Nils Chr. Stenseth

Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biology, University of Oslo,

 P.O. Box 1050 Blindern, N-0316 Oslo, Norway

Modelling ecological effects of climate fluctuations through the statistical modelling of long-term time series data

This presentation opens with some general reflections on the modelling of ecology-climate interactions, and relating to the statistical modelling of long-term time-series ecological data on the basis of more or less specified ecological models. As part of these introductory remarks, some reflections on non-linear and non-additive effects of climate will be provided.

Then the presentation focuses on to ecological systems:
1.      The Soay sheep off the coast of Scotland (and other ungulates). It is shown that climate fluctuations affect the dynamics of the population non-additively (and possibly non-linearly). This is interpreted as climate affect how individuals within the population interact depends on the current climatic condition. The dynamic consequences of the deduced form of the climate effect are discussed. 

2.      The Hokkaido vole (a small rodent with dynamics resembling the lemming cycles). It is shown that the length of the summer (and winter) season influences the dynamics of the populations and does so non-additively and non-linearly. The dynamics consequences of the deduced effect of changing season length are discussed.

The presentation closes with some general reflections on the interaction between statistical and mathematical modelling of ecological processes and patterns.