Understanding transient dynamics of Alpine grasslands under climate warming through the lens of plant-soil interactions – TransAlp

In Alpine grasslands, climate warming and land-use change threaten the structure and dynamics of above- and belowground biodiversity, and their associated ecosystem functions. In our project TransAlp we propose to study short- to long-term effects of these threats by combining transplant experiments covering a decadal time-series of warming responses with a process-based simulation model integrating above- and belowground dynamics. In the transplant experiment, we expose alpine grasslands to 1.5 °C, 3 °C and 4.5 °C of warming along two elevation gradients, add fertilization and grazing sub-treatments, and measure soil and vegetation responses. Expert knowledge and results of the experiment will feed the expansion of the existing vegetation model FATE-HD to integrate key soil tropho-functional groups and interactions between the soil and plant compartment. We will address the following objectives: (1) Analyse the short- to mid-term effects of experimental warming on plant community functioning, soil physico-chemical characteristics and fluxes, and the communities of soil tropho-functional groups (WPs 1-3); (2) Identify the ecosystem components and the dynamic processes that are key to understanding soil-mediated warming and land-use change effects on Alpine grasslands (WP 4); (3) Integrate these key ecosystem components and processes in an existing vegetation model and study temporal dynamics and stability of Alpine grasslands under climate and land-use change (WP 5). Our integrative ecosystem approach will pave the way to better understand and predict the fate of alpine grasslands under environmental changes.