Wetlands in Region 8In the semi arid climate of Region 8, where water can be scarce, terrestrial ecosystems tend to have limited productivity and support communities adapted to low-water conditions. In contrast, wetlands provide plant and animal communities with water-rich environments and, as such, wetlands are some of the most highly productive systems in the region. The many types of wetlands in Region 8 are all unique in their hydrology, plant communities and soils and are very important components to the functioning of ecosystems throughout the region.
On this page
- Classification of Wetlands
- Regional Wetlands and Related Habitats
- Wetland Preserves in Region 8
- Benefits of Wetlands in Region 8
- Threats to Regional Wetlands
Classification of Wetlands and Deepwater Habitats of the United States. The Cowardin system is used by the U.S. Fish and Wildlife Service for the National Wetlands Inventory. In this system, wetlands are classified by landscape position, vegetation cover and hydrologic regime. The Cowardin system includes five major wetland types: marine, tidal, lacustrine, palustrine and riverine.
Another common wetland classification system, used by the Army Corps of Engineers, was developed by Brinson and is described in A Hydrogeomorphic Classification for Wetlands. As the title implies, wetlands are classified by their geomorphic setting, dominant water source (e.g. precipitation, groundwater or surface water) and hydrodynamics. The hydrogeomorphic (HGM) includes five major wetland types: riverine, slope depressional, flat and fringe.
- Wet meadows
- Prairie potholes
- Seeps and springs
- Riparian wetlands
- Fringe wetlands
- Mudflats and salt flats
Wet meadows are widely distributed throughout North America and are some of the most common types of wetlands. These systems are often dominated by grasses and herbs, including cattails and rushes. Wet meadows are without standing water for most of the year, but the soils remain saturated because of high water tables fed by both surface and groundwater sources.
Prairie potholes are freshwater marshes that exist in isolated depressions. When the glaciers retreated about 12,000 years ago, they left portions of the Upper Midwest, U.S. covered with depressions, creating the prairie pothole region. Although they comprise only about 10 percent of the nation's inland wetlands, these small depressions, ponds and lakes provide habitats for over half of the waterfowl in North America. Prairie wetlands range in size from less than one acre to hundreds of acres. The pothole region is part of the most productive breeding habitat in North America for waterfowl and shorebirds.
Playas, named after the Spanish word for "beach," are ephemeral wetlands found in arid and semi-arid climates across the Southern High Plains of North America. These depressional wetlands tend to be dry for most of the year and fill after spring rainstorms, although there are some playas that are formed from groundwater sources where the water table is high enough to saturate the soils. Playas provide an important habitat for migratory birds and waterfowl and are an important source of water for recharging the Ogallala Aquifer.
Fens are wetlands with extremely high plant biodiversity, although plant communities are often dominated by sedges and willows. These wetlands have a constant flow of groundwater that saturates the soils and maintains anoxic conditions, leading to slow organic matter decomposition and the formation of a peat layer.
Seep and spring wetland areas are formed when fractures or fault zones allow water from deeper aquifers to discharge at the surface. The presence of seeps and springs is largely dependent upon characteristics of the local and regional geology. Because of the water source, seeps and springs provide relatively constant inflow and water temperature and can support unique species adapted to these conditions.
Headwater wetlands are located in the uppermost portions of watersheds, upstream of perennial streams. Like seeps and springs, these systems often support unique species not found in wetlands lower in the watershed. Precipitation, overland runoff and groundwater are the primary sources of water in these systems.
Riparian wetlands are located along rivers and streams, where soils and soil moisture are influenced by the adjacent river or stream. They typically contain plants such as cottonwoods, willows, and shrubs and are natural corridors used by a variety of wildlife for food and shelter. Riparian areas along streams make up less 3 than percent of the Colorado landscape, but contain about 75 percent of Colorado's plant and animal diversity. Wetlands associated with riparian corridors help control floods and assist in keeping streams and rivers clear by reducing sediment loads.
Fringe wetlands are found on the shores of lake and pond ecosystems where the water table of the pond or lake is high enough to support vegetation associated with saturated soils. These areas can act as a buffer for pollutants and sediments from upland runoff and can also prevent erosion from runoff or wave activity. These systems provide transitional habitat between the aquatic and upland environments, and inundated areas can provide refuge for juvenile fish and aquatic invertebrates.
Mudflats and salt flats
Mudflats and salt flats are unvegetated areas of fine-grained sediment (mud) that are sometimes flooded. In Region 8, these systems can be found in freshwater lake and river systems, with the salt flats located predominantly in the Great Salt Lake ecosystem. These areas can be extremely productive areas for invertebrates.
Wetland ecosystems offer a tremendous opportunity for educational experiences, providing students with an outdoor classroom to learn about organisms and the ecosystem they live in. The same aspects of nature that provide educational opportunities also make wetlands a destination for recreational activities like hunting, fishing, swimming, birding, boating and hiking.
Last, but not least, wetlands are well known for providing vital habitat for many species of plants, waterfowl, fishes, mammals, amphibians and songbirds. In Region 8, marsh systems, including wet meadows, prairie potholes and playas, are the most important habitat for waterfowl; and amphibians rely on these marsh systems almost exclusively. Wet meadow systems also provide important foraging opportunities for domestic livestock and many other mammal species. Many fishes, including native trout species, rely on headwater, riparian and fringe wetlands for bank habitats and cover from predators.
Other less obvious threats are the impacts to wetlands and riparian areas by the introduction of exotic plants such as Canada thistle, leafy spurge, purple loosestrife, salt cedar and Russian olive. These plants choke out the native wetland vegetation in a very short period of time, destroying the native wetland outright or reducing the functions considerably. If left unchecked, purple loosestife will eventually become a monoculture of loosestrife and poses a severe threat to a waterfowl habitat.
Salt Cedar, and Russian olive are two exotics that have been responsible for the loss of riparian habitats in the west. Wildlife biologists now recognize that Russian olives are of little or no use to many wildlife species. Salt cedar has little to offer to wildlife and is rapidly replacing native trees such as cottonwoods along the Rio Grande and the Colorado river.