Spatial heterogeneity, functional response and predator-prey dynamics (2008-)

Cooperation Partners: Department of Ecology, Environement, and Geosciences, UmeƄ University

Studies of mathematical models and simplified experimental ecosystems suggest that many predator-prey interactions are inherently
unstable. This begs the question: How is diversity maintained in nature? It is widely believed that spatial heterogeneity is the answer.
The link between heterogeneity and stability is, however, poorly understood. We have therefore developed a general framework,
moment approximation, which can be used to analyze the role of heterogeneity. It combines models parameterized in homogeneous
systems with field measurements of heterogeneity.

In this work we have identified four research questions that require further research:

1) When measuring heterogeneity it is necessary to consider the resolution of the processes generating non-linearities. In lab-experiments we will quantify the process resolution associated with variance and covariance effects on the functional response.

2) There are no generic models for mean-covariance relationships in predator-prey systems. We will propose such models based on deduction and empirical data.

3) We do not understand the relationship between movement behaviours and covariance dynamics.
This relationship will be studied in spatial models.

4) Initial results show that moment approximation can be a useful tool for analysis of empirical systems with complex spatial dynamics. The generality of this result will be tested by applying moment approximation to natural systems with complex dynamics.