| The effects of exposure to agricultural effluent on amphibians were investigated with red legged frogs (Rana aurora aurora) in the Elk Creek Watershed, British Columbia, Canada. In 1999, an egg and tadpole in situ site exposure design was created along a gradient of agricultural activity (upper Elk Creek to lower Elk Creek) to determine if effects related to water quality. Significant effects on R. aurora aurora survivorship and biochemical stress indicators (plasma glucose, plasma lactate, haematocrit, and leucocrit) were observed at downstream sites adjacent to agricultural activity, but were confounded by site water temperature. An unexplained mortality event and inhibited metamorphosis, most likely as a result of cool-late season temperatures, were also observed. Similar results were observed in Threespine stickleback (Gasterosteus aculeatus) exposed in mesocosms along Elk Creek. (Abstract shortened by UMI.). |
