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Many species exhibit high‐amplitude, extinction‐prone cycles, for instance due to resource enrichment (called the paradox of enrichment). How do such species manage to persist? One possibility is metapopulation dynamics, but it is unclear if these can mitigate the paradox of enrichment. The paradox of enrichment might increase local population extinction rates, and might also increase the spatial synchrony of population fluctuations because population cycles are easily synchronized by even low rates of dispersal. Spatially‐synchronous population fluctuations would leave no scope for rescue effects, and spatially‐synchronous local extinctions would leave no source for recolonization. We conducted a protist microcosm experiment to test how dispersal and enrichment affect the persistence of predator–prey metapopulations by altering spatial synchrony. We assembled 54, 4‐patch metapopulations of the protist predator Euplotes patella and its protist prey Tetrahymena pyriformis. Each metapopulation experienced one of nine dispersal rates, crossed with one of six enrichment levels. We tested the effects of enrichment and dispersal on predator–prey cycle amplitude, predator population extinction risk, spatial synchrony of predator population fluctuations, and predator metapopulation persistence time. Enrichment increased predator–prey cycle amplitude but had no detectable effect on population extinction risk. Dispersal had no effect on predator–prey cycle amplitude. Spatial synchrony increased with enrichment and dispersal. Metapopulation persistence decreased with enrichment and spatial synchrony. We conclude that increasing enrichment reduced metapopulation persistence primarily by increasing spatial synchrony of local extinctions, rather than by increasing their frequency. These results highlight the importance of synchrony‐preventing mechanisms for metapopulation persistence. [ABSTRACT FROM AUTHOR]

Predicting the ecological and evolutionary trajectories of populations in multispecies communities is one of the fundamental challenges in ecology. Many of these predictions are made by scaling patterns observed from pairwise interactions. Here, we show that the coupling of ecological and evolutionary outcomes is likely to be weaker in increasingly complex communities due to greater chance of life‐history trait correlations. Using model microbial communities comprising a focal bacterial species, Bacillus subtilis, a bacterial competitor, protist predator and phage parasite, we found that increasing the number of enemies in a community had an overall negative effect on B. subtilis population growth. However, only the competitor imposed direct selection for B. subtilis trait evolution in pairwise cultures and this effect was weakened in the presence of other antagonists that had a negative effect on the competitor. In contrast, adaptation to parasites was driven indirectly by correlated selection where competitors had a positive and predators a negative effect. For all measured traits, selection in pairwise communities was a poor predictor of B. subtilis evolution in more complex communities. Together, our results suggest that coupling of ecological and evolutionary outcomes is interaction‐specific and generally less evident in more complex communities where the increasing number of trait correlations could mask weak ecological signals. [ABSTRACT FROM AUTHOR]