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The Range Contraction Project

Range Contractions of North American Carnivores and Ungulates

Many North American carnivores and ungulates have experienced dramatic changes in their geographic distribution since Euro-American settlement. The purpose of this study is to compare historic and current species ranges, identify large-scale patterns in species ranges and determine the degree of human influence on species range changes. Our results indicate that 17 of the 43 species analyzed experienced range contractions over more than 20% of their historic range. In areas of higher human influence, species were more likely to contract and less likely to persist. Species richness had declined considerably since historic times. The temperate grasslands and temperate broadleaf-mixed forest biomes lost the highest average number of species, while the boreal forest and tundra showed fewer numbers of species lost. These effects have been widespread and indicate a rapid collapse of species distributions over the course of only 1 to 2 centuries.

Scientific Articles

Range contraction maps

For a related study of human influences along the Lewis & Clark trail, please visit the Lewis & Clark project page.

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