Despite resistance from environmental groups, the Bureau of Land Management will reopen a wide swath of the imperiled Sonoran desert tortoise’s habitat to cattle grazing on the Sonoran Desert National Monument.

The decision comes after a 2016 U.S. District Court ruling required the federal agency to reassess the impact of grazing on six allotments north of Interstate 8. The allotments make up more than half of the 496,000-acre monument.

Much of the land in those allotments has been identified by the Bureau of Land Management (BLM) as an important habitat for the Sonoran desert tortoise, which is designated by the state of Arizona as a species of “greatest conservation need” and protected by state law.

The desert-dwelling herbivore, native to Arizona, is primarily threatened by habitat degradation, according to Arizona Game and Fish Department. As global heating exacerbates long-running drought and fuels bigger and hotter wildfires in Arizona and across the West, the tortoise will face increasing challenges to its survival.

After years of petitioning from environmental groups, the US Fish and Wildlife Service has listed the species as a candidate for additional protection under the federal Endangered Species Act.

“When you layer on climate change and drought and the large numbers of fires we’ve had in the last ten years, the Sonoran Desert National Monument should really be a haven for wildlife and native plants,” said Cyndi Tuell, Arizona and New Mexico Director of the Western Watersheds Project, a conservation group focused on the western U.S.

The group brought the 2016 lawsuit against the BLM that resulted in the court ordering the agency to do further study on the impact of livestock grazing.

That renewed study resulted in the current plan, which the agency opened to public comment in July. The plan was approved last week and will allow the monument’s six livestock grazing allotments, all located north of Interstate 8, to be open for “responsible permitted livestock grazing,” according to the agency.

FIRST PROPOSAL:Feds want to reopen monument to cattle grazing

“How many people or livestock permittees are going to be benefiting from this decision to allow cows to continue to trample this monument?” Tuell said. “I don’t know why they’ve decided to lean so heavily on a handful of permittees to graze in a desert landscape at the expense of species like the Sonoran desert tortoise, bighorn sheep, saguaro and cultural resources. They didn’t explain how they decided a little bit of money being made by a handful of people would outweigh all the damage that’s going to happen.”

Six grazing allotments that overlap with the monument’s northern area have remained open to grazing, though for the past decade they have been essentially empty of cattle.

The BLM has not authorized grazing on five out of six of the allotments since 2012, in part because the land that the allotments encompass “do not consistently produce enough forage to sustain a livestock operation, but may briefly produce unusual volumes of forage to accommodate livestock grazing,” according to the agency.

Two of the six allotments still have active grazing permits, but the BLM last authorized limited grazing in 2015 on just one allotment.

The approved plan sets a range for grazing from ephemeral use only to a maximum of 4,232 perennially authorized animal month units across all six of the allotments. An animal month unit is the amount of forage needed to sustain one cow and her calf for a month.

“The approved plan amendment is a culmination of research, analysis and public input that has led to a decision that meets the multiple-use mission of the BLM and addresses the court remand,” said BLM Phoenix District Manager Leon Thomas. “The amended resource management plan allows for balanced resource management today and allows land managers the flexibility of decision-making based on conditions on the ground in the future.”

The plan states that the extent of grazing will be set when grazing is actually implemented and will be based on resource monitoring data as well as public input.

“They’ve given a total number of AUMs, but we don’t know exactly where those are going to be, we don’t know if it’ll be year-long,” Tuell said. “They’re deferring all those decisions to down the road. They’ve punted the football and the game may be over for the public.”

Allotments classified as ephemeral or perennial-ephemeral could be authorized to graze the “unusual volumes of forage” available during ephemeral seasons, which generally follow the winter and spring rains, BLM spokesperson Mariela Castaneda wrote in response to emailed questions from The Republic.

“The availability of ephemeral forage (annual plant species) is dependent on the timing and amount of precipitation as well as the serviceable area livestock waters provide,” Castaneda wrote. “Ephemeral seasons can produce up to one thousand pounds of annual forage per acre, of which grazing efficiency and wildlife needs are considered prior to recommending a level of livestock use.”

The Sonoran desert tortoise relies on such bursts in forage to survive in its arid homeland. The desert-adapted creature gets almost all of its water from the plants it eats, typically foraging during monsoon blooms between July and October. It will get most of its food for the entire year during this period, according to the Arizona Game and Fish Department.

“The few times of years we do get rain, they’re planning to dump cows out there,” Tuell said. “That food is also food for the Sonoran desert tortoise.”

The final plan found that livestock grazing on the six allotments would have “no significant impact” on natural or cultural resources.

The agency received nearly 9,000 comments from environmental organizations and individuals who largely opposed allowing livestock grazing on the monument. The agency determined that none of the comments “indicated any substantial dispute in the scientific community” over the impact of the proposed managed grazing.  

The BLM analysis cites peer-reviewed journal articles published in 2008 or prior in its reference section.

“This clearly indicates the agency is not, in fact, sufficiently updating its understanding of the effects of livestock grazing,” Tuell said. “We provided much more recent scientific research that the agency continues to ignore in this decision-making process, in violation of the requirement to use the best available science.”

Most research has shown that livestock grazing, particularly when poorly managed, is detrimental to ecosystems with limited forage and the sensitive biocrusts that make up desert soil. Carefully managed grazing can be compatible with some areas in the arid southwest, some rangeland experts say.

A century of overgrazing in the desert southwest has left lingering impacts on desert landscapes and the creatures that inhabit them. Nonnative plants and decreased forage continue to plague many desert ecosystems.

In the Sonoran Desert National Monument, studies have shown similarities in diets among tortoises, cattle, and feral burros. A 1994 study found that “on landscapes where enhancing forage conditions for desert tortoises is a goal, a conservative approach is ensuring that tortoises do not have to alter their preferred foraging activities because nonnative animals are present.”

There has been inconsistent monitoring of plant communities and desert tortoise health in the years since. 

The grazing allotments are also on the ancestral lands of the O’odham, Yavapai Apache, Cocopah, and Hohokam peoples, and include many historic and cultural sites.

In June, the Tohono O’odham tribe told the BLM it opposed allowing livestock grazing on the monument due to potential damage to fragile archeological sites. The monument is a portion of the traditional use area by the tribe and contains evidence of use from Tohono O’odham ancestors.

“It’s definitely disappointing,” Tuell said. “The court in 2016 agreed that BLM hadn’t done their job and it seems like they’ve slightly reduced the number of livestock they’ll potentially have out there, but they still haven’t done their job protecting the natural and cultural resources.”

Erin Stone covers the environment for The Arizona Republic and azcentral.com. Send her story tips and ideas at [email protected] and follow her on Twitter @Erstone7.

Environmental coverage on azcentral.com and in The Arizona Republic is supported by a grant from the Nina Mason Pulliam Charitable Trust. Follow The Republic environmental reporting team at environment.azcentral.com and @azcenvironment on Facebook, Twitter and Instagram.

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