Wetland Values
When settlers arrived on this continent, they found a land of seemingly limitless natural resources. Among the wild rivers, virgin forests and endless prairies, were perhaps as many as 127 million acres of wetlands. Today, more than 50 percent of those wetlands are gone, and without protection, thousands of acres will be lost each year in the United States.
In Missouri the sad tale has been repeated, although on a smaller scale. Of the original 2.4 million wild-acres of forested lowlands in southeast Missouri, less than 60,000 acres, or 2 percent, remain today. A map of the riverways of the Bootheel reveals blue lines that are straight enough to be a prairie highway. They are not highways, however. They are man-made channels and drainage ditches that bear no resemblance to the meandering lowland streams and sloughs of the past. First it was lumbering brought by the railroads, then agriculture that was responsible for the clearing of those rich alluvial soils. The process, typical of man's stubborn diligence, took only 200 years to rob Missouri of its hardwood swamps.
Before the last decade, wetlands rarely were considered in terms other than their importance as wild-acres life habitat. Today, however, we are learning that wetlands perform many other valuable functions, such as filtering pollutants, recharging and stabilizing underground aquifers, moderating flood waters, governing the quantity and quality of flow of our water resources and producing valuable commercial crops. Wetlands also are recognized as important places of scenic beauty, providing recreation to millions of birdwatchers, hunters, fishermen and outdoor enthusiasts of all types.
As knowledge of wetlands increases, people are recognizing that, left in their natural state, wetlands are areas of important public value. After all, wetlands are the most productive ecosystems in the world. Two-thirds of the economically important fish and shellfish harvested in the Atlantic Ocean and Gulf of Mexico depend on coastal wetlands for their existence. These marine marshes produce more than 10 tons of organic materials an acre each year. That is about 20 times the amount produced in each acre of open ocean.
In freshwater the story is similar. Wetland areas are home to countless invertebrates, amphibians, reptiles, fish, birds and mammals. Some fish, such as northern pike, walleye and yellow perch, require shallow marshy areas for spawning. The failure of many aspects of commercial and recreational fishing in the Great Lakes has been linked to destruction of wetlands.
Wetland productivity also includes waterfowl and furbearing animals. Millions of ducks depend on wetlands scattered across the United States and Canada for their existence. As a direct result, two million waterfowl hunters participate in more than 15 million hunting days of recreation each year in the United States. Wetlands also constitute the principal habitat for producing the annual crop of furbearing animals. Missouri's fur resources produce substantial financial revenues each year.
Wetlands provide economic returns other than from the fish and wildlife they support. In their natural state, many wetlands produce crops of considerable value. For example, the annual crop of wild rice in Minnesota is valued at more than $1 million, and studies in neighboring states have revealed that many wetlands could be adapted to produce wild rice crops, also.
Closer to home, a commercially valuable wetland crop is wood. In Missouri's Bootheel, wetlands can support bald cypress, tupelo, sweet-gum and bottomland oaks. These trees--especially cypress because of its durability without preservative treatment--are valuable. Bottomland oaks and pecan are found throughout the state and are important wetland trees for lumber, nuts and wildlife foods.
Fish, frog and crawfish farming are other economic benefits from wetlands. There is a small but growing Missouri industry in this type of farming.
Another important aspect of wetlands is their function of reducing the pollution levels in water. Wetlands improve water quality by decreasing the level of soluble nutrients in the water flowing through them. This process is accomplished when plants take up pollutants, store them and then use them as nutrients. For example, excess nitrogen and phosphorus from farming have been responsible for reducing water quality in many streams and lakes. But wetlands, acting as buffers turn nitrogen into a gas. Wetland plants store nitrogen and phosphorus and use them for plant growth. When the plants die, the chemicals are slowly released. Wetland vegetation filters particles from water, reducing siltation of streams and rivers. This ability of wetlands to improve water quality has been used by municipalities and livestock feedlots to treat wastewater Columbia, Missouri has constructed a wetland system to provide secondary treatment of city wastewater. The effluent will then be utilized to provide flooding for wetland habitats managed by the Missouri Department of Conservation.
Image Right: Water circulates continuously in a natural system that includes wetlands. When water reaches the land it is taken up immediately by evaporation or plants, or it works its way to wetlands where the water table is at or just below the surface.
Wetlands also improve water quality by acting as settling basins for upland runoff. Because of their low gradient and thick vegetation, wetlands slow the flow of water entering them, allowing suspended soil particles to settle out. The water then is released into adjacent streams and underground supplies.
Another important function of wetlands is their role in flood control. Wetlands act as giant sponges made up of organic matter and specialized plants that can absorb up to 18 times their weight in water. During periods of heavy rains or runoff, the wetlands' soaking action holds water and releases it slowly back into the watershed. By retaining water and releasing it gradually, wetlands reduce the total amount of water entering lower watersheds and consequently reduce flood risk and peak flood flows. Wetlands also tend to reduce erosion by stabilizing soils and reducing stream velocity.
The unique role of wetland ecosystems in food production, pollution control, water quality improvement, flood and erosion reduction, and replenishment of groundwater supplies is just beginning to be understood and appreciated. Because of the great number and variety of life forms they support, wetlands provide many hours of outdoor recreation, plus educational and scientific research opportunities.
As human populations increase and progress trudges on, the pressure for converting wetlands to agricultural production, urban development and other uses will increase. One of the best ways to guarantee the protection of our remaining wetlands is to understand how the important values of wetlands serve mankind.
