Ecosystem service proVIsion from coupled plantT and microbial functionAL diversity in managed grasslands

VITAL aimed to address the general hypothesis that the delivery of multiple ecosystem services in semi-natural grasslands, and its vulnerability to changing management, can be explained by the coupling among plant and soil microbial functional diversity, and its impacts on carbon and nitrogen turnover. Overall, using experiments from the individual plant to the field scale at three mountain sites (in the French Alps, Austrian Tyrol and Northern England), we have validated our initial hypothesis that a combination of plant functional diversity and microbial functional parameters determine key mountain grassland ecosystem services. Specifically, we demonstrated that plant and microbial functional parameters are linked, and that they are together associated with key carbon and nitrogen turnover processes underpinning ecosystem services relevant to farmers and regional stakeholders of mountain grasslands, such as grassland production for livestock rearing, regulation of soil fertility and water quality, carbon sequestration and aesthetic and cultural values. We then applied these findings to model ecosystem services at landscape scale. We found that overall, extensification of management promotes plant and associated soil microbial communities linked to slower and more conservative C and N cycling processes, and thus C sequestration and N retention. Scenarios leading to less intensive land use, such as extreme drought, promote C sequestration and N retention at the expense of fodder production and cultural value, thus favouring regional as opposed to local interests. Implementation of political instruments should take into account such trade-offs, along with additional costs and flexibility required to maintain traditional extensive management and its multifunctionality, in terms of ecosystem service delivery.