My research is broadly concerned with understanding the role of interactions between plant and soil communities in regulating the structure and function of terrestrial ecosystems, and their response to global change. A particular focus of my research is ecosystem nitrogen and carbon cycling and I work in a range of ecosystems, from tropical forests, to grasslands, and alpine and arctic tundra. Specific themes and examples of current research include:
Plant traits and ecosystem processes: A key goal of my research is to better understand of how plant traits impact on soil biological communities and the processes of carbon and nitrogen cycling that they drive. Much of this work is being done in grasslands, and includes studies done at the individual plant, field, and landscape scale. The ultimate aim of this research is to develop a trait-based framework for understanding how changes in plant functional diversity, for example resulting from land use change, influence soil microbial communities and the processes that underpin the ecosystem services of soil carbon storage and efficient nitrogen cycling. We are also using this knowledge to better manage grassland diversity for carbon storage.
Soil biodiversity and ecosystem function: Soil biological communities are extremely species rich and a key goal of my research, for several years, has been to better understand how changes in the diversity and composition of soil communities influence ecosystem processes. A key theme of this research is to advance understanding of how trophic interactions in soil control nutrient supply to plants, and how changes in food web composition impact on carbon and nitrogen cycling. This research also extends to understanding factors that regulate soil biodiversity at different spatial and temporal scales, and to optimising land management to reap benefits from the living soil.
Plant-soil interactions and climate change: Climate change impacts on biogeochemical cycles via a variety of mechanisms involving interactions between plant and belowground communities. My research is aimed at understanding the mechanisms by which climate change impacts on plant-soil interactions and the carbon cycle at different spatial and temporal scales, ranging from short term impacts on the physiology and activity of aboveground and belowground biota, to longer term impacts caused by changes in community composition. An ultimate goal is to use this research to inform on land management options for climate mitigation through the sequestration of carbon in soil.
Herbivore impacts on terrestrial ecosystems: An ongoing interest of mine, since my PhD, is the study of how large grazing animals influence the structure and function of terrestrial ecosystems, with a focus on soil biological properties and nutrient cycling, and, more recently, carbon dynamics. Much of this work has been done in mountain grasslands that are grazed by sheep, but more recently we have been studying effects deer browsing in native forest ecosystems in the Scottish Highlands and reindeer in the high arctic.
Bardgett, R.D. & Wardle, D.A. (2010) Aboveground-Belowground Linkages: Biotic Interactions, Ecosystem Processes, and Global Change. Oxford Series in Ecology and Evolution, Oxford University Press.