BILLINGS, Mont.— Three conservation groups today announced their intent to sue the U.S. Fish and Wildlife Service for failing to protect the thick-leaf bladderpod, a rare plant found only at the base of the Pryor Mountains in southern Montana and northern Wyoming. The plant is under imminent threat from gypsum mining.

The lawsuit will be brought by the Center for Biological Diversity, Montana Native Plant Society and the Pryors Coalition.

Following a petition by the conservation groups seeking to list the thick-leaf bladderpod as endangered, the Service found that the species may warrant protection under the Endangered Species Act. But the agency then failed to decide whether to list the species as endangered within the required 12-month period.

“It’s crucial for the U.S. Fish and Wildlife Service to stop dragging its feet and start protecting these imperiled plants,” said Kristine Akland, Northern Rockies attorney at the Center. “There are so few of these little plants left, and until they get federal safeguards, they’ll be at the mercy of gypsum mining. This species isn’t found anywhere else on Earth, and we need to protect it.”

In 2015 the Bureau of Land Management designated an “area of critical environmental concern” to protect the thick-leaf bladderpod and recommended the area be closed to mining. Implementation of the recommendation stalled under the Trump administration. Gypsum mining is now a threat within the "area of critical environmental concern.”

“The chances of this plant persisting in the presence of an open-pit gypsum mine are small. Do we really want to sell out our state’s natural treasures to a foreign mining company?” said Peter Lesica, conservation chair of the Montana Native Plant Society.

Dick Walton, spokesperson for the Pryors Coalition, said, “The fragile soils and native vegetation in this arid landscape are unlikely to recover from damage by mining exploration within our lifetimes, if ever.”

The thick-leaf bladderpod is found on broad plains dominated by sparse vegetation. It grows in cryptobiotic soil crusts — living soils made of blue-green algae, lichens, mosses, micro fungi and bacteria. This small plant grows to a few inches in size and has tiny, yellow flowers that bloom only for a few weeks in June.

Gypsum exploration and mining would damage the bladderpod by removing vegetation and degrading the soil through drilling, excavation, road building and vehicle traffic. The exploration would also increase the threat of introducing invasive plants and incurring damage from off-road vehicles. The area’s cryptobiotic crust is highly sensitive to disturbances. Mining projects could lead to the extinction of the thick-leaf bladderpod unless the plant receives protection under the Endangered Species Act.