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For Immediate Release, August 26, 2008

Contact:  Shaye Wolf, (415) 436-9682 x 301
Jeff Miller, (510) 499-9185

Critical Habitat Designation Falls Short, Fails to Protect Unique, Threatened
Bay Checkerspot Butterfly From Urban Sprawl, Climate Change

SAN FRANCISCO— The U.S. Fish and Wildlife Service today slashed nearly a quarter of the designated critical habitat for the threatened Bay checkerspot butterfly and failed to protect key areas essential for its survival and recovery. This butterfly, which is found only in the San Francisco Bay area, is imperiled due to habitat loss and global warming. The final designation reduces by 23 percent the critical habitat designated for the butterfly in 2001 and fails to include sufficient habitat and dispersal corridors to buffer the Bay checkerspot from the escalating impacts of climate change.

“The Bay checkerspot butterfly is one of California’s early victims of global warming,” said Shaye Wolf, a biologist with the Center for Biological Diversity. “Rather than providing adequate, protected areas to help the Bay checkerspot survive in a warming world, the Fish and Wildlife Service is cutting holes in its safety net.”

The Bay checkerspot was once widespread throughout the native grasslands around San Francisco Bay. Urban development, overgrazing, and invasion of exotic grasses throughout the area have fragmented and degraded the butterfly’s habitat and severely reduced its populations. The butterflies now live only on a few small patches of habitat scattered around the serpentine soils in Santa Clara and San Mateo counties.

The survival of remaining Bay checkerspot populations is now being threatened by climate change, which is making extreme precipitation events such as droughts and flooding more frequent. That in turn reduces the availability of food plants for the butterfly’s larvae. Recent research has found that increases in extreme precipitation events over the past three decades have contributed to the extinctions of the butterfly’s populations at Jasper Ridge Biological Preserve in San Mateo County. To buffer the species from the extreme weather, a comprehensive network of protected habitat patches is needed, with varied topography and microclimates, each connected by steppingstone patches to allow for dispersal.

Today’s critical habitat designation falls short by reducing the area of protected habitat, instead of providing the necessary connected habitat network. In making this designation, the Fish and Wildlife Service ignored the conclusions of its own recovery plan for the butterfly. The plan cautions that nearly all known suitable habitats in San Mateo County, as well as central and western Santa Clara, western Alameda, and Contra Costa counties all will be needed to protect the Bay checkerspot. However, the new critical habitat includes areas in only two of those four counties — San Mateo and Santa Clara.

“Critical habitat should provide an essential lifeline for the Bay checkerspot butterfly,” Wolf said. “Species with designated critical habitat are twice as likely to improve as those without it. The Fish and Wildlife Service has neglected its responsibility to provide this unique Bay-area species with the habitat it needs to recover under changing climate conditions and continuing urban sprawl.”

Background on the Bay Checkerspot Butterfly

The Bay checkerspot is a medium-sized butterfly with a wingspan of about two inches. The forewings have black bands along all the veins on the upper wing surface, contrasting sharply with bright red, yellow, and white spots.

The checkerspot formerly occurred in five counties surrounding San Francisco Bay, from Twin Peaks and San Bruno Mountain (west of the Bay) to Contra Costa County (east of the Bay), south through Santa Clara County.

Adult Bay checkerspots are capable of dispersing over long distances. Movements of more than 4.7 miles have been documented.

The decline of the species is primarily attributed to habitat loss and fragmentation, now exacerbated by climate change, which is increasing the frequency of extreme precipitation events. Recent research has also identified excess nitrogen deposition from polluted air as a threat to the Bay checkerspot’s habitat, due to its fertilizing effect enhancing the growth of invasive nonnative plants.

The Bay checkerspot was listed as threatened under the Endangered Species Act in 1987. In 2001, the U.S. Fish and Wildlife Service finalized the designation of 23,903 acres of critical habitat for the Bay checkerspot butterfly in response to a lawsuit brought by the Center for Biological Diversity. The revised final critical habitat designation of 18,293 acres announced today follows a lawsuit by the Home Builders Association of California.

For more information on the Bay checkerspot butterfly, please see:

The Center for Biological Diversity is a national nonprofit conservation organization with more than 180,000 members and online activists dedicated to the protection of endangered species and wild places.

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