Wetlands offer many environmental benefits, by providing habitat for wildlife improving water quality by serving as biological filters and mechanical settling and filtering ponds, which help to remove impurities from the water recharging groundwater augmenting low flow in watercourses buffering against drought reducing the risk and damage of flooding by storing large volumes of water during heavy rainfall, rapid thaws, or runoff events stabilizing shorelines. Canadian wetlands are especially noted for supporting North America's waterfowl species. However, other avian groups, including songbirds, shorebirds, and raptors, use wetlands for nesting habitat, protective cover, or sources of food.
Wetlands are equally important to non-avian wildlife.
This considerable biodiversity is common within wetlands because of the unique meshing of water and land. These transition zones are highly productive, because they provide breeding and feeding grounds for thousands of invertebrate species at the base of food chains. Directly or indirectly, these invertebrates contribute to the critical habitat that supports 23 species of birds, mammals, amphibians, and reptiles, as well as numerous other fish and plant species, currently deemed endangered or threatened in Canada. By adding to the habitat diversity of the landscape and accommodating species that use multiple habitats, wetlands also contribute significantly to the biological diversity beyond their borders. For example, deer or moose commonly use a hardwood forest in winter when thick conifers, commonly associated with swamps, are nearby to provide thermal cover.