The desert tortoise has roamed the Mojave for millions of years—even before the region was a desert. Over millennia, the tortoise has adapted to thrive in one of the planet’s harshest environments.
“The desert tortoise is a true arid land denizen,” says Sophie Parker, Ph.D., senior scientist for The Nature Conservancy. “It survives in the desert by growing slowly and digging burrows to escape the heat.”
One thing it can’t handle is rapid change. Human activity in the desert has caused the tortoise to be placed on the California and Federal Endangered Species List. Its status is threatened, just one notch below endangered. How the renewable energy industry grows within the Mojave Desert could determine the future of the desert tortoise—and hundreds of other native species.
A threatened species is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range.
Underneath the barren surface, desert soils support a miniature garden of lichen, algae, moss and microorganisms. This biological soil crust can take decades to form—and some individual plants have been around for thousands of years. So, once industry moves into an area and disturbs the soil, the ecosystem will never be the same.
“It can take decades to restore that land—if it’s even possible to restore it at all,” says Erica Brand, director of The Nature Conservancy’s California Energy Program. “So once it’s converted, it will stay that way for a very long time, if not forever.”
A full moon rising over one of the mitigation properties in Lancaster, California.
© Dave Lauridsen
To help California move toward a clean energy future while also protecting this unique desert ecosystem, The Nature Conservancy completed an in-depth ecoregional assessment in 2010. The goal was to analyze the conservation value of the entire Mojave Desert—all 32 million acres. Previous assessments had focused on critical conservation areas, known as portfolio sites, but a complete assessment to characterize the value of land within the ecoregion had never been done before.
“We wanted a better understanding of the threats to biodiversity,” says Dr. Parker. “And we wanted to develop a long-term vision of what conservation success would look like.”
Using information about the presence of plants and animals across the landscape, as well as data on roads and properties that had been previously disturbed or developed, the assessment placed land into four categories, each with a different conservation value. “Ecologically core” and “intact” areas were a priority to protect while “moderately degraded” and “highly converted” land could be developed with a lower environmental impact.
One factor the study considered was the location of desert seeps and springs. Underneath the desert’s surface are groundwater aquifers containing water that predates the last ice age. Many unique plants and animals, some of which are endemic to the Mojave, depend on this water, which bubbles to the surface in seeps and springs. But today, a lot of this water also is pumped and used by people—and some of it goes toward the operation and maintenance of solar facilities.
An aquifer is a geological formation that contains or conducts groundwater, often feeding wells and springs.
“If too much water is taken from this system, the recharge may not be high enough to replace the groundwater,” Dr. Parker says. “If the aquifer becomes overdrafted, you can have land subsidence, where the land actually falls in and constricts the aquifers. That means there could be less space to store water in the future.”
While the assessment found that 86 percent of the Mojave retains high conservation value, there were also hundreds of thousands of acres that had already been disturbed.
The takeaway for policymakers was clear: It’s possible to meet aggressive renewable energy goals using land with lower conservation value—leaving the desert connected and intact from the Salton Sea to Death Valley.
“Because we did our analysis before the planning processes were fully underway, we have the ability to help guide policy and decision-making,” Dr. Parker says.
This influence can be seen in the Desert Renewable Energy Conservation Plan (DRECP). The first phase, which was approved by the Bureau of Land Management in September, will guide land use decisions for 10.8 million acres of public land. It sets aside 388,000 acres, more than 600 square miles, as renewable energy development focus areas—and 6.5 million acres for conservation. The designations were informed by The Conservancy’s ecological assessments done in the Sonoran and Mojave Deserts.
The DRECP also safeguards the desert’s groundwater by protecting the rare places where groundwater surfaces as springs, seeps and wetlands. It promises a network of connected, intact lands and water sources, stitching together already protected parks and preserves like Joshua Tree, Death Valley and the Mojave National Preserve.
“The DRECP ensures we address one issue without creating another,” Brand says. “It’s a science-based, collaborative road map for siting renewable energy on public lands in places that will have less ecological impact—so we can address the causes of climate change while still protecting the desert.”