Evaluating the effects of anthropogenic land use and habitat fragmentation on bat diversity and activity in the Oak Openings Region

Bats are critically important for their control of insects but are experiencing population declines. The biggest reason for these declines is anthropogenic land use. Despite negative impacts, anthropogenic land use has variable impact on bats, with tolerance for more developed areas being species dependent and varying depending on the spatial or temporal scale. Previous studies on land use and bats lack spatial variability and are often single year. My goal was to determine how habitat factors related to human land use impact bat activity and species richness at multiple spatial scales over a period of several years. This research was conducted in the Oak Openings Region, which is a highly developed mixed-use region with high biodiversity that serves as important bat habitat. Specific objectives included determining (1) changes in bat activity and species richness over time, (2) differences in bat activity and species richness between protected and non-protected areas, (3) how factors related to human land use impact bat activity and species richness, and (4) to map current bat habitat suitability and see how it may change in the future. Calls increased each subsequent year during the 2019-2021 period, showing a trend of consistently increasing bat activity. However, during 2011-2019 bat activity significantly decreased. Protected areas had higher species richness and activity than unprotected areas. Higher activity and species richness were found in areas with greater percent upland prairie, sand barrens, and savanna and less floodplain and conifer forest and wet prairie. Activity was higher with less structural clutter at 3-6.5 m, lower understory height, taller canopy height, more canopy cover, and more structural clutter 0-3 m. Number of habitats was positively associated with bat species richness and activity along transects, but negatively associated with activity at stationary points. An opposite trend was observed for cropland. Activity and species richness along transects was higher when at least one side of the road had natural habitat. Variables having high impact on suitability included percent savanna and upland forest, distance to agriculture, May NDVI, total annual precipitation, mean diurnal range, and mean annual air temperature. Total percent suitable habitat did not change much between current models and 2050 predicted climate change models, although suitable habitat patches changed in location and level of suitability. These results demonstrate that measuring bat activity and species richness using a variety of spatial and temporal scales allows detection of changes in populations over time and identification of the habitat and environmental variables that are most important to bat populations