If beaver dams and woody debris slowed the flow of upland rivers, existing flood protection systems would be quite adequate.
Small upland rivers are often nearly completely blocked by landslide material, thereby reducing their potential to transport sediment.
During the courtship ritual a spawning site is selected and cleaned — hard surfaces such as rocks in upland rivers and impoundments, and logs and occasionally clay banks in lowland rivers, at a depth of 2 3 metres (6 10 ft), are selected.
Within this network of upland rivers, watershed position was accompanied by a strong cline in genetic diversity.
Escaped farmed salmon have also been documented in Southern Upland Rivers but monitoring of these rivers has been limited (M.J. Morris, D.J. Fraser and J.A. Hutchings, unpublished data).
Marked differences in pH between Southern Upland Rivers and the ancestral source river of regional farmed salmon provided a benchmark for evaluating the risk posed to small and declining fish populations from interbreeding with their escaped farmed counterparts.
Nonetheless, these latter interactions are unlikely to have affected our results because Southern Upland Rivers have high levels of dissolved organic matter which decrease the toxicity of heavy metals (Farmer et al. 1980; Lacroix 1985).
However, there are few broad scale techniques for quantifying the sources of sediment, i.e. upland vs. river bank erosion.
Within the City of Edmonton, Canada, we surveyed 75 urban wetlands (stormwater, natural upland and river valley) using call surveys and trapping for amphibian species.
