Integrating metabolic scaling and coexistence theories

Abstract

AbstractMetabolic scaling and coexistence theories have been pivotal in mathematizing both the energy expenditures and transformations across individuals and populations. Yet, it is unclear how the sustainability of biodiversity depends on metabolic scaling relationships. Here, we provide a tractable and scalable perspective to study how the possibilities for multispecies coexistence (i.e., feasibility) change as a function of the dependence of a population’s metabolism on body size. This integration predicts that, regardless of body size distribution among populations, there is a reciprocal relationship between the scaling exponents defining the dependence of competitive effects and expected carrying capacities on body size. In line with empirical observations, our integration predicts that expected carrying capacities lead to equilibrium biomasses that are independent from body size, and consequently, to equilibrium abundances that are inversely related to body size. We show that this even distribution of equilibrium biomasses increases the possibilities for multispecies coexistence under random environmental perturbations. Additionally, this integration establishes that the possibilities for multispecies coexistence is maximized when no species has an energetic competitive advantage. This integration opens new opportunities to increase our understanding of how metabolic scaling relationships at the individual and population levels shape processes at the community level.