| The Sonoma California tiger salamander (SCTS) is a federally endangered vernal pool-breeding distinct population segment and the subject of conservation efforts consisting primarily of protecting existing populations in remnant habitat patches (preserves) in a rapidly urbanizing landscape. We conducted a 14-year (2002-2015) study of SCTS breeding activity at 112 pools on eight preserves encompassing all protected SCTS breeding sites at the time of federal listing in 2003. Our standardized dip-net surveys show a significant decrease in total SCTS larval abundance and number of pools used for breeding at preserves. Larval abundance was highly variable across years, with variability inversely correlated with preserve size and number of pools. The decline in larval abundance, likely indicative of a rapidly shrinking population, appears to result from habitat loss and fragmentation associated with urbanization, increasingly dry conditions over the study period, and predation (mostly by non-native vertebrate predators) in some deeper breeding pools. Our results suggest that a conservation strategy that only protects remnant habitats and populations is unlikely to successfully conserve SCTS, and additional active conservation management may be necessary to avoid extinction. |