Vegetation ecology of the pans (playas) of Soetdoring Nature Reserve, Free State Province

Abstract

A comparison of the vegetation of two pans (playas) inside Soetdoring Nature Reserve, a freshwater and a brackish pan, is presented. These ephemeral pan communities are also compared to the vegetation of the hot spring and two permanently inundated earth dams inside the brackish pan's basin. The vegetation of the freshwater communities differs significantly from that of the brackish pan itself. The freshwater pan was classified as a Mixed Grass Pan and the brackish pan as an Open Diplachne Pan. The Mixed Grass Pan is characterised by a Cynodon transvaalensis – Gnaphalium declinatum community, associated with the following sub- communities: Selago dinteri – Cynodon transvaalensis , Panicum schinzii – Cynodon transvaalensis and Portulaca oleracea – Cynodon dactylon subcommunity. Cynodon transvaalensis is the dominant species in this pan. The Open Diplachne Pan is characterised by a Diplachne fusca – Eragrostis bicolor community with a Diplachne fusca subcommunity and an Eragrostis bicolor – Diplachne fusca subcommunity associated with it. Diplachne fusca is dominant in the pan basin. A TWINSPAN classification, refined by Braun-Blanquet procedures, revealed five distinct plant communities for the pan basins and freshwater areas inside the basin collectively. This information is important since very few published analyses are available for pans in the Free State Province, as well as in South Africa as a whole.