Revisiting evolutionary rescue in the wild

Environmental change is rapidly occurring. Theoretical and experimental work predicts that evolution can facilitate population persistence in novel and changing environments [evolutionary rescue (ER)]. Recent examples now allow for testing foundational ER hypotheses in wild systems. We propose a more nuanced view for identifying ER by emphasizing the probabilistic role of evolution in reducing extinction risk through the examination of multiple lines of evidence. Using this approach, we identify a range of evolving traits, evolutionary pathways, and population outcomes from ER. Across systems, reducing environmental stress, maintaining genetic diversity, and protecting adaptive alleles can facilitate ER when relevant and desirable. The ways population-level ER might affect higher levels of biological organization and ecosystem resilience likely constitute the next chapter in understanding ER.