Modelling biological and resource fluxes in fluvial meta-ecosystems

Meta-ecosystem theory predicts that cross-ecosystem flows of energy, nutrients, and organisms have important implications for local community assembly and ecosystem functioning. Developments in the theory also have the potential to enhance our understanding of biodiversity-ecosystem functioning relationships. Meta-ecosystem theory is particularly well-suited to the study of rivers, because water flow forces strong spatial interrelationships among connected ecosystems. However, models that address flows of both resources and organisms and explicitly link both are lacking. We present a model and associated R-package for cross-ecosystem flows of both resources and organisms that can be used to predict their distribution in river networks, as well as meta-ecosystem functioning. The model incorporates feedbacks between these two crucial components--resource concentrations represent niche dimensions for organisms, modifying the colonisation and extinction dynamics and different locations in the network, and organisms also consume resources, thereby modifying the concentrations that are transported downstream. To illustrate the capabilities of the model, we present an in silico experiment and analysis, as well as providing sample code.