1The aim of this study was to investigate the release of phosphorus (P) to receiving waters resulting 2 from harvesting 34-year-old lodgepole pine trees in an upland peat catchment. The study site was 3 within a 25.3-hectare (ha) area, and was drained by a stream that received flows from ploughed 4 furrows, mainly, via collector drains, and discharged directly to the salmonid Shrahrevagh River,

The acid-sensitive upland blanket peat catchments are important habitats for diatom assemblages.In this study, the distribution patterns of epilithic diatom assemblages in the streams of upland forested blanket peat in north-west of Ireland are presented and the associated environmental factors are discussed. A total of 43 sites in 16 rivers were sampled. Multivariate analysis highlighted alkalinity and conductivity as the main physicochemical drivers of riverine diatom assemblages. Contrary to expectations nutrients were not found to have a major influence on the diatoms. A major flood event had a significant impact on the diatom assemblage, and one year after the event, long stalked diatom taxa were still largely absent from the river, indicating that floods could be one of the important factors affecting diatom assemblages. However, the ecological status of the affected sites, as determined by the EQR, did not alter from before to after the flood. The results of this study could be applied to similar acid-sensitive upland peat forest catchments and used as the benchmark to assess the impact of forest operations and peat degradation on ecological status.

No abstract

organic) and returned to pre-clearfelling levels, or below, within 6 months of the 33 commencement of clearfelling. Exports of TP and DRP from the study site were 0.9 and 0.4 34 2 kg ha -1 yr -1 , which were greater than the study control (0.6 and 0.2 kg ha -1 yr -1 , respectively). 35This indicated that the mitigation practices employed on site were not effective in phosphorus 36 retention. 37 38

11Forest harvesting activities, if not carefully carried out, can disturb the forest soils and 12 can cause significant suspended solid concentration increases in receiving waters.