How competition affects evolutionary rescue

摘要

Populationssfacing novel environments can persist by adapting. In nature, the ability to adapt and persist will depend on interactions between coexist-ing individuals. Here we use an adaptive dynamic model to assess how the potential for evolutionary rescue is affected by intra- and interspecific com-petition. lntraspecific competition (negative density-dependence) lowers abundance, which decreases the supply rate of beneficial mutations, hinder-ing evolutionary rescue. On the other hand, interspecific competition can aid evolutionary rescue when it speeds adaptation by increasing the strength of selection. Our results clarify this point and give an additional requirement: competition must increase selection pressure enough to overcome the nega-tive effect of reduced abundance. We therefore expect evolutionary rescue to be most likely in communities which facilitate rapid niche displacement. Our mnodel, which aligns to previous quantitative and population genetic models in the absence of competition, provides a first analysis of when competitors should help or hinder evolutionary rescue.