27th Annual Meeting and Symposium of the
Desert Tortoise Council, March 22-24, 2002
Abstracts

Desert Tortoise Ecological Research at Saguaro National Park, Arizona

Don E. Swann¹, Cecil R. Schwalbe², Eric C. Stitt³, Taylor A. Edwards⁴, Roy C. Averill-Murray⁵, Todd Esque⁶, Jay D. Johnson^7
1Saguaro National Park, 3693 South Old Spanish Trail, Tucson, AZ 85730; 
²U.S. Geological Survey, Sonoran Desert Field Station, Tucson AZ 85721; 
³Wildlife and Fisheries Science, University of Arizona, 125 Biological Sciences East, Tucson, AZ 85721; 
⁴Wildlife and Fisheries Science, University of Arizona,125 Biological Sciences East, Tucson, AZ 85721; 
⁵Arizona Game and Fish Department, 2221 North Greenway Rd., Phoenix, AZ 85023; 
⁶U.S. Geological Survey, Las Vegas Field Station, Las Vegas, NV, 89119; 
⁷DVM, University Animal Hospital, 2500 S Hardy Drive, Tempe, AZ 85282

Saguaro National Park has become a focal point for research on the Sonoran Desert population of the desert tortoise, and several collaborative studies are underway that build on previous survey efforts and research on fire effects. To assess the impact of urban development on tortoises we are using radiotelemetry to determine home-range sizes and tortoise movement patterns before and after development adjacent to the park. We are using distance sampling to determine changes in abundance over time, and genetic techniques to assess the effects of habitat fragmentation. We are also studying reproductive ecology and aspects of hatchling ecology such as timing of hatchling emergence, size distribution of neonates, and after-emergence movement patterns. Finally, we are assessing the significance of positive tests for Mycoplasma in this near-urban park tortoise population. Continued research by scientists in this multi-agency partnership is planned to increase our knowledge of how urban development and other environmental factors affect long-term survival of individual tortoises and tortoise populations.