Assessing Cave Bat Populations and Monitoring for White-Nose Syndrome

By Kristy Mobley

White-Nose Syndrome (WNS) is an emerging fungal disease that has decimated bat populations across eastern North America. FWRI researchers are working with other biologists in FWC on a multi-year project to assess the size and distribution of cave bat populations in Florida prior to the appearance of WNS in the state.  The team also is testing bats and cave substrates for the presence of the fungus that causes WNS, and working to educate the public about the disease and how to limit its spread into Florida.  Gathering details about these bat populations and cave characteristics will allow FWC to improve response actions if WNS reaches Florida.

Tri-colored Bat (Perimyotis subflavus) in a northwest Florida cave

FWRI researchers visit caves each winter to record the number and species of bats present. While in the cave, they also document other cave characteristics including ambient temperature, presence of water, signs of past flooding, and evidence of human disturbance.  In 2016, researchers visited 139 caves and observed 1,006 tri-colored bats (Perimyotis subflavus) and over 50,000 southeastern myotis (Myotis austroriparius).  Nearly all of the southeastern myotis were located in a single cave, while most tri-colored bats were found in small groups and in many caves.

At several caves that are historically important roost sites, the researchers also test for the presence of the WNS fungus by swabbing the muzzle and wings of bats as well as small areas of the cave walls or floor. The swab samples are tested by the USGS National Wildlife Health Center and, fortunately, the WNS fungus still has not been detected in Florida.  Sampling for the WNS fungus will continue indefinitely, but fieldwork for the bat population assessment will be completed this coming winter.