Impact of Local Human Activities on Dissolved Organic Carbon Export from Peatlands-a Global Review
Résumé
We performed an extensive literature review and gathered worldwide annual DOC exports from peatlands, tracking the influence of human disturbances. The sites were binary classified based on mentioned human activities in their watersheds. Global variability of DOC exports was investigated using hydro-meteorological data and topographic characteristics of peatlands as explanatory variables. This investigation shows that DOC exports from peatlands increase from high to low latitudes and that peatlands impacted by human activities export significantly more DOC (33.3 g C m-².yr-1 in average) than non-impacted ones (25.0 g C m-².yr-1 in average). Multiple linear regression models reveal contrasted controls and responses to environmental changes of DOC exports between non impacted and impacted sites. Temperature is the main significant predictor explaining DOC export variability for non-impacted peatlands whereas it is specific discharge for impacted sites. Partial linear models reveal that for a given temperature rise, non-impacted peatland would export more DOC than impacted ones. An inverse behaviour is observed for a given discharge rise. This study reveals that so far, DOC export studies do not cover all worldwide peatlands areas. Given their importance for carbon balance assessments and their sensitivity to anthropogenic disturbance, DOC exports from peatlands should be more systematically assessed.