Relocating and Augmenting Desert Tortoise Populations

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As resource managers balance the needs of humans and wildlife, WERC’s Dr. Berry provides the necessary science to inform decisions on shared lands. Visit the “Science” tab to delve into specific projects.

The U.S. Fish and Wildlife Service, Department of Defense, and California Department of Fish and Wildlife are among the government agencies tasked with conserving and recovering populations of wildlife listed as threatened or endangered under Federal and state Endangered Species Acts. Dr. Berry’s research provides insight into the different factors that positively or negatively affect Agassiz’s threated desert tortoise.

Mitigation and Augmentation Related to Desert Tortoises

The National Training Center (NTC), Fort Irwin, has populations of the desert tortoise (Gopherus agassizii), a State- and Federally listed threatened species. When Fort Irwin expanded its boundaries, the USGS Western Ecological Research Center worked with the agency to relocate several hundred Agassiz’s desert tortoises to adjacent lands managed by the U.S. Bureau of Land Management.  The effects of translocation, coupled with new and emerging diseases, require detailed studies. Dr. Kristin Berry studied the epidemiology of upper respiratory tract disease in tortoises prior to translocation and is continuing to monitor health of translocated adult tortoises. Her studies include the short- and long-term effects of translocation on adult desert tortoises in the central Mojave Desert. This project includes evaluations of health, disease, movements, development of home ranges, habitat use, survival, and vulnerabilities to death.

 

Health Conditions of “Head-Started” Desert Tortoises

Agassiz’s desert tortoise populations in the Mojave Desert are declining. To inform management and conservation efforts by the Department of Defense and other government agencies, Dr. Berry is studying the health, condition, and survival of juvenile tortoises in “headstart pens” on Edwards Air Force Base, and survival after translocation. Headstart pens provide shelter from most of the desert’s predators and harsh weather, offering a chance for the tortoises to grow in relative safety. One essential question is the numbers (and densities) of tortoises that can be supported in pens. To determine behavior and long-term survival, Dr. Berry and team have fitted juveniles with radio transmitters and are monitoring behavior, condition, and survival after release.