Articles by Author: Stuart J Piketh

Search results for Stuart J Piketh

We found 66 results for you
  1. Bird species richness and densities in relation to sulphur dioxide gradients and environmental variables

    Bird species richness and densities in relation to sulphur dioxide gradients and environmental variables

    Item type: Journal Article • Journal: Ostrich: Journal of African Ornithology
    The expansion of coal-fired power stations in South Africa has resulted in growing environmental concerns as they are the largest emitters of sulphur dioxide (SO2). Sulphur dioxide emissions from power plants pose a potential threat to avian populations. However, the...
  2. Refinement of a model describing forage production, animal production and profitability as a function of bush density in the false thornveld of the eastern cape

    Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa
    An existing model describing the influence of Aeacia karroo density on forage production, animal production and profitability is reviewed and amended to introduce recent research results.
  3. Coevolution of African grasses and large herbivores

    Coevolution of African grasses and large herbivores

    African grasslands have developed under the impact of fire and grazing. There has been strong selection for grass plants to deter, escape and tolerate herbivory, and to escape and tolerate fire. It follows that the complete withdrawal of fire from...
  4. Towards a method of assessing the veld condition of the valley bushveld in the Eastern Cape

    Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa
    Currently, no technique is available for assessing the condition of Valley Bushveld in the Eastern Cape. The objective of this investigation was to develop a method of scoring bushveld according to its productive condition. It was established, through principal component...
  5. Adaptation of a decreaser and an increaser grass species to defoliation in semi‐arid grassveld

    Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa
    Grasses have developed through natural selection to deter, escape and tolerate herbivory, and to escape and tolerate fire. In the semi‐arid grassveld of the Eastern Cape, the species Themeda triandra and Sporobolus fimbriatus have been classified as Decreaser and Increaser...
  6. The influence of an <em>Acacia karroo</em> tree on grass production in its vicinity

    Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa
    The investigation was concerned with the impact of an Acacia karroo tree on the productivity of the surrounding herbaceous layer.
  7. Browse and herbage production in the eastern cape thornveld in response to tree size and defoliation frequency

    Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa
    Grass yields in this semi‐arid savanna declined as the size of Acacia karroo increased. Browse yields, however, did not increase as trees grew out beyond 1,8 m in height and it follows that if bush thinning is required, then the...
  8. The effect of severe drought and management after drought on the mortality and recovery of semi‐arid grassveld

    Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa
    The False Thornveld of the Eastern Cape experienced a particularly intense drought during the 1982/83 growing season. Extensive grass mortality took place during the drought. After the drought, recovery was particularly sensitive to the post‐drought management treatment applied. Veld that...
  9. Water utilization patterns around isolated <em>Acacia karroo</em> trees in the False Thornveld of the eastern Cape

    Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa
    The effect of various vegetation treatments on two soil moisture regimes (i.e. the proportion of the experimental period where the soil had sufficient water for: (a) growth, and (b) to keep the plants turgid in the vicinity of experimentally isolated...
  10. Use of multivariate techniques to identify vegetation units and monitor change on a livestock production system in a semi‐arid savanna of the eastern Cape

    Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa
    Species composition data of the grass layer were determined from point surveys along permanently demarcated transects. These data were separated into vegetation units using multivariate techniques. The repeatability of this classification was tested on data collected over a period of...