Eco-evolutionary response of complex ecosystems to changing environments

Although ecological and evolutionary dynamics have long been assumed to occur on disparate timescales, many complex ecosystems, especially microbial communities, show rapid adaptation in response to environmental changes. These species with novel phenotypic traits construct new niches, which in turn alters the environment. We explore this eco-evolutionary feedback via a consumer-resource model to account for evolution. Specifically, consumers compete for resources, experience demographic noise, and mutate in a phenotypic trait space. Since the interactions between consumers and resources are asymmetric, the ecosystem relaxes towards a non-equilibrium steady state where the community structure is constantly changing. Drawing from non-equilibrium statistical physics, we analyze the properties of this non-equilibrium steady state and discuss the new phases and behaviors that an ecosystem with concurrent ecological and evolutionary timescales can exhibit.  Furthermore, we investigate the response of a complex community to changes in resource influx and how the rate of adaptation is affected by a time-varying environment.