 |
 |
 |
 |
 |
 |
 |
25th Annual Meeting and Symposium of the
Desert Tortoise Council, April 21-24, 2000
Abstracts
Major Scientific Contributions from the Desert Tortoise Research Natural Area: 1973-1999
Kristin H. Berry1 and Michael J. Connor2
1U.S. Geological Survey, Biological
Resources Division, 6221 Box Springs Boulevard, Riverside, California,
92507
2Desert Tortoise Preserve Committee, 4067
Mission Inn Ave, Riverside, CA 92501
The Desert Tortoise Research Natural Area (DTRNA) has provided critical information for understanding desert tortoise (Gopherus agassizii) ecology, physiology, health, and behavior. Since 1973, research projects conducted at the DTRNA have played an important role in identifying major issues for the desert tortoise such as: tracking population dynamics and the catastrophic declines; discovery of upper respiratory tract disease; quantifying physiological and reproductive adaptations to drought and abundant precipitation; establishing plasma and biochemical reference ranges; developing protocols for field handling techniques; identifying forage patterns and preferences; documenting the impacts of raven predation on juvenile tortoises; and describing the protective effects of preserve fencing in regards to livestock grazing and off-road vehicles. For the past 26 years, the approach has been for integrative scientific research with each project drawing on the others.
The DTRNA has provided biologists and land managers with valuable lessons for design and management of reserves for the recovery of tortoise populations in the Mojave and Colorado deserts. Management issues such as disease, raven predation, invasion and establishment of alien plant species and encroaching urban interfaces are at a landscape scale. The existing hogwire fencing and management do not effectively protect tortoises as individuals or as a population because of landscape-scale problems. Therefore management issues must be addressed at a landscape scale for recovery to be successful. During the next century, the DTRNA, as well as many other parks and reserves, will face challenges of disease, predators, alien species, and urban, recreational, and industrial developments.