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Wyoming Natural Diversity Database

Heritage Rank

WYNDD uses a standardized ranking system coordinated by NatureServe to indicate the probability of extirpation, at both the global and state scales, of each plant and animal taxon. The following letters denote the spatial scale at which a taxon's status is scored :

G = Global rank assigned by NatureServe: range-wide probability of extinction for a species
S = Subnational (state/jurisdiction) rank assigned by WYNDD biologists for Wyoming
T = Trinomial rank: refers to the range-wide probability of extinction for a subspecies or variety

These letters are each followed by a numeric, 1-5 score:
1 = critically imperiled
2 = imperiled
3 = vulnerable
4 = apparently secure
5 = secure

Some taxa receive non-numeric scores, indicating special situations:
H = possibly extinct or extirpated
A = Accidental or vagrant: taxon appears irregularly and infrequently
X = presumed extinct or extirpated
U = Uncertain status: taxon possibly in peril but more information is needed

Some taxa may also receive rank modifiers, indicating other special situations:
B = Breeding rank: indicates the status of a migratory species during the breeding season; applied only to animals
N = Non-breeding rank: indicates the status of a migratory species during the non-breeding season; applied only to animals
Z = Rank not applicable: indicates that a migratory species is essentially absent or unrankable for the season in question (used with "B" or "N"); applied only to animals
Q = Questions exist regarding the taxonomic validity of a species, subspecies, or variety
? = Questions exist regarding the assigned numeric score

For more information visit the NatureServe conservation status page.

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