A study by Thorsten B. H. Reusch, Anneli Ehlers, August Hämmerli, and Boris Worm shows that genotypic diversity can enhance ecosystem recovery after climatic extremes, even in species-poor coastal ecosystems. In a field experiment, increasing the genotypic diversity of the seagrass Zostera marina improved biomass production, plant density, and faunal abundance despite near-lethal water temperatures caused by extreme warming. The results suggest that genotypic complementarity, rather than selection of robust genotypes, drives these positive effects. The study highlights the importance of maintaining both genetic and species diversity to enhance ecosystem resilience in the face of increasing climate variability. The findings indicate that genetic diversity can have second-order effects on higher trophic levels, influencing invertebrate fauna. The research underscores the need for conservation strategies that consider genetic diversity, especially in species-poor ecosystems, to support ecosystem functioning and resilience under climate change. The study also emphasizes the importance of understanding short-term ecological responses to rapid global warming, as extreme climate events are expected to become more frequent in the future. The results suggest that genotypic diversity may play a critical role in buffering against climate stress, particularly for sessile species like seagrasses, which cannot rapidly shift their distribution. The study's findings have implications for biodiversity conservation and environmental management, highlighting the need to protect genetic diversity in ecosystems with limited species redundancy.A study by Thorsten B. H. Reusch, Anneli Ehlers, August Hämmerli, and Boris Worm shows that genotypic diversity can enhance ecosystem recovery after climatic extremes, even in species-poor coastal ecosystems. In a field experiment, increasing the genotypic diversity of the seagrass Zostera marina improved biomass production, plant density, and faunal abundance despite near-lethal water temperatures caused by extreme warming. The results suggest that genotypic complementarity, rather than selection of robust genotypes, drives these positive effects. The study highlights the importance of maintaining both genetic and species diversity to enhance ecosystem resilience in the face of increasing climate variability. The findings indicate that genetic diversity can have second-order effects on higher trophic levels, influencing invertebrate fauna. The research underscores the need for conservation strategies that consider genetic diversity, especially in species-poor ecosystems, to support ecosystem functioning and resilience under climate change. The study also emphasizes the importance of understanding short-term ecological responses to rapid global warming, as extreme climate events are expected to become more frequent in the future. The results suggest that genotypic diversity may play a critical role in buffering against climate stress, particularly for sessile species like seagrasses, which cannot rapidly shift their distribution. The study's findings have implications for biodiversity conservation and environmental management, highlighting the need to protect genetic diversity in ecosystems with limited species redundancy.