Community Rescue in Experimental Metacommunities. Community_Rescue

The conditions that allow biodiversity to recover following severe environmental degradation are poorly understood. We studied evolutionary rescue in metacommunities of soil microbes adapting to a herbicide. The metacommunities occupied a landscape of crossed spatial gradients of the herbicide and a resource, while their constituent communities were either isolated or connected by dispersal. The spread of adapted communities across the landscape and the persistence of communities when that landscape was degraded were strongly promoted by dispersal, while the capacity to adapt to lethal stress was also related to community size and initial diversity. After abrupt and lethal stress, community rescue was most frequent in communities that had previously experienced sub-lethal levels of stress and had been connected by dispersal. Community rescue may allow productivity and biodiversity to recover from severe environmental degradation.