Before revision:  We show that  the presence of environmental feedbacks, URLanisms can produce new resources in addition to depleting them, violates the global MEPP. However, even in the presence of such feedbacks, a weaker, local version of the MEPP still applies in a limited region of resource space. We show that the MEPP framework is consistent with classic experiments on competition for substitutable resources in herbivorous zooplankton and propose new experiments for testing MEPP directly .
After revision:  We show that the equilibrium state minimizes the perturbation of the environment induced by the presence of the competing species, subject to the constraint that no species has a positive net growth rate. We use this "minimum environmental perturbation principle" to make new predictions for eco-evolution and community assembly, and describe a simple experimental setting where its conditions of validity have been empirically tested .