Mountain near Vegas gains blue butterfly habitat protection

LAS VEGAS — A scarce and endangered butterfly found only on Mount Charleston near Las Vegas is getting a kind of habitat insurance policy, under an agreement announced Monday by the federal government and a conservation group.

The U.S. Fish and Wildlife Service agreed to designate a little more than 8 square miles in alpine elevations as critical habitat for the Mount Charleston blue butterfly, said Daniel Balduini, an agency spokesman, and Tierra Curry, a Center for Biological Diversity scientist.

Curry called the butterfly one of the most endangered butterflies in the world, with fewer than 100 known to survive. Each is less than an inch long. Males are a dusky blue and gray, and females are a subdued brown-gray.

The 5,214 acres being set aside don’t include the Las Vegas Ski and Snowboard Resort and other developed areas including day use areas and campgrounds, Balduini said.

Protection, due to be logged Tuesday in the Federal Register, will take effect July 30.

It won’t halt all development in the area, which is within the Spring Mountain National Recreation Area managed by the U.S. Forest Service.

It will add extra scrutiny for projects, and discourage butterfly collecting.

Mount Charleston blue butterflies were classified as endangered in October 2013 amid worries that habitat was being harmed by fires, fire-suppression efforts and development.

The alpine habitat some 35 miles northwest of downtown contains host and nectar plants important to the insect, including Torrey’s milkvetch, mountain oxytrope and broad-keeled milkvetch.

It also includes open forest with little understory vegetation and exposed mineral soil — all vital to survival of the species, researchers say.

The Mount Charleston blue was first identified as a distinctive subspecies of the wider-ranging Shasta blue butterfly in 1928.