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Wetlands Preservation
Green Ballot works toward the preservation of all types of freshwater resources from rivers to lakes to wetlands. The pollution of rivers and lakes to the extent that birds can no longer safely use them for drinking without becoming contaminated, is of the highest concern. Similarly, pollution of these wetlands to the extent that fish and riparian species can no longer dwell in these rivers and lakes without becoming ill, will mark the end of biological diversity on this planet.
In this section of Green Ballot we address the narrower definition of wetlands, which includes muskegs, swamps, marshes, fens, moors, bayous, sloughs, vernal pools, and so on. Each type of wetland has characteristics specific to its own region. Two famous American wetlands are the Everglades and the Okefenokee Swamp. More than one-third of the federally listed species on the Endangered Species Act rely directly, or indirectly, on wetlands for their survival. Wetlands are generally regulated under the Clean Water Act and the Rivers and Harbors Act. In addition, some states and counties also have their own wetland protections in place. Internationally, the Ramsar Convention on Wetlands of International Importance recognizes a small fraction of the world’s significant wetlands and works to conserve them. Nevertheless, wetlands in the USA and abroad are disappearing rapidly are under constant threat from multiple directions.
The Functions of Wetlands
According to the Defenders of Wildlife, wetlands are the link between land and water, and are some of the most productive ecosystems in the world. Wetlands are often filled with trees, grasses, shrubs, moss, and other vegetation. To be called a wetland, an area must be filled or soaked with water at least part of the year.
Wetlands have a number of essential functions including:
Providing habitat for a wide variety and number of wildlife and plant species.
Filtering, cleaning and storing water; collecting and holding flood waters; and absorbing wind and tidal forces.
Wetlands also act like sponges by holding flood waters and keeping rivers at normal levels. Wetlands filter and purify water as it flows through the wetland system. Plants found in wetlands help control erosion.
As a result of development, population increase, drought, pollution, resource extraction, the expansion of agriculture, and contamination from industrial activities, wetlands are under extreme threat throughout the world. Over the past century, the United States has lost over half of its wetlands in the lower 48 states, and the losses continue at an estimate of over 60,000 acres per year.
The life-supporting importance of wetlands was largely unrecognized in the past. People drained, dredged, dammed and channeled wetlands, eliminated or converted them into dry land or filled them for lakes and water retention areas -- changing wetlands into cropland, pasture and subdivisions, mining the underlying resources, ridding insect life, filling in for road beds or flooding them for open water lakes, and using them for dumping grounds for waste and sewage.
Destruction of the Mississippi River Valley Wetlands
In an article published by the Environmental Law Institute, Professor Robert Stavins of Harvard University discusses how federal and state investments have accelerated the depletion of wetlands in this country. According to Stavins, private land-use decisions are often affected dramatically by public investments in highways, waterways, flood control, or other infrastructure. The large movement of jobs from central cities to suburbs in the postwar United States and the destruction of Amazon rain forests have occurred with major public investment in supporting infrastructure.
Private land-use decisions can generate major unintended environmental consequences such as the depletion of forested wetlands in the Mississippi Valley — an important environmental problem and a North American precursor to the loss of South American rain forests. These private land use decisions were exacerbated by federal water-project investments, despite explicit federal policy to protect wetlands. The largest remaining wetland habitat in the continental United States is the bottomland hardwood forest of the Lower Mississippi Alluvial Plain.
The Mississippi Valley wetlands, originally covered 26 million acres in seven states, but this resource was reduced to about 12 million acres by 1937. By 1990, another 7 million acres had been cleared, primarily for conversion to cropland. Needless to say, landowners typically do not consider the positive environmental externalities generated by wetlands; thus conversion may occur more often than is socially optimal. Such externalities are the motivation for federal policy aimed at protecting wetlands, as embodied in the Clean Water Act. Nevertheless, the federal government has engaged in major public investment activities, in the form of Army Corps of Engineers and Soil Conservation Service flood-control and drainage projects, which appear to make agriculture more attractive and thereby encourage wetlands depletion.
The significance of this effect had long been disputed by the agencies which construct and maintain these projects; they attributed the extensive conversion exclusively to rising agricultural prices. An econometric analysis of data from Arkansas, Mississippi, and Louisiana, from 1935 to 1984, sought to sort out the effects of federal projects and other economic forces. It was found that these public investments were a very substantial factor causing conversion of wetlands to agriculture, with 30 to 50 percent of the total wetland depletion over those five decades due to federal projects.
Professor Stavins highlights his conclusions regarding wetlands loss and government policy. First, landowners had responded to economic incentives in their land-use decisions. Second, construction of federal flood control and drainage projects caused a higher rate of conversion of forested wetlands to croplands than would have occurred in the absence of projects, leading to the depletion of an additional 1.25 million acres of wetlands. Third, federal projects had this impact because they made agriculture feasible on land where it had previously been infeasible.
The analysis highlighted a striking inconsistency in the federal government’s approach to wetlands. Through policies, laws, and regulations, the government recognized the positive externalities associated with some wetlands, with the George H. W. Bush administration enunciating a “no net loss of wetlands” policy. But public investments in wetlands — in the form of flood control and drainage projects — had created major incentives to convert these wetland areas to alternative uses. The government has been working at cross-purposes regarding wetlands conservation.
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The Attacks Upon Wetlands
A Recent study from the Water Quality Group at North Carolina State University shows that the quantity and quality of wetlands are under attack from every conceivable angle.
In the 1600's, over 220 million acres of wetlands existed in the lower 48 states. Since then, extensive losses have occurred, with many of the original wetlands drained and converted to farmland. Today, the great majority of the nation's original wetlands have disappeared. Activities resulting in wetlands loss and degradation include: agriculture; commercial and residential development; road construction; impoundment; resource extraction; industrial siting, processes, and waste; dredge disposal; tree harvesting; and mosquito control. The primary pollutants causing degradation are sediment, nutrients, pesticides, salinity, heavy metals, weeds, low dissolved oxygen, pH, and selenium.
Twenty-two states have lost at least 50 percent of their original wetlands. Indiana, Illinois, Missouri, Kentucky, and Ohio have lost more than 80 percent of their original wetlands, and California and Iowa have lost nearly 99 percent. Since the 1970's, the most extensive losses of wetland acreages have occurred in Louisiana, Mississippi, Arkansas, Florida, South Carolina, and North Carolina. Is it any wonder that the ivory-billed woodpecker (shown on the Green Ballot homepage) has not had an official siting since 1987? Between the mid-1970's and the mid-1980's, approximately 4.4 million acres of inland freshwater wetlands and 71,000 acres of coastal wetlands were destroyed. Inland forested wetlands were impacted the most during the mid-1970's to the mid-1980's, with a loss of 3.4 million acres, primarily in the Southeast. Approximately 900,000 acres were converted from forested wetlands to other wetland types.
Conversion to agricultural usage of land was responsible for 54 percent of the losses of both freshwater and coastal wetlands; drainage for urban development for 5 percent and "unspecified usage" (planned development) was responsible for 41 percent of the losses. This is in contrast to the mid-1950's to mid-1970's, when agricultural drainage of wetlands was responsible for 87 percent of the losses and urban development for 8 percent.
The Chemistry and Biology of Wetlands Degradation
Although wetlands can improve watershed water quality, their capacity to process pollutants without becoming degraded, is limited. Many wetlands have suffered functional degradation, although it is difficult to calculate the magnitude of the degradation. Wetlands are threatened by air and water pollutants and by hydrologic alteration. The major causes of wetlands loss and degradation include:
Hydrologic Alterations such as channels, levees, and drainage – In Louisiana, coastal areas are subsiding as a result of redirection of sediment by the Mississippi River. As the coast subsides, sea levels rise and cover the land. Saltwater intrusion into freshwater wetlands causes shifts in the plant and animal community. Saltwater intrusion causes habitat loss and fragmentation which threaten the fishery industry and the trapping business. This also results in a loss of genetic integrity when isolated habitats are too small to support viable populations. It also supports increased numbers of competitor, predator, and parasite species that are tolerant of these disturbed environments.
High sediment loads entering wetlands through channels, irrigation ditches and drainage ditches can smother aquatic vegetation, shellfish beds and tidal flats, fill in riffles and pools, and contribute to increased turbidity. Channel modification alters water temperature and diminishes habitat suitable for fish and wildlife.
Impoundment of natural wetlands for stormwater management alters the natural wetlands' hydrology and decreases water circulation. This leads to increased water temperatures, lower dissolved oxygen levels, and changes in salinity and pH; prevents nutrient outflow; and increases sedimentation. Sedimentation reduces the water storage capacity, reduces light penetration, reduces oxygen content and affects the entire ecosystem richness, diversity, and productivity. Toxic substances may accumulate in impoundments as a result of decreased water circulation and bioaccumulation of contaminants by wetland biota may occur. Impoundments are often invaded by non-native plant species such as common reed and purple loosestrife which out-compete the native species and change the wetland community structure.
Urbanization is a major cause of wetlands impairment resulting in loss of wetlands acreage and degradation of these wetlands. These are associated with construction activities and storm water runoff.
Impervious surfaces such as roads, buildings, and parking lots prevent rainfall from percolating into the soil. Rainfall and snowmelt that do make it to the soil now carry sediments; organic matter; pet wastes; pesticides and fertilizers from lawns, gardens, and golf courses; heavy metals; hydrocarbons; road salts; and debris into. Impervious surfaces decrease ground water recharge within a watershed and reduce water flow into wetlands.
Wastewater treatment plant effluent is a source of pollutants that continue to degrade wetlands. The "aging" of wetlands can occur when wetlands filter organic matter and heavy metals. Aging is the saturation of the ecosystem by nutrients and heavy metals over time that results in the reduced effectiveness and degradation of the wetland. Currently, for example, over one-third of shellfish waters in the USA cannot be harvested because of habitat degradation, pollutants, algal blooms, and pathogens. The heavy metals that have bioaccumulated in estuarine wetlands have caused deformities, cancers, and death in aquatic animals as well as in their terrestrial predators.
Urban and industrial stormwater, sludge, and wastewater treatment plant effluent, rich in nitrogen and phosphorus, can lead to algae blooms in estuaries. Algae blooms deplete dissolved oxygen, leading to mortality of benthic organisms. Some algae are toxic to aquatic life. Excess algae can shade underwater sea grasses, preventing photosynthesis and resulting in sea grass death. Because sea grass meadows reduce turbidity by stabilizing sediments and provide critical food, refuge, and habitat for a variety of organisms, including many commercially harvested fish, the death of these plants profoundly impairs the estuarine ecosystem.
Roads and bridges are frequently constructed across wetlands since our economy has put such a low value on wetlands. It is often considered to be more cost effective to build roads or bridges across wetlands than around them. Roads can disrupt habitat continuity, driving out more sensitive, interior species, and providing habitat for hardier opportunistic edge species and non-native species. Roads can impede the movement of certain species or result in increased mortality for animals crossing them.
Landfills can pose an ecological risk to wetlands. Landfill construction may alter the hydrology of nearby wetlands. Leachate from solid waste landfills often has high biological oxygen demand (BOD), and ammonium, iron, and manganese in concentrations that are toxic to plant and animal life. Researchers who conducted a study of the proximity of 1,153 sanitary landfills to wetlands in 11 states, found that 98 percent of the sanitary landfills were 1 mile or less from a wetland, and 72 percent were 1/4 mile or less from a wetland!
Wetlands can be invaded by aggressive, highly-tolerant, non-native vegetation, such water hyacinth and salvinia, or can be dominated by a monoculture of cattails or common reed. Water hyacinth and similar species can rapidly fill a wetland and are a threat to water quality in some areas. Carp and nutria are two introduced exotic animal species that degrade wetlands. Carp, introduced for recreational fishing, severely increase the turbidity of water resources. Nutria, introduced for their pelts, are rodents that voraciously eat, as well as destroy, freshwater and coastal wetland vegetation.
Marina construction and dredging activities can contribute suspended sediments into waters adjacent to wetlands. Boating activity can increase turbidity and degradation of wetlands. Wetlands can be adversely affected by pollutants released from boats and marinas. Pollutants include: hydrocarbons, heavy metals, toxic chemicals from paints, cleaners, and solvents. Dumping of wastes from fish cleaning and discharge of human waste from marinas and boats can increase the amount of nutrients and organic matter in a wetland. The increased organic matter and nutrients can lead to eutrophication.
The adverse effects of industry on wetlands can include: reduction of wetland acreage, alteration of wetland hydrology due to industrial water intake and discharge, water temperature increases, point and nonpoint source pollutant inputs, pH changes as a result of discharges, and atmospheric deposition. Hydrocarbon inputs can alter reproduction, growth, and behavior of wetland organisms, and can result in mortality. Plants suffocate when oil blocks their stomata.
Superfund sites can include toxic wastes, radioactive compounds, acids, heavy metals and other contaminants. These can all degrade wetlands habitat. Metals and radionuclides tend to concentrate in wetlands sediments and peat. Intake of very low concentrations of radionuclides, such as uranium, from a water supply, for instance, will cause kidney failure and death . If radioactive peat or peat with a high metal concentration is used for gardening or agricultural activities, it can pose a human health risk as well.
Historically, agriculture has been the major factor in freshwater and estuarine wetland loss and degradation. Although the passage of the Food Security Act of 1985 "Swampbuster" provision prevented the conversion of wetlands to agricultural production, certain exempted activities performed in wetlands can degrade wetlands. These include: harvesting food, fiber, or forest products; minor drainage; maintenance of drainage ditches; construction and maintenance of irrigation ditches; construction and maintenance of farm or forest roads; maintenance of dams, dikes, and levees; direct and aerial application of damaging pesticides (herbicides, fungicides, insecticides, fumigants); and ground water withdrawals. These activities alter wetland hydrology, water quality, and species composition. Excessive amounts of fertilizers and animal waste reaching wetlands in runoff from agricultural operations, including confined animal facilities, can cause eutrophication.
Wetlands provide critical habitat for waterfowl populations. The drainage of U.S. and Canadian prairie potholes for agricultural production has been linked to a 50% - 80% decline in waterfowl populations since 1955. Since the Swampbuster legislation was promulgated, the waterfowl population decline has begun to level off. Swampbuster rendered drainage of prairie potholes costly, and encouraged farmers to allow prior converted wetlands to revert to their previous natural wetland state and to construct farm ponds or restore marshes. Duck populations in 1994 increased over 1993 populations, and were the highest since 1980, when duck populations had plunged to a low.
Irrigation ditching can increase contamination of wetlands receiving irrigation drainage water, particularly where soil is alkaline or contains selenium or other heavy metals. Untreated runoff containing extremely high concentrations of selenium has led to mortality and deformities in bird, amphibian, and fish embryos and the disappearance of species from wetlands in California.
Grazing livestock can degrade wetlands that they use as a food and water source. Urea and manure can result in high nutrient inputs. Cattle traffic may cause dens and tunnels to collapse. Overgrazing of riparian areas by livestock reduces streamside vegetation, preventing runoff filtration, increasing stream temperatures, and eliminating food and cover for fish and wildlife. As vegetation is reduced, stream banks can be destroyed by sloughing and erosion. Streambank destabilization and erosion then cause downstream sedimentation, impairment of aquatic life, and a decrease in wetland habitat.
Timber harvesting has also destroyed wetlands. Adverse effects of logging include a rise in water table due to a decrease in transpiration; soil disturbance and compaction by heavy equipment; sedimentation and erosion from logging decks, skid trails, roads, and ditches; and drainage and altered hydrology from ditching, draining, and road construction.
Peat mining not only removes peat from wetlands, but requires clearing of vegetation, drainage of the wetland, and creation of roads for equipment access to harvest the peat. These activities destroy the portion of the wetland selected for harvest and degrade adjacent areas.
Phosphate mining has resulted in the loss of thousands of acres of wetlands in central Florida. Other types of mining operations can also degrade wetlands through hydrologic alterations, high metal concentrations, and decreased pH. Acid drainage from active and abandoned silver, gold, zinc, copper and other mines causes extensive ecological damage to wetlands, rivers, and lakes. Acid mine drainage introduces high levels of acidity and heavy metals into the wetland environment through runoff and through direct drainage from mines into wetlands. The acidity and the high metal concentrations alter the biotic community composition and can result in mortality. Acid from mining is often unseen above the ground but it is causing enormous environmental damage in wetlands and beneath the earth’s surface. (Remember the gold mine spill into the Las Animas River in 2015.)
Taking Action
Preserving wetlands is essential for protecting endangered and threatened species, and for conserving wildlife habitat. The Defenders of Wildlife offers a Citizen Advocate Handbook that is a guide in wetlands preservation efforts. The handbook provides tips for effective advocacy related to communicating with elected officials; working with the media; reaching out to your community; and raising the visibility of wildlife conservation efforts. Green Ballot can also be a resource regarding wetlands preservation issues, and we can be reached through our contact page.