The Island Marble (Euchloe ausonides insulanus) is a white and greenish butterfly with a marbled texture under the hind wing and a wingspan of approximately 45 mm. Historically it occurred in grasslands and Garry oak woodlands on southern Vancouver Island, the Gulf Islands, and the San Juan Islands. It is now extirpated from Vancouver Island and the Gulf Islands.

Photo by Bill Yake
Thought extinct since the 1920's, the island marble was rediscovered on San Juan Island in 1998. A small chance exists that additional populations may exist on other islands in the San Juan archipelago though surveys have not located any.

The primary cause of the island marble's decline is the loss of its habitat: grasslands, prairies, and Garry oak woodlands. Ninety-five percent of the Garry oak woodlands on Vancouver Island have been lost to cattle grazing, agriculture, urban and suburban sprawl, fire suppression, and invasion of exotic species. Pesticide spraying is also a threat.

On December 10, 2002 the Center For Biological Diversity, Xerces Society, Friends of the San Juans, and Northwest Ecosystem Alliance filed a petition with the U.S. Fish and Wildlife Service to protect the island marble under the Endangered Species Act. Listing under the ESA will require protection of specific grasslands, prairies, and woodlands as "critical habitat" for the butterfly and the development of federal recovery plan. It will ensure that federal agencies act to save the island marble while encouraging state and private interests to participate as well.

graphic Andrew Rodman ©2002
July 31, 2003
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