Getting to the root of the matter: variations in vascular root biomass and production in peatlands and responses to global change

Root biomass, production and decomposition have been poorly studied in peatland ecosystems despite evidence that they may be equal to or greater than aboveground vascular plant components and contribute significantly more carbon (C) to the soil organic matter pool. At the same time, global change phenomena such as water table drawdown (via rising temperatures) and increased nitrogen deposition threaten to dramatically alter these systems, primarily through changes to vegetation. This makes quantifying root biomass, production, and decomposition critical to our understanding of peatland C cycles. Understanding how these belowground stocks and fluxes vary with aboveground plant components in relation to environmental (climate, water table) and biological (vegetation type, species diversity) factors can provide insight into how peatland plant communities adapt to different environments. Additionally, the implications of these adaptations to C cycling within and among sites and in response to global change phenomena can then be considered. My research began by evaluating relationships between above- and belowground biomass and production in a review of wetland plant communities and determining the effect of vegetation type and environmental and climate factors on these relationships within and among wetland types, including peatlands. My subsequent research focused specifically on bog plant communities in Canada and Finland, and the relationships between belowground biomass and production and aboveground biomass as they relate to variations in water table, a key environmental driver within a bog site. Root decomposition rates, a crucial process determining root contributions to soil organic matter, were also studied for the two main evergreen and deciduous shrub species as they relate to root size and soil depth using the litterbag method. The final component of my research evaluated the response of root pro