Antioch Dunes National Wildlife Refuge Draft Comprehensive Conservation Plan and Environmental Assessment

              dRAFT ¢OMPREHENSIVE ¢ONSERVATION PLAN
PLAN AND eNVIRONMENTAL aSSESSMENT
U.S. Fish & Wildlife Service
Antioch Dunes
National Wildlife Refuge
Antioch Dunes
National Wildlife Refuge
Draft Comprehensive Conservation Plan
Prepared By
U.S. Fish and Wildlife Service
California/Nevada Refuge Planning Office
2800 Cottage Way, W-1916
Sacramento, CA 95825
September 2001
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Table of Contents
Acronyms and Definitions iii
Scientific Names iii
Chapter 1 - Introduction 1
Introduction 1
Purpose and Need for the Plan 1
The U.S. Fish and Wildlife Service and National Wildlife Refuge System
U.S. Fish and Wildlife Service Responsibilities
The National Wildlife Refuge System
Legal and Policy Guidance
Antioch Dunes National Wildlife Refuge
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
Other Agencies
Chapter 2 - The Planning Process 13
The Planning Process 13
Issues 14
Chapter 3 - Refuge and Resource Description 17
Management Area Designations 17
Ecoregion Setting 17
Geographic and Physical Setting 17
Topography 17
Geology 20
Soils 20
Climate 20
Air Quality 21
Contaminants 22
Hydrology 22
Water Supply 23
Vegetation 23
Wildlife 24
Fish 26
Invertebrates 26
Endangered Species 27
Lange’s Metalmark Butterfly 27
Antioch Dunes Evening Primrose 30
Contra Costa Wallflower 32
Public Use 34
Easements 35
Cultural Resources 35
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Draft Comprehensive Conservation Plan and Environmental Assessment
ii Antioch Dunes National Wildlife Refuge
43
44
Land Use 36
Current Management Practices 36
Chapter 4 - Problems and Opportunities 41
Problems 41
Dune Habitat 41
Predation 43
Problems Relating to Viable Seed Production
Wildlife
Human Disturbance 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 63
Chapter 7 - Monitoring and Evaluation 65
Chapter 8 - Compliance Requirements 67
References 68
Figures
Figure 1. Regional Map 4
Figure 2. Refuge Map 5
Figure 3. Management Areas with Acreages - Stamm Unit 18
Figure 4. Management Areas with Acreages - Sardis Unit 19
Figure 5. Three Main Habitat Types on the Refuge Map 25
Figure 6. Lange’s Metalmark Butterfly Survey Results 29
Figure 7. Antioch Dunes Evening Primrose Survey Results 31
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
Tables
Table 1. General Trends for Refuge Endangered Species 33
Table 2. Estimated Initial Capital Outlay to Implement the CCP 63
Table 3. Estimated Annual Cost to Implement the CCP 64
Table 4. Monitoring Methods 66
Nonnative Weeds 42
Disturbance_____________________________________________________________43
Appendices
Appendix A - Compatibility Determinations 73
Appendix B - Technical Panel 83
Appendix C - Environmental Assessment (EA) 87
Appendix D - Vascular Plant List 135
Appendix E - Birds Species List for Antioch Dunes National Wildlife Refuge 145
Appendix F - Fish Species Found Offshore of the Refuge 149
Appendix G - Insect List 153
Appendix H - Glossary of Terms 161
Appendix I - Fire Management Plan 173
Draft Comprehensive Conservation Plan and Environmental Assessment iii
Acronyms
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 stem buckwheat buckwheat
National Environmental Policy Act NEPA
Global positioning system GPS
Scientific Names
Oenothera deltoides howellii (e) Antioch Dunes evening primrose
Erysimum capitatum angustatum (e) Contra Costa wallflower
Apodemia mormo langei (e) Lange’s metalmark butterfly
Eriogonum nudum auriculatum naked stem buckwheat
Centaurea solstitialis yellow starthistle
Bromus diandrus ripgut brome
Vicia villosa varia and Vicia sativa nigra vetch
Lepidium latifolium pepperweed
Cortaderia selliana pampas grass
Arundo donax giant reed
Robinia psuedoacacia black locust
Nerium oleander oleander
Ailanthus altissima tree of heaven
Croton californicus Croton
Draft Comprehensive Conservation Plan and Environmental Assessment 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 Refuge
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, as well as 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 NEPA
review, if needed. The CCP will:
• Provide a clear statement of direction for the management of the Antioch Dunes
National Wildlife Refuge over 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 management of the Refuge 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.
• Provide long-term continuity of Refuge management.
• Provide a basis for operation, maintenance, and development budget requests.
Chapter 1 - Introduction
Antioch Dunes
Evening
Primrose and
Contra Costa
Wallflower
2 Antioch Dunes National Wildlife Refuge
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 the Service
shares this responsibility 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 National Wildlife 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., National Forests and lands
administered by the U.S. Bureau of Land Management), the Refuge System is
managed for the benefit of fish, wildlife, and plant resources and their habitats.
Operated and managed by the Service, it comprises more that 500 national wildlife
refuges with a combined area of more than 92 million acres. The majority of refuge
lands (approximately 77 million acres) are located in Alaska. The remaining 15
million acres are spread across the other 49 states and several island territories.
The mission of the National Wildlife Refuge System is “to administer a national
network of lands and waters for the conservation, management and, where
appropriate, restoration of the fish, wildlife and plant resources and their habitats
within the United States for the benefit of present and future generations of
Amercians” (16 USC668dd et seq.). The goals of the National Wildlife 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 and the
human role in the environment and to provide refuge visitors with high-quality, safe,
wholesome, and enjoyable 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 international treaties. Relevant
guidance includes the National Wildlife Refuge System Administration Act of 1966,
Chapter 1 - Introduction
Draft Comprehensive Conservation Plan and Environmental Assessment 3
as amended by the National Wildlife Refuge System Improvement Act of 1997,
Refuge Recreation Act of 1962, and selected portions of the Code of Federal
Regulations and 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
National Wildlife Refuge System Improvement Act of 1997, identified a new mission
statement for the Refuge System; established six priority public uses (hunting,
fishing, wildlife observation and photography, environmental education and
interpretation); emphasized conservation and enhancement of 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 on 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 National Wildlife Refuge System Improvement Act of 1997 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 of 1997 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
purposes of the refuge. 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 draft compatibility determinations for environmental
education, interpretation, wildlife observation and photography, and research
(Appendix A - Compatibility Determination). These will be finalized with the CCP.
The Antioch Dunes National Wildlife Refuge
Location
The Refuge is adjacent to the City of Antioch along the south shore of the San
Joaquin River in an area that was part of an expanse of riverine sand dunes (Figure
1). The site is in Contra Costa County. The Refuge consists of two disjunct parcels
Chapter 1 - Introduction
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
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Figure 1.  Location Map
¢a⁄nff rEFUGE PLANNING oFFICE - aUGUST 2001 I
CALIFORNIA
Area
Enlarged
10 5 0 10 20
4 Miles
Contra Costa Co.
Sacramento Co.
Lake
Alhambra
Sa n Jo aqu in Ri v e r
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, July 2001 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
5
6 Antioch Dunes National Wildlife Refuge
(Figure 2). The westernmost unit, called the 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/Sante Fe Railroad, and a city wastewater
treatment plant and transfer facility; and to the north by the San Joaquin River. The
easternmost unit is referred to as the Sardis Unit. It is bordered to the west by the
Georgia-Pacific gypsum plant; to the east by Kemwater North American Company
(Kemwater); to the north by the San Joaquin River; and to the south by Wilbur
Avenue.
Land Ownership
The approved Refuge boundary encompasses 67 acres, 55 acres of which are
owned by the Service. The additional 12 acres owned by PG&E, are part of the
same remnant dune ecosystem, and have been managed in the past (1985 to 1995)
by the Service under a cooperative agreement with PG&E. The
area includes remnant dunes, and riparian cover types. The
Service and PG&E are currently in the process of renegotiating
the cooperative agreement. Under the new agreement, it is
anticipated that the Service will conduct some management
activities, such as biological monitoring and weed control, on the
PG&E parcel. In the interim, PG&E has continued to allow
biological surveys to be conducted on their lands. This CCP will
only address management of lands owned by the Service.
Partnerships
The Refuge has benefitted from partnerships with several
entities and individuals. 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,
Center for Natural Lands Management, and many dedicated
volunteers and individuals.
Refuge Setting
The Refuge is in an area that was once part of a more expansive sand dune system.
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). A 1908 U.S. Geological Survey topographic map showed the
bulk of the dunes to be along a two mile stretch of the river, averaging approximately
one-sixth of a mile in width and totaling roughly 190 acres (Howard and Arnold
1980). 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, many of which were used to rebuild San Francisco after the 1906
Sardis Unit
Chapter 1 - Introduction
Draft Comprehensive Conservation Plan and Environmental Assessment 7
earthquake. 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, invasive nonnative
grasses and vegetation encroached on the sand dunes to crowd 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 Sand dunes are formed by winds blowing loose sand off the coastal
years ago strand habitat.
10,000 Horses, bison, camels, mastodons, and ground sloths live in the area.
years ago 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 Noriega.
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, sheep fold, and store are established in the dunes and
later a shipyard is built. 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
Kellogg, a founder of the California Academy of Sciences.
1889 Two brickyards are located in the Antioch Dunes.
1896 Wallflower is described by E. L. Greene.
1900 Tracks for the Atcheson, Topeka, and Santa Fe Railroad are laid
along the southern margin of the dunes. Spur lines into the sand
dunes facilitate the removal of sand and bricks.
Oak cord wood is being removed for sale.
Chapter 1 - Introduction
8 Antioch Dunes National Wildlife Refuge
Russian thistle (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; in later years, 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 operate in the dunes.
1930s The Stamm family acquires the western portion of 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 there for 33 years.
Insect collectors from all over the west continue investigating the
unique insect fauna and refresh themselves afterward in the Little
Corral Bar.
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. The
Antioch Dunes are designated as “critical habitat.”
Chapter 1 - Introduction
Draft Comprehensive Conservation Plan and Environmental Assessment 9
1977 Mildred Mathias and Lincoln Constance describe a state listed rare
plant, Mason’s lilaeopsis (Lilaeopsis masonii) collected from the dunes.
Arnold starts a capture-and-release population study to estimate the
number of Lange’s at the Refuge.
1978 The wallflower and the primrose are listed as endangered species.
The dunes are designated as “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 naked stem buckwheat
(buckwheat), host plant for the Lange’s, 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 as a result of trampling
of endangered species and 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.
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.
Chapter 1 - Introduction
10 Antioch Dunes National Wildlife Refuge
(Arnold et al. 1983, Arnold pers. comm. 1999; Howard and Arnold 1980; Loredo pers.
comm. 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 or wildlife which are listed as endangered species or
threatened species or plants . . . ” 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 (Fish and
Wildlife 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 the Recovery Plan for Three Endangered Species
Endemic to Antioch Dunes, California: the primrose, wallflower, and Lange’s. The
recovery plan describes the species and sets forth recommendations for their
management. The plan identified fuelbreak maintenance (a barrier of cleared land
intended to stop the spread of fire), public recreation, and nonnative vegetation 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;
Chapter 1 - Introduction
Draft Comprehensive Conservation Plan and Environmental Assessment 11
• propagating and planting buckwheat (host plant for the Lange’s), primrose, and
wallflower;
• rebuilding natural dune substrate and topography by adding sand;
• removing nonnative vegetation, including the vineyard;
• restricting public access to both the Stamm and Sardis Units; and
• developing interpretive and environmental education programs.
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 has not been available.
Other Agencies
Brannan Island State Recreation Area
Brannan Island State Recreation Area was established in 1962 by the California
Department of Parks and Recreation (DPR) and supports a self-sustaining
population of primrose (Riblet pers. comm 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.
Primrose were planted on “low dunes” of Brannan Island in 1969, by Knight, former
staff member of the Regional Parks Botanic Garden, as a possible solution to the
“grave threat sand mining posed” to populations at Antioch Dunes. Roof, director
emeritus of the botanic garden, was the inspiration behind Knight’s action to initiate
dispersal to remote dune areas suitable for primrose (Fish and Wildlife 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 locations in the Recreation Area have
not received any special protection. Interestingly, the new locations are not aligned
with the existing population and prevailing winds on the island, and 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. comm 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.
Chapter 1 - Introduction
12 Antioch Dunes National Wildlife Refuge
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 weed removal and outplanting, to maintain
their numbers.
Montezuma Wetlands
Montezuma Wetlands, near Collinsville, across the river from the Refuge, is a
wetland restoration project that demonstrates the beneficial reuse of dredge material.
The project will use dredge disposal material from the Federal channels of the
Oakland Harbor and the berths that are maintained by 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 rehandling facility where materials will
be washed and cleaned prior to sale and placement. Montezuma Wetlands offers a
potential source for clean sand (to restore dunes) in close proximity to the Refuge.
The project is being undertaken by private entities.
CALFED
CALFED, a consortium of stakeholders and State and Federal agencies, is in the
process of 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 protection and enhancement of 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.
Arnold conducted a captive breeding program for the Lange’s in the early 1980’s,
following the low counts. The program was discontinued after on e season because
habitat improvement was considered to be a more effective means of increasing the
Lange’s population (Arnold, pers. comm. 2001, Arnold 1985, Arnold 1981).
Chapter 1 - Introduction
Draft Comprehensive Conservation Plan and Environmental Assessment 13
Chapter 2 - The Planning Process
The Planning Process
The process followed for the development of this CCP was guided by the Refuge
Planning Chapter of the Fish and Wildlife Service Manual (Part 602 FW 2.1, Novem-ber
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; and finally,
• implementing the plan.
The CCP may be amended as necessary at any time under an adaptive
management strategy. Major revisions will require public involvement and NEPA
review if needed.
In a Federal Register Notice, dated December 30, 1998, the Service announced that
it was preparing a plan for the Refuge. The first planning update for the Refuge was
released in December 1998. This update 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 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. The planning update generated
no requests for a meeting and little controversy, so a public meeting was not held.
A technical panel was convened in February of 1999, to assemble the 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 (see Appendix B - Technical Panel).
The second planning update, released in 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, released in July 2000, discussed
the goals and objectives. The fourth planning update was released in July 2001.
This planning update announced the upcoming draft and informed the public about
how to comment on the draft.
Chapter 2 - The Planning Process
14 Antioch Dunes National Wildlife Refuge
This draft CCP and Environmental Assessment (EA; Appendix C) released in August
2001, has been distributed to Refuge partners, adjacent landowners, government
agencies, local jurisdictions, community groups, and private citizens. The public has
30 days from its release to provide comments. Please refer to the cover letter for
details on how to submit comments. The final CCP, and planning update are
scheduled for release in October 2001. The CCP will be implemented following the
signing of the documents.
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. The periodic review of the objectives and
strategies is an integral part of plan implementation, and management activities may
be modified if the desired results are not achieved. If minor changes are required,
the level of public involvement and National Environmental Policy Act (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 vegetation, public use,
trespassing, and wildfires.
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 invasive nonnative vegetation 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 weed control. An off
duty fireman could possibly oversee the refuge and provide a presence on the
Refuge.
Chapter 2 - The Planning Process
Draft Comprehensive Conservation Plan and Environmental Assessment 15
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 invasive nonnative plant species.
• Identify and develop techniques for successful restoration.
• Consult with experts in dune ecology, restoration, and invasive nonnative
vegetation.
• Explore methods of creating sand disturbances in dunes.
• Investigate effects of prescribed burning on air quality.
• 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.
• Public use - most are not compatible.
• Explore possible land acquisition, by fee title or easement.
• 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.
Chapter 2 - The Planning Process
16 Antioch Dunes National Wildlife Refuge
Draft Comprehensive Conservation Plan and Environmental Assessment 17
Chapter 3 - Refuge and Resource Description
Management Area Designations
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 (Figures 3 and 4).
Ecoregion Setting
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 composed of
about 750,000 acres of tidal marshland, shallow back swamps, farmland, and mu-nicipalities
(California Department of Fish and Game and the Service 1980). The
Refuge occupies a unique place within the ecoregion in that inland dunes are very
limited within the Delta, occurring only in the vicinity of the Refuge (CALFED 1999).
Geographic and Physical Setting
The Refuge is near the southwestern boundary of the Delta, about five miles up-stream
of the confluence of the Sacramento and San Joaquin Rivers. The Delta
covers 738,000 acres with hundreds of miles of interlaced waterways. The Delta is
the major collection point for water that serves two-thirds of California’s population
(California Department of Water Resources 1995).
Before the regulation of flows and the channelization of rivers, the Delta was charac-terized
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 spe-cies
of birds and mammals.
The 55-acre refuge, along with the 12 adjacent acres owned by PG&E, is virtually all
that remains of a unique system of riverside sand dunes that once reached heights
of 120 feet and stretched up to 5.6 miles along the southern bank of the San Joaquin
River east of Antioch (Roof 1969).
Beginning in the 1880s, Antioch Dunes pure sands were systematically mined for
use in brick making and construction. Much of the brick used to rebuild San Fran-cisco
after the 1906 earthquake came from Antioch Dunes. Today, the last rem-nants
of the dunes are surrounded by a shipyard, a gypsum plant, and a sewage
treatment plant and vary from zero to 50 feet high.
The Refuge currently exists as an isolated habitat surrounded by industrial develop-ment
(Service 1997b). The existing habitat has been highly disturbed by sand
mining and agriculture, which is reflected in extensive weediness and inability to
support healthy populations of native species.
Topography
The Stamm Unit terrain is characterized by rolling dunes that range from zero to 50
feet, as measured from the river water surface elevation. The Sardis Unit, which
Chapter 3 - Refuge and Resource Description
HARDPAN #2
RIVER SLOPE
SCARIFIED
TRIANGLE
HARDPAN #1
NORTH
EAST
HARDPAN #3
SOUTH OF PATH
EAST
PLATEAU
BLOWOUT
RESTORED VINEYARD
HARDPAN #4
ENTRY CAR BODY
PLATEAU
TRIANGLE SECTION TO OAK
1995
DUNES
HARDPAN SLOPE
2.63
4.14 1.18 2.65
3.58
2.33
2.50
1.56
7.08
2.88
2.80
0.20
2.19
3.43
1.19
1.36
S a n J o a q u i n R i v e r
Georgia-
Pacific
Gypsum
Plant
Fulton Shipyar d Road
Fulton
Shipyard
Wilbur Avenue
Burlington Northern / Santa Fe R.R.
Minaker Road
Figure 3. Management Areas with Acreages - Stamm Unit
Approved Refuge Boundary Management Areas
100 0 100 200 300 400 500 I
Feet
CA/NV Refuge Planning Office - August 2001
Note: All units are in acres.
18
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
SOUTHEAST
CORNER
SLOPE
SMALL INNER HILL
NORTH AND
EAST OF TOWER
RIVER
CREST
TRIANGLE
NORTH
SLOPE
S a n J o a qui 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
0.82
0.89
0.95
1.22
1.88
2.04
3.18 2.46 2.9
5.67
Figure 4. Management Areas with Acreages
100 0 100 200 300 400
Feet CA/NV Refuge Planning Office - Aug 2001 I
Approved Refuge Boundary Management Areas on PG&E Property Management Areas on USFWS Property
Note: All units are in acres
19
20 Antioch Dunes National Wildlife Refuge
ranges from 1 to 50 feet is located between two higher parcels owned by PG&E, that
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 (Ivette Loredo
pers. comm 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,
amounting to 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.
Geology
The aeolian (wind-blown) 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 accu-mulated
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 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 last deposits probably occurred 140,000
years ago (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.
Soils
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 aver-ages
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.
Climate
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 tem-perature
of 74° F. Average high temperatures in the area range from above 90° F in
Chapter 3 - Refuge and Resource Description
Draft Comprehensive Conservation Plan and Environmental Assessment 21
July, August and September to the mid 30° F in December and January. The hottest
recorded temperature is 114° F, and the lowest recorded temperature is 14° F.
Summer winds flow from the river from the west or northwest at an average of 10 to
20 mph.
Air Quality
The Antioch area has good air flow. The area is exposed to winds both from the
west and east, and the terrain provides little protection from the wind. 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 gener-ated
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 vehicu-lar
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 has permitting authority for sta-tionary
air pollutant sources in the region. The District regulates federally regulated
air pollutants, particulate matter, organic compounds, nitrogen oxides, sulfur dioxide
and oxides, carbon monoxide, hydrogen sulfide, ground level ozone, and acid depo-sition.
Air quality in Contra Costa County is generally good. Because the air quality moni-toring
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 non attainment 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 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. Invento-ries
of these sources have been prepared by the Bay Area Air Quality Management
District (BAAQMD 1999a and 1999b). Mobile air sources, including automobiles,
busses, and trucks contribute about 50 percent of the air pollutants and air toxins
(Richardson pers. comm. 2001) except for sulfur dioxide, which is primarily gener-ated
by petroleum refining and power plants (DeBecker pers. comm. 2001).
The Antioch area contains a large portion of the industrial sources of pollutants
within the 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
Chapter 3 - Refuge and Resource Description
22 Antioch Dunes National Wildlife Refuge
PG&E parcels and Sardis Unit are covered with a fine layer of gypsum. The gypsum
suspended in the air is also a concern for the health of Refuge staff and visitors.
Contaminants
The Service’s Denver Engineering Division contracted a contaminants survey of the
Refuge in 1999 (Clark and Witham 1999). Phase I of the survey included site recon-naissance,
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 contamination by
creosote, pesticides, and asbestos.
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 gypsum, the railroad, or the
City of Antioch 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 detec-tion
limits set by the analytical laboratories, except for a soil sample from 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 species, 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 (Stamm Unit, Figure 3). Chrysotile is a naturally
occurring 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 loca-tion
of the chrysotile, the chrysotile observed in the groundwater at these two sites
appears to be naturally occurring. Although the survey found no contaminant issues
that currently affect the Refuge, the report recommends that further contaminants
monitoring should concentrate on ground water monitoring along the eastern bound-ary
of the Sardis Unit (adjacent to the Kemwater Plant) and along the southern
boundary of the Stamm Unit (adjacent to the former sewer treatment plant).
Hydrology
The San Joaquin River forms the northern boundary of the Refuge. The Refuge’s
river frontage is about two-thirds of a mile long and is tidally influenced. 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 includes nonnative vegetation.
The San Joaquin River adjacent to the Refuge is affected by the saline conditions of
the ocean and flows at around 340,000 cubic feet per second. Tides in the area
cause water level fluctuations from about 3 feet above sea level at high tides to
about 2.2 feet below sea level at low tides during a typical 25-hour tidal cycle.
Groundwater beneath the Refuge is predominately influenced by the level of the
adjacent San Joaquin River. As the ocean tides raise and lower the surface eleva-
Chapter 3 - Refuge and Resource Description
Draft Comprehensive Conservation Plan and Environmental Assessment 23
tion of the river, the groundwater level fluctuates in response. Groundwater level is
approximately 15 feet below the surface at the Hardpan #1 site, 27 feet at the Re-stored
Vineyard site, and 17 feet at the Car Body Area at the Stamm Unit (Clark and
Witham 1999).
Water Supply
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 south-ern
boundary of the Stamm Unit. The Refuge is in the Contra Costa Water District.
Vegetation
Historic accounts of the Refuge indicate that oak-woodland was the primary vegeta-tive
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, trees falling, 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 ap-proved
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 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 embank-ment
at the river’s edge provides a narrow space for riparian vegetation. The ripar-ian
corridor has been altered and includes nonnative vegetation 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 separately described cover type) are
described by Sawyer and Keeler-Wolf (1995) as consisting 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 unguicalata),
California poppy (Eschscholzia calfornica), California croton (Croton californicus),
Grindelia (Grindelia sp.), deerweed (Lotus scoparius), telegraph weed (Heterotheca
Littoral zone
where Mason’s
lilaeopsis is
found.
Chapter 3 - Refuge and Resource Description
24 Antioch Dunes National Wildlife Refuge
grandiflora), California matchweed (Gutierrezia californica), and silver bush lupine
(Lupinus albifrons).
These native plants, which composed these “unique stands,” still exist on the Ref-uge,
mostly in areas that have had the least amount of sand mining or human degra-dation
or in areas that have been intensively managed. Fringe areas along the river
in the Stamm and Sardis Units are examples of unmined remnants that have con-centrated
native species (Service 1997b). The highest proportion of native species
on the Refuge, including the primrose, wallflower, buckwheat, croton (Croton
californicus), deerweed (Lotus scoparius), and many others (Appendix D - List of
Vascular Plant Species) have traditionally been found on the open dune area of the
Blowout (Stamm Unit, Figure 3). The Blowout Unit most represents the historical
ecology of the original riverine dunes including the original topography, sandy nutri-ent-
poor soils, and wind currents. The native plants in this area also seem to be
shorter and less robust, 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 plant populations that do not support the same invertebrate diver-sity
(see invertebrates section).
Prior to Refuge establishment, the areas with the highest concentration of nonnative
weeds were disced (turning large discs through the soil using heavy equipment)
annually (Powell 1983). This included the unmined southern portion of the Sardis
Unit, along with its mined-out pit. Some of these areas became almost entirely
nonnative, invasive vegetation. Because of this, the Refuge no longer uses discing
as a weed control measure. Nonnative species dominate some areas of the Refuge.
Primarily of concern are ripgut brome (Bromus diandrus), yellow starthistle (Centau-rea
solstitialis), vetch (Vicia spp.), and Russian thistle (Salsola tragus).
Wildlife
The Refuge provides important habitat for many types of wildlife, including mam-mals,
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 and burrows and dens of squirrels and fox are commonly
observed. Beaver have also been seen along the river’s edge.
In 1977, Papenfuss, then a graduate student at UC Berkeley, completed an inven-tory
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
Chapter 3 - Refuge and Resource Description
S a n J o a q u i n R i v e r
S h i p yar d R
d .
F u l t o n
Burlington Northern / Santa Fe R.R.
Wilbur Ave.
Minaker Rd.
100 0 100 200 300
Meters
CA/NV Refuge Planning Office - July 2001 I
Figure 5. Three main habitat types on the Refuge.
Approved Refuge Boundary Riparian Antioch Dunes Unique Stands (Sawyer, Keeler-Wolf 1995) Littoral Zone
25
26 Antioch Dunes National Wildlife Refuge
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. No
amphibians were found, however, historical collections for the Refuge include the
western toad.
Two California silvery legless lizard sightings occurred in 2000. Fence lizards have
also been seen on the Refuge recently as well as a gopher snake (Pituophis
melanoleucus) and racers (Coluber constrictor) (Loredo pers. comm. 2000b).
Numerous bird species have been observed on the Refuge, including migratory and
resident birds. Appendix E lists birds found at the Refuge. Gadwalls (Anas strepera)
and mallards (A. platryhynchos) have also been observed nesting on the Refuge
(Buffa pers. comm. 2001).
Fish
The Service’s Sacramento/San Joaquin Estuary Fishery Resource Office has moni-tored
fish populations in the San Joaquin River from a beach seining station on the
Refuge since 1979. The fish are sampled at the station monthly. Listed species
caught offshore of the Refuge include winter-run chinook salmon (Oncorhynchus
tshawytscha) (state and federally listed endangered), delta smelt (Hypomesus
transpacificus) (state and federally 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 sam-pling
station is included as Appendix F - Fish Species Found Offshore of the Refuge.
Invertebrates
Antioch Dunes has been known as an entomological hotspot since the 1930s when
entomologists began collecting in what is now the Sardis Unit. The area attracted
remarkable attention for its large and colorful species with desert affinities. In the
1930s, many species of wasps and flies, particularly the giant flower-loving fly
(Thaphiomydas 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 uncer-tain
status, and the eighth is Lange’s, discussed in the Endangered Species section.
J.A. Powell and associates conducted a survey of insects 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 to 1939 (extensive sand-mining),
1948 to 1954 (extensive industrial buildup), and 1976 to 1984 (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 1930’s 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, he suggests that
Chapter 3 - Refuge and Resource Description
Draft Comprehensive Conservation Plan and Environmental Assessment 27
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 1976-1982 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 1976-1982
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, invasive vegetation and lack of soil
disturbance (Powell pers. comm. 1999). Maffei noted this as well; in the 1995 Dune
area (Stamm Unit, Figure 3), an increasing loss of insect species occurred as the
nonnative vegetative cover increased with each successive season, resulting in
minimal sand movement (Maffei 1997, Maffei pers. comm. 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 G - Insect Species Found at
the Refuge.
Endangered Species
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 eight species that are Federal “species of concern” at
the Refuge, which have no protection under the Endangered Species Act: the San
Joaquin dune beetle (last seen in 1974 and probably since extirpated - species of
concern), the Antioch cophuran robberfly (last seen in 1939), Antioch efferian
robberfly, Antioch adrenid bee, Antioch mutilid wasp, Middlekauf’s shieldback katy-did,
the Suisun marsh aster, Mason’s lilaeopsis, and the delta tule pea. The Califor-nia
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 popula-tions
concentrated in the 1992 and 1993 Dunes at the Sardis Unit, and the Blowout
Chapter 3 - Refuge and Resource Description
28 Antioch Dunes National Wildlife Refuge
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, about 67 acres of suitable
habitat, constitutes the entire present range for the Lange’s.
Lange’s, like most other butterflies, has a close relationship with its larval food plant,
the buckwheat, and produces 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.
Female Lange’s lay eggs throughout the
adult flight period. The gray eggs are laid on
the stem axils of the lower half of the buck-wheat,
where the foliage is withered. They
are often deposited in clusters of two or four.
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 mid-summer in the litter
at the base of the buckwheat (U.S. Fish and
Wildlife Service 1984).
Powell found that adults of both sexes are perchers and are capable of long flights
between perches (US Fish and Wildlife 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 plant for egg-laying, and sufficient food for larvae (U.S. Fish
and Wildlife Service 1984). The highest density of buckwheat on the Refuge occurs
in open areas, where both nonnative ripgut brome and yellow starthistle, also occur.
Invasion by nonnative vegetation 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 nonna-tive
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 con-sumed
some Lange’s habitat, but the Lange’s has managed to regain their former
numbers. In 1999 a wildfire in the Blowout subunit of the Stamm Unit destroyed
some of the best Lange’s habitat. The buckwheat in this unit quickly resprouted, and
Lange’s
Metalmark
Butterfly
Chapter 3 - Refuge and Resource Description
© R.A. Arnold
Draft Comprehensive Conservation Plan and Environmental Assessment 29
Lange’s are beginning to move back into the area, presumably from adjacent units
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 docu-mented
a decline from more than 2,000 individuals to fewer than 400 reproducing
individuals (effective adult population number) (Arnold 1983a). He 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 the 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 docu-mented
a Lange’s population increase at both the Sardis and the 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 pers. comm).
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 (Fig-ure
6). Arnold captured, counted, and marked the Langes’ daily. He could distin-guish
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 (Aug-Sept) and uses the
highest count during those surveys as the year’s peak count, without distinguishing
Chapter 3 - Refuge and Resource Description
Figure 6. Lange’s Metalmark Butterfly Survey Results
0
500
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2000
2500
Peak Count
1986
1987
1988
1989
1990
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1996
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Year
Stamm Sardis PG&E West PG&E East
30 Antioch Dunes National Wildlife Refuge
between individuals that have already been counted (Arnold pers. comm. 2001). The
peak counts 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. They are different sampling methods that cannot be
directly compared (Parker pers. comm. 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 it
was recognized as a separate variety by Munz, and 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 State Recreation Area, 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.
The primrose is a short-lived perennial, with some individuals persisting for several
years. Arnold (pers. comm. 1999) believes that bees are the primary pollinating
agent 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 pollinators of the primrose 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 encroachment from nonnative weedy species. Greene (1995) found no primrose
seedlings around mature primrose that were surrounded by weed species, yet
seedlings were found near about 40 percent of mature primrose that were not
Antioch
Dunes
Evening
Prim-rose
Chapter 3 - Refuge and Resource Description
Draft Comprehensive Conservation Plan and Environmental Assessment 31
surrounded by weed species. Greene determined that nonnatives compete with the
primrose seedlings for water and light, resulting in reduced seedling germination and
survival. She 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. comm. 1999)
confirmed the primrose’s need for regular disturbance by treatments on seedlings
grown under cultivation. She 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 that limit 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 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 pre-dispersal seed
predation, also contributed to lowered seed production, but lack of pollinators was
believed to play a role.
Figure 7. Antioch Dunes Evening Primrose Survey Results
Chapter 3 - Refuge and Resource Description
0
1000
2000
3000
4000
5000
6000
Total Count
1984
1985
1986
1987
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1989
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Year
Stamm Sardis PG&E East PG&E West
32 Antioch Dunes National Wildlife Refuge
The Service has been conducting an annual census of the primrose to track changes
in the population since 1985 (Figure 7). In an effort to reverse the decline in
primrose populations, the Service began outplanting the primrose by collecting seed
from the Refuge, growing them in the Service nursery and contract nurseries, and
then planting seedlings at the Refuge.
Population Size and Status
From 1984 to 1991, the total primrose population was estimated to range from
4,300-5,800 individuals. During this time, total primrose counts on the Refuge’s
Stamm Unit were only conducted every other year. During odd-numbered years,
primrose numbers in Stamm were roughly estimated from transect counts. Figure 7
shows actual numbers of primrose counted during these years, therefore 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
11th year of general decline in the number of primrose at the Refuge since
1986. In 1998, the downward trend in the primrose population ended and
increased to 785 individuals. Primrose plantings in December 1997 were
probably a bigger factor in this increase than natural reproduction. The
steady decline of noncultivated primrose and primrose outplanting continues
today. Encroachment of nonnative vegetation continues to be the largest
problem affecting the primrose (Table 1).
Contra Costa Wallflower, Erysimum capitatum spp. angustatum
Background
The wallflower is an herbaceous plant in the Brassicaceae family and 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 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 number 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).
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 are 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 therefore may enable the wallflower to compete more
Chapter 3 - Refuge and Resource Description
Contra Costa
Wallflower
Draft Comprehensive Conservation Plan and Environmental Assessment 33
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 parcels adjacent to the Refuge. This stand is atop and over a ledge
leading down to the San Joaquin River. Currently the wallflower is found where
vegetative cover ranges from 50 percent to 100 percent. 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.
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 invasive vegetation began
to invade. Other than limited available habitat (wallflower seem to prefer north-facing
slopes at the Refuge), nonnative invasive vegetation 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 (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 1997/1998.
Table 1. General Trends for Refuge Endangered Species
Lange’s Wildfire and nonnative
invasive vegetation.
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.
primrose Natural populations of self-reproducing individuals
have generally been declining since 1992.
Nonnative invasive
vegetation and lack of
substrate disturbance.
wallflower Cyclical, but generally stable. Nonnative invasive
vegetation.
Chapter 3 - Refuge and Resource Description
Species Population Status Current Threats
34 Antioch Dunes National Wildlife Refuge
Seeds that germinated that winter would have reached reproductive maturity in 1999.
Seedling 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.
Wallflower is a biennial species, typically living only two years, thus, 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.
Public Use
The management goals and objectives for each individual refuge of the Refuge
System vary. The National Wildlife Refuge System considers wildlife first when
deciding whether to allow a public use. Public use at an individual Refuge unit must
be determined to be compatible with the specific Refuge’s purpose. At the Antioch
Dunes Refuge, 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
Chapter 3 - Refuge and Resource Description
Figure 8. Contra Costa Wallflower Survey Results
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Blooming Plant Count
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Stamm Sardis PG&E East PG&E West
Draft Comprehensive Conservation Plan and Environmental Assessment 35
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 numerous encampments have been found.
Easements
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 Gypsum Company has easements for roadway, water, gas, oil,
and sewer pipelines, and associated facilities.
Cultural Resources
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.
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
until the Refuge was established in 1980. Although extensive human activity is
known from the area, little evidence of this activity remains because of sand mining
that began in the 1890s and continued through the next century. Some more recent
Chapter 3 - Refuge and Resource Description
36 Antioch Dunes National Wildlife Refuge
cultural artifacts can still be found among what remains of the leveled dunes. Old
bottles and ceramic fragments were found in the Stamm Unit in 1999. It is presumed
that the Refuge was used as a de facto garbage dump during the period that the
Refuge was mined for sand (Valentine pers. comm. 2000).
Land Use
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 location for fishing, swimming, and sunbathing.
Current Management Practices
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, the host plant for the Lange’s, 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 subunit (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 1998 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 occur at the Refuge, the recent arrival of yellow
thistle has caused the most destruction. Various weed control methods have been
employed 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 invasive
species do respond to these techniques to varying degrees. Poast®, a grass-specific
herbicide, has been effective in controlling Bromus. Other treatments
(including Transline®) have also been effective at controlling Bromus, except
flaming. Treating starthistle with Transline® provided excellent control. Starthistle
also responded to flaming before seed set and responded to burning and somewhat
to mowing. However, Transline® also killed buckwheat (Rusmore 1999) and
therefore cannot be used in areas with buckwheat stands.
Chapter 3 - Refuge and Resource Description
HARDPAN #2
RIVER SLOPE
SCARIFIED
TRIANGLE
HARDPAN #1
NORTH
EAST
HARDPAN #3
SOUTH OF PATH
EAST
PLATEAU
BLOWOUT
RESTORED VINEYARD
HARDPAN #4
ENTRY CAR BODY
PLATEAU
TRIANGLE SECTION TO OAK
1995
DUNES
HARDPAN SLOPE
HARDPAN #2
RIVER SLOPE
SCARIFIED
TRIANGLE
HARDPAN #1
NORTH
EAST
HARDPAN #3
SOUTH OF PATH
EAST
PLATEAU
BLOWOUT
RESTORED VINEYARD
HARDPAN #4
ENTRY CAR BODY
PLATEAU
TRIANGLE SECTION TO OAK
1995
DUNES
HARDPAN SLOPE
HARDPAN #2
RIVER SLOPE
SCARIFIED
TRIANGLE
HARDPAN #1
NORTH
EAST
HARDPAN #3
SOUTH OF PATH
EAST
PLATEAU
BLOWOUT
RESTORED VINEYARD
HARDPAN #4
ENTRY CAR BODY
PLATEAU
TRIANGLE SECTION TO OAK
1995
DUNES
HARDPAN SLOPE
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
CA/NV Refuge Planning Office - July 2001 500 0 500 1,000 Feet I
Figure 9. Stamm Unit Densities (no./acre) Based on 1998 Counts
37
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
DOMT AR
TOWER
NORTHWEST
SLOPE
SOUTHEAST
CORNER
SLOPE
SMALL INNER HILL
NORTH AND
EAST OF TOWER
KEMWATER
RIVER
CREST
TRIANGLE
NORTH
SLOPE
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
DOMT AR
TOWER
NORTHWEST
SLOPE
SOUTHEAST
CORNER
SLOPE
SMALL INNER HILL
NORTH AND
EAST OF TOWER
KEMWATER
RIVER
CREST
TRIANGLE
NORTH
SLOPE
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
DOMT AR
TOWER
NORTHWEST
SLOPE
SOUTHEAST
CORNER
SLOPE
SMALL INNER HILL
NORTH AND
EAST OF TOWER
KEMWATER
RIVER
CREST
TRIANGLE
NORTH
SLOPE
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
CA/NV Refuge Planning Office - Aug 2001 500 0 500 Feet I
Figure 10. Sardis Unit Densities (no./acre) Based on 1998 Counts
38
Draft Comprehensive Conservation Plan and Environmental Assessment 39
In 1997, the Service prepared an EA for the Prescribed Burn Program for the Refuge
(US Fish and Wildlife Service 1997b). The Refuge then conducted its first
prescribed burn in 1997 and burned about 12 acres total, divided among the Triangle
Unit and a portion of the Restored Vineyard Unit of Stamm and the South Plateau
Unit of Sardis, areas dominated by nonnative invasive vegetation (Figures 3 and 4).
The goal was to burn these areas for three constructive years to kill the nonnative
weeds and reduce their seed bank. Persistent starthistle was spot treated with
Round-up®. As of 1999, these areas had been burned for three consecutive years
and were recently replanted with native vegetation. Two other Refuge units,
Hardpan #1 and the remainder of the Vineyard, were added to the burn program in
1999 and were also burned for three consecutive years.
The burned areas showed promising though mixed results. Primrose and other
native plants within the Triangle Area of the Stamm Unit responded positively.
Unfortunately, other nonnative weeds like filaree and vetch moved into the burned
areas quickly (Rusmore 1999). Vetch is currently being controlled with herbicide.
Starthistle has been effectively controlled through three years of prescribed burning.
Continuing research efforts in invasive
plant control will enable the Refuge to
determine the most effective method to
control invasive nonnative vegetation.
Methods that prove effective will continue
to be implemented (Fernandez 1997,
Rusmore 1999, Loredo pers. comm. 2000).
The Refuge will continue to burn areas that
are dominated by invasive nonnative
vegetation (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 (See
Appendix I - Fire Management Plan).
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 re-create
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. The Service imported
native riverine sand to create new dunes from a stockpile at a PG&E power plant
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 vegetation was
Chapter 3 - Refuge and Resource Description
Constructing
dunes using
existing sand.
40 Antioch Dunes National Wildlife Refuge
hand-pulled and sprayed with herbicide to prevent encroachment on the newly
restored site. The dune restoration was continued for an additional year. A total of
three dunes were created in the Sardis Unit and one in the Stamm Unit.
Overall, about 7,000 cubic yards of sand (Morton pers. comm. 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 vegetation has
heavily colonized the restored dunes, and are probably out-competing 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 Stamm that have utilized 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 area using a grant from
Chevron Corporation. In February of 2000 an additional dune was constructed in
Northeast as part of a City of Antioch mitigation project. CalTrans provided labor for
this project and, additionally, constructed a fourth dune in the Vineyard.
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 are grown either in 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. comm. 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 both scraping and discing to
remove potentially flammable materials. Discing resulted in more nonnative
vegetation 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 pers.
comm. 1999). The Service also established firebreaks internally to the Refuge to
contain prescribed burns on the Refuge. Again, scraping proved to be more
beneficial to endangered plants than discing (First Technical Panel pers. comm.
1999).
Chapter 3 - Refuge and Resource Description
Draft Comprehensive Conservation Plan and Environmental Assessment 41
Chapter 4 - Problems and Opportunities
Chapter 4 - Problems and Opportunities
Problems
The Refuge was established to protect three endangered species. Maintaining a
sustainable population of the three endangered species in a small area, while provid-ing
habitat for other plants and animals known to inhabit the dune ecosystem, pre-sents
a demanding challenge. A web of many interrelated and cumulative factors
contribute to the problems of maintaining self-sustaining populations of three endan-gered
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 (Tables 2, 3, and 4), their populations overall have increased. However, prim-rose
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
problem 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 plagu-ing
the Refuge’s endangered species and other resources. The problems are
described below and are grouped into general categories. Although the divisions
can seem arbitrary, categorizing the problems make them easier to understand and
grasp.
Dune Habitat
Loss of habitat, primarily through sand mining and industrial development, was a key
factor in the decline of the endangered plants present at the Refuge. Early industri-alization
and agricultural conversion (vineyards and grazing) have contributed to the
destruction of habitat. The dune habitat has been almost completely altered by sand
mining by effectively leveling the mined areas. Historical 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 2-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,
• Fragmentation and associated problems (i.e. decreased genetic diversity), and
• Decreasing populations and species diversity of native insects, reptiles,
mammals, and birds.
42 Antioch Dunes National Wildlife Refuge
Nonnative Weeds
Although considerable evidence indicates that the dunes were stabilized in historic
times with the “blowout areas” supporting the primrose, the major threat to the
primrose, wallflower, and other native species, is the invasion of nonnative
vegetation such as yellow starthistle and ripgut brome. Nonnative vegetation leads
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, invasive nonnative plants are
complex and interrelated. Nonnative vegetation not only out-competes natives for
sunlight, moisture, space, and nutrients, but it also stabilizes what little remains of
the dunes. Primrose has evolved on shifting, wind-blown riverine sand dunes and
appears to thrive with a certain amount of disturbance. Unfortunately, the soil
stabilization provided by nonnative plants 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, invasive nonnative vegetation affects the primrose and wallflower in a
similar manner. Nonnative vegetation affect Lange’s indirectly by affecting the
buckwheat. Invasive vegetation on the Refuge form dense stands, areas Lange’s
tend not to frequent. Lange’s uses native plants for egg laying and nectar sources.
Without a sufficient number of buckwheat 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, wallflower, and buckwheat.
Increased nitrogen can promote nonnative weeds, while too little nitrogen can inhibit
reproduction of the primrose, wallflower, and buckwheat. 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 was conducted at the Refuge to investigate differences in soil conditions
between areas that supported healthy populations of primrose, wallflower, and
buckwheat (population sites) versus areas that did not support these species but
instead were dominated by non-native 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 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 nonnatives.
Invasion by nonnative vegetation also leads 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 pers. comm. 1999).
Draft Comprehensive Conservation Plan and Environmental Assessment 43
Disturbance
Primrose, wallflower, and buckwheat, host for Lange’s, all 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 not particularly respond favorably to
disturbance. Lange’s can be immediately negatively 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 a this range. This must
be balanced by direct negative effects to Lange’s. The varying tolerances and needs
for disturbance of the three species poses 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 (Technical Panel 1999). Although the
specific predator has not yet been identified, it is presumed to be a subterranean
animal, probably a rodent. The predator eats roots, leaving primrose severed at the
tap root, effectively killing the plant. There has also been evidence of mammals
eating the above ground portions of the plant (Loredo, pers. comm. 2000a).
Insect Predators
Powell (1999) has identified three insect predators for the primrose. One is 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 (Powell, pers. comm. 1999) 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.
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 have been known to be pollinated by a hawkmoth, although there are no
documented cases of the Antioch Dunes evening primrose being pollinated this way.
44 Antioch Dunes National Wildlife Refuge
Factors related to 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
primrose likely leads to a decrease in seed viability.
Wildlife
Historically, the Refuge was home to the western toad, western rattlesnake, coast
horned lizard, western fence lizard, side-blotched lizard, California legless lizard,
glossy snake, fence lizard, racer, and gopher snake. However, few of the 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. Furthermore, 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,
habitat management, and foot, bike, and motorcycle trespassers, was identified as a
problem on the Refuge. Disturbance destroys plants growing in the immediate area
of the disturbance. 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 systems 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 of threatened and endangered species, wildfires,
and vandalism. A lack of staff presence at the Refuge and insufficient law
enforcement patrols result in higher incidences of trespassing and vandalism.
Wildfires
All fires not classified as prescribed fires are wildfires. Unlike prescribed 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 supporting healthy populations of endangered plants could be damaged
by wildfires. When planning prescribed burns, on the other hand, units are chosen
and care is taken 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 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 section of the Refuge (Figure 3). The Blowout had previously provided
Draft Comprehensive Conservation Plan and Environmental Assessment 45
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 native plant species, including croton and buckwheat,
have recovered well. However, fire-tolerant weeds, such as vetch and filaree, have
increased, competing with native plants.
External Factors
A number of external factors may also contribute to Refuge problems. The first
technical panel (1999) voiced concerns about the effect of surrounding land uses on
the Refuge, specifically, the effect of chemical uses on surrounding lands.
Pesticides, for example, have the potential to drift onto the Refuge, and also affect
potential pollinators on adjacent lands. Nonnative vegetation can expand from
adjacent properties onto the Refuge.
The Sardis Unit of the Refuge is located downwind of a gypsum plant. The leaves of
the plants at Sardis, especially those adjacent to the plant, are covered with a layer
of gypsum dust. It is unknown at this time what effect gypsum may have on soil
chemistry, photosynthesis, and other factors that affect plant growth, reproduction,
viability, and seedling survival.
Lack of Information
Lack of information is problematic for managing any refuge. Although an abundance
of data has been gathered at Antioch, some factors remain unknown. The list of
identified unknowns include:
• The effects of scraping, burning, and other management practices on insects.
Although prescribed burning seems to benefit the two endangered plants and the
host plant for the Lange’s by reducing weed populations, its effects on insects are
not fully known. Maffei conducted surveys following a controlled burn in 1997. The
insect composition along the scraped firebreak changed dramatically within a week
after the burn. Chrysidid wasps were fairly common on June 7, 1997 (ten specimens
found). By June 14, after the burn, only three individuals were found, with one
individual found on successive visits during the following three following weeks.
Conversely, the sand wasp, a host for one of the chrysidid wasps became very
common and was frequently observed constructing burrows in the loose sand (Maffei
1997). This topic merits additional study.
• The effect of lupine on endangered species. Some experts believe that the
nitrogen-fixing lupine might add to the nitrogen load of the soil, to the detriment of
the primrose. Others believe primrose do better in the vicinity of lupine (Thompson
1997).
• The effects of gypsum on plant growth and human health.
• The status and identity of endangered plant pollinators.
The Service recognizes the need to collect more data and is currently working on a
project to determine the most effective means of controlling nonnative invasive
vegetation. The Service will continue to encourage research by non-Service
scientists on the Refuge.
46 Antioch Dunes National Wildlife Refuge
Opportunities
Although there are considerable challenges facing the Refuge, it still ranks as a gem
of diversity, preserves endemic and listed species, and remains a remnant riverine
dune ecosystem. There are many opportunities to work with partners to preserve
endangered species habitat. The City of Antioch, with assistance from California
Department of Transportation (Caltrans), has worked with the Service to recontour a
dune, and will propagate and plant native species, and control nonnative vegetation.
Caltrans continues to be an important data-sharing partner and has provided the
Service with numerous aerial photographs of the Refuge, as well as labor for dune
construction. Chevron Oil Company has worked with the Refuge to recontour three
new dunes on the Refuge in the Restored Vineyard area. The Service and PG&E
are continuing to pursue a cooperative agreement on PG&E lands. The agreement
would improve habitat for endangered species, allow the Service and PG&E to
cooperatively manage the Sardis Unit as 27 acres of continuous habitat, and allow
the Service to conduct surveys and management activities on PG&E land.
Prescribed burns at the Refuge have dramatically reduced yellow starthistle densities
and have resulted in increased cover by native species, although some fire-resistant
weeds, such as vetch and filaree, have significantly increased. The Refuge is
actively controlling vetch with herbicide and hand-pulling, and will investigate filaree
control. At this point, the native plants seem better able to compete with filaree than
with yellow starthistle or ripgut brome. Thus, prescribed burning appears to be a
useful new tool in weed management on the Refuge.
The unique character of the Refuge has generated a great deal of interest and
valuable partnerships over the years. Faculty and staff from various universities and
colleges, and local experts continue to provide the Refuge with advice, new
information, and important research. The Service and several local universities have
conducted research on the Refuge for many years. There are opportunities to
analyze data that has been collected, incorporate research results, and develop
adaptive management strategies.
Prescribed
burn used for
nonnative
weed control
Draft Comprehensive Conservation Plan and Environmental Assessment 47
Chapter 5 - Refuge Vision, Goals, and Objectives
The Refuge preserves a remnant of riverine dune ecosystem with a unique assem-blage
of plants and animals. This unique ecosystem supports a northern extension
of species with Mojave Desert rather than coastal affinities. The importance of the
Refuge as a northern California laboratory of desert ecology was unparalleled before
travel to the deserts of southern California became as accessible as it is today.
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 popula-tions
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 appreciation for the unique ecosystem of the
Refuge and an understanding of endangered species protection and the role of the
National Wildlife Refuge System in recovering endangered species.
Management Philosophy
This is a small refuge with little ability to tolerate catastrophic events -- a catastrophic
event at the Refuge could result in the extirpation of one or more species. Because
so much of this ecosystem has been destroyed, it is unlikely that enough habitat
could be protected or duplicated to sustain the endangered species without active
management. Therefore, for the life of this CCP, the Service will concentrate on
adaptive management, performing a series of small management studies that are
believed to benefit the native species. By monitoring the response of the Refuge
resources to these management actions, the Refuge will acquire more data and
more tools with which to manage the Refuge. Objectives may be revised based on
analysis of the data.
Goals
This section presents long-term guidance for the Refuge in the form of goals, objec-tives,
and strategies.
The Service’s planning policy defines a goal as a:
Descriptive, open-ended, and often broad statement of desired future conditions that
conveys a purpose but does not define measurable units.
Refuge goals are qualitative statements that support the Refuge purpose and the
Refuge System mission by providing a vision of how the Refuge should operate and
what the Refuge should be. Goals translate the Refuge purposes into management
direction. Each goal is supported by measurable, achievable objectives which are
the efforts or action items required to achieve the goals. Refuge objectives provide
measurable bench marks that indicate progress towards achieving the Refuge
purpose and goals. Objectives are intended to be accomplished within 15 years,
however, actual implementation may vary depending on staff and funding levels.
Chapter 5 - Refuge Vision, Goals, and Objectives
48 Antioch Dunes National Wildlife Refuge
Strategies are specific actions or projects that will lead to the accomplishment of
management objectives.
Consistent with the legislative framework, described in Chapter 2, that guides the
CCP process, three goals were identified to help guide Refuge planning, develop-ment,
and management.
Goal 1: To protect, enhance, and maintain habitat for threatened and endangered
species, emphasizing species known to inhabit the Refuge, including the Lange’s
metalmark butterfly, Contra Costa wallflower, and Antioch Dunes evening primrose.
Goal 2: To protect, restore, and manage the Antioch Dunes ecosystem for a diversity
of native plant and animal species.
Goal 3: To establish interpretive and educational programs for the public to foster an
appreciation of the natural habitats and endangered species supported by the native
riverine dune habitat of the Refuge.
Endangered Species
Goal 1: To protect, enhance, and maintain habitat for threatened and endangered
species, emphasizing the Lange’s metalmark butterfly, Contra Costa wallflower, and
Antioch Dunes evening primrose (Service 1984).
The Refuge was established to protect three endangered species that are not found
anywhere else in the world. Refuge management options must be weighed carefully
to create a management program that best suits the needs of the endangered
species. Self-sustaining populations are the ultimate goal of Refuge management.
Objective 1.1: Endangered plants on the Refuge and the host plant for the Lange’s
will be self-sustaining and propagate naturally from seed within 15 years.
Narrative: Outplanting has been used on the Refuge for many years as an important
management technique to prevent the possible extinction of endangered species.
No more than 5 percent of the seeds are collected from any individual plant. The
long-term objective for the Refuge is to take habitat management actions so that
outplantings can be reduced and the species can be self-sustaining. However,
outplanting would remain a tool to use against critical population declines.
Strategies:
1.1.1 Propagate and plant the primrose and wallflower on the Refuge when
necessary to prevent species extinction until their populations are self-sustaining.
Outplant buckwheat as needed, for example, in response to wildfire.
1.1.2 Hand-weed a 1½ foot radius around each outplanted primrose at least once
in its lifespan. Greene (1995) found hand-weeding to be very effective at increasing
primrose germination rates. Raking could also be beneficial.
1.1.3 Continue to promote research to determine the best means to optimize seed
production, viability, germination, seedling survival, and reproduction for the
primrose and wallflower.
Chapter 5 - Refuge Vision, Goals, and Objectives
Draft Comprehensive Conservation Plan and Environmental Assessment 49
1.1.4 Encourage genetic diversity by outplanting primrose grown from the seed of
plants at the Brannan Island SRA or the Regional Parks Botanic Garden at Tilden
Regional Park.
Objective 1.2: Determine the environmental parameters that promote natural
regeneration for the primrose, wallflower, and buckwheat.
Narrative: Although much research of these three plant species has been
completed, questions remain unanswered. Due to the fragmented nature of the
dune ecosystem, the small population sizes, and the limited range of the species,
intensive, directed research is needed to assess the effects of management actions
and to assure that the population size of endangered species do not drop below
critical levels. Research shall be directed toward answering management questions.
Although lack of pollinators is not the primary limiting factor affecting primrose and
wallflower population sizes, Pavlik et al. (1988) did find evidence that it may
contribute to lower seed production levels for these plants.
Since extensive demographic research has already been undertaken, demographic
studies to help determine factors that affect the plants’ seed production, viability,
germination, seedling survival, vigor, and reproductive success are a lower priority,
and should be undertaken if focused on specific management needs.
Strategies:
1.2.1 Encourage additional research to clarify the mechanisms by which
competition, water availability, lack of pollinators and other factors limit seedling
establishment.
1.2.2 Collect further data to help the Refuge predict how the primrose, wallflower,
and buckwheat would be affected by Refuge management practices (such as
prescribed burn, herbicide use, disturbance, and public use) and changing
conditions.
1.2.3 Encourage researchers to survey adjacent lands with natural vegetation and
remnant geomorphology similar to the Refuge as sources of native pollinators and to
identify whether activities on adjacent lands (such as pesticide use) affect native
pollinators.
1.2.4 Establish a permanent monitoring program with consistent units of area and
standardized methodologies and protocols. Permanently mark the areas in the field
and record using a global positioning system unit.
1.2.5 Develop a plan to identify and prioritize topics for research.
Objective 1.3: Decrease the amount of invasive nonnative vegetation canopy cover
to less than 50 percent overall in the next 10 years. Some areas would be
intensively managed and have less than 50 percent canopy cover with invasive
nonnative vegetation. Other areas w