Network for Biological Invasions and Dispersal Research

MITACS Seminar at the University of New Brunswick, Fredericton

Wednesday, 20 February, 2008,

Rebecca Tyson

of the University of BC, Okanagan

will speak on

Modelling the Dynamics of the Canada Lynx and Snowshoe Hare Population Cycle

2:00 PM, KED B015, University of Ottawa

Abstract: The population cycle of the showshoe hare has been a focus of scientific interest for the past century. These populations are characterized by striking high amplitude multi-year cycles with a period of 8-11 years. For many years, the showshoe hare cycle was thought to be a classical predator-prey interaction between the hare and the lynx. Existing models have shown the importance of the predator-prey interaction, and have approximately captured many traits of the cycle. None however, have been able to simultaneously capture all of the five main cycle characteristics, namely the maximum population, minimum population, cycle amplitude and cycle period for both the lynx and hare. In particular, models generally predict minimum hare densities that are much higher than those observed in the field. Our first objective is to develop a model of the lynx-hare population dynamics that generates cycles with realistic boreal values for all five cycle probes mentioned above. We then use this model to investigate possible sources of the difference in dynamics between northern and southern hare populations: the northern populations exhibit large multiannual cycles, while the southern populations exhibit little to no cycling. In particular, we study the effect of generalist predation and of habitat fragmentation.