Plant-microbial linkages underpin carbon sequestration in contrasting mountain tundra vegetation types

Tundra ecosystems hold large stocks of soil organic matter (SOM), likely due to low temperatures limiting rates microbial SOM decomposition more than those accumulation from plant primary productivity and necromass inputs. Here we test the hypotheses that distinct tundra vegetation types their carbon supply characteristic rhizosphere microbes determine cycling independent temperature. In subarctic Scandes, used a three-way factorial design with paired heath meadow at each two elevations, combination type elevation subjected during one growing season either ambient light (i.e., productivity), or 95% shading reduced productivity). We assessed potential above- belowground ecosystem linkages by uni- multivariate analyses variance, structural equation modelling. observed direct coupling between community composition function, which underpinned ecosystem's for storage. Greater supported higher biomass nitrogen immobilisation, lower mass-specific enzymatic activity humification. Congruently, larger in sustained fungal-dominated communities, were less substrate-limited, invested into mineralisation, owing greater carbon-use efficiency (CUE). Our results highlight importance characteristics type), via effects on size, structure physiology, as essential drivers turnover. The here documented concerted patterns functioning is strongly supportive using surrogates assessing storage its evolution under climate changes.