Natural Heritage Ranking

Montana Natural Heritage Program Ranking

Species have been evaluated and ranked on the basis of their global (range-wide) status, and their statewide status, using the standardized ranking system of the Natural Heritage Network (Association for Biodiversity Information 2001). For a more detailed description of the MTNHP ranking system visit the Montana Natural Heritage Program web site.

Common Name	Scientific Name	Global Rank	State Rank	Class
Blue Sucker	Cycleptus elongatus	G4	S2	B
Bull Trout	Salvelinus confluentus	G3	S2	A
Columbia River Redband Trout	Oncorhynchus mykiss gairdneri	G5T4	S1	A
Montana Arctic Grayling	Thymallus arcticus montanus	G5T1Q	S1	A
N. Redbelly X Finescale Dace	Phoxinus eos x phoxinus neogaeus	HYB	S3	C
Paddlefish	Polyodon spathula	G4	S1S2	A
Pallid Sturgeon	Scaphirhynchus albus	G1	S1	A
Pearl Dace	Semotilus margarita	G5	S2	C
Sauger	Stizostedion canadense	G5	S2	B
Shortnose Gar	Lepisosteus platostomus	G5	S1	C
Sicklefin Chub	Macrohybopsis meeki	G3	S1	B
Spoonhead Sculpin	Cottus ricei	G5	S3?	C
Sturgeon Chub	Macrohybopsis gelida	G2	S2	B
Torrent Sculpin	Cottus rhotheus	G5	S3?	C
Trout-perch	Percopsis omiscomaycus	G5	S2	C
Westslope Cutthroat Trout	Oncorhynchus clarki lewisi	G4T3	S2	A
White Sturgeon	Acipenser transmontanus	G4T1Q	S1	A
Yellowstone Cutthroat Trout	Oncorhynchus clarki bouvieri	G4T2	S2	A
Species Under Review
Shorthead Sculpin	Cottus confusus	G5	SU
Brook Stickleback	Culaea inconstans	G5	SU
Iowa Darter	Etheostoma exile	G5	SU
Brassy Minnow	Hybognathus hankinsoni	G5	SU
Plains Minnow	Hybognathus placitus	G5	SU
Burbot	Lota lota	G5	SU
Northern Redbellied Dace	Phoxinus eos	G5	SU
Pygmy Whitefish	Prosopium coulteri	G5	SU
Creek Chub	Semotilus atromaculatus	G5	SU

Montana Natural Heritage Program Ranking Definitions

Global/State Rank	Definition (G = Range-wide; S = Montana)
G1/S1	Critically imperiled because of extreme rarity or because of some factor(s) of its biology making it especially vulnerable to extinction.
G2/S2	Imperiled because of rarity or because of other factors demonstrably making it very vulnerable to extinction throughout its range.
G3/S3	Either very rare and local throughout its range, or found locally (even abundantly at some of its locations) in a restricted range, or vulnerable to extinction throughout its range because of other factors.
G4/S4	Apparently secure, though it may be quite rare in parts of its range, especially at the periphery.
G5/S5	Demonstrably secure, though it may be quite rare in parts of its range, especially at the periphery.
GU/SU	Possibly in peril, but status uncertain; more information needed.
GH/SH	Historically known; may be rediscovered.
GX/SX	Believed to be extinct; historical records only.
G#/S#	Indicates a range of uncertainty about the rarity of the species.

Other Codes:

A	Accidental in the state; including species (usually birds or butterflies) recorded very infrequently, hundreds or thousands of miles outside their usual range.
B	A state rank modifier indicating breeding status for a migratory species. Example: S1B,SZN -- breeding occurrences for the species are ranked S1 (critically imperiled) in the state, nonbreeding occurrences are not ranked in the state.
E	An exotic established in the state; may be native in nearby regions.
HYB	A hybrid of species.
N	A state rank modifier indicating non-breeding status for a migratory species. Example: S1B,SZN -- breeding occurrences for the species are ranked S1 (critically imperiled) in the state; nonbreeding occurrences are not ranked in the state.
P	Indicates the element may potentially occur in the state.
Q	Taxonomic questions or problems involved, more information needed; appended to the global rank.
R	Reported in the state, but lacking documentation that would provide a basis for either accepting or rejecting the report.
T	Rank for a subspecific taxon (subspecies, variety, or population); appended to the global rank for the full species.
Z	Ranking not applicable.
#	A modifier to SX or SH; the species has been reintroduced but the population is not yet established.
?	Inexact or uncertain: for numeric ranks, denotes inexactness.