Pacific Southwest Region
California, Nevada and Klamath Basin

Critical Habitat Proposed for Endangered Mount Charleston Blue Butterfly

Jul 14, 2014

July 14, 2014
Contact: Dan Balduini (702) 515-5480


Critical Habitat Proposed for Endangered Mount Charleston Blue Butterfly 

LAS VEGAS — The U.S. Fish and Wildlife Service (Service) today announced plans to designate approximately 5,561 acres on Mount Charleston in southern Nevada’s Spring Mountains as critical habitat for the endangered Mount Charleston blue butterfly. The land comprising the proposed critical habitat is 99 percent federally owned and mostly within designated wilderness. The butterfly was listed as endangered in October 2013 under the Endangered Species Act (ESA). The proposed critical habitat rule will appear in the Federal Register on Tuesday, July 15, 2014, opening a 60-day public comment period on the proposal. 

“Critical habitat” is a term in the ESA that identifies geographic areas of particular importance to the conservation of a threatened or endangered species. The ESA defines “conservation” as the actions leading towards the eventual recovery of a species to the point where it is no longer threatened or endangered. 

The Mount Charleston blue butterfly (Plebejus shasta charlestonensis) is a distinct subspecies of the wider-ranging Shasta blue butterfly. The butterfly occupies high elevations in the Spring Mountains National Recreation Area, approximately 25 miles west of Las Vegas. 

The Mount Charleston blue butterfly was given ESA protection due to the threat posed by the loss and degradation of its habitat. The species is likely to experience continued habitat loss due to changes in natural fire regimes and succession, fuels reduction projects, and the implementation of recreational development projects. Additionally, climate change and invasive nonnative plants will increase the inherent risk of extinction for the Mount Charleston blue butterfly. 

The acreage proposed as critical habitat for the butterfly contains host and nectar plants, as well as open areas essential to the conservation of the species. Plants upon which the Mount Charleston blue butterfly depends are Torrey’s milkvetch (Astragalus calycosus var. calycosus), Mountain oxytrope (Oxytropis oreophila var. oreophila), and Broad keeled milkvetch (Astragalus platytropis). 

The Service will hold a public information open house on the proposed critical habitat. The open house is scheduled for Tuesday, August 19, 2014, from 6 to 8 p.m. (PDT), at the Interagency Building located at 4701 N. Torrey Pines Drive, Las Vegas, Nevada, 89130. People needing reasonable accommodations in order to attend and participate in the open house are asked to contact Dan Balduini, Nevada Fish and Wildlife Office, as soon as possible via email to or by telephone at 702-515-5480. 

A copy of the proposed critical habitat rule can be viewed at Comments on this proposal will be accepted until at 11:59 p.m., on September 15, 2014, and may be submitted by one of the following methods: 

  • Electronically, via the Federal eRulemaking Portal, at In the Search box, enter FWS–R8–ES–2013–0105, which is the docket number for this proposed rule. Then, in the Search panel on the left side of the screen, under the Document Type heading, click on the Proposed Rules link to locate this document. Submit comments by clicking on “Comment Now!” 
  • Hard copy, via U.S. mail or hand delivery, to: Public Comments Processing, Attn: FWS–R8–ES–2013–0105; Division of Policy and Directives Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax Drive, MS 2042–PDM; Arlington, VA 22203. 

A copy of the final rule protecting the Mount Charleston blue butterfly as endangered and other information about the subspecies is available on the Internet at,, or through the Nevada Fish and Wildlife Office at 775-861-6300.


The ESA provides a critical safety net for America’s native fish, wildlife and plants. This landmark conservation law has prevented the extinction of hundreds of imperiled species across the nation and promoted the recovery of many others. Our priority is to make implementation of the ESA less complex, less contentious and more effective. We seek to accelerate recovery of threatened and endangered species across the nation, while making it easier for people to coexist with these species. 

The mission of the U.S. Fish and Wildlife Service is working with others to conserve, protect, and enhance fish, wildlife, plants, and their habitats for the continuing benefit of the American people. We are both a leader and trusted partner in fish and wildlife conservation, known for our scientific excellence, stewardship of lands and natural resources, dedicated professionals, and commitment to public service. For more information on our work and the people who make it happen, visit Connect with our Facebook page, follow our tweets, watch our YouTube Channel, and download photos from our Flickr page.