3. Electronic Theses and Dissertations (ETDs) - All submissions
Permanent URI for this communityhttps://wiredspace.wits.ac.za/handle/10539/45
Browse
2 results
Search Results
Item Spatio-temporal trends in vegetation dynamics across a savanna-dominated national park(2018) Ernst, Yolandi-MariThe Kruger National Park (KNP) is a savanna-dominated landscape upon which complex processes interact to result in dynamic patterns. Evidently, climate change is already impacting the KNP landscape. A major objective in the KNP’s Strategic Adaptive Management approach (SAM) is therefore to maintain ecological integrity through an informed, objective-driven decision-making process that involves Thresholds of Potential Concern. Continuous and informative monitoring at the landscape-scale is therefore essential, but challenging to do for such dynamic savanna environments, over large spatial extents. To address this concerning issue, I aimed to develop and evaluate a remote sensing-based methodological approach for the assessment and monitoring of landscape-scale spatio-temporal trends in vegetation greenness dynamics in relation to the influence of precipitation, fire and elephants across the Kruger National Park. My approach is novel in its combination of methods to monitor dynamic landscapes over large extents. Chapter 2 comprises of a comparison of different NDVI data products within the framework of mean-variance and spatial persistence analyses, thereby building the foundation upon which I based data analyses in the following chapters. Comparison of NDVI data derived from different satellite sensors revealed that the overall mean-variance trajectories and spatial persistence were relatively similar, but some large variations were evident due to differences in sensor characteristics. In Chapter 3, I exploited the fact that the relationship between phenology and vegetation greenness are confounded by the effect of other drivers. Through subjecting NDVI, phenology metrics and precipitation to spatial persistence analyses and then quantifying the converging and diverging change trends, I was able to show that precipitation is the primary driver of the general spatial greenness trends across the park but that persistent changes in vegetation greenness at finer spatial scales were more likely caused by other factors, such as fire and herbivory during the period of observation. Following this, I evaluated the role of fire and elephants as drivers of vegetation change trends with the use of pheno-season (defined by phenology metrics) vegetation greenness in correlation analyses. Here, the results seemed to suggest a combined association of elephants and fire frequency with vegetation greenness change trends, although the results showed much variability. Elephant bull and herd densities iii also seem to play different roles in their effects on vegetation greenness Through further development and adjustment of data input the proposed monitoring approach could be optimised for the broad-scale monitoring of vegetation pattern and processes within the SAM framework.Item The spatial analysis of the ancient funerary landscape of the Sahara Fazzan - a case study of the Wadi ash-Shati, Libya(2017) Kgosietsile, TshekisoThis study is an initial attempt to investigate the spatial arrangement of graves which are believed that they can shed new light on the mortuary behaviours of ancient societies. The aim of this study is to utilise Geographic Information System (GIS) and remote sensing to document and explore the funerary landscape of the Wadi ash-Shati, Libya using a comprehensive set of environmental variables that might have influenced the spatial distribution of Garamantian funerary monuments. In view of that argument, this study is motivated by these two objectives; documenting all the Garamantian funerary monuments and settlements visible in high resolution satellite imagery and investigating their spatial patterns in their topographic setting. Spatial patterns were achieved by plotting digitised graves data from remotely sensed imagery (accessed through Google Earth) and hand held Global Positioning System (GPS) data in a GIS environment in order to extract patterns and structure in the dataset. In order to better understand these patterns and structures, the following GIS approaches; slope, elevation, visibility, clustering, directional distribution analyses were utilised. The results of the GIS analyses showed that there was correlation between graves location, qsurs or settlements, wells and with the environmental variables (slope, elevation, and distance to water resources). On the basis of the results of this research, it can be concluded that environmental variables were major factor in the placement of graves, qsurs and wells. The placement of these site locations can be related to as an expression of the socio-political, economic, cultural and ideological characteristics of the Garamantian society that created the burials and organised the Wadi ash-Shati landscape. The present study concluded that the Garamantian civilisation had established changes in the landscape that promoted the development of elaborate funerary monuments which peaked significantly during the time when aridity became immense in the study region. However additional research is necessary to provide more conclusive results and interpretations of this study, as such results from the analyses carried out should not be viewed as absolute, but as a stepping ladder for future investigation in the Wadi ash-Shati region. Keywords: GIS, Remote sensing, Funerary Landscape, Wadi ash-Shati, Libya, Spatial Analysis, Garamantian, Google Earth, Global Positioning System (GPS), Environmental Variables