Roost-Site Selection of Bats in Northeast Missouri With Emphasis on the Endangered Indiana Bat (Myotis Sodalis)

Roosts are an integral habitat component for bat species and may dictate their survival and fitness. I used radiotelemetry to study the roosting ecology of the endangered Indiana bat, Myotis sodalis, at Deer Ridge Conservation Area (DRCA) in northeast Missouri from May through August 2001-2002. Due to the similarities in roost-site characteristics of forest-dwelling species of bat, and potential for niche-overlap, I also investigated the roosting behavior of four additional species: the little brown bat (Myotis lucifugus), northern bat (Myotis septentrionalis), evening bat (Nycticeius humeralis), and big brown bat (Eptesicus fuscus). A total of 183 day-roosts were located throughout the study: M. sodalis (N=91), M. septentrionalis (N=45), N. humeralis (N=28), E. fuscus (N=13), and M. lucifugus (N=6). Roost structures varied among species and also in the way in which they were utilized. Significant differences were detected in percent canopy cover, roost type (cavity/crevice vs. bark), and tree status (live vs. dead). During 2001 a population size of 450 adult M. sodalis was determined via simultaneous exit counts, making this the largest summer aggregation documented in Missouri. Though exit counts indicated a slightly smaller population in 2002, M. sodalis were present and exhibited fidelity to certain trees occupied the previous summer. The first documentation of M. sodalis at DRXA, a reproductively active female, was made in 1977. My results, obtained over two decades later, strengthen the need for further investigation of forest management strategies on M. sodalis summer roosting behavior, and increase the possibiity that such strategies may in fact be of benefit to the species