Marines Relocate Desert Tortoises
MARINE CORPS AIR GROUND COMBAT CENTER TWENTYNINE PALMS, Calif. --
The southern Mojave Desert is known by most as a serene landscape, freckled with lizards, coyotes and jackrabbits, as well as a cornucopia of other wildlife and desert vegetation.
But starting April 8, 2017, the landscape was temporarily adorned with trucks, biologists and a helicopter, all in support of one being: the desert tortoise.
The translocation, in accordance with a U.S. Fish and Wildlife Service-signed biological opinion, serves as a negotiated mitigation to support the mandated land expansion, which will enable the installation to conduct large-scale exercise training with up to a Marine Expeditionary Brigade-sized force.
During this two-week long translocation, approximately 1,100 desert tortoises will be located, assessed for health concerns or disease, and carefully translocated to their new homes. Animals deemed too small for translocation will be admitted to the Combat Center’s Tortoise Research and Captive Rearing Site where they will be safeguarded until they are large enough to adequately fend off predation.
During this initial translocation effort, Natural Resources and Environmental Affairs anticipates being able to locate and move approximately 93 percent of the total population from the pre-identified areas. Additionally they will conduct post-translocation clearance surveys for approximately five years. These surveys will require NREA to periodically scout for any remaining desert tortoises.
Handling With Care
“This effort has entailed almost four years’ worth of surveys, with the environmental analysis dating back to 2008,” said Marine Corps Lt. Col. Timothy Pochop, the director of natural resources and environmental affairs at Twentynine Palms. “These surveys included health assessments, identifying all the animals [within the translocation] areas, placing radio transmitters on [the tortoises] and determining suitable locations in which to distribute them, to ensure survivorship and assimilation,” Pochop said.
According to Brian Henen, the base ecologist at Twentynine Palms, the translocation is much more involved than just picking up the tortoises and placing them in a different location. The physical translocation involves locating and identifying the animals by radio transmitters affixed to them during the initial analysis, then delivering them in individual bins via helicopter to one of five pre-selected recipient sites. Each tortoise has been paired up with a specific location, nearly to the square meter, that meets rigorous criteria.
“The factors that went into selecting the recipient sites were based on several things,” Henen said. “The first is what we think best represents the social structure from where they started, the second is the geographical characteristics of where they come from and the third is the temperature when we move them. The animals are being moved now because the temperatures are not too hot or cold, which gives them an adequate amount of time to find a burrow which ensures assimilation and survivorship.”
According to Henen, there are benefits to taking factors like social structure and geographical location into consideration. If there is a group of animals in a certain area, some of them more than likely know each other. When they are relocated in a similar orientation they will be somewhat familiar with the animals they’re encountering at the new site, reducing some of the stresses on the tortoise that come with being in a new area. The same concept can be applied when closely matching the geographical characteristics of the tortoises’ previous homes. The more similarities there are between the recipient sites and the tortoises’ previous home, the less stress will be placed on the animal from being in an unfamiliar place.
The Marine Corps and the U.S. Fish and Wildlife Service have coordinated extensively on natural resource management measures with added emphasis and focus on the desert tortoise. The translocation plan was submitted to USFWS for consideration, and the Marine Corps initiated the actions to fulfill their commitment to the USFWS and the desert tortoise species.
“We are working with a team of highly-qualified biologists, some of which have been studying desert tortoises for close to 40 years,” Henen said. “They were approved by the U.S. Fish and Wildlife Service, which is really helpful in getting things done. It also allows a fair degree of trust because we know these biologists are qualified.”
This is the largest translocation that the Marine Corps has ever conducted. However, successful translocation has taken place in the past. In 2006 the installation translocated 17 adult tortoises to support construction of Range 220.
“There was a [urban operations] facility being designed on the base to facilitate training,” Henen said. “Due to the relatively large size of the facility, we consulted with the U.S. Fish and Wildlife Service and received a specific biological opinion that instructed us to move the tortoises out of the way. There were 17 tortoises moved with radio transmitters and then they were radio tracked at least once a month for three years. The most impressive and important result of that translocation was that there was 98 percent annual survivorship.”
For this translocation, the installation is using procedures from the previous one as well as expanding on their post-translocation monitoring efforts.
Guardians of the Tortoises
Although the installation has invested a lot of hard work and time in the desert tortoise, they know their work doesn’t end there. In addition to the ground work that was laid in preparation to move the tortoises, there is also a 30-year post-translocation monitoring plan for the animals that the Combat Center will adhere to.
“As part of this move, we will monitor the translocatees, the residents and a group of animals close by that we’ll use as a control group,” Henen said. “The idea behind that is to try to understand how well the translocatees do, how well the animals that are already there do and how those two compare to a nearby site that’s not impacted by the translocation.
“During the first five to 10 years, we will have 675 animals that we are tracking via radio almost every week during the active season and monthly during the winter in order to monitor their health, survivorship and some reproductive status,” Henen continued. “After that initial time frame we’ll narrow it down to 50 animals in each of the groups but those first years will be the most critical time to figure out how well the tortoises are doing and how well they settle. We want to make sure the techniques we’re using, when it comes to moving these animals, are viable ones.”
Although there is only a specific group of animals who will be tracked via transmitters, there will be population-level monitoring of the all translocatees in the recipient and control sites over the 30-year period.
In addition to this translocation effort, the Combat Center created the Tortoise Research and Captive Rearing Site which is a long-term assessment of how to protect nests, hatchlings and juveniles until they grow resilient enough to endure the harsh physical environment, resist most predation by common ravens and coyotes, and mature to fully-functional adults that produce offspring to enhance the existing populations.
Over the first nine years of headstarting, the Combat Center has raised 475 juveniles, generated annual survivorships of 96 percent, compared to 40 percent in the wild, and released their first cohort of 35 nine-year-old juveniles to the wild. The release and monitoring of juveniles is the next major phase in the installation’s headstart commitment to support the recovery of the desert tortoise.
“Every contractor, civilian employee and Marine in training is required to get a natural resources brief upon arrival to the Combat Center,” Pochop said. “The brief talks a lot about the tortoise and how they should conduct themselves if they come in to contact with the animal.”
Excellence in Stewardship
For their work with protecting and preserving the tortoise population, the Combat Center was recognized by the Secretary of the Navy.
“In 2015 we received the Secretary of the Navy Environmental Award for our efforts in natural resource conservation as an installation,” Pochop said. “In 2016, Dr. Brian Henen received the award as an individual for the conservation efforts that he has been responsible for.”
Whether training Marines to remain the nation’s premier fighting force, providing facilities to accommodate the needs of its patrons, or preserving and protecting the population of the desert tortoise, the Combat Center remains dedicated to meeting every facet of its mission.
“I work with caring people, Marines and civilians, most of whom acknowledge that we need to protect our environment for quality of our habitat because that influences our quality of life,” Henen said. “We want to do the right thing and I think that in many ways, we’re in a good position because we’re able to work in an atmosphere that encourages training as well as conservation.”
(Editor’s Note: As the Marine Corps’ premier service-level, combined arms training venue, the Combat Center’s mission is to enhance the combat readiness of the operating forces and support the Corps’ responsibility to national security. The Department of Defense and the Corps consider the lands on which they train to be part of the public trust and remain steadfast in maintaining an unwavering commitment to serve as good stewards of the environment. In 2006 the Marine Corps’ adopted new specifications for large-scale training exercises at the Combat Center. These scenarios combine the movement of infantry battalions with aircraft support and live fire. In the past, the Marine Corps did not possess a venue adequate enough to support this type of training and had to instead rely on classroom instruction and simulation, which provided unrealistic and limited practical experience for command, control and maneuver.)