Bat Inventory of Assateague Island National Seashore

Gates, J; Johnson, Joshua

As significant nocturnal insectivores, bats are an integral part of many ecosystems. Determining bat species composition in an area is a critical first step in managing for this important resource. Little information exists concerning the bat species composition of Maryland’s Coastal Plain, which is located on the northern periphery of the geographic ranges of some bat species occurring in the southeastern United States. We conducted mist net surveys for bats at Assateague Island National Seashore, a barrier island on Maryland’s coast, in summer 2005, and summer and autumn 2006. In 2005, we captured 133 bats representing 3 species, including 2 big brown bats (Eptesicus fuscus), 129 eastern red bats (Lasiurus borealis), and 2 alleged Seminole bats (Lasiurus seminolus). In 2006, we captured a total of 60 eastern red bats in summer and autumn. We used long-term acoustic monitoring to document 3 additional bat species, including silver-haired bats (Lasionycteris noctivagans), hoary bats (Lasiurus cinereus), and eastern pipistrelles (Pipistrellus subflavus). We documented silver-haired bats during spring and autumn, probably as they were migrating through the area. Eastern red bats, and possibly hoary bats and big brown bats over winter at ASIS. Bat activity was inconsistently predicted by weather conditions depending on season. We used Anabat II bat detectors to monitor bat activity at 5 habitats or cover types during summer 2005 and 2006 and found that activity was higher in forests and at freshwater pools than at bayside marshes, dune/shrub zones, and beach areas. Low species diversity at Assateague Island National Seashore likely is attributable to long distances to hibernacula and low roost diversity, as forests are almost entirely comprised of loblolly pine (Pinus taeda).

Bat Inventory of Assateague Island National Seashore

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