Keystone Species Complexes: Quantifying the Cores of Ecosystems

Abstract

Ecological systems are multi-component dynamical systems. Their conservation is traditionally based on protecting their critical components (rare species) one by one. A new, systems-based approach to conservation biology suggests to focus more on important than rare species. Quantifying the relative importance of species is a hard challenge but network analysis can provide support here. Considering indirect effects and positional similarity of species in food webs helps to better understand functional importance. In the talk, I present old and new methods to identify and quantify the most important organisms in ecosystems, illustrating this approach on some case studies. We identify key species (functional groups) and also key sets of species that can be considered a keystone species complex, a functional core of the ecosystem. Finally, I will discuss two main extensions for food web studies (spatial and social).