Wetlands are the main link between the land and the water, and as such are vitally important to the ecology. Wetlands have been misunderstood and abused throughout the history of the United States -- and elsewhere in the world -- and that has led to enormous environmental losses. This paper explores all pertinent information with regard to wetlands.
What are Wetlands?
The Environmental Protection Agency (EPA) defines wetlands as those "…transition zones where the flow of water, the cycling of nutrients," along with the sun's energy, all meet in order to create "…a unique ecosystem characterized by hydrology, soils, and vegetation" (EPA). The four categories of wetlands are swamps, bogs, fens and marshes. The EPA describes marshes as wetlands that are "…dominated by soft-stemmed vegetation"; swamps are quite different, as they are composed of "mostly woody plants."
As for bogs, they are freshwater wetlands that were formed by glacier-made lakes; bogs are dominated by "spongy peat deposits, evergreen trees and shrubs" with a floor featuring a "thick carpet of sphagnum moss" (EPA). The EPA defines fens as "freshwater peat-forming wetlands" that are noted for grasses, reeds, wildflowers and sedges.
What are the Essential Purposes of Wetlands?
The wetlands are known as "nurseries of life" because they offer habitat for literally thousands of species of animals and plants. When people generally think of wetlands they conjure up images of snakes, turtles, frogs, even alligators. But wetlands are far more dynamic than homes for those animals. Importantly wetlands offer habitat for mammals, fish, and in particular, waterfowl. In fact when birds migrate in huge numbers they use wetlands for rest and food on their way south for the winter. The EPA reports that about two-thirds of the ten to twelve million waterfowl in the U.S. "…reproduce in the prairie pothole wetlands of the Midwest.
But those are only a few of the positive reasons wetlands need to be supported and sustained by wise environmental planning and strategies. Wetlands help to reduce the damage that floods cause; when rivers overflow, for example, wetlands absorb a lot of that excels water and that reduces potential damage to property (EPA).
The EPA offers simple guidelines that citizens and elected public officials can follow in order to protect wetlands. Those guidelines and ideas are as follows: a) citizens can buy "duck stamps" (that cost $15) online at www.fws.gov; the money from the sale of these stamps goes to a fund that supports wetland acquisition and restoration; b) urge public officials to resist destroying wetlands by either draining or filling wetlands; c) when building homes near wetlands it is a good idea to plant native grasses or "…forested buffer strips along wetlands" that border one's property; d) offer to volunteer for a program that monitors wetlands; e) invite a "wetland expert" to come and offer a presentation at a school or other organization; f) if there is any question as to whether a certain small swampy area is a wetland, get technical assistance from competent, knowledgeable authorities (EPA).
How Many Acres of Wetlands are being Lost each Year?
The U.S. Department of the Interior has issued a report on a five-year survey that shows the loss of wetlands in the United States "…are slowing," and that is considered gain for conservation and for wildlife and habitat for wildlife. Interior Secretary Ken Salazar asserts in the report that "Wetlands are at a tipping point" because notwithstanding the slowing down of the destruction of wetlands, the country still is losing huge parcels of wetlands. The country has made "great strides in conserving and restoring wetlands since the 1950s," Salazar reports.
At that time the country was losing wetlands (to development and urban sprawl) at the rate of about half the size of Rhode Island annually. Still, even though the loss of wetlands has slowed, because the nation is still on a "downward" trend vis-a-vis wetland protection it is "alarming," according to Salazar.
Between 2004 and 2009, the United States loss an estimated 62,300 acres of wetlands; after that loss the U.S. still had a total of 110 million acres of wetlands (and that includes Hawaii and Alaska), the report continues. Ironically, while restoration activities by conservationists, governments and private parties increased the amount of restored wetlands "…by 17%" compared to the period 1998 to 2004, at the same time "…the wetland loss rate increased 140% during the same period" and hence, that wetland losses outpaced gains (Interior Dept).
The director of the Fish and Wildlife Service is Dan Ashe; he said that in the last five years the U.S. lost "…over 630,000 acres of forested wetlands" and most of those lost acres were in the Southeast, Ash said. The acreage lost amounts to "…half a million football fields each year" and this should be of great concern to citizens since wetlands help "…ensure good water quality for local communities and provides vital habitat for a diversity of important wildlife species," Ash continues on the U.S. Department of the Interior report.
The greatest wetlands loss has occurred in the Atlantic and Gulf of Mexico coastal plain, and particularly in the Lower Mississippi River region, the report continues. But there were also severe losses in the Great Lakes region, in the "prairie pothole region," and in areas of urban development across the country (think urban sprawl and cities extending out into wildlands), the report explained.
In addition to being a vitally important resource for wildlife, for plants and fishes, wetlands are important landscape features, the Fish and Wildlife Service report emphasizes, because wetlands "…hold and slowly release flood water and snow melt, recharge groundwater, act as filters to cleanse water of impurities, recycle nutrients, and provide recreational opportunities for millions of people."
Structural and Functional Loss in Restored Wetland Ecosystems
In an article in the peer-reviewed journal PloS Biology the authors assert that wetlands are the "most productive and economically valuable ecosystems in the world" (Moreno-Mateos, et al., 2012, p. 1). Sadly, human activities have had a severely negative impact on wetlands over the years. More than fifty percent of wetland ecosystems in China, Australia, Europe and North America were "lost" in the 20th century, the authors explain.
This loss of wetlands worldwide has created the need to restore some of those wetlands, and Moreno-Mateos and colleagues performed a meta-analysis of 621 wetland sites that have been restored -- or at least there was an attempt to restore them. The results of that meta-analysis show that "even a century after restoration efforts," the biological structure of the recovered wetlands was quite a bit lower than the "reference sites" (natural wetlands that have not been disrupted) (Moreno-Mateos, 1).
The meta-analyses used by the authors were conducted through the careful examination of 124 existing studies; in these studies the "ecological responses were measured at known time intervals since restoration" (Moreno-Mateos, 2). And from those 124 empirical research studies employed, the authors pulled out 1,501 "data points" that carefully compared the variables -- biological, biogeochemical and hydrologic -- in those supposedly restored wetlands. They asked the pertinent questions that scientists should ask: a) how fast are the biological and biogeochemical components of those restored ecosystems "…changing relative to less perturbed reference ecosystems?"; b) Are the changes noted "…trend towards or away from the pre-disturbed ecosystem or parallel control ecosystems?"; and c) is the recovery of previously disturbed wetlands dependent upon the size of the wetlands or on the environmental setting (the hydrologic connectivity or the regional climate)? (Moreno-Mateos, 2).
Specifically, the biological structure of the "restored" wetlands that the authors examined were "…driven mostly by plant assemblages," and the biological structure was on average 26% lower than what it was originally. As to the "biogeochemical functioning" in the 621 sites investigated, it was driven "primarily by the storage of carbon in wetland soils" and showed to be 23% lower in biogeochemical functioning than it originally was (Moreno-Mateos, 1). The authors believe that either the recovery of the original wetlands was very slow, or systems that grew there after the initial disturbance "…have moved towards alternative states that differ from reference conditions" (Moreno-Mateos, 1).
The wetlands that had recovered more quickly were those in warm climates (including tropical climates); and those that suffered from a much slower recovery were found in mostly colder climates. The higher recovery rates in warmer environments were due to the "accelerated ecosystem processes," Moreno-Mateos explains (1).
In analyzing the previous empirical studies, the authors learned that the amount of storage and "cycling" of carbon and nitrogen were "…drastically reduced from pre-impact levels after degradation" (Moreno-Mateos, 3). This finding was no surprise to the researchers because typically the disturbance and degradation of wetlands releases carbon dioxide into the atmosphere, which of course contributes to the greenhouse affect and in turn contributes to global climate change. Moreover, the future storage of carbon was shown to be "significantly lower" than previous to the disturbance. In other words, once a wetland area has been destroyed and then restored, the plants will never be able…