Habitat Filtering and Phylogenetic Interactions Structure Lake Fish Communities

Identifying which biotic and abiotic factors limit species distributions and how they impact community structure is vital to community ecology research. An often overlooked area of research is the role that phylogenetic relatedness of species relative to the  community species composition. Phylogenetic structure may demonstrate shared traits that promote coexistence of closely related species under certain environmental stressors (i.e. environmental filters) but can also demonstrate high levels of competitive exclusion between closely related species leading to phylogenetic overdispersal under other conditions. We developed a phylogenetic tree using Bayesian inference with mitochondrial genes COI and CytB of Ontario lake fishes to analyze the phylogenetic signal in fish communities across a variety of lakes to help disentangle these opposing viewpoints. Our results show that in these lake communities, there are environmental stressors that can act as habitat filters and that these stressors can have non-random effects in terms of community phylogeny. This non-random selection leads to phylogenetically clustered communities and shows that phylogeny can be highly informative when describing selective pressures and community structure in lake fishes.