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 the Main Hawaiian Islands. The Ocean Tipping Points (OTP) project mapped the presence of habitat-modifying features 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), 2007); NOAA Environmental Sensitivity Index (ESI) line data (NOAA Office of Response and Restoration (OR&R), 2001); maintained channels (NOAA, US Army Corps of Engineers (USACE), MarineCadastre.gov); and locations of offshore aquaculture. The layer represents the presence or absence of habitat modification, with a cell size of 500 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; all features from the maintained channels and aquaculture datasets). 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 500-m rasters and combined into a mosaic.

Shoreline of the Manu'a Islands (Manu'a, Ofu, Olosega, and Ta'u), American Samoa.

Managers have some ability to support healthy environmental conditions through strategic action at a local and regional scale, such as water quality. This layer synthesized spatial information for several managed conditions to create a relative score for how favorable a given location is for coral growth and survival. Environmental conditions contributing to this layer included: chlorophyll-a concentration, fish and herbivore biomass, turbidity (Kd490), and macroalgal cover. Covariation in these conditions was accounted for using principal component analysis (PCA) to form composite variables of conditions that have strong relationships with one another. The resulting principal components were averaged and scaled from 0 (worst) to 1 (best) to produce a coral favorability score for managed conditions. These data are provided as a raster with a resolution of 500 m for American Samoa, including Tutuila and the Manua Islands (Ofu, Olosega, and Tau).

This layer represents a proxy for sediment input to the nearshore marine environment from recent construction sites. Data are derived from the NOAA Coastal Change Analysis Program (C-CAP) High Resolution Change dataset from 2005 to 2010, except for Oahu and Lanai where data are for 2005 to 2011 (http://coast.noaa.gov/ccapftp/). The Ocean Tipping Points (OTP) project extracted pixels that changed from any undeveloped class to an impervious surface during the time period and calculated the area of new impervious surface within National Hydrography Dataset (NHD) HU12 watershed polygons. A Focal Statistics tool was used to calculate the mean area of new development within a 1.5-km circular radius of each offshore pixel. This area was dispersed offshore using a Gaussian decay function with distance from shore. Finally, values were linearly rescaled from 0-1 as this layer is a unitless proxy.

The overall condition of the environment is a combination of managed and non-managed factors. While it is difficult for managers to prevent coral bleaching events, reefs experiencing fewer stressors may recover more quickly than reefs that were highly stressed at the time of bleaching. The scores for managed (see layer "as_usgs_tutma_coralscore_mgt") and non-managed conditions (see layer "as_usgs_tutma_coralscore_nonmgt") were averaged to produce an overall environmental favorability score. This layer represents a relative score for how favorable overall conditions are for coral growth and survival from a scale of 0 (worst) to 1 (best) in the present climate scenario. These data are provided as a raster with a resolution of 500 m for American Samoa, including Tutuila and the Manua Islands (Ofu, Olosega, and Tau).

Many aspects of the environment are outside the control of local or regional resource managers. These conditions may require concerted global action to affect change (e.g., water temperatures) or cannot be controlled at all (e.g., wave power). This layer synthesized spatial information for several non-managed conditions to create a relative score for how favorable a given location is for coral growth and survival. Environmental conditions contributing to this layer included: marine calcite concentration (a proxy for ocean acidification), irradiance (photosynthetically available radiation, or PAR), thermal stress (annual severe bleaching threshold), wave power (per meter of wave front), and proximity to soils eroded by sea level rise. Projections exist for how some of these conditions may change over the next century based on the trajectory of global greenhouse gas emissions. This project explored how the relative favorability of non-managed conditions could change between the present climate scenario and the rest of the 21st century. This layer represents the future climate scenario for an intermediate emissions scenario (Representative Concentration Pathway 4.5), in which global greenhouse gas emissions peak mid-century and then begin to fall. Covariation in these conditions was accounted for using principal component analysis (PCA) to form composite variables of conditions that have strong relationships with one another. The resulting principal components were averaged and scaled from 0 (worst) to 1 (best) to produce the coral favorability score for non-managed conditions. These data are provided as a raster with a resolution of 500 m for American Samoa, including Tutuila and the Manua Islands (Ofu, Olosega, and Tau).

Managers have some ability to support healthy environmental conditions through strategic action at a local and regional scale, such as water quality. This layer synthesized spatial information for several managed conditions to create a relative score for how favorable a given location is for coral growth and survival. Environmental conditions contributing to this layer included: chlorophyll-a concentration, fish and herbivore biomass, turbidity (Kd490), macroalgal cover, and ocean-based pollution. Covariation in these conditions was accounted for using principal component analysis (PCA) to form composite variables of conditions that have strong relationships with one another. The resulting principal components were averaged and scaled from 0 (worst) to 1 (best) to produce a coral favorability score for managed conditions. These data are provided for the island of Guam as a raster with a resolution of 1500 m.

Many aspects of the environment are outside the control of local or regional resource managers. These conditions may require concerted global action to affect change (e.g., water temperatures) or cannot be controlled at all (e.g., wave power). This layer synthesized spatial information for several non-managed conditions to create a relative score for how favorable a given location is for coral growth and survival. Present-day environmental conditions contributing to this layer included: marine calcite concentration (a proxy for ocean acidification), irradiance (photosynthetically available radiation, or PAR), thermal stress (Degree Heating Weeks), and wave power (per meter of wave front). Covariation in these conditions was accounted for using principal component analysis (PCA) to form composite variables of conditions that have strong relationships with one another. The resulting principal components were averaged and scaled from 0 (worst) to 1 (best) to produce the coral favorability score for non-managed conditions. These data are provided as a raster with a resolution of 500 m for American Samoa, including Tutuila and the Manua Islands (Ofu, Olosega, and Tau).

The overall condition of the environment is a combination of managed and non-managed factors. While it is difficult for managers to prevent coral bleaching events, reefs experiencing fewer stressors may recover more quickly than reefs that were highly stressed at the time of bleaching. The scores for managed (see layer "as_usgs_tutma_coralscore_mgt") and non-managed conditions (see layer "as_usgs_tutma_coralscore_nonmgt_rcp45") were averaged to produce an overall environmental favorability score. This layer represents a relative score for how favorable overall conditions are for coral growth and survival from a scale of 0 (worst) to 1 (best) in the future climate scenario for an intermediate emissions scenario (Representative Concentration Pathway 4.5), in which global greenhouse gas emissions peak mid-century and then begin to fall. These data are provided as a raster with a resolution of 500 m for American Samoa, including Tutuila and the Manua Islands (Ofu, Olosega, and Tau).

Many aspects of the environment are outside the control of local or regional resource managers. These conditions may require concerted global action to affect change (e.g., water temperatures) or cannot be controlled at all (e.g., wave power). This layer synthesized spatial information for several non-managed conditions to create a relative score for how favorable a given location is for coral growth and survival. Environmental conditions contributing to this layer included: marine calcite concentration (a proxy for ocean acidification), irradiance (photosynthetically available radiation, or PAR), thermal stress (annual severe bleaching threshold), wave power (per meter of wave front), and proximity to soils eroded by sea level rise. Projections exist for how some of these conditions may change over the next century based on the trajectory of global greenhouse gas emissions. This project explored how the relative favorability of non-managed conditions could change between the present climate scenario and the rest of the 21st century. This layer represents the future climate scenario for a worst case emissions scenario (Representative Concentration Pathway 8.5), in which no action is taken to reduce global greenhouse gas emissions. Covariation in these conditions was accounted for using principal component analysis (PCA) to form composite variables of conditions that have strong relationships with one another. The resulting principal components were averaged and scaled from 0 (worst) to 1 (best) to produce the coral favorability score for non-managed conditions. These data are provided as a raster with a resolution of 500 m for American Samoa, including Tutuila and the Manua Islands (Ofu, Olosega, and Tau).