Assessing the role of feedbacks and uncertainty in peatland hydrology: A modelling framework

English Abstract:

Northern peatlands provide important global and regional ecosystem services (carbon storage, water storage, and biodiversity). However, these ecosystems are facing large increases in the severity, areal extent, and frequency of climate-mediated (e.g., wildfire, drought) and land-use change (e.g., drainage, flooding, and mining) disturbances that are placing the future security of these critical ecosystem services in doubt. Here we present a modelling framework for testing the importance of various hydrological feedbacks, and the associated parameter uncertainty, that regulate the response of water table depth to a range of both seasonal water deficits and disturbances in northern peatlands. The modelling framework explicitly accounts for the relative strength of these feedbacks for different peatland types within different climate regions. From our analyses, we present a subset of feedbacks that operate at short (sub-annual) timescales. Specifically, we implement a partial factorial design for these feedbacks in order to examine the interaction between water table depth and each of peat deformation, specific yield, and surface resistance to evaporation. Our findings suggest that the relative strength of these feedbacks, within the context of peatland type and regional climate, are important for quantifying the impact of climate change and disturbances on peatland water storage. As such, we argue that in order to further develop our understanding of peatland response to disturbance, a more integrative ecohydrological model that couples key hydrological, biogeochemical, and ecological processes within a feedbacks framework is needed.