ABSTRACT
Everyone has a vague idea of what constitutes a wetland, but not everyone has the same idea. In a geological sense, natural wetlands are an ephemeral component of the landscape, highly dependent upon disturbance whether as long-term, large-scale tectonic forces or localized phenomena such as annual or daily flooding and drying, fire, or storm events. Without tectonic or hydrologic disturbance, wetlands gradually progress through a succession of stages to relatively dry upland-type ecosystems. On a large scale, extensive wetlands resulted from recent glaciation, mountain-building, and changes in sea level that interrupted or destroyed drainage patterns. The productivity of many wetlands far exceeds that of the most fertile farm fields. Wetlands receive, hold, and recycle nutrients continually washed from upland regions. These nutrients support an abundance of macro- and microscopic vegetation, which converts inorganic chemicals into the organic materials required - directly or indirectly - as food for animals, including man.
