The maximum power principle predicts the outcomes of two-species competition experiments

The maximum power principle (MPP) states that biological systems organize to increase power whenever the system constraints allow. The MPP has the potential to explain a variety of ecological patterns because biological power (metabolism) is a component of all ecological interactions. I empirically tested the MPP by reanalyzing three two-species competition experiments by Gause, Vandermeer, and Fox and Morin. These experiments investigated competitive outcomes in microcosms of heterotrophic protists. I introduce metabolic state-space graphs to portray the metabolic trajectories of the communities and show that the steady-state outcomes of these experiments are consistent with the MPP. Winning species were successfully predicted a priori from their status as the species with the highest power when alone. In addition, periods of coexistence, although not predictable a priori, were consistent with the MPP because coexistence states had community-level power that was higher than either species could achieve alone. Thus, the outcomes of all ten trials were the maximum power states, given the options. The results suggest that the maximum power principle may represent a useful energetic organizing principle for communities.