Abstract

Although ecological theory has historically focused on negative interactions among populations, like competition and predation, ecologists and conservation biologists highlight the significance of interdependence. It is not clear, however, what is asserted in the causal hypothesis that one population is interdependent on others. This essay argues that the most informative causal regularities for representing dependencies are those connecting populations through environmental constraint variables. Interdependence among populations can thus be understood as constraint-mediated dependency relations connected in a circuit.