deepen the Sacramento River Deep Water Ship Channel and deposited on the southern portion of Brannan Island. The dredged sand on the island is very fine and has been used to manufacture glass. Walter Knight, a former staff member of the Regional Parks Botanic Garden, planted primrose on “low dunes” of Brannan Island in 1969, as a possible solution to the “grave threat sand mining posed” to populations at Antioch Dunes. James Roof, director emeritus of the botanic garden, was the inspiration behind Knight’s action to initiate dispersal to remote dune areas suitable for primrose (Service 1984). Since then, there have been no management actions to enhance the primrose population. Although an area surrounding the planted primrose has been fenced, the primrose that has spread into other areas in the SRA have received no special protection. The new locations are not aligned with the existing population and prevailing winds on the island. Therefore, the seeds were probably not wind-dispersed. DPR believes that rabbits have spread primrose seeds on the island through their digestive tract (Riblet pers. com. 2000). The original planting location is in a protected area, along with several elderberry (Sambucus mexicana), host plant for the federally endangered valley elderberry longhorn beetle (Desmocerus californicus dimorphus). Other primrose growing outside the fenced area have been seen at the edges of pathways and along the beach. Park personnel have noted that the primrose seem to do better in these areas of disturbance. The Regional Parks Botanic Garden at Tilden Regional Park The East Bay Regional Park District owns and operates the Regional Parks Botanic Garden in Berkeley. The garden grows both the primrose and wallflower in small plots of no more than 200 square feet each. The primrose and wallflower have required diligent maintenance, including weeding and outplanting, to maintain their numbers. Montezuma Wetlands Montezuma Wetlands, near Collinsville, across the river from the Refuge, is a wetland restoration project demonstrating the beneficial reuse of dredge material. The project, which is being undertaken by private entities, will use dredge disposal material from the Federal channels of the Oakland Harbor and the berths that are maintained by 12 Antioch Dunes National Wildife Refuge Chapter 1 the Port of Oakland. About 1,800 acres of the site will be restored as wetland. An additional 50 acres will be used to dewater and desalinate dredge material for sale to other entities. Dredge material that is resold will be processed at a facility where the materials will be washed and cleaned prior to sale and placement. Montezuma Wetlands offers a potential source for clean sand (to restore dunes) close to the Refuge. CALFED CALFED, a consortium of stakeholders and Federal and State agencies, is developing a plan to address the agricultural, municipal and wildlife demands on the water supply of the Sacramento/San Joaquin River Delta (Delta). The Refuge is in the study area for the CALFED plan and has been specifically identified as a potential area for habitat restoration under the Ecological Restoration Program of CALFED. The CALFED Ecological Restoration Program Plan’s (1999) goals include protecting and enhancing the Refuge and surrounding dunes, the recovery of state listed rare species including, Mason’s lilaeopsis (Lilaeopsis masonii), Suisun marsh aster (Aster lentus), delta tule pea (Lathyrus jepsonii var. jepsonii), and Federally endangered species including Lange’s, primrose, and wallflower, all of which can be found on the Refuge. Comprehensive Conservation Plan 13 Chapter 2 - The Planning Process The Planning Process The process followed for developing this CCP was guided by the Refuge Planning Chapter of the Fish and Wildlife Service Manual (Part 602 FW 2.1, November 1996) and evolving policy related to the Refuge System Improvement Act of 1997. Key steps include: � Preplanning; � Identifying issues and developing vision; � Gathering information; � Analyzing resource relationships; � Developing alternatives and assessing environmental effects; � Identifying a preferred alternative; � Publishing the draft plan; � Documenting public comments on the draft plan; � Preparing the final plan; � Securing approval of the California/Nevada Operations Office; and finally, � Implementing the plan. The CCP may be amended as necessary at any time under an adaptive management strategy. If major revisions are needed, public involvement and NEPA review would be required. In a Federal Register Notice, dated December 30, 1998, the Service announced that it was preparing a plan for the Refuge. The first Refuge planning update, December 1998, informed the public about the Refuge and the planning process. When the update was written, Refuge and planning staff did not anticipate much general interest in, or controversy over, Refuge management and decided not to schedule a public scoping meeting, unless requested by the public. Instead, the planning update encouraged the public to provide comments and concerns about Refuge management via e-mail, phone, or mail, with the understanding that the Service would hold a meeting if public interest in, or controversy over, Refuge management was high. No meeting was held because the planning update generated no requests for a meeting and little controversy. A technical panel was convened in February of 1999 to assemble nearly 20 scientists who have conducted research at the Refuge and other experts. The panel spent a day discussing the implications of their research on Refuge management. The panel included university faculty and staff, consultants, graduate students, other agency personnel, and Service personnel (Appendix B). 14 Antioch Dunes National Wildife Refuges Chapter 2 The second planning update, May 1999, described the issues, concerns, and opportunities identified at the technical panel. A second technical panel was convened in November 1999 to solicit comments and provide answers to questions on the draft documents. The third planning update, July 2000, discussed the goals and objectives. The fourth planning update, July 2001, announced the upcoming draft CCP and informed the public about how to comment on the draft CCP. The fifth planning update, March 2002, announced the upcoming final CCP and gave the public the choice of receiving either the complete document or a summary. The draft CCP and Environmental Assessment (EA) (Appendix C), were distributed to Refuge partners, adjacent landowners, government agencies, local jurisdictions, community groups, and private citizens in August 2001. The public had 30 days from its release to provide comments. The response to these comments is Appendix D. Implementation of the CCP began after the finding of no significant impact was signed. The EA is available on file at the Refuge and with the California/Nevada Refuge Planning Office in Sacramento, California. The CCP will be reviewed by Refuge staff while preparing annual work plans and updating the Refuge Operational Needs System database. This database describes the unfunded budget needs for each refuge and is the basis upon which the Refuge receives funding increases for operational needs. The plan may also be reviewed during routine inspections or programmatic evaluations. Results of the reviews may indicate a need to modify the plan. Periodic review of the objectives and strategies is an integral part of the plan and management activities may be modified if the desired results are not achieved. If minor changes are required, the level of public involvement and NEPA documentation will be determined by the refuge manager. The CCP will be formally revised about every 15 years. Issues Issues, concerns, and opportunities were identified through discussions with planning team members, members of the technical panel, other key contacts, and through the public scoping process. Comments were received in writing, via e-mail and regular mail. The following issues, concerns, and opportunities are a compilation of information developed by the Service throughout the planning process. The most significant issues identified are nonnative weeds, public use, trespassing, and wildfires caused by illegal campers. Issues Identified by the Public � Open the Refuge to the public for fishing and swimming. � Provide guided tours of the Refuge. � Provide opportunities for volunteers. � Maintain the Refuge as a sanctuary. � Extensive nonnative weeds should be controlled by burning (where appropriate), herbicide application, and mechanical removal methods. � Restrict native plantings until nonnative weeds are under control. � Provide a part-time caretaker to repair fences and practice nonnative weed control. An off duty fireman could possibly oversee the refuge and provide a presence on the Refuge. Comprehensive Conservation Plan 15 The Planning Process Issues Identified by Refuge Staff, Panel of Experts, and Other Agencies � Develop and complete an agreement with PG&E for long-term management of the 12 acres they own within the approved Refuge boundary. � Control nonnative weeds. � Identify and develop techniques for successful restoration. � Consult with experts in dune ecology, restoration, and nonnative weeds. � Explore methods of creating sand disturbances in the dunes. � Investigate effects of prescribed burning on air quality. � Address lack of adequate funding and staff. � Determine scope and compatibility of public use. � Increase efforts to stop trespassing and vandalism. � Conduct more research on the effect of fire on native insects. � Explore public use - most are not compatible. � Explore possible land acquisition, by fee title or easement. � Investigate effects of wildfires. Resource issues and opportunities were also identified during the scoping process. The results of this effort are described in Chapter 4, Problems and Opportunities. Contra Costa Wallflower on sloping terrain USFWS Photo 16 Antioch Dunes National Wildife Refuges Chapter 2 Comprehensive Conservation Plan 17 Chapter 3 - Refuge and Resource Description The Refuge is in the Delta which sits in the San Francisco Bay-Delta Watershed, a 61,000 square mile area of California (CALFED 2001). The Delta is 750,000 acres of tidal marshland, shallow backwater swamps, farmland, and municipalities (California Department of Fish and Game and the Service 1980). The Refuge occupies a unique place within the ecoregion in that inland dunes are limited within the Delta, found only in the Refuge area (CALFED 1999). The Refuge is near the southwestern boundary of the Delta, about five miles upstream of the confluence of the Sacramento and San Joaquin Rivers. The Delta contains hundreds of miles of interlaced waterways and is the major collection point for water that serves two-thirds of California’s population (California Department of Water Resources 1995). Before flows were regulated and the rivers channelized, the Delta was characterized by sluggish river channels, oxbow and floodplain lakes, swamps, and sloughs. Native fish thrived in weedy backwaters and large stretches of open water. The region’s dense tules, willows, and cottonwoods supported more than 250 species of birds and mammals. The 55-acre Refuge, along with the 12 adjacent acres owned by PG&E and a few adjacent acres of land, is all that remains of a unique system of riverside sand dunes that once reached heights of 120 feet and stretched along two miles of the southern bank of the San Joaquin River east of Antioch (Roof 1969). Beginning in the 1880s, Antioch Dunes’ pure sand was systematically mined for use in brick making and construction. Today, the last remnants of the dunes are surrounded by a shipyard, a gypsum plant, and a former sewage treatment plant and vary from zero to 50 feet high. The Refuge currently exists as an isolated habitat surrounded by industrial development (Service 1997b). The existing habitat has been highly altered by sand mining and agriculture, which is reflected in extensive weediness and the inability to support healthy populations of native species. 18 Antioch Dunes National Wildife Refuge Chapter 3 As required by Service planning policy, a wilderness review (Appendix E) was conducted for the Refuge. None of the Refuge lands were eligible for wilderness designation. In an effort to divide the Refuge into areas with similar topographic features and/or species abundance, the Stamm and Sardis Units have been divided into different management areas (MA) (Figures 3 and 4). The Stamm Unit terrain is characterized by rolling dunes ranging from zero to 50 feet high, as measured from the river water surface elevation. The Sardis Unit, which ranges from 1 to 50 feet high is between two higher parcels owned by PG&E. The PG&E parcels are about 80 feet above the water surface elevation. It is likely that the PG&E parcels more closely resemble the native topography than the Refuge units because the PG&E parcels were never mined for sand (Loredo pers. com. 1999). In 1927, the northern portion of the eastern PG&E parcel was leveled to construct a tower. The central and southern portions of this parcel, two or three acres, were never developed and are the only sections in the Refuge area that retain original height and contours (Arnold et al 1983). It is presumed that the western PG&E parcel is naturally fairly level. The aeolian sand at the Refuge is contiguous with the sheer aeolian sand underlying much of the flat lands between the Mount Diablo foothills and the western margin of the Delta. Most of the exposed aeolian sand near Antioch accumulated between 10,000 and 40,000 years ago, during the late Pleistocene period. Atwater (1982) theorized that most of the exposed sand at the Refuge accumulated during the most recent major glaciation of the Sierra Nevada. The retreating glaciers deposited glacially eroded sand and silt onto the floodplains of the Central Valley’s rivers and drainages. Summer winds sweeping the floodplains would have picked up the sand and deposited it as dunes, generating the dune field of eastern Contra Costa County. Evidence of at least two discrete episodes of aeolian deposits is exposed in a river bluff adjacent to the Refuge. About 50 feet of young sand dunes, from the last glaciation, overlies 5 to 6.5 feet of older sand dune. Though dunes could have formed near Antioch at least five times during the last 500,000 years, the penultimate deposits probably occurred 140,000 years ago (Atwater 1982). Thus a hiatus of 100,000 years may separate the last two episodes of sand dune formation at Antioch (Atwater 1982). The dunes were formed by ancient deposits of glacial sands carried downriver from the Sierra Nevada, left isolated along the river after the Mojave Desert receded in prehistoric times. Over thousands of years, ocean winds and bay tides slowly shaped these sands into high dunes. Isolation of this sand dune habitat resulted in the development of species and subspecies of plants and insects that are found nowhere else in the world. HARDPAN #2 SCARIFIED TRIANGLE HARDPAN #1 NORTH EAST HARDPAN #3 SOUTH OF PATH EAST PLATEAU RESTORED VINEYARD HARDPAN #4 PLATEAU 1995 DUNES ACCESS ROAD ENTRY CAR BODY HARDPAN SLOPE RIVER SLOPE TRIANGLE SECTION TO OAK BLOWOUT VINEYARD PLATEAU RIVER 2.63 4.14 1.18 2.65 3.58 2.33 2.50 1.56 5.89 2.88 2.80 0.20 2.19 3.43 1.19 1.36 1.18 S a n J o a q u i n R i v e r Georgia- Pacific Gypsum Plant Ful ton Ship yar d Ro ad Fulton Shipyard Wilbur Avenue Burlington Northern / Santa Fe R.R. Minaker Drive Figure 3. Management Areas with Acreages - Stamm Unit - Antioch Dunes National Wildlife Refuge 100 0 100 200 300 400 500 I Feet CA/NV Refuge Planning Office - May 2002 Note: All units are in acres. Approved Refuge Boundary Management Areas PIT FLOOR WEST SOUTH OF CABLES SOUTH PLATEAU 1995 1992 DUNES EAST OF CORRIDOR PLATEAU 1995 DUNES 1993 DUNES RIVER FLAT WEST OF CORRIDOR PLATEAU SOUTH SLOPE WEST SLOPE EUCALYPTUS HILL CORRIDOR NORTH OF TOWER ACCESS ROAD SLOPE 1992/1993 NEW DUNES RIVER CREST TOWER NORTHWEST SLOPE SOUTHWEST CORNER SLOPE SMALL INNER HILL NORTH AND EAST OF TOWER RIVER CREST TRIANGLE NORTH SLOPE EAST SLOPE NORTH SLOPE (PG&E) S a n J o a q u i n R i v e r Georgia- Pacific Gypsum Plant Wilbur Avenue Kemwater Domtar 0.02 0.04 0.08 0.28 0.37 0.08 0.13 0.1 0.19 0.2 0.32 0.37 0.38 0.48 0.49 0.51 0.93 0.89 0.95 1.22 1.88 2.04 2.46 3.18 2.9 5.67 Figure 4. Management Areas and Acreages - Sardis Unit - Antioch Dunes National Wildlife Refuge 100 0 100 200 300 400 Feet CA/NV Refuge Planning Office - May 2002 I Approved Refuge Boundary Survey Areas on PG&E Property Management Areas on USFWS Property Note: All units are in acres 20 Comprehensive Conservation Plan 21 Refuge and Resource Description Carpenter and Cosby (1939) mapped the Refuge area as Oakley Sands. Soil types at the Refuge have been classified as ranging from sand to sandy-loam; pH averages 6.4 (range 5.6 to 7.0). The Service hired a contractor to collect and analyze soil samples from several sites at the Refuge. The soils report (Jones and Stokes 2000) indicated that the Refuge lacks a true soils association. The native soils have been severely mined, from a height of about 120 feet to a current height at about 10 to 50 feet. The Antioch area has a modified Mediterranean climate with hot dry summers and moist, mild winters. Rainfall averages 12.5 inches annually, falling mainly from November through April. Typically, the months of May through September are dry. The average annual temperature is 61.8°F with an average annual maximum temperature of 74°F. Average high temperatures in the area range from above 90°F in July, August, and September to the mid-50s°F in December and January. The hottest recorded temperature is 114°F, and the lowest recorded temperature is 14°F. Summer winds blow from the river from the west or northwest at an average of 10 to 20 mph. Because the area is exposed to winds both from the west and east, and the terrain provides little protection from the wind, the Antioch area has good air flow. Average wind speeds in the Antioch area are relatively high and calm conditions are infrequent. The air quality near Antioch is generally good. However, there are point sources of air pollution near the Refuge that potentially affect air quality on the Refuge. The Sardis Unit is adjacent to and generally downwind of the Georgia-Pacific gypsum plant which emits gypsum dust that covers vegetation in surrounding areas. The Southern Company power plant, owned by PG&E until 1999, is about one mile from the eastern boundary of the Refuge. The Southern Company plant emits benzene (35 lbs/yr) and formaldehyde (1,700 lbs/yr) (BAAQMD 1999a). Air pollution generated by the Refuge is caused by temporary, short term disturbances, such as annual prescribed burning and earthmoving activities. There is currently limited public use allowed on the Refuge and there are minimal maintenance activities; on-site vehicular emissions are infrequent. The State Air Resources Board has statewide responsibility for air quality in the area, and the Bay Area Air Quality Management District (BAAQMD) has permitting authority for stationary air pollutant sources in the region. The BAAQMD regulates federally regulated air pollutants, particulate matter, organic compounds, nitrogen oxides, sulfur dioxide and oxides, carbon monoxide, hydrogen sulfide, ground level ozone, and acid deposition. Air quality in Contra Costa County is generally good. Because the air quality monitoring station closest to the Refuge (in Pittsburg, CA) has exceeded air pollution standards for ozone twice for the maximum one-hour emission and once for the maximum eight-hour emission, the county is a nonattainment area (BAAQMD 1999b). Contra Costa County contains a multitude of air pollutant sources. Controls placed on automobiles and stationary sources of air pollutants, such as factories 22 Antioch Dunes National Wildife Refuge Chapter 3 and refineries, as well as on nonpoint sources such as paints, solvents, and gas stations, have not resulted in all air quality standards being attained in the Bay Area. Inventories of these sources have been prepared by the BAAQMD (BAAQMD 1999a and 1999b). Mobile sources, including automobiles, busses, and trucks contribute about 50 percent of the air pollutants and air toxins (Richardson pers. com. 2001) except for sulfur dioxide, which is primarily generated by petroleum refining and power plants (deBecker pers. com. 2001). The Antioch area contains a large portion of the industrial sources of pollutants within Contra Costa County, and is downwind of both the greater Bay Area and the Diablo Valley. As a result, ozone levels exceed both the Federal and State standards. Carbon monoxide, sulfur dioxide, nitrogen dioxide, lead, and hydrogen sulfide levels are within the Federal and State standards. There is concern that gypsum dust from the adjacent gypsum plant may affect plant health, particularly that of the endangered species, by affecting soil chemistry and/or photosynthesis (gypsum is a common fertilizer and soil additive). Many plants on the PG&E parcels and Sardis Unit are covered with a fine layer of gypsum. The gypsum suspended in the air is also a health concern for Refuge staff and visitors. The Service’s Denver Engineering Division contracted for a contaminants survey of the Refuge in 1999 with Clark and Witham. Phase I of the survey included site reconnaissance, reviewing historical use of the site, and reviewing records and reports of environmental incidents at or near the Refuge. Phase II included the collection and analysis of soil and ground water samples from the Refuge. Past land uses had indicated that the survey should pay special attention to potential creosote, pesticides, and asbestos contamination. The survey found that no environmental incidents involving the release of chemicals to the soil or ground water are recorded to have occurred on the Refuge nor on the properties owned by Fulton Shipyard, Georgia- Pacific, the railroad, or the former sewage treatment plant. Soluble metals and other contaminants are recorded as present in the soil and ground water at the Kemwater plant. Pesticides, creosote, and asbestos testing of soil samples gave results below detection limits set by the analytical laboratories, except for a soil sample from the Sardis Unit which indicated the presence of chlordane. The chlordane encountered on the Sardis Unit, based on past land use and the half life of this chemical, is most likely a remnant of past agricultural land use. Chlordane was applied directly to soil or foliage to control a variety of insect pests on corn, citrus, deciduous fruits and nuts; for home, garden, and ornamentals; lawns, turf, ditch banks, and roadsides. Groundwater samples for pesticide and creosote were below the detection limits set by analytical laboratories. Chrysotile, however, was found at about 20 feet below the surface at Hardpan 1 and 2 MAs (Stamm Unit, Figure 3). Chrysotile is a natural asbestos found throughout California. It is common to find chrysotile in soil and groundwater in the San Francisco Bay Area, and given the depth and location of the chrysotile, the chrysotile observed in the groundwater at these two sites appears to be natural. Although the survey found no contaminant issues that currently affect the Refuge, the report Comprehensive Conservation Plan 23 Refuge and Resource Description recommends that further contaminants monitoring should concentrate on ground water monitoring along the eastern boundary of the Sardis Unit (adjacent to the Kemwater Plant) and along the southern boundary of the Stamm Unit (adjacent to the former sewage treatment plant). The San Joaquin River forms the northern boundary of the Refuge. The Refuge’s tidally influenced river frontage is about two-thirds of a mile long. The riparian corridor generally, is less than 10 feet wide due to the tall and steep embankments along the river’s edge. Like most of the Refuge, the riparian corridor has been altered and contains nonnative weeds. The San Joaquin River adjacent to the Refuge is affected by the saline conditions of the ocean and, together with the rest of the Delta outflows, flows at around 32,000 cubic feet per second in winter (California Department of Water Resources 1995). Tides in the area cause water level fluctuations from about 3 feet above sea level at high tide to about 2.2 feet below sea level at low tide during a typical tidal cycle. The groundwater beneath the Refuge is predominately influenced by the level of the San Joaquin River. As the ocean tides raise and lower the surface elevation of the river, the groundwater level fluctuates in response. Groundwater level at Hardpan 1 MA is approximately 15 feet below the surface, 27 feet at the Restored Vineyard MA, and 17 feet at the Car Body MA on the Stamm Unit (Clark and Witham 1999). Refuge management requires very little water. No water is currently being used for irrigation. Water, used for fire suppression, is supplied from a hydrant by the southern boundary of the Stamm Unit. The Refuge is in the Contra Costa Water District. Historic accounts of the Refuge indicate that oak woodland was the primary vegetative community at the Antioch Dunes. The presence of oak woodland suggests that there was a stabilized substrate, however, it is also known that native flora, such as wallflower, primrose, butterweed (Senecio sp.), and California matchweed (Gutierrezia californica) would have required dynamic substrate as well. It is possible that slumping caused by weather, gravity, falling trees, wind erosion, and natural plant senescence would have provided occasional open areas of sand that would have been colonized by the sand-loving primrose. It is not known what role, historically, fire played in the Antioch Dunes ecosystem. Three main habitat types are found within the 67 acre approved Refuge boundary (Figure 5): littoral (owned by State Lands Commission), riparian, and unique stands at Antioch Dunes (Sawyer and Keeler-Wolf 1995). The littoral zone, along the Littoral zone where Mason’s lilaeopsis is found. USFWS Photo S a n J o a q u i n R i v e r S h i p y a r d R d . F u l t o n Burlington Northern / Santa Fe R.R. Wilbur Ave. Minaker Dr. 100 0 100 200 300 Meters CA/NV Refuge Planning Office - May 2002 I Figure 5. Three main habitat types at Antioch Dunes National Wildlife Refuge. Approved Refuge Boundary PG&E Property Riparian Antioch Dunes Unique Stands (Sawyer, Keeler-Wolf 1995) Littoral Zone Comprehensive Conservation Plan 25 Refuge and Resource Description river’s high and low watermarks, contains a state listed rare plant, Mason’s lilaeopsis as well as other rare species including Suisun marsh aster (Aster lentus), Delta mudwort (Limosella subulata), and Delta tule pea (Lathyrus jepsonii var. jepsonii). Other littoral zone species include cattail (Typha angustifolia), tufted hairgrass (Deschampsia cespitosa), alkali marsh butterweed (Senecio hydrophilus), and low club rush (Scirpus cernuus). The riparian area is characterized by native species such as coast live oak (Quercus agrifolia), narrow-leaved willow (Salix exigua), arroyo willow (Salix lasiolepis), toyon (Heteromeles arbutifolia), and elderberry (Sambucus mexicana). A steep embankment at the river’s edge provides a narrow space for riparian vegetation. The riparian corridor has been altered and contains nonnative weeds such as oleander and pampas grass. Irregularly shaped pieces of broken concrete slabs have been placed on the river bank at the west end of the Stamm Unit, perhaps serving as revetment. The “unique stands at Antioch Dunes” (a separate cover type) as described by Sawyer and Keeler-Wolf (1995) consist of scattered forbs and grasses which form a ground canopy and uplands consisting of stabilized or partially stabilized dunes. In addition to the primrose, wallflower, and buckwheat, other common native plants in the dunes include elegant clarkia (Clarkia unguiculata), California poppy (Eschscholzia calfornica), California croton (Croton californicus), Grindelia (Grindelia sp.), deerweed (Lotus scoparius), telegraph weed (Heterotheca grandiflora), California matchweed (Gutierrezia californica), and silver bush lupine (Lupinus albifrons). These native plants, which composed these “unique stands,” still exist on the Refuge, mostly in areas that have had the least amount of sand mining or human degradation or in areas that have been intensively managed. The unmined fringe areas along the river in the Stamm and Sardis Units have concentrations of native species (Service 1997b). The highest proportion of native species on the Refuge, including the primrose, wallflower, buckwheat, croton, deerweed, and many others (Appendix F) have traditionally been found on the open dune area of the Blowout MA (Stamm Unit, Figure 3). The Blowout MA most represents the historical ecology of the original riverine dunes including the original topography, sandy nutrient-poor soils, and wind currents. The native plants in this MA also seem to be shorter and less robust than in other areas, indicative of plants in this ecological region. The viability of native plants on the Refuge is one of the Refuge’s primary concerns. Once a diverse habitat for many types of insects and wildlife, the dunes now support thriving nonnative weed populations that do not support the same invertebrate diversity (see invertebrates section). Before the Refuge was established, the areas with the highest concentration of nonnative weeds were disced (turning large discs through the soil using heavy equipment) annually (Powell 1983). This area included the unmined southern portion of the Sardis Unit, along with its mined-out pit. Some of these areas have been colonized almost entirely by nonnative weeds. As a result, the Refuge no longer uses discing as a weed control measure. Nonnative weeds dominate some areas of the Refuge. Primarily of concern are ripgut brome (Bromus diandrus), yellow starthistle (Centaurea solstitialis), vetch (Vicia spp.), and Russian thistle (Salsola tragus). 26 Antioch Dunes National Wildife Refuge Chapter 3 The Refuge provides important habitat for many types of wildlife, including mammals, reptiles, and resident and migratory birds. Historical accounts indicate that mink (Mustela vison), desert cottontail rabbit (Sylvilagus auduboni), beaver (Castor canadensis), muskrat (Ondatra zibethica), opossum (Didelphis marsupialis), weasel (Mustela frenata), and skunk (Spilogale gracilis) were found at the Refuge. Recent observations of mammals have been limited. Gopher (Thomomys bottae), gray fox (Urocyon cinereoargenteus), Beechy ground squirrel (Spermophilus beecheyi), coyote (Canis latrans), blacktail jack rabbit (Sylvilagus bachmani), muskrat, raccoon (Procyon lotor), Townsend’s mole (Scapanus townsendi), weasel, and red fox (Vulpes fulva) are mammals recently seen at the Refuge. Gopher mounds and rabbit droppings abound. Fox and squirrel burrows and dens are also commonly observed. Beaver have also been seen along the river’s edge. In 1977, Papenfuss, then a graduate student at UC Berkeley, completed an inventory of Refuge reptiles, including the California legless lizard (Anniella nigra), side-blotched lizard (Uta stansburiana), coast horned lizard (Phrynosoma coronatum), San Joaquin whipsnake (Masticophis flagellum ruddocki), glossy snake (Arizona elegans), western whiptail lizard (Cnemidophorus tigris), and the fence lizard (Sceloporus occidentalis). In 1982, Papenfuss followed up this inventory with an effort to trap herpetofauna on the Refuge and identify which species were still present. Only two species of reptiles were found at that time, side-blotched lizards and fence lizards. Since then, few reptiles have been reported or collected on the Refuge. No amphibians were found, however, historical collections for the Refuge include the western toad. Two California legless lizard sightings occurred in 2000. Fence lizards, gopher snake (Pituophis melanoleucus), and racers (Coluber constrictor) have been seen on the Refuge recently (Loredo pers. com. 2000b). Numerous bird species have been observed on the Refuge, including migratory and resident birds. Appendix G lists birds found at the Refuge. Gadwalls (Anas strepera) and mallards (A. platryhynchos) have also been observed nesting on the Refuge (Buffa pers. com. 2001). ! The Service’s Sacramento/San Joaquin Estuary Fishery Resource Office has monitored fish populations in the San Joaquin River from a beach seining station on the Refuge monthly since 1979. Listed species caught offshore of the Refuge include winter-run chinook salmon (Oncorhynchus tshawytscha) (federally and state listed endangered), delta smelt (Hypomesus transpacificus) (federally and state listed threatened), steelhead trout (O. mykiss) (federally threatened), and Sacramento splittail (Pogonichthys macrolepidotus) (federally threatened). The complete list of fish species found at the Refuge sampling station is included as Appendix H. " # $ Antioch Dunes has been known as an entomological hotspot since the 1930s when entomologists began collecting specimens in what is now the Sardis Unit. The area attracted attention for its large and colorful Comprehensive Conservation Plan 27 Refuge and Resource Description species with desert affinities. In the 1930s, many species of wasps and flies, particularly the giant flower-loving fly (Rhaphiomydas trochilus) were completely new to the region’s collectors. A total of 27 taxa were described from Antioch Dunes during this decade. Today we know that eight of these taxa are endemic to Antioch, four are now extinct, three are of uncertain status, and the eighth is Lange’s, discussed in the Endangered Species section. J.A. Powell and associates conducted an insect survey at the Refuge from 1976 to 1982, following a seasonal visitation schedule similar to that of past collectors but with a higher frequency during late summer and fall, compiling 94 visits representing all months (Powell 1983). Because no complete historical list of insects for the Antioch area exists, Powell chose 14 families to form a basis of comparison with historical collections, based on their sand-dune affinity characteristics. Three eras of insect collections were examined in detail: 1933-39 (extensive sand-mining), 1948-54 (extensive industrial buildup), and 1976-84 (final sand-mining and extensive weediness). Powell found no significant difference between the diversity (number of species) recorded in the three selected eras. He noted, however, that collectors of early eras did not sample thoroughly; data indicate that in the 1930s workers overlooked small and nocturnal species, while those of the postwar era overlooked small species to a lesser degree and tended to ignore some families. Therefore, Powell suggests that decline in diversity is best documented by species disappearance. Only 69 percent of the 279 species recorded more than once in previous surveys were observed during Powell’s 1976-82 survey. Loss of insect species at the Refuge happened surprisingly early – 35 species have not been sighted since the 1930s – and showed no marked correlation with an exploitation event. The extinction rate was gradual until the period of his study, when it appeared the extinction rate rapidly increased. In January 1995, Wes Maffei of the Alameda County Mosquito Abatement District began investigations to assess the presence or absence, approximate abundance, and the distribution of special status insects at the Refuge (Maffei 1997). Though a total of 249 insect taxa were identified, only three special status taxa were found: the robber fly (Efferia antiochi), the scarab beetle (Polyphylla stellata), and Lange’s. Maffei found only 35 percent of species that Powell recorded in his 1976- 82 surveys in the major families that were investigated. In particular, Maffei found a decline in native bee species, the pollinators of most of the native plants. Powell believes the declines are the result of nonnative weeds and lack of soil disturbance (Powell pers. com. 1999). Maffei noted this as well; in the 1995 Dunes MA (Stamm Unit, Figure 3), an increasing loss of insect species occurred as the nonnative weed cover increased with each successive season, resulting in minimal sand movement (Maffei 1997, Maffei pers. com. 2000). According to Maffei’s study, a number of insects have colonized the Refuge since the industrial buildup and sand mining of the early 1950s. This would be expected of species that occupy weedy habitats, but even among the flies and wasps, several newcomers have been recorded. This is best documented in spider wasps (Family Pompilidae) where the diversity clearly increased from entomologist collections 30 years ago. Maffei’s insect list is included as Appendix I. 28 Antioch Dunes National Wildife Refuge Chapter 3 The three federally listed endangered species–wallflower, primrose, and Lange’s – are found within and near the approved Refuge boundary. The California Natural Diversity Database also lists twelve species that are Federal “species of concern” at the Refuge, which have no protection under the Endangered Species Act: the Antioch Dunes anthicid beetle (Anthicus antiochensis, last seen in 1953 and probably since extinct or extirpated from this location), San Joaquin dune beetle (Coelus gracilis, last seen in 1974 and probably since extinct), the Antioch cophuran robberfly (Cohpura hurdi, last seen in 1939), Antioch efferian robberfly (Efferia antiochi, last seen in 1959), yellow-banded adrenid bee (Perdita hirticeps luteocincta, last seen in 1936 and probably since extinct), Antioch adrenid bee (Perdita scituta antiochensis, last seen in 1977), Antioch mutilid wasp (Myrmosula pacifica, last seen in 1952), Antioch specid wasp (Philantus nasalis, last seen in 1959), Middlekauf ’s shieldback katydid (Idiostatus middlekaufi, last seen in 1965), the Suisun marsh aster, Mason’s lilaeopsis, and the delta tule pea. The California Natural Diversity Database also lists three State listed species that have been found within or near the approved Refuge boundary. These species include Mason’s lilaeopsis (rare), primrose (endangered), and the wallflower (endangered). Lange’s Metalmark Butterfly - Apodemia mormo langei Background The Lange’s was first discovered in 1933 and was described five years later. In June 1976, this local subspecies was one of the first eight insects to be listed as endangered under the Federal Endangered Species Act. Following the listing, the Lange’s remnant habitat was purchased by the Service and designated a Refuge (Powell and Parker 1993). Lange’s continue to inhabit the Refuge, with their populations concentrated in the 1992 and 1993 Dunes at the Sardis Unit, and the Blowout MA and 1995 Dunes at the Stamm Unit (Figures 3 and 4). The Refuge, in addition to the PG&E property and a portion of the Kemwater property provides about 70 acres of suitable habitat and constitutes the entire present range for the Lange’s. Lange’s, like most butterflies, has a close relationship with its larval food plant, the buckwheat, and produce one brood per season. Adults typically begin to emerge in late July or early August and can be observed until mid-September. Numbers typically peak two or three weeks following the earliest emergence of a butterfly from a pupal case. The peak in male emergence is generally earlier than that of females (Powell and Parker 1993). They live for approximately one week during which they feed, mate, and locate the host buckwheat on which to deposit the eggs. Lange’s Metalmark Butterfly R.A. Arnold Comprehensive Conservation Plan 29 Refuge and Resource Description Female Lange’s lay eggs throughout the adult flight period. The gray eggs are deposited, in clusters of two or four, on the stem axils of the lower half of the buckwheat, where the foliage is withered. The eggs remain attached and dormant until the rainy season, at which time new growth of buckwheat appears, the eggs hatch and the larvae crawl to the base of the plant where they overwinter and feed on new foliage (Arnold 1983b). The larvae are nocturnal feeders and feed on new plant growth through the winter and spring. Pupation occurs in midsummer in the litter at the base of the buckwheat (Service 1984). Powell found that adults of both sexes are perchers and are capable of long flights between perches (Service 1984). The majority of males move locally (less than 100 feet) while females may travel up to 1,300 feet. Both sexes prefer buckwheat flowers as perches and as a nectar source. Females tend to be more mobile, visiting a greater variety of secondary nectar sources and searching for egg-laying sites. Males, on the other hand, tend to perch and aggregate more than the females. The primary limiting factors for the Lange’s are availability of nectar sources for adults, adequate host plants for egg-laying, and sufficient food for larvae (Service 1984). The highest density of buckwheat on the Refuge can be found in open areas, where nonnative ripgut brome and yellow starthistle can be found. Invasion by nonnative weed is detrimental to the Lange’s because it reduces the amount of suitable buckwheat stands available for habitat. Modification of the microclimate at the base of the buckwheat plants, which is also affected by nonnative weed encroachment, also seems to reduce the viability of the larvae (Arnold and Powell 1983). Moreover, additional losses of buckwheat were caused by past discing for fuelbreaks and by wildfires. At the Sardis Unit in 1976, a wildfire consumed some of the Lange’s habitat, but the Lange’s has managed to regain its former numbers. In 1999 a wildfire in the Blowout MA of the Stamm Unit destroyed part of the best Lange’s habitat. The buckwheat quickly resprouted and Lange’s are beginning to move back into the area, presumably from adjacent management areas that were not affected by the wildfire. Population Size and Status Prior to 1985, population estimates for the Lange’s were obtained from mark and recapture methods used by R.A. Arnold (1983a). From 1977 to 1983, Arnold documented a decline from more than 2,000 individuals to fewer than 400 reproducing individuals (effective adult population number) (Arnold 1983a). Arnold concluded that the Lange’s population decline was linearly correlated with the loss and alteration of habitat. Also, a trend analysis suggested that if then current habitat conditions continued, the extinction of the Lange’s at the Sardis and Stamm Units, the PG&E parcels, the Georgia-Pacific gypsum plant, and Kemwater property, could have occurred within one to five years (Arnold 1983a). Then, in 1985, Arnold documented a Lange’s population increase at both the Sardis and Stamm Units, 1.6 times greater and 2.2 times greater, respectively, than in 1984. Since the population rebounded from its low in 1982, Arnold theorized that at least 400 is a viable, self-sustaining population size for the Lange’s (Second Technical Panel 1999). Arnold conducted a captive breeding program for the Lange’s in the early 1980s, following the low counts. The program was discontinued after one season because habitat improvement was considered a more effective means of increasing the Lange’s population (Arnold pers. com. 2001, Arnold 1985, Arnold 1981). 30 Antioch Dunes National Wildife Refuge Chapter 3 It should be noted that Arnold’s population count methodology is different from the Refuge staff ’s current low impact peak count methodology that began in 1986 (Figure 6). Arnold captured, counted, and marked the Lange’s daily. He could distinguish which Lange’s had been counted already and which had not. Population estimates were calculated using these counts. The Refuge’s current methodology counts Lange’s once a week during their flight period (August to September) and uses the highest count during those surveys as the year’s peak count, without distinguishing between individuals that have already been counted (Arnold pers. com. 2001). The peak count of the adult butterflies are used as an annual index of the relative size of the population. The highest peak count was in 1999 with more than 2,342 Lange’s counted. Arnold’s population count could be as much as five to ten times the Refuge’s weekly peak count. The different sampling methods cannot be directly compared (Parker pers. com. 2000). Table 1 provides a summary of general trends for the three endangered species. Antioch Dunes Evening Primrose, Oenothera deltoides spp. howellii Background The primrose is a member of the Onagraceae family, subgenus Anogra. In 1949, the primrose was recognized as a separate variety by Munz. In 1962, Klein distinguished it as a subspecies. The primrose was federally listed as endangered in 1978. The primrose is endemic to Antioch Dunes; its naturally occurring population is confined to the two disjunct units of the Refuge, the PG&E parcels, and a portion of the Kemwater property. The subspecies has also been grown at the East Bay Regional Parks Botanic Garden at Tilden Regional Park in Berkeley since 1970, and introduced to Brannan Island SRA, Point Reyes National Seashore, and Brown’s Island in the Delta. Of these sites, the primrose persists only at Tilden Regional Park and Brannan Island. ! %&' ( )* ) # + 0 500 1000 1500 2000 2500 Peak Count 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 Year Stamm Sardis PG&E West PG&E East Comprehensive Conservation Plan 31 Refuge and Resource Description The primrose is a short-lived perennial, with some individuals persisting for several years. Arnold (pers. com. 1999) believes that bees are the primary pollinating agents at the Refuge. Although hawkmoths were not known on the dunes until 1983, they have been reported as pollinators of other Oenothera species. However, their role as primrose pollinators has not been documented. Studies are needed to determine the phenology and pollinators of this subspecies. Because the primrose prefers disturbed sites with nearly pure sand, it is vulnerable to nonnative weed encroachment. Greene (1995) found no primrose seedlings around mature primrose that were surrounded by nonnative weeds, yet seedlings were found near about 40 percent of mature primrose that were not surrounded by weeds. Greene determined that nonnative weeds compete with the primrose seedlings for water and light, resulting in reduced seedling germination and survival. Greene also determined that removing nonnative weeds around adult primrose enhanced germination rates. Weeds also have a negative impact on seedling germination success because they stabilize the dunes. Slowik (pers. com. 1999) confirmed the primrose’s need for regular disturbance by treatments on seedlings grown under cultivation. Slowik found that primrose seedlings germinated more readily in sand when the sand was disturbed and turned over. Factors that may limit primrose reproduction were investigated in 1993 by Pavlik and Manning. Although they identified low genetic variation and limited pollinators as potential factors limiting seed production, seed production was not considered a limiting factor for primrose reproduction. Pavlik et al. (1988a), Pavlik et al. (1993), and Pavlik and Manning (1993) also studied the seed bank dynamics, seed production, and seedling demography to assess the limitations on primrose growth. They found that more than half the ovules that were initiated failed to become seeds because effective pollinators were not available. Their work also indicated that substrate makeup and exposure were not critical to primrose seed germination, though competition with ripgut brome for light and moisture was. Although Antioch Dunes evening primrose USFWS Photo Table 1. General Trends for Refuge Endangered Species Species Population Status Current Threats Lange's Has generally been stable, peak counts in 1999 were the highest since surveys began in 1987. Despite this high, 1999 Stamm Unit counts were low as a result of a 1999 wildfire that swept through the unit Wildfire and nonnative weeds. primrose Natural populations of self-reproducing individuals have generally been declining since 1992. Nonnative weeds and lack of substrate disturbance. wallflower Cyclical, but generally stable. Nonnative weeds. 32 Antioch Dunes National Wildife Refuge Chapter 3 substrate makeup was not critical for seedlings to germinate, they found that primrose only reached reproductive maturity on sandy soils. Primrose produced many viable seeds, but seed output production over two years ranged from 26 percent to 37 percent of the maximum. Other factors, such as weather and predispersal seed predation, also contributed to lowered seed production, but lack of pollinators was believed to play a role. The Service has been conducting an annual primrose census to track population changes since 1985 (Figure 7). In an effort to reverse the decline in primrose populations, the Service began outplanting the primrose by collecting seeds from the Refuge, growing them in the Service nursery and contract nurseries, and planting the seedlings at the Refuge. Population Size and Status From 1984 to 1991, the total primrose population was estimated to range from 4,300 to 5,800 individuals. During this time, total primrose counts on the Refuge’s Stamm Unit were conducted every other year. During odd-numbered years, primrose numbers in the Stamm Unit were roughly estimated from transect counts. Figure 7 shows actual numbers of primrose counted during these years, odd numbered years are under-represented on the graph. In 1992, the Service observed a dramatic decline to 1,200 individuals and began outplanting primrose seedlings. Since then, a complete count of primrose has been conducted every year. In 1997, the primrose population reached a low of 455 individuals. This marked the eleventh year of general decline in the number of primrose at the Refuge since 1986. In 1998, the primrose population increased to 785 individuals, and the downward trend had ended. Primrose plantings in December 1997 were probably a bigger factor in this increase than natural reproduction. The steady decline of noncultivated primrose continues today. Nonnative weed encroachment continues to be the largest problem affecting the primrose (Table 1). Contra Costa Wallflower, Erysimum capitatum spp. angustatum Background The wallflower, an herbaceous plant in the Brassicaceae family, is a biennial or short-lived perennial; individuals die after setting seed in their second year. The wallflower was originally described in 1896 by E. L. Greene and modified in 1958 by George Rossbach. Like the primrose, the wallflower is endemic to the Antioch Dunes. The wallflower was listed as endangered in 1978. The entire known wild population of the wallflower exists at the Refuge and adjacent PG&E and Kemwater lands. Little is known about the reproductive phenology of the wallflower. Germination may occur in October, and leafing from October through December. Budding occurs in February, while flowering begins in March, peaking in April or May. A variety of different insect species have been observed visiting the plant and carrying pollen away with them. Fruiting begins in April and peaks in July. Seeds are wind-dispersed beginning in mid-May and peaking in September (Endangered Species Information System 1996). Contra Costa Wallflower USFWS Photo Comprehensive Conservation Plan 33 Refuge and Resource Description The wallflower grows in soil types classified as sand to sandy loam with a pH averaging 6.4 (range 5.6 to 7.0). Precise information about the species’ particular requirements is not known at this time. Service personnel have observed the wallflower growing in steep areas of unstable sand, especially on north-facing slopes immediately adjacent to the river (Service 1984). These slopes are generally not as densely vegetated and may enable the wallflower to compete more effectively for resources. Rossbach (1958) believed that the wallflower was restricted to stable dunes of fine sand containing some clay. The habitat was characterized as “sparse herbs and shrubs,” or less often pasture grasses, herbs, and scattered live oaks. Johnson (1978) suggested that reproducing individuals occurred primarily on uneven sites (i.e., river front bluff faces and edges). Although current populations of wallflower at the Refuge seem to be concentrated on steep, north-facing slopes by the river, wallflower at one time grew on flat terrain in an excavated area within the dunes on the Kemwater property (Figure 4). Today there are individual plants growing 160 to 660 feet away from the river bank in a flat hard pan area of the Refuge. In these areas the hard pan has been broken and the loose, sandy soil below has been exposed. A large stand of wallflower is found on the East PG&E parcel adjacent to the Refuge. This stand is atop and over a ledge leading down to the San Joaquin River. Although their population is now self-sustaining, overall, the wallflower appears to be more physically restricted within the dunes than the primrose. Not much is known about wallflower pollinators except that they are bees that nest in open banks. Unlike other Brassicaceae, which are typically pollinated by specialized insects, the wallflower does not require a specific pollinator. 0 1000 2000 3000 4000 5000 6000 Total Count 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 Year Stamm Sardis PG&E East PG&E West ! ,& # # + 34 Antioch Dunes National Wildife Refuge Chapter 3 The wallflower is grown at the Botanic Garden at Tilden Regional Park. It was found to be the most adaptable of the wallflowers cultivated. Unlike the primrose, the wallflower apparently may not require sandy soil, at least not in cultivation. Although the wallflower is endangered, it has been doing fairly well on the Refuge, propagating on its own. After the wallflower was planted in 1995, on dunes created in 1992 and 1993, it was self-propagating until nonnative weeds began to invade. Other than limited available habitat (wallflower seems to prefer north-facing slopes at the Refuge), nonnative weeds pose the only apparent significant threat to the wallflower. Population Size and Status In 1999, the population peaked at 11,567 individuals, the greatest number of wallflowers ever counted on the Refuge (Figure 8). It is possible that the increase in the number of mature plants was due to the influence of El Nino during the winter of 1997-98. Seeds that germinated that winter would have reached reproductive maturity in 1999 and germination or survival may have been higher than normal as a result of increased rainfall, although this has not been studied. Population survey results indicate that the total number of mature plants is highly variable year to year. Because wallflower is a biennial species, it would be expected to track yearly variation in weather and other environmental parameters much more closely than a longer-lived species. See Table 1 for a summary of trends for the three endangered species. $ - The management goals and objectives for each individual unit of the Refuge System vary. The Refuge System considers wildlife first when deciding whether to allow a public use. Public use at an individual 0 1000 2000 3000 4000 5000 6000 Total Count 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 Year Stamm Sardis PG&E East PG&E West ! .& / # + Comprehensive Conservation Plan 35 Refuge and Resource Description Refuge unit must be determined to be compatible with the specific Refuge’s purpose. Public access to the Refuge is restricted based on the sensitivity and limited distribution of the three endangered species. Refer to the Compatibility Determinations in Appendix A. Historically, the Antioch Dunes area and San Joaquin River were used for recreation such as biking, walking, sunbathing, fishing, picnicking, and swimming, while the upland areas were used for biking and walking. The Refuge is fenced and was closed to the public in 1986 to protect the endangered species and their habitat, a concern that arose as a result of several incidents. Visitors using the Refuge prior to this time commonly built illegal fires along the waterfront. On several occasions, the fires escaped and threatened the survival of the three species by indiscriminately burning surrounding habitat. In 1986, endangered plants were trampled by hundreds of people as they flocked to the Refuge to see a whale (nicknamed Humphrey) swim up the San Joaquin River. Although the Refuge is now closed to the public, volunteers help Refuge staff by participating in endangered species counts, wallflower and primrose plantings, picking up trash, and weeding. Occasional interpretive tours are also given to various groups, such as the local Sierra Club chapter or community college groups. Despite boundary signs and perimeter fences around both the Sardis and Stamm Units, unauthorized use of the Refuge continues. Unauthorized visitors have been seen fishing at the Refuge and evidence of numerous illegal camps have been found. Several parties have easements on the Refuge including: Contra Costa County has an easement for roadway slope and drainage affecting the southern ten feet of the Refuge, which adjoin Wilbur Avenue. The City of Antioch has an easement and right-of-way for two underground outfall sewer pipelines. Georgia-Pacific has easements for roadway, water, gas, oil, and sewer pipelines, and associated facilities. + Early Spanish explorers mentioned encountering Native American villages in the Antioch area. According to Davidson (1907), the diary of the 1772 expedition led by Lt. Fages and Padre Crespi refers to camping at a Native American village thought to be near the site of present-day Antioch. According to Padre Font, who accompanied Captain de Anza’s 1776 expedition, the Anza expedition visited a Native American village on the site of Antioch. The village was “situated in the plain a little before the sierra (translated from Spanish in Font’s diary to “oak ridge”) toward which we were going, and so close to the water that from it to the huts it could not have been a dozen steps” (Bolton 1933). Abella, Fages, Font, and other explorers in the late 1700s and early 1800s mentioned large numbers of deer, antelope, tule elk, and beaver. The abundance of game, oak, and other foodstuffs, and proximity to water were undoubtably key features attracting human settlers to the Refuge site. As in many other Native American settlements, European contact in the early 1800s caused a swift decline in the local Native American community, primarily through introduced diseases. 36 Antioch Dunes National Wildife Refuge Chapter 3 Settlement of the Antioch area by persons of European descent began in 1836 and continued in various forms of residence, agriculture, industry, grazing, and recreation through the present day. Establishing the Refuge in 1980 halted economic uses of the Refuge area including sand mining and farming. Any evidence of earlier human activity in the Refuge area has been obliterated by sand mining that began in the 1890s and continued through the twentieth century. The former sand quarry remains as witness of human impact on the landscape. Fragments of old bottles and ceramics were seen in a small portion of the Stamm Unit in 1999. These fragments may indicate that a portion of the sand quarry was back filled with household garbage. Further investigation is warranted to determine if these items hold any historical significance (Valentine pers. com. 2000). ' - The Refuge and surrounding lands have been used for industrial and recreational purposes. Throughout the years, agricultural and industrial use has been intense. Since the mid-1800s, the area has been used as a dairy farm, vineyard, brick factory, sand mine, docking facility, and a tavern site. Today, the Georgia-Pacific gypsum plant separates the Stamm and Sardis Units. Because the area had been one of the few sites for river access in the Antioch vicinity, it was historically a popular site for fishing, swimming, and sunbathing. The Service actively manages for the three endangered species using a variety of measures that are outlined in this section. Habitat management for the primrose, wallflower, and buckwheat is labor intensive and includes annual surveys, nonnative weed control, prescribed burning, importing sand, and revegetation. Emphasis is on adaptive management; monitoring the effects of management actions on endangered species populations and habitat health, and adjusting as necessary. Annual Surveys Populations of the three endangered species are surveyed annually to determine their status, prioritize management efforts, and analyze the effects of various management prescriptions by specific Refuge MA (Figures 3 and 4). Recent surveys have documented fairly healthy wallflower and Lange’s populations, but have shown low rates of primrose natural regeneration (See Figures 6, 7, and 8). Thus, propagation efforts over the past few years have focused on the primrose. The 2001 survey densities for the primrose, wallflower, and Lange’s are shown in Figures 9 and 10. Nonnative Weed Control Although a number of weedy species are found at the Refuge, the recent arrival of yellow starthistle has caused the most habitat degradation. Various weed control methods have been used at the Refuge including hand weeding, treating with herbicide, and prescribed burning. A series of experimental plots were developed to test the response of nonnative weeds to burning, flaming, broad-spectrum herbicide (Roundup®), grass-specific herbicide (Poast®), pre-emergent herbicide, a more specific herbicide (Transline®), and mowing. Early results indicate that HARDPAN #2 SCARIFIED TRIANGLE HARDPAN #1 NORTH EAST HARDPAN #3 SOUTH OF PATH EAST PLATEAU RESTORED VINEYARD HARDPAN #4 PLATEAU 1995 DUNES ACCESS ROAD ENTRY CAR BODY HARDPAN SLOPE RIVER SLOPE TRIANGLE SECTION TO OAK BLOWOUT VINEYARD PLATEAU RIVER HARDPAN #2 SCARIFIED TRIANGLE HARDPAN #1 NORTH EAST HARDPAN #3 SOUTH OF PATH EAST PLATEAU RESTORED VINEYARD HARDPAN #4 PLATEAU 1995 DUNES ACCESS ROAD ENTRY CAR BODY HARDPAN SLOPE RIVER SLOPE TRIANGLE SECTION TO OAK BLOWOUT VINEYARD PLATEAU RIVER HARDPAN #2 SCARIFIED TRIANGLE HARDPAN #1 NORTH EAST HARDPAN #3 SOUTH OF PATH EAST PLATEAU RESTORED VINEYARD HARDPAN #4 PLATEAU 1995 DUNES ACCESS ROAD ENTRY CAR BODY HARDPAN SLOPE RIVER SLOPE TRIANGLE SECTION TO OAK BLOWOUT VINEYARD PLATEAU RIVER 0 1 - 25 26 - 100 101 - 250 > 250 0 1 - 25 26 - 80 81 - 120 > 120 0 1 - 10 11 - 20 21 - 80 >80 Contra Costa Wallflower Lange's Metalmark Butterfly Antioch Dunes Evening Primrose 500 0 500 1,000 Feet CA/NV Refuge Planning Office - May 2002 I Figure 9. Stamm Unit Densities (no./acre) Based on 2001 Counts - Antioch Dunes National Wildlife Refuge PIT FLOOR WEST SOUTH OF CABLES SOUTH PLATEAU 1995 1992 DUNES EAST OF CORRIDOR PLATEAU 1995 DUNES 1993 DUNES RIVER FLAT WEST OF CORRIDOR PLATEAU SOUTH SLOPE WEST SLOPE EUCALYPTUS HILL CORRIDOR NORTH OF TOWER ACCESS ROAD SLOPE 1992/1993 NEW DUNES RIVER CREST DOMTAR TOWER NORTHWEST SLOPE SOUTHWEST CORNER SLOPE SMALL INNER HILL NORTH AND EAST OF TOWER KEMWATER RIVER CREST TRIANGLE NORTH SLOPE EAST SLOPE NORTH SLOPE (PG&E) PG&E Land Sardis Unit PG&E Land PIT FLOOR WEST SOUTH OF CABLES SOUTH PLATEAU 1995 1992 DUNES EAST OF CORRIDOR PLATEAU 1995 DUNES 1993 DUNES RIVER FLAT WEST OF CORRIDOR PLATEAU SOUTH SLOPE WEST SLOPE EUCALYPTUS HILL CORRIDOR NORTH OF TOWER ACCESS ROAD SLOPE 1992/1993 NEW DUNES RIVER CREST DOMTAR TOWER NORTHWEST SLOPE SOUTHWEST CORNER SLOPE SMALL INNER HILL NORTH AND EAST OF TOWER KEMWATER RIVER CREST TRIANGLE NORTH SLOPE EAST SLOPE NORTH SLOPE (PG&E) PG&E Land Sardis Unit PG&E Land PIT FLOOR WEST SOUTH OF CABLES SOUTH PLATEAU 1995 1992 DUNES EAST OF CORRIDOR PLATEAU 1995 DUNES 1993 DUNES RIVER FLAT WEST OF CORRIDOR PLATEAU SOUTH SLOPE WEST SLOPE EUCALYPTUS HILL CORRIDOR NORTH OF TOWER ACCESS ROAD SLOPE 1992/1993 NEW DUNES RIVER CREST DOMTAR TOWER NORTHWEST SLOPE SOUTHWEST CORNER SLOPE SMALL INNER HILL NORTH AND EAST OF TOWER KEMWATER RIVER CREST TRIANGLE NORTH SLOPE EAST SLOPE NORTH SLOPE (PG&E) PG&E Land Sardis Unit PG&E Land 0 <25 26 - 100 101 - 250 > 250 0 <25 25 - 80 81- 120 > 120 0 <10 10 - 20 21 - 80 >80 Contra Costa Wallflower Lange's Metalmark Butterfly Antioch Dunes Evening Primrose 500 0 500 Feet CA/NV Refuge Planning Office - May 2002 I Figure 10. Sardis Unit and PG&E Property Densities (no./acre) Based on 2001 Counts - Antioch Dunes National Wildlife Refuge 38 Comprehensive Conservation Plan 39 Refuge and Resource Description nonnative weeds do respond to these techniques to varying degrees. Poast®, a grass-specific herbicide, has been effective in controlling Bromus. Except for flaming, other treatments (including Transline®) have also been effective at controlling Bromus. Treating starthistle with Transline® provided excellent control. Starthistle also responded to flaming before seed set and responded to burning and somewhat to mowing. Because Transline® also killed buckwheat (Rusmore 1999), it cannot be used in areas with buckwheat stands. In 1997, the Service prepared an EA for the Prescribed Burn Program for the Refuge (Service 1997b). The Refuge then conducted its first prescribed burn in 1997 and burned about 12 acres total, divided among the Triangle MA and a portion of the Restored Vineyard MA of the Stamm Unit, and the South Plateau MA of the Sardis Unit, areas dominated by nonnative weeds (Figures 3 and 4). The goal was to burn these areas for three consecutive years to kill the nonnative weeds and reduce their seed bank. Persistent starthistle was spot treated with Roundup®. As of 1999, these areas had been burned for three consecutive years and were recently replanted with native vegetation. Two other Refuge MAs, Hardpan 1 MA and the remainder of the Vineyard MA, were added to the burn program in 1999 and were burned for three consecutive years. The burned areas showed promising though mixed results. Primrose and other native plants within the Triangle MA of the Stamm Unit responded positively. Starthistle has been effectively controlled through three years of prescribed burning. Unfortunately, other nonnative weeds like filaree and vetch moved into the burned areas quickly (Rusmore 1999). Vetch is currently being controlled with herbicide. Continuing research efforts in nonnative weed control will enable the Refuge to determine the most effective method to control nonnative weeds. Methods that are effective will continue to be implemented (Fernandez 1997, Rusmore 1999, Loredo pers. com. 2000). The Refuge will continue to burn areas that are dominated by nonnative weeds (Fernandez 1997), unless other methods are determined effective. Only areas that do not support many Lange’s will be considered for the program. In addition, small firebreaks will be constructed around any individual primrose or wallflower in the proposed burn areas. This will minimize effects to endangered species (Appendix J). Hand weeding and mowing also continue to be important tools in controlling weeds to promote native plant growth, particularly the primrose. Each of the endangered species on the Refuge are dependent on an open sand dune environment. To stabilize and increase their populations, management actions must continue to recreate this environment to the extent possible. Importing Sand New dunes were created by the Service, with the help of PG&E, by using imported sand. The first major dune restoration effort began in 1991. To create new dunes on the Refuge, PG&E donated, hauled, and contoured native riverine sand from a stockpile at a power plant formerly owned by PG&E located about one mile from the eastern boundary of the Refuge. The dunes were contoured to mimic the historic dunes and were then planted with nursery-grown endangered and native plants endemic to the Refuge. Nonnative weeds were hand-pulled and sprayed with herbicide to prevent encroachment on the 40 Antioch Dunes National Wildife Refuge Chapter 3 Constructing dunes using existing sand. USFWS Photo newly restored site. The dune restoration was continued for an additional year. Three dunes were created in the Sardis Unit and one in the Stamm Unit. Overall, about 7,000 cubic yards of sand (Morton pers. com. 2000) were imported and thousands of buckwheat, primrose, and wallflower were established on the new dunes in an attempt to create an open sand dune environment similar to conditions prior to sand mining. Buckwheat and Lange’s have persisted on these created dunes, however, primrose and wallflower are found only in small numbers on these dunes, if at all. As has happened on most of the Refuge, nonnative weeds have heavily colonized the restored dunes, and are probably outcompeting the endangered species (Fernandez 1997). Dunes created during this project can be identified in Figures 3 and 4 as 1992 Dunes, 1993 Dunes, and 1995 Dunes. Though these dunes were all created in 1991 and 1992, they are named for the year they were planted. In addition, there have been several recent dune construction projects on the Stamm Unit that have used existing substrate material. Using heavy equipment, existing sand was pushed up to form steep sided dune formations. In the fall of 1999, three dunes were recontoured in the Vineyard MA using a grant from Chevron Corporation. In February of 2000 an additional dune was constructed in the Northeast MA as part of a City of Antioch mitigation project. Caltrans provided labor for this project and constructed a fourth dune in the Vineyard MA. Revegetation The Service has propagated primrose, wallflower, and buckwheat in the past, and will add other sensitive native species to its propagation efforts in the future. During seed collection, no more than 5 percent of the seeds are collected from Refuge plants for propagation. These seeds are grown in a nursery during the fall for planting on the Refuge in the winter. Plants were grown in either the Refuge greenhouse, which had limited space, or contracted out to commercial nurseries. In 2000, the Service completed construction of an additional greenhouse to accommodate an increased quantity of endangered plant propagation. In the 1999-2000 season, the Service propagated and planted 835 primrose to augment the wild population (Loredo pers. com. 2000). Firebreaks The City of Antioch requires the Service to maintain a firebreak between the Refuge and the adjacent railroad tracks. The Refuge has tried scraping and discing to remove potentially flammable materials. Discing resulted in more nonnative weeds than had previously existed. Scraping (removing the top 1 to 2 inches of soil by scraping the soil surface with heavy equipment, such as a bulldozer with a blade), however, seemed to open up more habitat and allowed endangered species to resprout in greater numbers than prior to scraping (First Technical Panel 1999). The Service also established firebreaks within the Refuge to contain prescribed burns on the Refuge. Again, scraping proved to be more beneficial to endangered plants than discing (First Technical Panel 1999). Comprehensive Conservation Plan 41 Chapter 4 - Problems and Opportunities The Refuge was established to protect three endangered species. Maintaining sustainable populations of the three endangered species in a small area, while providing habitat for other plants and animals known to inhabit the dune ecosystem, presents a demanding challenge. A web of many interrelated and cumulative factors contribute to the problems of maintaining self-sustaining populations of the three endangered species. Many factors, including urban development, habitat fragmentation, and sand mining, have contributed to the decline of the species the Refuge was created to protect. Although numbers of the Lange’s and wallflower have fluctuated over the past 10 years (Figures 6, 7, and 8), their popula-tions overall have increased. However, primrose numbers have declined in the last 10 years. There were 5,800 mature primrose in 1984, and only 963 mature primrose in 1996, a decrease of 83 percent. The main prob-lem affecting the primrose and wallflower is nonnative weeds. Other potential problems include lack of suitable substrate, lack of insect pollinators, inadequate land base, and predation. Planning staff, the technical panel, and other key contacts identified problems plaguing the Refuge’s endangered species and other re-sources. The problems are described below and are grouped into general categories. Although the divisions can seem arbitrary, catego-rizing the problems make them easier to understand. Dune Habitat Loss of habitat, primarily through sand mining and industrial develop-ment, was a key factor in the decline of the endangered plants on the Refuge. Early industrialization and agricultural conversion (vineyards and grazing) contributed to the destruction of habitat. The dune habitat has been altered by sand mining which leveled the mined areas. His-torical records corroborate that the dunes probably consisted of upland vegetation with a few patches of sandy habitat that formed in eroded portions on the river side of the dunes. Since the former two-mile dune system has been reduced to the narrow extent of the Refuge, there is no longer enough riverfront property to sustain endangered species habitat at historic levels (Arnold et al. 1983). Problems related to dune habitat include: � Lack of ecosystem function, � Lack of native plant diversity, � Loss of habitat, 42 Antioch Dunes National Wildife Refuge Chapter 4 � Fragmentation and associated problems (i.e. decreased genetic diversity), and � Decreasing populations and species diversity of native insects, reptiles, mammals, and birds. Nonnative Weeds The major threat to the primrose, wallflower, and other native species, are nonnative weeds such as yellow starthistle and ripgut brome. Non-native weeds lead to lower germination and seedling survival rates and have been identified as the leading problem for endangered species and the dune ecosystem habitat at Antioch Dunes. The problems caused by, and associated with, nonnative weeds are complex and interrelated. Nonnative weeds not only outcompete natives for sunlight, moisture, space, and nutrients, but they also stabilize what little remains of the dunes. Primrose evolved on shifting, windblown riverine sand dunes and appears to thrive with a certain amount of disturbance. Unfortunately, the soil stabilization provided by nonnative weeds prevents the dunes from shifting, increasing competition for resources and posing a significant problem to those species requiring open sandy substrate for survival. In general, nonnative weeds affect the primrose and wallflower in a similar manner. Nonnative weeds can affect Lange’s indirectly by affecting the buckwheat. Nonnative weeds on the Refuge form dense stands, areas Lange’s avoid. Lange’s use the native buckwheat for egg-laying sites and nectar sources. Without a sufficient number of buck-wheat plants at the appropriate density, the butterfly population will not be supported. The first technical panel (1999) hypothesized that excessive nitrogen in the soils might limit the reproductive success of the primrose, wall-flower, and buckwheat. Increased nitrogen can promote nonnative weeds, while too little nitrogen can inhibit primrose, wallflower, and buckwheat reproduction. Factors that contribute to increased nitrogen include accumulated biomass, herbicide application (herbicides can increase the nitrogen load in the soil), and prescribed burning. In 1999, a soil survey conducted at the Refuge investigated differences in soil conditions between areas that supported healthy populations of prim-rose, wallflower, and buckwheat (population sites) versus areas that did not support these species but instead were dominated by nonnative weeds (control sites) (Jones and Stokes 2000). The survey found no significant difference in soil nitrogen levels between the two types of sites. Instead, soil from population sites was found to be significantly lower in percent of organic matter and phosphorus compared to soil from control sites. Thus, the three species are adapted to less fertile, rapidly permeable soils, presumably where they can outcompete nonna-tive weeds. Nonnative weeds also lead to lower native plant diversity. Decreased plant diversity leads to lower insect diversity. Maffei (1997) correlated weeds stabilizing sand with a decline in insect diversity. He observed 30 species of velvet ants in 1995 and only six in 1997. Similar declines were seen for other insects. Lower insect diversity can ultimately lead to a decrease in pollinators, which can lead to a decrease in the endangered species populations (Second Technical Panel 1999). Comprehensive Conservation Plan 43 Problems and Opportunities Disturbance Primrose, wallflower, and buckwheat, have different tolerances to disturbance. Primrose requires some level of disturbance and responds well to prescribed burns, firebreak scraping, and weed pulling in close vicinity to a plant. Wallflower prefers steep north-facing slopes which receive natural disturbance through erosion. Lange’s and buckwheat do respond favorably to disturbance. Lange’s can be immediately nega-tively impacted by disturbances such as burns and scraping, and healthy buckwheat populations can be found in areas with little disturbance. However, Lange’s prefers buckwheat in various successional stages and some disturbance may be necessary to provide this range. However, when planning disturbance of Lange’s habitat, the short-term negative effects to Lange’s must be considered. Disturbance will not be con-ducted in areas supporting substantial numbers of Lange’s, where the short-term negative effects may outweigh the long-term benefit. The varying tolerances and disturbance needs of the three species pose management problems. Predation Several predation problems were identified for the three endangered species within the approved Refuge boundaries. Mammals Mammals have been known to eat primrose (Second Technical Panel 1999). Although the specific predator has not yet been identified, it is presumed to be a subterranean animal, probably a rodent. This preda-tor eats roots, leaving primrose severed at the tap root, killing the plant. There has also been evidence of mammals eating the above ground portions of the plant (Loredo pers. com. 2000a). Insects Powell (1999) has identified three insect predators for the primrose. One is the Mompha murtfeldtella, a moth that feeds on growing tips but does not seem to limit the primrose’s ability to be self-sustaining. Another moth, Mompha eloisella, grazes in the interior of primrose stems, but also does not have a major effect (Powell 1992). However, Altica sp., a leaf eating beetle, reduces plants to skeletons in early summer, and does present a potential threat to the sustainability of the primrose population. The wallflower is also a host plant for three herbivorous insects, Chalceopla simpliciella, a moth that feeds on immature wallflower seeds and later is believed to feed on new wallflower leaves, Calcus sp., a moth that lays eggs on the wallflower, and Plutella xylostella, an external feeder whose larvae have been found on the wallflower (Powell pers. com. 1999). Problems Relating to Viable Seed Production The lack of pollinators for the primrose has been discussed in at least two papers, Pavlik et al. (1993), and Pavlik and Manning (1993), and at a technical panel (1999). Although seed production in the primrose is high, indicating that the primrose is being adequately pollinated, a lack of pollinators may contribute somewhat to its decline in the future. Primrose are primarily pollinated by bees. Other species of primrose 44 Antioch Dunes National Wildife Refuge Chapter 4 have been known to be pollinated by a hawkmoth, although there are no documented cases of the Antioch Dunes evening primrose being polli-nated this way. Factors related to the lack of viable seed production are complex. Low insect diversity is a contributing factor to the decrease in pollination. Low native plant diversity is a likely cause of low insect diversity and a decrease in pollinators. Greene (1995) and Thompson (1997) have also conducted research into the effect of low plant genetic diversity on seed viability and have found that the lack of genetic variability in the prim-rose likely leads to a decrease in seed viability. Wildlife Historically, the Refuge was home to the western toad, western rattle-snake, coast horned lizard, western fence lizard, side-blotched lizard, California legless lizard, glossy snake, racer, and gopher snake. How-ever, few reptiles have been seen in recent years. For example, the last horned lizard was seen in 1933. The lack of reptile diversity on the Refuge could possibly be attributed to the lack of native vegetation and loose sand, and destruction of habitat throughout the area. Further-more, the range of the dunes has become limited and fragmented after a long history of extreme disturbance. Human Disturbance At the first technical panel meeting (1999), human disturbance, such as wildfire, foot, bike, and motorcycle trespassers, was identified as a problem on the Refuge. Disturbance destroys plants growing in the immediate area of the disturbance. Even habitat management can result in individual trampling. However, the primrose repopulates the area quickly if the disturbance is not too frequent or repeated. It is possible that some walking-related disturbance may be beneficial, even necessary, to the primrose and other plant species native to dune sys-tems that are adapted to natural disturbances such as strong winds, shifting dunes, or river erosion. However, uncontrolled human presence can cause undesirable impacts to the Refuge, such as litter, trampling threatened and endangered species, wildfires, and vandalism. A lack of staff presence at the Refuge and insufficient law enforcement patrols result in more incidences of trespassing and vandalism. Wildfires All fires not classified as prescribed fires are wildfires. Unlike pre-scribed burns, wildfires are uncontrolled. Therefore, wildfires can be extremely destructive to endangered species. Lange’s, in particular, takes many years to recover from wildfires since fires tend to kill all larvae or destroy eggs (depending on the timing). Also, areas support-ing healthy populations of endangered plants could be damaged by wildfires. When planning prescribed burns, on the other hand, areas are carefully chosen to minimize effects to endangered species. Wildfires set by trespassers or escaping from adjacent properties have negatively affected the endangered species and other native habitat on the Refuge. For example, Refuge Officer Barry Tarbet and Service fire crew leader Chuck Berner conducted a site visit to investigate the cause and origin of the May 1999 wildfire. They surveyed the entire riverfront Comprehensive Conservation Plan 45 Problems and Opportunities and fire boundary and found evidence that the wildfire was started at the river by a trespasser’s campfire. The 10-acre wildfire spread through the northeastern portion of the Stamm Unit, burning the entire Blowout MA of the Refuge (Figure 3). The Blowout MA had previously provided excellent Lange’s habitat. Because the Lange’s spend their larval phase in the lower leaves of the buckwheat, it is likely that the entire population of Lange’s throughout the burn area perished. Many
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Antioch Dunes National Wildlife Refuge Comprehensive Conservation Plan

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