EPA/600/A-98/134.Corvallis scientists report on a multi-organization study that looked at biodiversity as a two stage problem. The first stage is finding those places over a region of study that have the greatest combined biodiversity, and the second stage is studying those important places to see what effects changes in land use caused by human activities might have on biodiversity. For the purposes of the study in land use caused by human activities might have on biodiversity. For the purposes of the study biodiversity was defined as species richness and habitat abundance of amphibians, reptiles, birds, and mammals, and for the total of these four taxonomic groups.