Does vegetation cover affect the rate of capture of ground-active lizards in pitfall traps?
Christine A. SchlesingerFaculty of Education, Health and Science, Charles Darwin University, Alice Springs, NT 0871, Australia. Address for correspondence: PO Box 795, Alice Springs, NT 0871, Australia. Email: christine.schlesinger@cdu.edu.au
Wildlife Research 34(5) 359-365 https://doi.org/10.1071/WR06141
Submitted: 20 October 2006 Accepted: 3 July 2007 Published: 6 September 2007
Abstract
Pitfall traps are commonly used to capture terrestrial vertebrates, but it is not known whether differences in vegetation structure affect the efficiency of these traps. Studies that investigate the effects of fire, grazing or vegetation rehabilitation on faunal populations usually compare sites that differ in vegetation structure and the validity of using pitfall traps to sample populations under these circumstances is open to question. This study tests whether vegetation structure affects the rate at which lizards are captured in pitfall traps by cutting ground vegetation in a controlled experiment conducted in field enclosures. The study was undertaken in an area of mulga (Acacia aneura) shrubland in central Australia. Ground cover, consisting of grasses and forbs, was reduced from ~27% to 10% in treatment enclosures. These levels of cover correspond broadly to the range of ground covers encountered in this habitat, including areas with high and low levels of grazing. No difference was detected in the rate at which lizards were captured in enclosures where grass was cut compared with the control enclosures or rates of capture before grass was cut. These results indicate that pitfall trapping is a valid technique for comparing lizard populations in arid mulga shrublands within the range of vegetation covers used in this study, including areas that are subject to different levels of grazing.
Acknowledgements
I gratefully acknowledge CSIRO Sustainable Ecosystems for providing office space and logistic support throughout the field work stage of this project. I thank Kevin Jones, Tim Acres and Stephanie Creed who assisted with installation and dismantling of the field enclosures. Craig James, Steve Morton and Keith Christian gave valuable advice during the study and comments on an earlier version of the manuscript. Gary Prior kindly gave permission to work on Hamilton Downs Station. I thank Michael Craig for providing access to unpublished data. The project was carried out under a Conservation Commission of the Northern Territory Licence for Scientific Research Permit No. A/93/18, A/94/18 and A/95/21 and Northern Territory University Animal Experimentation Ethics Committee project approval code 930416. Funding was provided by a CSIRO/University collaborative research grant and the author was supported by an Australian Postgraduate Research Award.
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