Political conflict is common wherever urban development pushes into habitat occupied by imperiled wildlife. Every state and region has its own battlegrounds, but nowhere in the United States is the collision between human population pressures and natural ecosystems more pronounced than on California's rapidly growing south coast. The conflict is particularly acute in San Diego County, a biological hotspot with a booming human population. To address this, the county has become a nationwide example of large-scale conservation planning's promise — such as dedication of large tracts of land for rare plants and animals — and its pitfalls — including a planning process that lasts longer than most presidential administrations. The latest example will enter its final phase in March. San Diego County's 4,200 square miles are home to 24 plant and animal species that are listed or proposed for listing as endangered by the federal or state governments, 300 species that are considered "sensitive," and more "species of concern" than any other county in the continental United States. The county also is undergoing explosive population growth, particularly in the northwest coastal area. From 1990 to 1999, population in that region grew by 19%, and the number of housing units increased 11%. That growth rate exceeded both that of the rest of San Diego County (12.6% during the decade) and the state (13.6%). Demographers say the total population of the cities on and near the county's northwest coast will grow from about 630,000 today to more than 800,000 by 2020. Negotiating or litigating protection for wildlife one species at a time, or one project at a time, can inflict economically painful uncertainty and delay on property owners and builders, while also slowing protection and recovery of imperiled plants and animals. To avoid these problems, San Diego County embraced the concept of large-scale conservation planning involving many pieces of property, species and agencies. The Habitat Conservation Plan (HCP) process, authorized under the U.S. Endangered Species Act (ESA), and the Natural Community Conservation Program (NCCP), operating under the California Endangered Species Act (CESA), encourage San Diego County's approach. These HCPs and NCCPs consist of contracts between local agencies or landowners and the state and federal governments. The applicants commit to certain conservation actions — setting aside acreage as habitat preserve, for example — and in return are issued "incidental take" permits under the ESA and CESA. Those permits allow the destruction of a protected species or its habitat outside the preserve, as long as the damage occurs during the course of otherwise lawful activities. When negotiated by public agencies such as cities or counties, HCP/NCCP restrictions are subsequently written into local land-use plans, allowing the permitting agencies to obtain incidental take permits from the state and federal governments. Those exemptions from ESA and CESA prohibitions are then extended to private developers who obtain permits from the local agencies. Although more than 400 HCPs have been negotiated nationwide, the three under way in San Diego County are among the most complicated and far-reaching. The largest and oldest is known as the Multiple Species Conservation Program (MSCP), begun during the 1980s. The MSCP focuses on the city of San Diego and its surroundings in the south county, including the cities of Santee and Chula Vista. Its goal is to set aside 170,000 acres in a network of habitat preserves, protecting 85 plant and animal species. Although the overall MSCP has been approved by all the participating agencies, it remains incomplete despite nearly two decades of work; Santee and Chula Vista are still preparing their own specific conservation plans to implement the MSCP, as well as required environmental documents. The second agreement is known as the North County Multiple Habitat Conservation Program (MHCP), and work on it began during 1991. It will set aside 19,000 acres of habitat preserve for 60 species around the fast-growing cities of Carlsbad, Encinitas, Escondido, Oceanside, San Marcos, Solana Beach and Vista. The MHCP is scheduled for San Diego Association of Governments board action on March 28. The third conservation plan will encompass more than 1 million acres of unincorporated land mainly in the east county. That effort, according to Janet Fairbanks, SANDAG senior regional planner, is years from completion. Given the bureaucratic complexity of the multi-jurisdictional landscape, it is not surprising that San Diego County communities have been working on the HCP/NCCP process for two decades. "It has been daunting, difficult, challenging, but not impossible," Fairbanks said. "Herding cats is the best description." But the long delay — during which population continues to grow, development pressures accelerate and the number of imperiled species increases — is not the only weakness of such large-scale HCPs. The process itself has been criticized for the shaky science underpinning many conservation plans. This is one of the concerns that led the Center for Biological Diversity to sue the U.S. Fish and Wildlife Service over its decision not to put species on the endangered list on the grounds that the MSCP already provided adequate protection. When such plans emerge from the political process — as has been the case with the MHCP and MSCP in San Diego County, developed by large advisory committees composed of numerous stakeholders — biology can be shoved even further into the background. Nearly half the acreage identified as habitat preserve in the draft MHCP, for example, is already public forest or parkland at no risk of development. As for the rest, the plan specifies that private land will be added to the preserve only by requiring dedication as mitigation for specific projects, or by public purchase from willing sellers. So far, Fairbanks said, acquisition has not been a problem. "Acquisitions have occurred at a faster pace than any of us anticipated," she said. "The City and County of San Diego have both reached into their general funds to purchase land, something we were not expecting. Plus, the state of California passed Proposition 40 last year and Proposition 50 this year with specific funds allocated for habitat acquisition." Nevertheless, with municipal budgets straining thanks to California's fiscal crisis, there is no guarantee that local money will continue to be available, nor is there a guarantee that willing sellers will always be found. And without the private-land component, the habitat preserves identified in the HCP/NCCP agreements will never be able to provide the full ecological benefits they promise. Contacts: Janet Fairbanks, SANDAG, (619) 595-5370. Center for Biological Diversity, (619) 574-6800. San Diego MSCP plan summary, www.sannet.gov/mscp/plansum/shtml North County MHCP draft, www.sandag.org/index.asp?projectid=97&fuseaction=projects.detail