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Classification of Natural Ponds and Lakes
in the Glaciated Prairie Region

Synoptic Outline of the Classification System


The natural ponds and lakes in the glaciated prairie region are represented by a considerable number of combinations of class, subclass (if differentiated), and cover type. A synoptic outline showing some of the more conspicuous plant associations is presented below in a resume of the classification system. While only the more usual characteristic plants are given, it should be recognized that in certain ponds other primary species listed in appendix A may be the prevalent vegetation.

Class I - emphemeral ponds.

Central zone represented by low-prairie vegetation (Poa pratensis, Solidago altissima, etc.).
Subclasses: None
Cover types: 1, 2, 3, and 4.

Class II - temporary ponds.

Central zone represented by wet-meadow vegetation (generally fine-stemmed grasses and sedges with associated forbs).
Subclasses:
A - FreshPoa palustris, Boltonia latisquama, etc.
B - Slightly BrackishHordeum jubatum, Calamagrostis inexpansa, etc.
Cover types: 1, 2, 3, and 4.

Class III - seasonal ponds and lakes.

Central zone represented by shallow-marsh vegetation (moderately coarse grasses and sedges with associated forbs).
Subclasses:
A - FreshCarex atherodes, Glyceria grandis, etc.
B - Slightly BrackishScolochloa festucacea, Eleocharis palustris, etc.
C - Moderately BrackishAlisma gramineum, Beckmannia syzigachne, etc.
Cover types: 1, 2, 3, and 4.

Class IV - semipermanent ponds and lakes.

Central zone represented by deep-marsh vegetation (relatively coarse marsh emergents or associated submerged aquatics).
Subclasses:
A - FreshScirpus heterochaetus, etc.
B - Slightly BrackishTypha spp., Scirpus acutus, etc.
C - Moderately BrackishScirpus acutus, etc.
D - BrackishScirpus paludosus, Scirpus acutus, etc.
E - SubsalineScirpus paludosus, etc.
Cover types: 1, 2, 3, and 4

Class V - permanent ponds and lakes.

Central area represented by permanent-open-water zone (devoid of emergent vegetation, but submerged vegetation, particularly Ruppia occidentalis, often present).
Subclasses (based on species composition of peripheral zones):
B - Slightly BrackishTypha spp., Scolochloa festucacea, etc.
C - Moderately BrackishScirpus acutus, Hordeum jubatum, etc.
D - BrackishScirpus paludosus, Scirpus americanus, etc.
E - SubsalinePuccinellia nuttalliana, Salicornia rubra, etc.
Cover Types: 3 and 4

Class VI - alkali ponds and lakes.

Central area represented by intermittent-alkali zone (devoid of emergent vegetation; Ruppia maritima often common).
Subclasses: None
Cover types: 3 and 4

Class VII - fen ponds.

Central zone represented by fen vegetation (Glyceria striata, Carex aquatilis, etc.).
Subclasses: None
Cover types: 1, 2, and 3.

This classification system was tested repeatedly during intensive field studies in North Dakota and was found to be both expedient and realistic. Observations during exploratory trips through other parts of the glaciated prairie region (including the Prairie Provinces of Canada and States adjoining North Dakota) indicate that it is an effective method for the entire region. In certain local areas, particularly those near the margin of the glaciated prairie region, minor modifications may be required. A number of Federal and State and Provincial agencies in the United States and Canada have also field-tested the classification system. Their findings to date generally support the direct application of this system in their wetland investigations.


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