Faster growing and more functionally diverse: global change alters functional trait composition of mountain plant communities in the European Alps

Understanding how global change reshapes mountain plant communities is essential for predicting biodiversity and ecosystem function in a warming world. Using resurvey data from over 1,400 alpine and subalpine vegetation plots across the European Alps, we show that community-weighted means of key functional traits – specific leaf area, leaf nitrogen, and seed mass – have increased significantly over recent decades, reflecting a widespread shift toward more resource-acquisitive strategies. Yet trait–environment relationships along the elevational gradient have remained remarkably stable, pointing to persistent abiotic filtering. Contrary to expectations, plant height declined slightly, and increases in seed mass were confined to lowland communities mainly, likely due to edaphic constraints and reduced uphill dispersal by large herbivores, respectively. These findings indicate that global change is reshaping the functional structure of montane plant communities by shifting baseline trait composition while leaving the underlying elevational filters largely intact.