Lake Woodruff National Wildlife Refuge Comprehensive Conservation Plan

              Lake Woodruff National Wildlife Refuge
Comprehensive Conservation Plan
U.S. Department of the Interior
Fish and Wildlife Service
Southeast Region
October 2008
Lake Woodruff National Wildlife Refuge
LAKE WOODRUFF NATIONAL WILDLIFE REFUGE
COMPREHENSIVE CONSERVATION PLAN
U.S. Department of the Interior
Fish and Wildlife Service
Southeast Region
Atlanta, Georgia
October 2008
Table of Contents i
TABLE OF CONTENTS
COMPREHENSIVE CONSERVATION PLAN
I. BACKGROUND ................................................................................................................................ 1
Introduction .................................................................................................................................. 1
Purpose and Need for the Plan .................................................................................................... 1
Fish and Wildlife Service .............................................................................................................. 3
National Wildlife Refuge System .................................................................................................. 3
Legal and Policy Context .............................................................................................................. 5
Legal Mandates, Administrative and Policy Guidelines,
and Other Special Considerations ...................................................................................... 5
Biological Integrity, Diversity, and Environmental Health Policy ......................................... 6
National and International Conservation Plans and Initiatives ..................................................... 6
North American Bird Conservation Initiative ....................................................................... 6
North American Waterfowl Management Plan .................................................................... 6
Partners-in-Flight Bird Conservation Plan ........................................................................... 7
U.S. Shorebird Conservation Plan ...................................................................................... 7
North American Waterbird Conservation Plan .................................................................... 7
Relationship to State Wildlife Agency ........................................................................................... 7
II. REFUGE OVERVIEW ........................................................................................................................ 9
Introduction .................................................................................................................................. 9
Refuge History and Purposes ....................................................................................................... 9
Special Designations .................................................................................................................. 11
Research Natural Area ...................................................................................................... 11
Wilderness Area ................................................................................................................ 13
American Heritage River ................................................................................................... 13
Ecosystem Context ..................................................................................................................... 13
Regional Conservation Plans and Initiatives .............................................................................. 16
Ecological Threats and Problems ............................................................................................... 18
Physical Resources .................................................................................................................... 18
Climate .............................................................................................................................. 19
Geology and Topography .................................................................................................. 20
Biological Resources .................................................................................................................. 24
Habitat ............................................................................................................................... 24
Wildlife ............................................................................................................................... 30
Cultural Resources ..................................................................................................................... 41
Socioeconomic Environment ...................................................................................................... 42
Demographics ................................................................................................................... 42
Refuge Administration and Management ................................................................................... 44
Resource Protection .......................................................................................................... 44
Visitor Services ................................................................................................................. 45
Personnel, Operations, and Maintenance ......................................................................... 50
III. PLAN DEVELOPMENT .................................................................................................................. 53
Overview .................................................................................................................................... 53
Public Involvement and Planning Process ................................................................................. 53
ii Lake Woodruff National Wildlife Refuge
Scoping of Issues and Concerns ................................................................................................ 54
Issues ........................................................................................................................................ 54
Wildlife and Habitat Management ..................................................................................... 54
Resource Protection ......................................................................................................... 57
Visitor Services ................................................................................................................. 57
Refuge Administration ...................................................................................................... 58
IV. MANAGEMENT DIRECTION ........................................................................................................ 59
Introduction ............................................................................................................................... 59
Vision ........................................................................................................................................ 59
Goals, Objectives, and Strategies .............................................................................................. 59
Wildlife and Habitat Management ..................................................................................... 60
Resource Protection ......................................................................................................... 95
Visitor Services ............................................................................................................... 100
Refuge Administration .................................................................................................... 109
V. PLAN IMPLEMENTATION ........................................................................................................... 113
Introduction .............................................................................................................................. 113
Proposed Projects .................................................................................................................... 113
Wildlife and Habitat Management ................................................................................... 113
Resource Protection ....................................................................................................... 116
Visitor Services ............................................................................................................... 117
Funding and Personnel ............................................................................................................ 118
Partnership/Volunteers Opportunities ...................................................................................... 121
Step-down Management Plans ................................................................................................ 121
Monitoring and Adaptive Management ..................................................................................... 122
Plan Review and Revision........................................................................................................ 122
APPENDICES
APPENDIX A. GLOSSARY AND ABBREVIATIONS ........................................................................ 123
Glossary .................................................................................................................................. 123
Abbreviations ........................................................................................................................... 131
APPENDIX B. REFERENCES AND LITERATURE CITATIONS ..................................................... 133
APPENDIX C. RELEVANT LEGAL MANDATES AND EXECUTIVE ORDERS ............................... 139
APPENDIX D. PUBLIC INVOLVEMENT .......................................................................................... 153
Summary of Public Scoping Comments ................................................................................... 153
Draft Plan Comments and Service Response .......................................................................... 153
Summary of Concerns and the Service’s Responses ..................................................... 154
APPENDIX E. APPROPRIATE USE DETERMINATIONS ............................................................... 169
APPENDIX F. COMPATIBILITY DETERMINATIONS ...................................................................... 181
APPENDIX G. INTRA-SERVICE SECTION 7 BIOLOGICAL EVALUATION ................................... 207
Table of Contents iii
APPENDIX H. WILDERNESS REVIEW ........................................................................................... 213
APPENDIX I. REFUGE BIOTA ......................................................................................................... 215
APPENDIX J. BUDGET REQUESTS ............................................................................................... 217
APPENDIX K. LIST OF PREPARERS .............................................................................................. 219
APPENDIX L. CONSULTATION AND COORDINATION ................................................................. 221
Introduction ............................................................................................................................... 221
CCP Core Planning Team ........................................................................................................ 221
Wildlife and Habitat Management Review Team ...................................................................... 221
Visitor Services Review Team .................................................................................................. 223
Wilderness Review Team ......................................................................................................... 223
Intergovernmental Coordination Planning Team ...................................................................... 223
APPENDIX M. FINDING OF NO SIGNIFICANT IMPACTS .............................................................. 225
Introduction ............................................................................................................................... 225
Alternatives ............................................................................................................................... 225
Alternative A. Current Management (No Action Alternative) .......................................... 225
Alternative B. Migratory Birds ......................................................................................... 227
Alternative C. Rare, Threatened, and Endangered Species .......................................... 229
Alternative D. Wildlife and Habitat Diversity (Preferred Alternative) .............................. 232
Selection Rationale ................................................................................................................... 236
Environmental Effects ............................................................................................................... 236
Potential Adverse Effects and Mitigation Measures ................................................................. 236
Wildlife Disturbance ........................................................................................................ 236
User Group Conflicts ....................................................................................................... 237
Effects on Adjacent Landowners ..................................................................................... 237
Land Ownership and Site Development .......................................................................... 237
Coordination ............................................................................................................................. 238
Findings ................................................................................................................................... 238
Supporting References ............................................................................................................. 239
Document Availability ............................................................................................................... 239
iv Lake Woodruff National Wildlife Refuge
LIST OF FIGURES
FIGURE 1. LAKE WOODRUFF NWR VICINITY MAP ......................................................................... 2
FIGURE 2. FARM SERVICE AGENCY CONSERVATION EASEMENT PROPERTIES
MANAGED BY LAKE WOODRUFF NWR ........................................................................ 12
FIGURE 3. LAKE WOODRUFF NWR RESEARCH NATURAL AREA AND WILDERNESS
AREA MAP ....................................................................................................................... 14
FIGURE 4. NORTH FLORIDA ECOREGIONS ................................................................................... 17
FIGURE 5. AREA CONSERVATION LANDS ...................................................................................... 17
FIGURE 6. LAKE WOODRUFF NWR IMPOUNDMENT MANAGEMENT UNITS .............................. 26
FIGURE 7. LAKE WOODRUFF NWR FIRE MANAGEMENT UNITS ................................................. 27
FIGURE 8. LAKE WOODRUFF NWR VEGETATION TYPES ............................................................ 28
FIGURE 9: LAKE WOODRUFF NWR LAND STATUS MAP ............................................................... 46
FIGURE 10. LAKE WOODRUFF NWR PUBLIC USE AREAS ............................................................ 48
FIGURE 11: LAKE WOODRUFF NWR HUNT AREAS ....................................................................... 49
FIGURE 12: LAKE WOODRUFF NWR CURRENT ORGANIZATIONAL CHART............................... 51
FIGURE 13: LAKE WOODRUFF NWR PROPOSED ORGANIZATIONAL CHART .......................... 119
Table of Contents v
LIST OF TABLES
TABLE 1: HABITAT TYPES AND THEIR ASSOCIATED ACREAGES (BASED ON GIS
CALCULATIONS FROM 2004 SJRWMD DOQQ’S) ........................................................... 25
TABLE 2: LAKE WOODRUFF NWR LISTED SPECIES...................................................................... 34
TABLE 3: LAKE WOODRUFF NWR NON-NATIVE PLANTS AND ANIMALS .................................... 40
TABLE 4: POPULATIONS OF THE REFUGE’S HOME COUNTIES AND NEARBY COUNTIES ...... 43
TABLE 5: POPULATIONS OF CITIES OF VOLUSIA COUNTY, FLORIDA ........................................ 43
TABLE 6: SUMMARY OF PROJECTS (STAFF POSITIONS INDICATE PARTIAL FTE'S - SEE
FIGURE 13 FOR PROPOSED STAFFING LEVEL) .......................................................... 120
TABLE 7: LAKE WOODRUFF NWR STEP-DOWN MANAGEMENT PLANS ................................... 121
vi Lake Woodruff National Wildlife Refuge
Comprehensive Conservation Plan 1
COMPREHENSIVE CONSERVATION PLAN
I. BACKGROUND
INTRODUCTION
Located along Florida’s St. Johns River about 25 miles west of the city of Daytona Beach in Volusia
and Lake Counties, Lake Woodruff National Wildlife Refuge (NWR) was established for migratory
waterfowl and wading birds (Figure 1). The refuge is part of a 70-mile-long wildlife corridor of
ecologically sensitive lands along the St. Johns River, stretching from the Wekiva River to Lake
George. The 21,574-acre refuge supports a diversity of wildlife and plant species, including a variety
of waterfowl, shorebirds, and neotropical migratory birds, as well as numerous Federal- or State-listed
species through a mix of freshwater marshes, rivers, impounded wetlands, and upland shrublands
and forests. The refuge includes two major water bodies, which are part of the St. Johns River
system: Lake Woodruff and Lake Dexter. The refuge supports at least two pairs of bald eagles,
foraging habitat for wood storks, the second largest pre-migration roosting colony in the southeastern
United States for swallow-tailed kites with over 900 individuals, and manatee habitat. It is an
overwinter and stopover site for a variety of waterfowl, shorebirds, and neotropical migratory birds.
The refuge includes over 1,000 acres of wilderness. Furthermore, the refuge protects historical and
archaeological sites. A growing human population, along with ongoing development and other
human activities, currently threaten the largest river in Florida and the refuge. The refuge is part of a
larger Refuge Complex in central and southeast Florida, including Merritt Island and St. Johns NWRs
in Titusville; Archie Carr NWR between Melbourne and Wabasso Beaches; Pelican Island NWR near
Sebastian; and Lake Wales Ridge NWR in Highlands and Polk Counties, near Sebring.
This Comprehensive Conservation Plan (CCP) for Lake Woodruff NWR was prepared to guide
management actions and direction for the refuge. Fish and wildlife conservation will receive first
priority in refuge management; wildlife-dependent recreation will be allowed and encouraged as long
as it is appropriate and compatible with, and does not detract from, the mission of the refuge or the
purposes for which it was established.
The Service developed a range of alternatives that best met the goals and objectives of the refuge and that
could be implemented within the 15-year planning period. These alternatives are presented and analyzed in
the environmental assessment (EA). The Draft CCP/EA describes the Fish and Wildlife Service’s proposed
plan, as well as other alternatives considered and their effects on the environment. The Draft CCP/EA was
made available to State and Federal government agencies, conservation partners, and the general public
for review and comment from April 23 through June 23, 2008. Comments from each entity were considered
in the development of the Final CCP.
PURPOSE AND NEED FOR THE PLAN
The purpose of the CCP is to implement a management action that best achieves the refuge purposes, vision,
and goals; contributes to National Wildlife Refuge System (Refuge System) mission; addresses key problems,
issues, and relevant mandates; and is consistent with sound principles of fish and wildlife management.
Specifically, the plan is needed to:
􀁹􇤠 Provide a clear statement of refuge management direction;
􀁹􇤠 Provide refuge neighbors, visitors, and government officials with an understanding of Service
management actions on and around the refuge;
2 Lake Woodruff National Wildlife Refuge
Figure 1. Lake Woodruff NWR vicinity map
Comprehensive Conservation Plan 3
􀁹􇤠 Ensure that Service management actions, including land protection and recreation/education
programs, are consistent with the mandates of the National Wildlife Refuge System; and
􀁹􇤠 Provide a basis for the development of budget requests for operations, maintenance, and
capital improvement needs.
FISH AND WILDLIFE SERVICE
The Fish and Wildlife Service (Service) traces its roots to 1871 and the establishment of the
Commission of Fisheries involved with research and fish culture. The once independent commission
was renamed the Bureau of Fisheries and placed in the Department of Commerce and Labor in 1903.
The Service also traces its roots to 1886 and the establishment of a Division of Economic Ornithology
and Mammalogy in the Department of Agriculture. Research on the relationship of birds and animals
to agriculture shifted to delineation of the range of plants and animals so the name was changed to
the Division of the Biological Survey in 1896.
The Department of Commerce, Bureau of Fisheries, was combined with the Department of
Agriculture, Bureau of Biological Survey, on June 30, 1940, and transferred to the Department of the
Interior as the Fish and Wildlife Service. The name was changed to the Bureau of Sport Fisheries
and Wildlife in 1956, and finally to the U.S. Fish and Wildlife Service in 1974.
The Service is responsible for conserving, enhancing, and protecting fish and wildlife and their
habitats for the continuing benefit of people through Federal programs relating to wild birds,
endangered species, certain marine mammals, inland sport fisheries, and specific fishery and wildlife
research activities (142 DM 1.1).
The Service is the principal Federal agency responsible for conserving, protecting and enhancing
fish, wildlife and plants and their habitats for the continuing benefit of the American people. The
Service manages the 97-million-acre National Wildlife Refuge System, which encompasses 545
national wildlife refuges, thousands of small wetlands, and other special management areas. It also
operates 69 national fish hatcheries, 63 fish and wildlife management offices and 81 ecological
services field stations. The Service enforces Federal wildlife laws; administers the Endangered
Species Act; manages migratory bird populations; restores nationally significant fisheries; conserves
and restores wildlife habitat, such as wetlands; and helps foreign governments with their conservation
efforts. It also oversees the Federal Aid program, which distributes hundreds of millions of dollars in
excise taxes on fishing and hunting equipment to State fish and wildlife agencies.
NATIONAL WILDLIFE REFUGE SYSTEM
The mission of the National Wildlife Refuge System, as defined by the National Wildlife Refuge
System Improvement Act of 1997 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 Americans”.
The National Wildlife Refuge System Improvement Act of 1997 established, for the first time, a clear
legislative mission of wildlife conservation for the National Wildlife Refuge System (Refuge System).
Actions were initiated in 1997 to comply with the direction of this new legislation, including an effort to
complete CCPs for all refuges. These CCPs, which are completed with full public involvement, help
guide the future management of refuges by establishing natural resources and recreation/education
4 Lake Woodruff National Wildlife Refuge
programs. Consistent with this Act, approved CCPs will serve as the guidelines for refuge
management for the next 15 years. The Act states that each refuge shall be managed to:
􀁹􇤠 Fulfill the mission of the National Wildlife Refuge System;
􀁹􇤠 Fulfill the individual purposes of each refuge;
􀁹􇤠 Consider the needs of wildlife first;
􀁹􇤠 Fulfill requirements of comprehensive conservation plans that are prepared for each unit of
the Refuge System;
􀁹􇤠 Maintain the biological integrity, diversity, and environmental health of the Refuge System;
􀁹􇤠 Recognize that wildlife-dependent recreation activities including hunting, fishing, wildlife
observation, wildlife photography, and environmental education and interpretation are
legitimate and priority public uses; and
􀁹􇤠 Allow refuge managers the authority to determine compatible public uses.
The following are just a few examples of the national network of conservation lands. Pelican Island
National Wildlife Refuge, the first refuge, was established in 1903, for the protection of colonial
nesting birds in Florida, such as the snowy egret and the brown pelican. Western refuges were
established for American bison (1906), elk (1912), prong-horned antelope (1931), and desert bighorn
sheep (1936), after over-hunting, competition with cattle, and natural disasters decimated once-abundant
herds. The drought conditions of the 1930s’ Dust Bowl severely depleted breeding
populations of ducks and geese. Refuges established during the Depression focused on waterfowl
production areas (i.e., protection of prairie wetlands in America's heartland). The emphasis on
waterfowl continues today, but also includes protection of wintering habitat in response to a dramatic
loss of bottomland hardwoods. By 1973, the Service began to focus on establishing refuges for
endangered species.
Approximately 37 million people visited national wildlife refuges in 2004, most to observe wildlife in
their natural habitats, creating almost 24,000 private sector jobs and producing about $454 million in
employment income (Caudill and Henderson 2005). Further, recreational spending on refuges
generated nearly $151 million in tax revenue at the local, county, State, and Federal levels (Caudill
and Henderson 2005). As the number of visitors grows, local communities realize important
economic benefits. In 2001, 82 million people, 16 years and older, fished, hunted, or observed
wildlife, generating $108 billion. In a study completed in 2002 on 15 refuges, visitation had grown 36
percent in 7 years. At the same time, the number of jobs generated in surrounding communities grew
to 120 per refuge, up from 87 jobs in 1995, pouring more than $2.2 million into local economies. The
15 refuges in the study were Chincoteague (Virginia); National Elk (Wyoming); Crab Orchard (Illinois);
Eufaula (Alabama); Charles M. Russell (Montana); Umatilla (Oregon); Quivira (Kansas);
Mattamuskeet (North Carolina); Upper Souris (North Dakota); San Francisco Bay (California); Laguna
Atacosa (Texas); Horicon (Wisconsin); Las Vegas (Nevada); Tule Lake (California); and Tensas River
(Louisiana)—the same refuges identified for the 1995 study. Other findings also validate the findings
that communities near refuges benefit economically. Expenditures on food, lodging, and
transportation grew to $6.8 million per refuge, up 31 percent from $5.2 million in 1995. For each
Federal dollar spent on the Refuge System, surrounding communities benefited with $4.43 in
recreation expenditures and $1.42 in job-related income (Caudill and Laughland, unpubl. data).
Volunteers and friends groups continue to be a major contributor to the success of the Refuge
System. In 2005, volunteers contributed more than 1.4 million hours on refuges nationwide, a
service valued at more than $25 million and representing a full-time employee equivalent of
over 700 (U.S. Fish and Wildlife Service 2006). And, in 2005, nine new friends groups were
Comprehensive Conservation Plan 5
formed to support refuge management programs and operations, bringing the Refuge System’s
total to over 200 (U.S. Fish and Wildlife Service 2006).
The wildlife and habitat vision for national wildlife refuges stresses that wildlife comes first; that
ecosystems, biodiversity, and wilderness are vital concepts in refuge management; that refuges must
be healthy and growth must be strategic; and that the Refuge System serves as a model for habitat
management with broad participation from others.
The National Wildlife Refuge System Improvement Act of 1997 stipulates that CCPs be prepared in
consultation with adjoining Federal, State, and private landowners and that the Service develop and
implement a process to ensure an opportunity for active public involvement in the preparation and
revision (every 15 years) of the CCPs.
All lands of the Refuge System will be managed in accordance with an approved CCP that will guide
management decisions and set forth strategies for achieving refuge unit purposes. The CCP will be
consistent with sound resource management principles, practices, and legal mandates including Service
compatibility standards, and other Service policies, guidelines, and planning documents (602 FW 1.1).
LEGAL AND POLICY CONTEXT
LEGAL MANDATES, ADMINISTRATIVE AND POLICY GUIDELINES, AND OTHER SPECIAL
CONSIDERATIONS
Administration of national wildlife refuges is guided by the mission and goals of the National Wildlife
Refuge System, congressional legislation, Presidential executive orders, and international treaties.
Policies for management options of refuges are further refined by administrative guidelines
established by the Secretary of the Interior and by policy guidelines established by the Director of the
Fish and Wildlife Service. Select legal summaries of treaties and laws relevant to administration of
the Refuge System and management of the Lake Woodruff NWR are provided in Appendix C.
Treaties, laws, administrative guidelines, and policy guidelines assist the refuge manager in making
decisions pertaining to soil, water, air, flora, fauna, and other natural resources; historical and cultural
resources; research; and recreation on refuge lands, and provide a framework for cooperation
between Lake Woodruff NWR and other partners, such as the Florida Fish and Wildlife Conservation
Commission (FWC), St. Johns River Water Management District (SJRWMD), National Park Service
(NPS), United States Department of Agriculture Forest Service (USDA Forest Service), U.S. Army
Corps of Engineers (Corps), Florida Department of Environmental Protection (FDEP), De Leon
Springs State Park, organizations, private landowners, businesses, and the public.
Lands within the Refuge System are closed to public use unless specifically and legally opened. No
refuge use may be allowed unless it is determined to be appropriate and compatible. A compatible
use is a use that, in the sound professional judgment of the refuge manager, will not materially
interfere with or detract from the fulfillment of the mission of the Refuge System or the purposes of
the refuge. All programs and uses must be evaluated based on mandates set forth in the
Improvement Act. Those mandates are to:
􀁹􇤠 Contribute to ecosystem goals, as well as to refuge purpose(s) and goals;
􀁹􇤠 Conserve, manage, and restore fish, wildlife, and plant resources and their habitats;
􀁹􇤠 Monitor the trends of fish, wildlife, and plants;
6 Lake Woodruff National Wildlife Refuge
􀁹􇤠 Manage and ensure appropriate visitor uses as those uses benefit the conservation of fish
and wildlife resources and contribute to the enjoyment of the public; and
􀁹􇤠 Ensure that visitor activities are compatible with refuge purposes.
The Improvement Act further identifies six priority wildlife-dependent recreational uses: hunting,
fishing, wildlife observation, wildlife photography, environmental education and interpretation. As
priority public uses of the Refuge System, they receive priority consideration over other public uses in
planning and management.
BIOLOGICAL INTEGRITY, DIVERSITY, AND ENVIRONMENTAL HEALTH POLICY
The Improvement Act directs the Service to ensure that the biological integrity, diversity, and
environmental health of the Refuge System are maintained for the benefit of present and future
generations of Americans. The policy is an additional directive for refuge managers to follow while
achieving refuge purpose(s) and the Refuge System mission. It provides for the consideration and
protection of the broad spectrum of fish, wildlife, and habitat resources found on refuges and
associated ecosystems. When evaluating the appropriate management direction for refuges, refuge
managers will use sound professional judgment to determine their refuges’ contributions to biological
integrity, diversity, and environmental health at multiple landscape scales. Sound professional
judgment incorporates field experience with knowledge of refuge resources, the refuge’s role within
an ecosystem, applicable laws, and best available science, including consultation with others both
inside and outside the Service.
NATIONAL AND INTERNATIONAL CONSERVATION PLANS AND INITIATIVES
Multiple partnerships have been developed among government and private entities to address the
environmental problems affecting regions. There is a large amount of conservation and protection
information that defines the role of the refuge at the local, national, international, and ecosystem
levels. Conservation initiatives include broad-scale planning and cooperation between affected
parties to address declining trends of natural, physical, social, and economic environments. The
conservation guidance described below, along with issues, problems and trends, was reviewed and
integrated where appropriate into this CCP.
This CCP supports, among others, the Partners-in-Flight Plan, the North American Waterfowl
Management Plan, the Western Hemisphere Shorebird Reserve Network, and the National Wetlands
Priority Conservation Plan.
NORTH AMERICAN BIRD CONSERVATION INITIATIVE
Started in 1999, the North American Bird Conservation Initiative (NABCI) is a coalition of government
agencies, private organizations, academic institutions, and private industry leaders in the United
States, Canada, and Mexico, working to ensure the long-term health of North America's native bird
populations by fostering an integrated approach to bird conservation to benefit all birds in all habitats.
The four international and national bird initiatives include the North American Waterfowl Management
Plan, Partners-in-Flight, Waterbird Conservation for the Americas, and the U.S. Shorebird
Conservation Plan.
NORTH AMERICAN WATERFOWL MANAGEMENT PLAN
The North American Waterfowl Management Plan (NAWMP) is an international action plan to
conserve migratory birds throughout the continent (NAWMP 2004). NAWMP’s goal is to return
Comprehensive Conservation Plan 7
waterfowl populations to their 1970s’ levels by conserving wetland and upland habitat. Canada and
the United States signed the NAWMP in 1986, in reaction to critically low numbers of waterfowl.
Mexico joined in 1994, making it a truly continental effort. The NAWMP is a partnership of Federal,
Provincial/State and municipal governments, non-governmental organizations, private companies,
and many individuals, all working towards achieving better wetland habitat for the benefit of migratory
birds, other wetland-associated species, and people. NAWMP projects are international in scope, but
implemented at regional levels. These projects contribute to the protection of habitat and wildlife
species across the North American landscape. Lake Woodruff NWR plays a positive role in NAWMP
through wetlands protection and multi-species habitat management.
PARTNERS-IN-FLIGHT BIRD CONSERVATION PLAN
Managed as part of the Partners-in-Flight Plan (PIF), the North Florida Ecosystem physiographic area
represents a scientifically based land bird conservation planning effort that ensures long-term
maintenance of healthy populations of native land birds, primarily non-game land birds (Rich et al.,
2004). Non-game land birds have been vastly under-represented in conservation efforts, and many
are exhibiting significant declines. PIF is voluntary and non-regulatory, and focuses on relatively
common species in areas where conservation actions can be most effective, rather than the frequent
local emphasis on rare and peripheral populations. Lake Woodruff NWR contributes to several PIF
landbird conservation objectives, including the protection of migratory and breeding habitat and multi-species
habitat management.
U.S. SHOREBIRD CONSERVATION PLAN
The U.S. Shorebird Conservation Plan (SCP) is a partnership effort throughout the United States to
ensure that stable and self-sustaining populations of shorebird species are restored and protected
(Brown et al., 2001). The SCP was developed by a wide range of agencies, organizations, and
shorebird experts for separate regions of the country, and identifies conservation goals, critical
habitat conservation needs, key research needs, and proposed education and outreach programs to
increase awareness of shorebirds and the threats they face. Lake Woodruff NWR plays a role in the
SCP through the protection and management of shorebird habitat and monitoring programs.
NORTH AMERICAN WATERBIRD CONSERVATION PLAN
The North American Waterbird Conservation Plan (NAWCP) provides a framework for the
conservation and management of 210 species of waterbirds in 29 nations (Kushlan et al., 2002).
Threats to waterbird populations include destruction of inland and coastal wetlands, introduced
predators and invasive species, pollutants, mortality from fisheries and industries, disturbance, and
conflicts arising from abundant species. Particularly important habitats of the Southeast Region
include pelagic areas, marshes, forested wetlands, and barrier and sea island complexes. Fifteen
species of waterbirds are federally listed, including breeding populations of wood storks, Mississippi
sandhill cranes, whooping cranes, interior least terns, and Gulf Coast populations of brown pelicans.
A key objective of the NAWCP is the standardization of data collection efforts to better recommend
effective conservation measures. Lake Woodruff NWR contributes toward several of the NAWCP
goals by helping maintain waterbird diversity and protecting and managing waterbird habitat.
RELATIONSHIP TO STATE WILDLIFE AGENCY
A provision of the Improvement Act, and subsequent agency policy, is that the Service shall ensure
timely and effective cooperation and collaboration with other State fish and game agencies and Tribal
governments during the course of acquiring and managing refuges. State wildlife management areas
8 Lake Woodruff National Wildlife Refuge
and national wildlife refuges provide the foundation for the protection of species, and contribute to the
overall health and sustainment of fish and wildlife species in the State of Florida.
Lake Woodruff NWR’s State agency partners include: Florida Fish and Wildlife Conservation
Commission (FWC), Florida Department of Environmental Protection (FDEP), Florida Division of
Forestry (FDOF), and St. Johns River Water Management District (SJRWMD). Management of State
fish and wildlife is administered by the FWC and the FDEP. These State agencies are charged with
enforcement responsibilities relating to migratory birds, trust species, and fisheries, as well as with
management of natural resources of the State. Both FWC and FDEP manage the State’s lands and
waters. The FWC manages 4.3 million acres of public lands and 220,000 acres of private lands for
recreation and conservation purposes. The FDEP manages 150 State parks, covering nearly
600,000 acres and 57 coastal and aquatic managed areas, totaling over 5 million acres of submerged
lands and coastal uplands. The SJRWMD has some form of interest in approximately 640,000 acres
of property through ownership, management, or conservation easement rights. And further
acquisitions are planned by the SJRWMD.
Various State agencies have participated in a series of refuge projects, including the planning
process to develop a 15-year management plan for the refuge. An integral part of the CCP process
is integrating common mission objectives, where appropriate. The State’s participation and
contribution throughout this planning process will provide for ongoing opportunities and open dialogue
to improve the ecological sustainment of fish and wildlife in the State of Florida. An essential part of
comprehensive conservation planning is integrating common mission objectives where appropriate.
Comprehensive Conservation Plan 9
II. REFUGE OVERVIEW
INTRODUCTION
Lake Woodruff NWR consists of ~21,574 acres in central Florida along the St. Johns River, Florida’s
largest river (Figure 1). The St. Johns River is a series of interconnected lakes that stretches 310 miles
from its southern formation in Indian River County’s swamps north to Jacksonville in Duval County near
the Florida-Georgia border. The geographical position of the refuge, straddling the zone of overlap
between the temperate and subtropical biotic provinces, contributes to the vast species richness of the
area. The refuge is uniquely situated to support a wide variety of resident and migratory species. The
refuge derives its name from Lake Woodruff, a 2,200-acre waterbody formed during the Pleistocene
[100,000 years before present (BP)] when the St. Johns River basin was a large coastal lagoon
complex. The eastern boundary of the refuge is part of an ancient dune system known as the Atlantic
Coastal Ridge (Schnable and Goodell 1968) which formed when sea levels fell sharply during
glaciation. The resulting differences in elevation present on the refuge, from prehistoric dunes to
shallow lakes, have created a variety of habitats, including freshwater marshes, hardwood swamps,
and a variety of upland habitats. These diverse refuge habitats support numerous plant species and
are utilized by many fish and wildlife species, including seven regularly occurring Federal listed
threatened and endangered species, as well as numerous State protected species. Although the
refuge is important to a variety of species, it is especially important to swallow-tailed kites. The refuge
supports the second largest pre-migration roost of swallow-tailed kites in the United States.
Primary habitat management activities on the refuge involve applying prescribed fire, using
mechanical treatments in upland scrub, employing chemical control of exotic plants, and
managing water levels in impounded wetlands. Low-intensity prescribed burning activities help to
enhance and maintain vegetative communities that are dependent upon or positively influenced
by fire, for the benefit of wildlife; to promote nutrient cycling; and to reduce an unnatural buildup
of fuels that could otherwise create hazardous, high-intensity wildfires. The refuge’s three
impounded wetlands are seasonally manipulated to benefit migratory waterfowl, wading birds,
shorebirds, and other wildlife. Additional upland management activities include the periodic
thinning of pine flatwoods to enhance nesting habitat for bald eagles and gopher tortoises, as well
as the control of exotic, invasive, and nuisance species.
REFUGE HISTORY AND PURPOSES
Lake Woodruff NWR is located near the historic Ponce de Leon Springs State Park, which was
named for the famed Spanish explorer who may have led Spanish forces through this area in 1513 in
his quest for the Fountain of Youth. Development of this area dates back to when the Spaniards
cleared a small area, planted it in sugar cane, and built a mill to process the cane. Prior to Spanish
exploration, this area was occupied by the Timucuan Indians and their predecessors dating back
8,000 years. Numerous Indian mounds and middens are located throughout this area.
In more modern times, cattle were grazed on Jones and Tick Islands for at least 75 years. An orange
grove and farming operations were on Tick Island during the late 1800s. According to local sources,
in 1804, William Williams moved from New Smyrna Beach to settle at Spring Garden, now known as
DeLeon Springs, and was the first to raise corn and cotton. After Florida became a United States
territory in 1821, Major Joseph Woodruff bought out Williams’ 2,020-acre share of Spring Garden in
1823. The lake became known as Lake Woodruff and the refuge was later named accordingly.
10 Lake Woodruff National Wildlife Refuge
In 1952, a private land developer made an abortive attempt to develop about 3,000 acres east of
Lake Woodruff for agriculture. Levees were constructed and two 2,400 gallons per minute (GPM)
pumps were installed to drain the land. This venture was found to be impractical and was
abandoned. The pine timber was removed from Jones Island in 1957-58. Pine, cypress, and oak
timber were removed from Tick and Dexter Islands before the Federal Government bought the land.
Prior to acquisition, timber and shell removal operations occurred on Tick Island. Though not
associated with management of the refuge, these activities continued to be conducted on Tick Island
per previous land-use agreements.
In 1964, the Service began purchasing land for the refuge. The Wilderness Act was established that
same year. Additional land was incorporated into the area presently occupied by the refuge. Lake
Woodruff NWR was established in 1964 as a migratory bird refuge to offset losses of wetland habitat
in central Florida. The refuge contains ~21,574 acres and is comprised of approximately 11,100
acres of freshwater marsh; 7,200 acres of hardwood swamps; 2,400 acres of uplands; and more than
800 acres of lakes, streams, and canals. Lake Woodruff NWR also administers an additional nearly
660 acres of Farm Service Agency (FSA) conservation easements (Figure 2).
Approximately one mile from the main entrance, the refuge’s headquarters office is located in the
town of DeLeon Springs, Florida, which is 25 miles west of Daytona Beach. This headquarters office
also serves as a visitor contact station, with a few displays, information, maps, and a small sales
outlet operated by the Friends of Lake Woodruff National Wildlife Refuge. Lake Woodruff NWR
encircles the State-owned water of Lake Woodruff and the St. Johns River forms much of the western
boundary. The majority lies within Volusia County with only a very minor portion in Lake County. The
Ocala National Forest lies west and the Lake George State Forest and DeLeon Springs State Park
are immediately to the north and northeast of the refuge.
Wildlife diversity is typical of that associated with central Florida wetlands. Lake Woodruff NWR’s bird
list names 234 species, which can be seasonally found in the area. In addition to the numerous
wetland species, several Federal listed species also use the refuge, including: West Indian manatee,
snail kite, wood stork, eastern indigo snake, American alligator, and whooping crane. In the early
years of the refuge, some of the existing marsh was impounded to attract waterfowl and wading birds.
Three impoundments, totaling ~450 acres, now exist at Lake Woodruff NWR and provide loafing and
foraging areas for migratory birds. The impoundments are the most popular areas for public use,
including bird watching, hiking, and fishing.
Recognizing the high migratory bird benefits served by the lands and waters of the refuge, the
Service administratively designated Lake Woodruff NWR in 1963 under the Migratory Bird
Conservation Act, outlining a primary purpose of these lands and waters:
􀁹􇤠 "...for use as an inviolate sanctuary, or for any other management purpose, for migratory
birds." 16 U.S.C. § 715d (Migratory Bird Conservation Act)
In addition, the refuge has several additional purposes, as listed.
􀁹􇤠 “…suitable for (1) incidental fish and wildlife-oriented recreation development, (2) the
protection of natural resources, (3) the conservation of endangered species or threatened
species…” 16 U.S.C. § 460k-1 (Refuge Recreation Act)
􀁹􇤠 “…the Secretary…may accept and use…real…property. Such acceptance may be
accomplished under the terms and conditions of restrictive covenants imposed by donors…”
16 U.S.C. § 460k-2 (Refuge Recreation Act)
Comprehensive Conservation Plan 11
􀁹􇤠 “…wilderness areas…shall be administered for the use and enjoyment of the American people
in such manner as will leave them unimpaired for future use and enjoyment as wilderness,
and so as to provide for the protection of these areas, the preservation of their wilderness
character, and for the gathering and dissemination of information regarding their use and
enjoyment as wilderness…” 16 U.S.C. § 1131 (Wilderness Act)
􀁹􇤠 “…for the development, advancement, management, conservation, and protection of fish and
wildlife resources…” 16 U.S.C. § 742f(a)(4) (Fish and Wildlife Act of 1956)
􀁹􇤠 “…for the benefit of the United States Fish and Wildlife Service, in performing its activities and
services. Such acceptance may be subject to the terms of any restrictive or affirmative
covenant or condition of servitude…” 16 U.S.C. § 742f(b)(1) (Fish and Wildlife Act of 1956)
􀁹􇤠 “…conservation, management, and restoration of the fish, wildlife, and plant resources and
their habitats for the benefit of present and future generations of Americans…” 16 U.S.C. §
668dd(a)(2) (National Wildlife Refuge System Administration Act)
􀁹􇤠 “…to conserve (A) fish or wildlife which are listed as endangered species or threatened
species…or (B) plants…” 16 U.S.C. § 1534 (Endangered Species Act)
SPECIAL DESIGNATIONS
Lake Woodruff NWR holds two special designations: Research Natural Area and Wilderness
Area, totaling about 914 hectares (ha)/2,258.64 acres (which represent about 10.5 percent of the
total refuge area). And the St. Johns River that flows through the refuge is designated as an
American Heritage River.
RESEARCH NATURAL AREA
Research natural areas are part of a national network of reserved areas under various federal
ownerships. Research natural areas are intended to represent the full array of North American
ecosystems with their biological communities, habitats, natural phenomena, and geological and
hydrological formations. Lake Woodruff NWR has 461 ha (1,140 acres) of designated
Research Natural Area along Honey Creek, in the southern part of the refuge (Figure 3). This
area represents native southern cordgrass prairie habitat. Management guidelines are not
dictated for research natural areas, instead natural processes are allowed to predominate
without human intervention. Under certain circumstances, deliberate manipulation may be used
to maintain the unique features for which the research natural area was established. Research
natural areas receive minimal management consisting of sporadic controlled burns of marsh
grasses and occasional law enforcement.
12 Lake Woodruff National Wildlife Refuge
Figure 2. Farm Service Agency conservation easement properties managed by Lake Woodruff
NWR
Comprehensive Conservation Plan 13
WILDERNESS AREA
The Wilderness Act of 1964 established the National Wilderness Preservation System and established
guidelines for management of those areas. In the 1970s proposals were considered for Wilderness on
the refuge, ranging from 1,146 acres to 2,200 acres to 8,606 acres. Ultimately, under Public Law 94-557
(see 16 U.S.C. Chapter 23 §1132), Congress designated an estimated 1,146 acres as Wilderness on the
refuge on October 19, 1976 (which includes Audubon and Bird Islands, Dexter Island, and St. Francis
Island; Figure 3). This original acreage figure was estimated and current estimates total 1,066.41 acres:
the 49.52-acre Audubon Island; the 2.92-acre, 0.15-acre, and 0.05-acre Bird Islands; 707.85-acre Dexter
Island; and the 305.92-acre St. Francis Island. Although addressed in the 1976 designation of
wilderness, the northwest tip of Dexter Island (~59 acres) was private lands in 1976. This small piece of
Dexter Island was added to the Wilderness Area with its acquisition in 1979. Adjacent to the refuge and
to the refuge’s Wilderness Area is the ±7,985-acre Alexander Springs Wilderness Area and nearby is the
±3,120-acre Billies Bay Wilderness Area, both of which were designated in 1983, and which are managed
by the USDA Forest Service as part of Ocala National Forest (Figure 3).
The Wilderness Area is comprised of remote islands that offer limited access to the public. Active
management of these areas is restricted by guidelines contained in the Wilderness Act. Current
management of the Wilderness islands is best described as minimum impact. The areas defined as
Wilderness are islands that are mostly hardwood swamp forest, which require very little human
intervention. Currently, Refuge Complex staff conducts sporadic prescribed burns on the small
burnable sections of Bird, Audubon, and Dexter islands to maintain habitat quality. As needed, the
refuge replaces boundary signs that designate the Wilderness Area. These refuge signs are the only
authorized and maintained human material on the islands. No structures or facilities exist within the
refuge’s Wilderness Area. Other management activities include occasional law enforcement, usually
during hunting seasons. Since the Wilderness Area is comprised of islands, which limits public
access, threats to the Wilderness Area are minimized and include erosion of the smaller islands,
littering, and illegal hunting and poaching activities.
AMERICAN HERITAGE RIVER
The St. Johns River is an important feature of the refuge both in terms of the area it covers, as well as
its influence on low-lying habitats. The St. Johns River was designated by executive order as an
American Heritage River in 1998. The American Heritage Rivers’ initiative has three objectives:
natural resource and environmental protection, economic revitalization, and historic and cultural
preservation. Only 14 rivers in the United States have this designation.
ECOSYSTEM CONTEXT
Comprising one of the 52 ecosystems around the country, the Service’s North Florida Ecosystem includes
portions of southern Georgia and most of northern and central Florida (Figure 4), spanning 33 Florida
counties and 19 Georgia counties. The North Florida Ecosystem includes several important areas with
protective designations, including Ocala National Forest and Okefenokee and Lake Woodruff NWRs.
Thirteen national wildlife refuges and one national fish hatchery are located in the North Florida Ecosystem.
Various other local, State, and Federal conservation areas are also located within the North Florida
Ecosystem. The ecosystem spans temperate and subtropical climates, numerous physiographic districts,
and a wide variety of habitats. These include barrier islands, xeric scrub, pine flatwoods, freshwater
marshes, lakes, streams, springs, mixed hardwood/pine forests, cypress swamps and domes, dry prairies,
maritime forests, hardwood hammocks, estuarine marshes, pine rocklands, sandhill woodlands, coastal
strands, sawgrass prairies, sloughs, and tree islands. The ecosystem serves a variety of native wildlife,
including over 100 federal listed species, as well as interjurisdictional fishes, neotropical migratory birds,
14 Lake Woodruff National Wildlife Refuge
Figure 3. Lake Woodruff NWR research natural area and wilderness area map
Comprehensive Conservation Plan 15
Figure 4. North Florida ecoregions
16 Lake Woodruff National Wildlife Refuge
non-game waterbirds, and waterfowl. The biggest problem facing the ecosystem is habitat loss and
fragmentation caused by development and other human activities. The predominant stresses for the
ecosystem are: population growth, tourism, agriculture, silviculture, mining, water channelization,
urbanization, aquifer depletion, fire suppression, exotic species, non-point source pollution, and point source
pollution (U.S. Fish and Wildlife Service 1996). The actions of the ecosystem team are guided by two
categories: trust resources and management issues. The trust resources include: migratory birds,
anadromous fish, endangered species, and marine mammals. The management issues focus on:
habitat protection and management, habitat restoration, contaminant reduction, regulatory
compliance, law enforcement, and biodiversity maintenance.
To address these threats, management issues, and needs of the trust resources, the ecosystem team
pursues a variety of objectives under five goals:
􀁹􇤠 Protect, conserve, and enhance migratory birds and their habitats in the North Florida
Ecosystem;
􀁹􇤠 Protect, conserve, recover, and restore fish, aquatic species, and their habitats in the North
Florida Ecosystem;
􀁹􇤠 Protect, conserve, and enhance wetlands in the North Florida Ecosystem;
􀁹􇤠 Protect, conserve, enhance, and recover listed and candidate threatened and endangered
species and their habitats; and
􀁹􇤠 Protect and manage units of the National Wildlife Refuge System and the National Fish
Hatchery System (U.S. Fish and Wildlife Service 1996).
REGIONAL CONSERVATION PLANS AND INITIATIVES
Numerous regional conservation plans and initiatives affect the refuge, in particular, Florida's
Comprehensive Wildlife Conservation Strategy. Florida’s Wildlife Legacy Initiative – Comprehensive
Wildlife Conservation Strategy – is part of a nationwide conservation effort in which State fish and
wildlife agencies collaborate with the Service to protect vulnerable habitat and species. It addresses
many of Florida's conservation threats and management issues. In addition, several regional level
conservation plans and initiatives also impact the management of the refuge’s resources, including
those listed (Figure 5 outlines conservation lands around the refuge).
􀁹􇤠 Future land use plans of Brevard and Volusia Counties
􀁹􇤠 State of Florida Greenway Plan
􀁹􇤠 SJRWMD Surface Water Improvement and Management Plan
􀁹􇤠 South Atlantic Marine Fisheries Council Fisheries Management Plan
􀁹􇤠 South Atlantic Marine Fisheries Council Ecosystem-Based Fisheries Management Plan
These plans were reviewed to ensure that common conservation goals were included in the CCP
development process.
Comprehensive Conservation Plan 17
Figure 5. Area conservation lands
18 Lake Woodruff National Wildlife Refuge
ECOLOGICAL THREATS AND PROBLEMS
Lake Woodruff NWR is in a key location, not only to serve and support biological diversity in the St.
Johns River basin and central Florida, but also to serve continental populations of migratory birds
along the Atlantic Flyway. Human impacts and underlying threats to biological diversity on and off the
refuge include the listed items.
􀁹􇤠 Direct loss of habitat due to development and other human activities;
􀁹􇤠 Simplification and degradation of remaining habitats, including habitat alteration and
fragmentation;
􀁹􇤠 Loss and decline of species and biological diversity;
􀁹􇤠 Effects of constructing navigation and water diversion facilities;
􀁹􇤠 Introduction and spread of non-native and nuisance species;
􀁹􇤠 Lack of environmental regulation and enforcement;
􀁹􇤠 Cumulative effects of land and water resource development projects;
􀁹􇤠 Ongoing wildlife disturbance due to development and other human activities; and
Impacts of non-point sources of pollution and water quality degradation.
As a result of these threats, some species endemic to the ecosystem have become extinct,
threatened, or endangered under the Endangered Species Act. Lake Woodruff NWR supports seven
federally threatened or endangered species that regularly occur on the refuge (eastern indigo snakes
and snail kites have not been documented on the refuge). Further, the refuge supports an additional
10 species listed by the State of Florida as either threatened, endangered, or of special concern.
(See Appendix I for a complete listing of these species.) [Nationally, 1,262 species are federally
listed with 986 listed as endangered (including 388 animals and 598 plants) and 276 listed as
threatened (including 129 animals and 147 plants). In addition, at least 257 species are listed as
candidates for Federal listing.]
Lake Woodruff NWR serves to protect, maintain, and enhance the high productivity and biological
diversity within the ecosystem. Increasing human population growth and impact have altered many
ecological characteristics of the St. Johns River basin. Lake Woodruff NWR faces ongoing threats
from contaminated air, soil, and water; from erosion and sedimentation; and from cumulative habitat
impacts from land and water resource development activities adjacent to the refuge. Rapid
population growth and development have resulted in long-term negative impacts to Lake Woodruff
NWR. These include increased boat traffic in the shallow waters of the St. Johns River and
associated lakes; increased use and development of natural resources in the area; habitat
fragmentation; and the introduction and spread of exotic species. Native terrestrial habitats that once
dominated uplands include hardwood hammocks, which are very important for mammals and
migratory birds. Urbanization and agricultural operations (e.g., ferneries) now dominate land uses in
upland areas along the DeLand Ridge. Historically sugar cane and other agricultural operations such
as cattle pastures dominated the area’s landscape, but these are quickly being replaced by urban
and suburban sprawl. Stormwater inputs, pollution, habitat destruction, and continual land and water
use practices are constant threats to fish and wildlife resources in this area. By the year 2015,
Florida is expected to have over 20 million residents, while the two-county (Lake and Volusia) area
around the refuge is anticipated to reach over 850,000 (Florida Housing Data Clearinghouse 2007).
PHYSICAL RESOURCES
The climate, geology and topography, soils, air quality, and hydrology and water quality form the
foundation of the physical environment of the refuge.
Comprehensive Conservation Plan 19
CLIMATE
General Climatic Conditions
The main factor influencing climate at Lake Woodruff NWR is its latitude. Its proximity to the Atlantic
Ocean also has an influence, but to a lesser extent. Generally, the climate can be described as
subtropical marked by short, dry and mild winters and hot, humid summers, lacking appreciable
spring or fall seasons.
Temperature
January is typically the coldest month of the winter season with average lows of 46ºF and highs near
71ºF. Below freezing temperatures occur several days each season, but generally last only a few
hours each day. Severe cold events with lows less than 20ºF occur on average every decade. The
latest locally severe freeze was in 1985, when a record low of 16ºF was established. During the
spring temperatures quickly rise with lows averaging almost 63ºF and highs reaching 90ºF towards
the end of the season. Average summer maxima are 90ºF and average minima reach 71ºF.
Temperatures above 100ºF are rare, most recently occurring in 2001 (102ºF). The fall is
characterized by cooler temperatures and average highs and lows are 82ºF and 61ºF, respectively.
Relative Humidity
The relative humidity (RH) is typically high on the refuge due to the presence of numerous freshwater
bodies and the proximity to the Atlantic Ocean. Mean dawn RH is between 88 and 95 percent
throughout the year, while readings in the mid-afternoon are between 55 and 67 percent. Very low
RH can occur with the passage of cold fronts in the winter. Readings in the 30 to 40 percent range
are common and a RH as low as 26 percent has been recorded. On the other end of the spectrum,
an RH of 100 percent is not uncommon with fog occurring 90 days per year on average.
Precipitation
Precipitation at DeLand averaged 55.5 inches/year with a standard deviation of 9.3 inches during the
period 1931-2005 (Southeast Regional Climate Center 2006). Of this average, over half falls during
June-September, with other months averaging between 2.2-4.5 inches. Summer precipitation is
driven mainly by convective activity, while frontal storms comprise the majority of rainfall events
during the winter.
Lightning
Because of its importance in fire management, a major refuge management activity, lightning
deserves a special mention. The National Weather Service (NWS) Office in Melbourne, Florida
states that Florida is the “lightning capital of the United States” (National Weather Service 2005). The
NWS data estimate that over 7,000 lightning strikes occur in Volusia County each year. Since the
establishment of Lake Woodruff NWR, lightning-induced fires have burned over 10,000 acres of
marsh. In addition, Lake Woodruff NWR’s headquarters has been struck at least three times,
resulting in damage to the telephone, base radio, and other electronic systems.
Wind
Wind is another important weather condition that greatly impacts Lake Woodruff NWR. Wind patterns
change throughout the day due to faster heating and cooling of the land relative to the ocean, as well
as due to erratic winds around thunderstorms. High winds commonly associated with cold fronts or
low-pressure systems, above 20 miles per hour (mph), are common in the winter and spring months,
with occasional days with 35 to 40 mph winds. Several days of light and variable winds can occur in
summer months when subsiding air is entrenched over the central Florida area. The "Storm of the
Century," which affected large areas of the eastern seaboard, hit Lake Woodruff NWR during the
early morning hours of March 13, 1993. Winds were recorded near 80 mph, and the community was
20 Lake Woodruff National Wildlife Refuge
without power for days. The high winds blew eaglets from both active nests, and three injured bald
eaglets were taken to the Audubon Bird of Prey Center for care and rehabilitation. In addition,
tropical storms and hurricanes have the potential to cause the most wind damage.
Tropical Cyclones
Tropical depressions, storms, and hurricanes can impact refuge activities and infrastructure. Large
amounts of rainfall can accompany tropical cyclones. In addition, wind and wave (lakeshore) action
can result in major damage to important refuge habitats. The refuge has been affected by over 15
tropical cyclones of various intensity since 1964, including three hurricanes in 2004 (Charley,
Frances, and Jeanne) and Hurricane Wilma in 2005. Storm effects include downed limbs and trees
and flooding of impoundments and public area parking areas.
GEOLOGY AND TOPOGRAPHY
Geology
Florida has a complex geologic history with repeated periods of deposition when the Florida Plateau
was submerged and with erosion during periods of lower sea level when the land was exposed
(Randazzo 1997). The course of the St. Johns River follows three geologic fault zones. These
structures are all post-Late Miocene (5.3 million years ago) in age. The Sanford-Palatka Offset, one
of the three faults, has a different history from the upper and lower St. Johns River. This older part of
the valley is incised in higher land cut during a low sea-level stand in Late Tertiary (1.6 million years
ago) or early Pleistocene times by what was believed to be an entrenched tributary of the Oklawaha
River (White 1958). The Oklawaha River flows out of still higher ground to the west and should
therefore antedate the St. Johns River. When sea levels rose the lowered surfaces were inundated
to become estuaries or sounds. The sediments deposited in them have become part of the modern
day floodplains of the St. Johns, Wekiva and Lower Oklawaha Rivers. Upon retreat of the inundating
sea, the St. Johns became an integrated stream flowing along the relict beach ridge plain to Lake
Harney and then veered westward to enter the Sanford-Palatka Offset. Lake Woodruff NWR is in the
northern portion of the Sanford-Palatka Offset, just south of Lake George. At Palatka, it re-enters the
same lower beach-ridge plain and follows it north again until it is deflected seaward by the delta of the
sediment-bearing St. Mary's River at Jacksonville. The presence of numerous beach ridges
characterizes the sediments in the basin as mostly sands, with very little clay and silt.
The boundary between the DeLand Ridge and the Sanford/Palatka Offset is mapped as a north
trending fault that is down thrown to the west. DeLeon Springs is close to or on the fault where an
east/west fracture crosses the fault. The two probably form permeability channels that funnel the
water to the spring. The spring, itself, appears to be an old sinkhole formed by dissolution of the
underlying limestone.
The average spring flow at DeLeon Springs from 1980 through 1992 is 16 million gallons per day and
ranges from 11 to 24 million gallons per day. The average annual trend indicates a decline in stream
flow since 1980. The spring-fed creek flows westward through a series of three shallow-water lakes
(Spring Garden, Woodruff, and Dexter) to the St. Johns River, 10 miles away, and is approximately
one foot above sea level (Denson 1995).
Topography and Soils
The eastern side of the refuge basically forms a transition area between the sandhills of the karst
DeLand Ridge System and the wetland floodplain of the St. Johns River. The topography generally
slopes zero to five degrees from east to west, from elevations of 35 feet above mean sea level (MSL)
on the refuge’s eastern boundary to five feet above MSL at the east edge of Lake Woodruff. The
average elevation of the marsh areas is approximately 6.5 feet above sea level.
Comprehensive Conservation Plan 21
Roughly 5,800 acres of hardwood swamps and drainages exist on the refuge. These wooded swamps
merge at the edge of the marshes and are also found where persistent drainages are formed through the
flatwoods. The elevations range from 12 inches to eight feet above sea level for this forest type.
The pine flatwoods and longleaf pine savannas are typically in areas of flat terrain on poorly drained
soils. Shallow drainages and ephemeral ponds exist throughout the area. Elevations on the refuge
for these forest types range from 10 to 30 feet above MSL.
The relatively small amount of xeric scrub oak/sand pine forest type is found only on the highest
elevations of the refuge, along the transition area between the flatwoods and the DeLand Ridge
System. Elevations are generally 30 to 35 feet above MSL. A small portion of this forest type is
within the headquarters unit with elevations between 50 and 80 feet above MSL.
Five orders and 17 soils series are found on the wooded areas of the refuge. The soils can generally
be classified as either wetland or upland.
Wetland Soils
Three soil orders are represented in the wetland areas of the refuge: Alfisols, Histisols, and Mollisols.
Alfisols are soils with loamy or clayey (alkaline) subsoils that underlie horizons with less clay. The
Histisols are soils with an organic horizon such as peat or muck. The water table is usually at or above
the surface during the wet season and within 10 inches of the surface during the rest of the year. Organic
matter content is high and natural fertility is moderate. The native vegetation is marsh grasses, maple,
gums, cypress, and other swamp species. The Mollisols are found on the low terraces along the St.
Johns River. They are frequently flooded and are saturated to the surface for much of the year. Fertility
is high and organic matter content is moderate. The natural vegetation is water plants and/or marsh
grass types, but some areas have hammocks populated by cabbage palm and live oak.
Upland Soils
Three soil orders (Alfisols, Entisols, and Spodisols) are found in the upland areas of the refuge. The
Alfisols are characterized by a higher pH in the upper horizons or an increasing pH as one goes down
through the soil profile. There are three soil series in this order on the refuge: the Holopaw, Pineda, and
Riviera. All of these soils are nearly level with water tables within 10 inches of the surface most of the
year. Fertility and organic matter content are low. The natural vegetation can be hardwoods along the
floodplains or slash pine with an understory of palmetto, wax myrtle, and wiregrass on the higher sites.
Entisols are soils that either have none of the diagnostic horizons found in the other soils or have only
the beginnings of them. There are three Entisols on the refuge: Orsina, Satellite, and Tavares series.
The Orsina and Tavares soils are well-drained deep sands with slopes ranging from zero to five
percent. Water tables are deep, 40 to 60 inches during the wet season, and greater than 60 inches in
dry periods. Fertility and organic matter contents are low. The natural vegetation is sand and
longleaf pine with an understory of scattered palmetto and other species. Currently, areas where
these soils are found are dominated by mature oak/sand pine scrub with small pockets of longleaf
pine flatwoods. The Satellite soil is somewhat poorly drained sand with slopes less than two percent.
The water table is within 10 to 40 inches of the surface during the wet season and around 60 inches
during the dry season. Fertility and organic matter content are low. The native vegetation is longleaf
pine with an understory of palmetto and wiregrass. At present, these soils are supporting mixed
conifer/hardwood stands with scrub oak and palmetto understories.
The third soil order in the wooded uplands is the Spodisols. These soils have a spodic horizon, which
is a zone of deposition within the soil profile where clay, iron, and aluminum oxides and organic
matter have accumulated. The Spodisols are the soils of the typical Florida flatwoods, although they
22 Lake Woodruff National Wildlife Refuge
are sometimes found in the low sandy ridges. There are seven Spodisols found on the refuge: the
Cassia, Daytona, Farmton, Immokalee, Myakka, Pomona, and Wabasso soil series. All of these soils
have slopes less than fiver percent. The Cassia and Daytona soils are found in areas between the
true flatwoods and the sand ridges. The water table is generally below 10 inches, even in the wettest
times, and can reach depths of from 40 to 70 inches during the dry season. Natural fertility is low, as
is organic matter content. The natural vegetation is sand, longleaf and slash pine, with some oaks
and palmetto. The Farmton, Immokalee, Myakka, and Wabasso soils are found in the true flatwoods.
Slopes are two percent or less. Water tables can be at or above the surface during the wet season,
and are generally above 40 inches throughout the year. Fertility and organic matter content are low.
The natural vegetation is slash and longleaf pine, with an understory of palmetto, oak, gallberry, and
wiregrass. The majority of the longleaf pine savannahs are found growing on these soil types. The
Pomona soil is found between the true flatwoods and the swamps, in poorly drained depressions.
This soil is nearly level. Water tables can be as much as 10 inches above the surface during the wet
season, and the soil is usually saturated to within 10 inches of the surface the rest of the year.
Fertility is low, and organic matter content is moderate. The natural vegetation varies, and can be a
mix of pond and slash pine with hardwoods.
Hydrology
St. Johns River
The primary surface waters on and around the refuge are part of the middle St. Johns River basin.
The St. Johns River is over 300-miles-long and encompasses a watershed of approximately 8,700
square miles. It flows from its origin near Vero Beach north to Jacksonville where it empties into the
Atlantic Ocean. The river's total drop from beginning to end is less than 30 feet, or about one inch
per mile, making it one of the "laziest" rivers in the world. The river’s low flow rate makes it
susceptible to a build-up of nutrients and other pollutants.
Upland Sheet Flow
Runoff from the refuge occurs in the form of sheet flow that concentrates into streams or groundwater
discharge such as that at DeLeon Springs. The gentle topography and permeable soils of the refuge
suggest that much precipitation is evaporated, transpired by plants or percolates to groundwater
relative to the amount that runs off. This is supported in general by Rutledge (1985). Water moves
through sheet flow from upland refuge areas toward the marshes and impoundments. Construction
of the railroad bed has impeded this natural flow, creating isolated ponds and wetlands east of the
tracks which drain via culverts onto the refuge.
Ground Water Hydrology
The refuge, including all of Lake Woodruff, is thought to be the recharge region for DeLeon Springs.
This second magnitude spring has a mean discharge of 27 cubic feet per second (CFS), with
maximum and minimum flows of 61.6 and 12.2 CFS over the period of record from 1961 to 2005.
Discharge does not vary greatly from month-to-month, but has been declining in recent years. This is
thought to be related to the general decrease in precipitation in Florida (FDEP 2000). The correlation
with precipitation, combined with water chemistry data collected by the SJRWMD, indicates this
spring water has a mixture of “young” water (less than 30 years old) mixed with water that has been
in the Floridan Aquifer for over 1,000 years (Toth 1999).
Gross-scale modeling has also been conducted that shows the entire refuge lies within a discharge
region, suggesting that during an average year, more water discharges from the ground than is added to
the aquifer (Rutledge 1985; Boniol et al., 1993). Nearby areas determined to be the recharge regions for
the Floridan Aquifer include all the ridge areas east and south of the refuge in the vicinity of DeLand, as
well as other relatively high-elevation parts of the region (Boniol et al., 1993).
Comprehensive Conservation Plan 23
Water Quality and Quantity
Water Quality
Water quality is a measure of the physical and chemicals characteristics of water. All animals and
plants have certain water quality requirements, depending on their life history stages, the season, and
other attributes. Water quality can be negatively influenced by humans through pollution.
No water body on Lake Woodruff NWR is currently listed as impaired under Section 303d of the Clean
Water Act, though the St. Johns River between Lake Dexter and Lake George is listed for low dissolved
oxygen and non-point source pollution limits known as total maximum daily loads (TMDLs) are being
developed for this reach of the river for nutrients, total dissolved solids, and dissolved oxygen.
Most groundwater in Florida is formed by rainwater percolating through soils and collecting in large
underground caves or reservoirs, called aquifers. Florida's aquifers are increasingly threatened by
human activities. In Florida, groundwater is particularly susceptible to contamination because the
water table is close to the surface and the limestone bedrock is permeable. Human and animal
bacteria, agricultural activities, pesticides and fertilizers, fuel spills, salt, and methane gas are human
impacts affecting groundwater quality. In certain areas of Florida, groundwater reaches the surface
naturally, via springs (e.g., DeLeon Springs). Pollution in areas where groundwater is formed
(recharge areas) can affect water quality in springs that may be many miles away.
Water Quantity
Water quantity in the form of rain, surface water, and groundwater has profound effects on vegetative
communities and associated wildlife species. On the refuge, water quantity generally decreases with
an increase in elevation.
Kinser and Minno (1995) conducted a study of soils and vegetation communities and the potential for
changes in these communities if groundwater levels were to be lowered. They found that although
the refuge has soils that are highly subject to dewatering and that these soils support vegetation
communities that are dependent upon these waters, the likelihood that there would be significant
changes to the communities is low because the refuge has low elevation and is located near large,
relatively stable water bodies. The study only addressed the question of groundwater withdrawals,
leaving open the question of changes due to increased surface withdrawals from the St. Johns River.
Air Quality
The air pollutants of major concern in Florida are carbon monoxide, lead, nitrogen dioxide, ozone,
particulate matter, and sulfur dioxide (FDEP 2004). The primary sources of these pollutants are
vehicle emissions, power plants, and industrial activities. In 2004, all areas of Florida were air quality
attainment areas (FDEP 2004). The Deland area is considered to have good air quality. However,
occasional temperature inversions lasting up to 48 hours can temporarily degrade local air quality
below acceptable levels
Lake Woodruff NWR is considered an attainment or clean area, under the Clean Air Act. The
ambient air quality is influenced by land management practices such as prescribed burning, vehicle
traffic, and off-site emission sources.
24 Lake Woodruff National Wildlife Refuge
BIOLOGICAL RESOURCES
HABITAT
The habitats on the refuge and their conditions are the end result of both the physical
environment and past human activities. The influence of human activity on the landscape has
been ongoing for thousands of years in certain parts of Florida. Native Americans probably did
little to modify the physical landscape, but may have modified ecological processes through their
use of fire. Native Americans used fire for various purposes, such as hunting and warfare
(Robbins and Myers 1992). The upland areas of Lake Woodruff NWR are considered to be part
of a fire driven ecosystem. Certain vegetation types are dependent on periodic fires. Habitats
and their respective acreages are listed in Table 1.
When European settlers arrived, they also varied the natural fire regime. They began to modify the
physical landscape, starting with the construction of roads, drainage ditches, and canals. The use of
the land for agriculture increased the construction of infrastructure, but major alterations to the
landscape did not occur until the 1950s. During the next several decades, fire was excluded from the
landscape. The vegetation on the land which is now the refuge became overgrown, reducing its
utility for some native wildlife.
Since the refuge was founded, much management has been conducted, including activities directed
towards restoring portions of the landscape to more natural conditions. Other management activities
maintained or modified the existing structures, such as the impoundments, to increase their function
and value to wildlife. The mix of upland, wetland, and aquatic habitats that are the end result of the
various natural and anthropologic phenomena are described. See Figure 6 for existing impoundment
management units and Figure 7 for the burn units.
Uplands
Areas are considered uplands if they are not subject to flooding on a regular basis or have standing
water for only limited periods of time. The transition from uplands to wetlands is gradual and, in some
cases, it is hard to determine into which category one should place some habitat types. Vegetation
types are shown in Figure 8.
Pine and Palmetto Flatwoods
Nearly one half of the upland forest on the refuge (~1,132 acres) is considered pine flatwoods. The
flatwoods range from mesic sites to scrubby flatwoods, depending upon soil type and elevation.
Flatwoods are characterized by a pure or predominate pine overstory (including slash, longleaf, and
pond pines), little midstory, and a dense, yet variable, understory. Mesic sites tend to have a higher
saw palmetto/gallberry component in the understory, whereas, scrubby flatwoods have a significant
oak component in the understory. In areas where fire has occurred infrequently or has been
suppressed, hardwoods may comprise up to 25 percent of the overstory. Fire suppression and/or
exclusive use of winter burning have led to saw palmetto becoming a dominant understory
component most of the flatwoods.
Longleaf Pine/Wiregrass Savanna
The longleaf pine/wiregrass savanna communities are found only within the southeast corner of the
refuge, within the southern half of the Volusia Tract Unit. The savannas are open pine stands (with
30 to 40 basal area) dominated by uneven-aged longleaf and slash pine of 80 to 100 feet tall with
little to no midstory trees and with a diverse herbaceous understory that is one to three feet tall. The
savannas on the refuge were most likely remnant grazing lands prior to establishment of the refuge.
Comprehensive Conservation Plan 25
Table 1: Habitat types and their associated acreages (based on GIS calculations from 2004
SJRWMD DOQQ’s)
Habitat Type Acres
Wetlands
Marsh 10,014
Willow Shrub 1,113
Impounded Marsh 445
Ephemeral Ponds 31
Hardwood Forests 6,767
Uplands
Pine/Palmetto Flatwoods 1,132
Hardwood/Mixed Conifer 404
Longleaf/Wiregrass Savannah 323
Hardwood Hammock 250
Palm Hammock 150
Oak/Sandpine Scrub 145
Aquatic
Open Water 757
Pond/Lake 43
Total 21,574
26 Lake Woodruff National Wildlife Refuge
Figure 6. Lake Woodruff NWR impoundment management units
Comprehensive Conservation Plan 27
Figure 7. Lake Woodruff NWR fire management units
28 Lake Woodruff National Wildlife Refuge
Figure 8. Lake Woodruff NWR vegetation types
Comprehensive Conservation Plan 29
Oak-Sand Pine Scrub
The oak-sand pine scrub forest type occurs on well-drained sandy soils found within the Eastside Unit
of Lake Woodruff NWR. This community is representative of a climax vegetative community for
sandhill soil areas that has been suppressed from fire. Fire suppression results in a prolific
reproduction of oak species, including Quercus virginiana, Q. geminata, Q. incana, Q. chapmanii, Q.
hemisphaeric, and Q. margaretta, as well as many other woody shrubs, such as Lyonia ferruginea,
Vaccinium arboretum, V. stamineum, Hypericum cistifolium, and Ilex glabora.
The canopy is formed primarily of live oak, sand live oak, and sand pine, 30-50 feet tall, forming a
dense, mainly closed canopy that limits understory diversity. Understory vegetation consists of
patchy saw palmetto, woody shrubs, and grasses. Ground cover is hardwood leaf litter, scattered
grasses, and herbaceous plants, including patchy areas of wiregrass and deer moss. Leaf litter is
one to three inches deep forming a continuous ground cover, while grasses and other forbs only form
about 10 percent of the ground cover.
Mixed Hardwood/Conifer
This forest type typically is formed in ruderal areas and in flatwoods that are transitioning to hardwood
forest due to fire suppression. This forest type is found primarily within the Eastside Unit. The dominant
tree species are typically slash pine and laurel oaks. The understory is sparse with patchy saw palmetto.
Hammocks
Hardwood Hammocks
Hardwood hammocks occur on mesic to xeric soils and represent a climax forest community. The
overstory in the hammock is typically mature live oak, 40 to 60 feet tall, forming a continuous canopy
cover, resulting in an open understory and leaf litter ground cover. This forest type provides excellent
mast production for wildlife. Fire return is infrequent and generally results in low-intensity ground fire
when it does burn.
Palm Hammocks
Palm hammocks occur in mesic and hydric transitional areas between wetlands and upland soils. On
the refuge, they are found primarily on Jones and Tick Islands and along marsh edges. The
dominant tree species is cabbage palm, forming 80 percent canopy closure and growing at maturity
to 70 feet. The understory can vary from sparse clumps of saw palmetto with leaf litter ground cover,
to a dense herbaceous cover of grasses and vines.
Wetlands
There are three distinct types of wetland vegetative communities represented on the refuge, each
dominated by unique vegetation: marshes, impoundments, and hardwood communities.
Open Marshes
The open grass marsh systems represent one of the largest and most expansive habitat types
(~10,000 acres) of the refuge. Marshes have fluctuating water levels, driven by surface water levels
and precipitation. They generally have unimpeded water flow on at least one side from an open body
of water. They are comprised primarily of cordgrass (Spartina bakerii) and sawgrass (Cladium
jamaicense), typically growing five to seven feet tall and forming dense, continuous beds. Many small
open water ponds and distinct drainages occur throughout the marshes.
30 Lake Woodruff National Wildlife Refuge
Impounded Marshes
Impounded water totaling 445 acres in three pools was created by the construction of dikes within the
cordgrass marsh and subsequent flooding. The resulting habitat is hemi-marsh, with 40-60 percent
open water and a dispersion of emergent vegetation. Water is manipulated seasonally in these
impoundments for the benefit of multiple species, including wading birds, waterfowl, and cranes.
Streams and Permanent and Ephemeral Wetlands
Scattered wetland areas are associated with the upland areas of the refuge. Many of the streams on
the eastern edge of the refuge are artificial and are a result of the culverts and drainage flows from
the CSX railroad bed. Grassy ponds are found in the flatwoods and are shallow depressions that are
seasonally or permanently flooded. In some cases, these areas have been invaded by wax myrtle,
willow, and other shrubs due to the lack of fire.
Wetland Hardwood Communities
Hardwood Swamp
The hardwood swamp areas have standing water for most, or all, of the year. They are dominated by
red maple and elm (Ulmus spp.), but may have cabbage palm, water-tolerant oaks, and water
hickory. This community makes up the greentree reservoir, an impounded bottomland forest.
Willow Swamp
Willow stands generally have standing water on them for most of the year and often occur on edges
and transitional areas. They are dominated by Carolina willow with some red maple and wax myrtle.
Often, willow encroaches into marsh habitats due to the lack of fire or to changes in hydrology. The
refuge has experienced a loss of open grass marsh habitat (~1000 acres) due to the encroachment of
willow and other shrubs since 1983.
WILDLIFE
Lake Woodruff NWR supports a high diversity of fish and wildlife species. This high biodiversity is, in
part, the result of the refuge’s location on an elevation gradient from the ancient DeLand Ridge dunes
down to the St. Johns River. The change in elevation corresponds to different hydrological regimes
and soils, which in turn support unique vegetative communities. However, the undeveloped nature of
the refuge’s landscape and diversity of habitats also contributes the high biodiversity. Upland and
freshwater wetland areas provide additional habitats to support a variety of species.
The refuge serves as a key area for biodiversity, species richness that is very important to the overall
ecological integrity and health of the St. Johns River and the North Florida Ecosystem. The Service
manages refuge resources and coordinates with neighboring land managers and agencies to
conserve biological diversity.
Invertebrates
No comprehensive survey of terrestrial or aquatic invertebrates present in refuge aquatic habitats has
been conducted. An invertebrate species of particular note occurring in refuge freshwater marshes
and impoundments is the freshwater snail known as the Florida apple snail (Pomacea paludosa).
The Florida apple snail is an important component in the food web of Florida's freshwater marshes,
serving as the primary food source for the endangered snail kite (Snyder and Snyder 1969, Hurdle
1973, Bennetts et al., 1994), as well as a food source for limpkins (Snyder and Snyder 1969), white
Comprehensive Conservation Plan 31
ibis (Kushlan 1974), boat-tailed grackles (Snyder and Snyder 1969), a variety of fish (Darby et al.,
1997), alligators (Delany 1986), and turtles (Dalrymple 1977). At least one Service report indicates
that one of the reasons for building impoundments on the refuge was to create habitat for the Florida
apple snail (U.S. Department of the Interior 1974).
Fish
The fish assemblages in aquatic habitats on the refuge are diverse, as would be expected from the
diversity of aquatic habitats present and the access to the Atlantic Ocean via the St. Johns River.
Approximately 101 species are thought to occur on the refuge, of which 6 are diadromous and 35 are
estuarine-dependent, with the remainder being resident freshwater native or exotic species.
Diadromous species are those that either reside in the ocean and spawn in inland freshwaters
(anadromous), or spawn in the ocean and use inland freshwaters as a nursery habitat (catadromous).
The American eel (Anguilla rostrata) and American shad (Alosa sapidissima) are two diadromous
species found on the refuge. Some marine species spawning offshore or in the downstream St.
Johns River estuary have estuarine- or riverine-dependent larval or juvenile stages which are likely
found in the lakes and stream runs that flow through the refuge. Representative families of estuarine-dependent
fishes which have been found on the refuge include Atherinopsidae (New World
silversides), Clupeidae (herrings), Mugilidae (mullets), Engraulidae (anchovies), Scianidae (drums),
Paralichthyidae (sand flounders), Gobiidae (gobies), and Eleotridae (sleepers). Resident freshwater
species conduct their life cycles entirely within refuge waters. Common resident species include blue
gill (Lepomis macrochirus), largemouth bass (Micropterus salmoides), Florida gar (Lepisosteus
platyrhincus), bowfin (Amia calva), and brown bullhead (Ameiurus nebulosus). A subset of resident
species such as blackbanded sunfish (Enneacanthus chaetodon), eastern mosquitofish (Gambusia
holbrooki), pigmy killifish (Leptolucania ommata), and swamp darter (Etheostoma fusiforme) is found
in the blackwater (waters resembling tea, heavily stained by tannin compounds from decaying
vegetation) habitats present in refuge swamp forests and some small streams. The final group
present includes species from other continents (i.e., non-native or exotic species) which have
established breeding populations, including blue tilapia (Oreochromis aureus), brown hoplo
(Hoplosternum littorale), and vermiculated sailfin catfish (Pterygoplichthys disjunctivus).
Reptiles and Amphibians
The refuge provides habitat to over 70 species of reptiles and amphibians. These include several
Federal listed species (i.e., American alligator and eastern indigo snake), as well as those listed by
the State (i.e., Florida pine snake, gopher frog, and gopher tortoise) (See Appendix I).
Amphibians
A May (2006) report states that frogs and toads are the most common and likely observed
amphibians on the refuge, in both aquatic and upland habitats. Some salamanders are likely present
in upland woods, but are not commonly observed. Sirens and amphiumas are present in refuge
canals and impoundments, but rarely seen. Amphibian species present or expected on the refuge
include 18 species of frogs and toads and 7 species of salamanders.
Frogs and Toads
Frogs and toads are abundant and diverse on the refuge (May 2006). May (2006) reports that
southern toads are fairly common in mesic hammock habitats on the refuge and can be seen hunting
after dark in grassy areas on the dikes adjacent to hammock habitat. They commonly breed on the
refuge. Oak toads are also present on the refuge, in open, scrubby woodlands with pines and oaks.
They also occur on Jones Island. Narrow-mouthed toads spend much of their time under cover in
hammock habitats. They are small, secretive frogs which prey on ants.
32 Lake Woodruff National Wildlife Refuge
At least five species of tree frogs are present on the refuge. Green tree frogs are common in
hammocks and marshes and along the edges of canals. They are generally found in vegetation near
permanent water bodies (Behler and King 1979). Squirrel tree frogs are found in the same habitats
as green tree frogs. Both green and squirrel tree frogs may be found on dwellings during warmer
weather, at night around exterior lights, hunting insects. The pinewoods tree frog tends to occur in
pine-dominated woods, or in hammocks near pine habitats. The spring peeper may be found in
mesic and hydric hammocks and in bottomland swamp habitats, calling from the wetter areas as early
as December (May 2006). The little grass frog is common in hammocks and in thick vegetation
around the edges of wetter habitats.
Pig frogs are large aquatic frogs that are abundant in the refuge’s canals and impoundments. They
may venture out onto dikes to feed after dark. The leopard frog is probably the most abundant frog
on the refuge, and is found in both permanent and semi-permanent wetlands. They also may feed on
impoundment dikes after dark. The refuge is within the reported range of the bullfrog, but it has not
been seen or heard on the refuge (T.M. Farrell, Department of Biology, Stetson University, personal
communication 2006).
Salamanders
Seven species of salamanders are thought to occur on the refuge: dwarf salamander (Eurycea
quadridrigitata), Southeastern slimy salamander (Plethodon grobmani), two-toed amphiuma
(Amphiuma means), greater siren (Siren lacertian), dwarf siren (Pseudobranchus striatus), lesser
siren (Siren intermedia), and peninsula newt (Notopthalmus viridescens).
Reptiles
The refuge hosts 11 species of lizards, 1 species of worm lizard, 12 species of turtles, 27 species of
snakes, and 1 crocodilian. The most commonly observed reptiles on the refuge include basking
American alligators and turtles, and the brown and green anole lizards, the latter often seen on the
ground in the impoundment parking lot and adjacent to refuge trails.
Lizards
Several species of lizard are found on the refuge, including two non-native species, the brown anole
(Anolis sagrei) and Indopacific gecko (Hemidactylus garnotii). Native species include the arboreal
green anole (Anolis carolinensis), as well as ground-dwelling species, such as broad-headed skinks
(Eumeces laticeps), glass lizards (Ophisaurus spp.), and fence lizards (Sceloporus undulates).
The Florida worm lizard (Rhineura floridana) is a legless, pink lizard which resembles an earthworm.
It is rarely seen. It lives primarily underground and searches for earthworms and termites, but also
preys on spiders (Behler and King 1979). Its preferred habitat is dry, sandy soil (Conant 1975).
Snakes
Twenty-seven species of snakes are presently documented on the refuge, including four venomous
species. The refuge has a particularly healthy population of dusky pigmy rattlesnakes (Sistrurus
miliarius barbouri), which have been the subject of research for many years (T.M. Farrell, personal
communication; Aycrigg et al., 1997; Bishop et al., 1996; Cheatwood et al 2003; Farrell 2006; Farrell
et al., 1995; Glaudus et al., 2005; Greene et al., 2002; Jemison et al., 1995; May 2006; May et al.,
1996, 1997; May and Farrell 1997; Rabatsky and Farrell 1996; Roth et al., 1999; and Rowe et al.,
2002). Their population density on the refuge is especially high. Individuals are active all year-round
(May et al., 1996) and are found primarily in drier habitats, often utilizing gopher tortoise burrows.
Other venomous snakes include the eastern coral snake (Micrurus fulvius), eastern diamondback
rattlesnake (Crotalus adamanteus), and Florida cottonmouth (Agkistrodon piscivorus) (May 2006).
Comprehensive Conservation Plan 33
Aquatic snakes that occur on the refuge include the banded water snake (Nerodia fasciata
pictiventris), brown water snake (Nerodia taxispilota), Florida green water snake (Nerodia floridana),
and striped crayfish snake (Regina alleni) (May 2006). Terrestrial species include the yellow rat
snake (Elaphe obsoleta quadrivittata), rough green snake (Opheodrys aestivalis), southern ring-necked
snake (Diadophis punctatus), Florida red-bellied snake (Storeria occipitomaculata), Florida
crowned snake (Tantilla relicta), scarlet snake (Cemophora coccinea), scarlet king snake
(Lampropeltis triangulum), pinewoods snake (Rhadinea flavilata), black racer (Coluber constrictor),
and coachwhip (Masticophis flagellum flagellum) (May 2006).
Turtles
Turtles are another highly visible component of the refuge’s herpetofauna and include mostly aquatic
and semi-aquatic species such as the Peninsula cooter (Pseudemys floridana peninsularis), Florida
red-bellied turtle (Pseudemys nelsoni), chicken turtle (Deirochelys reticulata), Florida box turtle
(Terrapene carolina bauri), snapping turtle (Chelydra serpentina), striped mud turtle (Kinosternon
bauri), stinkpot (Sternotherus odoratus), and Florida soft-shell turtle (Apalone ferox), as well as the
gopher tortoise (Gopherus polyphemus), which is the only truly terrestrial species.
Birds
Part of the Atlantic Flyway, the refuge is an important overwinter and stopover area for waterfowl,
shorebirds, and neotropical migratory birds. The refuge’s impoundments also serve an important
role for waterfowl, since no hunting is allowed. In total, over 230 species of birds can be found
using the refuge seasonally (Appendix I). This includes a number of Federal and State listed bird
species (Appendix I).
Landbirds
Through its conservation assessment process, Partners-in-Flight has identified numerous landbird
priorities for Bird Conservation Region 31 – Peninsular Florida. Priority landbirds found at Lake
Woodruff NWR, and to which the refuge can contribute meaningfully to the conservation of, include
swallow-tailed kite, American kestrel (Paulus sp), Chuck-will’s-widow, and Northern bobwhite.
Numerous other species are identified as priorities for Peninsular Florida that are known or likely to
occur within the refuge, but because of their inconspicuousness or due to a general lack of
quantitative abundance data, it remains unclear to what extent they occur on the refuge or how the
refuge might contribute to their conservation. These species include brown-headed nuthatch,
prothonotary warbler, Bachman's sparrow, Henslow's sparrow, grasshopper sparrow, LeConte's
sparrow, painted bunting, and common ground dove.
Shorebirds
Lake Woodruff NWR was identified in the Southeastern Coastal Plain – Caribbean Shorebird
Conservation Plan (Southeast SCP) as a refuge with the potential to provide important stopover
habitat for shorebird migration through Florida. Shorebird species of concern identified in the
Southeast SCP include snowy plover, Wilson's plover, piping plover, American oystercatcher,
marbled godwit, red knot, semipalmated plover, stilt sandpiper, buff-breasted sandpiper, and short-billed
dowitcher. None of these species are likely to breed at Lake Woodruff NWR, however, the
refuge provides excellent foraging habitat for spring and fall migrating, and for any over-wintering
birds. Although the refuge does not support breeding populations of the highest priority species, its
role in providing stopover habitat during spring and (especially) fall migrations should not be
understated. Availability of foraging habitats during key migratory periods has been shown to be
critical for the persistence of long-distance migratory shorebird species. Thus, one habitat goal stated
in the Southeast SCP is to provide dedicated, high-quality managed habitat to support energetic
requirements of in-transit migratory birds.
34 Lake Woodruff National Wildlife Refuge
Waterfowl
Lake Woodruff NWR was originally established as a waterfowl refuge. Twenty-two species of ducks
and geese have been recorded, but waterfowl have never used the refuge in large numbers. The
most common species are blue-winged and green-winged teal that may number several thousand
during fall and winter (September – March). Wood ducks are a year-round resident species, utilizing
hardwood swamp habitats for breeding and foraging. It is difficult to estimate numbers of this species
and it is not known what the wood duck population may be on the refuge (breeding or wintering).
Hooded mergansers and ring-necked ducks occur as wintering species, although not frequently or in
large numbers. The refuge's impoundments and natural marshes have the potential to provide
foraging and nesting habitat for these and other waterfowl species.
Wading Birds
Several species of wading birds (e.g., egrets, herons, and ibises) can be found on the refuge.
Wading birds utilize a broad range of wetland habitat types for foraging, roosting, and nesting.
Refuge habitats frequented by wading birds include both natural and man-made features, including
natural freshwater wetlands, impoundments, and roadside ditches where they search for prey,
including fishes, amphibians, small reptiles, and insects. Wading birds on the refuge include a variety
of species, ranging from the large great blue heron (Ardea herodias) and great egret (Ardea alba) to
medium-sized species which include snowy egrets (Egretta thula), little blue heron (Egretta caerulea),
and non-native cattle egrets (Bubulcus ibis). The smallest egret species on the refuge is the
secretive, green heron (Butorides virescens). Two rare wading bird species which are found on the
refuge include wood stork (Mycteria Americana) and limpkin (Aramus guarauna).
Mammals
The mammalian fauna of the refuge is characteristic of the North Florida Ecosystem. Thirty mammal
species are known to occur on the refuge, including a marine mammal, the West Indian manatee
which frequents the St. Johns River and nearby spring waters. Another aquatic mammal, the otter
(Lutra Canadensis) is a carnivore which feeds on fishes and crayfish in refuge streams, ditches, and
impoundments. Large terrestrial carnivores include white-tailed deer (Odocoileus virginianus), and
bobcat (Lynx rufus). Medium-sized mammals commonly found on the refuge include raccoon
(Procyon lotor), opossum (Didelphis virginiana), and rabbits (Sylvilagus floridanus). Small mammals
include several species of moles, voles, shrews, mice, rats, and bats.
Rare, Threatened, and Endangered Species
Seven federally listed species occur on the refuge, as well as a number of State-imperiled species
and species of management concern (Table 2). Federally listed species include the West Indian
manatee, snail kite, wood stork, eastern indigo snake, American alligator, and whooping crane.
Table 2: Lake Woodruff NWR listed species
Common Name Scientific Name Status
FWC FWS
REPTILES
Gopher Tortoise Gopherus polyphemus T
Florida Pine snake Pituophis melanoleucus mugitus SSC (2)
Eastern Indigo Snake Drymarchon corais couperi T T
American Alligator Alligator mississippiensis SSC (1,3) T (S/A)
Comprehensive Conservation Plan 35
Common Name Scientific Name Status
FWC FWS
MAMMALS
Florida Manatee Trichechus manatus E E
Florida Black Bear Ursus americanus floridanus T
BIRDS
Limpkin Aramus guarauna SSC (1) SMC
Snowy Egret Egretta thula SSC (1)
Little Blue Heron Egretta caerulea SSC (1,4) SMC
Tricolored Heron Egretta tricolor SSC (1,4)
White Ibis Eudocimus albus SSC (2) SMC
Florida Sandhill Crane Grus Canadensis pratensis T
Whooping Crane Grus Americana E, SSC (5) E, EXPN
Wood Stork Mycteria Americana E E
Roseate Spoonbill Platalea ajaja SSC(1,4)
American Bittern Botaurus lentiginosus SMC
Black Rail Laterallus jamaicensis SMC
Semipalmated Sandpiper Calidris pusilla SMC
Short-billed Dowitcher Limnodromus griesus SMC
Black Tern Chlidonias niger SMC
Snail Kite Rostrhamus sociabilis plumbeus E E
Swallow-tailed Kite Elanoides forficatus SMC
Southeast American Kestrel Falco sparverius paulus T SMC
Common Ground-Dove Columbina inca SMC
Chuck-will’s-widow Caprimulgus carolinensis SMC
Red-headed Woodpecker Melanerpes erythrocephalus SMC
Loggerhead Shrike Lanius ludovicianus SMC
Brown-Headed Nuthatch Sitta pusilla SMC
Yellow-throated Warbler Dendroica dominica SMC
Prairie Warbler Dendroica discolor SMC
Bachman’s Sparrow Aimophila aestivalis SMC
36 Lake Woodruff National Wildlife Refuge
American Alligator
The American alligator (Alligator mississippiensis) is federally listed as threatened only as a result
of its similarity in appearance to the federally endangered American crocodile. The species is not
regulated under Section 7 of the Endangered Species Act and is not in danger of becoming
extinct. The species is listed as one of special concern by FWC. American alligators are
abundant on the refuge, with an estimated population of over 3,000 individuals (Allan Woodward,
Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute,
Gainesville, pers. comm., July 2006).
American alligators are abundant in all the impoundments and canals of the refuge (May 2006) and in
Lake Woodruff and the associated spring runs (Allan Woodward, Florida Fish and Wildlife
Conservation Commission, Fish and Wildlife Research Institute, Gainesville, personal
communication). The population in Lake Woodruff is used as an alligator reference area by the FWC
and the United States Geological Survey Florida Cooperative Fish and Wildlife Research Unit
(FCFWRU). Research on the alligator population has been conducted since 1981 on alligator
harvest effects (1981-1991), alligator egg viability, and adult alligator mortality.
The population is relatively dense, with all size classes well represented and with moderate nest
densities. The lake has a relatively clean drainage, with low levels of agriculture and no major
sources of industrial pollution. Poaching protection is provided by FWC law enforcement and habitat
protection is provided due to the presence of the refuge.
Annually, FWC conducts alligator nest surveys on Lake Woodruff NWR. Favorite sites are Tick
Island, Mud Lake, and Spring Garden Lake, as well as banks of the man-made canal adjacent to
Spring Garden Run. The alligators use cordgrass and saw grass as the primary nesting materials,
and prefer marsh habitat for nesting. A major prey species of the Lake Woodruff alligator population
is largemouth bass (Allan Woodward, Florida Fish and Wildlife Conservation Commission, Fish and
Wildlife Research Institute, Gainesville, pers. comm., 2006)
Overall, despite some chemical contamination in their tissue, the alligator population at Lake
Woodruff NWR is very healthy (Allan Woodward, Florida Fish and Wildlife Conservation Commission,
Fish and Wildlife Research Institute, Gainesville, pers. comm., 2006.). Hunting of alligators and egg
collections are presently prohibited on the refuge, but are allowed in adjacent areas.
Eastern Indigo Snake
Although the eastern indigo snake (Drymarchon corais couperi) is documented from Volusia, Lake,
Marion and Putnam Counties, literally surrounding the refuge (Ashton and Ashton 1988), no valid
documented records exist from the refuge itself (T.M. Farrell, pers. comm. 2006). The one reported
specimen is thought to have been a released animal. Despite the lack of documented records,
reference literature reports the species is present on the refuge (see Alden et al., 1998, page 394,
which states that the refuge supports the species).
Bald Eagle
The refuge currently supports an annual average of two to three breeding pairs of the recently
delisted southern bald eagle. And, nearby nesting eagles are known to use the refuge. Eagles are
known to use various pine flatwoods habitats within the refuge and have used mature live pine for
nest sites. Bald eagles have been shown to nest within the vicinity of large water bodies, particularly
with abundant access to fish and migratory waterfowl. The refuge’s wetlands provide a diversity of
excellent foraging habitats.
Comprehensive Conservation Plan 37
Snail Kite
Lake Woodruff NWR is not known to regularly support a significant portion of the snail kite population.
However, maintaining favorable foraging habitat conditions will allow for use of the area and may
provide critical foraging areas during periods when the southern Florida wetlands, that snail kites
normally rely upon, are unsuitable due to regional drought or other factors.
Wood Stork
The federally endangered wood stork (Mycteria americana) is of special interest to the Service.
Wood stork populations have declined sharply in Florida, from 60,000 in the 1930s to 5,000 pairs
today (USFWS 1986). Lake Woodruff NWR at one time supported a wood stork nesting colony.
Currently two colonies’ core foraging areas include the refuge. One colony is six miles to the
northeast of the refuge at Lake Disston and the other is five miles to the south at Hontoon Island.
The Lake Disston colony currently supports over 100 nesting pairs of wood storks and the Hontoon
Island colony supports over 50 nesting pairs.
Whooping Crane
Two separate whooping crane reintroduction projects target central Florida habitats. The FWC’s non-migratory
whooping crane reintroduction project is centered in south-central Florida (in the Kissimmee
Prairie Basin), however, dispersal includes the upper and middle reaches of the St. Johns River
basin. The Whooping Crane Eastern Partnership’s (WCEP) project targets central Wisconsin as the
breeding area, with a migration to western central Florida as the wintering area. These birds disperse
throughout central and north Florida, including the middle reaches of the St. Johns River and Lake
Woodruff NWR. A whooping crane pair from the migratory flock has established its winter territory on
the refuge. It utilizes the impoundments and marshes of pools 2 and 3, as well as nearby agricultural
lands, for roosting and foraging. The pair of whooping cranes that utilizes the refuge for its winter
territory is reproductively active and may be one of the first pairs from the migratory flock
reintroduction project to bring the historic first wild born chick on a fall migration to Florida. Whooping
crane chicks normally stay with their parents through the winter. During the winter, the parents teach
the chicks where and how to forage and also to roost in water at night to reduce the risk of predation.
Wild whooping crane juveniles normally separate from their parents either during the spring migration
or shortly after arrival on the nesting grounds, as observed in the birds from Aransas, Texas.
Whooping and sandhill cranes prefer open wet prairie, wet pasture, and large shallow water wetlands and
impoundments. Much crane habitat in central Florida has been lost to development in recent years and it
continues to be targeted for future development. Three of the four release sites the FWC has used for its
reintroduction project are now in various stages of development, as are other large ranches known to be
used by whooping cranes. Crane habitat appears to be on the decline in Florida.
West Indian Manatee
Refuge waters serve primarily as a safe harbor and feeding site for several West Indian manatees
(Trichechus manatus) year-round. The largest source of manatee mortality is boat collisions.
Navigable waterways on the refuge have established manatee protection zones (boat speed limits).
These areas are identified by signs and FWC is responsible for enforcement.
The portion of the St. Johns River that flows through the refuge is known as the Upper St, Johns
River Manatee Management Unit. The Upper St. Johns River has shown strong manatee population
growth between 1990 and 1999, increasing at an annual rate of 6.2 percent (Runge et al., 2004).
This growth rate is supported by high survival and reproductive rates. This is the smallest of the four
management units, contributing less than 5 percent of the total Florida manatee population, but the
Upper St. Johns is the fastest growing management unit (FWC 2007). Blue Spring is the primary
warm-water refuge used by the vast majority of the Upper St. Johns River Management Unit
38 Lake Woodruff National Wildlife Refuge
manatees, with winter counts regularly exceeding 100 animals (FWC 2007). The stable 23ºC warm-water
habitat provided by Blue Spring is a key factor in this population growth. Manatees also utilize
DeLeon Springs, though in much smaller numbers than Blue Spring. During the winter of 2006, 25
animals were observed using DeLeon Springs, while four were counted in the winter of 2007 (D.
Collins, DeLeon Springs State Park, pers. comm., April 19, 2007). The continued recovery of this
portion of the manatee population is dependent upon adequate warm-water delivery to this system.
The tenuous nature of artificial warm-water refugia in the Atlantic region, which exchanges a few
individual manatees with the Upper St. Johns region, elevates the importance of Blue Spring and
nearby springs to sustain a healthy manatee population into the foreseeable future.
Gopher Tortoise
Gopher tortoises (Gopherus polyphemus) live in dry, upland habitats where they dig burrows.
Several other species (collectively called “commensals”) utilize these burrows, such as frogs, other
turtles, poisonous and non-poisonous snakes, many small mammals, and even some birds like the
Florida scrub-jay and burrowing owl. Some of these commensals are legally protected species,
which adds to the ecological value that the tortoise burrow has in the ecosystem. Gopher tortoises
are protected under State law due to their decline in Florida where they are listed as Threatened.
Threats to these long-lived animals include habitat destruction, road mortality, disease, and
predation. Several dozen gopher tortoises are found on the refuge, primarily along the eastern
boundary and Volusia Tract.
Sandhill Crane
Sandhill cranes (Grus canadensis) are primarily birds of open freshwater wetlands and shallow
marshes, but may utilize a broad range of other habitat types, from bogs, sedge meadows, and fens
to open grasslands, pine savannahs, and cultivated lands. Sandhill cranes are omnivorous, feeding
on a wide variety of plant materials, including waste grains, and small vertebrates and invertebrates,
both on land and in shallow wetlands. The leading threat to this State listed species is the loss and
degradation of wetland habitats, especially ecological and hydrological changes in important staging
areas. Lead and mycotoxin poisoning, abnormal predation pressures, and collisions with fences,
vehicles, and utility lines are of local concern for various populations. At Lake Woodruff NWR,
sandhill cranes are found primarily in the freshwater marshes and impoundments, and occasionally
breed on the refuge.
Florida Pine Snake
The Florida pine snake (Pituophis melanoleucus mugitus) is a State protected species, which lives in
areas with relatively open canopies and dry sandy soils, in which it burrows. Habitats include
sandhill, oldfields, and pastures, but also sand pine scrub and scrubby flatwoods. It often coexists
with pocket gophers and gopher tortoises. Threats include collection for pets (now restricted);
highway mortality; and habitat loss and fragmentation from development, intensive agriculture, and
mining. This species has not been documented on Lake Woodruff NWR, but it is found in its vicinity
and suitable habitat does exist on the refuge.
Florida Black Bear
The Florida black bear (Ursus americanus floridanus) is State listed and Florida’s largest land animal.
A wide variety of forested communities are needed to support the varied seasonal diet of black bears.
Forested wetlands are particularly important for diurnal cover. This species requires a large home-range,
which makes it particularly vulnerable to habitat destruction and fragmentation, and resulting
road mortality. Several Florida black bears utilize portions of the refuge.
Comprehensive Conservation Plan 39
Swallow-tailed Kite
Swallow-tailed kites (Elanoides forficatus) are State listed birds which utilize a variety of wetlands
to feed on large insects. This species has declined due to destruction and alteration of
freshwater marshes. The refuge is home to the second largest pre-migratory roost of swallow-tailed
kites in the United States. Kites congregate and feed on the refuge in the summer before
beginning their migratory journey to South America. Therefore, it is an international area of
importance for this imperiled species.
Limpkin
The limpkin (Aramus guarauna) is a secretive bird of swamps and marshes. This bird reaches the
northern limits of its breeding range in Florida. There, it feeds almost exclusively on apple snails,
which it extracts from their shells with its long bill. This species can be found in open freshwater
marshes; swamp forests; and shores of rivers, lakes, and ponds. Once abundant in Florida, the
limpkin was almost eradicated by humans hunting for food. Conversion of wetlands for agriculture,
flood control, and development has further contributed to the species' decline in Florida. It is a State
listed species which can be found on the refuge.
Plants
The refuge includes a diverse number of habitats, which each support a large number of herbaceous
and woody plants. However, no exhaustive floral inventory of the refuge exists, and therefore
information on refuge plants is scarce. A 2002 wetlands inventory revealed a threatened endemic,
State listed scrub species, Garberia heterophylla (USGS 2002). It is likely that several other endemic
and rare plants occur on the refuge, but their occurrences are unknown.
Exotic, Invasive, and Nuisance Species
Exotic or non-native species are those which have colonized areas outside their natural range
(usually through human actions). Having left their original predators and disease behind, the
populations of many exotic species grow unchecked in their new environments, often becoming an
ecological threat to native biological communities. Lake Woodruff NWR has several non-native plants
and animals (Table 3).
Lake Woodruff NWR is located in north-central Florida, and due to periodic freezes, is located well
north of the ranges of many of the problematic species found in south Florida, which include Brazilian
pepper, melaleuca (Melaleuca quinquenervia), and Australian pine (Casuarina spp.). However, there
may be some non-native plants and animals that make their way down from the north, and therefore
the refuge has the potential to be impacted by the spread of both temperate and sub-tropical species.
The spread of many of these non-natives is increasing every year, and it is just a matter of time
before the occurrence of these species increases. Most of the terrestrial non-native plants such as
air potato (Dioscorea bulbifera), kudzu (Pueraria lobata), and Johnson grass (Sorghum halepense)
invade the refuge from the eastern boundary, where human development is increasing, and a highly
disturbed railroad easement allows non-native species to flourish. Non-native aquatic plants, such as
water hyacinth (Eichhornia crassipes), water lettuce (Pistia stratiotes), and hydrilla (Hydrilla
verticillata) are managed by the U.S. Army Corps of Engineers’ use of herbicides.
The Florida Exotic Pest Plant Council has categorized non-native plants in terms of their ecological
threats. Category 1 exotics are those which alter native plant communities by displacing native
species, changing community structures or ecological functions, or hybridizing with natives. Category
2 invasive exotics have increased in abundance or frequency but have not yet altered Florida plant
communities to the extent shown by Category 1 species. Many of the non-native exotics found on
the refuge are either Category 1 or 2 plants (Table 3).
40 Lake Woodruff National Wildlife Refuge
Exotic animals are also found on the refuge and have colonized a range of habitats from aquatic
areas to upland forests. The Asian clam (Corbicula fluminea) inhabits the waterways and
impoundments. Non-native fish, such as armored catfish (Pterygoplichthys spp.), brown hoplo
(Hoplosternum littorale), and tilapia (Oreochromis spp.), have been documented on the refuge and
are prevalent throughout the waters of the St. Johns River. They are impossible to eradicate, and
their effects on native fauna are not fully understood. Terrestrial species include feral hogs (Sus
scrofa), cats (Felis silvestris catus), dogs (Canis lupus familiaris), coyote (Caniss latrans), armadillos
(Dasypus novemcinctus), Cuban tree frogs (Osteopilus septentrionalis), brown anoles (Anolis sagrei),
and Eurasian collared doves (Streptopelia decaocto). These non-native animals can alter habitats,
prey on native species, and may compete for food and nesting sites with native wildlife.
Table 3: Lake Woodruff NWR non-native plants and animals
Scientific Name Common Name Category
Plants
Albizia julibrissin Mimosa, Silk Tree I
Ardisia crenata Coral Ardisia I
Bambusa spp. Bamboo NA
Broussonetia papyrifera Paper Mulberry II
Cinnamomum camphora Camphor-tree I
Dioscorea bulbifera Air-Potato I
Eichhornia crassipes Water-Hyacinth I
Hydrilla verticillata Hydrilla I
Imperata cylindrical Cogon Grass I
Lantana camara Lantana I
Lygodium japonicum Japanese Climbing Fern I
Melia azedarach Chinaberry Tree II
Myriophyllum spicatum Eurasian Water-milfoil II
Panicum repens Torpedo Grass I
Paspalum notatum Bahia Grass NA
Pistia stratiotes Waterlettuce I
Pueraria Montana Kudzu I
Sapium sebiferum Chinese Tallow Tree I
Sorghum halepense Johnson grass NA
Urena lobata Caesar's weed II
Animals
Anolis sagrei Brown Anole NA
Bubulcus ibis Cattle Egret NA
Comprehensive Conservation Plan 41
Scientific Name Common Name Category
Canis familiaris Feral Dog NA
Canis latrans Coyote NA
Corbicula fluminea Asian Clam NA
Dasypus novemcinctus Armadillo NA
Felis silvestris catus Feral Cat NA
Hoplosternum littorale Brown Hoplo NA
Oreochromis spp. Tilapia NA
Osteopilus septentrionalis Cuban Tree Frog NA
Passer domesticus English Sparrow NA
Pterygoplicththys spp. Armored Catfish NA
Streptopelia decaocto Eurasian Collard Dove NA
Sturnus vulgaris Starling NA
Sus scrofa Feral Hog NA
CULTURAL RESOURCES
Archaeological evidence suggests that the St. Johns River basin, which includes the refuge, has
been inhabited for over 12,000 years (Milanich 1998). Paleoindians were nomadic hunters who
made use of the riparian habitats during the much drier glacial period, which ended approximately
9,500 years before present (BP). This period was followed by the Archaic Period (9,500 – 4,000 BP),
which was characterized by a significant warming of the global climate during which sea-levels rose
and estuaries and rivers expanded. The mega-fauna of the glacial periods disappeared from Florida.
In response, native inhabitants switched to utilizing aquatic resources and established more
permanent settl