Northern Prairie Wildlife Research Center
| Subclass A- | fresh |
| Subclass B- | slightly brackish |
| Subclass C- | moderately brackish |
| Subclass D- | brackish |
| Subclass E- | subsaline |
Normal and extreme ranges in specific conductance (micromhos/cm³) of surface water in plant communities that characterize these varying degrees of salinity are shown in the section on Plant Species Composition and Differences in Salinity of Surface Water.
Subclasses represented (prevalent subclasses in bold face) in the four major classes referred to are as follows:
| Subclass | ||
| Class II- | temporary ponds | A, B |
| Class III- | seasonal ponds and lakes | A, B, C |
| Class IV- | semipermanent ponds and lakes | A, B, C, D, E |
| Class V- | permanent ponds and lakes | B, C, D, E |
Plant communities of each subclass differ with respect to occurrence or abundance of various plant species. The principal species in each subclass for temporary (Class II), seasonal (Class III), semipermanent (Class IV), and permanent (Class V) ponds and lakes are listed in appendix A. Subclasses are also indicated for many of the illustrations of major classes of wetlands (plates 2 to 26).
Recognition of subclasses requires a visual appraisal of the abundance of various wetland plants, especially primary emergent species in the wet-meadow, shallow-marsh, and deep-marsh zones. The prevalent species of these zones in a particular pond or lake may be compared with the principal species listed under each subclass for the zones being considered. A subclass designation can then be assigned on the basis of similarity.
U.S. Department of the Interior |
U.S. Geological Survey
URL: http://www.npwrc.usgs.gov/resource/wetlands/pondlake/subclass.htm
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