What Are Freshwater Wetlands?

The term "wetlands" encompasses a wide variety of aquatic habitats including swamps, marshes, bogs, prairie potholes, flood plains, and fen. 

Natural wetlands are lands which, due to geological or ecological factors, have a natural supply of water—either from tidal flows, flooding rivers, connections with groundwater, or because they are perched above aquifers or potholes. Wetlands are covered or soaked for at least a part, and often all, of the year. This makes wetlands intermediaries between terrestrial and aquatic ecosystems. They are neither one or the other, and yet they are both. 

What is a marsh?
A freshwater marsh is an inland area inundated with 1–6 feet (33–200 cm) of water, containing a variety of perennials (mostly grasses), forbs (flowers), and bushes, rather than trees, as in swamps. 

Marshes have an interesting mix of plant and animal life, one that effectively demonstrates the interconnectedness of living things. They are home to yellow-headed and red-winged blackbirds, herons, egrets, rails, bitterns, moorhens, ducks and geese. Most migratory species, in fact, rely on a network of wetlands to get from their southern habitats to nest sites further north. 

Muskrats are central to many marshes, keeping aggressive plants in check and crafting bird protection by carving out habitat. Minks and otters frequent wetlands. Raccoons, opossums, even moose can be found foraging around marshes, particularly when water levels drop. Marshes also host frogs, turtles, and snakes, salamanders, and an immense variety of insects, including aquatic, flying, and grazing insects. 

What is a swamp?
Swamps are slow moving streams, rivers or isolated depressions that host trees and some shrubs. 

What is a bog?
A bog is a peat-accumulating wetland. Some shrubs and evergreens grow in bogs, as do mosses. Most water comes from precipitation. There is usually no direct inflow or outflow of water.

What is a prairie pothole?
A prairie pothole is a wetland area found in the northern Great Plains. These shallow or bowl-like depressions have variable wetness. They are often used for breeding by birds. Prairie potholes are not wet year-round.

What is a riparian marsh?
Marshes that occur along rivers are called riparian marshes. These marshes serve two ecological roles: to absorb excess water when river levels are high and to release water when river levels are low. These balancing forces help prevent floods and droughts. 

However, for the past 100 years mankind has straightened and deepened rivers in order to make them more accessible for commerce. The unfortunate side effect is the loss of riparian marshes. Today, very few riparian marshes are left. Some scientists believe that the great Mississippi River flood of 1993 was worsened, in part, by the loss of these wetlands. 

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