A horizon scan for Arctic coastal biodiversity research: understanding changes requires international collaboration.

Arctic coastal biodiversity faces increasing threats from anthropogenic activities and climate change. However, the effects on biodiversity are still poorly understood, hindering actions aimed at mitigating the impacts at a pan-Arctic scale. We present the results of a horizon scan that provides a road map to address knowledge gaps on the influence of anthropogenic activities, from increased shipping and harvesting to consequences of climate change including increasing temperatures, cryosphere loss, and freshwater runoff. Predictions on ecological change, species range expansions, and anthropogenic impacts on Arctic coasts are hampered by the lack of biodiversity data and scarcity of biological long-term monitoring programs. Filling these knowledge gaps will require coordinated international efforts and standardized experiments across the diverse ecosystems characterizing the Arctic.