Floristic composition and diversity in tsitsa river catchment area, the eastern cape province, South Africa

Abstract

Background and Objective: Assessment of vegetation in catchment areas need to be assessed and understood in terms of plant diversity, ecological processes and functions that support appropriate ecosystem goods and services. The aim of this study was to assess plant species composition and diversity within the Tsitsa river catchment area in the Eastern Cape province, South Africa. Materials and Methods: Nineteen square plots measuring 5×5 m were established in Tsitsa river catchment area. Within each plot, environmental data and species present were recorded including Braun-Blanquet cover-abundance values for all species present in the plot. Vegetation and environmental data were analyzed using palaeontological statistics (PAST) version 3.06. Results: In total of 78 plant species were recorded belonging to 24 families and 57 genera. Among the documented species, 11.5% are exotic to South Africa. Plant families with the highest number of species were: Asteraceae with 15 species, followed by Poaceae with 14 species, Cyperaceae (10 species), Fabaceae and Rubiaceae (5 species each), Lobeliaceae (3 species), Acanthaceae, Asphodelaceae, Lamiaceae, Oxalidaceae, Polygalaceae, Scrophulariaceae, Verbenaceae and Vitaceae (2 species each). Six main floristic clusters were identified from the hierarchical cluster analysis (HCA) and detrended correspondence analysis (DCA). Results from canonical correspondence analysis (CCA) revealed that species composition was mainly influenced by calcium, carbon, erosion, magnesium, potassium and the slope of the landscape. Conclusion: The diverse species diversity and composition documented is due to several environmental factors particularly calcium, carbon, erosion, magnesium, potassium and the slope of the landscape.