Every spring and fall, the Nellis Natural Resources Program surveys Nellis Air Force Base, Nev., and the Nevada Test and Training Range for signs of Mojave desert tortoises.
The search consists of systematically hiking through desert tortoise habitats, recording desert tortoises, their burrows, scat, and other tortoise signs.
“The desert tortoise create burrows, a tunnel structure that is used by many different species of wildlife,” said Kristen McCarty, Center for Environmental Management of Military Lands wildlife biologist, “so the desert tortoise is an indicator to the over-all health of the diverse species in the area.”
The desert tortoise spends up to 95 percent of its life underground, and can live in a variety of habitats from desert flats to rocky foothills and canyons. They can be found from sea-level to 3,500 feet in elevation.
“We are out looking for the tortoises so that we can make future recommendations for development of those areas.” McCarty said, “If we find an area that has a high population of tortoises, we might suggest to the Air Force that they refrain from developing in that area, or put in additional protections [such as] adding fences to keep tortoises out of roads or areas they might be affected by humans.”
During active tortoise season, spanning April through May and September through October, NNRP’s team surveys weekly for signs of activity on Nellis AFB and the NTTR.
“The Air Force utilizes this survey data to minimize potential impacts to the species. We also actively plan for conservation opportunities such as habitat restoration,” said Olivia Baez, 99th Civil Engineer Squadron natural resource program manager.
The Mojave desert tortoise was listed as a threatened species under state law in 1989 and under federal law in 1990 due to the severe decline in population numbers.
“By doing these surveys we can analyze data from past years and determine if the tortoise population is declining and by what metrics.” McCarty said, “Generally, range-wide, the population decreased 32 percent between 2004 and 2014.”
Several factors have led to the decline in the population numbers of the desert tortoise. Developing areas, roads, ravens, and coyotes are all threats to the health of the species.
“There are many things that we can do to help protect the desert tortoise population.” McCarty said, “Never remove a tortoise from the wild or release a pet tortoise into the wild. As they can spread disease to wild tortoises. When traveling desert roads, mind your speed if you are near undeveloped areas. If you have been parked for a long period of time in those areas, check under your car before driving. And lastly, do not litter in the desert. Ravens and coyotes are attracted to the food that humans leave out and grow their population size. Ravens have increased their population by 700 percent since the 1970’s due to human interaction.”
As recently as the mid-century, tortoises were a common sight in the Mojave region. Today they are rarely seen and in some areas they have vanished completely.
“Much can be done to protect this threatened species,” McCarty said, “so I would say my job is very rewarding.”