How does climate warming duration affect above- and belowground plant traits and overall tundra ecosystem functionality?

ended

Climate warming is changing vegetation across the Arctic tundra region. Warmer temperatures enhance plant photosynthetic uptake of atmospheric CO2 but warming also promotes microbial decomposition of the vast permafrost carbon pool, releasing greenhouse gases to the atmosphere in a positive feedback-loop. In addition to temperature, changes in plant composition also strongly affect carbon and nutrient cycling rates through species-specific differences in leaf and root characteristics. These so-called plant functional traits provide an essential link between vegetation change and ecosystem functionality, and understanding how climate warming affects tundra plant traits is therefore vital for accurately forecasting ecosystem impacts over the coming century. Climate-change manipulation experiments allow for process-based investigations into how ecosystems respond mechanistically to warming. However, lack of long-term experimental warming studies in the Arctic currently impedes our ability to predict future climate responses accurately over decadal time-scales because extrapolation of short-term data consistently leads to faulty long-term predictions. In WarmTraits, I will utilize a unique opportunity to destructively sample in a long-term experiment where greenhouses have warmed tundra plots for one, 11, and 21 years, respectively. Thereby, I will quantify the mechanistic effects of increasing climate-warming duration on a very comprehensive suite of above- and belowground plant functional traits. In addition, I will directly link functional trait changes to ecosystem functionality by measuring important ecosystem carbon and nitrogen cycling processes using stable isotope labelling. I have the required expertise in ecosystem ecology and biogeochemistry to implement the project objectives successfully, and my host’s expert knowledge ensures that I will receive top-tier research training in plant physiology and stable isotope techniques.