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29th Annual Meeting and Symposium of the
Desert Tortoise Council, February 20-23, 2004
Abstracts
Status of the Desert Tortoise in the Red Cliffs Desert Reserve
Ann M. McLuckie1, Richard A. Fridell1, Melinda
Bennion1 and Randy Radant2
1Utah Division of Wildlife Resources, 344 East Sunland Dr.
#8, St. George, Utah 84790
2Utah Division of Wildlife Resources, 1594 W. North Temple,
P.O. Box 146301, Salt Lake City, Utah 84114
The Upper Virgin River Recovery Unit, managed as the Red Cliffs Desert Reserve (Reserve), is located in southwest Utah, Washington County. The Reserve represents the northeastern extent of the desert tortoise's geographic distribution. The Reserve contains 38,787 acres of Mojave desert tortoise habitat and its primary goal is to maintain a stable or increasing tortoise population in perpetuity. It is considered a highly threatened population due to its proximity to urban growth and small size.
The Utah Division of Wildlife Resources has been intensively monitoring tortoises in the Reserve since 1998. In 2003, full-scale tortoise monitoring revealed a density estimate of 0.17 tortoises per ha (0.12-0.22) within Management Zone 3 of the Reserve and a density estimate of 0.17 (0.13-0.22) throughout the Reserve. Current estimates in 2003 show a 47% population decline within Zone 3 and a 41% decline throughout the Reserve since tortoises were regionally monitored in 1998. Both estimates show a biologically significant downward trend.
Several demographic parameters including shell remains, growth rates, and health assessments were observed as a byproduct of monitoring. The number of shell remains observed in 2003 increased dramatically. The majority of shell remains found were in areas with high relative tortoise densities. These shell remains showed no evidence of predation and died within one year. The status of tortoise translocation within Management Zone 4 as well as culvert monitoring will also be presented.
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