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 Wetlands Functions (or Processes) and Values


Many people use the terms functions and values interchangeably when discussing wetlands, even though functions and values are different. Functions are the physical, chemical, and biological processes occurring in and making up an ecosystem. Processes include the movement of water through the wetland into streams or the ocean; the decay of organic matter; the release of nitrogen, sulfur, and carbon into the atmosphere; the removal of nutrients, sediment and organic matter from water moving into the wetland; and the growth and development of all the organisms that require wetlands for life.

Values are "an estimate, usually subjective, of worth, merit, quality, or importance" (Richardson 1994). Wetland "values" may derive from outputs that can be consumed directly, such as food, recreation, or timber; indirect uses which arise from the functions occurring within the ecosystem, such as water quality, and flood control; possible future direct outputs or indirect uses such as biodiversity or conserved habitats; and from the knowledge that such habitats or species exist (known as existence value) (Serageldin 1993).

The difficulty with determining the value of a wetland is that valuation can be a subjective assessment, particularly the valuation of indirect use, future use, or existence values. Some wetlands may have multiple uses or worth. Wetlands that are remote may not directly benefit any humans but may be critical, for instance, to the existence of a type of salamander. People may value the intangible fact that wetlands exist, but would not be able to place a price on them, perhaps feeling offended by the concept. In contrast, the value of estuaries in producing shrimp can be calculated based on the price of shrimp.

Conflicts may also arise between public and private valuation. For example, although an individual landowner may not receive the financial benefits of the wetland on his or her property, it may have worth to the town or county in improving public water quality or quantity. In such a case, the town or county could pay the landowner to preserve a wetland. In more complex cases involving endangered wetland species found on private property, the government attributes a value to the preservation of the species and regulates the development of the private property, although the property owner may not value the organism at all or values it less than he does other possible land uses.

Within watersheds and ecosystems, human activities can cause depletion or pollution. The watershed and its ecosystems sustain our way of life, regardless of our understanding of the biology, chemistry, and geology involved. However, when decision makers do not understand the basics of ecosystem functions and values, they may make choices that prevent ecosystems from fully functioning. The result may be long term and possibly irreversible changes. Such changes reduce the value of the ecosystem. They can even affect the economy. A familiarity with the functions and values of an ecosystem such as a wetland can improve decision making today and protect values that may be held by future generations as well.