Draft Comprehensive Conservation Plan and Environmental Assessment Sandy Point, Green Cay, and Buck Island National Wildlife Refuges

              DRAFT COMPREHENSIVE CONSERVATION PLAN
AND ENVIRONMENTAL ASSESSMENT
SANDY POINT, GREEN CAY, AND BUCK ISLAND
NATIONAL WILDLIFE REFUGES
United States Virgin Islands
Caribbean Islands National Wildlife Refuge Complex
U.S. Department of the Interior
Fish and Wildlife Service
Southeast Region
Atlanta, Georgia
August 2009
Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
Table of Contents i
TABLE OF CONTENTS
SECTION A. DRAFT COMPREHENSIVE CONSERVATION PLAN
I. BACKGROUND ................................................................................................................................ 1
Introduction .................................................................................................................................. 1
Purpose and Need for the Plan .................................................................................................... 1
U.S. Fish and Wildlife Service ...................................................................................................... 2
National Wildlife Refuge System .................................................................................................. 2
Legal and Policy Context .............................................................................................................. 4
National and International Conservation Plans and Initiatives ..................................................... 5
Relationship to Island Territory Wildlife Agencies ........................................................................ 6
II. OVERVIEW OF THE REFUGES ...................................................................................................... 9
Introduction .................................................................................................................................. 9
History and Purposes of the Three Refuges ................................................................................ 9
Special Designations .................................................................................................................. 16
Ecosystem Context ..................................................................................................................... 16
Regional Conservation Plans and Initiatives .............................................................................. 17
Ecological Threats and Problems ............................................................................................... 18
Physical Resources .................................................................................................................... 20
Climate .............................................................................................................................. 20
Geology and Topography .................................................................................................. 22
Soils ................................................................................................................................. 24
Hydrology, Water Quality and Quantity ............................................................................. 29
Air Quality .......................................................................................................................... 31
Biological Resources .................................................................................................................. 32
Habitat ............................................................................................................................... 32
Wildlife ............................................................................................................................... 37
Cultural Resources ..................................................................................................................... 60
Sandy Point National Wildlife Refuge, St. Croix ................................................................ 61
Green Cay National Wildlife Refuge, St. Croix .................................................................. 62
Buck Island National Wildlife Refuge, St. Thomas ............................................................ 62
Socioeconomic Environment ...................................................................................................... 63
Refuge Administration and Management ................................................................................... 67
Sandy Point National Wildlife Refuge, St. Croix ................................................................ 67
Green Cay National Wildlife Refuge, St. Croix .................................................................. 74
Buck Island National Wildlife Refuge, St. Thomas ............................................................ 76
III. PLAN DEVELOPMENT ................................................................................................................. 79
Overview of the Planning Process .............................................................................................. 79
Summary of Issues, Concerns, and Opportunities ..................................................................... 79
Sandy Point National Wildlife Refuge, St. Croix ................................................................ 80
Green Cay National Wildlife Refuge, St. Croix .................................................................. 83
Buck Island National Wildlife Refuge, St. Thomas ............................................................ 85
Wilderness Review ..................................................................................................................... 87
ii Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
IV. MANAGEMENT DIRECTION ........................................................................................................ 89
Introduction ............................................................................................................................... 89
Refuge Visions ........................................................................................................................... 89
Sandy Point National Wildlife Refuge, St. Croix ............................................................... 89
Green Cay National Wildlife Refuge, St. Croix ................................................................. 90
Buck Island National Wildlife Refuge, St. Thomas ............................................................ 90
Goals, Objectives, and Strategies .............................................................................................. 91
Sandy Point National Wildlife Refuge, St. Croix ......................................................................... 91
Fish and Wildlife Population Management........................................................................ 91
Habitat Management....................................................................................................... 100
Resource Protection ....................................................................................................... 102
Visitor Services ............................................................................................................... 105
Refuge Administration .................................................................................................... 109
Green Cay National Wildlife Refuge, St. Croix ......................................................................... 113
Fish and Wildlife Population Management...................................................................... 113
Habitat Management....................................................................................................... 115
Resource Protection ....................................................................................................... 116
Visitor Services ............................................................................................................... 117
Buck Island National Wildlife Refuge, St. Thomas ................................................................... 118
Fish and Wildlife Population Management...................................................................... 118
Habitat Management....................................................................................................... 120
Resource Protection ....................................................................................................... 122
Visitor Services ............................................................................................................... 123
V. PLAN IMPLEMENTATION ........................................................................................................... 125
Introduction .............................................................................................................................. 125
Current and Proposed Projects ................................................................................................ 125
Fish And Wildlife Population Management – Sandy Point NWR .................................... 125
Fish And Wildlife Population Management – Green Cay NWR ...................................... 128
Fish And Wildlife Population Management – Buck Island NWR ..................................... 128
Habitat Management – Sandy Point NWR ...................................................................... 129
Habitat Management – Green Cay NWR ........................................................................ 130
Habitat Management – Buck Island NWR ...................................................................... 131
Resource Protection – Sandy Point NWR ...................................................................... 131
Resource Protection – Green Cay NWR ........................................................................ 132
Resource Protection – Buck Island NWR ....................................................................... 133
Visitor Services – Sandy Point NWR .............................................................................. 133
Visitor Services – Green Cay NWR ................................................................................ 134
Visitor Services – Buck Island NWR ............................................................................... 134
Refuge Administration – Sandy Point NWR, Green Cay NWR, Buck Island NWR ........ 135
Funding and Personnel ............................................................................................................ 136
Partnership and Volunteer Opportunities ................................................................................. 137
Step-down Management Plans ................................................................................................ 137
Monitoring and Adaptive Management ..................................................................................... 138
Plan Review and Revision........................................................................................................ 138
Table of Contents iii
SECTION B. ENVIRONMENTAL ASSESSMENT
I. BACKGROUND ............................................................................................................................. 139
Introduction ............................................................................................................................... 139
Purpose and Need for Action ................................................................................................... 139
Decision Framework ................................................................................................................. 140
Planning Study Area ................................................................................................................. 140
Authority, Legal Compliance, and Compatibility ....................................................................... 140
Compatibility .................................................................................................................... 140
Public Involvement and the Planning Process ......................................................................... 141
II. AFFECTED ENVIRONMENT ....................................................................................................... 143
III. DESCRIPTION OF ALTERNATIVES .......................................................................................... 145
Formulation of Alternatives ....................................................................................................... 145
Description of Alternatives ........................................................................................................ 145
Sandy Point National Wildlife Refuge, St. Croix .............................................................. 145
Green Cay National Wildlife Refuge, St. Croix ................................................................ 160
Buck Island National Wildlife Refuge, St. Thomas .......................................................... 161
Features Common to All Alternatives ....................................................................................... 162
Sandy Point National Wildlife Refuge, St. Croix .............................................................. 162
Green Cay National Wildlife Refuge, St. Croix ................................................................ 165
Buck Island National Wildlife Refuge, St. Thomas .......................................................... 165
Alternatives Considered but Eliminated from Further Analysis ................................................ 166
Sandy Point National Wildlife Refuge, St. Croix .............................................................. 166
Green Cay National Wildlife Refuge, St. Croix ................................................................ 166
Buck Island National Wildlife Refuge, St. Thomas .......................................................... 166
IV. ENVIRONMENTAL CONSEQUENCES ...................................................................................... 167
Overview .................................................................................................................................. 167
Effects Common to All Alternatives .......................................................................................... 167
Environmental Justice ..................................................................................................... 167
Climate Change .............................................................................................................. 167
Other Management ......................................................................................................... 168
Land Acquisition .............................................................................................................. 168
Cultural Resources .......................................................................................................... 168
Refuge Revenue-Sharing ................................................................................................ 169
Other Effects ................................................................................................................... 169
Summary of Effects by Alternative ........................................................................................... 169
Sandy Point National Wildlife Refuge, St. Croix .............................................................. 169
Green Cay National Wildlife Refuge, St. Croix ................................................................ 174
Buck Island National Wildlife Refuge, St. Thomas .......................................................... 182
Unavoidable Impacts and Mitigation Measures ........................................................................ 185
Water Quality from Soil Disturbance and Use of Herbicides ........................................... 185
Wildlife Disturbance ........................................................................................................ 186
Vegetation Disturbance ................................................................................................... 186
User Group Conflicts ....................................................................................................... 186
Effects on Adjacent Landowners ..................................................................................... 186
Land Ownership and Site Development .......................................................................... 186
Cumulative Impacts .................................................................................................................. 187
iv Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
Direct and Indirect Effects or Impacts ...................................................................................... 187
Short-term Uses versus Long-term Productivity ....................................................................... 188
V. CONSULTATION AND COORDINATION .................................................................................... 189
Overview ................................................................................................................................. 189
Core CCP Planning Team ........................................................................................................ 190
Biological Review Team ........................................................................................................... 190
Visitor Services Review Team .................................................................................................. 191
SECTION C. APPENDICES
APPENDIX A. GLOSSARY .............................................................................................................. 193
APPENDIX B. REFERENCES AND LITERATURE CITATIONS ..................................................... 203
APPENDIX C. RELEVANT LEGAL MANDATES AND EXECUTIVE ORDERS ............................... 211
APPENDIX D. PUBLIC INVOLVEMENT .......................................................................................... 225
Summary of Public Scoping Comments ................................................................................... 225
Sandy Point National Wildlife Refuge, St. Croix ............................................................. 225
Green Cay National Wildlife Refuge, St. Croix ............................................................... 228
Buck Island National Wildlife Refuge, St. Thomas .......................................................... 230
APPENDIX E. APPROPRIATE USE DETERMINATIONS ............................................................... 233
APPENDIX F. COMPATIBILITY DETERMINATIONS ...................................................................... 243
Compatibility Determinations, Sandy Point National Wildlife Refuge, St. Croix ....................... 243
Compatibility Determinations, Green Cay National Wildlife Refuge, St. Croix ......................... 253
Compatibility Determinations, Buck Island National Wildlife Refuge, St. Thomas ................... 262
Approval of Compatibility Determinations ................................................................................ 273
APPENDIX G. INTRA-SERVICE SECTION 7 BIOLOGICAL EVALUATION ................................... 275
APPENDIX H. WILDERNESS REVIEW ........................................................................................... 283
APPENDIX I. REFUGE BIOTA ......................................................................................................... 287
Buck Island National Wildlife Refuge ....................................................................................... 287
Green Cay National Wildlife Refuge ......................................................................................... 290
Sandy Point National Wildlife Refuge ....................................................................................... 292
APPENDIX J. BUDGET REQUESTS ............................................................................................... 295
Refuge Operating Needs System (RONS) ............................................................................... 295
Maintenance Management System Needs .............................................................................. 295
APPENDIX K. LIST OF PREPARERS AND CONTRIBUTORS ....................................................... 297
Table of Contents v
LIST OF FIGURES
Figure 1. Location of the Caribbean Islands National Wildlife Refuge Complex,
highlighting the Sandy Point, Green Cay and Buck Island Refuges. ................................... 10
Figure 2. U.S. Virgin Islands and Sandy Point, Green Cay, and Buck Island Refuges. ..................... 11
Figure 3. Aerial image and boundary of Sandy Point National Wildlife Refuge. ................................. 12
Figure 4. Aerial image and boundary of Green Cay National Wildlife Refuge. ................................... 14
Figure 5. Aerial image and boundary of Buck Island National Wildlife Refuge. .................................. 15
Figure 6. Soils of Sandy Point National Wildlife Refuge. .................................................................... 25
Figure 7. Soils of Green Cay National Wildlife Refuge. ...................................................................... 27
Figure 8. Soils of Buck Island National Wildlife Refuge. ..................................................................... 30
Figure 9. Principal habitats of Sandy Point National Wildlife Refuge. ................................................. 35
Figure 10. Distribution of leatherback turtle nests at Sandy Point National Wildlife Refuge, 2006. .... 47
Figure 11. Annual number of leatherback females at Sandy Point Refuge, 1982-2007. .................... 48
Figure 12. Hatchling production of leatherback turtles at Sandy Point Refuge. .................................. 48
Figure 13. Leatherback hatchling nest success at Sandy Point NWR, 1982-2007. ............................ 50
LIST OF TABLES
Table 1. Eight elements of the Comprehensive Conservation Plan for the U.S. Virgin Islands. ......... 17
Table 2. Monthly climate summary in the vicinity of Sandy Point NWR. ............................................. 21
Table 3. Monthly climate summary in the vicinity of Green Cay NWR. ............................................... 21
Table 4. Monthly climate summary in the vicinity of Buck Island NWR. ............................................. 22
Table 5. Nesting activity data for green and hawksbill turtles at Sandy Point NWR, 2005. ................ 50
Table 6. St. Croix ground lizard surveys at Green Cay, 2007. ............................................................ 56
Table 7. St. Croix ground lizard surveys at Green Cay, 2003-2004. .................................................. 57
Table 8. Key demographic and socioeconomic data for the U.S. Virgin Islands................................. 63
Table 9. Population growth in the U.S. Virgin Islands, 1901-2000. ..................................................... 65
Table 10. Occupation, industry and class of worker statistics for the U.S. Virgin Islands, 2000. ........ 66
Table 11. Summary of new projects. ................................................................................................ 136
Table 12. Step-down management plans ......................................................................................... 138
Table 13. Comparison of alternatives by management issues for Sandy Point NWR. ..................... 152
Table 14. Comparison of alternatives by management issues for Green Cay NWR. ....................... 163
Table 15. Comparison of alternatives by management issues for Buck Island NWR. ...................... 164
Table 16. Summary of environmental effects by alternative, Sandy Point NWR. ............................. 175
Table 17. Summary of environmental effects by alternative, Green Cay NWR. ............................... 181
Table 18. Summary of environmental effects by alternative, Buck Island NWR. .............................. 184
vi Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
Draft Comprehensive Conservation Plan 1
SECTION A. DRAFT COMPREHENSIVE CONSERVATION PLAN
I. Background
INTRODUCTION
The U.S. Fish and Wildlife Service (Service) has developed this Draft Comprehensive Conservation Plan
to provide a foundation for the management and use of Sandy Point, Green Cay, and Buck Island
national wildlife refuges, which are located in the U.S. Virgin Islands. The plan is intended to serve as a
working guide for the three refuges’ management programs and actions over the next 15 years. Fish and
wildlife conservation will receive the first priority in refuge management. Wildlife-dependent recreational
activities will be allowed and encouraged as long as they are compatible with—and do not detract from—
the missions of the refuges or the purposes for which they were established.
The plan was prepared in compliance with the National Wildlife Refuge System Improvement Act of
1997 and Part 602 (National Wildlife Refuge System Planning) of the Fish and Wildlife Service
Manual. The plan also meets the requirements of the National Environmental Policy Act of 1969
(NEPA) through the inclusion of an Environmental Assessment (Section B), which describes the
alternatives that are being considered and their potential effects on the environment.
A planning team developed a range of different alternatives that best meet the goals and objectives of
the three individual refuges and that could be implemented within the 15-year planning period. In
developing the plan, the planning team has incorporated the input of federal and island territory
agencies, nongovernmental organizations, local citizens, and the general public. This public
involvement and the planning process itself are described in Chapter III, Plan Development.
This plan represents the Service’s proposed alternatives for each of the three refuges and is being
put forward after considering a number of other alternatives for each refuge, which are described in
the Environmental Assessment (Section B). The plan is being made available to federal and island
territory agencies, conservation partners, and the general public for review and comment. All
comments from this public review will be considered in the development of the final plan.
PURPOSE AND NEED FOR THE PLAN
The purpose of the plan is to develop a proposed action that best achieves the purposes of the three
refuges; attains the vision and goals developed for each refuge; contributes to the mission of the
National Wildlife Refuge System; 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 clear statements of the management direction for each refuge;
􀁹􇤠 provide refuge neighbors, visitors, and government officials with an understanding of the
Service’s management actions on and around each refuge;
􀁹􇤠 ensure that the Service’s 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 each refuge’s budget requests for operations,
maintenance, and capital improvement needs.
2 Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
U.S. FISH AND WILDLIFE SERVICE
The U.S. Fish and Wildlife Service traces its roots to 1871 with 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 under the Department of Commerce and Labor in 1903.
The Service also traces its roots to 1886 through 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’s Bureau of Fisheries was combined with the Department of
Agriculture’s 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, protecting, and enhancing fish and wildlife and their
habitats for the continuing benefit of the American people through federal programs relating to
migratory birds, endangered species, interjurisdictional fish and marine mammals, and inland sport
fisheries (142 DM 1.1).
As part of its mission, the Service manages more than 540 national wildlife refuges covering over 95
million acres. These areas comprise the National Wildlife Refuge System, the world’s largest
collection of lands set aside specifically for fish and wildlife. The majority of these lands, 77 million
acres, are in Alaska. The remaining acres are spread across the other 49 states and several United
States territories. In addition to refuges, the Service manages thousands of small wetlands, national
fish hatcheries, 64 fishery resource offices, and 78 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, and helps
foreign governments with their conservation efforts. It also oversees the Federal Aid program that
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. Actions were
initiated in 1997 to comply with the direction of this new legislation, including an effort to complete
comprehensive conservation plans for all refuges. These plans, which are completed with full public
Draft Comprehensive Conservation Plan 3
involvement, help guide the future management of refuges by establishing natural resources and
recreation/education programs. Consistent with this Act, approved plans 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 the requirement of developing a comprehensive conservation plan for each unit of the
Refuge System, and fully involve the public in the preparation of these plans;
􀁹􇤠 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
􀁹􇤠 retain the authority of refuge managers to determine compatible public uses.
The following are just a few examples of the Service’s 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 overhunting, competition with cattle, and natural disasters decimated the
once-abundant herds. The drought conditions of the Dust Bowl during the 1030s severely depleted
breeding populations of ducks and geese. Refuges established during the Depression focused on
waterfowl production areas, such as those that protected 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.
National Wildlife Refuges connect visitors to their natural resource heritage and provide them with an
understanding and appreciation of fish and wildlife ecology to help them understand their role in the
environment. Wildlife-dependent recreation on refuges also generates economic benefits to local
communities. According to the report, Banking on Nature 2006: the Economic Benefits to Local
Communities of National Wildlife Refuge Visitation, approximately 34.8 million people visited national
wildlife refuges in fiscal year 2006, generating almost $1.7 billion in total economic activity and
creating almost 27,000 private sector jobs producing about $542.8 million in employment income
(Carver and Caudill 2007). Additionally, recreational spending on refuges generated nearly $185.3
million in tax revenue at the local, county, state, and federal levels (Carver and Caudill 2007). As the
number of visitors grows, significant economic benefits are realized by local communities. In 2006,
nearly 71 million people, 16 years and older, fished, hunted, or observed wildlife, spending $45.7
billion and generating $122.6 billion (Leonard 2008).
Volunteers continue to be a major contributor to the success of the Refuge System. In 2002,
volunteers contributed more than 1.5 million hours on refuges nationwide, a service valued at
more than $22 million.
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.
4 Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
The National Wildlife Refuge System Improvement Act of 1997 stipulates that comprehensive
conservation plans 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 plans.
All lands of the Refuge System will be managed in accordance with an approved comprehensive
conservation plan that will guide management decisions and set forth strategies for achieving refuge
unit purposes. The plan will be consistent with sound resource management principles, practices,
and legal mandates, including the Service’s 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. The treaties and laws relevant to the administration of the National Wildlife
Refuge System and management of Sandy Point, Green Cay, and Buck Island national wildlife
refuges are summarized in Appendix C.
These 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. They also provide a framework for
cooperation between the Sandy Point, Green Cay, and Buck Island national wildlife refuges and other
partners, such as the Virgin Islands Department of Planning and Natural Resources, the National
Park Service, the St. Croix Environmental Association, The Nature Conservancy, the West Indies
Marine Animal Research and Conservation Service, private landowners, and community members.
National Wildlife Refuge System lands are closed to public use unless specifically and legally
opened. No refuge use may be allowed unless it is determined to be 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 the mandates of the National Wildlife Refuge
System Improvement Act, including those that:
􀁹􇤠 contribute to ecosystem goals, as well as the purposes and goals of the refuge;
􀁹�� conserve, manage, and restore fish, wildlife, and plant resources and their habitats;
􀁹􇤠 monitor the trends of fish, wildlife, and plants;
􀁹􇤠 manage and ensure appropriate wildlife-dependent visitor uses as those uses which benefit
the conservation of fish and wildlife resources and which contribute to the enjoyment of the
public; and
􀁹􇤠 ensure that visitor activities are compatible with refuge purposes.
The Act further identifies six priority wildlife-dependent recreational uses: hunting, fishing,
wildlife observation, wildlife photography, and environmental education and interpretation. As
priority public uses of the Refuge System, they receive priority consideration over other public
uses in planning and management.
Draft Comprehensive Conservation Plan 5
Biological Integrity, Diversity, and Environmental Health Policy
The National Wildlife Refuge System 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. This policy is an additional directive for
refuge managers to follow while achieving the purposes of each refuge and the mission of the
System. It provides for the consideration and protection of the broad spectrum of fish, wildlife, and
habitat resources found on the refuges and their associated ecosystems. When evaluating the
appropriate management direction for refuges, refuge managers will use sound professional
judgment to determine their refuges’ contribution to biological integrity, diversity, and environmental
health at multiple landscape scales. Sound professional judgment incorporates field experience;
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
Because many issues affecting the protection and management of natural resources transcend
geopolitical boundaries, multiple partnerships have been developed among government and private
entities to address the environmental problems affecting regions. A large amount of conservation
and protection information 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 the declining trends of natural, physical, social, and economic
environments. The conservation plans and initiatives described below, along with issues, problems,
and trends, were reviewed and integrated where appropriate into this Draft Comprehensive
Conservation Plan.
North American Bird Conservation Initiative. Started in 1999, the North American Bird
Conservation Initiative 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
is an international action plan to conserve migratory birds throughout the continent. Its goal is to
return waterfowl populations to their 1970s levels by conserving wetland and upland habitats.
Canada and the United States signed the plan in 1986 in reaction to critically low numbers of
waterfowl. Mexico joined in 1994, making it a truly continental effort. The plan is a partnership of
federal, provincial, state, and municipal governments, nongovernmental 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. The plan’s 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.
Partners in Flight Bird Conservation Plan. Growing concern about declines in many land bird
species not covered by existing conservation initiatives, primarily nongame species, led to the
launching of Partners in Flight in 1990. Partners in Flight is an international, cooperative effort of
government agencies, philanthropies, professional organizations, conservation groups, industry,
academics, and private individuals. Its initial focus was on neotropical migratory birds—species that
breed in North America and winter in Central and South America—but its emphasis has now
6 Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
expanded to encompass most land birds and other species requiring terrestrial habitats. Partners in
Flight has a number of initiatives underway, including a North American Landbird Conservation Plan.
This plan is voluntary and nonregulatory, 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. Partners in Flight’s main premise is that the resources of public and private
entities in the Americas, both North and South, must be combined, coordinated, and increased if
success in conserving hemispheric bird populations is to be achieved (Partners in Flight, no date).
Partners in Flight has formed bird conservation plans by bird conservation regions that set
conservation priorities and habitat and population objectives. The U.S. Virgin Islands and Puerto
Rico are within the Southeast Working Group, which also includes states ranging from Texas in the
southwest to Maryland in the northeast (Partners in Flight, no date).
U.S. Shorebird Conservation Plan. The U.S. Shorebird Conservation Plan is a partnership effort
throughout the United States that works to ensure the protection and restoration of stable and self-sustaining
populations of shorebird species. The plan was developed by a wide range of agencies,
organizations, and shorebird experts for separate regions of the country. It 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.
Northern American Waterbird Conservation Plan. The North American Waterbird Conservation
Plan provides a framework for the conservation and management of 210 species of waterbirds in 29
nations. Threats to waterbird populations include destruction of inland and coastal wetlands; the
introduction of 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 this plan is the standardization of data collection efforts to
better recommend effective conservation measures.
RELATIONSHIP TO ISLAND TERRITORY WILDLIFE AGENCIES
A provision of the National Wildlife Refuge System Improvement Act of 1997, and subsequent agency
policy, is that the Service shall ensure timely and effective cooperation and collaboration with other
state or U.S. island territory fish and game agencies and tribal governments during the course of
acquiring and managing refuges. National wildlife refuges such as Sandy Point, Green Cay, and
Buck Island, as well as national parks such as Buck Island Reef National Monument and Virgin
Islands National Park, provide the foundation for wildlife conservation, and contribute to the overall
health and sustainability of fish and wildlife in the Territory of the United States Virgin Islands.
The U.S. Virgin Islands’ Department of Planning and Natural Resources (DPNR) was established in
1987, under Act 5265 of the Government Reorganization and Consolidation Act. Among other
responsibilities, the DPNR is charged with the administration and enforcement of all laws related to
the preservation and conservation of fish and wildlife, trees and vegetation, coastal zones, cultural
and historical resources, water resources, and air, water and oil pollution in the U.S. Virgin Islands.
The DPNR formulates long-range comprehensive and functional development plans for the human,
economic and physical resources of the territory (DPNR 2005a).
Draft Comprehensive Conservation Plan 7
The DPNR’s Division of Fish and Wildlife (DFW) is responsible for monitoring, assessing and
implementing public awareness and other activities that help to enhance and safeguard fish and
wildlife resources in the U.S. Virgin Islands. The DFW is the primary scientific advisor to the
Commissioner of DPNR on the condition and status of the territory’s wildlife and marine resources.
The Commissioner, in turn, advises the Governor of the U.S. Virgin Islands. Three bureaus comprise
the DFW: the Bureau of Fisheries, the Bureau of Wildlife, and the Bureau of Environmental
Education. Unique within DPNR, the Division of Fish and Wildlife is 100 percent federally funded by
the U.S. Department of the Interior’s Fish and Wildlife Service, Division of Federal Aid, and by the
U.S. Department of Commerce’s National Marine Fisheries Service (NMFS) and National Oceanic
and Atmospheric Administration (NOAA) (DPNR 2005).
The DFW’s participation and contribution throughout this planning process will provide for ongoing
opportunities and open dialogue to improve the ecological sustainability and recovery of fish and
wildlife populations in the Territory of the U.S. Virgin Islands. An essential part of comprehensive
conservation planning is the integration of common mission objectives, where appropriate.
8 Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
Draft Comprehensive Conservation Plan 9
II. Overview of the Refuges
INTRODUCTION
The three national wildlife refuges that are the subject of this Draft Comprehensive Conservation
Plan—Sandy Point, Green Cay, and Buck Island—are all located in the U.S. Virgin Islands, in the
eastern Caribbean Sea. They are administered by the Service as part of the Caribbean Islands
National Wildlife Refuge Complex, which includes the nine refuges shown in Figure 1.
Sandy Point National Wildlife Refuge is situated on the southwestern tip of St. Croix. Green Cay
National Wildlife Refuge is a 14-acre island located less than one-half mile offshore of the
northeastern side of St. Croix. Buck Island National Wildlife Refuge (which is often confused with
Buck Island Reef National Monument in St. Croix, administered by the National Park Service) is
situated about two miles south of St. Thomas (Figure 2). All three refuges constitute a subcomplex of
the Caribbean Islands National Wildlife Refuge Complex. They are all managed from an office at
Sandy Point National Wildlife Refuge, where the refuge staff (refuge manager and refuge biologist) is
based. At this time, the Green Cay and Buck Island refuges do not have onsite facilities.
HISTORY AND PURPOSES OF THE THREE REFUGES
Sandy Point National Wildlife Refuge, St. Croix, includes 383 acres without any inholdings (Figure
3). The refuge’s establishing purposes were “… to conserve (A) fish or wildlife which are listed as
endangered species or threatened species … or (B) plants.” The refuge was established in 1984
when 340 acres were purchased from the West Indies Investment Company. The land was
purchased specifically to protect nesting habitat of endangered leatherback sea turtles. An additional
43 acres have been acquired since that time to protect the Aklis archeological site and a stand of the
endangered Vahl’s boxwood tree.
Sandy Point National Wildlife Refuge provides critical nesting habitat for three species of federally
threatened and endangered sea turtles. The leatherback sea turtle and the hawksbill sea turtle are
federally listed as endangered, and the green sea turtle is federally listed as a threatened. These
three sea turtle species are also protected under Territory of the U.S. Virgin Islands regulations.
The federally endangered leatherback sea turtle is the largest sea turtle species in the world and the
largest nesting population within United States jurisdiction occurs at Sandy Point NWR. The
leatherback sea turtle recovery program began on Sandy Point with tagging efforts in 1977, and has
since developed into one of the most unique, long-term sea turtle research and recovery efforts in the
world. The program is the result of cooperative efforts between partnering agencies, researchers,
nongovernmental organizations, and volunteers. This work resulted in the establishment of the
refuge, a leatherback sea turtle population that has grown consistently over the last 27 years, and a
scientific database that has documented this population growth. This unique database is critical for
leatherback sea turtle population recovery world-wide.
Structurally, Sandy Point National Wildlife Refuge is a peninsula supported by stable geologic
formations. Although the shoreline represents one of the longest sandy beaches in the U.S. Virgin
Islands, it is highly dynamic and constantly eroding and re-depositing sand throughout the year. As a
result, the refuge beach represents optimal nest habitat for sea turtles and a highly desirable site for
public beach recreation.
10 Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
Figure 1. Location of the Caribbean Islands National Wildlife Refuge Complex, highlighting the Sandy Point, Green Cay and
Buck Island Refuges.
Draft Comprehensive Conservation Plan 11
Figure 2. U.S. Virgin Islands and Sandy Point, Green Cay, and Buck Island Refuges.
12 Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
Figure 3. Aerial image and boundary of Sandy Point National Wildlife Refuge.
Draft Comprehensive Conservation Plan 13
The principal management objectives for Sandy Point National Wildlife Refuge are to:
􀁹􇤠 provide habitat and protection for threatened and endangered species, with particular
emphasis on the leatherback and other species of sea turtles;
􀁹􇤠 foster a sense of public commitment and understanding for sea turtles and the need for
protection by providing opportunities for environmental education, interpretation, and
compatible wildlife-oriented recreation;
􀁹􇤠 support the Service’s commitment to implement and carry out sea turtle recovery plans; and
􀁹􇤠 protect and restore habitat for a natural diversity of plant and wildlife species.
Green Cay National Wildlife Refuge, St. Croix, was established in 1977 to protect the endangered
St. Croix ground lizard. The refuge consists of the entire 14-acre island of Green Cay (Figure 4). The
refuge’s establishing purpose was to conserve “fish or wildlife which are listed as endangered species
or threatened species.” The refuge extends only to sea level and does not include any of the
submerged marine habitat, including coral reefs which surround the island. Outcrops of lava, tuffs
and breccias are prominent terrestrial geological features. Archeological conch shell middens
(discarded conch shells) once occurred on the shoreline. Estimated to contain as many as thirty-three
thousand shells, these middens demonstrated 1,000 years of human use or occupancy, dating
back to as early as 1020 A.D.
This island refuge provides critical habitat for the largest remaining natural population of the federally
endangered St. Croix ground lizard. Its extirpation from the main island of St. Croix, just several
hundred yards away, is generally attributed to the modification and loss of shoreline habitat resulting
from human activities, and the introduction of predators, such as rats, cats, and dogs. The
introduction of the exotic Indian mongoose likely completed the elimination of the species from St.
Croix. As a result, this species is one of the rarest reptiles in the world and is unique to St. Croix
island ecosystems.
The principal management objective for Green Cay National Wildlife Refuge is to maintain the
existing population of St. Croix ground lizards at its maximum possible level in order to ensure the
viability of the island population and to provide lizards for reintroduction to other suitable sites in its
former range. Essential to achieving this objective is the restoration of the island’s natural
ecosystem, which has been badly degraded by introduced rats, deforestation, and the establishment
of exotic, nonnative plants. Elimination of rats is critical because rats have reduced native forest
cover by eating tree shoots and buds, and eating tree seedlings. Rat elimination is also problematic
because of the proximity of the island to the main island of St. Croix; the rats can easily be
reintroduced to Green Cay by negligent human activities or natural processes (storms, rafting on
floating debris, etc.). Reforestation of the island will also provide needed habitat for a variety of bird
species, especially colonial nesting birds like brown pelicans, and native doves and pigeons.
Buck Island National Wildlife Refuge, St. Thomas, was established in 1969. The refuge consists of
the entire 45-acre island (Figure 5). The refuge extends to sea level and does not include submerged
or marine habitat.
14 Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
Figure 4. Aerial image and boundary of Green Cay National Wildlife Refuge.
Draft Comprehensive Conservation Plan 15
Figure 5. Aerial image and boundary of Buck Island National Wildlife Refuge.
16 Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
Initially, the Service obtained approximately 35 acres of the island from the U.S. Navy in 1969. An
additional 9 acres was obtained from the U.S. Coast Guard in 1981. The final 0.92-acre parcel which
included the historic iron lighthouse was obtained from the U.S. Coast Guard in 2004. The purpose
for establishment of the refuge was its “… particular value in carrying out the national migratory bird
management program.”
The offshore islands around St. Thomas support a number of critical seabird and migratory bird
roosting, breeding, and nesting sites. Some of these offshore islands have been impacted by varying
degrees of development and habitat alteration, making the remaining islands even more critical for
use by migratory birds. Although Buck Island’s natural plant and wildlife communities have been
severely impacted by human activity, the island has major potential for habitat restoration,
enhancement and support of migratory bird populations, and maintenance of existing wildlife
populations, both endemic and migratory. The refuge is home to two rare reptiles endemic to the
“Puerto Rican bank” (geological area containing Puerto Rico, Culebra, St. Thomas, and the British
Virgin Islands): the Antillean skink and the Puerto Rican racer. The island currently provides nesting
habitat for the magnificent frigatebird, the red-billed tropicbird, and laughing gulls.
The principal management objective for the refuge is to support migratory bird populations through
habitat restoration and management.
While Buck Island’s rocky coastline and dry thorn-scrub vegetation offer less recreation potential, the
surrounding waters contain coral reefs and a shipwreck that attracts large numbers of snorkelers,
divers, and boaters from nearby Charlotte Amalie, St. Thomas. The U.S. Coast Guard maintains a
lighthouse on the refuge, adjacent to an historic lighthouse that dates to the Danish colonial period.
SPECIAL DESIGNATIONS
None of the three refuges contain special designations such as wilderness areas, oil and gas
activities, wild and scenic rivers, research natural areas or demonstration areas. The nearshore
waters and beach areas of Sandy Point NWR have federal critical-habitat designation.
ECOSYSTEM CONTEXT
The three refuges are located in the Caribbean Ecosystem, as delineated by the U.S. Fish and
Wildlife Service’s national ecosystem mapping project. This ecosystem is home to 78 threatened and
endangered species (29 animals and 49 plants), including species of birds, reptiles, and amphibians,
as well as unique and diverse habitats ranging from coral reefs, sandy beaches, and mangrove
forests to limestone hills and forested mountains. The Caribbean Ecosystem contains nine national
wildlife refuges, distributed from near Haiti, across Puerto Rico, to the U.S. Virgin Islands (U.S. Fish
and Wildlife Service [USFWS], no date-a). This ecosystem ranges from tropical to subtropical in
temperature and climate, borders the Atlantic Ocean in some areas, and is surrounded by the
Caribbean Sea in other areas.
Since the end of the Second World War, human population has increased dramatically on almost
every island in the Caribbean region. Existing cities, towns, and communities have dramatically
increased in size and new communities have been established. Commercial and subsistence
agriculture and fishing, and urban/residential expansion have heavily impacted native flora and fauna,
fisheries sustainability, and reduced habitat for wildlife. Much of the economy of the Caribbean
region is dependant on tourism, which is directly linked to the natural beauty of Caribbean islands and
the quality of its marine ecosystems. Dramatic increases in both resident populations and visitors
have resulted in overfishing, poaching, introduction of nonnative and invasive species, industrial
Draft Comprehensive Conservation Plan 17
pollution, deforestation, and terrestrial, aquatic, and marine habitat degradation and destruction.
While these human impacts have been accumulating for centuries, negative ecological trends have
all accelerated as a result of the demands explosive human growth has placed on the environment.
Within the U.S. Virgin Islands (USVI), the demands for space and land created by a rapidly growing
human population of over 100,000 have resulted in extensive loss and degradation of natural
ecosystems, especially on densely populated St. Thomas (Seaman 1974). Sprawling residential
communities and commercial centers have displaced or fragmented much of the native forest.
Hotels, condominiums, and marinas have been constructed on coastal wetlands, and marine
recreational activities have damaged fragile mangrove swamps, coral reefs, and seagrass beds.
Development and human activities have led to increased pollution and the introduction of nonnative
and invasive plant and animal pests. Furthermore, the natural ecosystems are subject to the effects
of short- and long-term wet and dry climatic cycles, and to periodic disturbances from hurricanes,
including the recent hurricanes Hugo in 1989 and Marilyn in 1995 (DFW 2005).
REGIONAL CONSERVATION PLANS AND INITIATIVES
In 2005, the DPNR’s Division of Fish and Wildlife published A Comprehensive Wildlife Conservation
Strategy for the U.S. Virgin Islands (DFW 2005). The Conservation Strategy represents a compilation
of two separate planning efforts. The first is a strategic management plan for the USVI with funds
from a U.S. Fish and Wildlife Service FW16 grant. The strategic plan focuses on species or species
groups that are harvested commercially or recreationally, that is, to animals with “fur” or “feathers” in
the USVI. The second planning effort is for a comprehensive wildlife conservation plan with funds
from a USFWS T2 grant under the State Wildlife Grant program. This plan focuses on all non-harvested
species or species groups that comprise the wildlife and marine resources of the USVI.
The Service provided guidelines for writing the plan in the form of eight specific elements (Table 1).
Table 1. Eight elements of the Comprehensive Conservation Plan for the U.S. Virgin Islands.
Element 1: Inventory Distribution and abundance of wildlife species
Element 2: Condition Location and condition of habitats that are vital for conserving important
wildlife species
Element 3: Threats Identification of threats to wildlife species and habitats, and prioritization
of research for conservation actions
Element 4: Actions Prescriptions and priorities for conserving wildlife species and habitats
Element 5: Monitoring Plans for assessing effectiveness of conservation actions
Element 6: Review Evaluation of the CWCP at intervals not to exceed ten years
Element 7:
Coordination
Involvement of federal, state, and local agencies in conservation plans
and actions
Element 8: Public
Participation
Involvement of the general public in the development of the
conservation plan and resulting actions. This involvement is required by
law and is essential for the successful implementation of the CWCP
18 Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
The Conservation Strategy is divided into four parts: (1) Introduction, which provides background
information; (2) Habitats of the USVI, focusing on major ecosystems; (3) Wildlife Species of the USVI,
focusing on taxonomic groups and high priority species; and (4) Implementation of the Strategy,
addressing the relationships between the DFW and its stakeholders. Within parts 2 and 3, each
chapter (a) describes the status of each conservation target, identifies its major threats, and
summarizes past efforts at research, management, and conservation; (b) identifies the species of
concern; (c) outlines the DFW’s strategies for implementing research, management, and conservation
of the target; (d) briefly describes current and future needs for assessing conservation status and
effectiveness of implemented actions for conservation; and (e) provides pertinent references of
previous studies in the USVI. Part 4 of the Conservation Strategy outlines the status and issues for
each subject and the priorities for action (DFW 2005).
Each of the eight required elements is addressed within the Conservation Strategy. Distribution and
abundance of species of wildlife (Element 1) are treated in parts 2 and 3 (Habitats and Wildlife Species),
and the locations and conditions of the key habitats for these species (Element 2) are treated in part 2
(Habitats). For each species or species group and habitat, the species of concern are listed and the
conservation threats and action priorities and research required to overcome these threats (Element 3)
are addressed. Part 1 presents an overall territory-wide prioritization of conservation effort needed to
improve the conditions of wildlife territory-wide (Element 4). Part 4 outlines the monitoring effort required
to ensure long-term sustainability of wildlife populations, and to ensure the effectiveness of conservation
efforts; it also discusses adaptive management strategies (Element 5), and lists specific monitoring needs
for each species group and ecosystem in parts 2 and 3. Part 1 also outlines the procedure for the review
of the plan into the future (Element 6). Coordination with other agencies required to develop and
implement the plan is addressed in part 1 and part 4 (Element 7). Lastly, public participation (Element 8)
is described in parts 1 and 4 (DFW 2005).
ECOLOGICAL THREATS AND PROBLEMS
The inherent beauty of the lands and waters of the Caribbean belies the serious conservation biology
challenges facing this region. In the U.S. Virgin Islands, the threats to wildlife include habitat loss,
degradation and alteration, increasing levels of pollution, burgeoning populations of nonnative
species of plants and animals, increasing human presence and recreational use of marine, shoreline,
and terrestrial areas, and a general lack of awareness and understanding of wildlife issues. These
threats are increasing in magnitude over time (DFW 2005).
The rising demand for land on which to build housing, roads, and infrastructure to support a growing
population of full and part-time residents and develop resorts to accommodate a growing number of
tourists generates ever-increasing pressures on wildlife habitat and biodiversity. One-third of densely
populated St. Thomas is classified as “developed,” and this statistic does not even consider the level
of fragmentation or the integrity of the remaining “undeveloped” habitat (DFW 2005).
Existing personnel resources of resource and land management agencies in the Virgin Islands are
inadequate to provide for effective enforcement. Environmental officers are in short supply, and they
often lack sufficient training to identify environmental violations and take appropriate actions. In addition
to the scarcity of funding and staff resources for enforcement, cultural issues within the territory make
enforcement difficult. Distrust of governmental and other authority figures mean violations go unreported
or witnesses are not willing to testify. Traditional practices that have long been illegal, such as sea turtle
harvesting and bird egg theft, are still occurring. These issues can be addressed only by a combination of
judicious enforcement and community outreach and education (DFW 2005).
Draft Comprehensive Conservation Plan 19
The incidental, accidental, or deliberate introduction of nonnative species of animals and plants to island
ecosystems often leads to dramatic adverse impacts on native populations of flora and fauna, not only in
the Virgin Islands, but around the world. Exotics that are already present on the U.S. Virgin Islands,
especially terrestrial mammals such as the small Indian mongoose (Herpestes javanicus), rats (Rattus
rattus and R. norvegicus), feral domestic dogs and cats, and grazing livestock have had devastating
effects on reptile and bird populations as well as plant communities. The mongoose is believed to have
been the primary cause in the extirpation (elimination) of the St. Croix ground lizard from the main island
of St. Croix. New introductions of plants and animals are occurring too frequently.
Plants sometimes brought in for landscaping purposes may spread rapidly across the islands and
outcompete native vegetation. Examples of the most common invasives include tan-tan (Leucaena
leucocephala) and guinea grass (Panicum maximum). Animals imported as pets and livestock can carry
diseases, and can escape and establish feral populations. Some species, such as frogs and lizards
transported with produce or landscape vegetation, have been inadvertently introduced (DFW 2005).
Disposal of wastes and refuse is a major problem on heavily populated islands. Accumulation of
trash and industrial waste, combined with point and nonpoint source water pollution from cars leaking
engine oil or radiator fluid, road spills, excessive exhaust emissions, runoff during heavy rains
containing agricultural substances (pesticides, fertilizers, and sediments), and inadequate sewer
systems that frequently fail ensure a continual influx of contaminants into the ecosystem. On the U.S.
Virgin Islands, household waste is collected at dumpsters located along main roads. Feral animals
congregate around the dumpsters, introducing public health issues and increasing threats to native
species through predation or competition for localized resources. The lack of adequate waste
containment, overuse of plastic shopping bags, limited recycling opportunities (nonferrous metals),
and the general culture of littering all ensure that trash finds its way into the sea to create hazards for
sea turtles and other marine organisms. Infractions of dumping regulations and industrial and
transportation pollution are rarely enforced. Noise pollution from aircraft, seaplanes, motorboats, and
motor vehicles is also a serious nuisance, especially on overcrowded St. Thomas (DFW 2005).
The Service’s conservation efforts in the Caribbean respond to these various threats (USFWS 2002).
The Service lists its greatest priorities (not ranked) in the region as:
􀁹􇤠 Species of Concern and Listed Species
􀁹􇤠 Migratory Birds
􀁹􇤠 Bats
􀁹􇤠 Subtropical Dry Forest Conservation/Enhancement/Restoration
􀁹􇤠 Wetland and Mangrove Restoration
􀁹􇤠 Coral Reefs
􀁹􇤠 Invertebrates
􀁹􇤠 Invasive Exotic Species
􀁹􇤠 Law Enforcement
􀁹􇤠 Fire Management
􀁹􇤠 Contaminants
The Caribbean Islands National Wildlife Refuge Complex protects several highly endangered
ecosystems, including (1) subtropical dry forest, (2) coral reefs, and (3) seagrass beds and adjacent
beaches used by nesting and foraging threatened and endangered sea turtles. The Complex also
protects important habitats for migrating shorebirds, nesting seabirds, and an increasing number of
sites with emergent wetlands and mangroves (USFWS 2002).
20 Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
The Complex conserves wildlife and ecosystems found nowhere else in the United States. Many of
the component species are endemic, such as the St. Croix ground lizard which exists on St. Croix
and no where else on Earth. Many migratory birds depend on habitat found within the Complex,
including a large number of Fish and Wildlife Service Birds of Conservation Concern. Particularly
notable are (1) species found nowhere else in the United States or elsewhere on Earth, (2) species
spending part of the year in the neotropics (i.e., neotropical migrants), and (3) species that have
unique breeding site requirements making them extremely vulnerable to decline, such as colonially
nesting seabirds, waterfowl, marshbirds, and shorebirds (USFWS 2002).
In addition to the above-listed threats and problems that confront Virgin Islands wildlife, is the
overarching threat of global climate change resulting from worldwide anthropogenic emissions of
greenhouse gases. Global warming is not only heating the atmosphere, it is warming the world’s
oceans. Warmer waters, in turn, cause the ocean to expand, raising sea levels along coastlines and
exposing coastal habitats and human development to flooding, especially during storms and
hurricanes. In the future, hurricanes are likely to become more intense, with higher peak wind
speeds and heavier precipitation (Intergovernmental Panel on Climate Change [IPCC] 2007).
Elevated sea levels will have disastrous consequences for wildlife dependent on beach and coastal
habitat. Because of topographic structure, many beach habitats will not “move to higher elevation” as
sea level increases, they will disappear.
Furthermore, increasing temperatures are harming the ecological integrity and health of marine
ecosystems, spreading disease and causing massive coral bleaching in places such as Virgin Islands
National Park and Buck Island Reef National Monument. Today, up to 90 percent of the corals in the
Virgin Islands are dead or dying due to a host of factors, including widespread coral bleaching, in
which stressed coral polyps expel from their tissues the colorful symbiotic algae they need to survive
(National Wildlife Federation [NWF] 2007). In addition to the complex marine ecosystems provided
by healthy coral reef systems, coral reefs also furnish physical protection to shoreline areas and
entire islands from catastrophic waves generated by hurricanes and tsunamis.
Oceanographers have recently begun to express grave concern about the vast potential implications of
another result of increasing atmospheric carbon dioxide levels: acidification of the surface layers of the
ocean due to higher concentrations of carbonic acid, formed when the ocean absorbs carbon dioxide.
While research into this phenomenon and its possible ramifications is still in its infancy, there is convincing
evidence to suggest that such acidification will affect the process of calcification, whereby marine
organisms like corals and molluscs construct shells and plates from calcium carbonate. Tropical and
subtropical corals are anticipated to be among the worst affected, with ominous implications for the
stability and longevity of the coral reefs they build and the diverse, productive, and colorful ecological
communities that depend on them (Kleypas et al. 2006; Royal Society 2005).
PHYSICAL RESOURCES
CLIMATE
All three national wildlife refuges in the USVI experience a semi-arid, subtropical climate. Due to the
maritime influence, there is relatively little variation in daily and seasonal temperatures. Average daily
maximum temperatures are in the mid- to upper 80 degrees Fahrenheit (F), while average daily
minimum temperatures range from the lower to upper seventies. Winds are predominantly trade
winds blowing from the east.
Draft Comprehensive Conservation Plan 21
Annual rainfall ranges from 35-45 inches annually (USFWS 1999a). While the Virgin Islands do not have
a defined rainy season, there are month to month variations in precipitation. In descending order, the
rainiest months in the Virgin Islands are November, October, September, August and May (Anon. 2007a).
Each of the USVI refuges is exposed to hurricanes and tropical storms seasonally, with September
and October being the peak of the annually recurring hurricane season.
Sandy Point National Wildlife Refuge
Table 2 presents average maximum and minimum temperatures by month and average monthly
precipitation (all of which falls as rainfall) from a Federal Aviation Administration (FAA) weather
station at St. Croix’s airport several miles east of Sandy Point NWR. The average annual maximum
monthly temperature is about 87° F, and the average annual minimum monthly temperature is 75° F.
Annual rainfall is approximately 40 inches.
Table 2. Monthly climate summary in the vicinity of Sandy Point NWR.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Average Max.
Temperature (F) 84.2 84.3 85.0 85.9 87.0 88.3 89.0 89.4 89.1 88.5 86.7 85.0 86.9
Average Min.
Temperature (F) 72.1 72.1 72.4 74.1 76.1 78.1 78.3 78.0 77.1 75.9 74.5 73.2 75.1
Average Total
Precipitation (in.) 2.06 1.86 1.72 2.08 3.47 2.08 2.89 3.66 5.15 5.35 6.51 3.39 40.22
Source: Southeast Regional Climate Center, 2007a
Period of Record: 1/1/1972 to 12/31/2003
Green Cay National Wildlife Refuge
Table 3 presents average maximum and minimum temperatures by month and average monthly
precipitation (all of which falls as rainfall) from a weather station in Christiansted several miles west of
Green Cay NWR. The average annual maximum monthly temperature is about 86° F, and the
average annual minimum monthly temperature is 74° F. Annual rainfall is approximately 41 inches.
Table 3. Monthly climate summary in the vicinity of Green Cay NWR.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Average Max. Temperature
(F) 83.0 83.1 83.7 84.7 86.2 87.0 86.9 87.3 87.7 87.6 85.7 83.7 85.5
Average Min. Temperature
(F) 71.1 70.9 71.9 73.4 75.1 76.9 76.5 76.2 75.5 75.0 74.0 72.4 74.1
Average Total Precipitation
(in.) 2.02 1.49 1.68 2.50 4.18 2.68 3.00 3.67 5.23 5.27 6.23 3.20 41.17
Source: Southeast Regional Climate Center, 2007b
Period of Record: 1/1/1972 to 11/30/2005
22 Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
Buck Island National Wildlife Refuge
Table 4 presents average maximum and minimum temperatures by month and average monthly
precipitation (all of which falls as rainfall) from a weather station in Charlotte Amalie on St. Thomas,
several miles north of Buck Island NWR. The average annual maximum monthly temperature is
about 88° F, and the average annual minimum monthly temperature is 75° F. Annual rainfall is
approximately 39 inches.
Table 4. Monthly climate summary in the vicinity of Buck Island NWR.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Average Max. Temperature
(F) 85.2 85.2 85.9 86.8 87.7 89.3 90.1 90.4 89.8 89.0 87.3 85.8 87.7
Average Min. Temperature
(F) 72.2 72.0 72.5 74.1 76.2 77.6 77.9 77.8 77.4 76.5 75.0 73.2 75.2
Average Total Precipitation
(in.) 1.97 1.49 1.54 2.71 3.33 2.55 2.56 3.54 5.37 5.57 5.61 2.93 39.19
Source: Southeast Regional Climate Center, 2007c
Period of Record: 1/12/1972 to 12/31/2005
GEOLOGY AND TOPOGRAPHY
Although the Caribbean islands form an island arc or chain, they were not formed at the same time in
the geologic past. Those of the Greater Antilles—the islands of Cuba, Jamaica, and Hispaniola (Haiti
and the Dominican Republic)—are older than those of the Lesser Antilles, including the Virgin
Islands. The Greater Antilles are made up of continental rock, while the Lesser Antilles consist of
mostly young volcanic or coral islands. The Lesser Antilles more or less coincide with the outer edge
of the Caribbean (tectonic) Plate, and many of the islands were formed by subduction, as one or
more other plates slipped under the Caribbean Plate (Anon. 2007b).
Sandy Point National Wildlife Refuge, St. Croix
The refuge is comprised of a peninsula that projects west and south from the southwestern portion of the
island and includes adjacent interior coastal areas and salt ponds. In terms of geological structure, Sandy
Point NWR is unique in St. Croix, which is geologically unique within the U.S. Virgin Islands.
The island of St. Croix consists of the tip of a submarine platform separated from Puerto Rico and the
remaining Virgin Islands by the nearly three-mile deep Virgin Islands Basin and Anegada Gap or trough.
The upper or surface portion of the platform dates to the Late Cretaceous, and consists of predominantly
sedimentary rocks derived from deep-marine volcanic origins (Panamerican Consultants 1997). As a
result, St. Croix is the only island within the US Virgin Islands that does not border the Atlantic Ocean; it is
the only major island that is completely surrounded by the Caribbean Sea.
These predominantly sedimentary rocks are termed the Caledonia Formation, which contains
mudstones, sandstones, and limestones, among other rocks. This formation occurs on both the
eastern and western ends of St. Croix. The Judith Fancy Formation, dating to the very end of the
Cretaceous Period, overlies the Caledonia Formation. The Judith Fancy Formation consists of a thick
Draft Comprehensive Conservation Plan 23
sequence of tuffaceous rock and is located in the western and central-eastern portion of the island.
Overlying these two formations within the refuge are Quaternary alluvial and beach deposits, which
form a major part of the geologic structure of the refuge (Panamerican Consultants 1997).
The eastern boundary of the refuge has the highest elevation within the refuge and contains exposed
limestone formations and occasional exposed volcanic mudstone and sandstone. Westward of these
exposed formations is the West End Salt Pond. Its southern two-thirds are within the refuge
boundary. The western shoreline of the West End Salt Pond is only a few feet above sea level and
contains mangrove habitat. Westward and southward from the salt pond, refuge habitat is almost
exclusively low-elevation sandy soil supporting dry coastal thorn-scrub habitat, extending to the
refuge beaches that border the Caribbean Sea.
This is what makes Sandy Point geologically unique within St. Croix. It contains the longest beach in
the Virgin Islands because the beach is essentially an enormous sandy peninsula that wraps around
the West End Salt Pond (and the western end of St. Croix). No other site like it exists on the island
and its geologic formation is unique in the region. The peninsula originated from sand accumulation
caused by oscillating north and south shore currents. Although the underlying geologic formation of
sandstones and limestone is quite stable, beach areas are highly dynamic. Sand deposition and
erosion occur continuously, and the width of the beach varies significantly throughout the year. Not
only do these dynamic processes create extensive beach areas, but they create and maintain beach
areas that are optimal as nesting sites for leatherback, green, and hawksbill sea turtles. No other sea
turtle nesting sites having the same dynamic conditions exist in St. Croix or anywhere else in the US
Virgin Islands. Maps dating back more than three centuries to 1667 show Sandy Point essentially the
same as it is today – a flat area with a maximum elevation of less than ten feet (USFWS 1999a).
Green Cay National Wildlife Refuge, St. Croix
Green Cay is a small, 14-acre, uninhabited island about 1,650 feet in length (northeast to southwest)
and approximately 500 feet in width at its widest point. The island is about 1,200 feet north of
Chenay Bay beach on the main island of St. Croix.
The southern third of the island is the highest point at 63 feet above sea level. Structurally, the island
is composed primarily of igneous (volcanic) rock. The shoreline perimeter ranges from vertical to
relatively steep, consisting of exposed volcanic mudstone, solidified magma, and exposed horizontal
strata that has been uplifted and folded to almost vertical positions. Other portions of the shoreline
are relatively narrow and range from steep to almost horizontal. At the surface these areas are
composed of a mixture of loose sand and alluvial soil mixed with shells, pieces of coral, and “talus”
(loose volcanic mudstone and igneous rock that has washed down to the shoreline).
Within the exposed strata are rocks consisting of layered hornblendite intrusives and roof pendants of
steeply dipping quartose hornfels of the Cretaceous Caledonia Formation (Weiss and Gladfelter
1978). Some of these “quartzite” layers are almost vertical and can be seen from miles away.
The island’s slopes are covered locally with stony terra rosa, a reddish tropical laterite soil that has a
high clay and iron content and relatively little organic material. Stones on the surface are angular
chunks of closely fractured bedrock. Cliffs rim much of the island’s perimeter, but colluvial slopes
have been cut back by the surf locally, perhaps as a result of the Holocene sea level rise (Weiss and
Gladfelter 1978). Severe wave-cutting of the island’s perimeter, especially along the western
shoreline, has continued into recent times during hurricane and strong storm episodes.
24 Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
A small sandy beach is located at the extreme northern end of the island. Large, exposed offshore
rocks lie just north of this beach and are exposed to heavy wave action throughout the year. The
island has a continuous coral reef along its eastern perimeter which protects a small beach on its
southeastern shoreline. This beach is more properly a sandbar which appears and disappears
throughout the year due to wave action and oscillating currents.
Buck Island National Wildlife Refuge, St. Thomas
Buck Island has high, rocky cliffs, sheltered coves, and a very rocky shoreline. The geologic history
of Buck Island is very complex. Like Green Cay, Buck Island and neighboring Capella Island are
composed primarily of igneous (volcanic) rocks. The main rock is a form of diorite or granodiorite.
This particular diorite more closely resembles a salt and pepper granite than diorite proper. All diorite
exposures on the island are heavily weathered. The diorite weathers to a very fine granular gravel
and eventually to soil (Anon. 1974).
A more siliceous form of diorite is found in a dike cutting across the granodiorite on the northeastern end
of Buck Island. This rock contains considerable amounts of the mineral orthoclase feldspar, which is
unusual in the USVI. It looks similar to conglomerate, characterized by large crystals of quartz, mica, and
the alteration products of hornblende in a thick matrix of the mineral oligoclase. Instead of the whole rock
weathering simultaneously, the diorite’s large crystals weather first (Anon., 1974).
Other dikes on Buck Island are composed of the igneous rock diabase, which is dark green, with dark
silicates completely changed to the metamorphic minerals epidote and chlorite.
SOILS
Sandy Point National Wildlife Refuge, St. Croix
The soils of the Sandy Point Refuge are depicted in Figure 6. The most common soil type is Jaucas
Sand, which forms most of the peninsula. The Natural Resources Conservation Service (NRCS) lists
the following soil properties and qualities for Jaucas Sand (NRCS 1998):
􀁹􇤠 Drainage class: Excessively drained
􀁹􇤠 Permeability: Very rapid
􀁹􇤠 Available water capacity: Low
􀁹􇤠 Organic matter content: Low
􀁹􇤠 Natural fertility: Low
􀁹􇤠 Hazard of erosion: Slight
􀁹􇤠 Seasonal high water table: More than 6 feet deep
􀁹􇤠 Depth to bedrock: More than 60 inches
􀁹􇤠 Root zone: More than 60 inches
􀁹􇤠 Shrink-swell potential: Low
􀁹􇤠 Salinity: Moderately saline
􀁹􇤠 Flooding: Rare
􀁹􇤠 Stoniness: Non-stony
Draft Comprehensive Conservation Plan 25
Figure 6. Soils of Sandy Point National Wildlife Refuge.
26 Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
While the NRCS rates Jaucas Sand as “unsuited to most recreational uses” because of the severe
limitations imposed by flooding, the sandy subsoil, and excess salt, and as “poorly suited to use as
wildlife habitat,” it notes at the same time that this unit is in fact used mainly for recreational uses and
as wildlife habitat (NRCS 1998). The refuge’s beach sand is calcareous (calcium carbonate-based
sand). Because this sand is not siliceous (not a silica-based sand), its grains are flattened, not round,
and do not compact tightly as silica-based sands usually do. As a result, the beach sand at the
refuge remains loose and noncompacted, eroding and redepositing more readily than other sands.
Hesselberg Clay predominates on the northeastern part of the refuge. The Hesselberg series
consists of shallow, well-drained soils on marine terraces, usually above a limestone base. These
soils formed in alkaline, clayey sediments. Slopes range from 0 to 12 percent. The NRCS lists the
following soil properties and qualities for Hesselberg Clay (NRCS 1998):
􀁹􇤠 Drainage class: Well drained
􀁹􇤠 Permeability: Slow
􀁹􇤠 Available water capacity: Low
􀁹􇤠 Organic matter content: Moderate to high
􀁹􇤠 Natural fertility: Moderate to high
􀁹􇤠 Hazard of erosion: Moderate
􀁹􇤠 Seasonal high water table: More than 6 feet deep
􀁹􇤠 Depth to bedrock: 10 to 20 inches
􀁹􇤠 Root zone: 10 to 20 inches
􀁹􇤠 Shrink-swell potential: High
􀁹􇤠 Salinity: Non-saline
􀁹􇤠 Flooding: None
􀁹􇤠 Stoniness: Non-stony
The NRCS rates this soil as “poorly suited for recreational uses” because of the depth to a cemented
pan and the clayey subsoil. The NRCS also rates it as poorly suited for use as wildlife habitat
because of a cemented pan, the low available water capacity, the depth to water, and the
droughtiness of the soil (NRCS 1998). In fact, the soil substrate in the northern and eastern area of
the refuge supports one of the last remaining portions of relatively undisturbed dry, coastal thorn-scrub
habitat on St. Croix, including one of the largest stands of the federally-listed endangered
Vahl’s boxwood tree.
Green Cay National Wildlife Refuge, St. Croix
The soils of the Green Cay Refuge are depicted in Figure 7. Only three soil types have been
identified on this small island: the Southgate-Rock Outcrop Complex, 40 to 60% Slopes; the Victory-
Southgate Complex; and the Victory-Southgate Complex, 20 to 40% Slopes.
Southgate-Rock Outcrop Complex, 40 to 60% Slopes – The settings of this soil unit in the Virgin
Islands landscapes are summits and side slopes of volcanic hills and mountains. The NRCS lists the
following properties and qualities for this soil unit (NRCS 1998):
􀁹􇤠 Drainage class: Well drained
􀁹􇤠 Permeability: Moderate
􀁹􇤠 Available water capacity: Very low
􀁹􇤠 Organic matter content: Low to moderate
Draft Comprehensive Conservation Plan 27
Figure 7. Soils of Green Cay National Wildlife Refuge.
28 Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
􀁹􇤠 Natural fertility: Moderate
􀁹􇤠 Hazard of erosion: Severe
􀁹􇤠 Seasonal high water table: More than 6 feet deep
􀁹􇤠 Depth to bedrock: 10 to 20 inches
􀁹􇤠 Root zone: 10 to 20 inches
􀁹􇤠 Shrink-swell potential: Low
􀁹􇤠 Salinity: Non-saline
􀁹􇤠 Flooding: None
􀁹􇤠 Stoniness: Extremely stony
The NRCS rates this soil type as unsuited for recreation uses because of limitations imposed by
slope and depth to bedrock and as poorly suited for use as wildlife habitat because of bedrock,
droughtiness, and depth to water (NRCS 1998). However, of the sites where this soil unit occurs on
the refuge, vegetation cover exists and provides essential habitat for St. Croix ground lizards as well
as other species of birds and reptiles.
The two remaining units mapped on Green Cay—the Victory-Southgate Complex, and the Victory-
Southgate Complex, 20 to 40% Slopes—are related to each other, representing a combination of the
Victory Series and the Southgate Series. A “series” consists of soils within a soils family that have
horizons similar in color, texture, structure, reaction, consistence, mineral and chemical composition,
and arrangement in the profile. Like the Southgate-Rock Outcrop Complex just described, the
Victory-Southgate Complex is also found on summits and side slopes of volcanic hills and mountains
in the Virgin Islands. The NRCS lists the following properties and qualities for these two soil units
(NRCS 1998):
􀁹􇤠 Drainage class: Well drained
􀁹􇤠 Permeability: Moderate
􀁹􇤠 Available water capacity: Low to very low
􀁹􇤠 Organic matter content: Low to high
􀁹􇤠 Natural fertility: Low to moderate
􀁹􇤠 Hazard of erosion: Severe
􀁹􇤠 Seasonal high water table: More than 6 feet deep
􀁹􇤠 Depth to bedrock: 10 to 40 inches
􀁹􇤠 Root zone: 10 to 40 inches
􀁹􇤠 Shrink-swell potential: Low
􀁹􇤠 Salinity: Non-saline
􀁹􇤠 Flooding: None
􀁹􇤠 Stoniness: Very stony
The NRCS rates this map unit as unsuited for recreational uses because of limitations imposed by the
slope, depth to bedrock, and small stones on the surface. According to the NRCS, the Victory-
Southgate Complex is also poorly suited to use as wildlife habitat because of management concerns
related to the depth to bedrock, the shallow rooting depth, depth to water, and droughtiness of the soil
(NRCS 1998). However, this soil unit supported an almost continuous forest canopy across most of
the island prior to the arrival of Europeans. Unfortunately, this dry-forest canopy developed over
many centuries, if not millennia, and was very susceptible to disturbance by human activities. The
characteristics of this soil make habitat restoration problematic because the tree species involved can
take centuries to mature and maintain themselves.
Draft Comprehensive Conservation Plan 29
Buck Island National Wildlife Refuge, St. Thomas
The soils of the Buck Island Refuge are depicted in Figure 8. The island’s soils are dominated by
three units of the Southgate-Rock Outcrop Complex: 12 to 20% slopes, 20 to 40% slopes, and 40 to
60% slopes. These units are differentiated only by the severity of slope. The soil properties,
limitations and uses are described in the section above under Green Cay National Wildlife Refuge.
Another series occurs on the beaches on the north and east of the island: Redhook Extremely Stony
Sand, 0 to 5% Slopes. The landform position of this unit is on coastal beaches that are composed of
calcareous sand. The NRCS lists the following properties and qualities for this soil unit (NRCS 1998):
􀁹􇤠 Drainage class: Excessively drained
􀁹􇤠 Permeability: Very rapid
􀁹􇤠 Available water capacity: Low
􀁹􇤠 Organic matter content: Low
􀁹􇤠 Natural fertility: Low
􀁹􇤠 Hazard of erosion: Slight
􀁹􇤠 Seasonal high water table: More than 6 feet deep
􀁹􇤠 Depth to bedrock: More than 60 inches
􀁹􇤠 Root zone: More than 60 inches
􀁹􇤠 Shrink-swell potential: Low
􀁹􇤠 Salinity: Moderately saline
􀁹􇤠 Flooding: Rare
􀁹􇤠 Stoniness: Rubbly
The NRCS notes that while this map unit is in fact used mainly for recreational purposes and as
wildlife habitat, it is “unsuited” for the former and “poorly suited” for the latter due to a number of
limitations and management concerns. However, these ratings themselves are somewhat flawed by
narrow definitions as to what constitutes valuable wildlife habitat and recreational potential.
Additionally, the very nature of these soil units is what ultimately determines vegetation cover and
habitat characteristics. Both native plant species and native animal species have developed and are
adapted to the limitations and opportunities imposed by the habitat conditions that result from these
soil unit characteristics.
HYDROLOGY, WATER QUALITY AND QUANTITY
Due to their small sizes—and in the case of Sandy Point NWR, its minimal relief—there are no
permanent stream courses on any of the USVI refuges. Indeed, the only surface water flow would
occur during and immediately after storm events. The very low to low water capacity of the soils
described in the previous section, coupled with high evapotranspiration rates (averaging 63 inches
per year in the case of Green Cay), result in a water deficit throughout much of the year. Due to the
drying effect of winds, available moisture varies sharply between the windward and leeward sides of
the refuges, especially Green Cay and Buck Island.
All three refuges contain extensive beachfront areas influenced by the Caribbean’s modest tides,
wave action, and high salinity. Plant and animal life in this zone are adapted to harsh and variable
physical conditions.
30 Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
Figure 8. Soils of Buck Island National Wildlife Refuge.
Draft Comprehensive Conservation Plan 31
Three-quarters of the West End Salt Pond is located in the Sandy Point Refuge. It is the largest salt
pond in the Virgin Islands and is a shallow, hyper-saline, brackish lagoon ringed by mangroves
without a surface outlet to the sea. The Salt Pond comprises roughly one-quarter of the refuge’s
area. Four other smaller salt ponds are located within the refuge’s boundaries.
AIR QUALITY
The air quality in the U.S. Virgin Islands is regulated by the Division of Environmental Protection (DEP), a
unit of the Department of Planning and Natural Resources (DEP 2006). The DEP provides regulatory
oversight and has authority to implement and enforce air pollution and air quality requirements in the
USVI. Under the auspices of its Air Pollution Control Program (APC), the DEP is responsible for both air
quality and compliance monitoring, as well as for issuing permits. Air quality monitoring consists of
collecting weekly particulate matter samples from five monitoring stations in the territory. On St. Croix, the
local oil refinery, Hovensa—the largest in the Western Hemisphere and located approximately eight miles
east of the Sandy Point Refuge—conducts sulfur dioxide monitoring at its petrochemical facility.
Compliance monitoring consists of annual or more frequent inspections of regulated facilities to determine
compliance. Citizens’ complaints also assist the DEP in identifying sources that are out of compliance
with local and or federal laws. The DEP processes applications and issues permits to construct, install
and operate air pollution emission sources (DEP 2006).
Under the Federal Clean Air Act, as amended in 1970, 1977, and 1990, the United States
Environmental Protection Agency (EPA) established the National Ambient Air Quality Standards
(NAAQS) to protect human health with an adequate margin of safety by setting maximum ambient air
concentrations for six “criteria” pollutants (de Nevers 2000). The six criteria pollutants are carbon
monoxide (CO), ozone (O3), nitrogen oxides (NOx), sulfur dioxide (SO2), lead (Pb) and particulate
matter (PM). PM is regulated both as PM10 (particulate matter less than or equal to 10 microns in
diameter) and PM2.5 (particulate matter less than or equal to 2.5 microns in diameter, about 1/30th the
width of a human hair).
All areas of the U.S. Virgin Islands meet the EPA's new, more stringent, health-based fine particle
standard. Fine particles (PM 2.5) have been shown to cause premature mortality, aggravate asthma
and other unhealthy respiratory conditions and contribute to cardiovascular problems such as heart
attack and arrhythmia (EPA 2004).
The National Park Service has continuously monitored ozone at Virgin Islands National Park on the
island of St. John since 1998. The data indicate no exceedances of the 1-hr human health-based
primary NAAQS, or any calculated exceedances of the new 8-hr primary NAAQS (National Park
Service [NPS] 2005).
Dust from the Sahara Desert frequently contributes to visibility impairment at Virgin Islands National
Park and the USVI in general. During these Saharan dust episodes, visibility impairment can be
significant. While the issue has not been studied to date, some scientists have also expressed
concern that there may also be nutrient or disease impacts associated with dust deposition in the
marine environment (NPS 2005). Additionally, volcanic eruptions from Monserrat Island deposit
volcanic ash in the Virgin Islands, also causing health and environmental hazards.
As part of the nationwide Toxic Release Inventory (TRI) under the auspices of the EPA, more than
600 chemicals and chemical categories of toxic releases in the Virgin Islands from a number of
industries are currently tracked. The EPA reports that from 2000 to 2001, total releases of toxic
substances increased from approximately 670,000 pounds to over 1,000,000 pounds. The increase
was due to higher amounts of carbonyl sulfide, carbon disulfide and nitrate compounds emissions
32 Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
reported by Hovensa, based on more extensive sampling at its facility. Hovensa promised the EPA
that it would revise past TRI reports and use specialty catalysts to reduce their future emissions (EPA
2003). While a number of Hovensa’s neighbors rate the oil refinery’s environmental record highly,
others claim its emissions have caused ailments ranging from skin rashes to burning eyes to nausea
(Relly 1999). The Hovensa oil refinery is located roughly equidistant between Sandy Point NWR and
Green Cay NWR on St. Croix, about 10 miles east of the former and 10 miles southwest of the latter.
BIOLOGICAL RESOURCES
HABITAT
The 2005 Comprehensive Conservation Strategy for the U.S. Virgin Islands, prepared by the DPNR’s
Division of Fish and Wildlife, identifies and describes several notable habitat types and subtypes that
occur on the U.S. Virgin Islands and within the three Virgin Islands national wildlife refuges.
Beaches and Rocky Shorelines – This edge habitat is where marine and terrestrial ecosystems
meet and overlap. The 235-mile USVI coastline (including 50 cays) consists of both beaches and
rocky shorelines; it comprises a large percentage of the total island area. Sandy beaches comprise
50 miles or over 20 percent of the total shoreline (Dammann and Nellis 1992).
There are three types of beaches in the USVI: sand, gravel, and coralline. Sandy beaches are a
mixture of several materials, including coral particles, shell and urchin fragments, and algal plates.
Gravel beaches are made of minerals or rocks that erode from cliffs and are carried to the shore
during torrential rainfalls. Coralline rubble beaches are formed by fragments of coral skeleton broken
by storm action and deposited by currents, tide, and waves.
Beaches furnish habitat for numerous invertebrates, which in turn serve as food for vertebrates,
especially shorebirds. They also provide a substrate for nesting sea turtles. Shoreline species must
be drought, heat, and salt-tolerant.
Wetlands – Wetlands are areas sufficiently inundated or saturated by water to support a prevalence
of “hydrophytic” vegetation, that is, plants adapted for life in saturated soils. Wetlands are vital
habitats for wildlife and fisheries, providing food, shelter from predators, protective nurseries, and
filters of sediments and pollutants. Wetlands occur throughout the major islands and cays of the
USVI, and have been grouped into five categories: salt ponds, salt flats, mangrove wetlands, mixed
swamp, and freshwater ponds. Two of the categories—salt ponds and mangroves—occur at Sandy
Point NWR. The two island refuges—Green Cay and Buck Island—are too small, well-drained, and
hilly to contain substantial wetlands.
Salt Ponds. Salt ponds are the dominant type of wetland found in the USVI. These are small bodies of
saltwater that form into intertidal basins. Originally open to the sea as bays or inlets, they become
isolated from the sea over time as storm-deposited materials form a berm. The resulting ponds may
maintain an influx of salt water either through tidal seepage or periodic breaching of the berm by the sea
during storm surges. Water salinity, oxygen content, and temperature are highly variable and dependent
on rainfall and evaporation (Dammann and Nellis 1992). Salt ponds support invertebrates that are
important prey for shorebirds and other waterbirds. These ponds also act as catchment basins for runoff,
debris, and pollutants, thus protecting coral and seagrass beds in the marine environment.
Mangrove Wetlands. These are periodically flooded forests that grow in sheltered, tidal areas
throughout the tropics. Mangroves are trees that have converged in their adaptations for colonizing
quiet, shallow coastal habitats with a broad range of salinities and relatively anoxic (low oxygen) soils.
Draft Comprehensive Conservation Plan 33
In the USVI, there are four species of trees in four distinct genera and three taxonomic families.
Mangrove forest is dominated by the red mangrove (Rhizophora mangle), and to a lesser extent by
black mangrove (Avicennia germinans), white mangrove (Laguncularia recemosa) and buttonwood
(Conocarpus erectus), forming a closed canopy. Mangrove woodland is similar but with a more open
canopy and dominated by mangrove species other than the red mangrove. Mangrove wetlands are
nursery grounds for reef fishes and invertebrates, and mangrove roots trap sediment washed from
upland areas. Trapped soil eventually causes the shoreline to grow seaward over time, as terrestrial
vegetation fills in the land created behind the mangrove stand.
Shrublands and Grasslands – Shrublands and grasslands are widespread in the USVI, especially
on St. Croix. They occur in dry lowland areas and some moist upland areas, and are maintained by
grazing, cutting, or fire. Shrublands and grasslands provide an important resource for wildlife,
although they have lower wildlife species diversity than forest because of the lower diversity of plant
species and simpler vegetative structure.
Shrublands. Shrublands occur in dry locations at low elevations on all islands, including cays such as
Green Cay and Buck Island. Because vegetative growth is limited by thin, infertile soils, strong winds,
and minimal moisture, shrubland vegetation is relatively short, typically ranging from 2-15 feet in
height. Nevertheless, shrubland vegetation is often dense and sometimes nearly impenetrable to
humans. Bushy, multiple-stemmed shrubs that are often thorny and have interlocking branches
typically dominate the vegetation of this habitat. Cacti and other succulents may be interspersed
among the shrubs. The subtypes of USVI shrublands include gallery shrubland, thicket/scrub, mixed
dry shrubland, coastal hedge, and sclerophyllous (thick, hard, leathery foliage) evergreen shrubland.
Grasslands. Grasslands occur in areas with very low rainfall or subjected to frequent disturbance by
agriculture, grazing, fire, or mowing. In the Virgin Islands, most grasslands are anthropogenic, that is,
a result of human activity, and represent an early stage of succession. Grassland-dominated
communities with less than 10 percent cover from shrubs and trees are referred to as pasture, which
is maintained by grazing or fire. When such communities are covered 10-25 percent by shrubs and
trees, they are referred to as pasture mixed scrub; this usually results from succession when grazing
is discontinued and fire excluded. Mixed dry grassland is 25-50 percent covered by shrubs and trees,
and usually results from selective grazing by livestock that shun spiny or poisonous plants. Coastal
grassland occurs naturally where extreme conditions from wind, salt spray, and low moisture combine
to preclude the survival and growth of woody plants, thus enabling the growth of grasses adapted to
such harsh environments.
Forests – In the USVI as elsewhere, forests are an important habitat not just for wildlife but for
human consumption and recreation. The diversity of plant species and the complex structure of
forests furnish a wealth of ecological niches for forest-dependent animal species to find food, seek
shelter, avoid predation, and reproduce. The dominant native forest ecosystems of the USVI include
subtropical dry forests and, to a smaller extent, subtropical moist forests. Forested habitats are highly
variable. Although several sub-types of forest habitat are recognizable, they grade readily into one
another and are generally difficult to delineate without being arbitrary.
Dry Forest. Dry forest occurs at lower elevations, typically below 1,000 feet, where annual rainfall
ranges from 33-40 inches. The height of climax vegetation may reach 50-70 feet, but is shorter on
steep slopes, in areas subjected to strong winds, and where exposed to heavy salt spray. Usually
only two canopy layers are formed. The foliage tends to be deciduous in more humid areas and
sclerophyllous in drier areas.
34 Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
Moist Forest. Moist forest refers to seasonal evergreen forests with predominantly broad-leafed trees
forming a canopy ranging in height from 30-100 feet. Seventy percent or more species in a moist
forest are evergreen and there is typically some loss of foliage during the 2-4 month dry season.
Rainfall generally exceeds 50 inches per year.
Woodlands. The woodlands that occur throughout the USVI are relatively open, characterized
by separated crowns and a reduced canopy cover of about 25-60 percent. The canopy height
varies from about 25-70 feet, depending upon human modifications, the effects of hurricanes,
and soil moisture. Most woodlands in the USVI are “anthropogenic in origin” and often contain
naturalized, nonnative plants.
Except for a relatively small amount of dry forest and woodland at Sandy Point NWR, forested habitat
is not well represented in any of the USVI national wildlife refuges.
Cays – More than 50 small, mostly uninhabited islands, collectively referred to as “cays,” are
sprinkled throughout the USVI and comprise about three percent of the territory’s total area. Because
of their relative inaccessibility and the scarcity of predators on many of them, the cays provide
sanctuary for a variety of wildlife species and are especially important for colonial nesting seabirds.
The varied vegetation formations on cays include subtropical dry forest, shrublands, and grasslands.
When present, salt ponds and their associated mangroves provide habitat for a variety of
invertebrates, shorebirds, and indigenous waterbirds. Sparsely vegetated geological formations
(such as cliffs, rock outcrops, and beaches) provide habitat for nesting seabirds and other wildlife.
In comparison with the major islands in the USVI, the terrestrial fauna of the cays is generally
depauperate (poor in species diversity). Amphibians and many landbirds are usually absent because
of the absence of subtropical forest habitat, reduced habitat complexity, and the small size of cays.
However, seabird colonies may thrive on cays because of their very isolation and small size.
Nonnative species, in particular rats, are an ever-present, long-term menace to the flora and fauna of
cays. Rats both eat native vegetation and prey upon wildlife, including the eggs and nestlings of
seabirds, and seabirds have abandoned some of these islands. Green Cay NWR and Buck Island
NWR are both cays.
Sandy Point National Wildlife Refuge, St. Croix
Figure 9 shows the different habitats or vegetative communities present at Sandy Point National
Wildlife Refuge. Most of the refuge—about two-thirds—is covered with dense shrubland, described
generally in the previous section. Approximately one-quarter of the refuge consists of the West End
Salt Pond, the light green area designated as wetland in Figure 9. This brackish, shallow, low-oxygen
salt pond is heavily used by water-dependent birds (such as seabirds, shorebirds, wading
birds and waterfowl) and is rimmed by mangroves.
The remaining 10-15 percent of the refuge is divided among the dry forest, herbaceous, sparse
vegetation, and woodland categories and includes four other small salt ponds. Approximately
225 species of plants in 64 distinct taxonomic families have been identified at Sandy Point
NWR (Anon. no date).
Draft Comprehensive Conservation Plan 35
Figure 9. Principal habitats of Sandy Point National Wildlife Refuge.
36 Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
Green Cay National Wildlife Refuge, St. Croix
The first formal inventory of the flora of Green Cay was conducted nearly a quarter of a century ago
(Woodbury and Vivaldi 1982). At this time, the flora consisted of over 60 species, most being native.
There were approximately 12 tree, 20 shrub, nine vine, and 18 herbaceous species. Species
diversity is low at about 4.5 species per acre. Recent visits have revealed an additional five species
(only one native) bringing the total species count to 65 (Lombard, pers com).
Natural forest is poorly developed except for a closed mesic forest on the southwestern part of the
cay. Other less densely forested areas are found throughout the southern half of the cay. The
dominant tree species are Cordia rickseckeri, Tabebuia heterophylla, and Hippomane mancinella.
Most of the cay is covered by shrubs, mainly Eupatorium sinuatum, Oplonia spinosa, Lantana
involucrata, and Clerodendrum aculeatum. The northern half of the cay primarily has a shrub-grassland
association. It is characterized by impenetrable, almost mono-specific shrub stands up to
two meters tall, together with wind swept grasslands. Herbaceous plants are scattered throughout
the cay. There are three main exotic species that appear to be increasing in abundance, Tecoma
stans, Andropogen pertusus, and Panicum maximum.
Four plant communities were identified and two of these were subdivided into plant associations. Soil
types and wind exposure appeared to the most significant factors determining vegetation types. The
four plant communities are:
Beach Vegetation. This was restricted to the Jaucas sand on the southern end of the island. With
the exception of a few buttonwood (Conocarpus erectus), beach vegetation was composed of shrubs,
vines, and herbs less than three feet high.
Mesic Cordia Forest. This had the most developed trees on the island, and was restricted to the
southwestern part, where a deeper, reddish soil (Victory Southgate Complex) had accumulated and
the high point to the east protected the forest from the easterly trade winds. Available moisture
appeared to be greater than for the rest of the island. The humid forest soil contrasted sharply with
the dry and shallow soils found elsewhere. Cordia rickseckeri was the dominant species, reaching
heights of about 25 feet and a diameter at breast height (dbh) of three feet. The second most
common species in this forest was the vine Cissus sicyoides, found hanging from most of the trees.
Rivina humilis was the most common shrub. The western part of this small forest and the cliff area,
where a brown pelican roosting and nesting area is located, was somewhat drier than the rest of the
forest and had two cacti species.
Dry Woodland. This community occupied the rest of the southern half of Green Cay. This was a
more open habitat with large, dense patches of the grass Andropogen pertusus. A second invasive
grass species, guinea grass (Panicum maximum) has arrived in more recent years (Lombard, pers
com) and is found in patches around the northern part of the southern hill. Here trees attained a
maximum height of little more than 10-12 feet. On the basis of tree cover and species composition,
two associations were delineated within this community, an open Cordia woodland and a closed
Hippomane-Tabebuia woodland. The former was found mostly in the shallow, rocky soils of the
Southgate-Rock land complex on the more exposed areas of Green Cay. The dominant trees were
Cordia alba and Cordia rickseckeri. The exotic species Tecoma stans formed almost pure stands on
the eastern, windward slopes and is rapidly expanding its range in all directions. The latter
(Hippomane-Tabebuia woodland) had much more tree cover, shade, some litter accumulation, and
close spacing of trees. For the most part, this association was found on deeper soils to the north and
northeast of the southern hill.
Draft Comprehensive Conservation Plan 37
Shrub-Grassland Association. This plant community occupied the northern half of the island. It was
characterized by impenetrable, almost mono-specific shrub stands up to 6-7 feet tall, along with wind-swept
grasslands. A small woodland was also present. This community was subdivided into five distinct
associations, three of which were shrub associations, one woodland, and one grassland. The five
associations were (1) an almost pure stand of Lantana involucrata, (2) an almost pure stand of Oplonia
spinosa, (3) a narrow band of Eupatorium sinuatum, (4) a small Tabeubia-Hippomane-Cereus woodland,
and (5) a large grassland associations with small shrubs and sedges occupying much of the northern part
of the island. Today, Tecoma stans has begun to expand into this northern range of the cay.
Buck Island National Wildlife Refuge, St. Thomas
Starting in 2001, intermittent site visits and wildlife surveys have been conducted at Buck Island.
Buck Island consists of a mixture of shrubland and grassland, with small interspersed patches of
poorly developed subtropical dry forest or woodland. A total of 100 species of vegetation have been
documented, of these only 40 have been positively identified. Approximately 65 percent of the island
consists of shrubland habitat, thirty percent grassland, and the remaining five percent dry or
woodland forest. The VI-endangered wooly nipple cactus (Mammalaria nivosa) occurred in five
clumps of 10-20 individuals and six other lone individuals were also observed in 2001. On more
recent visits no individuals were observed.
The only formal survey of flora and habitats on the Buck Island Refuge took place more than 30 years
ago, several years after the refuge’s establishment in 1969 (Anon. 1974). It was conducted by a
team of students from the Hackley School in Tarrytown, New York, under the direction of four
university biologists and marine biologists.
The main kinds of plants identified on the leeward side of Buck Island were mimosa, sea grape, wild
thyme, frangipani, goat’s foot, thorny shrubs and bushes, lianas, cacti, and foxtail grass. Plant cover
was similar throughout the island – dense masses of thorny shrubs, choked with vines, interrupted by
stretches of tall golden foxtail grasses. Near the shore, sea grape and goats foot grew abundantly.
Moving inland, surveyors encountered wild thyme, lianas, frangipani, and herbs. Prickly pear and
barrel cacti were numerous. Vegetation was thickest on the northern side, where shrubs entangled
with vines were nearly impenetrable. Many plants had spines or thorns.
Due to the influence of wind and salt spray from waves, the flora of the windward side of Buck Island
differed significantly from the flora of the leeward side. Tall bushes, shrubs and grasses were replaced by
short grasses, bushes, herbs and barrel cacti. The dominant windward plants on and near the shoreline
were barrel cactus, sea grape, goats foot, and the legume Canavalia lineata. Away from the shore,
grasses were dominant, especially Sporobolus virginicus (marsh grass or crab grass).
WILDLIFE
Staffing constraints at the three refuges have precluded the conducting of wildlife inventories or the
preparing of checklists for the five major classes of vertebrates—birds, mammals, amphibians, reptiles
and fish. Management has necessarily emphasized threatened and endangered species at each refuge.
Thus, the discussion of wildlife overall must be in general terms, and is drawn primarily from the DFW’s
Comprehensive Wildlife Conservation Strategy for the U.S. Virgin Islands (DFW 2005).
Invertebrates
In terms of biodiversity, there are far more species of invertebrates (animals without backbones) than
any other fauna in the Virgin Islands. They include a wide variety of tropical snails, slugs, crabs,
38 Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
spiders, scorpions, centipedes, millipedes, and insects, as well as freshwater fauna such as snails,
crabs, crayfish, and a number of insect taxa. To date, the invertebrate fauna of the USVI are still
poorly inventoried, in spite of efforts begun as far back as the 1920s and 1930s. The fact that not a
single invertebrate species in the USVI is currently listed as endangered or threatened by the federal
and territorial governments is less a reflection of their actual status than a lack of knowledge
regarding that status.
A wide diversity of terrestrial crabs live in the USVI, and many of these occur on the three refuges,
especially Sandy Point. Ghost crabs (Ocypode quadrata) inhabit sandy beaches and can be found
on all three refuges. Salt ponds, mangroves, and lagoons are home to blue crabs (Callinectes
sapidus), which are strictly aquatic, as well as the semi-aquatic mangrove crabs (Aratus pisonii) and
fiddler crabs (Uca spp.) are all found on Sandy Point as well as the great land crab (Cardisoma
guanhumi) which is found in low lying estuarine areas within 5 km of the coast. Soldier (hermit) crabs
(Coenobita clypeatus) are common on all three refuges, are terrestrial except during the breeding
phase, and are found in coastal scrub, mangrove forests, riparian zones and upland forests. Crabs
are an important link in ecological food chains, and some species are directly exploited by humans.
Ghost and fiddler crabs, for example, are valuable food resources for some species of shorebirds.
Soldier crabs, meanwhile, are frequently collected for pets and for fishing bait, while blue crabs and
great land crabs are harvested for food in the USVI (DFW 2005; Lombard pers comm.).
The Virgin Islands are home to a number of indigenous species of spiders, the largest and most
visible of which is the tarantula (Cyrtopholis bartholomei). Other prominent spiders include the golden
weaver spider (Nephilia clavipes), silver argiope (Argiope argentata), spiny-bodied spider
(Gasteracantha tetracantha), and orchard spider (Leucauge regnyi). Little is known of their
conservation status (DFW 2005).
Amphibians
Five native species of amphibians—frogs, treefrogs, and toads—inhabit the USVI, four of which are found
on St. Thomas, three on St. Croix, and five on St. John (one of which is believed to be extirpated). Three
nonnative amphibians have also been introduced to and become naturalized on the three main islands.
The status and distributions of the native species are not well documented, although one species
(Eleutherodactylus lentus) is endemic and is listed as endangered on the International Union for the
Conservation of Nature’s Red List of Threatened Species (IUCN et al. 2004).
The presence and distribution of amphibians on the three refuges are uncertain, though a recent
herpetological survey revealed the presence of Eleutherodactylus lentus at Sandy Point. Threats to
amphibian populations in the U.S. Virgin Islands include habitat loss, modification, degradation, and
fragmentation as well as predation and competition from introduced species (DFW 2005).
Reptiles
While the terrestrial reptiles of the cays in the USVI are almost entirely undocumented, they have
been inventoried on the main islands, and include one amphisbaenid, 11 lizards, four snakes, and
two chelonians. Three lizards are endemic to St. Croix. One lizard and one snake are federally
endangered, while two other species are proposed as locally threatened. Baseline information is
lacking on the abundance, distribution, and basic ecological requirements of reptiles to effectively
conserve and manage them in the USVI. Much of the existing information on the USVI’s terrestrial
reptiles is several decades old, and is incomplete or dated (DFW 2005).
Draft Comprehensive Conservation Plan 39
The species of greatest concern on the USVI are the tree boa (Epicrates monensis granti), St. Croix
ground lizard (Ameiva polops), slipperyback skink, (Mabuya sloanii), and the amphisbaena
(Amphisbaenia fenestrata). Other species of concern include the Puerto Rican racer (Alsophis
portoricensis) and blind snake (Typhlops richardi). There are two introduced species of management
concern in the USVI: the red-eared slider (Trachemys scripta) and in St. Croix the Ameiva exsul
(Lombard pers comm.).
The Virgin Islands amphisbaena is considered a legless lizard. Its abundance and distribution within
the USVI are unknown because of the difficulty in locating it. Of the two species of ground lizard
found in the USVI, the common ground lizard is native to St. Thomas and St. John, and recently
introduced to St. Croix, while the St. Croix ground lizard, having been extirpated from the island for
which it is named, is now restricted to three cays off St. Croix. The St. Croix ground lizard is
discussed more extensively under the Green Cay NWR section.
Four species of anoles are found in the USVI, of which only one, the abundant St. Croix anole (Anolis
acutus), occurs on St. Croix. The St. Croix anole forages on the ground and perches on tree trunks
from just above the ground to 10 feet high. It is distributed across a wide range of habitat types and
structures on St. Croix (DFW, 2005), and is abundant at Sandy Point NWR (Lombard pers comm).
The crested anole (Anolis cristatellus) is distributed across a wide range of habitats on St. Thomas
and is abundant on Buck Island (Lombard pers comm).
The green iguana (Iguana iguana) is native to Central and South America, but its present distribution
extends across the Caribbean, although it is absent from most uninhabited cays in the USVI.
Zoologists believe that this species was introduced to the islands by pre-Colombian Indians, although
it may also have floated here; iguanas are good swimmers. The populations at Cabo Rojo and
Laguna Cartagena national wildlife refuges on Puerto Rico are most likely from escaped or released
pets. The green iguana inhabits a wide variety of xeric and mesic habitats. It is a large, charismatic
lizard and a popular tourist icon. It is fairly common in the USVI, particularly around restaurants and
tourist beaches where it basks in trees, poses for photographs, and readily accepts handouts. Many
consider it to be a pest species (DFW 2005).
Two species of dwarf geckos occur in the USVI. The common dwarf gecko (Sphaerodactylus
macrolepis) occurs on the major islands, while the St. Croix dwarf gecko (S. beattyi) is found only in
certain areas of St. Croix and nearby cays. Two other gecko species in the USVI are introduced—
the Mediterranean house gecko (Hemidactylus mabouia) and the fat-tailed gecko (Thecadactylus
rapicauda), which is only present on St. Croix. Their impact on native reptile and amphibian
populations is unknown (DFW, 2005). The common dwarf gecko and the Mediterranean house
gecko are both found on Sandy Point and Green Cay (Lombard pers comm.).
The slipperyback skink (Mabuya sloanii) is listed as territorially endangered due to a lack of recent
records. The apparent absence of this species from the major islands is likely due to the presence of
the introduced Indian mongoose. The skink is found in low to moderate numbers on Buck Island and
a single individual was reported on Green Cay in September 2000 (Lombard 2001).
The federally endangered Virgin Islands tree boa (Epicrates monensis granti) is a semi-arboreal
snake with a long history of extirpation and decline. In the USVI it is precariously confined to extreme
eastern St. Thomas, though as part of recovery efforts a small population has recently been
introduced to an undisclosed cay in the USVI. The Puerto Rican Racer (Alsophis porticensis nicholsi)
is believed to be a subspecies found only on Buck Island. During most site visits to Buck Island, at
least one individual has been observed.
40 Sandy Point, Green Cay, and Buck Island National Wildlife Refuges
The terrestrial red-footed tortoise (Geochelone carbonaria) is widespread in tropical South
America, and was