Fryxell, John - University of Guelph - Department of Integrative Biology

个人简介

B.Sc. - Britsh Columbia 1977 Ph.D. - British Columbia 1985

研究领域

My research focuses on interactions between behavior and consumer-resource dynamics. A mix of theoretical and empirical approaches is used to consider the dynamics of specific systems. Theoretical questions of interest include herbivore and carnivore movement in relation to resource availability and predation risk, optimal diet, patch selection, and dispersal patterns in heterogeneous environments, the effect of social interference and territoriality on consumer-resource interactions, and impacts of harvesting by humans on fish and mammal populations. Empirical work has been concentrated on 3 different terrestrial ecosystems over the past decade: large herbivores and carnivores in Serengeti National Park (Tanzania), woodland caribou, wolves, and moose in boreal forests of northern Ontario (Canada), and mustelid carnivores and other small mammals in boreal forests of northern Ontario. In each case, my graduate students and I conduct detailed field and experimental studies of behavioral ecology of both predators and prey. Theoretical models are then used to assess the implications of behavioral strategies on population and community dynamics and model predictions are then tested against long-term observational data from terrestrial ecosystems. Kevin McCann and I recently initiated a collaborative research program on spatial food web dynamics of phytoplankton and zooplankton populations in massive aquatic mesocosms in the new Limnotron facility at the Biodiversity Institute of Ontario. Initial experiments relate to resource- vs predator- and ratio-dependent functional and numerical responses, responses of predator and algal populations to pulsed versus continuous nutrient influx, resource- and density-dependent diffusion patterns by zooplankton and phytoplankton, and spatial pattern formation in relation to population fluctuations. An ongoing applied research interest relates to sustainable harvesting of fish and mammal populations. Key questions relate to long-term stability of harvested populations due to dynamic variation in harvester effort, effects of bioeconomic dynamics on long-term stability of fish stocks and prices, and spatial processes in harvested populations with and without no-harvest reserves.

近期论文

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Holdo, R. M., Fryxell, J. M., Sinclair, A.R.E., Dobson, A., Holt, R. D. (2011), Predicted Impact of Barriers to Migration on the Serengeti Wildebeest Population. PLoS ONE 6(1): e16370. doi:10.1371/journal.pone.0016370 Fryxell,J.M., Packer,C., McCann, K., Solberg,E.J., Saether, B., Resource Management Cycles and the Sustainability of Harvested Wildlife Populations. Science 328, 903 (2010) Dalziel, B.D., Morales, J.M., Fryxell, J.M., Fitting Dynamic Models to Animal Movement Data: The Importance of Probes for Model Selection, a Replay to Franz and Caillaud. The American Naturalist,Vol. 175, 6, June 2010 Sinclair, A.R.E., Metzger, K., Brashares, J.S., Nkwabi, A., Sharam, G., Fryxell, J.M., Trophic Cascades in African Savanna: Serengeti as a Case Study, Tropic Cascades (Terborgh et all, eds), Island Press, pages 255-274, (2010) Yott, A., Rosatte, R. Schaefer, J.A., Hamr,J., Fryxell, J.M., Movement and Spread of a Founding Population of Reintroduced Elk, (Cervus elaphus) in Ontario, Canada, Society for Ecological Restoration International, doi: 10.1111/j.1526-100X.2009.00639.x Smith-Owen, N., Fryxell, J.M., Merrill, E.H., Foraging Theory Upscaled: The Behavioural Ecology of Herbivore Movement. Phil. Trans. R. Soc. B (2010) 365, 2267-2278, doi: 10.1098/rstb.2010.0095 Johnson, C. A., Fryxell, J.M., Thompson, I.D., Baker, J.A. (2009). Mortality risk increases with natal dispersal distance in American martens. Proc. R. Soc. B. 276, 3361-3367 Holdo, Ricardo M., Holt, Robert D., Fryxell, John M. Opposing Rainfall and Plant Nutritional Gradients Best Explain the Wildebeest Migration in the Serengeti. The American Naturalist, Vol. 173 (4), April 2009 Holdo, Ricardo, Holt, Robert D, Fryxell, John M. Grazers. browsers, and fire influence the extent and spatial pattern of tree cover in the Serengeti. Ecological Applications, 19(1), 2009, pp. 95-109 Fryxell et al. (2008) Multiple movement modes by large herbivores at multiple spatiotemporal scales. PNAS 105:19114-19119