A new classification system evolved in 1974 as a preliminary to the more extensive current national wetlands inventory. The new system classifies wetlands into systems, subsystems, classes and subclasses. Classification enables scientists to analyze data more efficiently and to better predict the effects of intentionally changing a wetland. Some wetlands constantly fluctuate from wet environments to dry and back again. This cycle may take days, months or even years depending on the climate.
Plants flourish, then die, and wildlife species migrate in and out as the habitat changes.
Since wetland characteristics change, some wetlands may actually fall into several different classifications over a period of only a few years. Water levels of other wetlands may not fluctuate to such an extreme. They may, however, vary enough to influence the type of vegetation and, possibly, the species of wildlife present. As a result, relying on the type of vegetation and the level of the water to distinguish between classifications can be confusing. On the other hand, the permanence of soil characteristics can be a disadvantage.