Swamps, marshes, lagoons, river margins and estuaries, floodplains, and other wetland areas have historically been regarded as wastelands and have routinely been drained and converted to drier, more "productive" agricultural and industrial sites. For example, only 6% of California's original wetlands, 2% of Iowa's original wetlands, and less than 10% of the wetlands once along the shores of Lake Ontario remain today. Wetlands are, however, far from the wastelands they were once thought to be. Consider that the plants, algae, and other organisms in just 1 hectare (2.47 acres) of tidal wetland can perform the same recycling functions that about $150,000 of the latest wastewater treatment equipment is capable of—at no cost to taxpayers. The wetlands, at the same time, provide habitat, shelter, and breeding grounds for a wide variety of wildlife, many species of which are now threatened with extinction (Fig. 25.1).
Some attitudes toward wetlands have begun to change as the public has slowly become aware of the folly of eliminating them. City and regional planners in many areas now either ban new developments on wetlands or require a proposed development that would encroach on a wetland to provide mitigation measures such as the creation of new wet areas equal in extent and quality to those that may be lost. In addition, projects now in progress in many areas involve the restoration of damaged or lost wetlands.
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This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.