Indiana bat (myotis sodalis) summer roost tree selection and habitat use in the Champlain Valley of Vermont

Palm, Jessana
Peter Palmiotto, PhD
Department of Environmental Studies
Recent surveys by federal and state agency personnel have established the presence of the federally endangered Indiana bat (Myotis sodalist) in the Champlain Valley of Vermont. The lack of clear understanding of this species' habitat requirements in this region reduces the ability to successfully protect it. The purpose of the project was to determine whether Indiana bats select roost trees based on external tree characteristics and whether surrounding habitat characteristics also influence habitat use. During the summer of 2002, three female bats were tracked to 11 roost trees, including two maternity roost trees, using radiotelemetry. At these trees, and an additional nine known roost tress, roost tress and habitat characteristics were documented. Similar data was also collected at 22 randomly selected sites to compare roost trees used by Indiana bats to potential roost trees in the study area. Roost trees used by Indiana bats were discovered to be larger in diameter and more exposed to solar radiation than potential roost tress. All 13 interior roost trees were dominant or codominant in the canopy. Roost sites had greater snag basal area than potential roost sites and were comparable to snag basal area levels reported for old-growth forest studies in northeastern United States. Shagbark hickory basal area and stem density was also greater at roost sites that at potential roost sites. Based on the results of this study conservation and forest management planning should focus on retaining large live shagbark hickory trees and large diameter snags to ensure adequate roost habitat in the region. Forest management techniques aimed at supporting Indiana bats should focus on high snag basal area, particularly where shagbark hickories are rare and/or maternity roosts have been documented.

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