Qualitative Stability in Model Ecosystems

Abstract

We discuss deductions that can be made as to the stability of multispecies communities, knowing only the structure of the food web, i.e., knowing only the signs of the elements in the interation matrix. Systems which are stable in these circumstances are called qualitatively stable and have been treated in economic and other contexts. The discussion touches upon general aspects of the relation between complexity and stability in multispecies systems, and in particular suggests that on stability grounds predator—prey bonds should be more common than mutualistic ones. This result is not intuitively obvious, but is a feature of many real—world ecosystems.