TUCSON, Ariz.— The Center for Biological Diversity sent a notice today to the Bureau of Land Management and U.S. Fish and Wildlife Service of its intent to sue the agencies for habitually allowing unlawful cattle grazing to damage 70 miles of river designated as critical habitat for endangered birds, fish and other species in southeastern Arizona.

“Federal agencies have spent years pretending that cow-trashed streams aren’t a problem, leaving endangered species without a fighting chance at survival,” said Chris Bugbee, Southwest conservation advocate at the Center. “These animals and plants are barely hanging on. It’s time for the agencies that are supposed to protect them to finally do their job.”

Today’s notice cites six years of surveys documenting chronic grazing damage, threatening 11 endangered species across the BLM’s Gila District. It challenges the biological opinion authorizing grazing in the area, including the Gila Box Riparian National Conservation Area, which Congress established to safeguard stream ecosystems and biodiversity.

Cows devastate stream and riparian habitats by trampling banks, stripping vegetation to bare soil, blocking tree regeneration and polluting water with feces, urine, sediment and cattle carcasses. Most damage documented in field surveys occurred in streamside areas where grazing is prohibited.

Endangered species named in the notice are the yellow-billed cuckoo, southwestern willow flycatcher, spikedace, loach minnow, razorback sucker, Gila chub, Gila topminnow, Chiricahua leopard frog, northern Mexican and narrow-headed garter snakes, and acuña cactus.

After a Center lawsuit in 2021, the Fish and Wildlife Service agreed to develop a new biological opinion under the Endangered Species Act for livestock grazing in the Gila District. But field surveys showed more widespread cattle damage occurred in 2024. Surveys in 2025 also documented extensive damage to endangered species habitat from unauthorized grazing.

“Arizona’s rare desert rivers and streams should be teeming with life, with dense vegetation, clean water and thriving animal populations,” said Bugbee. “That’s what endangered species need, and that’s what people visiting their public lands want. Instead they’re ravaged feedlots. If federal agencies keep cows out, nature will recover.”

Arizona’s riparian areas cover less than 1% of the state’s land but support up to 75% of its wildlife, making them among the most critical and imperiled ecosystems in the region. Most low-elevation riparian forests have been destroyed by human activity, including livestock grazing. The cottonwood-willow riparian forest, which once lined rivers across the Southwest, is now the rarest forest type in North America.

Livestock grazing is a primary cause of species endangerment, biodiversity decline and riparian ecosystem degradation in the U.S. Southwest. Removal of livestock from riparian areas is critical to curbing the extinction crisis regionally.