Wetlands are geographical areas always covered by water at varying depths at different times throughout the year. The amount of water present in these environments controls the type of flora and fauna living in and on the soil. Wetlands support both aquatic and terrestrial organisms but favor the growth of organisms that are specifically adapted for the development of unique characteristic wetland soil.
The Environmental Protection Agency (EPA) determines wetlands ecosystems based on the Classification of Wetlands and Deepwater Habitats in the U.S. This system is used by the U.S. Fish and Wildlife Service for the National Wetland Inventory. Overall, the five types of wetlands are classified by landscape, vegetation coverage and the amount and temperature of water types present throughout the year, which include: marine, tidal, lacustrine, palustrine, and riverine. Although there is a second wetland classification system, it is primarily used by the Army Corps of Engineering and evaluates wetlands based on the geomorphic setting, water source and hydrodynamics.
"Marshes have a continual supply of surface water and groundwater."
Wetlands are also referred to as marshes, swamps, bogs and fens. Marshes have a continual supply of surface water and groundwater. Marshes typically have a neutral pH and extremely valuable nutrients that lead to an abundance in plant and animal life. Swamps are wetlands that are primarily dominated by woody trees and characterized by the species of tree. There are many types of swamps that are classified based on the type of woody trees that dominate the ecosystem.
Swamps are characterized by nutrient-rich saturated soils and a diversity of water tolerant trees, vertebrate and invertebrate organisms as well as rare species such as the American crocodile. Bogs are a very unique wetland with spongy peat deposits, acidic waters and grounds covered by moss. Most of the water available to bogs is from precipitation, which leaves them with limited nutrients for plant growth. The last and lesser-known type of wetland is the fen. Fens are very similar to bogs, but instead of getting water from precipitation, fens' water sources are supplied from groundwater and drainage from differing elevation. This allows fen ecosystems to have more nutrient-rich soil and less acidic water, allowing a greater diversity of plant and animal life.
The benefits of wetlands
Wetlands play a crucial role in water supplies around the world. Marshes refuel groundwater supplies and control the flow of water into streams, which is extremely valuable during periods of limited rainfall. Marshes, swamps, bogs and fens all reduce damage done during floods by slowing and storing flood waters before they reach the watershed. These ecosystems are usually very high in nutrients, which can pollute surface water with nitrogen and phosphorus from run-off. However, plants and animals in these communities use the excess nutrients for growth.
All wetlands provide unique and diverse ecosystems to the multitude of organisms inhabiting them. Each environment also provides characteristics that are suitable for specific organisms. Wetland acreage has been decreasing greatly, and although there are laws in place to replenish these ecosystems, it takes hundreds to thousands of years for wetlands to become fully restored. Currently, restoration is not possible with the rate at which they are being overhauled by builders and developers. Many wetlands are also sources of stored atmospheric carbon dioxide, which have only recently been recognized for the role they play in the carbon cycle and regulating the global climate.
Development and the future of the wetlands
In Madison, Wisconsin, wetland destruction has increased in the last 10 years due to a controversial state law that reduced regulations for protecting important ecosystems. Initially when Wisconsin was being settled, government officials wanted to fill in or drain much of the 5.3 million acres of wetlands across the state. In the 1970s, many regulations were established to control wetland fills as well as commercial and residential development. In June 2012, a revision of the standards and procedures used by the Wisconsin Department of Natural Resources was rewritten and became Act 118. The new regulations made it easier for builders and developers to get permits as well as allow for greater consideration in establishing new wetlands in a different location.
Today, many of the wetlands that were supposed to be reestablished in new locations have not been developed by builders and other professionals that obtained permits. As of June 2012, over 1,180 acres of wetlands have been destroyed by building. This number is more than double the acreage developed over the last five years. Jennifer Sereno, a Wisconsin Department of Natural Resources spokesperson, stated that although it seems there are more acres being developed, the number of requests has decreased since Act 118 became effective.
"Water quality consultants are needed to determine the toxins found in these aquatic environments."
Many scientists are concerned that even with the replacement wetlands, they will not be effective enough to remove pollutants out the water supplied to lakes, streams and aquifers. Experts are also concerned that the "new" wetlands being developed will not be able to maintain the plant and animal species that depend greatly on these wetland ecosystems.
"More wetlands are being created than are being destroyed (nationally), which is good news until you look at the fine print, which was most of the ones being created are shallow ponds, sedge meadows take millennia to create," Quentin Carpenter, a senior lecturer at the University of Wisconsin-Madison's Nelson Institute for Environmental Studies, explained to the Chippewa Herald. "There's no way to hurry that process."
Impact on water quality
With the destruction of many wetland ecosystems throughout Wisconsin and the U.S., it's important to remember that wetlands filter many of the toxic pollutants out of water used by local residents. Much of the water supplied by the wetlands goes into local streams and lakes, which then flows into aquifers. Water quality consultants need to determine the toxins and pollutants found in these aquatic environments and continue to monitor changes in concentrations in the newly developed wetlands compared to existing wetlands. This will provide a better understanding of how effective the replacement wetlands are compared to the existing wetlands that have been developing for hundreds and thousands of years.