Scale Dependence of Species Richness Maps∗

∗Support for this research was provided through grants from NASA (NAGW-1743), the National Fish and Wildlife Foundation, and the Southern California Edison Company. The habitat and species data were compiled for the Idaho Gap Analysis Project by the Idaho Cooperative Fish and Wildlife Research Unit under the leadership of Mike Scott. I thank Blair Csuti, Frank Davis, Jack Estes, Mike Goodchild, Mike Scott, and two anonymous reviewers for many useful comments on drafts of the manuscript.

Mapping patterns of species richness is a longstanding tradition in biogeography and more recently in conservation planning. This paper describes the effects of sampling unit size on patterns of vertebrate richness across landscapes in the Intermountain Sagebrush and Rocky Mountain Forest ecoregions in Idaho. Variability of richness decreased with increasing size of the spatial sampling units at both sites, with greater overall variability in the forested site. Richness in the sagebrush region was best explained by alpha diversity, whereas beta diversity accounted for more of the variability in richness in the forested site.

Key Words:

• scale
• gap analysis
• Idaho
• GIS
• biodiversity

Notes

∗Support for this research was provided through grants from NASA (NAGW-1743), the National Fish and Wildlife Foundation, and the Southern California Edison Company. The habitat and species data were compiled for the Idaho Gap Analysis Project by the Idaho Cooperative Fish and Wildlife Research Unit under the leadership of Mike Scott. I thank Blair Csuti, Frank Davis, Jack Estes, Mike Goodchild, Mike Scott, and two anonymous reviewers for many useful comments on drafts of the manuscript.