CW2:9219

From Environmental Technology

Current revision as of 05:01, 13 February 2006

1. A.Wetland refers collectively to marshes, swamps, bogs and similar areas found between dry land and water along the edges of streams, rivers, lakes, ponds, and coastlines and other bodies of water. Although most wetlands have standing or flowing water, many are dry for part of the year. For example, estuarine wetlands that are influenced by the tides may be dry twice a day. Several wetland types occur throughout the Chesapeake watershed due to its variability in typography, climate, soil, hydrology, salinity, vegetation and other factors.

B. Estuarine wetlands are tidally flooded by salt or brackish water and are found chiefly along the shores of the Bay and its tidal rivers. Palustrine wetlands are freshwater areas, situated on the floodplains bordering rivers and streams, fringing the shorelines of lakes and ponds, filling isolated depressions and covering broad flat areas at or near sea level. Wetlands also are characterized by their vegetation, as: Emergent wetlands, commonly called marshes and wet meadows, dominated by grasses, sedges and other herbaceous or non-woody plants; Shrub wetlands, including shrub swamps and bogs, characterized by low to medium-height woody plants; and Forested wetlands, largely wooded swamps and bottomland hardwood forests.

2. Wetlands Protect and Improve Water Quality

Healthy wetlands remove and retain excessive nutrients, such as nitrogen and phosphorus, from the water. Forested riparian (or streamside) wetlands remove about 80 percent of the phosphorous and 90 percent of the nitrogen from water, which act as water contaminants and may result in unhealthy algae blooms. Wetlands also can minimize sediment loads and absorb chemical and organic pollutants before they can enter the Chesapeake Bay.

Wetlands Help Control Flooding and Erosion

Wetlands often have been referred to as natural sponges that absorb flooding waters. By temporarily storing floodwaters, wetlands help protect adjacent and downstream property owners from flood damage. Wetlands in urban areas are especially valuable for flood protection, since urban development increases the rate and volume of surface water runoff, thereby increasing the risk of flood damage. Wetlands are often located between rivers and high ground and, therefore, are in a good position to buffer the land against erosion. Wetland plants can reduce erosion by binding soil with their roots.

Wetlands Provide Habitat for Terrestrial and Aquatic Wildlife

Tidal estuarine and palustrine wetlands provide vital habitat for fish, shellfish, waterfowl, wading birds and mammals. Striped bass, menhaden, flounder, oysters and blue crabs are among the most commercially important fish and shellfish that depend on estuarine wetlands. Palustrine wetlands also provide valuable fish habitat and support a variety of birdlife, including ducks, geese and many songbird species. Mammals that are commonly found in wetlands include muskrat, white-tailed deer and beaver. Wetlands foster the production of many species including fish, shellfish and waterfowl, and plants such as wild rice and blueberry. Forested wetlands, which are the most common type of palustrine wetlands, supply valuable timber products.

3. More than 50percent of the original forest still remains.Forests once covered 95 percent of the watershed. Today, they cover about 60 percent, performing vital functions that benefit water and air quality. More than 50 major tree species and more than 2,700 different plant species grow in the Chesapeake Bay watershed. Many kinds of trees can live for 100 years or longer. Some species, such as oak, can live for 500 to 800 years.

4. Forests perform crucial functions that benefit the plants and animals throughout the Bay watershed. They:

• Protect Water Quality: Forests act as ‘sponges’ by capturing rainfall, reducing runoff, maintaining the flow of streams, filtering nutrients and sediment and stabilizing soils. Riparian forests that buffer streams significantly reduce the amount of excess nutrients that enter the water, sometimes by as much as 30 to 90 percent. Mature trees also provide deep root systems that hold soils in place, helping to stabilize streambanks and reduce erosion.
• Create Habitat for Fish and Wildlife: Healthy forests provide food, shelter, nesting sites and safe migration paths for the aquatic and land animals. Streamside forests shade the water beneath their canopies, maintaining cooler water temperatures in summer, an important factor for spawning fish. Decaying leaves and wood also are essential links in the Bay’s food chain.
• Improve Air Quality: Forests absorb or trap nitrogen, particulates and other pollutants in the atmosphere that are released by cars, factories, farming and construction.
• Encourage Recreation: Forests offer us places in which to reflect and experience natural beauty and solitude. They foster active outdoor recreation, such as fishing, hiking, camping and cross-country skiing. Tourism and recreation contribute to the region’s economy.
• Contribute to the Economy: Forests produce wood for paper, building materials, fabrics such as rayon, and even food and medicines. The forest products industry is an important source of jobs for rural areas and small cities in the Bay watershed. In Virginia alone, wood products contribute $9.8 billion annually to the state’s economy. Pennsylvania is the nation’s largest hardwood producer. And in Maryland, more than 41,000 people work in the wood products industry.

5. Plants and some bacteria can produce their own food through a process known as photosynthesis. Using energy from the sun, carbon dioxide and water are combined to form high-energy organic compounds. These organic compounds and other necessary chemicals form it's cellular structure, helping the plant to grow. Because of this ability to use carbon dioxide and sunlight to produce their own food, plants are called Autotrophs or self-feeders. They are the primary food producers. All other organisms must feed, directly or indirectly, on organic material produced by plants. Animals cannot process carbon via photosynthesis. Instead, they acquire carbon by eating the organic matter contained in plant and animal tissue or dissolved in water. The animal breaks this organic material down into com-ponents it can use for energy and growth. Animals are -Heterotrophs or other-feeders.

6. The growing of the human population also threatens fish by impairing water quality and depleting levels of dissolved oxygen. Between the 1930s and the 1980s, domestic and agricultural pollution increased water turbidity and phytoplankton production, which caused vast acres of submerged aquatic vegetation (SAV) to decline, thus reducing habitat and nesting areas for juveniles of many fish species. Nutrient pollution–from agricultural runoff, which elevates levels of nitrogen and phosphorus in Bay waters–continues to be a significant problem. Man-made stream blockages, such as dams and road culverts, prevent migratory species from reaching their historic spawning grounds. Complete removal of blockages or the construction of fish ladders at dam sites are two methods that the Bay Program supports to restore fish passage to the Bay’s stocks of migratory fish.

7. Wetlands disappearing is very crutial to the environment. It provides homes for many animals and it also serves as a boundary for the land and the water regions. If we lost the wetlands it cause great harm to the environment as a whole not just for the Chesapeake Bay area.