Groups as diverse as government agencies and conservation organizations are concluding one thing these days....that wetlands are valuable ecosystems.
Fish and Wildlife
Wetlands are important to fish and wildlife populations and that roughly 96 percent of commercially important species of fish are wetlands-dependent. A 1989 study by the American Fisheries Society's Endangered Species Committee found nearly one third of native North American freshwater fish species are endangered, threatened or of special concern. Of that number, 93 percent were adversely affected by habitat loss.
In addition, one tenth of North America's freshwater mussels (such as clams) have become extinct. About three quarters of the remaining are classified as rare or imperiled. This is primarily due to habitat destruction from dam construction and pollution.
Also, about 80 percent of America's bird population relies on wetlands, according to the U.S. Fish and Wildlife Service. A prime example is the wood stork, whose population has dropped from 60,000 birds in the 1930's to around 10,000 by 1984. All of this decline is attributed to the loss and degradation of wetlands, according to the U.S. Environmental Protection Agency's Office of Wetlands, Oceans and Watersheds.
Some species of frogs, toads and salamanders depend exclusively on seasonal wetland areas as their only habitat. Seasonal wetlands are those areas that have standing water for relatively brief periods. They are temporary and often isolated, making them safe from predatory fish and other creatures, allowing the amphibians to thrive.
Wetlands also are invaluable for a variety of water quality functions they naturally perform. These include, but are not limited, to the following:
- Denitrification: Some studies show that in certain instances, wetlands can remove from 70 to 90 percent of nitrates. One study in the southeastern U.S. projected a 20-fold increase in nitrogen loadings to streams as a result of a total conversion to adjacent bottomland hardwood forested wetlands to cropland.
- Trapping sediments which can keep large amounts of phosphorous from entering adjacent rivers, as well as preventing erosion and sedimentation.
- Flood control: Wetlands can help buffer storm surges. A recent study by the U.S. Army Corps of Engineers indicates. Studies in the midwest show flood water flows can be reduced by 80 percent in watersheds with wetlands, as opposed to those without them.
- Groundwater Recharge: Returning water to underground aquifers is known as "groundwater recharge." Much of the water in a wetland used for recharge would have been deposited there during wet periods, so the wetland would not only stem flooding by retaining water, but by having that water available to recharge groundwater.
Did You Know
Wetlands can help buffer storm surges. A recent study by the U.S. Army Corps of Engineers indicates. Studies in the midwest show flood water flows can be reduced by 80 percent in watersheds with wetlands, as opposed to those without them.