Desert Tortoises Step Closer to the Wild

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Can you find the desert tortoise in this burrow?

We recently completed our inventory of all the tortoises on site at the San Diego Zoo Desert Tortoise Conservation Center (DTCC). It took us two full active tortoise seasons, but we did it! (See Pam’s previous post, Counting Tortoises). Although this task has occupied nearly all of our time, we have somehow also been able to move healthy tortoises into our newly designated 20-acre translocation enclosure. Healthy, ELISA-negative tortoises (see post Tortoise Science: Cooler than You Think about ELISA testing) that have remained free of upper respiratory tract disease (URTD) symptoms for at least 30 days will be moved to the translocation enclosure (we call it a “pen”), the final step before being relocated into the wild next spring!

We had to make sure that the translocation pen could accommodate the number of tortoises we wanted to put in it, so our four seasonal research assistants had the task of adding burrows to provide the tortoises with protection from the heat and cold and installing a water delivery system to this pen. Each burrow takes an hour or more for one person to dig, but we have successfully added 50 burrows to this pen over the course of 2 months while still conducting inventory!

We now have over 100 healthy tortoises waiting to be relocated to a U.S. Fish and Wildlife Service-approved translocation site here in southern Nevada! We plan to put radio transmitters and GPS data loggers on the healthy tortoises prior to the long-anticipated release in the spring of 2011. A team of experienced telemetry technicians will follow the signal from these transmitters, allowing us to track and study the movements and habit use of these animals.

Why is translocation into the wild so important? Wild populations of Mojave desert tortoises have reportedly declined by approximately 90 percent in the past 30 years; it is estimated that there are only about 150,000 wild Mojave desert tortoises remaining in critical habitat. The desert tortoise is a keystone species, meaning that it plays a critical role in its environment. How? Desert tortoise burrows serve to protect other desert species from predators and harsh weather conditions, and they disperse seeds from the native plants that they eat, repopulating the desert ecosystem with them.

Our mission is to play a significant role in the conservation of the Mojave Desert, including the recovery of the desert tortoise and its habitat. Through all of our work, including translocation, we are well on our way to fulfilling our mission!

Pamela Cicoria is a research associate at the San Diego Zoo Desert Tortoise Conservation Center.