U.S. Virgin Islands Imperiled Terrestrial Species (Southeast Blueprint Indicator)

Reason for Selection The Caribbean Islands are recognized as a global biodiversity hotspot, with one of the highest numbers of globally threatened species among all such designated areas (CEPF 2019). This exceptional biodiversity is supported by the region’s unique geography and diverse habitats. The U.S. Virgin Islands (USVI) are home to hundreds of plant, fish, and bird species, including endangered species like the St. Croix ground lizard (Pholidoscelis polops) and other species that would benefit from conservation action like Wilson’s plover (Charadrius wilsonia) and the Antillean nighthawk (Chordeiles gundlachii). The species used in this indicator are identified as SGCN within the 2015 USVI Wildlife Action Plan and also include two endangered plant species. Each state and territorial fish and wildlife agency identifies a list of SGCN, which are considered species most in need of conservation action. Wildlife Action Plans focus on not only identifying SGCN but also important habitats, key threats, and needed conservation actions in order to proactively conserve these species. Understanding the distribution of native wildlife and plant species in the USVI—especially those that are listed as endangered or classified as SGCN—is essential for informing effective conservation strategies. This indicator identifies potential habitat for one amphibian, one reptile, eighteen birds, and two plant species and subspecies on the USVI SGCN list. While all listed species and SGCN warrant consideration, this indicator emphasizes places that support potential habitat for range-restricted species and narrow endemics that only occur in very small and often singular places, making them more vulnerable to extinction. For example, Egger’s century plant (Agave eggersiana) is a succulent plant, endemic to St. Croix, and was listed for protection in 2014 under the Endangered Species Act (USFWS 2022). Once widespread in the subtropical dry forests of St. Croix, habitat loss and longer dry spells have greatly reduced the population and it only persists in some small pockets on the island (USFWS 2022). In contrast, the Royal tern (Thalasseus maximus) is a seabird that nests along coastlines and has a much broader range. While it is considered a regional SGCN (Rice et al. 2019), the Royal Tern is found in 10 states within the Southeast region as well as along the Northeast coast. Input Data * [WildMon occupancy models for mapping species distributions across the U.S. Virgin Islands], provided by Dr. Marconi Campos-Cerqueira on March 28, 2025 (available on request by emailing [marconi@wildmon.ai]) [WildMon] is a nonprofit specializing in ecoacoustics, camera trapping, environmental DNA (eDNA), and artificial intelligence to deliver a holistic understanding of biodiversity patterns and guide effective conservation actions. In partnership with the U.S. Virgin Islands Department of Planning and Natural Resources, WildMon conducted a comprehensive wildlife monitoring project aimed at mapping biodiversity patterns across the region. The project focused on identifying locations of Species of Greatest Conservation Need. Through surveys at 140 sites, the team detected 70 species, providing critical data on rare, common, and invasive wildlife. A full list of all species included appears in the Full Species List section of this indicator’s chapter in the [Blueprint Development Process]. * 2012 [National Oceanic and Atmospheric Administration (NOAA) Coastal Change Analysis. Program (C-CAP) land cover files for the U.S. Virgin Islands] (St. Thomas, St. John, and St. Croix are provided as separate rasters) accessed 4-26-2022; learn more about [C-CAP high resolution land cover and change products.] * 2020 (v2.2.0) [LANDFIRE Existing Vegetation Type] (EVT) for Puerto Rico and the U.S. Virgin Islands (U.S. Insular Areas); [access the data] * Caribbean island size: available in the[Southeast Blueprint 2025 Ancillary Data Download]; see Appendix II of [the Southeast Blueprint 2025 Development Process] for details on how this layer was developed * Species range maps from U.S. Fish and Wildlife Service Environmental Conservation Online System (ECOS) for [Eggars agave] (Agave eggersiana), [St. Croix ground lizard] (Ameiva polops), [Catesbaea melanocarpa], and [Peperomia wheeleri] * [Southeast Blueprint 2025 extent] Mapping Steps * Sum the occupancy probabilities across all the WildMon occupancy models for SGCN, then resample to 30 m and snap to the Blueprint extent. * Convert the four ECOS species range vectors to 30 m rasters snapped to the Blueprint extent. We include these species ranges because they’re detailed enough to be used in the Blueprint and cover species not captured by the WildMon acoustic monitoring. Sum these values, then add them to the WildMon estimate of species richness to get a total species richness layer. * Select pixels classified as “Developed” or “Agriculture” in the LANDFIRE EVT “Lifeform” attribute and assign them a value of 0 to create a developed and agriculture mask. Then use the mask to set developed and agriculture in the combined weighted richness layer to 0. * Reclassify the richness layer to get the final indicator categories. Three of the species pulled from ECOS have very small ranges (St. Croix ground lizard, Eggar’s agave, and Catesbaea melanocarpa). Include any pixel with at least one of these species in the top indicator class. Note: For more details on the mapping steps, code used to create this layer is available [in the Southeast Blueprint 2025 Data Download] or [Caribbean-only Southeast Blueprint 2025 Data Download] under > 6_Code. Final indicator values Indicator values are assigned as follows: 4 = Very high species richness (top 10%) or presence of species with very small ranges 3 = High species richness (upper 10-30%) 2 = Medium species richness (above average) 1 = Low species richness (below average) 0 = Developed or agriculture Known Issues * The WildMon data only used acoustic sampling and cannot differentiate between species of coquí as well as some other species. Also, this sampling approach cannot detect species that are not vocal or were not vocal at the time of sampling. * The WildMon data had a low number of detections for some rarer species. This resulted in higher uncertainty in predictions for those species—especially in unsampled areas. * The indicator overprioritizes some altered areas that are difficult to separate with landcover data. For example, the landfill near Smalley Bay in St. Thomas is overprioritized. Disclaimer: Comparing with Older Indicator Versions There are numerous problems with using Southeast Blueprint indicators for change analysis. Please consult Blueprint staff if you would like to do this (email [hilary_morris@fws.gov]). Literature Cited Critical Ecosystem Partnership Fund (CEPF). 2019. CEPF 2019 Impact Report. [[https://www.cepf.net/sites/default/files/cepf-2019-impact_report-website.pdf]]. Rice, T. M., Crisfield, E., Terwilliger, K. 2019. Regional species of greatest conservation need in the Southeastern United States. Terwilliger Consulting, Inc. Prepared for the Wildlife Diversity Committee, Southeast Association of Fish and Wildlife Agencies. [[https://secassoutheast.org/pdf/SEAFWA_RSGCN_Final_Report_20190715.pdf]]. U.S. Fish & Wildlife Service. 2022. Eggers’ Century Plant (Agave eggersiana). U.S. Department of the Interior. Accessed May 16, 2025. [[https://www.fws.gov/species/eggers-century-plant-agave-eggersiana]].