Northern Orange Free State Research Articles

The grassland communities of the midslopes in the northern Orange Free State, South Africa

A phytosociological and synecologicai analysis of the vegetation of the midslopes of the Heilbron–Lindley–Warden–Villiers area, northern Orange Free State, South Africa, is presented. Releves were compiled in 63 stratified random sample plots. A T winspan classification, refined by Braun-Blanquet procedures, revealed eight plant communities. All communities could be related to specific environmental conditions. A hierarchical classification and phytosociological description of the plant communities are presented. ’n Fitososiologiese en sinekologiese analise van die plantegroei van die middelhange in die Heilbron–Lindley–Warden–Villiers gebied, noordelike Oranje-Vrystaat, Suid-Afrika, word aangebied. Releves is in 63 gestratifiseerde, ewekansig gekose monsterpersele saamgestel. ’n T winspan -klassifikasie, verfyn deur Braun-Blanquet-tegnieke, het agt piantgemeenskappe aangetoon. Alle plantgemeenskappe is geassosieer met spesifieke omgewingstoestande. ’n Hierargiese klassifikasie en fitososiologiese beskrywing van die plantgemeenskappeword aangebied.

The grassland communities of the footslopes in the northern Orange Free State, South Africa

The grassland communities of the footslopes in the northern Orange Free State, South Africa

Low thicket communities of rocky outcrops in the northern Orange Free State

A phytosociological analysis of the low thicket vegetation of the rocky outcrops of the Heilbron–Lindley–Warden–Villiers area (northern Orange Free State) was conducted. Releves were compiled in 67 stratified random sample plots. A T winspan classification, refined by Braun-Blanquet procedures, revealed eight distinct plant communities. A hierarchical classification, description, plant-ecological interpretation and ordination of the plant communities are presented.

Grassland communities of rocky outcrops in the northern Orange Free State

An analysis of the grassland vegetation of the rocky outcrops of the Heilbron–Lindley–Warden–Villiers area, northern Orange Free State, is presented. Releves were compiled in 42 stratified random sample plots. A T winspan classification, refined by Braun-Blanquet procedures, revealed four plant communities. This was confirmed by the ordination of the plant communities. All communities could be related to specific environmental conditions. A hierarchical classification and phytosociological description of the plant communities are presented.

The physical environment and major plant communities of the Heilbron–Lindley–Warden–Villiers area, northern Orange Free State

An analysis of the physical environment and associated major plant communities of the Heilbron–Lindley–Warden–Villiers area (northern Orange Free State) is presented. Releves were compiled in 263 stratified random sample plots. Care was taken to avoid severely degraded areas. A T winspan classification, refined by Braun-Blanquet procedures, revealed three distinct vegetation types. These vegetation types were subdivided into seven major plant communities. A hierarchical classification, description and ecological interpretation of the seven major plant communities are presented. The easily distinguishable major plant communities should be managed as separate ecological units in order to achieve optimal utilization and conservation of the vegetation of this part of the Grassland Biome.

Plant communities of the rocky outcrops of the northern Orange Free State, South Africa

An analysis of the plant communities of the rocky outcrops of the northern Orange Free State is presented. Releves were compiled in 42 stratified random sample plots. Care was taken to sample vegetation which is representative of vegetation in pristine condition whenever possible. A TWINSPAN classification, refined by Braun-Blanquet procedures, revealed seven distinctive plant communities. A hierarchical classification, description and ecological interpretation of the plant communities are presented. One order, three alliances, six associations and two sub-associations are newly described. The restricted distribution of the plant communities, together with the species richness and high species diversity recorded within these communities, makes it imperative that the conservation of these plant communities receives high priority.

The physical environment and major plant communities of the Vredefort–Kroonstad–Lindley–Heilbron area, northern Orange Free State

An analysis of the physical environment and associated major plant communities in the study area is presented. Releves were compiled in 183 stratified random sample plots. Care was taken to avoid severely degraded areas. A T winspan classification, refined by Braun-Blanquet procedures, revealed three distinct vegetation types. These vegetation types were subdivided into five major plant communities. A hierarchical classification, description and ecological interpretation of the five plant communities are presented. The easily distinguishable major plant communities must be managed as separate ecological units in order to achieve optimal utilization and conservation of the vegetation of this part of the Grassland Biome.

The hydrophilic vegetation of the Vredefort – Kroonstad – Lindley – Heilbron area, northern Orange Free State

An analysis of the plant communities of the watercourses of the Vredefort – Kroonstad – Lindley – Heilbron area (northern Orange Free State) is presented. Relevés were compiled in 34 stratified random sample plots. A T winspan classification, refined by Braun-Blanquet procedures, revealed four distinct plant communities. A hierarchical classification, description and ecological interpretation of the plant communities are presented. ’n Analise van die plantgemeenskappe van die waterbane van die Vredefort – Kroonstad – Lindley – Heilbron area (noordelike Oranje-Vrystaat) word gegee. Relevés is in 34 gestratifiseerde ewekansig gekose monsterpersele saamgestel. ’n T winspan -klassifikasie, verfyn deur Braun-Blanquet-prosedures, toon vier duidelik onderskeibare plantgemeenskappe. ’n Hiërargiese klassifikasie, beskrywing en ekologiese interpretasie van hierdie plantgemeenskappe word aangebied.

The plant communities of the undulating grassland of the Vredefort – Kroonstad – Lindley – Heilbron area, northern Orange Free State

An analysis of the plant communities of the undulating grasslands of the northern Orange Free State is presented. Releves were compiled in 107 stratified random sample plots. Care was taken to avoid sampling of severely degraded areas. A T winspan classification, refined by Braun-Blanquet procedures, revealed six distinct plant communities. A hierarchical classification, description and ecological interpretation of the plant communities are presented.

Brief Historical Review of Membrane Development and Membrane Applications in Wastewater Treatment in Southern Africa

Away back in 1953 few people in the world, let alone South Africa, knew or had heard about membrane desalination, but there was an increasing awareness that electrodialysis had considerable potential for the desalination of brackish water. In South Africa the development of the new gold fields in the northern Orange Free State and the problems posed by the presence of excessive volumes of very saline mine waters stimulated interest in desalination and the CSIR* in collaboration with the mining industry became involved in the development of the electrodialysis process. By 1959 the largest brackish desalination plant in the world had been built and commissioned. South Africans were thus in the forefront of this technology, even to the extent of making the required membranes locally. Our historical review of membrane development and the applications of membrane technology in Southern Africa encompasses both pressure- and voltage-driven processes. Examples of the pressure processes are microfiltration, ultrafiltration and charged membrane ultrafiltration or nanofiltration, and finally reverse osmosis with fixed and dynamically formed membranes. The voltage-drive processes considered are electrodialysis and electrodialysis reversal.

Analysis of viverrid scats from the northern Orange Free State

Analysis of viverrid scats from the northern Orange Free State

Plague in South Africa: a study of the epizootic cycle in gerbils (Tatera brantsi) in the northern Orange Free State.

1. The course of an epizootic of plague in thirty-four colonies of gerbils (Tatera brantsi) was observed by counting, at 4-weekly intervals, the number of burrows which, when they had been closed on one day, were found open on the next. One gerbil could open an average of eight burrows in one night.2. Regular censuses on the twenty-one colonies which survived until the last phase of the epizootic showed that the gerbil population fell from about 420 at the end of June 1940 to none at the end of January 1941. From May 1941 to August 1942, 3-monthly counts revealed some recolonization, but field officers reported that between 1942 and 1951 the gerbils sometimes died from plague, and the population never regained its former level.3. During 1940, two to four colonies died out every 4 weeks. The time of year seemed not to influence the course of the epizootic.4. Pasteurella pestis was detected in some gerbil colonies 4–6 months before they died out.5. Plague-infected gerbil fleas were found which had been immured in blocked deserted burrows for periods of up to 120 days.6. The passage of infection was traced from the reservoir in gerbils to other wild rodents (Otomys irroratus, Rattus (Mastomys) natalensis), to house rats (Rattus rattus) and to man.