Contemporary niche theory is a powerful conceptual framework for understanding URLanisms interact with each other and with their shared environment. Herewe show that, for a wide range of modeling assumptions, niche theoryis equivalent to a Minimum Environmental Perturbation Principle (MEPP): ecosystems URLanize into a state that minimizes the collective impact URLanisms on their environment. Different choices of environmental dynamics naturally give rise to distinct dissimilarity measures for quantifying environmental impact. The MEPP allows for the analysis of ecosystems with large numbers of species and environmental factors and provides a new avenue for analyzing ecological invasions. 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 .
Fifty years ago, Robert MacArthur showed that stable equilibria optimize quadratic functions of the population sizes in several important ecological models. Here, we generalize this finding to a broader class of systems within the framework of contemporary niche theory, and precisely state the conditions under which an optimization principle (not necessarily quadratic) can be obtained. We show that conducting the optimization in the space of environmental states instead of population sizes leads to a universal and transparent physical interpretation of the objective function. Specifically, 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 .
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Contemporary niche theory is a powerful conceptual framework for understanding URLanisms interact with each other and with their shared environment. Herewe show that, for a wide range of modeling assumptions, niche theoryis equivalent to a Minimum Environmental Perturbation Principle (MEPP): ecosystems URLanize into a state that minimizes the collective impact URLanisms on their environment. Different choices of environmental dynamics naturally give rise to distinct dissimilarity measures for quantifying environmental impact. The MEPP allows for the analysis of ecosystems with large numbers of species and environmental factors and provides a new avenue for analyzing ecological invasions.
Fifty years ago, Robert MacArthur showed that stable equilibria optimize quadratic functions of the population sizes in several important ecological models. Here, we generalize this finding to a broader class of systems within the framework of contemporary niche theory, and precisely state the conditions under which an optimization principle (not necessarily quadratic) can be obtained.
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conducting the optimization in the space of environmental states instead of population sizes leads to a universal and transparent physical interpretation of the objective function. Specifically,
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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
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