Eco-evolutionary feedbacks in microbial coexistence

Abstract

Species interactions are a hallmark of all ecosystems. Environmental changes can alter how species interact or even whether they interact at all. This can affect the tipping point between coexistence and competitive exclusion, which can have cascading effects on community composition, and ecosystem function. Microbes interact in surprisingly complex ways; their small size, simple genomes, and fast generation times make them excellent tools for studying such eco-evolutionary processes in real time. I use a microbial model system composed of flocculant and non-flocculant strains of Kluyveromyces lactis to investigate how resource availability influences the maintenance and evolution of their coexistence. First, I reduce population density during flocculation to establish the effects of interaction frequency on community composition. Second, I analyze how changes to resource availability lead to deviations from these expectations. This work contributes to broader ecological principles by describing how species interactions and differential responses to environmental change affect community composition.