STATUS OF CAVE-DWELLING BATS IN MARYLAND: IMPORTANCE OF MARGINAL HABITATS'

Caves, mines, and tunnels may serve as nurseries, hibernacula, or temporary roosting sites for many North American species of bats. In Maryland, such structures are used as hibernacula and roosting sites by at least 6 species: the little brown bat (Myotis lucifugus), Keen's bat (M. keenji), Indiana bat (M. sodalis), smallfooted bat (M. leibii), eastern pipistrelle (Pipistrellus subflavus), and big brown bat (Eptesicus fuscus).2 However, caves are rare, unique, and fragile habitats (Maser et al. 1979). Many populations of cave-dwelling bats have been adversely affected locally by pesticide or other chemical pollution, cave closures, vandalism, impoundments, or speleological activities (Humphrey 1978, Tuttle 1979, LaVal and LaVal 1980, Clark 1981). In order to provide baseline management information on the distribution and numbers of cave-dwelling bat species in Maryland, we surveyed most of the caves, mines, and tunnels in the state.