New possible complementary approaches to study the responses of terrestrial alpine ecosystemsto climate changes in the MICROPLANTALP project

Climate change (CC) is causing wide alterations in the natural balance, composition, and structure of numerous ecosystems, and alpine regions are among the most vulnerable ones. Soil microorganisms play a pivotal role in the regulation of biogeochemical cycles. A substantial gap exists in the understanding of the biological response to this change at the soil level, due to the untangled plant and microbial activity. The MICROPLANTALP project aims to overcome these limits by integrating two complementary transplantation approaches within a single study, to characterize the responses of an alpine grassland ecosystem (Mont Blanc area, Courmayeur, Italy) under possible CC scenarios. In the first approach, soil monoliths containing native plants, collected at high altitudes (2,500 m a.s.l.), were transplanted to a lower altitude (1,500 m a.s.l.). Photosynthesis and soil respiration were monitored concurrently at the two elevations by automated clear and opaque closed dynamic chambers. In the second transplantation, monoliths collected in the same high-elevation area have been exposed to two different future CC scenarios (increases in temperature and CO2) at the European Ecotron of Montpellier (France) (www.ecotron.cnrs.fr). As a next step, changes in bacterial and fungal communities’ diversity and composition will be studied with a DNA metabarcoding approach. Variations in the metabolic activity of microbial communities will be evaluated through enzymatic activity assays targeting biogeochemical cycle-related enzymes. Specific taxonomic groups and genes associated with these processes will be analyzed using qPCR approaches. The data obtained will be compared and integrated considering above-ground plant growth, carbon fluxes, and soil physicochemical parameters.