Amphibians are the least well-represented group in managed areas. As described in Chapter 3, CA-GAP predicted species distributions on the basis of range boundaries and the suitability of habitat types with the range. It does not guarantee that a species will occur at all locations that are modeled as suitable habitat. For some species, there are additional habitat elements that further control their distribution. Elements such as the presence of snags, proximity to surface water, or the adjacency of different critical habitat types, for example, are site-specific features that can not be detected at a regional scale with remotely sensed data.
Habitat structure is also a crucial factor in determining habitat suitability for many species.
Those species that are dependent on either these key habitat elements or on specific seral stages are likely to be grossly overestimated by our modeling methods. Species such as the California spotted owl and the fisher require mature stands of dense forest. This level of detail was also not compiled for CA-GAP, so suitability was based only on the type of habitat, not its structure. This overgeneralization of the distribution of some species has two possible effects. First, the overall distribution for such a species is likely to be overpredicted.