Modeling Aboveground–Belowground Interactions

Abstract

Models are powerful tools to capture the complexity of aboveground–belowground interactions in community ecology. Three general model aims can be distinguished: description, explanation, and prediction. These aims are covered by different model types such as conceptual models, graphical models, statistical models, functional–structural models, process-based models, reaction–diffusion models, cellular automaton models, and individual- or agent-based models. The available models of aboveground–belowground interactions always include interactions between root and shoot, and sometimes also trophic, competitive, facilitative, or mutualistic interactions. However, only very few of the existing aboveground–belowground models are community models that incorporate more than three species and more than one type of interaction. Furthermore, spatial relationships are rarely explicitly addressed. Thus, future approaches should (1) improve, simplify, and update current models, (2) extend current models to include more different interaction types and spatial relationships where this is justified by the model question, and (3) employ new modeling techniques such as game theoretical methods or Bayesian network models. Guidelines for model building are given based on the modeling cycle from question through concept, structure, and implementation to analysis and documentation. Close cooperation between empiricists and modelers will promote the success of future models of aboveground–belowground interactions.