CCMA: Biogeography: Ecological Characterization of the NPS Salt River Bay National Historical Park and Ecological Preserve, U.S. Virgin Islands

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Ecological Characterization of SARI Historical Park and Ecological Preserve, USVI

Ecological Characterization of the NPS Salt River Bay National Historical Park and Ecological Preserve, U.S. Virgin Islands

Objectives

This characterization was conducted to synthesize all relevant historical information on the ecology of the Salt River Bay National Historical Park and Ecological Preserve (hereafter, SARI or the park). A comprehensive inventory of the parks ecosystems is required for successful management. To meet this need, the National Oceanic and Atmospheric Administration (NOAA) Biogeography Branch, in consultation with the National Park Service (NPS) and the Government of the Virgin Islands Department of Planning and Natural Resources (VIDPNR), conducted a spatially explicit ecological characterization.

Project Summary

SARI was created in 1992 to preserve, protect, and interpret nationally significant natural, historical, and cultural resources (United States Congress 1992). The diverse ecosystem within it includes a large mangrove forest, a submarine canyon, coral reefs, seagrass beds, coastal forests, and many other natural and developed landscape elements. These ecosystem components are, in turn, utilized by a great diversity of flora and fauna. The characterization of the park's ecological resources consists of three complementary components: a text report, digital habitat maps, and a collection of historical aerial photographs.

The text report is divided into sections based on physical characteristics (e.g. geology, water quality, currents), habitat types (e.g. land cover, coral reefs, mangroves), and major faunal groups (e.g. fish, birds). Each section includes an overview, methods, results, and a discussion of linkages with other components of the SARI ecosystem and surrounding environment.

A collection 184 aerial photographs of the Salt River area from the 1970's to 2000 were obtained from several federal agencies for this assessment (individual photos are available from NPS). Photographs from selected years were orthorectified and then used to create several habitat maps of the park. The most current photographs, from year 2000, were used to create a map of fifty terrestrial and marine habitat types visible in the imagery. This map covers the entire land (145 hectares) and mangrove area (19 hectares) within the park, all of the benthic habitat within Triton, Sugar, and Salt River Bays , and much of the offshore benthic habitats (250 hectares). This map, created with a minimum feature size of 10 by 10 meters, is the first detailed spatial characterization of the SARI ecosystem. The time series of photographs were used to create maps of changes to seagrass and mangrove distributions that have occurred over the last three decades. This group of maps and images were used to frame the discussion of each major habitat type, faunal group, or environmental category in the text report for this ecological characterization.

The aerial imagery, habitat maps, and text report that make up this assessment are complimentary, together providing research, monitoring, and management tools for the park. The images can be used to map additional ground features, document historical changes, and serve as a baseline against which future imagery may be compared. Habitat and land cover maps will assist with the design of monitoring schemes, selection of research sites, and identification of potential habitat for species of interest. The discussion and analyses contained in the text highlight established knowledge, explore spatial aspects of prior research, and identify information gaps and threats that may guide future monitoring and research. Together, these components provide a variety of information that will facilitate the current and future stewardship of the diverse resources contained within SARI.

Click image to enlarge:

The image above is based on geographic information system shapefiles representing benthic and land cover classifications for SARI in 2000. The park is located along the north-central shore of the St.Croix, U.S. Virgin Islands.