The effects of burning on soil properties and landscape function were investigated in a long-term experiment comparing different burning strategies in a moist montane grassland. Total C, total N, total S, bulk density, plant-available nutrients, and soil acidity were determined in the top 200mm of soil, together with vegetation basal cover at the soil surface. The no-burn treatment had the lowest basal cover (14.8%). Basal cover for the burnt treatments ranged from 19.0% (five-year spring burn) to 25.4% (alternate autumn/spring, burnt every 18 months). The organic matter content of these soils was very high with total carbon ranging from 114g kg -1 in the 0-50mm layer to 77g kg -1 in the 150-200mm layer. Bulk density was very low, being 0.57g ml -1 in the 0-50mm layer. There were no significant effects of burning on the quantity of soil organic matter. The C:N ratio was significantly affected throughout the top 200mm by burning treatments; in the 0-50mm layer it ranged from 14.43 in the no-burn treatment to 16.14 in the treatment burnt every 18 months. Higher C:N ratios in frequently burnt treatments suggests that grassland productivity is N-limited in these treatments. In the top 50mm, soil pH is lower in treatments burnt infrequently (5 year and no burn) than in those burnt frequently, whereas concentrations of basic exchangeable cations (K, Ca and Mg) were lower in treatments burnt infrequently (five-year and no burn) than in those burnt frequently. The higher pH and concentrations of basic cations in frequently burnt treatments wasprobably due to greater cycling of nutrients to the soil surface as a result of higher productivity and deposition of nutrients in ash, together with reduced leaching of cations with nitrate. Landscape Function Analysis was used to measure the functioning of the landscape in terms of scarce resources and the processes that maintain these resources. All sites were highly functional, irrespective of the burning treatment applied. The infrequently burned sites had significantly higher nutrient cycling and infiltration indices than frequently burnt sites and these indices were correlated well with soil chemical properties (acidity, acid saturation, Ca, Cu, K, Mg, P and pH). No significant differences were found between treatments for the stability index.

Commercial livestock production offers one of the main opportunities for mainstreaming of biodiversity conservation in the grassland biome of South Africa. Grazing management is expected to influence success. With the uses of three long-term grazing trials, effects of stocking rate and cattle-to-sheep ratio on the plant composition and diversity of Highland Sourveld grassland in KwaZulu-Natal were examined. Plant diversity was sampled with the use of modified Whittaker plots. Canonical correspondence analysis was used to test the effects of treatments on compositional variation, and general linear models were used to test individual species' responses. In a biennial rotation, burned/grazed plots supported lower species richness of forbs and all plants than unburned/ungrazed plots, attributed to the impact of grazing during the season of occupation. A high stocking rate resulted in a long-term decrease of forb richness in one experiment, but an increase in another. An increasing proportion of sheep to cattle resulted in a long-term decrease of the richness of forbs and of total species richness. The three trials identified nongrass species that behaved as increasers or decreasers in response to an increase in stocking rate, and a set of species that behaved as decreasers in response to an increasing proportion of sheep to cattle. Constraints on using long-term trials for identifying the effects of livestock management on plant diversity include lack of baseline data, limited replication, preexperimental impacts on the study site, and the difficulty of assessing uncommon species. Resumen La producción ganadera comercial ofrece una de las principales oportunidades para canalizar la conservación de la biodiversidad en los pastizales de Sudáfrica. Se espera que el manejo del pastoreo influya en tener éxito. Con este fin, se evaluó el uso de tres ensayos de pastoreo a largo plazo, el efecto de la carga animal y la relación de ganado-ovejas en la composición y diversidad de los pastizales en Highland Sourveld grassland KwaZulu-en Natal. La diversidad de plantas fue muestreada utilizando la te´cnica modificada de las parcelas de Whittaker. Análisis de correspondencia canónica fueron utilizados para probar los efectos de los tratamientos sobre la variación de la composición, y los modelos lineares generales fueron usados para probar la respuesta individual de las especies. En una rotación bienal las parcelas quemadas/pastoreadas presentaron el menor número de especies de herbáceas y de todo tipo de plantas, comparadas con las parcelas sin quema y/o pastoreo. Esto se atribuyó al impacto de la actividad de pastoreo durante la época en que se llevó a cabo. Una mayor carga animal dio como resultado una disminución a largo plazo de la riqueza de herbáceas en un experimento pero se incrementó en otro. Al incrementarse la proporción de ovejas sobre el ganado hubo una disminución a largo plazo sobre el número de herbáceas, así como una disminución en el número total. Durante los tres estudios se identificaron especies no gramínea...

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The balance of papers in this Special Issue show that how Holistic Planned Grazing™ is managed and where it is used impacts the efficacy of the approach. While we will do well to develop more mechanistic models that can identify these thresholds and test them in real-life situations, it is certain that broad generalisations will not do. We can neither dismiss Holistic Planned Grazing out of hand nor claim that it will work anywhere. Both land-users and scientists should consider the evidence at hand along with their management goals (production, conservation or restoration) before deciding what livestock management approach is appropriate.

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