Classification and ordination of aquatic macrophytes in the Pongolo River Pans, Natal

Abstract

The physiography, soils and climate are briefly described for the Pongolo River flood plain pans situated in north-east Zululand (27 S, 32 E), Natal, South Africa. Quantitative vegetation data ob­tained from 60 stands distributed over 9 pans were summarized using a Braun-Blanquet procedure and a Principal Components Analysis (PCA). Both approaches indicated that the aquatic vegetation could be subdivided into two main groups of growth forms: the submerged and the floating and/or rooted-floating aquatic plants, each showing a distribution influenced primarily by physical factors such as exposure and depth of water. In the PCA, each of the above groups was defined by two stand noda, each nodum representing a plant community that could be observed in the field. The Braun- Blanquet analysis further subdivided the floating and/or rooted-floating aquatic plants into groups of species on the basis of chemical and substrate factors.