Dune vegetation and coastal thicket plant communities in threatened limestone fynbos of Andrew’s Field and Tsaba-Tsaba Nature Reserve, Struisbaai, Western Cape

Abstract

The coastal thicket and dune vegetation of Andrew’s Field and Tsaba-Tsaba Nature Reserve was classified using Braun-Blanquet procedures and TWINSPAN. The vegetation was sampled using 74 randomly stratified sample plots. The floristic composition, cover- abundance of each species, and several environmental variables were recorded in each sample plot. Six plant communities were identified, namely, Rhus glauca - Euclea racemosa low to tall closed thicket community; Chrysanthemoides monilifera - Solanum africanum low closed dune shrub community; Chrysanthemoides monilifera - Ehrharta villosa var. maxima low to high closed dune shrub community; Ehrharta villosa var. maxima low to short closed dune grassland community; Ammophila arenaria low to short closed dune grassland community; and Arcthotheca populifolia - Thinopyrum distichum low to short open beach community. These were subdivided into eight subcommunities and four variants. All communities, sub-communities and variants were described and ecologically interpreted. The distribution of the communities, sub-communities and variants can mainly be ascribed to differences in landform, rockiness of the soil surface the degree of protection / exposure of the vegetation to the dominating winds of the area.