Population size and contaminant exposure of bats using caves on Fort Hood Military Base /
Seasonal cave usage patterns were determined in an effort to understand the ecology of a bat colony at Shell Mountain Bat Cave in Fort Hood, Texas. Exit counts were conducted one night each month for 13 consecutive months to estimate the population and determine seasonal patterns. This cave was us...
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| Format: | Thesis eBook |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
2001.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Summary: | Seasonal cave usage patterns were determined in an effort to understand the ecology of a bat colony at Shell Mountain Bat Cave in Fort Hood, Texas. Exit counts were conducted one night each month for 13 consecutive months to estimate the population and determine seasonal patterns. This cave was used as a maternity roost by a colony of cave myotis (myotis velifer) from March through October. Total colony size varies from month to month, becoming zero when bats leave during the winter. Old guano from two abandoned caves, Egypt and Tippet, on Fort Hood, and new guano from Shell Mountain was analyzed. Organochlorine residues showed higher levels of total chlordanes, endrin, dieldrin, mirex, p,p'-DDE, and o,p'-DDT in Egypt and Tippet caves; organophosphates showed higher amounts in the Shell Mountain guano. Organophosphates have never before been found in bat guano, and so what effects, if any, these amounts may indicate on the health of the colony are unknown. Some metals were also found in higher amounts in guano from Egypt and Tippet caves. Residue concentrations of organochlorines and metals in guano and carcasses collected from the three caves are low and probably of no concern. Comparisons among spring and fall guano smaples from Shell Mountain suggest that HCB, total chlordanes, dieldrin, endrin, endosulfan II, p,p'-DDE, and o,p'-DDT are accumulated while the bats are at Fort Hood. Lindane appears to be the only chemical that increases while the bats are at Fort Hood. Organochlorines found in carcasses tended to show smallest amounts in a lactating female and largest amounts in nursing juveniles. |
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| Item Description: | "Major subject: Wildlife and Fisheries Sciences". Vita. |
| Physical Description: | ix, 102 leaves : illustrations, maps ; 28 cm. Also available online. Issued also on microfiche from Lange Micrographics. |
| Bibliography: | Includes bibliographical references (leaves 33-36). |