ETD Collection
Permanent URI for this collectionhttps://wiredspace.wits.ac.za/handle/10539/104
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Item The effect of the resolution of topography description on 2-D modelling of river habitat(2018) Kamps, Michael ChristiaanThe main objective of this report is to assess the effect of different topographic (elevation) data sources on river habitat modelling in low flow conditions. In the study, digital terrain models which consists of various datasets were assessed using 2-D hydraulic software models. The representation of the terrain was sourced from the following: airborne laser scanning, total station survey, a smartphone device and a handheld GPS device. From the results, which consisted of 4 simulations (discharges of 1.5 m3/s, 1 m3/s, 0.5 m3/s, and a field measurement of 0.3 m3/s) for each topographic dataset, the water level and velocity were derived and a comparison was made against the most accurate data set (total station survey). The comparisons included how each model was able to describe a habitat in terms of defined biotopes. This research proves that a total station survey is still the most accurate, however with the advancement in GPS technology a handheld GPS device has proven to be adequate for a desktop or intermediate study. In addition, a smartphone’s GPS tends to be more adequate for large surveys and inefficient for habitat modelling.Item A sociological and biological study of human-wildlife interactions(2018) Taylor, EmilyUrbanisation transforms habitat for wild animals and increases their interaction with humans as they compete for space and resources. Encounters between humans and wildlife in the City of Johannesburg Municipality (COJ) often end in conflict, more so with species that may be feared or disliked. To improve the nature of interactions between wildlife and people, it is important to understand where wildlife occurs, what kinds of conflicts it is involved in and where, and people’s common motivations for how they engage with wildlife. This study aimed to provide a biological and a sociological investigation into the nature and causes of human-wildlife conflict in the City of Johannesburg. I conducted analyses of wildlife sightings reports from a number of different sources, to develop a better understanding of the distribution of wildlife in the municipality, and to determine whether locations of reports were influenced by factors such as land-cover class, proximity to green spaces, or human population density. I conducted similar analyses on reports of human-wildlife conflict incidents to determine whether reported incidents were influenced by the aforementioned factors, as well as by the number of presence records for these locations. I also intended to determine what common types of conflict occurred and where. Spatial analysis of available presence and conflict data suggested that both wildlife presence and conflict incidents were more commonly reported in regions in which certain land-cover classes, such as residential areas with dense trees, are prevalent, and within 1 km of green spaces. To investigate potential underlying socio-demographic influences of human behaviour towards urban wildlife, I conducted surveys of 416 adolescents from three schools in different areas of Johannesburg, and 779 adult urban residents. The surveys were adapted from existing scales and designed to ascertain levels of basic knowledge about wildlife, general attitudes towards wildlife, the types of behaviour respondents are likely to show when encountering wildlife, and ultimately to reveal relationships between these measures. I found that respondents’ attitudes towards wildlife were significantly influenced by the extent of their knowledge, however knowledge was shown to have developed as a result of more than just formal education received. I also found that predicted behaviour towards wildlife was predominantly affected by both knowledge levels and attitudes. Demographic variables such as age and gender did influence all three measures but culture was the most significant demographic predictor of knowledge, attitude, and behaviour. These findings provide an indication that human-wildlife interactions can be effectively improved through developing people’s knowledge. However this must be addressed through both formal education and informal cultural teachings to have significant impact, particularly for interactions with animals that have deeply ingrained negative cultural associations, such as owls and bats.Item Disturbance and habitat factors in a small reserve : home range establishment by black rhinocerous (diceros bicornis minor)(2012-01-18) Odendaal, KarenBlack rhinos are being moved to small protected areas in an attempt to expand their range; and factors commonly found within these small protected areas could influence black rhino ecology. From the literature we understand how biological factors affect rhino resource selection but not in the context of small reserves. This study investigates the home range establishment of black rhinos and those factors commonly associated with small reserves that affect rhino habitat-use as well as weigh the relative importance of each of them. The factors considered were human disturbances such as residences, lodges, roads and fences, slope, elevation, perennial water, burnt areas and vegetation type. Minimum convex polygon, 50% core and 95% local convex hull (LoCoH) was used to generate home ranges from sightings data collected for 17 individuals. The mean 95% LoCoH home range was 3.77 km² (95% CI: 2.92- 4.63, n=17), and is comparatively small in relation to the adaptive kernel home ranges of previous studies. A use-availability resource selection function showed that black rhinos avoided areas close to residences, lodges, camps, and perennial water, and these variables played a bigger role than their selection for thicket vegetation. These factors have a highly significant effect on rhino resource selection, and this effect is magnified due to the density of human disturbances and water points commonly found in small reserves. It is essential that this knowledge be applied in the management of reserves protecting black rhinos.Item Do zebra (Equus quagga) select for greener grass within the foraging area?(2012-01-17) Boyers, MelindaSpatial patterns in topography and forage distribution clearly determine large herbivore movements but our understanding of the foraging strategies that free-grazing herbivores adopt at different temporal and spatial scales is limited. Different foraging response patterns are displayed at different scales. Here fine-scale foraging strategies of Zebra (Equus quagga) were investigated by studying their selection for vegetation greenness in a Southern African savanna. Zebras have high-energy requirements thus the primary productivity and condition of the habitat plays an important role on their movements. Grass greenness was measured by Normalized Difference Vegetation Index (NDVI), a proxy for vegetation productivity and quality. Finer-scale studies are needed to understand the processes leading to a correlation between NDVI and herbivores performance. Data was collected at two different spatial scales, foraging area and feeding station. Food selection was recorded in relation to grass species and grass tuft greenness. Within the foraging area, grass species and greenness within zebra feeding stations were compared with random non used stations. Within the feeding station, species and greenness of grasses eaten by zebra were compared with those of grasses available but not eaten. Zebra selection was not consistent across scales. Although greenness was a factor in selection at feeding station levels and grass tuft levels; feeding station selection was limited to greenness due to season, and selection for species occurred only at the grass tuft level. However, zebra did select for the greener grass tufts within the feeding station even if it meant to eat ‘less palatable’ species (i.e. Eragrostis rigidior) instead of ‘very palatable’ species (i.e. Panicum maximum).