Abstract
Peatlands are crucial ecosystems in the global carbon cycle because they contain approximately one-third of all organic carbon, equalling more than half of the atmospheric carbon. Moreover, they exert a net cooling effect on the Earth?s climate. Consequently, peatland loss, or degradation?as caused by climate change?may cause the release of vast amounts of stored carbon, enhancing positive carbon cycle-climate feedbacks. In peatland ecology one of the largest uncertainties is how extreme events, such as projected summer droughts, affect the resistance of ecosystem services?including carbon uptake?to, and recovery of these ecosystems after these events. Understanding the underlying mechanisms that play a role in maintaining peatland carbon uptake is crucial for predicting future carbon-climate feedbacks, and requires integrating vegetation, biogeochemical and microbial processes. Experiments on the resistance of grassland ecosystems to environmental perturbations hint towards positive diversity-stability relationships, but more recently the role of diversity has been refuted. I propose to combine field and growth-chamber experiments to study potential mechanisms of diversity controls on the resistance of peatland carbon uptake to, and the recovery of carbon uptake after, extreme drought. I will take an innovative approach by stepping beyond species diversity-ecosystem functioning relationships. Moreover, I will use plant removal experiments to study the effects of plant functional type diversity on peatland processes under climate change. Specifically, I will focus on the effects of summer drought to carbon exchange variables (CO2, CH4, and dissolved organic carbon ?DOC), evapotranspiration, and changes in the composition of the vegetation. Additionally, I will determine the relationships between aboveground (PFTs) and belowground (microbial) diversity (e.g. plant-soil interactions). These insights are necessary to enable accurate projections on the fate of peatland carbon uptake under future climate change.
Netherlands