The vegetation ecology of the Seringveld Conservancy, Cullinan, South Africa

Abstract

The Seringveld Conservancy is situated near Cullinan in an area is that is characterised by deep sandy soils. Sand mining for the building industry has become a major threat to the biodiversity of the area. The flora of the Conservancy is best described as a gradual ecotone between the grassland and savanna biomes. The fist objective of the study is to describe the vegetation of the Seringveld Conservancy, in terms of plant communities, plant species composition, habitat as well as composing a vegetation map of the area. The second objective of the study is more theoretical and is aimed at providing a definition for savannas as well as shedding light on the complexity of South African savannas and there underlying driving forces. The Braun-Blanquet approach was used for sampling and 125 relevés were compiled. The data was captured using TURBOVEG and data analysis followed in JUICE 7.0. A total of 376 species was recorded in the area. Analysis from JUICE resulted in a TWINSPAN dendogram, synoptic table and two phytosociological tables. The phytosociological tables obtained from JUICE were refined using Braun-Blanquet procedures. Ten main plant communities and two sub-communities were identified. Each plant community was described in terms of species composition, dominant species and diagnostic species, and ecologically interpreted in terms of habitat characteristics. The plant communities were also compared to communities found in other studies in close proximity of the Seringveld i.e. Ezemvelo Nature Reserve. ArcGIS was used to create various maps further highlighting the uniqueness of the area. A vegetation map indicating the distribution of the plant communities was compiled. The combined results of the phytosociological tables as well as the GIS maps indicate that the Seringveld Conservancy is a complex area containing high biodiversity. Trying to define savanna is related to scale. The study area is considered to be savanna at local scale, this study will refer to savanna as a vegetation type with a well developed grassy layer and an upper layer of woody plants, which can vary from widely spaced to 75 percent tree cover. There is a gradient present between equilibrium and non-equilibrium dynamics in savanna ecosystems of southern Africa.