With the development of digital technology during the last decade and the improvement of Geographic Information Systems (GIS), it has become easier for various scientific fields to predict and extrapolate data. Various organisations and institutions continuously develop algorithms and software to assist with specific challenges in multiple fields of science. These technologies and principles have also been effectively applied in the soil science field of pedology. Traditional soil mapping, although effective, is time consuming, arduous and expensive. It is thus important to develop methods whereby the soil forms of an area can be identified faster while providing accurate information to the reader/ user. Conservation areas, such as Phinda Private Game Reserve (Phinda), which covers a large area (greater than 28 000 ha) can benefit from a soil map. The importance of a proper soil map has a great many uses in conservation, but not every organisation or individual can afford it. This is where digital soil mapping (DSM) or Predictive Soil Mapping (PSM) comes into its own. Substantial research and development have been done in the form of methodology and software systems for DSM although it has not been effectively applied to conservation management. By applying these techniques, accurate and interactive soil maps were developed without the burdensome expenses or dangers associated with traditional soil observations in a conservation area. The application of DSM and the use of the soil land inference model (SoLIM) at Phinda resulted in maps based on the Fey soil-form classification as well as a soil sensitivity index (SSI). The SSI was developed based on the various soil forms present at Phinda and the factors that determine its sensitivity to various types of degradation. These digital maps indicated accuracies of 71% (Fey classification) and 72% for the SSI. The kappa values indicated a substantial agreement (0.63) for the Fey classification map and a moderate agreement (0.57) for the SSI map. The SSI was then combined with the predator sightings and the location of infrastructure and commercial lodges to derive the agreement of activities, game drives, which includes off-road driving (ORD) on sensitive soils. As erosion is a concerning problem, predominantly caused by human activities within Phinda, it was necessary to use the SSI map as a base of comparison. This digitally produced soil map will be presented to the conservation management at Phinda whereby planning can be conducted, literally, from the ground up. Proper planning will thus prevent a loss of soil and consequently a loss of biodiversity. All the information was then combined to developed recommendations for Phinda as to improve the overall road network by upgrading, removing and rehabilitating certain roads and provide advice concerning ORD. These decisions, in turn, prevent long-term soil and biodiversity loss while still providing clients with a true African bush experience. / College of Agriculture and Environmental Sciences

Elements of an individuals occupational exposure, such as their posture can affect their comfort during work, and also their long term musculoskeletal health. Knowledge as to the extent of the influence of particular aspects of the exposures can help in providing guidance on risk evaluation, and direct future technical design focus. In many situations the exposures interact, and even if the effects of individual exposures are understood, the interactions are often less so. This is certainly the case with off-road driving exposures. Specific investigations have focussed on the effects of vibration exposure, resulting in the development of international standards and guidelines on measurement and evaluation of exposure. Consideration of the posture of the operator can be accomplished through postural assessment tools, although none of the currently available methods are developed specifically for use within a vehicle environment. The issues of both the posture of the operator and the seated vibration exposure are particularly apparent in off-road agricultural driving environments, where the driving task dictates that operator is often required to maintain specific postures whilst also exposed to whole-body vibration. In agriculture, many of the tasks require the operator to maintain axially rotated postures to complete the task effectively. The analysis of the combined effects of the axial rotation of the operator and the whole-body vibration exposure has been limited to a few studies within the literature, and is currently poorly understood. The overall aim of the thesis was to assess the influence of axial rotation and whole-body vibration on the musculoskeletal discomfort of the neck and trunk, in order that the true extent of the exposure risk may be evaluated. A field study was conducted to determine the common characteristics of some typical exposures, to provide a basis for the laboratory studies. A survey of expert opinion was conducted, examining the knowledge and experience of experts in assessing the relative influence of axial rotation and whole-body vibration on operators musculoskeletal health. The main investigations of the thesis are focussed in the laboratory, where the objective and subjective effects of axial rotation (static and dynamic) and whole-body vibration were investigated. Objective measures included the investigation of muscular fatigue in response to exposures. The tasks investigated in the field study indicated that the exposures often exceed the EU Physical Agents Exposure Limit Value, and that the axial rotation is a large component of the postures required. The survey of expert opinion concluded that combined exposure to axial rotation and whole-body vibration would increase the risks of lower back pain, and that acknowledgement of combined exposures should be included when assessing for risk. The results of the laboratory studies indicated that the greatest discomfort was present when subjects were exposed to axial rotation in the neck and shoulders. Out of the 8 muscles investigated, at most 6 of the 8 indicated fatigue during an experimental exposure. The muscle group which was affected most by the exposures was the m. trapezius pars decendens. Findings demonstrated that when subjects were exposed to axial rotation and whole-body vibration they indicated discomfort and their muscles fatigued. However, there was poor correlation between the sites of discomfort and the location of muscular fatigue. The discomfort findings suggest that there is an increased risk of discomfort from experiencing axial rotation together with whole-body vibration. Investigations of muscular fatigue do not substantiate this finding.

Eco-tourism activities specifically, sometimes have very negative environmental impacts. One such activity which has been observed to have severe negative impacts is driving in dirt tracks (ungravelled natural soil) by game drive vehicles in private game reserves and some National Parks (Nortjé 2005; Laker 2009). It has also been observed that the severity of the impacts and the resilience (recovery potential) of the affected areas differ widely between different areas. It is strongly linked to the properties and qualities of different soils. This study has shown that off-road driving (ORD) has the same effects, and to a greater extent, if it is not well managed and judiciously controlled. Wild animals tend to concentrate in areas with the most nutritious en most palatable vegetation. Consequently these are also the areas where predators, e.g. lion, leopard and cheetah are most likely to be found. It can be expected that these will be the areas with the highest frequencies of ORD in order to get close to these animals. In many landscapes these are the areas which are the most vulnerable to negative impacts by actions like ORD and have the lowest resilience. It has also been observed during game drives and personal communications at several occasions that there is tremendous ignorance amongst tourists regarding the negative environmental impacts of certain activities. This study proved that ORD have strong negative impacts on vegetation recovery, soil resilience and root density distribution through soil crusting and sub-soil compaction. An important finding is that these negative impacts are during both dry and wet soil conditions. Game drive vehicles driving off-road damages the surface soil structure, which lead to soil crust formation and sub-surface compaction. A highly significant result is that most crusting and sub-soil compaction occurred during the first pass of the game drive vehicle, irrespective of the soil type and tyre pressure, thus rewriting the current guidelines for ORD of the South African National Parks, SANParks. Furthermore, results of this study indicated that a significant area in the flood plains of the Makuleke Contractual Park is impacted by ORD. The impacts are serious if one looks at the amount of land that an ORD vehicle can disturb. One of the recommendations would thus be to drive in the same tracks when driving off-road, and lower the tyre pressures. Driving in the same tracks is known as "controlled-traffic" in the agricultural industry. Controlled traffic is very important to minimize compaction. Driving in the same University of Pretoria etd Nortjé, G.P. (2013) tracks during off-road incidents does not significantly affect the degree of compaction under the tracks, but greatly reduces the compacted area. Further results indicated a strong lateral effect of the vehicle tracks, in most cases the whole area between the two tyre tracks as well as up to a distance outside of the vehicle tracks, thus increasing the total area disturbed by ORD. Comparing these vehicle impacts with animal path resulted in some important findings. Animals only caused a soil crust with soil strength values much lower than that of vehicles. The effects of animals are also much more vertical than lateral as with vehicles. Another important finding is the role that historical human activities play in such study areas and how it may influence results. The results in this study are aggravated by the historical human activities in this study area, as indicated. These historical activities were the main cause of the surface crusting, and the resultant low vegetation growth in the area. This, therefore, explains partially the relatively high control values and also the soil’s higher susceptibility to compaction due to vehicle ORD. The root density trials had very interesting and important results. Significant differences occurred between mean root density fractions across all tyre pressures at all three trial sites. The trend is that an increase in tyre pressure causes a decrease in root density distribution. These results show clearly that even lower tyre pressures are harmful, but are more environmental friendly than higher tyre pressures. Results of the second part of the study with regards to tourists' perceptions on ORD, and the impact of their activities on the environment, showed that the majority of tourists areignorant when it comes to the impacts of their activities on soil and vegetation. Tourists' had significantly variable demographic characteristics. Tourists' environmental perceptions varied, but a significant majority of tourists agreed that ORD has a negative impact on the environment. Contradictions exist between what they know or perceive as being damaging and what they prefer to act on. Results indicate a need for improved visitor education on the possible negative impacts of demands for ORD, and a need for government intervention with regards to the enforcement of legal measures to control ORD. The results also indicate that game guides and tourism operators can play a major role in educating the tourists. The results demonstrate that both an understanding of the chemical and physical factors influencing soil compaction, as well as tourists' environmental views are important in formulating a management strategy to control and manage these impacts. / Thesis (PhD)--University of Pretoria, 2014. / gm2014 / Animal and Wildlife Sciences / unrestricted

With the simple means of a digitized map and the wheel speed signals, it is possible to position a vehicle with an accuracy comparable to GPS. The positioning problem is a non-linear filtering problem and a particle filter has been applied to solve it. Two new approaches studied are the Auxiliary Particle Filter (APF), that aims at lowerering the variance of the error, and Rao-Blackwellization that exploits the linearities in the model. The results show that these methods require problems of higher complexity to fully utilize their advantages. Another aspect in this thesis has been to handle off-road driving scenarios, using dead reckoning. An off road detection mechanism has been developed and the results show that off-road driving can be detected accurately. The algorithm has been successfully implemented on a hand-held computer by quantizing the particle filter while keeping good filter performance.

<p>With the simple means of a digitized map and the wheel speed signals, it is possible to position a vehicle with an accuracy comparable to GPS. The positioning problem is a non-linear filtering problem and a particle filter has been applied to solve it. Two new approaches studied are the Auxiliary Particle Filter (APF), that aims at lowerering the variance of the error, and Rao-Blackwellization that exploits the linearities in the model. The results show that these methods require problems of higher complexity to fully utilize their advantages.</p><p>Another aspect in this thesis has been to handle off-road driving scenarios, using dead reckoning. An off road detection mechanism has been developed and the results show that off-road driving can be detected accurately. The algorithm has been successfully implemented on a hand-held computer by quantizing the particle filter while keeping good filter performance.</p>