Structural variation across food webs as a measure of biodiversity at the ecosystem level

Abstract: Biodiversity can be measured in several ways and on several levels. In this study a framework is developed to use topological differences in the food webs describing ecosystems to quantify differences between ecosystems. This is then used in an attempt to describe biodiversity at the ecosystem level. Empirical food webs were analysed to find out if distance between systems in a multidimensional space where network characteristics are used as axes can be used to give an indication of variation among the systems. To test if some class of systems is more varied the systems were classified in several ways, according to type of system, location of system and size of the food web describing the system. Among the analysed systems some classes had a larger proportion of large distances, which indicates that there were more dissimilar systems within those classes. The classes showing larger variation were lakes, freshwater systems, temperate systems and systems with a larger number of nodes.