A GAP ANALYSIS OF U.S. VIRGIN ISLANDS May 15, 2013 Final Report Photo credit Alberto López A GEOGRAPHIC APPROACH TO PLANNING FOR BIOLOGICAL DIVERSITY U.S. Geological Survey USDA Forest Service International Institute of Tropical Forestry Caribbean Landscape Conservation Cooperative 1 THE U.S. VIRGIN ISLANDS GAP ANALYSIS PROJECT FINAL REPORT May 9, 2013 William A. Gould (PI) Research Ecologist, USDA Forest Service, International Institute of Tropical Forestry, Río Piedras, Puerto Rico 00926-1119 Mariano C. Solórzano-Thillet, Biologist and GIS Specialist Gary S. Potts, Remote Sensing Specialist Maya Quiñones, Cartographic Specialist USDA Forest Service, International Institute of Tropical Forestry Jessica Castro-Prieto, Ecologist IGERT Fellow-Department of Environmental Sciences University of Puerto Rico-Rio Piedras Campus Lisa D. Yntema U.S. Virgin Islands Contract Administration Through: USDA Forest Service, International Institute of Tropical Forestry, Río Piedras, Puerto Rico 00926-1119 Submitted by: William A. Gould Research Performed Under: Agreement No. 06HQPG0014 USDA Forest Service, International Institute of Tropical Forestry, 1201 Calle Ceiba, Río Piedras, Puerto Rico 00926-1119 U.S. Geological Survey, Biological Resources Division, Gap Analysis Program LIST OF PROJECT AFFILIATES U.S. Forest Service International Institute of Tropical Forestry United States Geological Survey Biological Resources Division Suggested citation: Gould WA, Solórzano MC, Potts GS, Quiñones M, Castro-Prieto J, Yntema LD. 2013. U.S. Virgin Islands Gap Analysis Project – Final Report. USGS, Moscow ID and the USDA FS International Institute of Tropical Forestry, Río Piedras, PR. 163 pages and 5 appendices. 2 TABLE OF CONTENTS DEDICATION 4 ACKNOWLEDGEMENTS 5 EXECUTIVE SUMMARY 6 INTRODUCTION 11 LAND COVER CLASSIFICATION AND MAPPING 26 PREDICTED ANIMAL SPECIES DISTRIBUTIONS AND SPECIES RICHNESS 71 LAND STEWARDSHIP 95 ANALYSIS BASED ON STEWARDSHIP AND MANAGEMENT STATUS 116 CONCLUSIONS AND MANAGEMENT IMPLICATIONS 157 PRODUCT USE AND AVAILABILITY 158 GLOSSARY 162 GLOSSARY OF ACRONYMS 163 LIST OF APPENDICES Appendix 1. List of example GAP applications. Appendix 2. Terrestrial vertebrate species of the U.S. Virgin Islands. Appendix 3. Terrestrial vertebrate species accounts and bibliography. Appendix 4. Species occurrence maps. Appendix 5. Species predicted distribution maps. 3 DEDICATION The U.S. Virgin Islands are the eastern most extension of U.S. lands and seas. They are small in area and number of inhabitants, but blessed with the beauty of the Caribbean land, seas and sky and the warmth of the people. The three larger islands and a number of small cays have a wealth of natural resources, including rare and endangered plants and animals; endemic species; forests, mangroves, beaches, coves, cays, seagrass beds and reefs — all habitats vital to resident and migratory birds and marine species. Land and seascape stressors of climate change, sea level rise and land use issues create a complex arena for managing natural resources. Assessing biodiversity and the state of the environment is critical to making sound decisions to preserve, conserve, and augment the wealth of natural resources for future generations. In that spirit, this report is dedicated to all those who devote time, energy, and ideas to the understanding, preservation, conservation, restoration, and enjoyment of the beauty and natural resources of the U.S. Virgin Islands. William Gould Principle Investigator 4 ACKNOWLEDGEMENTS This work has been accomplished with the assistance of a great number of people. Their support and enthusiasm for conservation has been inspirational. I would like to first thank Jaime Collazo for bringing the GAP approach to the region and collaborating with the International Institute of Tropical Forestry. The support provided the U.S. Forest Service International Institute of Tropical Forestry was very important. Thanks to Institute Director Ariel Lugo. Kevin Gergley, Program Manager of the USGS Biological Resources Division, National Gap Program in Moscow Idaho has strongly supported this work. The staff at the National Gap office, including Jocelyn Aycrigg, Jill Maxwell, Anne Davidson, and Nicole Coffey, have been a great and patient help. We have collaborated and received expertise and support from several people working in the Virgin Islands: including Brian Daley and Marcia G. Taylor at the University of the Virgin Islands; Laurel Brannick, Christy McManus and Zandy Hillis-Starr with the National Park Service; Carol Cramer-Burke with the St. Croix Environmental Association; people at the Island Resources Foundation; Renata Platenberg, Jennifer Valiulis, and Judy Pierce at the Department of Planning and Natural Resources Division of Fish and Wildlife; Claudia Lombard at the U.S. FWS Sandy Point National Wildlife Refuge; James Byrne and Shawn Margles at the Nature Conservancy; the U.S. Geological Survey National Wetlands Research Center; Magen’s Bay Authority; Brittany Barker, Ph.D. Candidate from the University of New Mexico; independent researchers and stakeholders, including Lisa Yntema, expert on birds from St. Croix; Russell Slatton from Geographic Consulting LLC; and Mario Francis from the Junior Gardening & Ecology Academy. Collaborators have help us coordinate meetings and provided information and suggestions to improve our work. They have also reviewed our products, supported our efforts, and shared their expertise as well as species occurrence and GIS data with us. We thank them all and hope these products will be useful in their work. Scientists at IITF have been a source of feedback, expertise and encouragement including Director Ariel Lugo, Project Leader Grizelle González, and other scientists Wayne Arendt, Eileen Helmer, Jean Lodge, Frank Wadsworth, Pete Weaver, and Joe Wunderle. I would like to thank all the people in the IITF GIS and Remote Sensing Laboratory for their support and enthusiasm, including Olga Ramos-González and Maya Quiñones. Finally, I would like to thank the primary Institute GAP staff who shared their time, enthusiasm, and expertise to make this project successful, including Gary Potts, Mariano Solórzano, Maya Quiñones, and Jessica Castro Prieto. 5 EXECUTIVE SUMMARY The U.S. Virgin Islands Gap Analysis Project has developed and compiled information of the U.S. Virgin Islands’ landcover, vertebrate occurrences, and natural history information, and land stewardship. It is based on methods developed by the National Gap Analysis Program to determine the degree to which animal species and natural communities are represented in the current mix of conservation lands. Those species or communities not well represented are considered conservation “gaps.” The purpose of the U.S. Virgin Islands Gap Analysis Project is to provide geographic and ecological information on the status of not only threatened or rare species, but the common species of the U.S. Virgin Islands. This provides land managers, government planning and policy makers, scientists, students, and the general public with information to make better decisions regarding land management and conservation. The U.S. Virgin Islands Gap Analysis project has four major components: Landcover mapping, documentation of vertebrate species distributions, documentation of land stewardship practices with respect to conservation, and an integrated analysis of these three elements. The databases of species occurrence, land cover, and stewardship for the USVI GAP are being integrated with the Puerto Rico Gap Analysis Project (PRGAP) (Gould et al. 2008) and the Puerto Rico-USVI Integrated Terrestrial-Aquatic Gap (Integrated Gap) (Gould et al. 2010) to allow regional analyses of terrestrial, freshwater, and marine habitats and biodiversity. The U.S. Virgin Islands (USVI) are located in the Caribbean just east of Puerto Rico in the northwestern most section of the Lesser Antilles. The USVI cover 350 km2 and include St. Thomas, St. John, St. Croix, and a number of cays. They harbor relatively high numbers of species and substantial levels of endemism, particularly among the reptiles. USVI GAP includes 153 species of terrestrial vertebrates: 118 birds, 21 reptiles, 7 amphibians and 8 mammals. These include endemic, breeding resident, breeding migrant, established exotic and nonbreeding migrant species. The majority are breeding residents. Breeding migrants include birds and marine turtles - which use terrestrial habitat for nesting. Ten to 20 percent of the amphibians and reptiles are endemic. We are following the traditional GAP approach, developing geospatial information and databases on land stewardship, species occurrence, and land cover. Landcover Traditionally, GAP projects have relied on satellite imagery from Landsat 5 TM and Landsat 7 ETM+ to provide the spatial and spectral information to derive land cover habitat maps at 30m spatial resolution. Puerto Rico GAP (Gould et al. 2008) incorporated the Landsat 7 ETM+ 15m panchromatic band to enhance the spatial resolution and infrared bands in order to improve the delineation of habitats at the sub-pixel level in complex tropical landscapes. Current Landsat 7 ETM+ imagery and scene acquisition is limited by the scan line correction (SLC) error, horizontal lines with no data that appear across the entire image since July 2003, and the Long Term Acquisition Plan (LTAP), the 6 use of a set of criteria that includes cloud-cover forecasts (Landsat Project Science Office, 1998) to guide Landsat image collections. These limitations make the