Boyd Deep Canyon Desert Research Center

30 May, 10 AM - 02 Jun, 01 AM

Research on the federally threatened desert tortoise has been conducted in several locations in Joshua Tree National Park (JOTR). In 1978 John Barrow marked 51 tortoises in the Pinto Basin in a one square mile area now known as the Barrow Plot. Subsequent research was conducted by Jerry Freilich in the same area during the early and mid-1990s. Later (1997-1999), the applicant (Jeff Lovich) marked tortoises at the Barrow Plot and other locations (including Indian Cove) as part of a study of the reproductive ecology of female desert tortoises. During the latter study a significant number of female tortoises were killed by predators, possibly coyotes that switched prey after a drought. The general perception is that tortoise densities decreased at the Barrow Plot through time, a possible result of warming and drying trends in climate. Research by a different researcher, Cameron Barrows, suggests that tortoise distribution in the Sonoran Desert portion of JOTR will decline up to 88% with a +2 C increase in temperature and a -50 mm decrease in precipitation. Is the perceived decline at the Barrow Plot confirmation of Barrow?s model prediction? The long-term data available from the Barrow Plot provide an unparalleled opportunity to assess changes in demography and survivorship of tortoises at this study site and perhaps the first demonstration of Barrow?s prediction.

Visit #28417 @Boyd Deep Canyon Desert Research Center

Approved

Under Project # 25210 | Research

Assessing the long-term survival of Agassiz's desert tortoise at a long-term study plot in Joshua Tree National Park

professional - US Geological Survey

Reservation Members(s)

Group of 2 Research Assistant (non-student/faculty/postdoc) May 30 - Jun 2, 2012 (4 days)

Reserve Resources(s) | Create Invoice