Tree-Soil-Microbiome Interplay under Drought. When trees die: Understanding how plants and microbes interact and influence soil biogeochemical processes

Ma­jor drought im­pacts are to be ex­pec­ted in sev­eral European inner-Alpine val­leys, such as the Rhone val­ley of Switzer­land, where cli­matic con­di­tions have shif­ted to­wards in­creas­ing sum­mer droughts due to higher evapo­tran­spir­a­tion and chan­ging sea­son­al­ity of pre­cip­it­a­tion. In the Rhone val­ley of Switzer­land, these con­di­tions are trig­ger­ing cas­cad­ing ef­fects lead­ing to the die­back of Scots pine (Pinus sylvestris L.) trees, which dom­in­ate the forest stands in the driest parts of the val­ley. In par­al­lel to the wide­spread re­duc­tions in tree growth and in­creased mor­tal­ity which have been doc­u­mented, the im­pact of wa­ter lim­it­a­tion on the soil mi­cro­bi­ome could have prom­in­ent ef­fects on the cyc­ling of car­bon and ni­tro­gen. In this pro­ject we as­sess how wa­ter lim­it­a­tion acts syn­er­gist­ic­ally on the bio­lo­gical in­ter­play between Scots pine trees and as­so­ci­ated soil mi­cro­bial com­munit­ies, and con­sequently in­flu­ences car­bon and ni­tro­gen dy­nam­ics over time.