Events & Media



"The Downsizing of Nature:
Extinction Risk and Threats to the World’s Megafauna"

William J. Ripple
Distinguished Professor of Ecology
Oregon State University

Monday, February 13, 2017
11:30 - 12:30
Bren Hall 1414

"Dr. Ripple’s research on the ecological impacts of large predators in North America is sure to be of great interest to all. His collaborations and focus on science communication to conserve wildlife populations will provide great insights for those in the Bren community who are interested in conservation."

— Elizbeth Hiroyasu, PhD student host

I will present an illustrated talk on the conservation of megafauna by starting with large terrestrial mammals in North America during Pleistocene and historical times. I will then discuss the status and threats to the world’s largest terrestrial carnivores and herbivores. Next, I will move away from just mammals to examine all vertebrates and show the global extinction risk to the largest species of amphibians, mammals, reptiles, birds, bony fishes, and cartilaginous fishes. I will conclude by discussing how more than half of all vertebrate megafauna species are threatened with extinction and how some expected and surprising human activities are driving this global crisis. I will show parallels in how it is likely that the some of the same forces that obliterated late Pleistocene megafauna ten thousand to fifty thousand years ago appear to be continuing today.

Bill Ripple is Distinguished Professor of Ecology as well as Director of the “Global Trophic Cascades Program” at Oregon State University ( For the past twenty years, he has researched the ecological effects of wolves and other large predators in western North America. He and his graduate students were the first researchers to discover wolf-triggered trophic cascades in Yellowstone National Park. In recent years, he has expanded his research and collaborations to investigate the cascading ecological effects of vertebrates in other regions of the world. Much of his current work is focused globally on the conservation of wildlife populations, especially the megafauna. He has worked extensively communicating scientific results to the public via the mass media and documentary films.

NOTE: Bren seminars are hosted by Bren faculty members and are generally high-level talks about research in a particular area of environmental science and management.


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