Wetlands provide many hydrologic, ecological and biogeochemical functions. They play important roles in maintenance of water reserves and quality, recharge of groundwater, cycling of nutrients, sequestering of carbon, and production of food that supports entire food chains. By supplying pockets of shallow water with an abundance of food, wetlands serve as the major nurseries for many fish, amphibians, invertebrates and waterfowl. They serve as critical habitat for many unique types of wildlife. They house biodiversity that compares with that of coral reefs or tropical rainforests. Plant productivity of the world's fresh water wetlands is matched only by tropical rain forests; that of salt marshes is unsurpassed by any other ecosystem. Indeed, wetlands are global workhorses. In addition, they provide recreational opportunities for people to view and photograph wildlife, hike, boat, hunt, fish, and enjoy their natural beauty.

Wetlands function like sponges, storing water (floodwater, or surface water that collects in isolated depressions) and slowly releasing it. Trees and other wetland vegetation help slow floodwaters. This combined action, storage and slowing, can lower downstream flood heights and reduce the water's erosive potential, and allow for the recharge of groundwater protecting the quantity and quality of potential drinking water. Studies have shown that the presence of wetlands in a floodplain can reduce flood peaks by 80 percent. Preserving and restoring wetlands can often provide a level of flood control that would otherwise require expensive dredging operations and levees. The bottomland hardwood- riparian wetlands along the Mississippi River once stored at least 60 days of floodwater. Now they store only 12 days because most have been filled or drained. By slowly releasing water, wetlands not only protect against floods, but also droughts. If all the water in a system is shunted to sea as quickly as possible through constricted leveed floodplains, then baseflow levels are not maintained during dry summer and fall months. This has an impact on municipal water supplies, and many fish species.

The economic value of this function is considerable. It is estimated that storm and flood damage exceeds $1 billion annually in the United States. In addition to moderating flood peaks, wetlands stabilize landforms, and by slowing water velocities, protect areas from erosion. In Massachusetts, floodplain wetlands were deemed so effective for flood control by the U. S. Army Corps of Engineers that they purchased many wetlands rather than build expensive flood control structures. The Louisiana coastal marshes are being destroyed at an alarming rate due to subsidence and saltwater intrusion because the nutrient rich water and sediments no longer flow through the marshes, but out to sea.

Some wetlands recharge groundwater, which is a common drinking water source. Surface water in these wetlands percolates down through the soil beneath the wetland and enters the groundwater or aquifer. Some studies have shown wetlands to be more important than uplands to groundwater recharge.

Wetlands also improve the quality of water. Wetlands have been shown to remove organic and inorganic nutrients and toxic materials from the water that flows across them. When environmental conditions are optimal, waste organic compounds are rapidly decomposed, and the accumulated heavy metals and phosphorous are buried in deep sediments. In Arkansas and other states in the Mississippi River basin, the water quality of some rivers, streams, and bayous has been degraded due to the runoff from surrounding lands. This means that more nitrogen fertilizer is running off farmland directly into the river and into the Gulf of Mexico. The cumulative effect of this influx of nitrogen is a large area of the Louisiana continental shelf with seasonally-depleted oxygen levels (the hypoxic zone). Excess nutrients lead to increased algal production and increased availability of organic carbon within an ecosystem, a process known as eutrophication. When these algae die and organic material accumulates, the metabolism of the decomposer organisms uses all the oxygen stored in the water. Most aquatic species cannot survive at such low oxygen levels. The hypoxic zone forms in the middle of the most important commercial and recreational fisheries in the coterminous United States and could threaten the economy of this region of the Gulf.

Wetlands are among the most biologically productive natural ecosystems in the world. The microbes, plants, and wildlife residing in wetlands are part of global cycles for water, nitrogen, and sulfur. In addition, wetlands store carbon within their plant communities and soil instead of releasing it to the atmosphere as carbon dioxide. They contribute to the stability of global levels of available and atmospheric nitrogen, atmospheric sulfur, carbon dioxide, and methane. Thus wetlands help to moderate global climate conditions and function in atmospheric maintenance.

Wetlands can be compared to tropical rain forests and coral reefs in the diversity of species they support. Wetlands produce great volumes of food as leaves and stems break down in the water; this enriched material is called detritus. Detritus is food for insects, shellfish, and forage fish, and it provides nutrients for wetland plants and algae. Large fish, as well as mammals, birds, reptiles, and amphibians, eat aquatic invertebrates and forage fish. Wetland plants provide shelter and food to diverse species. Wetlands also provide essential breeding, nesting, feeding, and predator escape habitats for millions of waterfowl, other birds, mammals, and reptiles. Well over one third of the 564 plant and animal species listed as threatened or endangered in the United States utilize wetland habitats during some portion of their life cycles. In Arkansas, wintering waterfowl depend on bottomland hardwood forests for acorns and invertebrates. Prothonotary warblers prefer nest sites within or near wetlands. Fish species depend on wetlands for nutrients and spawning and nursery grounds. Hydrology is a major determinant in the use of and adaptation to bottomland hardwood wetlands by wildlife. Varying flooding regimes and slight elevational changes provide a habitat continuum supporting a range of aquatic and terrestrial species, including canopy dwellers.

Arkansas wetlands, especially those in the Mississippi River Delta, are critical components of the series of wetlands along the Mississippi Flyway. This flyway is sometimes referred to as the "mallard flyway," because more than 1 million mallards typically winter in its lower reaches. They are so important, in fact, that wetlands in the Cache-Lower White River system have been designated as one of only seventeen "Wetlands of International Importance" in the United States by the RAMSAR Convention on Wetlands, on par with such famous wetlands as the Everglades.

Wetlands are vital to commercial and recreational sectors of our economy. In addition to the economic benefits of flood and drought protection, groundwater recharge, water quality maintenance, and atmospheric maintenance, wetland plants and animals have an economic, as well as ecological benefit. Wetlands, especially bottomland forests, supply timber for the Nation's logging industry. It is estimated that the bottomland hardwood and cypress swamps of the Southeastern part of the United States are worth over $8 billion and climbing. Moreover, the sports fishing industry and the waterfowl hunting industry are also dependent upon the continued productivity of our wetlands. More than half of all U.S. adults hunt, fish, bird-watch or photograph wildlife, spending a total of $59.5 billion annually. Waterfowl hunters spend over $630 million annually to harvest wetland-dependent birds, with a large percentage of this money going directly to wetland habitat protection. In addition, wetlands' diverse plant and animal life make them a valuable resource for non-consumptive recreation such as hiking, bird watching and photography. Fifty million people spend an estimated $10 billion each year observing and photographing wetland-dependent wildlife. Wetlands provide educational and research opportunities, as well as a perspective on historical and archaeological values.

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