Consequences of global biodiversity loss and climate change for decomposer communities and implications for forest carbon fluxes

Forests play a central role for global carbon cycling and biodiversity. Yet, the unabated continuation of climate change and increasing anthropogenic pressure on forest resources are altering forest ecosystems by modifying species composition and ecosystem processes. Increasing temperatures are likely to increase decomposition rates and thus carbon emissions, while the opposite effect may be expected from loss of decomposer biodiversity as land-use intensity increases. However, it remains unknown how climate change and land use interactively shape decomposer communities, decomposition rates and carbon fluxes. This limits the ability to model the future of the global forest carbon sink as well as of forest policy and management to counteract undesired developments. Here, I will investigate the joint effects of climate change and land use on decomposer communities and carbon fluxes from wood decomposition at the global scale, as well as the underlying processes and mechanisms. Making use of an operating network of 60 research sites on six continents, I will study how biodiversity-decomposition relationships and effects of land use change along global climate gradients. Empirical results will be used to model carbon fluxes from wood decomposition at the global scale and to generate projections of carbon fluxes under different scenarios of forest use and climate change. Extensive experiments will be conducted both in the field and in walk-in climate chambers to identify which facet of biodiversity drives wood decomposition and to unravel the mechanisms behind the climate-dependency of biodiversity-decomposition relationships. The BIOCOMP project will bring about a new level of understanding of how biodiversity and carbon cycling in forest ecosystems worldwide will change as a result of climate change and land use, and it will provide the data and strategies to tackle one of the most pressing challenges of current climate and forest policy.