Climate change in mountain areas has been taking place at a much greater pace than in many other ecosystems, with major consequences for ecosystem processes of nutrient and carbon (C) cycling. Mountain areas are also subject to recent and substantial vegetation change, which also has potential to impact ecosystem processes. While it is well known that both climate and vegetation change can individually influence ecosystem processes, evidence is emerging that that they also operate interactively to affect ecosystem functioning. Specifically, we recently discovered that changes in vegetation composition strongly modify both the magnitude and direction of warming effects on peatland greenhouse gas fluxes, suggesting that effects of climate change on ecosystem functioning vary with vegetation change. Aside this finding, our understanding of the potential for interactive effects of vegetation and climate change to influence ecosystem functions, such as C and nutrient cycling, and the mechanisms involved, is sparse. This project is tackling this knowledge gap by experimentally testing how simultaneous changes in vegetation composition and climate impact the functioning of microbial communities in relation to carbon dynamics in peatland ecosystems. The study is based on a long-term vegetation manipulation and warming experiment set up at Moor House National Nature Reserve as part of a NERC funded project in partnership with Nick Ostle at CEH Lancaster.