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William J. Ripple

William J. Ripple is a professor of ecology at Oregon State University in the Department of Forest Ecosystems and Society. He is best known for his research on terrestrial trophic cascades, particularly the role of the gray wolf (Canis lupus) in North America as an apex predator and a keystone species that shapes food webs and landscape structures via “top-down” pressures.

William J. Ripple
William Ripple Iron Moutain.jpg
William Ripple in 2010.
Born (1952-03-10) 10 March 1952 (age 67)
ResidenceUnited States
Alma materSouth Dakota State University,
University of Idaho College of Mines and Earth Resources,
Oregon State University
Known forResearch of landscape-level trophic interactions involving apex predators and large herbivores
Scientific career
InstitutionsOregon State University
WebsiteTrophic Cascades Program

Ripple heads the Trophic Cascades Program at Oregon State University, which carries out several research initiatives such as the Aspen Project, the Wolves in Nature Project, and the Range Contractions Project.[1][2] He has a Ph.D. from Oregon State University[1]

Ripple was the lead author on the "Global Scientists' Warning to Humanity: A second Notice", published on November 13, 2017.[3] This article includes 15,364 scientist co-signatories from 184 countries. The article suggests "To prevent widespread misery and catastrophic biodiversity loss, humanity must practice a more environmentally sustainable alternative to business as usual."


William Ripple is the author of more than 100 peer-reviewed scientific articles, most of which deal with trophic cascades.[4]

Ripple, along with his frequent coauthor, Robert Beschta, have studied, published, and publicized the positive impact that gray wolves have had on the Yellowstone National Park ecosystem since their reintroduction in 1995 and 1996.[5]  These studies were featured in National Geographic Magazine,[6] Discover Magazine,[7] Smithsonian Magazine,[8] and Scientific American.[9]  Their research was also featured in the William Stolzenburg book, Where the Wild Things Were: Life, Death, and Ecological Wreckage in a Land of Vanishing Predators,[10] and the documentary film Lords of Nature: Living in a Land of Great Predators.[11]

Ripple's research carries a large focus on the gray wolf, particularly in the Greater Yellowstone Ecosystem, but has also studied the impact of other large North American predators, such as the cougar (Puma concolor).[12] He has coauthored papers with other scientists in the field of trophic cascades and apex predators,[13] including an exhaustive review of the status and ecological impacts of the world's 31 largest mammalian carnivores.[14] He led an international team of scientists reviewing the status and ecological effects of the world's largest herbivores.[15] Ripple has also applied trophic cascade theory to the subject of the Pleistocene megafaunal extinctions. The hypothesis being that North American Pleistocene megafauna existed at low population densities, primarily limited by the apex predators of the time. The arrival of a novel and essentially invasive top predator (humans) could have driven these predator-limited populations to extinction.[16]

More recently, William Ripple has participated in publications addressing issues that are not immediately related to the subject of trophic cascades. One such article, published in the journal Nature Climate Change, advocates for reducing the total ruminant population in global agriculture as a means to combat anthropogenic climate change. Because methane is an important greenhouse gas, reducing a leading source of human-driven methane emissions such as those from ruminants could have a significant role to play in efforts to mitigate climate change.[17]

Awards and honorsEdit

  • 2014 - Oregon State University; “2014 Distinguished Professor Award”.[18]
  • 2011 - Oregon State University; “L.L. Stewart Faculty Scholars Program award”.[19]
  • 2009 - Defenders of Wildlife; “Spirit of Defenders Award for Science”, for his work studying the links between top predators and healthy ecosystems.[20]
  • 2008 - High Desert Museum; “Earle A. Chiles Award” for his research on trophic cascades and “pioneering new ways of interpreting predator, prey and plant relationships in High Desert ecosystems, and improving ecosystem management.”[21]
  • 1996 - American Society for Photogrammetry and Remote Sensing (ASPRS) Fellow.[22]


  • William J. Ripple and Nicholas R. Houtman (2019). "Chapter 2: Scientists' warnings have been ignored". In Extinction Rebellion (ed.). This Is Not a Drill: An Extinction Rebellion Handbook. Penguin Books. pp. 28–30. ISBN 9780141991443.


  1. ^ a b "Ripple, William J." Oregon State University Department of Forest Ecosystems and Society. Faculty. Oregon State University. Retrieved 9 March 2012.
  2. ^ "Oregon State University Department of Forest Ecosystems and Society". Trophic Cascades Program. Retrieved 9 March 2012.
  3. ^ Ripple WJ, Wolf C, Newsome TM, Galetti M, Alamgir M, Crist E, Mahmoud MI, Laurance WF (13 November 2017). "World Scientists' Warning to Humanity: A Second Notice". BioScience. 67 (12): 1026–1028. doi:10.1093/biosci/bix125.
  4. ^ Oregon State University Department of Forest Ecosystems and Society. Trophic Cascades Program. Scientific Articles. Retrieved 14 April 2014.
  5. ^ Ripple, W.J., Beschta, R.L., 2012. Trophic cascades in Yellowstone: The first 15 years after wolf reintroduction. Biological Conservation 145, 205–213.
  6. ^ Chadwick, D. March, 2010. Wolf Wars. National Geographic Magazine.
  7. ^ Smith, J. F., Coffey, R., Fang, J. May, 2010. DESTINATION SCIENCE: YELLOWSTONE NATIONAL PARK, USA. Discover Magazine.
  8. ^ Jaffe, E. December, 2006. It All Falls Down: A plummeting cougar population alters the ecosystem at Zion National Park. Smithsonian Magazine.
  9. ^ Robbins, J. May, 2004. Lessons from the Wolf. Scientific American.
  10. ^ Stolzenburg, William. 2008. Where the Wild Things Were: Life, Death, and Ecological Wreckage in a Land of Vanishing Predators. Bloomsbury USA, New York.
  11. ^ Lords of Nature: Life in a Land of Great Predators. 2009.
  12. ^ Ripple, W. J., Beschta, R.L., 2006. Linking a cougar decline, trophic cascade, and catastrophic regime shift in Zion National Park. Biological Conservation. 133, 397–408.
  13. ^ Estes, J. A., et al., 2011. Trophic Downgrading of Planet Earth. Science. 333, 301-306.
  14. ^ Ripple, W.J., et al. 2014. Status and Ecological Effects of the World's Largest Carnivores. Science. 343.
  15. ^ Ripple, William J., et al. 2015. Collapse of the world's largest herbivores. Science Advances. 1.4, e1400103.
  16. ^ Ripple, W. J. & Valkenburgh, B. V., 2010. Linking Top-down Forces to the Pleistocene Megafaunal Extinctions. BioScience. Vol. 60 No. 7. 516 - 526.
  17. ^ Ripple, W.J., et al. 2014. Commentary: Ruminants, climate change and climate policy. Nature Climate Change. 4.
  18. ^ Oregon State University Academic Affairs. OSU selects public health leader, ecologist for Distinguished Professor Awards. Accessed 16-March-2014.
  19. ^ Oregon State University Academic Affairs. The L.L. Stewart Faculty Scholars Project Summary - Bill Ripple. Accessed 09-March-2012.
  20. ^ 14. Oregon State University, University Relations and Marketing, News & Research Communications. September, 2009. Ripple receives national honor from Defenders of Wildlife. Accessed 09-March-2012.
  21. ^ High Desert Museum. High Desert Museum Honors Ecologist Dr. William Ripple with Earle A. Chiles Award. Accessed 09-March-2012.
  22. ^ American Society for Photogrammetry and Remote Sensing. Fellow Award Recipients. Accessed 09-March-2012.