SREL Reprint #2821

Gopher tortoise burrow surveys: External characteristics, burrow cameras, and truth

Rebecca B. Smith1, Tracey D. Tuberville2, Angy L. Chambers3, Kris M. Herpich4, and Joan E. Berish5

1Dynamac Corporation, Mail Code DYN-1, Kennedy Space Center, Florida, 32899, USA
2Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, South Carolina, 29802, USA
345th Space Wing Environmental Flight, 45CES/CEVT, Patrick Air Force Base, Florida, 32925, USA
4Comprehensive Health Services, CHS-22, Kennedy Space Center, Florida, 32899, USA
5Florida Fish and Wildlife Conservation Commission, 4005 S. Main St., Gainesville, Florida, 32601, USA

Abstract: The gopher tortoise (Gopherus polyphemus) occupies the southeastern Coastal Plain of the United States where it digs burrows in upland habitats. Two burrow survey techniques commonly used to estimate tortoise population size (classification of burrows based on external characteristics and surveying burrow contents with a burrow camera) were tested to determine accuracy and subjectivity among researchers. Accuracy of both methods was verified by excavating the burrows to determine if tortoises were present. Classification of burrows based on external characteristics was found to be highly subjective, related to the researchers' prior gopher tortoise experience, and unrelated to familiarity with the landscape. Burrow camera surveys were accurate, but should be used with caution as mistakes can be costly. Inadequacies in the currently accepted burrow survey methods are discussed and suggestions for improvements are made.

Keywords: burrow classification; burrow occupancy; burrows; gopher tortoise; Gopherus polyphemus; protected species; surveying errors; survey methods.

SREL Reprint #2821

Smith, R. B., T. D. Tuberville, A. L. Chambers, K. M. Herpich, and J. E. Berish. 2005. Gopher tortoise burrow surveys: External characteristics, burrow cameras, and truth. Applied Herpetology 2:161-170.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).