Roost Site Selection By Indiana Bats Myotis Sodalis And Comparison Of Foraging Habitat Selection By Morphologically Similar Bat Species In Bottomland Hardwood Ecosystems

Author : Sandra Rancourt
Publisher :
ISBN 13 :
Total Pages : 110 pages
Book Rating : 4.:/5 (455 download)

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Download or read book Maternity Roost Site Selection of Big Brown Bats and Long-eared Myotis in the Channeled Scablands of Northeastern Washington written by Sandra Rancourt and published by . This book was released on 2000 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bat conservation is often hindered by a lack of geographic-specific knowledge of the bat community and the characteristics of roost sites used by reproductive females. I assessed the composition of the bat community and examined the use and characteristics of roosts selected by reproductive female big brown bats (Eptesicusfuscus) and long- eared myotis (Myotis evotis) in the Channeled Scablands of northeastern Washington. This area contains a high diversity of potential roost types (snag and tree cavities and rock and human-made structures) known to be used by both species of bats. I trapped 536 bats representing 10 species during 1996-97 using mist nets and harp traps. Radio-telemetry was used to locate 38 and 35 roosts of reproductive female big brown bats and long-eared myotis, respectively. Both species switched roosts frequently. Habitat variables were measured at three levels; the roost site, a random site near the roost, and a random site at a landscape level. Ninety-five percent (n = 36) of the big brown bat roosts were in natural tree cavities. Twenty-eight roosts were in ponderosa pine (Pinus ponderosa) and eight in aspen (Populus tremuloides). Dead tops of live pine trees were used significantly more as roosts than pine snags by big brown bats. Although there were significantly more roost trees>30 cm in diameter and taller than 12m than what was available, they were not necessarily the tallest tree in the stand. A significantly greater proportion of big brown bat roosts were found in open pine, aspen and mixed-aspen pine forests and less in grasslands and closed pine than expected. Obstruction of roost trees was not different than randomly selected trees. Big brown bat roost sites were not significantly different in forest structure than random sites. All but one of the 35 long-eared myotis roost sites were found in crevices in small basalt rock formations. Long-eared myotis roosts were in open habitats close to the edge of closed forest stands. Both species selected roosts in an area with a greater proportion of aspen and open ponderosa pine habitat. Forest restoration strategies should protect both large diameter snags but also existing dead top trees and should maintain natural population levels of biological agents that create dead tops. Restoration of historic open conditions in ponderosa pine will provide improved habitat for both big brown bats and long-eared myotis. Caution must be exercised in making generalizations about roost selection of individual bat species, given regional differences found in this and other studies.