Coastal Habitat Modification - American Samoa

Coastal habitats are utilized and altered for a suite of human uses. Habitat modification is here defined as the alteration or removal of geomorphic structure as a result of human use. This includes several habitat-modifying features like seawalls, piers, breakwaters, dredged areas, artificial land (i.e., filled wetlands), and offshore structures. This data layer represents the presence of habitat modification in shallow waters of American Samoa. The presence of habitat-modifying features were mapped by combining several existing datasets derived primarily from satellite and aerial imagery, including the following datasets: benthic habitat maps (NOAA Center for Coastal Monitoring and Assessment (CCMA), 2005); and NOAA Environmental Sensitivity Index (ESI) line data (NOAA Office of Response and Restoration (OR&R), 2003). The layer represents the presence or absence of habitat modification, with a cell size of 250 m. Relevant man-made features were extracted from each individual dataset and saved (features classified as artificial and dredged areas in NOAA benthic habitat maps; coastal segments designated as man-made structures and riprap in NOAA ESI line data). The resulting polygon datasets were merged together. A field was added to all vector layers with a value of 1 for each feature to represent the presence of habitat modification. Vector data were then converted to 250-m rasters and combined into a mosaic.