Competition Enables Rapid Adaptation to a Warming Range Edge

Most predictions of how climate warming will affect species ranges ignore species interactions. We tested experimentally if range-edge populations can adapt to warming within competitive communities. Using a model plant species, we found that adaptation to warming range edges was possible only when populations evolved with interspecific competitors. Moreover, competitors enabled the evolution of both high-temperature tolerance (CTmax) and increased thermal performance breadth at the range edge. Yet, competitors limited adaptation at the range core and had no detectable effects on population growth rates at the range edge, suggesting that responses to competition and warming can be cryptic. Our results highlight the urgency of including community context in predicting future range shifts, showing that antagonistic interactions do not necessarily hinder adaptation to climate deterioration. ### Competing Interest Statement The authors have declared no competing interest.