Desert Tortoise Conservation Heating Up
The Mojave desert tortoise is a threatened species living right here in the Mojave Desert, just a stone’s throw from the San Diego Zoo Institute for Conservation Research. Aside from their amazing adaptations for living in the desert, they are a keystone species that other animals depend upon for safety and protection.
While desert tortoises spend 95 percent of their lives in burrows that they dig deep in the soil, these burrows also serve to protect other species from predators and harsh weather conditions. In addition, tortoises disperse seeds from the native plants they eat, and as they digest, they repopulate the desert using the seeds from those plants, thereby providing food and shade to other desert animals when the plants grow. It is no understatement to say that without desert tortoises in the desert, we have no desert.
Sadly, wild populations of Mojave desert tortoises are estimated to have declined as much as 90 percent in the past 20 years; it is estimated that there are only about 150,000 wild Mojave desert tortoises remaining in critical habitat in the wild.
Although desert tortoises can live to be 50 to 100 years old, they have low reproductive success, so few eggs hatch each year in the wild, and of those that do, not many hatchlings survive to adulthood. With many threats to their survival, including predators, habitat destruction, disease, and the illegal pet trade, until recently, little hope remained that these animals that have been on the planet for 200 million years would persist through another century.
But today, we have a renewed hope for the success and continuation of Mojave desert tortoises.
In March 2009, the San Diego Zoo Institute for Conservation Research, as a member of the Conservation Centers for Species Survival (C2S2), began a partnership to operate the Desert Tortoise Conservation Center (DTCC) along with the U.S. Fish and Wildlife Service (FWS), the Bureau of Land Management (BLM), and the Nevada Department of Wildlife (NDOW).
The DTCC is the only facility of its kind, serving as a drop-off location for unwanted pet desert tortoises and a future hub for interdisciplinary research to help save not only Mojave desert tortoises but their native habitat. We are the only authorized organization permitted to take in these animals, rehabilitate them and legally release them to the wild through a structured research program to ensure their success.
One of the biggest issues we face at the DTCC is the pet desert tortoise problem, which is fueled by the backyard breeding of pet desert tortoises. There are thousands of desert tortoises being kept as pets in the Las Vegas Valley while wild populations are suffering from diminishing numbers every year. To help address this problem, the San Diego Zoo and its partners are in the process of changing the role of the Center from that of a transfer-and-holding facility to one that will support range-wide recovery efforts for the desert tortoise through conservation research, participation in on-the-ground recovery actions, training of biologists, and public education specifically aimed at reducing the numbers of pet desert tortoises, while substantially increasing the numbers of wild tortoises living in the Mojave Desert.
To that end, this spring we released 30 desert tortoises to a protected habitat in southern Nevada, and all of them were fitted with radiotransmitters prior to release. Two full-time staff track these tortoises on a daily basis and record not only their locations, but their behaviors and activities. We selected the best habitat available for the release and anticipate great success, in part due to the extensive forage available that resulted from our exceptional winter rains. These tortoises will be followed for two years, and the data we collect will help to direct our future releases. With this exciting new research, we are taking the first step in learning how to recover wild desert tortoise populations.