What is a Wetland?
Wetlands are defined as: An area that is covered with a shallow layer of water, or, at least for some period of time, has waterlogged soils and plant species which grow only in those wet areas.
In simpler terms, a wetland is defined as "wet land". Get it? Of course, this definition can open another can of worms. Many words are used to describe these areas of "wet land". Bogs...marshes...swamps...potholes...sloughs...and the list could go on and on. Several different classification systems are used to distinguish one wetland from another wetland. For this exercise, a system of identifying wetlands by Type as in Type I, III, IV, and V will be used.
As you read the wetland descriptions, keep the following statements in mind:
- All wetland types serve a specific purpose for in the life cycle of waterfowl and other water-dependent wildlife species, such as the muskrat.
- No two wetlands are alike. To group wetlands into one category, would diminish the diversity and complexity of a wetland.
- Some wetlands seem to fall between two different "type" descriptions. For example, during a particularly wet year, a wetland may be classified as a Type IV wetland. However, in past years, it had always been a Type III wetland.
- There can be zones or areas within larger, more complex wetlands that possess Type I, III, IV, and V wetland characteristics. (See Types of Wetlands below.)
Types of Wetlands: A Closer Look
These wetlands usually hold water for a short period of time in the early spring or after a heavy rainfall. They can be called "temporary wetlands" because of the length of time they hold water. Type I wetlands are usually found in low places in cropland or range land. Very little, if any, plant life may be available in cropland areas when water is present. You might think, "Well, it's just a big water puddle!" But, waterfowl and wading birds like the American avocet have a very different opinion.
Role in Waterfowl Production:
Type I wetlands play an important role in the waterfowl production. Upon returning from their winter homes, migrating hens need protein and calcium in their diet for successful egg production . Where do they go? They find Type I wetlands!
The shallow water in a Type I wetland tends to warm up faster than the larger, deeper wetlands (most of those are still frozen). As the water warms, the once-dormant eggs and larvae of small invertebrates become active again. Biologists refer to this high-protein mixture as "soup". Soon the wetland swarms with tasty morsels like snails and insects. This is an excellent source of protein for the hens. "Soup's On!" Come and Get It!
You're in Duck Territory!
The relatively small size and early warm-up of Type I wetlands enables ducks to pair easily and establish a territory during mating and nesting season. For some waterfowl, using Type I wetlands can be a touchy situation. For example, mallards will share the same Type I wetland with other waterfowl species such as pintails and canvasbacks. However, if another pair of mallards should "invade" the same territory, that's when feathers get ruffled.
Type III wetlands hold water longer than Type I. They are called "seasonal wetlands". This wetland type also differs from the Type I wetland in that it generally has more aquatic plants such as reed canary grass, white top grass, arrowleaf, cattails, and bulrushes.
Waterfowl use this type of wetland for feeding and pairing. Hens may build their nests in the vegetation surrounding a Type III wetland. Most ducklings hatch near Type III wetlands. The vegetation provides cover for nesting while the water serves as a feeding area.
This type of wetland is what many people picture as the "classic wetland". Type IV wetlands are usually bigger and hold more water. Unlike the Type I wetland, this wetland will usually hold water year round. The most common above-water vegetation is cattail or bulrush. Vegetation grows in such a way that maze-like pathways to open water are created.
Muskrats inhabit this wetland, as do most waterfowl species and other wetland-dependent birds like the American bittern and black tern. In the case at J. Clark Salyer NWR, this wetland can also provide habitat for gull and tern nesting colonies.
This wetland provides an excellent balance of cover and open water for nesting birds. Once eggs hatch, hens move their broods to these wetlands for protection from predators.
Another common Type IV wetland species is the muskrat. Muskrats use cattails as food and to build their houses, which also provide waterfowl with "loafing areas". No duck wants to be in the water all the time, constantly swimming. So the ducks use the muskrat houses as a place to rest and preen (or clean) themselves. Some ducks even nest on them!
Waterfowl also seek this type of wetland during molting. Molting is the period of time in which birds lose their flight feathers and grow new ones. During this time, a duck is easy prey for predators, therefore, waterfowl seek the safety of open water and vegetation.
Type V wetlands are large areas of open water with vegetation along the shoreline. They may appear to be "small lakes" to many people. This type of wetland holds water all summer and rarely dries up.
Type V wetlands become important for waterfowl in the fall of the year. Adult ducks, as well as the year's fledgling ducks, gather in the open water for the long flight to warmer parts of the country. This event is known as staging. Staging begins as early as late August and continues until the water freezes over. Some ducks such as scaup and mallards are the last to leave the staging areas.
Type I and III wetlands are small, shallow depressions that collect water after rains and during spring snow melt. They are scattered throughout most of North Dakota. Most of these wetlands were formed as glaciers melted some 10,000 years ago. As the ice retreated, "dents" and "dimples" formed on the surface of the land. These depressions collected water from melting glaciers and became wetlands, commonly referred to as "potholes". Today, these Type I and Type III wetlands are known as the Prairie Pothole Region of North Dakota, considered to be the most productive ecosystem on Earth.
Type IV and V wetlands are simply deeper depressions that hold more water. Some of these wetlands may be located within a larger watershed, meaning that more water may run into the wetland, keeping the water quite deep.
Did You Know?
- The Prairie Pothole Region is a 300,000 square-mile ecosystem that supports more than 200 species of migratory birds.
- The Prairie Pothole Region is known as the "duck factory" of North America.
What's It Worth?
- Photographers, educators, birders, wildlife watchers, hunters, and trappers will all agree: Wetlands provide millions of people each year the opportunity to view wildlife at its best: being their "wild-selves" in the comfort of their natural habitat "home". Yet, many people may overlook the other valuable aspects of wetlands.
- Wetlands are important water storage areas, especially for the heavy rains of spring. They act as a natural sponge to hold water. The water is released slowly, helping prevent flooding of streams and river valleys.
- The "sponge" action of wetlands also serves to conserve and retain soil moisture. In some areas, wetlands renew or recharge ground water systems that feed into people's wells.
- Wetlands trap sediment that may erode from upland areas. This prevent silt from clogging up the streams and filling in the lakes. Pothole wetlands trap many chemicals that are carried on the silt, preventing them from polluting rivers, streams, and groundwater. Standing water in wetlands allow sediments to settle and pollutants to be absorbed by plants. This improves our water quality and lowers water treatment costs for home use.
- Farmers use wetlands as grazing areas or hay crops. In drought years, the wetlands may be the only hay available. Also, many Type I wetlands are farmed once the areas dry up.
- Wetlands filter out nutrients that run off upland areas. Wetland plants use up many of these nutrients, keeping them out of streams and rivers where they would over-enrich the waters.
- Wetlands are among the richest habitats on Earth. They provide essential habitats for the breeding, nesting, rearing , and feeding of a wide variety of wildlife species. Wetlands also provide winter cover and predator escape habitats.
- Wetlands provide habitats for more than 200 species of birds.