LAS VEGAS— The Center for Biological Diversity filed a notice today of its intent to sue the Trump administration’s U.S. Fish and Wildlife Service for failing to protect the endangered Mount Charleston blue butterfly from a proposed expansion of the Lee Canyon Ski Area, located in the Spring Mountains National Recreation Area of southern Nevada.

The expansion would open this ski area to increased summer recreation when the butterflies are active. It would include the construction and operation of a crisscrossing network of mountain-bike trails and a so-called “mountain coaster” in the heart of the species’ protected critical habitat.

The Mount Charleston blue butterfly, which was listed as endangered in 2013, has precariously low population numbers. Fewer than 100 individuals have been observed during surveys in the past five years.

“Lee Canyon’s plans to let mountain bikes bomb downhill through the sensitive habitat of this pretty little blue butterfly could be the nail in the coffin for this species,” said Patrick Donnelly, Nevada state director at the Center. “This is just another example of the Trump administration’s systematic dismantling of laws meant to protect our environment, and we’re not going to stand for it. We stand with the butterfly.”

Because the blue butterfly is protected under the Endangered Species Act, the Fish and Wildlife Service must ensure federal actions don’t jeopardize its existence or cause harm to its critical habitat. But in its formal evaluation of the project, the Service arbitrarily disregarded most of the butterfly’s critical habitat as “not suitable” for the butterfly, thus allowing for large-scale disturbance of its most sensitive habitats.

The Spring Mountains are one of North America’s great biodiversity hot spots, harboring dozens of plants and animals that live nowhere else on the planet. This butterfly relies on a suite of rare wildflowers for breeding and food, making it very sensitive to disturbances like those that could accompany downhill mountain-biking. The ski area currently harbors the most significant remaining population of the species, at least partially due to the lack of disturbance during the butterfly’s summer flight months.

“The Mount Charleston blue butterfly faces imminent danger of extinction if Lee Canyon’s plan to turn its protected critical habitat into an a downhill-sports amusement park comes to pass,” said Donnelly. “We’re taking action to stop the Trump administration’s reckless disregard for the Endangered Species Act, which is meant to save unique creatures like this butterfly.”