Products & Services
Species at Risk on DOD Installations
Species at Risk on DOD Installations > Methods
For the purpose of this report, species at risk are defined as native, regularly occurring species in the United States that are not federally listed under the U.S. Endangered Species Act, but are either:
- Candidates for listing under the U.S. Endangered Species Act, or
- Critically imperiled (rounded global rank of G1 or T1) or Imperiled (rounded global rank of G2 or T2), according to the NatureServe conservation status rank criteria.
Accordingly, three categories of species are used for most analyses in this report:
- Category 1: Federal Candidates
- Category 2: Critically Imperiled (rounded global rank = G1/T1)
- Category 3: Imperiled (rounded global rank = G2/T2)
Note that categories 2 and 3 are mutually exclusive (e.g. a species can only have a rank of G1/T1 or G2/T2), while species in category 1 may also have rounded global ranks of G1/T1 or G2/T2 (or other global ranks).
DOD installation boundaries are determined based on military
installations identified in the U.S. Geological Survey data set "Federal
Land Features of the United States" (National Atlas 2002). Because
the minimum map resolution of the USGS coverage is 640 acres or one square mile,
installations that are under this size are generally not shown. Species
at risk are considered to be located on a DOD installation(s)
if one or more population(s) of that species is known to occur:
- completely or partially (e.g. across installation border) within the boundaries of an installation; or
- within a 2 km (1.24 mi) distance of a DOD installation according to the USGS coverage described previously.
View > Nationwide