Data format: Raster Dataset - ESRI GRID
File or table name: grasstypes91
Coordinate system: Universal Transverse Mercator
Theme keywords: fish, wildlife, habitat, trust species
| Gulf of Maine Habitat - Grassland, Shrub and Bare Ground | |
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Data format: Raster Dataset - ESRI GRID File or table name: grasstypes91 Coordinate system: Universal Transverse Mercator Theme keywords: fish, wildlife, habitat, trust species |
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Abstract:
This GRID represents the overall habitat values, within grassland, shrub, and bare ground cover types, in the U.S. portion of the Gulf of Maine watershed. Habitat values were derived for 91 priority trust species of the U.S. Fish Wildlife Service. Habitats for each species were mapped and ranked from actual sightings or by developing habitat suitability models reflecting environmental requirements for each species. Scores for each species were then added to derive the sum of scores for all species combined. The value for each cell reflects both the number of species using each cell and the relative habitat suitability for those species. |
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Metadata elements shown with blue text are defined in the Federal Geographic Data Committee's (FGDC) Content Standard for Digital Geospatial Metadata (CSDGM). Elements shown with green text are defined in the ESRI Profile of the CSDGM. Elements shown with a green asterisk (*) will be automatically updated by ArcCatalog. ArcCatalog adds hints indicating which FGDC elements are mandatory; these are shown with gray text.
This GRID represents the overall habitat values, within grassland, shrub, and bare ground cover types, in the U.S. portion of the Gulf of Maine watershed. Habitat values were derived for 91 priority trust species of the U.S. Fish Wildlife Service. Habitats for each species were mapped and ranked from actual sightings or by developing habitat suitability models reflecting environmental requirements for each species. Scores for each species were then added to derive the sum of scores for all species combined. The value for each cell reflects both the number of species using each cell and the relative habitat suitability for those species.
This data may be used to show valuable habitat for USFWS priority trust species in the U.S. portion of the Gulf of Maine watershed. The data may be used at a regional or local level to prioritize habitat protection by local, municipal, state or federal land protection organizations or to support grant applications for habitat protection. It may also be incorporated into local and regional planning to help identify and protect important fish and wildlife habitat.
ground condition
None
4R Fundy Rd.
The accuracy of the attributes is determined by the scale and quality of the data sets used, which may have errors in characterizing land cover, soil, or other environmental condition. Use of this data set at the local level (parcel or town level) should be supplemented by on-the-ground verification.
This raster data set is based on descriptive models, applied to available GIS datasets.
The coverage may omit useful habitat or erroneously identify habitat because of limitations of the source data and the models operating on those data. Habitat identification was limited by the spatial resolution of the underlying data and the quality and age of information available. The species may not be found in all the habitats shown, or may be found in additional areas; the information provided may not accurately portray most recent conditions. This data set only shows high value habitat for the species included in the analysis; important habitat may exist for other species not included in the analysis.
Data set accuracy generally corresponds to that of the 1:24,000 base data used to align the raster data.
Source is the numeric sum of values of habitat grids for 91 species.
Land cover
Grids corresponding to the overall habitat values for each of 4 general cover types (saline, freshwater, forested, grass/shrub/bare ground) were developed by: 1) assigning each of the cover classes of the land cover grid to the appropriate 1 of the 4 more general classes; 2) calculating the numeric values for each of the 4 output grids as the gomsum value of the cells having that general cover type (cells having the alternate cover types were scored '0'). The following steps were used to calculate the top portion of the habitat values for that general cover type. The value attribute table of each of the 4 grids was exported to a spreadsheet, in which the 'value' field is ordered from lowest numbered record (top of column) to highest (bottom of column) records. Then: 1) Add a column in which to calculate the product of the 'value' field (which is habitat quality) times the 'count' field (number of cells at each value) - these products are 'habitat units'. 2) Sum the 'habitat units', and calculate what the top increments of this would be (e.g., top half, top quarter). 3) Make another column and in it cumulatively add the 'habitat units' from top to bottom. 4) By inspection, look down the column to find the 'value' at which the cumulative habitat unit number is at or above the level of interest (e.g., half of the sum of habitat units (from step 2)). This grid value and higher values constitute that top increment of habitats, and may be so displayed or mapped.
Internal feature number.
ESRI
Relative overall habitat value, where larger numbers indicates increasing habitat value.
Count for each value.
Automatically generated.
4R Fundy Rd.
4R Fundy Rd
