A wetland is a place where the land is covered by water, either salty, fresh or alkaline water. These places are physically seen as swamps, ponds, marshes, deltas, edges of lakes or places that frequently experience flooding.
Wetlands are very productive ecosystems hosting a variety of species from microbes, insects, plants, amphibians, reptiles, birds, fish and mammals.
Benefits of Wetlands
Wetlands protect water quality by trapping sediments and retaining excess nutrients and other pollutants such as heavy metals, pesticides and fertilizers.
These is especially important when a wetland is connected to groundwater or surface water sources (such as rivers and lakes) that are in turn used by humans for drinking, swimming, fishing, or other human activities and for wildlife that inhabit this areas.
Wetlands protect surface waters from the problems of nutrient overload by removing the excess nutrients, some of which are taken up and used by wetland plants, and some of which are converted to less harmful chemical forms in the soil. Therefore acting as carbon sinks.
Toxic chemicals reach surface waters in the same way as nutrients, and can cause disease, death, or other problems upon exposure to plants and animals (including humans).
Wetlands hold the excess runoff after a storm, and then release it slowly. The size, shape, location, and soil type of a wetland determine its capacity to reduce local and downstream flooding.
While wetlands cannot prevent flooding, they do lower flood peaks by temporarily holding water and by slowing the water’s velocity.
Wetland soil acts as a sponge, holding much more water than other soil types. Even isolated wetlands can reduce local flooding — if the wetlands were not there to hold storm water runoff, backyards and basements might end up under water.
Wetlands that occur along the shoreline of lakes or along the banks of rivers and streams help protect the shoreline soils from the erosive forces of waves and currents.
The wetland plants act as a buffer zone by dispelling the water’s energy and providing stability by binding the soils with their extensive root systems.
Aquifers and groundwater are replenished with water by precipitation that seeps into the ground and by surface waters.
Those wetlands connected to groundwater systems or aquifers are important areas for groundwater exchange. They retain water and so provide time for infiltration to occur.
Groundwater, in turn, provides water for drinking, irrigation, and maintenance of stream flow and lake and reservoir levels.
During periods of low stream flow (or low lake water levels), the slow discharge of groundwater often helps maintain minimum water levels. In addition, wetlands located along streams, lakes, and reservoirs may release stored water directly into these systems, thus also contributing to their maintenance.
Wetlands’ many intricate connections with groundwater, stream flow, and lake and reservoir water levels make them essential in the proper functioning of the hydrologic cycle.
Many species of birds, fish, mammals, reptiles, and amphibians rely on wetland habitat for breeding, foraging, and cover.
The special wetland conditions provide unique habitat for species that cannot survive elsewhere. Migratory birds depend on wetlands, and many endangered and threatened animal species require wetlands during part of their life cycle. The incredibly high rate of wetlands loss has contributed to their reduced numbers.
Wetland plants and small animals (insects) are essential links at the lowest levels of the food chain. A wetlands environment supports these plants and animals, which in turn support the larger animals that feed on them. If we diminish the lowest levels of the food chain, the higher levels will suffer as well.
Wetlands provide natural flood control and water treatment systems.
The costs of replacing the functions provided by wetlands could far outweigh the land purchase price of preserving the natural wetland systems.
Nature photography, bird watching and overall aesthetic value.
Current trends on wetlands
Wetlands are being partially filled if not damaged.
Degraded wetlands can lose their capacity to remove excess sediments, nutrients, and other pollutants, and lose its habitat value for wildlife.
When we destroy wetlands, we release carbon dioxide (a greenhouse gas) into the atmosphere since wetlands act as carbon sinks.
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More information on Wetlands here.