PARENT SESSION

Conservation 3 -- Session Chair: Patrick Kelly-- University Center, Kate Buchanan Room

DNA CONTENT VARIATION IN HISPID COTTON RATS (SIGMODON HISPIDUS) FROM ABANDONED COLLIERY STRIP MINES. Kimberly A. Hays, Maria A. Harrington and Karen McBee. Department of Zoology and Collection of Vertebrates, Oklahoma State University, Stillwater, OK, USA.

ABSTRACT- Colliery strip mining reached its peak in Oklahoma in the 1940?s. By the 1970?s many of these mines had been abandoned and have never been reclaimed. As a by-product of the strip mining, soils contaminated with heavy metals were brought to the surface. For example, surface lead levels have been measured at more than 500 g/g at mine sites. Approximately, 12,000 ha of unreclaimed surface mines in Oklahoma have revegetated naturally and support small mammal communities. Surface soils at Marler mine, located in eastern Oklahoma (Okmulgee Co.), contain levels of Cu, Pb, Zn and Cd that are significantly higher than unmined reference sites. To determine the impact of heavy metal exposure on small mammals at orphaned mine sites we live-trapped hispid cotton rats (Sigmodon hispidus) from Marler mine. Cotton rats also were collected from a nearby unmined reference site, Eufaula Wildlife Management Area, (Okmulgee Co.) and from a remote reference site, Lake Carl Blackwell, in north central Oklahoma (Payne Co.). One of the known effects of exposure to environmental heavy metals is chromosomal damage. We used flow cytometry to quantify DNA damage as the coefficient of variation (CV) around the mean nuclear DNA content for 20 individuals per site. We hypothesized that S. hispidus trapped from Marler mine would have higher coefficients of variation (i.e. higher levels of DNA damage) compared to animals from the two reference sites; however, a Kruskal-Wallis k sample test yielded no significant difference in DNA content variation among the three sites.

KEY WORDS: DNA damage, ecotoxicology, flow cytometry