Influence of habitat differences on the ecological grouping of grass species on a grazing gradient.

The ecological grouping (Decreaser and Increaser groups) of individual species was determined on two topographical units in the Highland Sourveld of the Orange Free State. For this purpose gradients were selected, giving special attention to fence-line comparisons, vegetation at different distances from watering points and ungrazed vegetation. The ecological grouping (Decreaser and Increaser groups) of species on a grazing gradient differed not only for different topographical units, but also for sub-habitats within a certain unit. Broad standardized groupings of species into Decreaser and Increaser groups are therefore scientifically wrong and of little practical use.Keywords: botany; decreaser species; ecotypes; grazing gradient; highland sourveld; increaser species; orange free state; ordination; south africa; subhabitat; subhabitats; units; watering point

Ecological status of species on grazing gradients on the shallow soils of the western grassland biome in South Africa.

Grasses on the shallow soils of the western grassland biome of South Africa were classified on their ecological status on the basis of their reaction to grazing. Vegetation data were gathered in such a way that those of different successional stages could be identified. An ordination technique was used to define the grazing gradient. Species abundance curves were statistically fitted to the grazing gradient and used to classify the species into decreaser and increaser categories.Keywords: bc land type; degradation; ecological status; grasses; grassland; grassland biome; grazing; grazing gradients; ordination; south africa; species abundance; succession; technique; veld condition assessment; western transvaa

The impact of fertilization veld in terms of species composition and basal cover of grazed veld in the Potchefstroom area.

The impact of fertilization on veld in the Potchefstroom area was investigated. Nitrogen and phosphorus were applied annually from 1972/73 until 1981/82. The control plots and the fertilized plots were grazed with year-old steers. Species composition and basal cover were recorded using the wheelpoint technique. The results clearly indicated the formation of a soil fertility gradient as a result of the fertilization. Although there was a decrease in the ecological status of the fertilized plots, the production and palatability of the sward increased and thus also animal performance.Keywords: animal performance; basal cover; botany; composition; cover; ecological status; fertility; fertilization; nitrogen; palatability; performance; phosphorus; potchefstroom; production; retrogression; soil; soil fertility; south africa; species composition; succession; technique; vel

Identification and selection of benchmark sites on litholitic soils of the western grassland biome of South Africa.

An approach to identify benchmarks for different ecological situations in the grassland biome is described. The approach is illustrated by using information on vegetation change, role of habitat factors and the relative palatability differences between the species of the vegetation on shallow soils of the litholitic complexes in the western parts of the grassland biome. The information was obtained from the ordination and interpretation of vegetation and habitat data gathered at different distances from watering points and in vegetation under different grazing pressures.Language: EnglishKeywords: benchmarks; Ecological situations; grassland; grassland biome; grazing; grazing pressure; habitat; habitat factors; ordination; palatability; soils; south africa; succession; vegetation; vegetation change; veld condition; Veld conditions; watering points; Western Grassland Biom