Tor­toises in the Mojave Desert (CA)

A Head Start for an En­dan­gered Species

Snowbirds & RV Travelers - - Contents - By Phillip Gomez

The cryp­tic lives of tor­toises—spent pre­dom­i­nantly in un­der­ground bur­rows— and the many years that it takes for them to reach sex­ual ma­tu­rity and to re­pro­duce, have made it dif­fi­cult for con­ser­va­tion bi­ol­o­gists to con­duct field stud­ies.

So, the Na­tional Park Service, to­gether with the U.S. Fish and Wildlife Service, Chevron Corp., Moly­corp Inc., and two universities have part­nered to cre­ate a work­ing fa­cil­ity to try to gain a bet­ter un­der­stand­ing of tor­toise be­hav­ior that af­fects their sur­vival. The Ivan­pah Desert Re­search Fa­cil­ity is staffed by a small team of fac­ulty and Ph.D. can­di­dates from the Sa­van­nah River Ecol­ogy Lab­o­ra­tory of the Univer­sity of Ge­or­gia and from the Univer­sity of Cal­i­for­nia, Davis. For this long-term re­search project, ju­ve­nile tor­toises are be­ing “re­cruited” over a 20-year pe­riod and nur­tured in this fa­cil­ity un­til they are ca­pa­ble of join­ing the Ivan­pah Val­ley’s pop­u­la­tion with a rea­son­able chance for sur­vival. The idea for this experiment in wildlife man­age­ment, en­ti­tled Desert Tor­toise Ju­ve­nile Sur­vivor­ship at Mojave Na­tional Pre­serve—or Head Start to re­searchers—is sim­i­lar to the prin­ci­ple un­der­ly­ing chil­dren’s nurs­ery school­ing: giv­ing kids a head start in life.

In the case of the tor­toise, the goal is to gain time for the rep­tile’s shell to de­velop and har­den to make the young rep­tiles safe from preda­tors. Adult tor­toises with hard­ened shells have few preda­tors, but ju­ve­niles are ex­tremely vul­ner­a­ble for the first four or five years of life.

“It’s all about the pre­da­tion,” says De­bra Hugh­son, the Pre­serve’s chief of sci­ence and re­source stew­ard­ship. “The pur­pose of Head Start is to al­low them to sur­vive.” How many tor­toises are there in the Pre­serve? “No­body knows ex­actly, but only a small per­cent­age make it to adult­hood,” Hugh­son said.

This, cou­pled with the late ma­tu­rity of the tor­toise, which can take 18 to 20 years to reach breed­ing age, makes for long odds in the game of sur­vival in the desert.

Once nu­mer­ous in the Mojave, the desert tor­toise be­gan ex­pe­ri­enc­ing loss of nat­u­ral habi­tat from a va­ri­ety of sources by the late 1980s:

Tor­toise of the Mojave

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