How does plant functional diversity modulate the response of mountain ecosystem processes to climate change? (NERC EAO DTP)

Project outline: Evidence is mounting that climate change in mountain areas is 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 (carbon dioxide and methane), 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, and, as far as we know, has not been studied in high mountain ecosystems that are especially vulnerable to climate change. This project aims to redress by experimentally testing the individual and interactive effects of vegetation change and climate warming on soil and ecosystem processes, including nutrient cycles and greenhouse gas fluxes, and identify the mechanisms involved, especially concerning the role of the soil microbial community.

Studentship goals: The aim of this studentship is to experimentally test how simultaneous changes in vegetation composition and climate impact the functioning of microbial communities in relation to carbon and nutrient cycling in high mountain ecosystems. The student will test the hypothesis that changes in vegetation modulate the response of soil biogeochemical cycles to climate change, and that this is determined by changes in the composition and functioning of diverse soil microbial communities. This will be tested using a combination of long-term and recently established field experiments in dwarf-shrub dominated mountain ecosystems in northern England, combined with state-of-the-art approaches to quantify the diversity and activity of microbial communities and processes of carbon cycling in soil. In particular, the student will take field measurements and samples for laboratory processing from a unique vegetation removal (involving removal of shrubs, grasses and mosses in all combinations) and warming experiment at Moor House National Nature Reserve in the north Pennines, which was set up in 2008 (Ward et al. 2013, 2015; Walker et al. 2015, 2016). The student will also establish new experiments in other mountain regions, to test whether responses are general across mountain regions and conduct a series of laboratory tests to disentangle mechanisms involved.

Training: A multi-disciplinary team of scientist, with expertise in soil, plant and microbial ecology, organic and isotope geochemistry and element cycling, will supervise the project. The student will be trained in state of the art methods for measurement of soil microbial communities, using molecular approaches, and for assessing the turnover, composition and fate of carbon and nitrogen in soils, and in statistical methods for assessing data. The student will have access to world-class facilities in the both Soil and Ecosystem Ecology Laboratory http://www.soilecosystemecologylab.manchester.ac.uk and the Williamson Research Centre for Molecular Environmental Science http://www.sees.manchester.ac.uk/our-research/research-centres/wrc/ at The University of Manchester.