Vegetation Classification and Mapping Project Report - USGS

USGS-NPS Vegetation Mapping Program
Colonial National Historical Park
Global Rank Codes and Definitions
Global ranks (i.e. range-wide conservation status ranks) are assigned at NatureServe’s
Headquarters or by a designated lead office in the Heritage/Conservation Data Center Network.
GX - Extirpated - Eliminated throughout its range, with no restoration potential due to
extinction of dominant or characteristic species.
GH - Historical - Presumed eliminated throughout its range, with no, or virtually no, likelihood
that it will be rediscovered, but with potential for restoration (e.g., Castanea dentata Forest).
G1 - Critically Imperiled - Critically imperiled globally. Generally 5 or fewer occurrences
and/or very few remaining acres or very vulnerable to elimination throughout its range due to
other factor(s).
G2 - Imperiled - Imperiled globally. Generally 6–20 occurrences and/or few remaining acres or
very vulnerable to elimination throughout its range due to other factor(s).
G3 - Vulnerable - Rare or uncommon. Generally 21–100 occurrences; either very rare and local
throughout its range or found locally, even abundantly, within a restricted range or vulnerable to
elimination throughout its range due to specific factor(s).
G4 - Apparently Secure - Uncommon but not rare. Apparently secure, but with cause for
long-term concern. May be quite rare in parts of its range, especially at the periphery; apparently
not vulnerable in most of its range
G5 - Secure - Demonstrably widespread, abundant, and secure. Common, widespread, and
abundant, although it may be quite rare in parts of its range, especially at the periphery; not
vulnerable in most of its range.
GNA - Rank not applicable - Common cultural, ruderal, planted, modified, managed, invasive,
and/or non-natural type that is not a suitable target for conservation activities.
GNR - Not Yet Ranked - Status has not yet been assessed.
GU - Unrankable - Status cannot be determined at this time.
G#G# - Rank Range - The actual rank of the element is within the range specified by the
numbers; however, the exact status of the rarity of the element is uncertain. For example, G2G3
indicates that the rank may be either G2 or G3.
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