The Challenge of Mapping Amphibians and Reptiles

In 1997 the Department of Herpetology at the Academy began working with the U.S. Forest Service to assist in documenting the distribution of amphibians and reptiles of National Forests in California. Although distribution maps exist for most of the amphibians and reptiles occurring in California, they are of limited use, as their scale of resolution is at the statewide level and thus can be misleading when determining a species range of a specific area. Local species distributions, which may be closely linked to topography, local climate and edaphic factors (soil type), cannot be expected to be properly reflected in large scale maps.

Herpetological records for specimens collected in the Mendocino National Forest based on historic records and 1999-2001 surveys.

Realizing that an entire forest cannot be surveyed, predictive models are useful in determining the likely distribution of a species. However, such models require adequate information regarding habitat and elevation limits. For any model to be effective, baseline data are needed which directly pertain to a specific national forest.

We started the project by mapping all known specimen records from US museums which were collected from within the national forests. After the historical records are mapped, we determine areas that require surveying. Surveys are then conducted in the designated areas by members of the herpetology staff.

Combining the historical records with records from our surveys, we can now make geospatial correlations from our data. These data can then be used by the Forest Service to identify sensitive areas.

Foothill Yellow-legged Frog (Rana boylii)
Photo: Frank E. (Ed) Ely, California Academy of Sciences
Mendocino National Forest Mendocino County, CA. Photo: Gerald and Buff Corsi, California Academy of Sciences.