LOS ANGELES— The Center for Biological Diversity sued the U.S. Bureau of Land Management today to protect highly imperiled Amargosa voles from unmanaged recreational use within their federally protected critical habitat. The voles’ small range is limited to dense bulrush marshes near a popular hot spring in the Mojave Desert outside Tecopa, California.

“Amargosa voles are on the brink of extinction, but federal officials are looking the other way while people party around the clock in these little animals’ only home,” said Patrick Donnelly, Great Basin director at the Center and a local resident. “Many visitors to this hot spring have an anything-goes mentality, and without thoughtful management their activities threaten the voles’ continued existence.”

Amargosa voles are mouselike mammals, among the most endangered small mammals in the country. Their numbers have fallen as low as a few dozen in recent years, and current estimates are that just a couple hundred remain.

An eight-year monitoring project in the voles’ habitat near the hot springs has revealed unsustainable recreational use. Unauthorized off-road vehicles, unattended campfires, off-leash dogs, unauthorized camping, litter, and a lack of bathroom facilities have led to severe degradation of the animals’ habitat.

Today’s lawsuit, filed in U.S. District Court in Los Angeles, says the BLM is violating the Endangered Species Act by failing to prevent degradation of that habitat. The vole was listed as endangered under California law in 1980, and in 1984 the U.S. Fish and Wildlife Service designated critical habitat for the vole after protecting it under the federal Act.

The voles have been the subject of intense conservation efforts over the past decade as scientists and wildlife managers have fought to keep them from going extinct. A captive-breeding program, habitat restoration, and creation of a lifeboat population helped start the voles on a path to recovery.

Amargosa voles live most of their lives in a very small home range of about one-quarter of an acre. They have been known to “surf” rare flash-flood waters, traveling long distances between suitable habitat patches. The marsh created by the hot spring is the voles’ stronghold; at times it has held as much as 90% of the global population of the rare creatures. Recent studies have concluded that the subspecies has an 85% chance of going extinct by 2026 if nothing is done to protect its habitat.

“If people are going to keep descending on the Amargosa vole’s home, the BLM must adequately manage the activities there, including providing bathroom facilities,” said Donnelly. “Federal and state agencies have spent millions of dollars trying to save this special creature, and we commend them for the progress they’ve made. But it will all be for nothing, and the voles will vanish, if they don’t get use of the hot spring under control.”