Yuma Myotis (Myotis yumanensis) Conservation Status Review
Review Date = 09/25/2018
ScoreF - 20,000-200,000 km squared (about 8,000-80,000 square miles)
Comment65,125 square Kilometers from Natural Heritage Program range maps
ScoreE - Relatively Stable (±25% change)
CommentSpecies readily uses buildings and bridges as active season roosts, so any potential decrease in tree or rock outcrop roost has likely been offset through use of these structures. Therefore, it is unlikely a decline in available habitat has occurred over time.
ScoreU - Unknown. Short-term trend in population, range, area occupied, and number and condition of occurrences unknown.
CommentNo data on trends available. No records of this species exist in MTNHP's databases prior to 2006.
ScoreB - Moderate and imminent threat. Threat is moderate to severe and imminent for a significant proportion (20-60%) of the population or area.
CommentRecently this species has been observed with symptomatic WNS. It remains to be seen if differences in hibernacula used by western populations will change disease transmission dynamics and mitigate the effects of this disease on populations of this species in Montana. If impacts are similar to eastern species, extirpation is possible.
SeverityModerate - Major reduction of species population or long-term degradation or reduction of habitat in Montana, requiring 50-100 years for recovery.
CommentThe extent of WNS impacts to western bat species are currently unknown. If the disease dynamics are similar to the east coast, we may see declines of up to 100% for this species (High). Because many of our bats overwinter outside of caves, disease transmission and effects may differ and moderate population level impacts. Until we can quantify this better, the threat appears to be of Moderate severity, with a major reduction of population and recovery taking up to 100 years.
ScopeModerate - 20-60% of total population or area affected
CommentVery few of our bats hibernate in caves and mines so the extent of WNS impacts to the state’s population are difficult to quantify. Given the disease’s impacts on other related species, WNS will likely impact more than 20% of the population.
ImmediacyModerate - Threat is likely to be operational within 2-5 years.
CommentBased on the average rate of spread, we should expect to detect WNS or the causal pathogen to reach Montana within 5 years.
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).
CommentSpecies is long lived and has low fecundity. As these animals can fly, dispersal to and recolonization of extirpated populations is possible.
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.
CommentDuring the active season species uses a variety of habitats with roosts and water as limiting factors. Hibernacula are unknown in Montana but likely include caves, mines, and rock outcrops including talus slopes.
Raw Conservation Status Score
3.5 + 0 (geographic distribution) + 0 (environmental specificity) + 0 (long-term trend) + -0.75 (threats) = 2.75