Cultural Eutrophication Mediates Context-Dependent Eco-Evolutionary Feedbacks of a Fish Invader

Eco-evolutionary dynamics are typically depicted as direct reciprocal interactions between ongoing trait change and ecological change, but environmental context is increasingly recognized for its potential role in mediating evolution's effects on ecology and vice versa. Indeed, environmental context might be considered a third major player within any given eco-evolutionary dynamic, which may at times be determined by strong external drivers but also potentially dynamically remodeled by feedbacks from evolution's effects on ecology. In this study, we test for the environmental context effects of lake trophic state, a condition that is strongly shaped by both external and internal processes of aquatic systems. Specifically, we test whether and how oligotrophic or eutrophic conditions influence the community and ecosystem effects of recent phenotypic divergence of invasive White Perch (Morone americana) populations. Using a factorial treatment design, perch from oligotrophic and eutrophic lake sources were stocked into oligotrophic and eutrophic mesocosms to quantify their effects on pelagic and benthic communities as well as nutrient limitation and system productivity. Perch source influenced benthic invertebrates, primary production, and nutrient limitation, supporting the presence of a phenotype-to-ecology feedback. Importantly, effect size modeling revealed that these perch source effects varied with background trophic conditions and across pelagic versus benthic compartments, supporting context dependence. The specific context-dependent effects we observed suggest that remodeling of environmental context within eco-evolutionary dynamics might facilitate alternate stable state transitions initiated by cultural eutrophication.