28th Annual Meeting and Symposium of the
Desert Tortoise Council, February 21-23, 2003
Abstracts

Reproduction in a Desert Tortoise (Gopherus agassizii) Population on the Beaver Dam Slope, Washington County, Utah

Ann M. McLuckie and Rick A. Fridell
Utah Division of Wildlife Resources, 344 East Sunland Dr. #8, St. George, Utah 84790

Life history information including clutch size, clutch frequency, annual fecundity, egg dimensions, and hatchling success was collected in 1989 from the Beaver Dam Slope desert tortoise population, in southwestern Utah. The mean clutch size for both first and second clutches was 5.2 ± 0.50 eggs (n=16). Mean clutch size of the first and second clutches did not significantly differ. Mean clutch frequency was 1.33 ± 0.14 clutches per reproductive female (n=12). Carapace length was significantly correlated with mean clutch size and clutch frequency. Annual fecundity of tortoises ranged from 3 to 18 eggs. Mean annual fecundity was 7.0 ± 1.16 eggs and was significantly correlated with carapace length (n=12). Carapace length was significantly correlated with egg width but not egg length. Reproductive tortoises had a smaller home range than non-reproducing tortoises; however, this difference was not significant. Compared with other Mojave desert tortoise reproductive studies, the Beaver Dam Slope population had a lower clutch frequency and percentage of reproducing females. In the past decade, the Beaver Dam Slope has experienced population declines due primarily to disease and habitat degradation and alteration.