Physical disturbance by recovering sea otter populations increases eelgrass genetic diversity.

Most knowledge regarding the role of predators is ecological in nature. Here, we report how disturbance generated by sea otters () digging for infaunal prey in eelgrass () meadows increases genetic diversity by promoting conditions for sexual reproduction of plants. Eelgrass allelic richness and genotypic diversity were, respectively, 30 and 6% higher in areas where recovering sea otter populations had been established for 20 to 30 years than in areas where they had been present <10 years or absent >100 years.