CONSERVATION RELIANCE AMONG CALIFORNIA'S AT-RISK BIRDS

Conservation-reliant species require continuing management to ensure their long-term persistence. We qualitatively assessed the extent of conservation reliance for 92 California bird taxa listed under federal or California endangered species acts or recognized as California bird species of special concern. Habitat loss and fragmentation are the major threats for over 90% of these taxa, whereas interactions with predators or brood parasites threaten less than half, and human actions imperil roughly 40%. Some form of habitat enhancement is proposed to reduce the threats for most taxa, reinforcing the value of habitat-conservation strategies. Protecting habitat for wetland taxa and restoring habitat for island taxa appear to be particularly costly actions. Importantly, the species of special concern are every bit as conservation reliant as are taxa listed as endangered or threatened; management of these yet-unlisted taxa may be especially effective in preventing them from slipping into a more precarious status. Consideration of the magnitude of threats together with the degree of conservation reliance may help in prioritizing taxa for conservation. The philosophy and practice of conservation and resource management must recognize that continuing actions will be required to maintain the viability of populations of a great many species.