Impact of lifestock on vegetation and soil nutrients around water points in Highland Savanna rangelands, Namibia
Abstract
Artificial watering points can have significant ecological effects in typically arid and semi-arid rangelands where permanent natural surface water is scarce or absent for provision of livestock farming in dry lands Namibia. The impact of livestock grazing on the vegetation and soil status was studied along a grazing gradient from watering points in the Neudamm high land savannah area, in both large and small livestock management system during wet season. Eight artificial points were selected for the study. A 600 m transect was laid out perpendicular to the direction of the grazing gradient from watering points, more or less into the middle of each of the livestock grazing camps. On each transect of each grazing gradient seven 20 x 20 m sample plots were laid out at interval distances of 0 m, 25 m, 50 m, 100 m, 200 m, 400 m and 600 m from water points and at each sampling distance on the transect a nested design of 1 m2, 5 m2 and 20 m2 plots were used for sampling grasses, shrubs and trees resulting in a total of 56 plots in the experimental unit plots. All shrubs and trees were identified, counted and recorded. Density was presented for individual shrubs and trees per 25 m2, 400 m2 to a hectare and grass percentage cover in 1 m2, respectively. Plant species diversity was calculated for each plot using the Shannon-Wienner diversity index. The results indicated significantly (P 0.05) lower plant densities, species diversity, richness and evenness with close proximity to water points, than further away from the water points. Significant differences (P 0.05) were observed for soil particle size analysis, pH, ECw, OC, CEC, P, K, Mg, Ca, Na and K contents along the gradient from water points. Thus, this study concluded there are differences along grazing gradient possibly due to livestock impact of trampling and grazing on vegetation and soil nutrients. This negatively influences vegetation composition, structure, richness and diversity around water points. However, no significant difference (P 0.05) in the quantized impacts of grazing and trampling were observed on soil nutrients and vegetation properties by livestock in different grazing management systems i.e. large-cattle and small stock-sheep camps
Description
A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Science in Rangeland Resources and Management at the University of Namibia
Keywords
Animal -plant relationships, Animal nutrition research, Grazing Namibia, Range management Namibia