Abstract ID: 3.13430 | Accepted as Poster | Requested as: Poster | TBA | TBA

Snowbeds are particularly sensitive to global warming, which leads to reduced snowfall and shorter snow cover durations, potentially affecting ecosystem functions performed by the soil microbiota. However, the relationship between aboveground and belowground alpine ecosystems remains largely understudied. We have compared soil microbial (fungal, bacterial and archaeal) communities under snowbed vegetation assigned to Salicion herbaceae with those under either i) the surrounding typical alpine grassland (Caricion curvulae) or ii) transitional plant communities (i.e. previous snowbeds where encroachment of more competitive grassland plant species is taking place), at two distant sites in Italy (Monte Rosa Massif in Piedmont and Passo Gavia in Lombardy) at the same elevation (approx. 2700 m asl). At both sites the soils are acidic and exhibit a carbon-rich A horizon, with a slightly higher degree of soil development in Passo Gavia, where some evidences of podsolization are observed. Metabarcoding of the ITS2 and 16S region amplified from 277 topsoil samples collected at three timepoints (winter, early and late summer), resulting in 4473 and 13,764 OTUs, respectively, indicated significant differences in soil microbial assemblages between the two sites. Despite such regional differences, at both sites vegetation shifts were tightly paralleled belowground (aboveground vegetation being more influential on microbial communities than seasonal variation). The interconnected changes in aboveground plant communities, soil properties and soil microbial communities serve as indicators of broader ecosystem responses to global warming.