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Antarctic biodiversity is much more extensive, ecologically diverse and biogeographically structured than previously thought. Understanding of how this diversity is distributed in marine and terrestrial systems, the mechanisms underlying its spatial variation, and the significance of the microbiota is growing rapidly. Broadly recognizable drivers of diversity variation include energy availability and historical refugia. The impacts of local human activities and global environmental change nonetheless pose challenges to the current and future understanding of Antarctic biodiversity. Life in the Antarctic and the Southern Ocean is surprisingly rich, and as much at risk from environmental change as it is elsewhere.
The past two decades have witnessed a revolution in the approaches used to document patterns in and the functional significance of the diversity of life. Knowledge of the global distributions of organisms now extends to many groups. These include terrestrial plants and animals1, marine taxa2, components of the soil biota3, and, increasingly, microorganisms4. Empirical and theoretical research is verifying the range of mechanisms, including energy and nutrient availability, and historical contingency, that are responsible for these patterns1,2, and the role of diversity in maintaining ecosystem services. New approaches are also revealing rapid changes in diversity across most ecosystems, their often negative implications for the future of the planet, and our struggle to address the problem5.
In tandem, biodiversity research has increased across the Antarctic and Southern Ocean. The growing interest has been driven in part by the realization that any fundamental quest to understand life's diversity requires exploration of the polar regions6,7. But it has also been underpinned by an increasing appreciation of the particular challenges faced by Antarctic species and ecosystems. Climate change8, and economic activity in the form of fishing, tourism, and scientific research itself9,10, are all having impacts on Antarctic diversity. The intricacy of Southern Ocean food webs, best known for the region's iconic seals, penguins, whales and albatrosses, has been further unveiled, highlighting the complexity of the simultaneous impacts of changing climates, sea ice distribution and fisheries on this system11,12. New marine research has also exposed unexpectedly high benthic diversity, including in the deep sea13,14. In terrestrial areas, the diversity of higher plants and animals is relatively low (for example, just two flowering plant species), but the diversity of lichens, bryophytes, invertebrates,...