Long-term bat abundance in sagebrush steppe

Area of Science:

• Ecology
• Conservation Biology
• Mammalogy

Background:

• Western North American bats face numerous threats, including habitat loss and disease.
• Population dynamics of Townsend's big-eared bats (Corynorhinus townsendii townsendii) and western small-footed myotis (Myotis ciliolabrum) in Idaho are poorly understood.
• Idaho provides critical bat habitat but is vulnerable to land-use changes and the emerging threat of white-nose syndrome.

Purpose of the Study:

• To investigate long-term population changes of two bat species in Idaho over 32 years.
• To establish baseline data for western small-footed myotis before the arrival of white-nose syndrome.
• To inform conservation strategies for bats in western North America.

Main Methods:

• Compiled data from 283 surveys across 49 hibernacula spanning 32 years.
• Analyzed population trends for Townsend's big-eared bats and western small-footed myotis.
• Accounted for increased detection rates in western small-footed myotis population trend analysis.

Main Results:

• Townsend's big-eared bat populations showed variable changes, increasing by 186% and 326% in two areas, but decreasing by 55% in another.
• Western small-footed myotis experienced a region-wide decline of 63% by 1998-1999 after adjusting for detection increases.
• Western small-footed myotis populations recovered by 2013-2014, potentially due to hibernacula closures.

Conclusions:

• Population trends for Townsend's big-eared bats differ across management areas.
• Hibernacula protection measures may aid western small-footed myotis recovery.
• This study provides crucial long-term data for two bat species of conservation concern in a vulnerable region.