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.
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.
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.
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.