NatureServe Conservation Status
Rounded Global Status Rank: G2 - Imperiled
Reasons: Restricted to the central portion of California, where range and abundance have declined substantially as a result of habitat loss and degradation and other factors related primarily to human population growth and agricultural expansion. These factors, as well as hybridization with non-native tiger salamanders, effects of non-native species, and habitat fragmentation continue to threaten many populations. Although the species still occurs throughout most of the historical range and remains locally common in some areas, the recent and projected future rate of decline remains high. Consequently, the species was federally listed as Threatened rangewide in 2004.
Intrinsic Vulnerability: Moderately vulnerable
Comments: Populations can recover from drastic declines over a period of a few years, with high recruitment of juveniles. Given normal dispersal distances (see occurrence specifications), recolonization of habitats from which extirpated may be slow to absent if nearby populations within about 0.5-1 km are also extirpated.
USFWS (2002) reported the following: Lifetime reproductive success is low. Trenham (1998) found the average female bred 1.3 times and produced 8.5 young that survived to metamorphosis per reproductive effort; this resulted in roughly 11 metamorphic offspring over the lifetime of a female. One of the reasons for the low reproductive success is because individuals do not breed until they are 4 to 6 years old. While individuals may survive for more than 10 years, many may breed only once, and, in some populations, less than 5
percent of marked juveniles survive to become breeding adults (Trenham 1998). With such low
recruitment, isolated populations can decline greatly from unusual, randomly occurring natural events as well as from human-caused factors that reduce breeding success and individual survival. Factors that repeatedly lower breeding success in isolated ponds that are too far from other ponds for migrating individuals to replenish the population can quickly extirpate a population.
Environmental Specificity: Narrow. Specialist or community with key requirements common.
Comments: Species is a generalist with respect to terrestrial habitats, but reproduction is largely dependent on fishless bodies of water.