View Rule

We will designate critical habitat, if determined to be prudent and determinable, for the endangered Mount Charleston blue butterfly, pursuant to the Endangered Species Act. The Mount Charleston blue butterfly habitat occurs in the high elevations of the Spring Mountains, located approximately 25 miles (40 kilometers) west of Las Vegas in Clark County, Nevada. The natural habitat for the Mount Charleston blue butterfly is relatively flat ridgelines above 2,500 meters (m) (8,200 feet (ft)), but isolated individuals have been observed as low as 2,000 m (6,600 ft). Areas occupied by the subspecies feature exposed soil and rock substrates with limited or no canopy cover or shading.