Global trends in alpine plant species composition under climate change

Accelerated climate change is increasingly affecting remote alpine ecosystems above the treeline, where warming is predicted to be disproportionately high. These shifts may facilitate the upslope expansion of species from lower elevations, exposing alpine specialists to unsuitable climates and increased competition. Although evidence of climate-driven change in alpine systems is growing, global patterns in alpine plant community composition remain poorly understood. This project leverages the GLORIA (Global Observation Research Initiative in Alpine Environments) long-term monitoring network to quantify trends in alpine vegetation under climate change. We hypothesize that alpine communities are shifting toward more warmth-demanding and widely distributed species, while cold-adapted and endemic species decline, leading to biotic homogenization across regions. We further expect the magnitude of compositional change to be modulated by regional climate velocity, topography, and the size, isolation, and biogeographical history of alpine areas. We will compile and harmonize the standardized GLORIA vegetation data from over 100 regions distributed across the main mountain ranges and ecozones worldwide. We will derive community metrics capturing temperature affinity, range size and beta-diversity, and relate temporal changes in species composition to climatic trajectories using mixed-effects models. By disentangling global trends in alpine vegetation change and their drivers, this work will provide novel, synthetic insights into the ecological consequences of rapid warming in alpine ecosystems.