The San Francisco Bay Area is one of the nation's six most important biodiversity hotspots. But as the area's human population continues to grow, urban sprawl is rapidly eliminating our remaining wildlands and habitat for imperiled species. Sprawl development projects — typically luxury homes and golf courses — are destroying and fragmenting important wildlife habitat, while simultaneously increasing traffic congestion and adding to air- and water-quality problems. More than 400,000 acres of natural landscape in the Bay Area are at risk of sprawl development.

The Bay Area's explosive growth, coupled with its rich biodiversity, has resulted in a high number of native species at risk. The area's nine counties are home to more than 90 animal and plant species listed as threatened or endangered under the federal Endangered Species Act. But despite the tremendous growth and development, no imperiled species with the good fortune to be listed has gone extinct in the bioregion — a testament to the Act's conservation power in the face of urban sprawl's intense pressure.

The Center has been working to protect biologically significant wildlands and habitat for imperiled species in the San Francisco Bay Area since 1997. The Center's efforts have provided Endangered Species Act protections for more than 35 Bay Area species, including the California red-legged frog, Alameda whipsnake, California tiger salamander, Central California Coast steelhead trout and coho salmon, southern green sturgeon, callippe silverspot butterfly, Bay checkerspot butterfly, Contra Costa goldfields, Suisun thistle, and yellow larkspur. The Center has forced the U.S. Fish and Wildlife Service to designate and protect hundreds of thousands of acres of critical habitat in the Bay Area for imperiled species. The Center also defends Endangered Species Act listings and critical habitat for species currently under attack from industry lawsuits and the Bush administration.


The Sacramento-San Joaquin Delta encompasses 1,600 square miles and drains more than 40 percent of California, with its waterways and wetlands forming the West Coast's largest estuary. The Delta provides habitat for numerous species of fish and wildlife, with nearly half of the state's migrating waterfowl and shorebirds and two-thirds of the state's spawning salmon passing through it. But at least a dozen of the Delta's original 29 indigenous fish species have been eliminated entirely or are currently threatened with extinction. Scientists are now warning of an ecological crash of fish populations and the Delta food web due to increasing water diversions for export, loss of habitat, increased competition and predation from introduced species, and impaired water quality caused by pesticides and other pollutants.

Since 2002, there has been a catastrophic collapse of the Delta's open-water fishes. The Center is working to secure Endangered Species Act protections for numerous native Delta fish species, including delta smelt, longfin smelt, green sturgeon, Sacramento splittail, Central Valley steelhead trout, and Pacific lamprey. Incredibly, in the face of crashing fish populations, the state and federal agencies charged with protecting the fisheries under the state and federal Endangered Species Acts have failed to protect the Delta's fish populations and have given approval for increased water diversions and more water storage projects. The Center and other conservation and fishing groups have a different vision of a restored Delta ecosystem and are fighting to reduce water exports, limit use of toxic pesticides, reverse declines of fish populations, and protect the ecology of one of the world's greatest estuaries.

San Francisco Bay photo by Rasmus Andersson/Flickr.