Additional information
About wetlands
A wetland is an area of land whose soil is saturated with moisture either permanently or seasonally. Such areas may also be covered partially or completely by shallow pools of water. Wetlands include swamps, marshes, and bogs, among others. The water found in wetlands can be saltwater, freshwater, or brackish..
Wetlands are considered the most biologically diverse of all ecosystems. Plant life found in wetlands includes mangrove, water lilies, cattails, sedges, tamarack, black spruce, cypress, gum, and many others. Animal life includes many different amphibians, reptiles, birds, insects, and mammals.
In many countries wetlands are the subject of conservation efforts.
Conservation efforts
Wetlands have historically been the victim of large-scale draining efforts for real estate development, or flooding for use as recreational lakes. By 1993 half the world's wetlands had been drained. Since the 1970s, more focus has been put on preserving wetlands for their natural function — sometimes also at great expense. Wetlands provide a valuable flood control function. Wetlands are very effective at filtering and cleaning water pollution, (often from agricultural runoff from the farms that replaced the wetlands in the first place). To replace these wetland ecosystem services enormous amounts of money have been spent on water purification plants and remediation measures, constructing dams, levees and other artificial flood controls.
List of wetland types
- Swamp
- Freshwater swamp forest
- Coniferous swamp
- Marsh
- Salt marsh
- Bog
- Peat swamp forest
- Slough
- Flooded grasslands and savannas
- Constructed wetland
- Riparian zone
- Fen
- Vernal Pool
Wetland functions
The main functions performed by wetlands are water filtration, water storage, biological productivity, and provide habitat for wildlife.[4]
Filtration
Wetlands support a vast and intricate food web which provides many functions and services to nature and humans.
Wetlands aid in water filtration by removing excess nutrients, slowing the water allowing particulates to settle out of the water which can then be absorbed into plant roots. Studies have shown that up to 92% of phosphorus and 95% of nitrogen can be removed from passing water through a wetland. Wetlands also let pollutants settle and stick to soil particles, up to 70% of sediments in runoff. Some wetland plants have even been found with accumulations of heavy metals more than 100,000 times that of the surrounding waters' concentration. Without these functions, the waterways would continually increase their nutrient and pollutant load, leading to an isolated deposit of high concentrations further down the line. An example of such a situation is the Mississippi River’s dead zone, an area where nutrient excess has led to large amounts of surface algae, which use up the oxygen and create hypoxic conditions (very low levels of oxygen).
Wetlands can even filter out and absorb harmful bacteria from the water. Their complex food chain hosts various microbes and bacteria, which invertebrates feed on. These invertebrates can filter up to 90% of bacteria out of the water this way.
Storage
Wetlands can store approximately 1-1.5 million gallons of floodwater per acre. When you combine that with the approximate total acres of wetlands in the United States (107.7 million acres), you get an approximate total of 107.7 - 161.6 million million gallons of floodwater US wetlands can store. By storing and slowing water, wetlands allow groundwater to be recharged. "A 550,000 acre swamp in Florida has been valued at $25 million per year for its role in storing water and recharging the aquifer." And combining the ability of wetlands to store and slow down water with their ability to filter out sediments, wetlands serve as strong erosion buffers.
Biological Productivity
Through wetlands ability to absorb nutrients, they are able to be highly biologically productive (able to produce biomass quickly). Freshwater wetlands are even comparable to tropical rainforests in plant productivity. Their ability to efficiently create biomass may become important to the development of alternative energy sources.
While wetlands only cover around 5% of the Conterminous United States’s land surface, they support 31% of the plant species. They also support, through feeding and nesting, up to ½ of the native North American bird species. Bird populations, while playing a major role in food webs, are also the focus of several, well-funded recreation sports. (Waterfowl hunting and bird watching to name a pair).
Wildlife Habitat
Wildlife habitat is important not only for the conservation of species but also for a number of recreational opportunities. As a conservation purpose, wildlife habitat is managed for maintaining and using the resources in sustainable manner. Ninety-five percent of all commercially harvested fish and shellfish in the United States are wetland dependent. Muscatatuck National Wildlife Refuge is an example of recreational destination for hunting, fishing, wildlife observation and photography that has a good wildlife management. Some parts of the area are wetlands managed for providing habitat of migratory birds, such as waterfowl and songbirds. The 14 million United States hunters generate in excess of $50 billion annually in economic activity. This does not include the 60 million people that watch migratory birds as a hobby. The Florida Keys wetland area generates more than 800 million dollars in annual tourism income alone.
