Study of relocated desert tortoises reveals a surprise

May 25, 2017 by Laura Otto, University of Wisconsin - Milwaukee
Female desert tortoises adjusted well to relocation, but the males did not, a study has found. Credit: University of Wisconsin - Milwaukee

Results of a study on the relocation of a community of desert tortoises in California has unveiled a mystery: When moved only a short distance from their habitat, the females in the group assimilated to their new location and reproduced normally – but not the transported males.

The study originated in 2008 with a planned expansion of Fort Irwin National Training Center in the Mojave Desert. But the expansion area included a swath of prime habitat for the endangered . So the U.S. Department of Defense funded relocation of the tortoises to an area adjacent to the base that is less than 10 miles south of their previous home.

The Smithsonian Institute's National Zoo and Conservation Biology Institute has completed parentage analysis after the relocation and has found that none of the transported males had sired any offspring.

In contrast, all the moved females and the resident tortoises had adjusted well and reproduced.

"These results were really surprising," said Emily Latch, a UWM associate professor of biological sciences and a co-author of a paper published May 24 in the journal Biological Conservation. "We fully expected that after several years, all tortoises would be reproducing at 'regular' levels. Our radio telemetry data indicated that translocated males were in the vicinity of females, and so had access to mates."

Translocation is common strategy, used to increase genetic diversity among populations and move threatened animals in the case of habitat loss.

Latch, who worked on the early stages of project as a post-doctoral researcher with the Smithsonian, has also worked on translocation projects involving species of wild turkeys, mule deer, bison, bighorn sheep, river otters and fishers.

These findings, she said, suggest that for some species, translocation may not be as effective a tool to rescue populations at risk as previously thought.

Kevin Mulder, a graduate student at the Smithsonian Conservation Biology Institute and first author on the paper, said more research is necessary to identify what may have happened.

Explore further: California tortoises died trying to reproduce during drought

More information: Kevin P. Mulder et al. No paternal genetic integration in desert tortoises (Gopherus agassizii) following translocation into an existing population, Biological Conservation (2017). DOI: 10.1016/j.biocon.2017.04.030

Related Stories

Wind turbines affect behavior of desert tortoise predators

May 4, 2017

How a wind energy facility is designed can influence the behavior of animal predators and their prey, according to a recent study published in the Journal of Wildlife Management by researchers at the University of California, ...

New methods can protect animals during relocation

February 2, 2015

As Arizona continues to see development into formerly rural areas, additional research is emerging to help protect wildlife species. Because the state is home to a dozen rattlesnake species, understanding best practices for ...

Recommended for you

Genome duplication drives evolution of species

September 25, 2018

Many wild and cultivated plants arise through the combination of two species. The genome of these so-called polyploid species often consists of a quadruple set of chromosomes—a double set for each parental species—and ...

Some female termites can reproduce without males

September 24, 2018

Populations of the termite species Glyptotermes nakajimai can form successful, reproducing colonies in absence of males, according to a study published in the open access journal BMC Biology.

Photosynthesis discovery could help next-gen biotechnologies

September 24, 2018

Researchers from The University of Queensland (UQ) and the University of Münster (WWU) have purified and visualized the 'Cyclic Electron Flow' (CEF) supercomplex, a critical part of the photosynthetic machinery in all plants, ...

How fruits got their eye-catching colors

September 24, 2018

Red plums. Green melons. Purple figs. Ripe fruits come in an array of greens, yellows, oranges, browns, reds and purples. Scientists say they have new evidence that plants owe their rainbow of fruit colors to the different ...

Custom circuits for living cells

September 24, 2018

A team of Caltech researchers has developed a biological toolkit of proteins that can be assembled together in different ways, like Legos, to program new behaviors in cells. As a proof-of-concept, they designed and constructed ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.