Population regulation in snowshoe hare and Canadian lynx: Asymmetric food web configurations between hare and lynx

Abstract

The snowshoe hare and the Canadian lynx in the boreal forests of North America show 9-to 11-year density cycles. These are generally assumed to be linked to each other because lynx are specialist predators on hares. Based on time series data for hare and lynx, we show that the dominant dimensional structure of the hare series appears to be three whereas that of the lynx is two. The three-dimensional structure of the hare time series is hypothesized to be due to a three-trophic level model in which the hare may be seen as simultaneously regulated from below and above. The plant species in the hare diet appear compensatory to one another, and the predator species may, likewise, be seen as an internally compensatory guild. The lynx time series are, in contrast, consistent with a model of donor control in which their populations are regulated from below by prey availability. Thus our analysis suggests that the classic view of a symmetric hare-lynx interaction is too simplistic. Specifically, we argue that the classic food chain structure is inappropriate: the hare is inf luenced by many predators other than the lynx, and the lynx is primarily inf luenced by the snowshoe hare.

Ecology and conservation of lynx in the United States

“…Long-distance dispersal of lynx and other predators during cyclic declines could act as a synchronizing element of the hare cycle (Butler 1953;Lack 1954;Korpimäki and Krebs 1996). In a recent analysis of time series data for hare and lynx, Stenseth et al (1997) suggest that the dominant community linkages are three dimensional for the hare cycles, and two dimensional for the lynx cycles. The hare appears to be regulated from below and above (thus both the vegetation-hare and hare-predator interactions must be considered to understand hare dynamics), whereas the lynx seems to be regulated only from below (thus, for the lynx, the hare-lynx interaction dominates).…”

“…Lynx populations in the taiga exhibit cyclic dynamics with high-amplitude fluctuations Stenseth et al 1997;Chapters 8, 9). There is some evidence that hares (Chapter 7) and lynx (Chapter 8) fluctuate in the south as well.…”

Application of interval iterations to the entrainment problem in respiratory physiology

“…the logistic onedimensional equation for a single species) allows the description of complex dynamical behaviours in population growth modelling in many contexts and several disciplines, such as in biology, economy and social sciences (Schaffer et al 1986;Demongeot & Leitner 1996;Demongeot et al 1997;Stenseth et al 1997;Demongeot & Waku 2005). The case of n-dimensional flows (system of difference equations for n species) will not be treated in the following, but could be considered as a natural generalization of the techniques here proposed.…”

Parameter and Structure Inference for Nonlinear Dynamical Systems

“…The classic example is the Lorenz system [l], intended as a simplified representation of climate variables. Other examples are the human cardiovascular system [2], where the heart-lung oscillations show physiologically important couplings, and predator-prey interactions, where one predator species feeds primarily on a singlc prey species, but WIU, when necessary, feed on others [3]. These last two are examples of an important class of problem where it is the coupling between subsystems which is of scientific importance.…”