LAUSR

Abstract We restored small downstream sections of forestry-drained peatland catchments for use as wetland buffer areas and studied the effects of their restoration on the exports of nitrogen, phosphorus, dissolved organic carbon, and dissolved aluminium and iron. Even though the buffer areas were small relative to their catchment areas (0.5–3.5%), buffer restoration clearly increased pollutant exports. Thus, even though restored buffer areas proved later to be efficient in retaining pollutants from their upstream catchment area, turning from an initial restoration-induced pollutant source to their net sink may take a long time. In one restored buffer, the whole concept of restoration to improve water quality was judged questionable due to significantly deteriorated water quality. We presented a hypothesis that high iron content in peat may be a common denominator for the sites with high carbon and organic nutrient exports after restoration of forestry-drained peatlands. We conclude that it may not always be reasonable to restore drained peatlands for use as wetland buffers due to high initial pollution exports.