TUCSON, Ariz.— The Center for Biological Diversity and Maricopa Audubon Society filed a formal notice of their intent to sue the U.S. Bureau of Land Management today for failing to protect endangered species in the San Pedro Riparian National Conservation Area from rampant trespass livestock grazing.

The notice includes more than 90 separate complaints of trespass cattle in the area. It says the Bureau of Land Management has violated the terms of a 2022 agreement resulting from a 2021 lawsuit seeking to protect the conservation area and the rare plants and animals that depend on it.

“The San Pedro and its endangered plants and animals don’t stand a chance against the cows,” said Robin Silver, a Center cofounder “We’ve been fighting for decades to save the San Pedro and its fragile ecosystem. Sadly, the Bureau of Land Management is too apathetic to protect the river from abusive neighboring ranchers, whose cows are ravaging streamside habitats and pushing these species closer to extinction.”

The notice seeks to force the bureau to comply with its agreement to repair and maintain fencing along the San Pedro River and remove trespass cattle that are devastating the riparian area. The cattle are jeopardizing the endangered Huachuca water umbel and harming critical habitat for yellow-billed cuckoos and Northern Mexican garter snakes.

The San Pedro Riparian National Conservation Area was the nation’s first, created by Congress in 1988. It includes more than 46 miles of the San Pedro and Babocomari rivers and nearly 55,000 acres of riparian areas and uplands. It is home to four of the rarest habitat types in the Southwest: cottonwood/willow forests, marshlands, grasslands and mesquite bosques.

More than 400 birds, 50 species of reptiles and amphibians, and 80 species of mammals are found in the conservation area, making it a world-renowned biodiversity hotspot.

“For years the BLM has turned a blind eye as cows feast upon and trample the water umbel and these beautiful wetlands,” said Charles Babbitt, conservation chair of the Maricopa Audubon Society. “The plant’s health is an indication of how the whole ecosystem is doing. Sadly, the San Pedro National Conservation Area is on life support and its BLM caretakers are out to lunch.”

In addition to trespass cattle in the conservation area’s wetlands, the threats to the endangered Huachuca water umbel include drought, climate change and declining groundwater levels from development and over-pumping.

Other endangered species in the area include Southwestern willow flycatchers, ocelots, jaguars, desert pupfish, Gila topminnows and Arizona eryngo.

In a May 2018 letter to the Bureau of Land Management, 21 scientists urged the agency to exclude livestock grazing from the conservation area. Allowing livestock grazing here jeopardizes its many aquatic and riparian species and the area’s critically important role as an ecological reference site, they wrote.

The area is the traditional territory of the Chiricahua Apache, Opata, O’odham, Hohokam and Sobaipuri people.