Large-scale changes in global wetlandscape function - do we know them?

The global ecosystem services provided to humans by wetlands have been valued among the top three biomes in the world, for instance exceeding the total value of terrestrial forests and coral reefs. Various aspects of global change may however affect wetland functionality, and thereby also the associated services of wetland ecosystems and their economic values, including changes in climate, water use, land use, demographic influences, and other global change drivers. Quantification and projection of such global services thus require corresponding large-scale understanding of the functionality of wetlandscapes (landscape-catchment systems with multiple wetlands) and its possible alteration under global change. A key question for global change research is if the large-scale impacts on wetlandscapes and their ecosystem services and associated values are assessed and evaluated at relevant scales. We here analyze long-term hydroclimatic data, expert judgments for 21 wetlandscapes across the world, and 21,433 wetland-related scientific articles to investigate if and how ongoing research actually addresses large-scale dynamics. From this analysis, hydroclimatic change emerges as a key change driver and coastal protection emerges as a key function that both remain largely uninvestigated in relation to such large-scale wetlandscape aspects. Overall, the present results identify essential research gaps for a range of water-related drivers of global change and their relations to the large-scale function and service potential of wetlandscapes.