| Summary: | The relationships between local and catchment-wide land use patterns and the spatial distribution of stream habitat variables within the Grande Cascapedia drainage basin were investigated using a geographic information system (GIS). Stream habitat variables including substrate composition and channel morphology were sampled at 48 study sites, ranging from highly disturbed to relatively pristine forest conditions in 2nd to 5th order tributaries. Land use and geology-structure variables were extracted for each catchment at four spatial scales using a GIS. The transition between pool-riffle and boulder-rapid morphologies occurred between channel gradients of 1.5% and 1.7%. The surface grainsize distribution is affected by the hydraulic power of the reach, while the subsurface grainsize distribution is associated with the degree of valley incision. The amount of logging within a 1 km radius of a sample site increases the occurrence of fine sediment within the substrate. There was, however, a surprising lack of relationship between the majority of road density metrics and the level of fines within the substrate.
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