Date of Award

Fall 2008

Document Type

Legacy Thesis

Degree Name

Master of Science in Coastal Marine and Wetland Studies

Department

Coastal and Marine Systems Science

College

College of Science

First Advisor

Sharon L. Gilman

Second Advisor

Wendy R. Hood

Third Advisor

Kevin S. Godwin

Additional Advisors

Keith R. Walters

Abstract

Bats comprise approximately one quarter of all mammal species. Little work has been conducted on coastal islands with regard to bat ecology and habitat use. The Lower Coastal Plain (LCP) of South Carolina is home to possibly 12 species of bats. Bats in the Southeastern U.S. exhibit similarities in their call characteristics including but not limited to the visual representation of their calls (i.e. sonograms). Often, researchers base identification solely on the sonogram of a recorded call without considering other facets of call structure. Identification of bats inhabiting the coastal plain by acoustic monitoring is difficult and the results may be unreliable. Reference sonograms of known bat species were analyzed and characteristics including high and low frequencies, duration, and high to low frequency, slope, and bandwidth were compiled to set up a data library for each species. Ratios were developed for the characteristics listed above. Ratios along with visual characteristics of species specific sonograms were used to identify bat calls recorded in the field. Species identified via the method also were the same species that were captured using mist nets and harp traps on Spring Island, SC. Captured bats were identified by visual and metric evaluation of high frequency call features. Bat richness on Spring Island was assessed during the summer of 2007 using both capture and acoustic monitoring techniques. Bat calls along two general edge habitat types (pine and hardwood) were recorded to determine if bat activity differed significantly between edge habitats. Pine edge habitats on Spring Island are less vegetatively complex than hardwood edge habitats and bat activity was predicted to be greater along pine edges than hardwood edges. Larger bats may have greater difficulty foraging and flying in dense and cluttered vegetation than smaller bat species, and navigation through such areas may be more energetically costly than navigating through less dense and open-air areas. Insect dry mass along edge habitats was collected to determine if bat activity was dependent upon insect prey availability. Six species of bats were identified on Spring Island through capture and acoustic monitoring. Bat activity (based on the number of recorded bat calls) did not differ significantly between the 2 edge types. Data did not support the prediction that the number of recorded bat calls would be greater along pine edges than recorded along hardwood edges. Bat activity along hardwood edge habitats was greater than expected suggesting that canopy-free areas like the fields on Spring Island may be important areas for bats. Unlike many other studies, bat activity was not dependent upon insect mass (g).

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