Common processes drive metacommunity structure in freshwater fish

AimEnvironmental change affects metacommunity structure both directly-via abiotic factors and dispersal that affect species occurrence-and indirectly-via complex interactions among co-occurring species. We examined how the three main metacommunity factors-environmental conditions, spatial processes and species associations-affect metacommunity structure and whether responses are predictable in real-world systems by using novel methods to disentangle the drivers.LocationEastern Asia, northern Europe and central North America.Time periodContemporary.Major taxa studiedFreshwater fish.MethodsWe used a dataset of freshwater fish species occurrences in temperate lakes in three countries in different biogeographic regions. We analysed co-occurrence patterns by using a joint species distribution model.ResultsWe demonstrated that environmental processes are the main drivers of species' distribution and diversity, suggesting that future climate change (anthropogenic alteration of abiotic factors) will heavily influence the structure of metacommunities. We also showed that spatial processes and species interactions mediated the influence of environmental processes, especially at the lake level.Main conclusionsOur results indicate that ongoing changes in metacommunity structure are modulated not only by the direct impacts of shifting abiotic factors but also by indirect effects of species interactions. Our global analysis indicates that even under the current high rate of environmental change, an identifiable set of underlying processes can be used to predict impacts of this change on metacommunity structure.