carbon storage in non-cropped ecosystem soils: toward a global understanding of the impact of grazing and logging. – C-cos2

Carbon sequestration in soil and vegetation represents a valuable lever to mitigate climate change. There is strong evidence that land use impacts the potential of carbon sequestration in soils, either by enhancing carbon storage or release, but the mechanisms remain poorly understood. We argue that in the soil, nutrients and carbon cycles strongly interact, and that these interactions may be key drivers of the carbon storage potential in ecosystems. In the C-cos2 project, we propose to develop a cross-disciplinary approach to better document and understand how nutrients and carbon interact in human-used uncropped ecosystems (forests with logging, natural grassland/savannah with livestock), and to identify ecological conditions, environmental constraints and land use practices that favor carbon sequestration. We will develop an innovative set of tools to quantify proxies of nutrient and carbon cycles and stocks in terrestrial ecosystems. With this set of tools, we will set up empirical assessments of how land use in a wide range of forest and savannah/grassland ecosystems locally affects carbon sequestration. Simultaneously, we will develop a new theoretical framework based on ecological stoichiometry to refine our understanding of how the nitrogen, phosphorus and carbon cycles interact in the vegetation-decomposers-soil system. Our results should contribute to improving global models and projections of carbon storage in terrestrial ecosystems, and should provide innovative, ecosystem-friendly land use practices for a better optimisation of carbon sequestration.