Rapid adaptive evolution to drought in a subset of plant traits in a
large-scale climate change experiment
Abstract
Rapid evolution of traits and of plasticity may enable adaptation to
climate change, yet solid experimental evidence under natural conditions
is scarce. Here, we imposed rainfall manipulations (+30%, control,
-30%) for ten years on entire natural plant communities in two Eastern
Mediterranean sites. Additional sites along a natural rainfall gradient
and controlled selection analyses assessed whether potential responses
were adaptive. In both sites, our annual target species Biscutella
didyma consistently evolved earlier phenology and higher reproductive
allocation in dry plots. This response was adaptive, as it aligned with
theory, corresponding trait shifts along the natural rainfall gradient,
and selection analyses under differential watering in the greenhouse.
However, another seven candidate traits did not evolve, and there was
little support for evolution of plasticity. Our results provide
compelling evidence for rapid adaptive evolution under climate change;
yet, they also call attention to potential constraints for full
adaptation.