Because of the difficulties involved in estimating population numbers for an amphibian species like the California tiger salamander (Ambystoma californiense), there is currently no estimate of population numbers for the species as a whole, nor is there a historical population estimate.

But many studies have shown that although total population numbers aren't known, the population is declining.

The California tiger salamander was first described as a distinct species in 1853 from specimens collected in Monterey. Scientists have checked for salamanders at all the historic sites of California tiger salamander habitat, and they have found that the population has declined 30-50%.

Intensive human habitat development over the past 150 years has resulted in the loss of approximately 75% of the historic vernal pool (rain pond) breeding habitat of the salamanders. This loss of suitable habitat, and the effect of non-native competing species and chemical pollution, are probably the main causes of the salamander decline. The California tiger salamander is listed as a "species of special concern" by the State government, and as Endangered at the Federal level (but listed as endangered only in Santa Barbara County).