Guidelines for Defining Biologically Important Bat Roosts: A Case Study from Colorado

Abstract

Conservation of roosts is regularly recommended as a strategy to decrease the risk of threats to local bat populations (e.g., white-nose syndrome). Determining whether a roost site plays a meaningful role in maintaining a local bat population can be difficult given the variability found in roost structure type, and use by season, duration, and sex. Here we provide land managers and biologists with guidelines to aid in the decision process for determining which roosts are biologically important in maintaining healthy bat populations at a local scale. We define methods for determining biologically important roost sites and provide a case study of their use on bat roosts in Colorado. To be considered biologically important, we suggest that a roost meet two primary criteria: 1) it is considered a hibernaculum, maternity roost, transient roost, colonial bachelor roost, or fall swarming site used by bat species that are gregarious roosters, hibernators, or are known to swarm, and 2) if the site is disturbed or lost, it could affect 5% or more of the local population of the species, as defined by the investigator. Additive measures to further evaluate the importance of the roost and assign higher conservation value include: 1) a roost used by a special status species and 2) large aggregations of bats where an estimated 20% or more of the local population is roosting or swarming at the site. We also provide definitions for the seasonality of roost types, examples of several real-life scenarios where management decisions have been made for roosts, and a worksheet that helps guide users through the process.

Acoustic surveys for local, free-flying bats in zoos: an engaging approach for bat education and conservation

“…During our acoustic sampling we documented seven bat species, which represents 50% of the bat fauna of Idaho (Keller 1985); six of which were species of conservation concern (IDFG 2017, Neubaum et al 2017, O'Shea et al 2018. Big brown bats were detected in every month and are not currently a species of conservation concern.…”

“…Such exhibits will help zoos stand out as conservation centers for local animals (Keulartz 2015). (IDFG 2017, Neubaum et al 2017, O'Shea et al 2018.…”

Species Richness and Seasonality of Bat Occupancy on Northwestern National Wildlife Refuges

“…We defined the winter period as 15 November-15 March (Neubaum et al 2006); we classified bats as overwintering or potentially overwintering if detected during that time period. We defined movement associated with seasonal dispersal as arrival in March through April (O'Farrell and Studier 1975), although early March is a known period of overlap between hibernation and transition periods (Neubaum et al 2017). We defined departure in the fall as between August (Fellers and Pierson 2002;O'Farrell and Studier 1980;McGuire et al 2012) and the first half of November.…”

“…On Sheldon Refuge, we also documented silver-haired bats as active year round. We additionally classified six species as likely overwintering because we detected them in early March, a period of overlap between hibernation and transition periods (Neubaum et al 2017),…”

Long-term bat abundance in sagebrush steppe

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