Home Page | Global Trophic Cascades Program

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Global Trophic Cascades Program is a research and educational program with the purpose of investigating the role of predators in structuring ecological communities. This program puts special emphasis on the role of potential keystone species in top-down community regulation, with linkages to biodiversity via trophic cascades.

A graduate degree concentration is available as part of the Trophic Cascades Program. Designed for students interested in topics that intersect forestry and wildlife science, this concentration provides an interdisciplinary approach to attaining sustainability of both forest and wildlife resources. Available within the Department of Forest Ecosystems and Society, the forestry/wildlife degree concentration involves dynamic interaction with faculty in both the College of Forestry and the Department of Fisheries & Wildlife. For more information, go to Graduate Studies.


Participating Faculty/Scientists

  • William J. Ripple, Professor, Dept. of Forest Ecosystems and Society; Director, Trophic Cascades Program.
    (More info...)
  • Robert L. Beschta, Professor Emeritus, Dept. of Forest Ecosystems and Society.
    (More info...)
  • Matthew G. Betts, Assistant Professor, Dept. of Forest Ecosystems and Society.
    (More info...)
  • Julia C. Buck, Postdoctoral Research Fellow, University of California Santa Barbara.
    (More info...)
  • James A. Estes, Professor, University of California, Santa Cruz.
    (More info...)
  • Matt Hayward, School of Environment, Natural Resources and Geography, Bangor.
    (More info...)
  • Jan Kamler, Research Associate, Wildlife Conservation Research Unit, University of Oxford.
    (More info...)
  • Graham Kerley, Centre for African Conservation Ecology
    (More info...)
  • Mike Letnic, Associate Professor, School of Biological, Earth and Environmental Sciences.
    (More info...)
  • David Macdonald, WildCRU, Professor, Zoology, University of Oxford.
    (More info...)
  • Taal Levi, Assitant Professor, Department of Fisheries and Wildlife, Oregon State University.
    (More info...)
  • Michael P. Nelson, Professor, Department of Forest Ecosystems and Society.
    (More info...)
  • Thomas Newsome, Postdoctoral Scholar.
    (More info...)
  • Luke Painter, Instructor, Department of Fisheries and Wildlife, Oregon State University.
    (More info...)
  • Jonah Piovia-Scott, Assistant Professor, School of Biological Sciences, Washington State University, Vancouver.
    (More info...)
  • Arian Wallach, Charles Darwin University, School of Environment.
    (More info...)
  • Aaron Wirsing, Associate Professor, School of Environmental and Forest Sciences, University of Washington.
    (More info...)
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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