CORNWALL, Ontario – While the summer’s heavy rainfall may have proven helpful to the area’s fish population, it may have put quite a damper on the conditions of other wildlife.
“Flooding would be expected to have strong impacts on species that are not able to adjust quickly to higher water levels,” said Jeff Ridal, Executive Director and Chief Research Scientist at the River Institute. “Wildlife that depend on borders of the river for reproduction (e.g. waterfowl, turtles) may experience some difficulties due to loss of terrestrial habitat, or nests being positioned in unfavourable locations when water levels recede.”
Ridal says that another trend this year is the dwindling numbers of juvenile eels migrating upstream past the Moses-Saunders Dam.
“One theory to account for these low numbers is that the water levels and increased flow of the river is somehow acting against their upstream migration pattern,” said Ridal. “But this is just a theory at this point.”
Ridal says the overall effect of heavy rainfall is an increase in the river’s productivity. Translation: there is a silver lining to rainfall of biblical proportions.
“Usually the bottom line is that water is good for fish,” said Ridal. “We’re seeing much wider diversity of species than in previous years.”
Due to flooding of terrestrial areas, more aquatic habitat is being created, infused with additional nutrients. Ridal says that flooding not only provides more nutrients at the base of the food chain, but allows further access to more habitat, and higher reproductive success for most species.
“Species like waterfowl, birds of prey, and other species that feed on fish should also benefit from this increased food supply,” said Ridal. “The higher water levels and nutrient runoff have created very good growing conditions for submerged aquatic vegetation in some areas, which in turn has created more habitat and food for aquatic species.”
