Relationships between bat occupancy and habitat and landscape structure along a savanna, woodland, forest gradient in the Missouri Ozarks

Many land-management agencies are restoring savannas and woodlands using prescribed fire and forest thinning, and information is needed on how wildlife species respond to these management activities. Our objectives were to evaluate support for relationships of bat site occupancy with vegetation structure and management and landscape composition and structure across a gradient of savanna to forest in the Missouri Ozark Highlands, USA. We selected study sites that were actively managed for savanna and woodland conditions and control areas on similar landforms that had succeeded to closed-canopy forest. We used Anabat detectors to survey bats during the summers of 2010, 2011, and 2012. We fit single-species site-occupancy models to estimate detection probability and site occupancy. We evaluated a priori hypotheses in an information theoretic approach by evaluating support for candidate models that included habitat, landscape, and management effects. Site occupancy of evening bats (Nycticeius humeralis) was negatively related to poletimber and sawtimber density and positively related to fire frequency, while northern long-eared bat (Myotis septentrionalis) site occupancy was positively related to poletimber density and negatively related to understory stem densities. Site occupancy of big brown bats (Eptesicus fuscus), eastern red bats (Lasiurus borealis), and tri-colored bats (Perimyotis subflavus) were mostly not related to local vegetation structure and site occupancy was high across the savanna, woodland, forest gradient. We found more consistent and larger effect sizes for landscape-scale than for habitat-scale relationships; therefore, land managers should be cognizant of large-scale patterns in land cover when making local management decisions for these species. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.