Desert tortoise in the Mojave | Photo: Chris Clarke An environmental group will go to court to block plans to move more than 1,100 federally Threatened desert tortoises until scientists can examine how well the tortoises will do in their new homes, activists said Tuesday.
The Center for Biological Diversity, which has been watchdogging the desert tortoise issue for decades, says the U.S. Marine Corps and Bureau of Land Management havent adequately consulted with the U.S. Fish and Wildlife Service about the final destinations of the tortoises, which are slated to be moved out of the way of the Twentynine Palms Marine Corps Air Ground Combat Centers expanded tank training grounds near Lucerne Valley. That move will start as early as this month.
This proposed translocation is a disaster for the already at-risk desert tortoises in the west Mojave Desert, said Ileene Anderson, a senior scientist with the Center. This population has declined by 50 percent in the past 10 years. If the past is any guide, up to half of the tortoises won't survive this relocation, pushing these tortoises in the west Mojave closer to extinction.
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USFWS examined a draft of the plan in 2012 and found that the relocation as described back then wouldnt do damage to the protected species. But the Marine Corps has since released updates to that plan that offer more specific information about the places to which as many as 1,185 desert tortoises will be moved. Staff with the Center say the Marines and the Bureau of Land Management - which manages some of the relocation sites - should have come to the USFWS with that new information.
The Center says it intends to sue the BLM, USFWS and the U.S. Navy (which includes the U.S. Marine Corps) unless those agencies agree to conduct a scientific assessment of the tortoises fate based on that new information. That would almost certainly delay the relocation significantly. In the Centers formal Notice of Intent to Sue, attorneys Lisa Belenky and Jennifer Loda write:
[N]ew information, not available at the time of the 2012 consultation, shows that the impacts of the translocation may be far higher than previously anticipated, and may not serve to provide the anticipated avoidance or mitigation, or any avoidance or mitigation function for that matter.
If carried out, the Marines plan to move those tortoises from hundreds of square miles of tank training expansion area will be the largest single desert tortoise relocation in history. As many as 100 field biologists will be employed to move up to 900 adults from the expansion area. The remainder of the tortoises being moved are juveniles currently being held in so-called headstarting pens until theyre old enough to fend for themselves in the desert. Soft-shelled juvenile tortoises are particularly vulnerable to predation by ravens and other desert carnivores.
Desert tortoise | Photo: J W, some rights reserved
Moving desert tortoises to new territories is an intensely controversial practice. Thats in part because desert tortoises survival strategies rely on an intimate, years-long familiarity with their home territories, which generally cover a few square miles. Tortoises know where in their home territories they can easily seek shelter from predators or the elements; they also know where water will collect after a brief rain, and where their preferred plant foods grow in the greatest abundance.
Moving tortoises that might have lived for six or seven decades in their home ranges to new territories essentially strips the tortoises of most of their survival skills, especially in the first few years after being moved. The animals must use significantly more energy to find water, since they no longer know where the good drinking spots are. Long-distance moves, called translocation in the jargon, also brings tortoises into contact with new, potentially resentful tortoise neighbors, and conflicts among tortoises can increase the animals stress levels.
In 2008, the U.S. Army began to translocate desert tortoises from an area slated for expansion at Fort Irwin near Barstow. That project was halted in 2009 when biologists started estimating that around half the translocated tortoises had died. Some died because tortoises already living in the new habitat were carriers of an often-fatal respiratory disease; others were eaten by coyotes desperate for food in a drought year.
Defenders of translocation say that federal biologists have learned from the Armys mistakes, and that the Fort Irwin mortality rates were a bit of an anomaly. But the whole cencept of translocation of senisitive species has come under fire from some scientific quarters, and not just for tortoises. In a paper published last year in the journal Frontiers in Ecology and the Environment, the San Diego Zoos Jennifer Germano and six biologist colleagues suggested that translocation may often be a merely cosmetic form of mitigation:
Many countries have regulatory frameworks that cover such translocations. Legal requirements, driven in part by public perception and pressure, also provide the primary funding mechanism for such activities, requiring that developers relocate protected species from affected land. This raises the question of whether such animals are simply being spared a socially unacceptable death via bulldozer only to perish out of view at a release site.
We contend that mitigation-driven translocations, while well-financed, are often inappropriately executed, poorly documented, and unquestioningly used without regard to larger, more strategic conservation goals.
Complicating things further, the desert tortoises now living in the Twentynine Palms expansion area are genetically distinct from their near neighbors in the western Mojave, including some tortoises already living in places to which the expansion area tortoises will be moved. That
