Construction Is a Leading Threat to California Wildlife, Study Finds

Residential and commercial construction is the leading threat to the vast array of animals and plants at risk of extinction in California, according to a report released Tuesday by a national conservation group.

While logging, farming and water diversions often get the brunt of the blame, the National Wildlife Federation found that urban development poses a threat to more of California’s endangered species.

Urbanization--narrowly defined as construction of houses, offices and retail buildings--imperils 188 of the 286 species in California that are protected under the U.S. Endangered Species Act, according to the group’s analysis.

“When people think of endangered species, they think of bald eagles, wolves, grizzly bears. But the point is that endangered species are all around us,” said National Wildlife Federation President Mark Van Putten. “Unless we look at how we grow, we’ll have more of these problems.”

Conservationists intend to use the report’s findings as part of their growing national anti-sprawl movement, urging cities and counties to take a closer look at how land is developed.

Developers say that, as they build homes and businesses for Californians, they are already taking major steps to help endangered species. The Irvine Co., for example, in exchange for development rights, has set aside large tracts of valuable land in south Orange County.

David Smith, general counsel for the Building Industry Assn. of Southern California, said the report makes “sweeping judgments” that are “at least potentially misleading.”

He said California builders and developers “question the depth and accuracy of the data, and we question the productivity of a report like this in resolving two crucial issues--species conservation and the housing crisis.”

Wildlife experts say it’s impossible to isolate a single cause for the decline of biological diversity in California. In most cases, a variety of intertwined threats is responsible.

But in a comparison of 18 general factors, federal wildlife officials pinpoint urban development as one of the threats for 66% of the endangered species, more than any other factor. Nonnative species--from weeds to predators--came in second.

Paul Zedler, a biologist formerly at San Diego State University, called the study’s findings “very plausible.”

For wild animals and plants, few things can inflict as much damage as a bulldozer. The most severe and everlasting harm, Zedler said, comes from the simple physical loss of the natural landscape where they live.

“It’s the most fundamental problem and the most difficult to compensate for,” said Zedler, now an environmental studies professor at University of Wisconsin. “A lot of the species in California we’re worried about are coastal species, and that is where urban development is the greatest.”

Officials at the U.S. Fish and Wildlife Service, which enforces the Endangered Species Act, have long noted that destruction of natural habitat is the prime force behind California’s endangered species listings. And specifically, they say, the main cause is habitat fragmentation from urban sprawl.

“Urbanization, I would definitely say, is the major cause today,” agreed Pat Foulk, a spokeswoman for the California office of the wildlife agency.

Foulk said it is difficult to find any species in California whose decline is not directly linked to urban housing and commercial construction.

“The only recent listing that I can’t blame urbanization for directly is the Sacramento split-tail, a fish,” Foulk said.

Wildlife officials say sprawl into the San Joaquin Valley and Riverside, Orange and San Diego counties has left such a big footprint that it has created areas of high concentrations of endangered species. The development leaves “islands” of natural land where animals and plants are vulnerable to extinction.

Few people have ever heard of most of the 188 species imperiled by urban construction. The fairy shrimp. The milk vetch. The dudleya. More than half are plants. But as obscure as they are, the disappearance of such species indicates the elimination of a whole ecosystem, such as Southern California’s scrubby coastal hills or the Central Valley’s small seasonal pools.

Last year, a team of scientists reported that nationally, the leading factor in the imperiling of species is nonnative species, followed by urbanization. The conservation group, in studying California, used the same 18 categories developed by those scientists.

The group reported that urbanization is a double whammy, because it is closely associated with many of the other 17 threats, including road construction and water diversion.

The report, however, has some limitations, particularly because it simply counts species but does not quantify how big a role each factor plays in the decline of any individual species. For example, the bald eagle is included in the 188 species affected by urbanization, but the eagle’s decline was mostly caused by use of the pesticide DDT.

California’s steepest population growth--and consequently the biggest wildlife losses--occurred from the 1940s through the mid-1970s. But as animals and plants run out of room, today’s developers face many more restrictions on use of private property under the Endangered Species Act.

“It’s getting harder and harder to develop [in California] without having some impact on endangered species,” Zedler said.

A state agency recently reported that 200,000 new housing units per year must be built in California through the year 2020 to meet demographic projections.

“The building industry is working with conservation groups on smart growth concepts, but essential to smart growth is a smart housing policy,” Smith said.

Once a species is listed as endangered, projects that threaten its habitat must undergo a review by federal wildlife biologists. In recent years, the federal control over private land has been highly controversial in Congress. Conservation groups say new housing should be high-density and built in previously urbanized areas to avoid affecting wildlife. The Bush administration has not yet signaled how it will enforce the Endangered Species Act.