Wetlands are the interface between dry or terrestrial habitats and aquatic environments including streams, lakes and seas. Around the Great Lakes they take four basic forms. Swamps are a cross between forest and aquatic ecosystems, inhabited by woody species: conifers, hardwoods or shrubs. Bogs are characterized by acidic, peaty soils with little water movement and feature flora such as blueberries, orchids and carnivorous plants. Fens are similar to bogs, but with more water movement their soils are less acidic. The dominant plants are sedges and low shrubs.
The Point Pelee wetland falls in the fourth category, marshes, which are normally associated with ponds, lakes and rivers. Typical plants may include reeds and rushes, but here the marsh takes the form of a cattail mat thick enough to support the movement of wildlife such as muskrat, mink and even deer. In patches the water is more open, but the surface may be covered with pond weeds like water-lilies.
Wetlands are important because they act as natural sponges, absorbing water so it moves more slowly through the system. This prevents flooding and shoreline erosion. In the 19th Century people thought that anything obstructing rivers would increase flooding, so they frequently removed islands and wetlands to let water move more readily through urban areas. Such practices actually increased the problem.
More recently some cities have begun to let wetlands regenerate. Wetland construction is commonly a part of housing developments, though often at the expense of more complex pre-existing natural habitats.
Wetlands are also well-designed to filter out pollution, particularly nitrogen and phosphorous. They are also useful for removing heavy metals. Industries are experimenting with constructing wetlands for this purpose.
Meanwhile wetlands exceed other temperate habitats in that they produce as much oxygen, per area, as tropical rainforest.
Besides, wetlands provide a natural nursery for many species of native plants and wildlife. More than 40 species of birds nest in Point Pelee's marsh and 66 species of dragonflies and damselflies breed there. These habitats also provide a major food source for humans and animals. They also offer recreation in the form of canoeing, birdwatching and fishing.
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