ScoreE - 2,500-10,000 individuals
CommentApproximately 5,000 individuals within the state (MTFWP)
ScoreF - 20,000-200,000 km squared (about 8,000-80,000 square miles)
Comment140,697 square Kilometers from Natural Heritage Program range maps
ScoreA - Very Large Decline (decline of >90%, with <10% of population size, range extent, area occupied, and/or number or condition of occurrences remaining)
CommentPrior to European arrival, upwards of 100,000 sheep could have existed in the state. If this estimate is accurate, populations have declined by around 95%.
ScoreE - Stable. Population, range, area occupied, and/or number or condition of occurrences unchanged or remaining within ±10% fluctuation
CommentIn aggregate sheep numbers appear to be stable or slightly increasing (Montana Bighorn Sheep
Conservation Strategy), although local declines due to disease outbreak continue to occur.
ScoreF - Widespread, low-severity threat. Threat is of low severity but affects (or would affect) most or a significant portion of the population or area.
CommentMortality events caused by pneumonia are the primary concern for viability of isolated populations.
SeverityLow - Low but nontrivial reduction of species population or reversible degradation or reduction of habitat in area affected, with recovery expected in 10-50 years.
CommentWithout management assistance, some populations could take decades to recover from mortality events
ScopeModerate - 20-60% of total population or area affected
CommentMuch of the population is at risk of contracting pneumonia. Approximately 25 of hte 45 (56%) populations outside GNP are exposed to domestic sheep to some extent. Approximately 14 of the 45 (31%) populations are exposed to road mortality.
ImmediacyHigh - Threat is operational (happening now) or imminent (within a year).
ScoreB - Moderately Vulnerable. Species exhibits moderate age of maturity, frequency of reproduction, and/or fecundity such that populations generally tend to recover from decreases in abundance over a period of several years (on the order of 5-20 years or 2-5 generations); or species has moderate dispersal capability such that extirpated populations generally become reestablished through natural recolonization (unaided by humans).
ScoreC - Moderate. Generalist. Broad-scale or diverse (general) habitat(s) or other abiotic and/or biotic factors are used or required by the species but some key requirements are scarce in the generalized range of the species within the area of interest.
CommentFound in a diversity of habitats, but requires rugged escape terrain
Raw Conservation Status Score
3.5 + -0.25 (population size) + 0 (geographic distribution) + 0 (short-term trend) + 0 (threats) = 3.25