Abstract ID: 3.12346 | Accepted as Talk | Poster | TBA | TBA

Shrub encroachment is a global process that has received increasing interest amongst researchers due to its consequences in ecosystem functions. While there is increasing evidence of the impacts of shrub encroachment in plant communities and biogeochemical cycles, the effects of shrub encroachment on soil microbial communities is still not fully understood. While some studies have found changes in the microbial composition in shrub encroached subalpine grasslands, to our knowledge there is no study on the direct or indirect effects of the changes of plant community traits on soil microbial communities in these ecosystems in the Alps. We hypothesize that changes in the quality of plant community tissues with increasing shrub density (i.e. higher recalcitrant compounds with lower decomposition rates) have an indirect effect on soil fungal communities. We conducted our study in two different locations in the European Alps: Lautaret (France) and Stubai Valley (Austria). We collected plant, soil and root samples in a total of 60 plots of 10 x 10 m along a gradient of increasing shrub biomass. We calculated community weighted means of plant functional traits, we conducted soil biochemical analysis and used high-throughput sequencing of ITS1 to calculate relative abundances of fungal functional groups in root and soil samples. Our preliminary results show lower arbuscular mycorrhiza fungi and higher ericoid mycorrhiza fungi relative abundances with increasing shrub biomass, related to changes in pH and soil carbon:nitrogen ratio respectively. Our results also show increasing trends of pathotrophs, saprotrophs and endophytes with increasing shrub biomass. Our data suggests that the presence of shrubs alters the relative abundances of fungal functional communities, specially the symbiotroph fungi, and results in changes of fungal functional diversity, which may result in changes in ecosystem functioning and have implications in the management of subalpine grasslands.