Nevada Butterflies May Warrant Protection

Feds to Study Rare Spring Mountains Butterflies for Endangered Species Act Listing

Las Vegas – The U.S. Fish and Wildlife Service has announced that it will consider the Spring Mountains dark blue butterfly for listing as “threatened” or “endangered” under the Endangered Species Act (ESA). The dark blue was considered a single species until 2008, when experts determined the population was comprised of two biologically distinct subspecies. WildEarth Guardians petitioned to list both subspecies under the ESA in September 2011.

“We are pleased that the Service will consider these butterflies for listing,” said Mark Salvo, Wildlife Program Director for WildEarth Guardians. “These rare, unique subspecies deserve federal protection.”

The two subspecies of Spring Mountains dark blue butterfly (Euphilotes ancilla cryptica and Euphilotes ancilla purpura) are endemic to the Spring Mountains, a “sky island” and hot spot for biological diversity in southern Nevada. The two species look alike, but emerge at different times of the year and use different host plants. E. a. cryptica is more widespread, though less numerous than purpura. Both subspecies occur as small, scattered populations in piñon pine-juniper and mixed ponderosa pine/white fir forest.

The Spring Mountains dark blue butterfly mostly occurs on public land in the Spring Mountains National Recreation Area administered by the Humboldt-Toiyabe National Forest. Vegetation treatments, fire management, grazing, drought and climate change have exposed, dried out and killed the butterflies’ host plants. Experts are also concerned that populations of both butterfly subspecies may be declining.

The Fish and Wildlife Service, having determined that WildEarth Guardians’ petition presented substantial information indicating that listing the subspeicies may be warranted, will now determine whether to propose the species for listing under the ESA.