The Bureau of Land Management (BLM) has called protection of a desert tortoise corridor north of Las Vegas “imperative” to the species’ recovery. Yet it is considering a massive solar project in the middle of it. Western Watersheds Project and Basin and Range Watch have formally protested the agency’s final environmental review of the proposed Bonanza Solar Project.
The BLM is siting a 5,133-acre photovoltaic and lithium battery project on public lands in high-quality, intact Mojave desert tortoise habitat, 70 miles north of Las Vegas. The area, on the north side of the Spring Mountains, has a high density of diverse cactus species such as pencil cholla, cottontop cactus, Parish club-cholla, and beavertail cactus, as well as tall flowering Mojave yuccas. An estimated 150,000 cacti and yuccas live in the desert ecosystem here.
The broad alluvial fan was a former grazing allotment, which BLM closed to livestock in order to conserve wildlife values.
A crucial tortoise connectivity corridor here connects mountain ranges and harbors an intact, contiguous, high-quality tortoise habitat block. The Bonanza Solar Project is sited in the middle of this connection between Critical Habitat units. The solar project would fragment intact habitat and degrade vegetation communities and soils needed by the tortoise population for survival.
“The project proponents claim they can use mitigation measures to complete an industrial-scale solar farm without taking away from the functionality of the corridor and health of the tortoise habitat and populations,” said Laura Cunningham, California Director at Western Watersheds Project. “We maintain that this cannot be successfully done and the project cannot proceed without serious harm to the critically-imperiled tortoise.”
Conservationists petitioned the BLM to designate the Cactus Springs Area of Critical Environmental Concern (ACEC) here in 2022, to protect this high-value public land tortoise habitat. The original 2012 Western Solar Plan designated this tortoise connectivity area as a solar exclusion zone due to its high tortoise habitat values on public lands.
After the Southern Nevada District Office of BLM received the nomination, the proposed solar development was increased in acreage by the BLM. This corridor is mentioned in the 2011 Mojave Desert Tortoise Recovery Plan, which states that the “Eastern Mojave Recovery Unit the Spring Mountains, which provided much of the separation between the former Northeastern Mojave and Eastern Mojave recovery units, narrowly channel gene flow through habitat corridors to the north and south, connecting this recovery unit to the Northeastern Mojave Recovery Unit.”
BLM stated that recovery of the federally threatened Mojave desert tortoise is reliant on not only preserving protected areas, such as Critical Habitat Units, also maintaining connectivity between those protected areas to preserve genetic connectivity. Because desert tortoises are not migratory species, ensuring they have adequate habitat to maintain sufficient populations across the landscape is one of the most critical recovery criteria.
Yet instead of designating this ACEC to protect these resources under the Federal Land and Policy Management Act, the Nevada state office of BLM went on to consider solar developments right in the middle of this connectivity corridor.
“The construction of Bonanza Solar Project would degrade habitat, block large areas of connectivity, and jeopardize tortoise viability here,” said Cunningham.
BLM now is trying to punt the designation of this ACEC to a vague future time, and rely on experimental new temporary mitigation measures to act as a placeholder for ACEC protections while simultaneously allowing the construction of a large-scale solar energy project in the connectivity corridor.
Kevin Emmerich, Co-founder of Basin and Range Watch said the Interior Department has been pushing solar development on important desert tortoise habitat since 2009.
“While perfectly viable alternatives for solar energy exist on rooftops and degraded lands, the industry developers want to be as close to transmission infrastructure as possible even if important species are compromised,” he said. “The BLM works overtime to enable infrastructure projects on public lands but makes excuses when they reject long-term conservation proposals that could maintain imperiled species for years.”
Project mitigation relies heavily on translocating desert tortoises, but the BLM says in the Final Environmental Impact Statement that “translocated Mojave desert tortoise experience high mortality rates, over 50% mortality has been documented in the first three years following translocation, primarily from predation.”
Permanent disturbance to Mojave desert tortoise habitat would occur. The solar energy developer proposed that the solar project could be constructed in this high-quality tortoise habitat, and then the tortoises could be allowed back in the solar fields after construction and during operation, if all vegetation was not removed.
BLM discussed connectivity in the Final Environmental Impact Statement emphasizing that under the Endangered Species Act it has a commitment to preserving connectivity corridors of functional tortoise habitat, saying, “protection of the corridor of Mojave desert tortoise habitat north of the Spring Mountains is imperative to allow for the continued connectivity of the Eastern Mojave Recovery Unit and the Northeastern Mojave Recovery Unit. Protection of this area is also imperative to connect Critical Habitat Units in California to Critical Habitat Units in Nevada, Arizona, and Utah. Connected habitat is crucial for Mojave desert tortoise recovery.”
Yet in the end, BLM decided on “interim temporary mitigation measures” that claim to allow functional tortoise habitat to co-exist with an industrial solar project. These include reducing the project footprint, reducing acreages of grading and soil removal, using more drive and crush construction methods, and maintaining 65% of the vegetation density within the solar array fields.
The developer would attempt to avoid knocking over or driving on tens of thousands of Mojave yuccas and cactus plants in the project site, and when this was not possible the yuccas and cacti would be salvaged and an attempt made to replant them and water them to keep them alive. The Right-of-Way for the solar project would be for 50 years.
BLM found the ACEC nomination worthy, yet chose to defer designation to the future, while using unproven “temporary management” to try to stave off “irreparable damage” to relevant and important values of the public land here. The joint protest asks BLM to designate the Cactus Springs Area of Critical Environmental Concern, as nominated, and to deny approval of this solar project to truly conserve this tortoise habitat.
Laura Cunningham is the California Director for Western Watersheds Project and a biologist and naturalist with decades of experience studying desert ecosystems, wildlife, and public lands across the American West.
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