Abstract ID: 3.12315 | Accepted as Talk | Talk | TBA | TBA

In the future, earlier snowmelt and frequent summer droughts are expected to impact alpine grassland. We will present results from a manipulative experiment in the Swiss Alps at 2500 m a.s.l. (set-up in 2016 for snow manipulation and 2017 for drought) in which annually recurring treatments of advanced and delayed snowmelt were combined with 5- and 10-week summer droughts by rain-out shelters (2.5 m x 3m). There, aboveground biomass of forbs and graminoids was substantially reduced by recurrent 10-week drought, while the dominant sedge Carex curvula remained unaltered. Yet within functional groups, variable responses of the different plant species to the treatments were observed.
In these environments where nutrient limitation may occur, certain plants may strongly rely on soil microorganisms such as mycorrhizal fungi, while others including the dominant sedge have different strategies that may involve other microbial partners. We therefore now ask whether these species-specific responses, in particular to drought, are correlated with changes in soil microbial communities. Using metabarcoding, we will present the response of soil bacterial and fungal communities to snow manipulation and summer drought. These analyses will be combined with the assessment of root colonisation by mycorrhizal fungi and dark septate endophytes.