On 23 April 2004 the Xerces Society, the Center for Biological Diversity, the Nevada Outdoor Recreation Association, and Public Employees for Environmental Responsibility filed a petition with the U.S. Fish & Wildlife Service asking that the Sand Mountain Blue butterfly (Euphilotes pallescens arenamontana) be listed as endangered or threatened under the Endangered Species Act (source). On 5 January 2006 conservation groups filed a lawsuit in federal court to force the Service to consider the petition (source). According to an 8 August 2006 the Service published a notice in the Federal Register, the Service “reached an agreement with the
plaintiffs to submit to the Federal Register a completed 90-day finding
by July 28, 2006, and to complete, if applicable, a 12-month finding by
April 26, 2007.” The Federal Register notice points out that
The Sand Mountain blue butterfly is known only from Sand Mountain, Churchill County, Nevada, where it is dependent on its host plant, Kearney buckwheat...Kearney buckwheat is the sole food source for the larvae and an important nectar source for adults during their flight period.
The Service's species information page notes that “A study of aerial photos and satellite imagery has documented a significant loss of vegetative cover since 1979. During this time, visitor use increased from about 5,000 to over 35,000 visitors annually.” Nonetheless, a notice in yesterday's Federal Register concludes that “After a thorough review of all available scientific and commercial information, we find that the petitioned action is not warranted.” The Service based its conclusion on emergency restrictions placed on use of motorized vehicles in the area where the butterfly occurs and the large population that remains (several hundred thousand individuals in the 2006 flight season).
The implementation of this emergency restriction, and the high level of certainty of its effectiveness, has substantially reduced the magnitude and significance of any long-term threat posed by off-road vehicles to the habitat and viability of the Sand Mountain blue butterfly. Therefore, we conclude that the Sand Mountain blue butterfly is not now, or in the foreseeable future, threatened by destruction, modification, or curtailment of its habitat or range.
In particular, the Service argues that “the threats to the species are being addressed across its range...such that no area continues to face significant threats.”
I cannot claim firsthand knowledge of the butterfly, and I am not a lepidopterist, but the Service's finding strikes me as the result of a very narrow reading of the Endangered Species Act. The Act defines a species as endangered when it “is in danger of extinction throughout all or a significant portion of its range.” While it appears to be the case that the Sand Mountain Blue is in little danger of extinction if ORV use is prevented within its habitat, any species that occurs in only one population on a few only about 1,000 acres of land is very vulnerable, either to changes in land use policy or to extreme climatic events. The butterfly has only one brood per year, so a single severe drought could reduce a population of more than 100,000 to a few hundred in a single year. It seems to me that the Sand Mountain Blue is definitely in danger of extinction throughout all or part of its range and that the Fish & Wildlife Service made a mistake.
News reports about the decision:
Butterfly Won't Get Species Protection, The Washington Post
Sand Mountain Blue Butterfly won't be listed as endangered, Nevada Appeal
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