Species of Concern Home > Codes and Definitions
Data Requests > Codes and Definitions

CODES AND DEFINITIONS

The links listed below provide explanations for the codes used in our Species of Special Concern list and in our data request downloads.

Heritage Rank  |  Wyoming Contribution Rank  |  Federal Status  |  State Status

County  |  Managed Area  |  Range Context

Number of Occurrences  |  Abundance  |  Trend  | Intrinsic Vulnerability

Heritage Rank: 

WYNDD uses a standardized ranking system originally developed by The Nature Conservancy and its network of natural heritage programs (now coordinated by NatureServe [Arlington, Virginia]) 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: refers to the range-wide  probability of extinction for a species

T = Trinomial rank: refers to the range-wide probability of extinction for a subspecies or variety

S = State rank: refers to probability of extinction from WY for a given taxon
 

1 = Critically imperiled because of extreme rarity (often <5 extant occurrences) or because some factor makes it highly vulnerable to extinction
2 = Imperiled because of rarity (often 6-20 extant occurrences) or because of factors making it vulnerable to extinction
3 = Rare or local throughout its range or found locally in a restricted range (often 21-100 known occurrences)
4 = Apparently secure, although it may be quite rare in parts of its range, especially at the periphery
5 = Demonstrably secure, although it may be rare in parts of its range, especially at the periphery
 

H = Known only from historical records (typically pre-1970; varies by taxon)
A = Accidental or vagrant: taxon appears irregularly and infrequently
X = Believed to be extinct
U = Uncertain status: taxon possibly in peril but more information is needed
 

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

(back to top) 

Wyoming Contribution Rank: 

WYNDD has developed a ranking system that indicates the contribution of WY populations of a taxon to the rangewide persistence of that taxon. 

Very High = WY populations contribute greatly to the taxon’s rangewide persistence.  Typically applies to native, resident taxa with small continental ranges that are centered on WY

High = In combination with populations in adjacent states, WY populations contribute substantially to the taxon’s rangewide persistence.  Typically applies to native, resident taxa that are more secure in WY than elsewhere and have a moderate proportion of their continental range in WY 

Medium = WY populations contribute to the taxon’s rangewide persistence, but are apparently no more critical than populations in other states.  Typically applies to native, resident taxa that are as secure in WY as elsewhere and have a moderate proportion of their continental range in WY

Low = WY populations contribute minimally to the taxon’s rangewide persistence.  Typically applies to taxa that are more prevalent and secure in other states, and occur only intermittently or peripherally in WY

(back to top) 

Federal Status:

US Fish and Wildlife Service (USFWS):  The Endangered Species Act of 1973 directs the USFWS to identify and protect rare plants and animals.  The following categories are currently used to rank listed and candidate species. The candidate system was revised in 1996, eliminating the old categories of C2 and 3C. 

Endangered: In danger of extinction. For plants this applies to all of a taxon’s range; for animals this may apply to only a portion of a taxon’s range (EXPN = Experimental Population, Non-Essential)

Threatened: Likely to become Endangered in the near future.  For plants this applies to all of a taxon’s range; for animals this may apply to only a portion of a taxon’s range (EXPN = Experimental Population, Non-Essential)

Proposed De-list: Formally proposed for de-listing from Endangered or Threatened status; awaiting final rule

Proposed: Formally proposed for listing as Endangered or Threatened; awaiting final rule

Candidate (formerly C1): Existing biological information supports a formal proposal to list as Endangered or Threatened, but developing a listing regulation is precluded by higher priority listing activities.

Recent De-list: Recently de-listed from Endangered or Threatened status

Listing Denied: A formal proposal for listing as Endangered or Threatened was recently denied

Petitioned: A petition to list as Endangered or Threatened has been received by USFWS; awaiting USFWS review

USDA Forest Service (USFS): USFS has adopted policies to ensure that agency actions do not drive rare taxa towards listing as Threatened or Endangered under the Endangered Species Act.

USFS Region 2 and Region 4 have developed lists of “Sensitive Species” that warrant special attention on USFS lands (USDA FS 1991, 1994, 2003). Sensitive species are defined as “plant and animal species identified by the Regional Forester for which population viability is a concern as evidenced by: (a) significant current or predicted downward trends in population numbers or density, and/or (b) significant current or predicted downward trends in habitat capability that would reduce a species’ existing distribution.”  Sensitive species are usually designated for an entire region, but independent “Forest Sensitive” lists are maintained by some individual National Forests. The following codes are used to represent sensitive species designations by USFS:

S-USFS R2:  Sensitive in Bighorn, Black Hills, Medicine Bow, and Shoshone National Forests, and the Thunder Basin National Grassland 

S-USFS R4:  Sensitive in Bridger-Teton, Caribou, Targhee, Wasatch-Cache, and Ashley (including Flaming Gorge National Recreation Area) National Forests

SOLC: Species of Local Concern in the designated National Forest/Grassland

USDI Bureau of Land Management (BLM): BLM has adopted policies to ensure that agency actions do not drive rare taxa towards listing as Threatened or Endangered under the Endangered Species Act.

The BLM Wyoming State Office has established a list of “Sensitive Species” (SSL) warranting special attention on BLM lands (USDI BLM 2001, 2002, 2003). BLM Sensitive species are “species that could easily become endangered or extinct in the state”, including (a) species under status review by the FWS/ National Marine and Fisheries Service, (b) species whose numbers are declining so rapidly that Federal listing may become necessary, (c) species with typically small or fragmented populations, and (d) species inhabiting specialized refugia or other unique habitats. The following code is used to represent sensitive species designations by BLM:

WY BLM SSL:  On Sensitive Species List in all Wyoming BLM Field Offices

(back to top) 

State Status:

The text below applies only to animals.  At this time there is no system used by the state of WY to indicate the status of rare native plants.

Wyoming Game and Fish Department (WGF): The WGF uses a 1-4 “Native Species Status” score to rank the status of vertebrate species:

NSS1 = Populations greatly restricted or declining, extirpation possible.

-OR- Ongoing significant loss of habitat.

NSS2 = Populations declining, extirpation possible; habitat restricted or vulnerable but no recent or ongoing significant loss; species likely sensitive to human disturbance.

-OR-

Populations declining or restricted in numbers or distribution, extirpation not imminent; ongoing significant loss of habitat.

NSS3 = Populations greatly restricted or declining, extirpation possible; habitat not restricted, vulnerable but no loss; species not sensitive to human disturbance.

-OR-

Populations declining or restricted in numbers or distribution, extirpation not imminent; habitat restricted or vulnerable but no recent or ongoing significant loss; species likely sensitive to human disturbance.

-OR-

Species widely distributed; population status or trends unknown but suspected to be stable; on-going significant loss of habitat.

NSS4 = Populations greatly restricted or declining, extirpation possible; habitat stable and not restricted

-OR-

Populations declining or restricted in numbers or distribution, extirpation not imminent; habitat not restricted, vulnerable but no loss; species not sensitive to human disturbance.

-OR-

Species widely distributed, population status or trends unknown but suspected to be stable; habitat restricted or vulnerable but no recent or on-going significant loss; species likely sensitive to human disturbance.

-OR-

Populations stable or increasing and not restricted in numbers or distribution; on-going significant loss of habitat.

(back to top) 

County: 

WY counties in which rare species occur.  Vague or unsubstantiated county records are indicated by “?”.  County names in brackets indicate former range of now extinct taxa.  Records for Yellowstone Nat’l Park are listed by Park or Teton County.

Managed Area: 

Codes show federal and state managed areas in which rare plants are known to occur.  Blank entries indicate that a species is known only from other state or privately owned lands. Vague or unsubstantiated records are indicated by “?”.  Codes are as follows:

AFB = Air Force Base
BLM = Bureau of Land Management
NF = National Forest
NG =  National Grassland
NHS = National Historic Site
NM = National Monument
NP =  National Park
NRA = National Recreation Area
NWR = National Wildlife Refuge
SP = State Park

In addition, records reported from Wind River Indian Reservation are indicated by:

IR = Indian Reservation

(back to top) 

Range context: 

The extent and position of a taxon’s continental range relative to WY. 

Local endemic: continental range is no larger (approx.) than Natrona Co., WY (72 X 72 mi)
Regional endemic: continental range is no larger (approx.) than the state of WY
Widespread: continental range is much larger than the state of WY
Core: WY encompasses >50% of the continental range
Edge: WY encompasses <50% of the continental range
Disjunct: WY populations are widely isolated (by about 300 mi or more) from the main, contiguous portion of the continental range 

(back to top) 

Number of Occurrences: 

Number of extant (documented since 1970) and discrete reproductive populations of a rare plant in WY.

Very Low  = 1-5 occurrences
Low  = 6-20 occurrences
Moderate  = 21-75 occurrences
High  = >75 occurrences
Unknown

(back to top) 

Abundance: 

Number of individuals, or area of occupied habitat, of a rare plant in WY. 

Rare = <5000 individuals or <500 occupied ac.
Uncommon = 5000-50000 individuals or 500-5000 occupied ac.
Unknown

(back to top) 

Trend: 

Change in number of individuals, occurrences, or area of occupied habitat.  Historical refers roughly to the period 1850 - 1950.  Recent generally refers to the period since 1950.

Large decline = >50% decline in numbers, occurrences, or area
Moderate decline = <50% decline in numbers, occurrences, or area
Stable = no substantial decline or increase
Increase = any substantial increase in individuals, occurrences, or area
Unknown

(back to top) 

Intrinsic Vulnerability:

The susceptibility of a taxon to decline due to inherent biological factors.  Such factors include fecundity, population density, dispersal ability, pollinator limitations, competitive ability, likelihood of hybridization, and habitat specialization.  Intrinsic vulnerability is scored with an emphasis on conditions in Wyoming that may represent a subset of rangewide conditions.

High = Taxon restricted to 1 rare habitat type -OR- exhibits at least 2 of the following characteristics: very low population density, very low dispersal ability, very low fecundity, pollinator limitations, predisposition to disease

Moderate = Taxon restricted to 2-4 habitat types -OR- exhibits at least 1 of the following characteristics: very low population density, very low dispersal ability,  very low fecundity, pollinator limitations, predisposition to disease

Low = Taxon occurs in a variety of habitat types (usually all within 1 biome) -OR- has no life history traits that predisposes it to declines resulting from moderate environmental changes

(back to top)