Presentation: 2025 ND EPSCoR Annual conference 

October 21, 2025, NDSU Memorial Union, Fargo, North Dakota

Long-Term Acoustic Monitoring of Bat Populations in North Dakota

North American bat species have experienced major population declines due to White-Nose Syndrome (WNS), expansion of wind energy, anthropogenic development, and other factors. In North Dakota, these sources of population decline exist, but we have little to no information about trends in regional bat populations. If conservation efforts for bats are to succeed, data from long-term monitoring of populations is needed, particularly in understudied regions. The objective of this study was to gather and analyze passive acoustic monitoring data over an extended period (four years) to quantify trends in ND bat populations over time. In Summers 2019-2022, we used stationary acoustic monitoring to record bat echolocation at 60 sites across North Dakota. We analyzed data using Kaleidoscope Pro and Sonobat, with manual vetting of Myotis species. We quantified data across the study period to determine if any species showed changes in activity level with time. Our most striking finding was a highly significant decrease in the activity of the little brown bat, Myotis lucifugus, across the four-year sampling period, suggesting a rapid decline in regional populations of this species. Overall, this study provides important information on bat populations in the Northern Great Plains, and documents that a species that was once one of most commonly captured bats in the state has experienced substantive declines since the arrival of WNS in the region.