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Carson Valley Silverspot
(Speyeria nokomis carsonensis)

Carson Valley Silverspot
Carson Valley Silverspot
© Wendy Broadhead

Appearance
The Carson Valley silverspot is a large orange and black butterfly that in form and color somewhat resembles the striking and well-known monarch butterfly. The silverspot gets its name from the beautiful array of silver spots on the undersides of its hindwings, which are orange in the males and blue in the females.

Habitat
The Carson Valley silverspot once occurred along the Carson River drainage in Douglas County, Nevada, and Alpine County, California in areas where its larval hostplant (Viola nephrophylla) and a nectar source (primarily thistles) grew. Populations also have been found in the Sweetwater Mountains and along the Walker River drainage in Mono County, California.

Threats
Land use changes such as suburban sprawl have reduced the silverspot's range considerably. Now just a few individuals are found in very small remnant colonies along the upper Carson River in California, and the only known colony left in Nevada is in a small, boggy meadow at the Scossa Ranch in Douglas County. While this colony is thriving at present, any habitat disturbance, including small changes in the water table, could adversely affect the availability of the butterfly's larval hostplant and then the butterfly itself. Because of the importance of the larval hostplant and adult nectar sources on silverspot populations, overgrazing is also a potential threat.

What the Conservancy is Doing
Biologists from the University of Nevada, Reno have surveyed for the Carson Valley silverspot at the River Fork Ranch in the Carson Valley. Although they didn't find a population of the butterfly there, they identified sites where wet meadow habitats with populations of its larval hostplant potentially could be restored so that this magnificent butterfly can once more be secure in the only place in the world it exists.