Thesis Title

Activities Within a Myotine Bat Community With Emphasis on the Endangered Indiana Bat, Myotis Sodalis

Date of Graduation

Fall 2003

Degree

Master of Science in Biology

Department

Biology

Committee Chair

Lynn Robbins

Subject Categories

Biology

Abstract

The steady decline of the endangered Indiana bat (Myotis sodalis) and its interactions with other congeners are not adequately understood. A study area in northeast Missouri was identified during a survey in 2000 and found to host one of the largest M. sodalis maternity populations ever found, as well as M. septentrionalis and M. lucifugus. I recorded 144 detector nights yielding 46,588 bat echolocation calls using Anabat II bat detectors. A nested sampling design was used with five habitat types which include upland and lowland sites within each habitat. Calls were identified to species using a linear discriminate function analysis and a library of known calls. The three species of Myotis each showed unique habitat preferences evident by a significant two-way interaction between species and habitat. M. sodalis showed the highest levels of activity and foraging events among the three species and had a significant main effect of habitat. Forest corridors had the highest levels of M. sodalis activity, although standing freshwater sources were most important for foraging during the post-lactation period. Habitat usage also was varied between M. septentrionalis, which favored riparian corridors and forest corridors, and M. lucifugus which favored standing fresh-water sources. There was no significant main effect of habitat for either of these two species, however. M. lucifugus was the least recorded species and the only one with significant effect on activity from moon phase. Time of night was a significant main effect for both M. sodalis and M. septentrionalis. While M. sodalis showed increasing activity with a peak towards the end of the night, M. septentrionalis were active early with declining activity as the night progressed. The idea that M. sodalis and other myotines may be considered as a single group is not supported by the data in this study showing differences in habitat use and temporal activity distributions.

Copyright

© Matthew N Miller

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