Species Assessment for Western Long-Eared Myotis (Myotis Evotis) in Wyoming
Author(s):Publication Date: 2004-08
Douglas A Keinath
Tags: BLM, WLCI Agency Report, WLCI
Myotis evotis (long-eared myotis), a former Category 2 Candidate, is currently recognized by
several federal and state agencies as a sensitive species, in part because very little information
exists to provide evaluations on population status and viability locally or rangewide.
Primary threats to M. evotis are roost disturbance (especially that leading to loss or destruction
of roosting structures), habitat alteration, and toxic chemicals. Roost disturbance (especially of
maternity roosts and hibernacula) can take the form of direct human contact or alternation of the
roost environment. Habitat alteration refers to modification of any component of the required
habitat mosaic, (e.g., presence and quality of open water, roost structures, and coniferous forest
stands) that might directly decrease suitability for bats or indirectly affect bats by altering prey
availability or modifying how those components relate to each other spatially. Chemicals refer
primarily to pesticides and toxic impoundments from resource extraction, which can cause direct
bat mortality and reduce populations of insect prey.
It is important to determine presence and abundance of M. evotis within Wyoming, and then
determine habitat associations in order to apply proper conservation management for this species.
Continual and consistent monitoring of known populations will help define local populations and
establish habitat-use. Once these specific habitat features are determined, management directions
should insure that key life history stages are not disturbed, the habitat mosaic is preserved for
persistence of these populations, and exposure to potentially detrimental chemicals is eliminated.
More specific issues of conservation concern are discussed in greater detail later in this
assessment. Fulfilling the information needs listed at the end of this document will clarify
population status and contribute to refining these conservation goals.