RIPARIAN ZONE CREATION IN ESTABLISHED CONIFEROUS FORESTS IN IRISH UPLAND PEAT CATCHMENTS:PHYSICAL, CHEMICAL AND BIOLOGICAL IMPLICATIONS

摘要

Plantation forests were established on western Irish peatlands before it became apparent that riparian buffer zones were essential for the health of important salmonid habitats and aquatic ecosystems. The option to retrofit a riparian buffer zone several years before the clearfelling of the main plantation may lessen the possible effect of the clearfelling on receiving waters and provide some protection against sediment and nutrient runoff. The option to create a riparian buffer zone can only be considered if it can be shown that clearfelling this zone of coniferous forestry along the stream does not pose a significant risk to the water bodies in the short term. To assess this risk, the hydrology, water chemistry and biota at three locations in western peatland catchments within mature, harvestable-age forestry plantations were studied before, during and immediately after riparian buffer zones were created. Results indicate that water discharge and suspended sediment increased significantly at two experimental sites post-felling. Maximum and minimum daily temperature and pH also increased significantly at two of the sites. The biological results from macroinvertebrate analysis indicated some significant changes in richness and abundance of species post-felling. The juvenile trout (Salmo trutta L.) densities remained stable over the sampling period and appeared unaffected by the clearfelling operations.