Abstract ID: 3.11574 | Accepted as Talk | Talk/Oral | TBA | TBA

High alpine environments are undergoing significant changes driven by the combined effects of climate change, land-use shifts, and geomorphological processes and their complex interactions. Climate and land-use, such as grazing, alter habitat conditions and affect species composition. Additionally geomorphic disturbances, including debris flows and permafrost degradation as well as glacier retreat drive shifts in vegetation dynamics. Understanding these interactions is crucial for interpreting past and predicting future development.
Therefore, we analysed development of plant communities, total cover, and species number in eleven different study sites of the Central European Alps with different lithology to answer the following main research questions: (i) Which site and climatic variables, and to what extent, influence distribution of plant communities, total vegetation cover, and species diversity? (ii) Does geomorphological disturbance favour specific plant families and does this lead to changes in species composition in general? (iii) What is the role of land-use? To answer these questions, we utilised a Non-metric MultiDimensional Scaling (NMDS) and Structural Equation Modeling (SEM) using 1505 vegetation surveys. Before setting up the SEM we performed a Principal Component Analysis (PCA) to avoid multicollinearity.
The results showed that species composition is highly correlated with (i.e., temperature, wind, precipitation, and solar radiation), length of the snow-free growing season, elevation, distance to glacier, but also permafrost, soil related parameters, land-use, and lithology. The SEM revealed that total cover as well as species number are positively influenced by solar radiation, soil related parameters, and grazing but negatively by precipitation, elevation, distance to treeline, and the community weighted mean of the Landolt indicator value soil reaction. Species number has an indirect positive effect on total cover. Concerning the indirect effects, we could observe a positive effect of elevation on precipitation and for lithology on soil related parameters. Furthermore, we observed that indicator species associated with land-use differ significantly on areas subject to grazing.