Size and mobility do matter: a modified scheme of interspecific interactions

Abstract

Interactions among species play a major role in shaping ecological and evolutionary patterns. In natural communities we see myriads of interactions and the great challenge is how to classify them into a finite number of discrete categories. Interspecific interactions are traditionally displayed in a grid according to their outcome (positive, negative or neutral) for each partner. However, this outcome-based framework ignores functional inequality between interacting organisms. The distinction between partners of different “strength” – relative size and/or motility – can be used for modification of traditional outcome framework. Here I have enlarged classic 3 × 3 scheme (designed for classifying interactions between equal partners) by adding strong/weak and host/inhabitant interacting pairs. By using this approach we can formulate explicit verbal definitions for 27 interaction types. Terminology for specific, generic and “umbrella” concepts is discussed. In result we have more detailed and adequate framework that allows, for example, discrimination of interactions that are mingled together in other schemes.