I am interested in the interactions of predator species and the causes and consequences of coexistence versus competitive exclusion. For example, my research explores the possiblity that wolves suppress coyotes, which allows fox populations to increase. This has implications for our understanding of how strongly top predators structure ecosysems. Our current research explores the role of bears in ecosystems, and how the widespread extirpation of brown bears has impacted ecosystems. We have particularly focused on the seed-dispersal services provided by brown bears and are increasingly interested in brown bears as predators.
We participate in a large collaborative project at Starkey Experimental Forest with GPS-collared bears, coyotes, bobcats, cougars, as well as cattle, deer, and elk. This intensive project allows for detailed understanding for how species interact.
Another major focus in recent years has been the ecology and conservation of small forest carnivores in the Pacific Northwest. Pacific fisher, Humboldt marten, and western spotted skunks have been our primary study systems.
Relevant Publications
Pedrosa, F., Bercê, W., Levi, T. Pires, M., Galetti, M. In revision. Invasive species promote critical seed dispersal services in defaunated landscapes
Pedrosa, F., Bercê, W., Costa, V.D., Levi, T., Galetti, M. In revision. Large scale agriculture is subsidizing the invasion of wild pigs in Brazil
Spitz, D.B., Rowland, M., Clark, D.A., Wisdom, M.J., Smith, J.B., Brown, C.L., Levi, T. In press. Non-consumptive behavioral responses and nutritional consequences of elk when avoiding human hunters. Ecosphere
Eriksson, C.E., Moriarty, K.M., Linnell, M.A., Levi, T. 2019. Biotic factors influencing the unexpected distribution of a Humboldt marten population in forested sand dunes. PLoS ONE
Spitz, D., Clark, D., Wisdom, M.J., Rowland, M., Johnson, B., Long, R.A. Levi, T. 2018. Fire history influences large-herbivore behavior at circadian, seasonal, and successional scales. Ecological Applications
Wolf, C., Betts, M. G., Levi. T., Newsome, T. M., Ripple, W. J. 2018. Large species within Carnivora are large carnivores. Royal Society Open Science
Shakeri, Y., White, K.W., Levi, T. 2018. Seed dispersal and resource subsidies from salmon-supported bears to granivores. Ecosphere
Linnell, M.A., Moriarty, K.M., Green, D.S., Levi, T. 2018. Density and population trajectories of coastal marten: a rare and geographically isolated small carnivore. PeerJ
Ostfeld, R.S.*, Levi, T.*, Keesing, F., Oggenfuss, K. Canham, C.D. 2018. Tick-borne disease risk in a forest food web. Ecology*authors contributed equally
Smith, J.A., Thomas, A.C. , Levi, T., Wang, Y., Wilmers, C.C. 2018. DNA metabarcoding reveals human-induced shifts in dietary niche partitioning in a carnivore guild. Oikos
Harrer, L.E.F., Levi, T. 2018. The primacy of bears as seed dispersers in salmon-bearing ecosystems. Ecosphere
White, K.S., Gregovic, D., Levi, T. 2017. Projecting the future of an alpine ungulate under climate change scenarios. Global Change Biology
Adams, M.S., Service, C., Bateman, A., Bourbonnais, M., Artelle, K., Nelson, T., Paquet, P., Levi, T., Darimont, C.T. 2017. Intrapopulation isotopic niche diversity over landscapes; spatial patterns inform conservation of bear-salmon systems. Ecosphere
Ripple, W.J., Chapron, G., Lopez-Bao, J.V., Durant, S.M., Macdonald, D.W., Lindsey, P.A., Bennett, E.L., Beschta, R.L., Bruskotter, J.T., Campos-Arceiz, A., Corlett, R.T., Darimont, C.T., Dickman, A.J., Dirzo, R., Dublin, H.T., Estes, J.A., Everatt, K.T., Galetti, M., Goswami,V.R., Hayward, M.W., Hedges, S., Hoffman, M., Hunter, L.T.B., Kerley, G.I.H., Letnic, M., Levi, T., Maisels, F., Morrison, J.C., Nelson, M.P., Newsome, T.M., Painter, L., Pringle, R.M., Sandom, C.J., Terborgh, J., Treves, A., Valkenburgh, B.V., Vucetich, J.A., Wirsing, A.J., Wallach, A.D., Wolf, C., Woodroffe, R., Young, H., Zhang, Li. 2016. Conserving the World’s Megafauna and Biodiversity: The Fierce Urgency of Now. Bioscience.
Wheat, R.E., Allen, J.M., Miller, S.D.L, Wilmers, C.C., Levi, T. 2016. Environmental DNA from residual saliva for efficient noninvasive genetic monitoring of brown bears (Ursus arctos). PLoS ONE
Ripple W.J., Abernethy, K., Chapron, G., Levi, T., Lindsey, P.A., Newsome, T.M., Peres, C.A., Wallach, A.D., Wolf, C. 2016. Are we eating the world’s mammals to extinction. Royal Society Open Science
Antunes, A.P., Fewster, R., Venticinque, E.M., Peres, C.A., Levi, T., Rohe, F., Shepard-Jr, G.H. 2016. Empty rivers rather than empty forests: a century of commercial hunting in Amazonia. Science Advances
Ripple, W.J., Chapron, G., Lopez-Bao, J.V., Durant, S.M., Macdonald, D.W., Lindsey, P.A., Bennett, E.L., Beschta, R.L., Bruskotter, J.T., Campos-Arceiz, A., Corlett, R.T., Darimont, C.T., Dickman, A.J., Dirzo, R., Dublin, H.T., Estes, J.A., Everatt, K.T., Galetti, M., Goswami,V.R., Hayward, M.W., Hedges, S., Hoffman, M., Hunter, L.T.B., Kerley, G.I.H., Letnic, M., Levi, T., Maisels, F., Morrison, J.C., Nelson, M.P., Newsome, T.M., Painter, L., Pringle, R.M., Sandom, C.J., Terborgh, J., Treves, A., Valkenburgh, B.V., Vucetich, J.A., Wirsing, A.J., Wallach, A.D., Wolf, C., Woodroffe, R., Young, H., Zhang, Li. 2016. Saving the world’s terrestrial megafauna. Bioscience. P.biw092
Fragoso, J.M.V., Levi, T., Oliveira, L.F.B., Luzar, J.B., Overman, H., Read, J.M., Silvius, K.M. 2016. Line transect surveys under detect terrestrial mammals: implications for the sustainability of subsistence hunting. PLoS ONE
Peres, C.A., Emilio, T., Schietti, T., Desmoulière, S.J.M, Levi, T. 2016. Dispersal limitation induces long-term biomass collapse in overhunted Amazonian forests. Proceedings of the National Academy of Sciences. 113: 892-897
Beschta, R.L., Painter, L.E., Levi, T., Ripple, W.J. 2016. Long-term aspen dynamics and trophic cascades in Northern Yellowstone. Canadian Journal of Forest Research. 46: 548-556
Ripple, W.J., Newsome, T.M., Wolf, C., Dirzo, R., Everatt, K.T., Galetti, M., Hayward, M.W., Kerley, G.I.H., Levi, T., Lindsey, P.A., Macdonald, D.W., Malhi, Y., Painter, L.E., Sandom, C.J., Terborgh, J., Van Valkenburgh, B. 2015. Collapse of the World’s Largest Herbivores. Science Advances. 1(4): e1400103
evi, T., Silvius, K.M., Oliveira, L.F.B, Fragoso, J.MV. 2013. Competition and facilitation in the capuchin-squirrel monkey relationship. Biotropica. doi:10.1111/btp.12046
Levi, T., Peres, C.A. 2013.Dispersal vacuum in the seedling recruitment of a primate-dispersed Amazonian tree. Biological Conservation. 163:99-106
Wilmers, C.C., Levi, T. 2013. Do irrigation and predator control reduce the productivity of migratory ungulate herds?Ecology. 94:1264–1270
Wilmers, C.C., Ram, K., Watson, F.G.R, White, P.J., Smith, D.W., Levi, T. 2013. Climate and vegetation phenology – Predicting the effects of warming temperatures. inWhite, P.J., editor. Yellowstone’s Wildlife in Transition. Harvard University Press
Levi, T., Kilpatrick, A.M., Mangel, M., Wilmers, C.C. 2012. Deer, predators, and the emergence of Lyme disease. Proceedings of the National Academy of Sciences.109:10942-10947
Levi, T., Darimont, C.T., MacDuffee, M., Mangel, M., Paquet, P., Wilmers, C.C. 2012. Using Grizzly bears to assess harvest-ecosystem tradeoffs in salmon fisheries. PLoS Biology. 10(4)
Levi, T., Wilmers, C.C. 2012. Wolves-Coyotes-Foxes: A cascade among carnivores.Ecology. 93:921-929