Rudy Boonstra
University of Toronto (CAN)
Title
The Snowshoe hare cycle in the Canada's Boreal Forest: The Sublethal effects of High Predation Risk
Summary of the talk
The boreal forest wreaths the top of Canada like a green halo, covering some 5,000,000 square kilometers.
Every 10 years, the dominant herbivore in this forest – the snowshoe hare – cycles like clockwork.
In the southwestern Yukon, their numbers peak at about 200-300 per square kilometer and then rapidly declines over
2-3 year to about seven per square kilometer. The cause of the hare decline is that their predators - Canada lynx, coyotes,
and great horned owls – kill virtually all of them.
A major puzzle in this repeated cycle is why the subsequent low phase for hares then lasts between two and four years when the
predators have almost all disappeared and food supplies have good.
This talk will explore the impacts of the high predation risk on the physiology of the stress axis in hares and the role this plays
in long term demographic changes through maternal effects. The talk will also present preliminary evidence on the molecular changes
in brain organization of the hippocampus because of the effects of chronic predation stress.
Brief CV
I am a full professor at the University of Toronto at Scarborough, with a primary departmental appointment in Zoology and a cross-appointment in Physiology (Faculty of Medicine).I am also the Vice-Principal, Research.
I came to U of T in 1977. I was born in the Netherlands, raised in Alberta, took my undergraduate degree at the University of Calgary, my Ph. D. with Dr. Dennis Chitty at the University of British Columbia (in Population Ecology) and continued on at UBC for a one-year post-doctoral fellowship with Dr. A.R.E. Sinclair, before moving to U of T.
My research focus has been on population regulation in mammals, with a particular emphasis on northern cyclic mammals. Thus, it was primarily on population regulation of natural populations. However, my research direction has changed to focusing on endocrinology of natural populations of mammals (particularly the Stress Axis) and now to neuroendocrinology, with an emphasis on why all sexual organisms get old and die: i.e. aging and neurogenesis. Most of my research publications (116 published, 1 book) have been in ecology, evolution, and behavior, but an increasing proportion are now physiological.
I continue to do my field work thoughout Canada (Yukon, Alberta, Ontario) and have also worked in Australia and Norway. I am now collaborating with colleagues in physiology on brain mechanisms. I have supervised Masters and Ph. D students.
Relevant Papers
- Boonstra, R. 2004. Coping with changing northern environments: the role of the stress axis in birds and mammals.
Integrative and Comparative Biology 44:95-108.
- Clinchy, M., L. Zanette, R. Boonstra, J.C. Wingfield and J.N.M. Smith. 2004. Balancing food and predator pressure induces chronic stress in songbirds.
Proceedings of the Royal Society (London). Series B 271: 2473 – 2479.
- Boonstra, R., C.J. McColl, and T.J. Karels. 2001. Reproduction at all costs: how breeding compromises the stress response and survival in male Arctic Ground Squirrels.
Ecology 82:1930-1946.
- Krebs, C.J., R. Boonstra, S. Boutin, and A.R.E. Sinclair. 2001. What drives the ten-year cycle of snowshoe hares?
Bioscience 51: 25-35.
- Boonstra, R., D. Hik, G.R. Singleton, and A. Tinnikov. 1998. The impact of predator-induced stress on the snowshoe hare cycle.
Ecological Monographs 68: 371-394.
