Modelling root dynamics in arctic tundra ecosystems and quantifying vegetation feedback to regional and global climate change

Root dynamics has emerged as a critical process in the Arctic tundra ecosystems, as roots constitute a larger part of plant biomass and are a key player in regulating water, nutrient and carbon fluxes.

However, due to the scarcity of data, Arctic tundra root growth in response to changes in environmental conditions associated with warming is still poorly understood. Important traits and function of roots are largely lacking in current terrestrial biosphere models.

This project aims to develop a dynamic root scheme in a dynamic vegetation model (LPJ-GUESS) to properly represent root dynamics in terms of carbon allocation, dynamic root distribution and plastic responses of taking up nutrients and water. Two recent databases, (i.e.

Fine-Root Ecology Database version 2 and Northern Permafrost Soil Database) will be integrated into the model to parametrize root traits and soil conditions.

Four years of manipulation experiments for dry and wet tundra ecosystems in West Greenland will be used to calibrate the model to simulate root dynamics.

The model will further be incorporated in the framework of a regional and global Earth system model to assess the impacts of biogeophysical and biogeochemical feedback on the regional and global climate system.

The outcomes of this project will improve our understanding of responses of belowground vegetation to climatic warming and permafrost thawing and their impacts on greenhouse gas emissions and nutrient cycling.