Vegetation ecology of the Southern Free State

Abstract

English: This study forms an integral part of the main long-term goal to compile a . comprehensive synecological synthesis of the vegetation of the southern Free State. (1) to identify, classify and ecologically interpret the plant communities in the study area, (2) to compile a comprehensive phytosociologicaJ and synecological synthesis of the vegetation of the study area, including all the phytosociological data compiled by other researchers in the southern Free State, and (3) to take part in compiling a comprehensive synecological synthesis of the Grassland Biome. Relatively little is known about the vegetation of the study area. The main aim of the study was: The study area is situated in the southern Free State, covers approximately 27 000 km² and is bounded by latitude 29° South andlongitude 270 East. It is bounded by the Orange River in the south and by the imaginary boundary between the Free State and Northern Cape Province in the west. The aims were achieved through compiling extensive phytosociological surveys in the study area. The study area was stratified into relative homogeneous units of major attributes such as geology, topography (land form), physiognomy and dominant species. A phytosociological survey according to Braun-Blanquet procedures as weU as habitat analysis were being done. Data were being classified through the TWINSPAN program and then refined by Braun-Blanquet procedures. From the 2 370 relevés compiled in the southern Free State, 394 plant communities were identified, classified and ecologically interpreted. 16 Major vegetation units were described from the 394 described plant communities. An ordination algorithm (DECORANA) was used to indicate the floristic relationships among the vegetation units and make the classifications more interpretable. The synecological synthesis of the vegetation of the southern Free State plays an important role in compiling a comprehensive synecological and syntaxonomical synthesis of the vegetation of the Grassland Biome of southern Africa.

Afrikaans:Hierdie studie vorm 'n integrale deel van die oorhoofse langtermyn doeI om 'n omvattende sinekologiese sintese van die Grasveldbioom van suidelike Afrika daar te stel. Met die aanvang van die projek was daar relatief min inligting oor die plantegroei van die gebied bekend. Die hoofdoel van hierdie studie was: (1) om die plantgemeenskappe in die studiegebied te identifiseer, te klassifiseer en ekologies te interpreteer, (2) om 'n omvattende fitososiologiese en sinekologiese sintese van die plantegroei van die studiegebied daar te stel, insluitende alle fitososiologiese data ingesamel deur ander navorsers in die suidelike Vrystaat, en (3) om 'n bydrae te lewer omtrent die daarstelling van 'n volledige sinekologiese sintese van die Grasveldbioom. Die studiegebied Is in die suidelike Vrystaat geleë, beslaan 'n totale oppervlak.te van ongeveer 27 000 km² en word begrens deur die lengtegraad 29°Suid en breedtegraad 27°00s. Dit word begrens deur die Oranjerivier in die suide en die denkbeeldige grens tussen die Vrystaat- en Noord-Kaap Provinsie in die weste. Die doelwitte is bereik deur ekstensiewe fitososiologiese opnames in die studiegebied uit te voer. Die studiegebied is gestratifiseer volgens relatiewe homogene eenhede van faktore soos geologie, topografie (terrein vorm), fisionomie en dominante spesies. 'n Fitososiologiese ondersoek, volgens Braun-Blanquet prosedures asook 'n habitat opname is uitgevoer. Die data is deur middel van die TWINSPAN- program geklassifiseer en daarna deur die Braun-Blanquet prosedures verfyn. Uit die 2 370 relevés wat in die suidelike Vrystaat saamgestel is, is 394 plantgemeenskappe ge·(jentifiseer,. geklassifiseer, beskryf en ekologies genterpreteer.Uit die omvattende fitososiologiese sintese van die 394 beskryfde plantgemeenskappe van die suidelike Vrystaat is 16 hoofplantegroeitipes in die studiegebied beskryf. 'n Ordeningsalgoritme (DECORANA) wat die floristiese verwantskappe tussen die plantegroei-eenhede aandui, is gebruik om die klassifikasies aan te vul. Die sinekologiese sintese van die suidelike Vrystaat lewer 'n bydra tot die uiteindelike doel, nl. om 'n volledige sinekologiese en sintaksonomiese sintese van die Grasveldbioom in suidelike Afrika daar te stel.