Scientists Develop Marine Habitat Maps for the Virgin Islands National Park and the Virgin Islands Coral Reef National Monument in St. John, U.S. Virgin Islands
Coral reef ecosystems in the U.S. Caribbean are under increasing pressure from environmental and anthropogenic stressors. Mitigating these threats requires that resource managers understand the distribution of coral reefs, making benthic habitat mapping an integral part of ecosystem-based approaches to management.
Scientists from NCCOS, in partnership with the U.S. National Park Service, recently created habitat maps for the Virgin Islands National Park and the Virgin Islands Coral Reef National Monument in St. John, U.S. Virgin Islands. Thirty-two distinct habitat types within 12 zones were mapped using heads-up interpretation of aerial imagery for shallow-water areas (< 30 m), and semi-automated classification of acoustic imagery (collected by the NOAA R/V Nancy Foster) for moderate-depth areas (30 – 60 m). This effort marks the first time moderate-depth habitats have been mapped south of St. John, providing managers with a snapshot of this environment which is dominated by rhodoliths and other algaes. St. John’s shallow-water habitats, on the other hand, were mapped previously in 1999. Comparisons indicate that live coral cover has declined, while seagrass beds have increased measurably since the last map iteration. The standardized protocols used in this effort will not only enable scientists and managers to compare coral reef ecosystems around St. John over time, but also compare them to reef habitats throughout the U.S. Territories. Products from this mapping effort are available online at (Benthic Habitat Mapping off St. John, U.S. Virgin Islands National Park and Virgin Islands Reef National Monument), as are the products from the previous shallow-water mapping effort (Benthic Habitat Mapping of Puerto Rico and the U.S. Virgin Islands).