EDWARDS AIR FORCE BASE, California -- The base Environmental Management section, in partnership with San Diego Zoo Global, successfully released 116 juvenile tortoises on Edwards Air Force Base, California, recently.
The release of the tortoises was a result of the Head Start program which aims to protect newborn and juvenile tortoises from predators and other threats in the wild said Wes King, a Biological Scientist with the 412th Civil Engineer Group’s Environmental Management section.
“It gives them a ‘head start’ on life,” he said. “Because of habitat loss, predation, diseases, and other issues, desert tortoise populations have seen a rapid decline in the recent decades.”
The Head Start program began in earnest in 2002 after experts decided that “head-starting” was a potential way to help augment the desert tortoise population in the area.
To further strengthen these efforts, Edwards Environmental Management began a partnership with SDZG and the United States Geological Survey in 2017. That partnership was further strengthened in October 2020 after the announcement of Military Interdepartmental Purchase Request (MIPR) agreement.
“USGS and SDZG will be working together to accomplish the program requirements and make this a successful endeavor for desert tortoise recovery,” King explained. “Since the onset of this program, over 500 tortoises have been hatched and raised in the Edwards’ head-starting pens and almost 300 of those have been released on base, on nine separate occasions.”
After their release, the tortoises are tracked regularly to collect data on their condition and determine if they are alive or not. The data helps to understand the success of the head-starting methods he explained.
The tortoises' head start on life begins at one of five main pens on Edwards. Each pen is almost 3,000 square feet and provides space for numerous juveniles, natural vegetation, rocks and burrows for shelter and for rest including brumation; a hibernation-like state for reptiles during winter months.
“There are also numerous, smaller, isolation pens for temporarily isolating new females. This is to ensure they are disease free before introduction into the main pens,” King added.
A number of other factors have contributed to the decline of the tortoise population in the Mojave Desert. Besides disease, other factors include loss of habitat due to invasive plant species and also human encroachment which has seen an increase of a natural predator.
“The common raven has followed humans into the Mojave Desert because we provide a significant amount of food for the common raven through our waste,” Kind said. “By drawing these predatory species into the desert tortoise’s range, they have found and learned that juvenile tortoises are able to be preyed upon with little risk.”
As a Federal agency, the Air Force is required by law to protect plants and animals listed on the Federal Endangered Species Act, which includes the desert tortoise, King explained.
“As good stewards of our natural resources, we are responsible to ensure this and other species are here for future generations. The health of an ecosystem can in part be measured by the health of the individual species that make up that ecosystem,” he said. “The rapid decline of the desert tortoise population in recent decades is a sign of problems that, if not remedied, will result in loss of this and many other local species.”