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Driving-C

Do dryland ecosystems control variability and recent trends of the land carbon dioxide sink?

Funder: UK Natural Environment Research Council

Working with: Prof Richard Brazier, Prof Stephen Sitch, Dr Tim Hill (all @ Exeter).

Plus: international collaborators across flux tower sites in the US South-West.

Postdoctoral fellow: Dr Andy Cunliffe

Research technician: Fabio Boschetti

Summary: Drylands cover ca. 40% of the global land area and are predicted to cover 50% by 2100, storing 8 - 25% of terrestrial organic Carbon (C). Dryland climates are highly variable, particularly in terms of rainfall and, as water-limited ecosystems, C uptake and release is very sensitive to this variability. Recent large-scale modelling studies suggest that temporal fluctuations in dryland vegetation biomass may control both inter-annual variability (IAV) and long term trends in the land C sink. If such predictions are correct, drylands may become increasingly important drivers of global C cycles and tropical rainforests may become less relevant in the future. Yet such predictions are empirically unfounded, indeed a strong divergence in opinion exists on the potential for C storage in drylands. This project uses existing global datasets from all major dryland regions and new measurements of biomass stocks and net ecosystem exchange (NEE) of C from the most intensively monitored dryland region (the US southwest), to evaluate and improve both empirical understanding and models of vegetation dynamics which will establish unequivocally the role of dryland ecosystems in global C cycles.

 

My role in this project is the collection and analysis of new proximal sensing data (drone-derived structural estimates of dryland plants) which will be the first to demonstrate inter-annual variability in above-ground biomass within these systems. Alongside we will also be using varied satellite data products to evaluate the temporal and spatial dynamics of dryland ecosystem productivity. Such data will inform evaluation of current models that represent the role played by such systems in the global carbon cycle.

Driving-C colleagues during recent fieldwork in Arizona

Conducting drone flights over dryland ecosystems

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