The propagation and some implifications of environmental noise in ecological
food webs
Jörgen Ripa
Dept of Theoretical Ecology, University of Lund, Sweden
Abstract
I have studied the effects of environmental noise in ecological food webs
through linear analysis. My main interests were on spectral characteristics of
population dynamics and the propagation of environmental disturbances through
food webs.
My results show that a simple linear analysis of a stochastic food web model
can tell a great deal about the models dynamic behaviour and the relative
responses to noise, entering the foodwebs at different trophic levels. These
results turned out to be general and robust, even when I analysed a linear
approximation of a nonlinear model. One interesting feature of stochastic food
web models is the possibility of sustained oscillations, even though the
deterministic equivalent model has a stable equilibrium.
I also found a general and very simple rule concerning two-species food webs
and their responses to external noise.