Eco-evolutionary interactions with multiple evolving species reveal both
antagonistic and additive effects.
Abstract
Most eco-evolutionary research focuses on ecological effects of
single-species evolution. We therefore know little of eco-evolutionary
dynamics when multiple species evolve simultaneously. We quantified
evolution-mediated ecological effects in communities equivalent in
genetic diversity and starting biomass, but different in selection
background (heatwave exposure) of one or all four zooplankton species
(three Daphnia and one Scapholeberis species). We observed
transient eco-evolutionary effects that differed depending on which
species in the community had evolved. Evolution did not always lead to
higher abundances of the evolved species. Indirect effects on species
abundances caused by evolution of another species could be as strong as
direct effects mediated by its own evolution. The cumulative effect of
evolution in multiple species was antagonistic for community composition
and grazing pressure but additive for community-wide biomass. Our
results imply that focusing on single species’ evolutionary effects on
ecology may lead to unreliable predictions when multiple species evolve
simultaneously.