The complex and systemic establishment of interactions in the ecological communities.

Abstract

The central question in community ecology is explaining how species coexist in a ecological community. In this tradition, individuals belonging to species constitute the biological unit on which observations are concentrated. Individuals produce interactions, and the interactions depend on the individuals. Thus, the individual/population duality and the resulting interactions between these entities are the structuring forces, and the abiotic environment is the conditioning space that, by affecting individuals, becomes another structuring factor. Thus, ecological interactions among individuals in a community emerge as secondary entities resulting as the mere consequence of the properties of individuals (e.g., feeding, fighting, reproduction), and the set of key interactions are candidates for primary causes of community structuring. The modeling of ecological communities is done either by describing their interactions as terms of a dynamical system, links of a network, or rules in agent-based model. However, none of these frameworks can simultaneously i) handle large size systems, while ii) describing interaction mechanisms in detail, and iii) providing ways to compare different models not only based on dynamical results. Here we review the features of these modeling frameworks and introduce the language of reaction networks, native to systems biology, as an alternative method where these three features can be simultaneously achieved. Reaction networks require a paradigm shift as features of species and abiotic environment have the same importance, and the focus is not on the species interactions themselves, but on more general processes of exchange of conditions for the persistence of the whole community.