Home range and movement of desert tortoises Gopherus agassizii in the Mojave Desert of California, USA

Abstract

Radio telemetry of 29 desert tortoises Gopherus agassizii in 2000 and 60 in 2001 at 4 sites in the Mojave Desert of California, USA, revealed that males had larger home ranges and moved greater distances than females, but that tortoises at sites with more rainfall did not always have larger home ranges or move greater distances. The Ivanpah Valley received more rainfall than the Fort Irwin area, Superior Valley, and Fremont, but differences between home range size and rainfall were not consistent. Within the Ivanpah Valley, the plot at the highest elevation received more rainfall than the lower plots. However, within the Ivanpah Valley, tortoises at the 3 locations did not differ in home range and movement. In the wetter year ( Males moved farther per day than females in both years. In 2001, female tortoises in the Ivanpah Valley used more burrows than tortoises at Fremont and Superior, but similar numbers as tortoises at Fort Irwin. There was no mortality of tortoises in 2000 and a 5% mortality in 2001.