Effects of White Nose Syndrome on bat activity, diet composition and insect abundance in Southern Wisconsin
Amy K. Wray
University of Wisconsin, Madison
Our project, which focuses on investigating the effects of bat declines from White-nose Syndrome (WNS) on insect communities in Southern Wisconsin, has entered its third and penultimate field season. We continue to collect insect samples for microscope identification, bat guano for molecular analyses, and passive acoustic recordings to assess levels of bat activity in each area. Using the Kaleidoscope Pro software provided by the Wildlife Acoustics Scientific Product Grant, we have processed our acoustic data from 2015 and 2016 field seasons to assess bat activity levels at each of our 20 study sites. Our preliminary results from Kaleidoscope analyses indicate that 80% of our study sets met our a priori assumptions for having high Pre-WNS bat activity levels, with slight declines detected in 2016. We will use the data generated by Kaleidoscope's analyses, as well as data from future field seasons, to population occupancy models that will then be used to correlate bat activity with changes in insect community composition. As this year marks the first instances where dramatic declines in bat populations have been observed, the data that we are currently collecting for this field season will be essential for comparing differences between pre- and post-WNS years. We will continue to use Kaleidoscope to analyze bat activity levels at our sites in order to investigate correlates between bat diet composition, insect communities, and potential shifts related to disease-related bat declines. In the future, the results from our study will be used to inform management strategies and to promote bat bat conservation in Wisconsin and throughout the Midwestern region.
My primary research goals involve investigating the effects of bat declines from White-nose syndrome (WNS) on insect communities in Southern Wisconsin. For this project, I use a combination of insect community sampling, genetic analysis of bat guano, and acoustic monitoring to assess bat activity levels. At each of my 20 field sites, we use acoustic monitors to record nightly bat activity in zero crossing format. Additionally, for the recent 2017 field season, we also used SM4BAT detectors to record bat activity in full spectrum at sites with varying degrees of agricultural and forest landscape composition. These data, recorded in FS, will be used to better understand seasonal changes in bat foraging patterns and how these relate to landscape composition variables. All acoustic recordings will be assessed using Kaleidoscope PRO software in order to automatically classify and manually check bat identifications. From these analyses, spatial and temporal shifts in bat activity levels will be used to assess changes in bat communities and bat activity levels following declines related to WNS. The results from this study, including aspects involving acoustic monitoring, have been presented at the Midwest Bat Working group annual meetings, and will also be presented this year at the North American Symposium on Bat Research.
My current research on the effects of bat declines from White-nose syndrome (WNS) involves incorporating data from insect communities, bat acoustics, and next-generation sequencing of guano in Southern Wisconsin. Currently, we have processed acoustic data from 2015 and 2016. Based on preliminary results, we have found a significant decline in little brown bat activity across all sites, but did not detect a significant decline in big brown bat activity. These results are consistent with reports from the Wisconsin DNR and the Great Wisconsin Bat Count, which have reported declines in colonies throughout the state based on pre- and post-volancy bat counts. Insect counts from 2015-2017 have been completed, with nearly 2 million insect specimens identified and counted. In the near future of this project, this information will be used to assess whether bat acoustic activity correlates with changes in local insect abundances during the summer. The results from this study were presented this year at the NASBR meeting in Knoxville, Tennessee, and will also be presented next year at the American Society of Mammalogists meeting.