Conservation Groups Move To Protect Rare Washington Butterfly

For immediate release: September 28, 2004

Scott Hoffman Black, Executive Director, Xerces Society for Invertebrate Conservation; 503-534-2706
Noah Greenwald, Conservation Biologist, Center for Biological Diversity; (503) 243-6643

Less than 200 of the butterflies remain in the last population on San Juan Island

SEATTLE, WA– The Xerces Society for Invertebrate Conservation, Center for Biological Diversity, Northwest Environmental Defense Center, and Friends of the San Juans yesterday filed a lawsuit in federal district court in Seattle to compel the U.S. Fish and Wildlife Service to protect the Island Marble butterfly.

The Island Marble (Euchloe ausonides insulanus) is a beautiful white and green butterfly with a marbled texture under the hind wing. It historically inhabited open grasslands and Garry Oak woodlands on many of the San Juan Islands in Washington and on Gabriola and Vancouver Islands in Canada.  It had not been seen since 1908 and was believed extinct until one small population was found on San Juan Island in Washington State in 1998.

“Since the discovery of this population, scientists have surveyed surrounding sites on San Juan island and other nearby islands, but have not found any additional island marble populations,” said Scott Hoffman Black, Executive Director of the Xerces Society. “The entire known global population of this butterfly is less than 200 individuals and urgently needs conservation attention.”

In December of 2002, Xerces Society for Invertebrate Conservation, Center for Biological Diversity, and Friends of the San Juans filed a petition to protect the species as “endangered” under the Endangered Species Act. Despite the fact that the ESA mandates that the FWS determine if these species are indeed endangered within twelve months of the petition, it has been nearly two years and no action has been taken. The conservation groups are suing to force FWS to take action on the petition.

“The Island Marble is headed for extinction, yet the Bush Administration is dragging its feet protecting this rare butterfly,” states Noah Greenwald, conservation biologist with the Center for Biological Diversity.  “The Island Marble needs the safety net of the Endangered Species Act to survive.”

Habitat destruction is the primary cause of the island marble’s decline.  The butterfly was likely eliminated from most of its historic range because of the eradication of its larval hostplant by intensive livestock grazing, especially sheep, in the late 1800s and early 1900s. Development of Garry Oak woodlands and open prairies added to the destruction of the historic habitat of the island marble. Less than 5 percent of Garry Oak woodlands remain in Canada, and development pressure remains intense throughout the Pacific Northwest, especially on Vancouver Island and San Juan Island.

San Juan Island has the largest and fastest growing human population in the San Juan chain. Moreover, the American Camp, San Juan Island National Historic Park, which supports the last remaining population of island marble butterflies, is ringed with private housing developments and roads and paths are encroaching upon its open spaces.

With only one known population of fewer than 200 individuals, the butterfly is also threatened by natural factors, such as adverse weather. A large winter storm or drought could have severe consequences on a small population such as this one.

The conservation groups are represented by Robin Cooley of the Environmental Law Clinic at the University of Denver College of Law.

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