Artificial wetlands may perform quite well in certain tasks, such as wastewater treatment, but are unlikely to surpass natural ecosystems on more general grounds of resilience and biodiversity. Restoration projects, similarly, work best in bringing back simpler kinds of wetlands, but have a poorer track record when it comes to reestablishing more complex ecosystems that support rare species. Therefore, preserving our remaining wetlands should be our primary goal, given that natural systems have a clearcut edge over their man-made counterparts, with millions of years of evolution behind them.
In April 2001, the Bush administration upheld a ruling by President Clinton to close a loophole that had allowed contruction companies to work in wetland areas without government approval. Because of this loophole, an estimated 20,000 wetland acres were needlessly destroyed. This act is clearly a step in the right direction, but we cannot just protect our wetland sites and leave it at that. Wetlands function within a larger landscape, upon which they are dependent for water, nutrients and animals. The watershed that sustains inland sites has to be taken into account in any successful preservation effort. In the same way, corridors are needed so that animals like frogs, beavers and muskrats can gain access to wetland zones and move about freely. Many plants that birds depend on, for example, are pollinated by bees that nest in drier areas. So it is important to consider the broader ecological setting in our efforts to protect or restore wetlands.
Size is another important factor, as studies have shown that breaking up ecosystems into smaller and smaller parcels - an all too common practice today - can lead to the extinction of species, thereby reducing diversity and resilience. Fragmentation has other, less obvious, consequences.
Although a major flood may be well tolerated in a large riverine wetland, a flood of the same magnitude could kill all the animals in a small, restored wetland. Under natural conditions, floods occur in a big landscape where there are refuges for animals and plants. Unfortunately, this is not the case in some of the small isolated wetlands we see today.
Our perspective on wetlands is slowly changing. Once considered wastelands that did little more than provide safe havens for mosquitos, poisonous snakes and other undesirables, scientists can now catalog a broad range of vital services these regions provide in terms of water quality and flood control, among other benefits. Wetlands are also places of uncommon beauty, critical to the survival of scores of endangered species. An appreciation of the value of our soggy zones has come belatedly. The question now facing us is whether we can act in time to head off the bulldozers, poised for destruction in the name of "progress."
More than half of the wetlands in the United States have been lost to human activities and as much as 90 percent of the wetlands in states such as California and Ohio have been wiped out.