Bats in the Basin and Beyond

This article was originally published in The Midden – Great Basin National Park: Vol. 17, No. 2 , Winter 2017.

Releasing a recently banded Mexican free-tailed bat.

NPS Photo

By Kathleen Slocum, Biological Science Technician

Great Basin National Park’s Southern Nevada Public Land Management Act funded project, “Can land managers prevent the ‘inevitable collapse’ of bats in the western US?” has just finished its first of five field seasons. The overarching goals of the project are to locate and protect important bat roosts, derive demographic information about local bat populations, and educate and engage the public in bat conservation. Data gathered will help managers both locally and regionally better mitigate the growing threats to bat populations and manage bat habitats.

What makes this project unique is its scale; the study area includes the valleys and mountain ranges adjacent to the park, and has interagency collaboration built into its framework. Before white-nose syndrome (WNS) spread to Washington state in 2016, White Pine County, NV in which Great Basin NP is located, was ranked the 10th most susceptible county west of the Mississippi for WNS based on potential roost sites, bat species, and climate suitability (Ihlo 2013). Millard County, UT, and Tooele County, UT both border White Pine County and were ranked in the top 14 counties for susceptibility. As complex threats to bats continue to affect our landscape, we hope commensurate efforts like this SNPLMA project will provide managers the necessary tools to conserve and protect bats at the landscape-scale.

A main focus of our efforts has been in deploying passive integrated transponder (PIT) tag arrays at several major Townsend’s big-eared bat (Corynorhinus townsendii) maternity roosts, such as the one in Lehman Caves. Townsend’s big-eared bats have been shown to host the WNS causative fungus, Pseudogymnoascus destructans (Pd). This species is also known to share roosts with other bat species that are susceptible to developing WNS.

Bats are trapped as they exit the roost and injected with a 12 mmlong PIT tag. A small computer and antenna then logs individuals as they enter and exit the roost. The dataset gathered will provide novel baseline information about the timing and fidelity of roost use by bats in and near the park, as well as important life history data like survival and recruitment. Similar arrays are on caves with Townsend’s roosts managed by the US Forest Service and Bureau of Land Management within White Pine County.

Bat found in one of the park caves.

NPS Photo

The park is also helping with a mark-recapture project studying Mexican free-tailed bats (Tadarida brasiliensis) that roost in a cave close to the western park boundary from May-October. This species migrates in the spring and fall. The continental-scale connections between their roosts is poorly understood. Over the last three years, the Nevada Department of Wildlife and partners have outfitted 30,000 bats with wing bands, which uniquely identify them as part of our Nevada roosting population.

Migratory bats like Mexican free-tailed bats have been heavily impacted by wind-energy development; this project will better inform wind development and bat conservation as wind energy continues to expand across the West.

Landscape-scale bat studies are also becoming a focus within the Mojave Inventory and Monitoring Network. The first network bat blitz was performed at Grand CanyonParashant National Monument this past June. The area is a junction of the Colorado Plateau and Mojave ecoregions, very remote, and is incredibly biologically diverse. Twenty-five participants from the NPS, Arizona Game and Fish, and university partners performed three nights of trapping at 11 sites. Twelve species were caught in the hand, and there were potentially two more captured acoustically. The blitz was highly successful at providing a baseline assessment of bat diversity in that park and region. Aside from the science, a profitable aspect of this bat blitz was the strong emphasis on intra-agency networking. A great foundation was built for future bat work in the network parks.

Reference
Ihlo, C. M. 2013. Predicting the spread of white-nose syndrome in bats. PhD diss., Duke University.