Assessing species richness, diversity and assemblage of forest patches within a grassland matrix in the Afrotemperate ecosystems

Abstract

Changes in species diversity have been widely used in environmental monitoring and global change studies as an indicator of vegetation change over time. High mountain ecosystems such as the Golden Gate Highlands National Park (GGHNP) host a relatively high number of plant species due to less human disturbances compared to the surrounding lowland areas. This study investigated the species richness and diversity in the Afrotemperate forest and woodland communities of the GGHNP. For vegetation classification, the TWINSPAN algorithm was firstly used to do a floristic analysis of thirty-two sampling plots and refined further using the Braun-Blanquet procedures and JUICE programmes. The Detrended Correspondence Analysis (DCA) and the phytosociological analysis of the vegetation data resulted in five plant communities and one sub-community across various topographic gradient. The Olinia emarginata–Podocarpus latifolius forest was found to be the most diverse forest whereas the Kiggelaria africana forest showed relatively lower species diversity. Species richness was also relatively high in the Olinia emarginata–Podocarpus latifolius forest plots, compared to the Leucosidea sericea–Buddleja salviifolia woodland, and the Euclea crispa–Protea caffra–roupelliae savannas. Data on plant assemblages and classification provide invaluable information for studies focussing on climate change, species distribution models and the associated bioclimatic variables. Understanding the importance and complexities of high mountains and forest ecosystems is therefore essential for developing effective conservation strategies.