By Mark Waite
A record of decision was signed last Friday approving the translocation of desert tortoises from the Desert Tortoise Conservation Center into native habitat in southern Nevada, including at Trout Canyon.
A record of decision signed by U.S. Bureau of Land Management Assistant Southern Nevada District Office Manager Erick Kurkowski states the BLM has determined the proposed action with the mitigation measures will cause no significant impact on the human environment and won’t require an environmental impact statement.
Healthy desert tortoises will be moved from the Desert Tortoise Conservation Center into the natural environment. The translocation will augment and assist recovering desert tortoise populations and provide monitoring and research opportunities, the finding states.
The fish and wildlife service hopes the mating of desert tortoises from the conservation center with the native population will lead to an increased population of the endangered species and increase the gene flow.
The final environmental assessment approved Friday addresses the initial translocation site in Trout Canyon, that site will be monitored to provide guidance for future sites.
“They plan to move 400 adults and 400 juveniles over the next year to Trout Canyon. It may not be all at one time but that’s the plan. The Trout Canyon area is 59,000 acres,” U.S. Fish and Wildlife Service spokesman Jeannie Stafford said.
Mitigation measures include following U.S. Fish and Wildlife Service protocol for site selection, disease testing, genetic testing, survey protocols, handling and monitoring techniques. Stafford said a couple of other potential sites include Coyote Springs, northeast of Las Vegas and Eldorado Valley, south of Boulder City.
The sites had to be below 5,500 feet elevation and capable of supporting desert tortoise habitat suitable for all life stages. The Trout Canyon site lies a few miles from Highway 160 at elevations from 3,400 to 5,500 feet.
The preferred sites should be within 46 miles of the Desert Tortoise Conservation Center, where desert tortoise populations are considered genetically similar. Locating tortoises in areas with fewer land use conflicts and depleted tortoise populations will put them at lower risk of mortality, according to the assessment. Highways nearby should be fenced and preferably four miles away.
The low number of resident tortoises within the Trout Canyon release site means there will need to be intensive health sampling of the resident population, the environmental assessment states. Only healthy tortoises will be released from the conservation center to prevent the spread of disease.
The translocations will avoid land for disposal in the Southern Nevada Public Land Management Act, major recreation areas, rights-of-way, solar energy zones, active mineral sites, dry lake beds and lands not managed by the BLM.
The finding of no significant impact FONSI states the Trout Canyon site meets all the criteria except it isn’t listed as contiguous high value habitat for desert tortoises. But it lies in a block of habitat that may be valuable for connecting tortoise populations. It also doesn’t meet criteria for land use conflicts, the FONSI states.
The western boundary of the Trout Canyon translocation site is the Clark-Nye County line, by Highway 160 on the south, by the west bank of Lovell Wash on the east side. The findings note about 19 miles of Highway 160 from Trout Canyon Road to Lovell Canyon Road have fencing to exclude the desert tortoise.
The environmental assessment states after the initial 800 tortoises are released, about 100 will be translocated annually over 10 years. Trout Canyon was previously selected as a release site in 2005, but not selected; however previous resource concerns have been resolved.
The Desert Tortoise Conservation Center has so many tortoises, a pick-up service to transport unwanted, captive tortoises has ended.
“We are thinking it’s pretty much filled to capacity. They don’t want to put any more tortoises out there if they can’t find a suitable location for them,” Stafford said.
Prior to its listing as an endangered species in 1990, desert tortoises could be kept as pets, the owners have been allowed to keep their offspring. But further collection of desert tortoises is prohibited. Pet owners may have a long-term commitment, Stafford said desert tortoises can live 50 years in the desert, while in captivity they can live much longer.
Most tortoises will be released into the wild in washes which may limit their dispersal. A group of them will be monitored with radio telemetry, providing opportunities to retrieve any that may wander onto Highway 160, all will have markings on them, the environmental assessment states.
A study group will be released in the 1997 mule burn area, where creosote bushes have resprouted, another outside the burn area.
“It is apparent that the local tortoise population in the Trout Canyon area has suffered a decline in the moderate past, warranting the use of population augmentation for further investigation,” the EA states. There is less chance of a health risk from the translocated tortoises due to the low number of native desert tortoises in the area.
BLM spokesman Kirsten Cannon said the release of the tortoises in Trout Canyon shouldn’t affect nearby development. The Trout Canyon turnoff is just over the Clark County line a few miles south of Pahrump.
“For each construction project there’s an individual, biological opinion that comes from the fish and wildlife service. This should have no impact on development, there’s the same mitigation fee, the same biological opinion that existed in the past, that will continue in the future,” Cannon said.
But Nye County Commissioner Butch Borasky was concerned. He wants fish and wildlife to construct a tortoise fence on Trout Canyon Road to prevent them migrating into Nye County.
“In the future it could cause us a great deal of pain if the tortoise migrate from the Clark County line to the Nye County line, which they do,” Borasky said. “It could hurt us in the future to the tune of millions of dollars should any of them migrate into our community, or our county, if anyone wants to build something there because it is an endangered species.”
U.S. Fish and Wildlife Service Desert Tortoise Recovery Coordinator Roy Averill-Murray didn’t think it could impact development nearby, which already has to undergo evaluation if it’s in tortoise habitat. He said the closest releases would be two miles from the county line, logistically chances are very few would cross into Nye County.
“The fact there’s a translocation in Trout Canyon in this area doesn’t add any additional restrictions or regulatory processes or anything else,” he said.
Pet tortoises, when placed back in the wild, display behavior consistent with wild tortoises, the EA states. The tortoises can travel 3.73 miles in the first year, particularly in the first two weeks.
“Because of the post-translocation movements exhibited by desert tortoises, potential also exists for desert tortoise mortality on roads during the initial period when translocated tortoises are establishing new home ranges,” the EA states.
The desert tortoise, Gopherus agassizii, was named an endangered species under an emergency rule in August 1989. Clark County developed a short-term habitat conservation plan, Nye County has yet to develop one.
Adopted tortoises have been housed at the Desert Tortoise Conservation Center, constructed in 1990 near Sloan, eventually resulting in a population of thousands. The San Diego Zoo, which currently operates the center, receives approximately 1,000 tortoises every year from the public in addition to the current occupancy of about 1,800.
In 1996, a Large Scale Translocation Site was opened on 26,200 acres near Jean. Over 15 years over 9,000 tortoises have been transferred from the Desert Tortoise Conservation Site to the Large Scale Translocation Site.
Desert tortoises spend much of their time underground and often use burrows. They are active from mid-March through October. They can adjust their metabolism to limited forage and water loss.