Bioregions are predominantly climatic for fishes of northern lakes

Aim: Recurrent species assemblages integrate important biotic interactions and joint responses to environmental and spatial filters that enable local coexistence. Here, we applied a bipartite (site-species) network approach to develop a natural typology of lakes sharing distinct fish faunas and provide a detailed, hierarchical view of their bioregions. We then compared the roles of key biogeographic factors to evaluate alternative hypotheses about how fish communities are assembled from the regional species pool.

Location: Ontario, Canada and the Upper Midwest, USA.

Time period: 1957–2017.

Major taxa studied: Freshwater fishes.

Methods: Bipartite modularity analysis was performed on 90 taxa from 10,016 inland lakes in the Southwestern Hudson Bay, Mississippi River, and St. Lawrence River drainages, uncovering bioregionalization of North American fishes at a large, subcontinental scale. We then used a latent variable approach, pairing non-metric partial least-squares structur...