Environmental Science

Permanent URI for this communityhttps://hdl.handle.net/10413/7404

Browse

Now showing 1 - 20 of 501

A Bayesian geo-statistical approach for plantation forest productivity assessment after the fast-track land reform in Zimbabwe.
(2023) Chinembiri, Tsikai Solomon.; Mutanga, Onisimo.; Dube, Timothy.
The principal objective of the current study was to investigate how the new generation multispectral remote sensing, along with variants of the Bayesian hierarchical geostatistical methodology, could handle prediction uncertainty of carbon (C) stock. The assessment of C stock prediction uncertainty was conducted in a managed and disturbed plantation forest ecosystem located in Manicaland province of Zimbabwe. To achieve this, the study made use of ancillary data from the multispectral (Landsat-8 and Sentinel-2) remote sensing platforms, which informed the application of different inferential and methodological variants within the Bayesian hierarchical geostatistical framework. Allometric equations suited for the target plantation tree species in the sampled region were used to derive C stock from Above ground Biomass (AGB) sampled on 500 m2 circular supports. These Bayesian geostatistical models utilized a combination of Landsat-8 and Sentinel-2 derived vegetation indices, along with climatic and topographic variables. The study found that the Normalized Difference Vegetation Index (𝑁𝐷𝑉𝐼), Distance to settlements (𝐷𝐼𝑆𝑇), and Soil Adjusted Vegetation Index (𝑆𝐴𝑉𝐼) played crucial roles in influencing the spatial distribution of C stock in the studied region. Enhanced Vegetation Index (𝐸𝑉𝐼) is an insignificant predictor for both Landsat-8 and Sentinel-2 driven C stock predictions. Among the tested Bayesian approaches, the spatially varying coefficient (SVC) model, the multi-source data-driven Bayesian geostatistical approach, and the frequentist geostatistical framework were examined. Regardless of the various specifications for independent variables in the predictive C stock modelling within the Bayesian framework, 𝑁𝐷𝑉𝐼 and 𝐷𝐼𝑆𝑇 emerged as significant predictors of the modelled response variable. The non-stationary and Sentinel-2 driven Bayesian hierarchical model, with 𝑁𝐷𝑉𝐼 and DIST covariables, proved to be the most effective prediction model in the studied plantation forest ecosystem in Zimbabwe. This best-performing C stock predictive model was subsequently used to predict C stock under both current (1970-2000) and future (SSP5-8.5) 2075 climate scenarios. The results of the Bayesian constructed hierarchical model indicate a significant shrinkage of forest C stock density and distribution under the future SSP5-8 (2075) business-as-usual climate projection. Basically, the findings of this study highlight the critical role of new generation multispectral remote sensing and Bayesian geostatistical approaches in assessing and predicting carbon stock uncertainty in forest ecosystems. These insights have significant implications for informed land management strategies, aligning with the goals and recommendations of the Intergovernmental Panel on Climate Change (IPCC) to effectively address climate challenges and enhance sustainable land management practices.
A critical assessment of the Namibian protected area management effectiveness tracking tool.
(2010) Mulonga, Samison Nzehengwa.; Dent, Mark Clifford.
Protected Areas (PAs) are one of the most effective mechanisms for biodiversity conservation. They are found in almost every country and have been adopted by the international community through various conventions and agreements. However setting aside areas as protected areas does not automatically qualify them to be effectively managed. Research around the world has shown that some PAs are not well managed due to different reasons in different parts of the world. Therefore it is important to determine management effectiveness of PAs to ascertain whether they are managed according to the objectives for which they were created. The Management Effectiveness Tracking Tool (METT) is one of the tools developed to evaluate management effectiveness of PAs around the world. The tool has been implemented in a number of countries including Namibia where it has been modified into the Namibia Management Effectiveness Tracking Tool (NAMETT) through the United Nations Development Programme and Global Environment Facility’s Strengthening the Protected Areas Network (SPAN) project. However the effectiveness of this tool in providing necessary information about PA management effectiveness was not ascertained before implementation. The Namibian PA management authorities on the other hand need a tool for determining management effectiveness of PAs for management decision-making and as part of their obligations through international conventions which they signed. The aim of this research study was to analyse and assess the NAMETT as a management effectiveness tool for PAs in Namibia, by looking at the strength and weakness of the tool. This will inform whether its worthwhile adopting the tool as a standard management effectiveness evaluation tool for Namibia’s PAs. To accomplish this NAMETT assessment data obtained from the two NAMETT assessments undertaken by SPAN project was analysed. Furthermore different qualitative techniques were used including a semi-structured questionnaire as part of a case study approach. A comprehensive literature review was undertaken in the process and links to students undertaking similar research projects and professionals in the PA management industry were established and complemented the research data. Data obtained from NAMETT assessment undertaken by SPAN project appear to provide a picture of the different levels of management effectiveness in Namibia’s PAs suggesting the tool could be adopted for management effectiveness of Namibia’s PAs. Research data and information gathered shows that at the moment there is no management effectiveness tracking tool in Namibia. PA management authorities lack the necessary management effectiveness information for decision making. Currently only reports, the Incident Book Monitoring System (IBMS) and park inspections are the only sources of information for PA management authorities in Namibia. These tools are inadequate as they do not provide information at a strategic level which can help show trends and weakness and strength in PA management. Therefore a METT tool based on the World Commission on Protected Area’s Framework of which Namibia is a signatory is warranted. The NAMETT provides good information but lacks a link or section that should highlight the health of the ecosystem or provide information on biodiversity. Furthermore the tool has shortfalls in terms of implementation training and guidelines to assist implementers. Despite this, stakeholders who participated in the research project indicated that the tool should be adopted as the standard management effectiveness tool for PAs in Namibia. This however should come with alignment of the tool to local conditions and development of implementation guidelines as well as linkage to other form of PA management tools such as game counts and the IBMS. There is lack of robust management system for PAs in Namibia which will consolidate implementation of NAMETT. Such a system should involve planning, implementation, reporting and adaptive management. Therefore if NAMETT is to be adopted there is a need for such a system to be in place to enable data and information from the different tools to be able to complement each other for informed decision making about PA management.
A review of the fluvial geomorphology monitoring of the receiving streams of the Mooi-Mgeni [River] Transfer Scheme Phase 1.
(2009) Hunter, Alistair Malcolm Scott.; Kotze, Donovan Charles.; Dent, Mark Clifford.; Archer, Lynette Deborah.
The Mgeni River is the major water resource for the eThekwini Metropolitan and Msunduzi Municipalities. At the end of 2002, the Mooi-Mgeni Transfer Scheme Phase 1, which transfers water from the Mooi River into the Mgeni catchment to augment the water supply to this region, was completed. The interbasin transfer of water resulted in the loss of habitat, erosion of the stream channel and transformation of the riparian zone in the receiving streams. Stream regulation resulting in an altered flow regime is considered the greatest threat to a riverine environment. An Environmental Management Plan (EMP), incorporating fluvial geomorphological monitoring procedures, was implemented to monitor the impact of the transfer on the receiving streams, the Mpofana and Lions Rivers, and to determine the rate and magnitude of erosion. A comparison of the geomorphological monitoring procedure of the EMP with best practice geomorphological monitoring derived from a review of the national and international stream geomorphological literature was conducted in this study. In addition, the implementation of the EMP geomorphological monitoring procedures was described and onsite observations of physical impacts on the receiving streams were completed. The geomorphological monitoring of the EMP included the use of erosion pins, survey of stream cross-sections and fixed-point photography. Photographs and data were collected from February 2003 to June 2006. The comparison of these monitoring methods against stream assessment best practices revealed the strengths and weaknesses of the geomorphological monitoring implemented in the receiving streams. Several key weaknesses were revealed. Firstly, an inadequate number of stream cross sections was included in the monitoring procedures. Secondly, although the erosion pins indicated some general trends in the erosion of the stream channel, they did not give a true impression of the rate and magnitude of change in slope and channel width of the stream, and the location of the erosion pins sites did not take into account the actual direction of flow during transfer as erosion pin sites were selected during low flow conditions. In addition, it was difficult to determine whether the erosion pins had been lost due to erosion or to turbulence. The results were difficult to assess and did not show whether the erosion was localised at the pins or the section of bank or stream profile. Thirdly, analysis of platform changes in the stream channel (e.g. through a comparison of aerial photograph sets) was lacking and no attempt was made to integrate the results from the different methods. Overall, the study concluded that the geomorphological monitoring of the EMP was limited, and it did not highlight the rate and magnitude of erosion in the receiving streams. Based on the findings of this study, recommendations are provided for geomorphological monitoring of the receiving streams of the Mooi Mgeni Transfer Scheme.
A systems-thinking based evaluation of predator conflict management on selected South African farms.
(2008) Snow, Timothy V.
The backbone of this study was a systems thinking based analysis of the management and control of predators as practiced in South Africa since the advent of Europeans in 1652. The first bounties were introduced for a variety of animal species in 1656. Many species became labeled as vermin and were persecuted, often with the intention of eradication. A variety of controls have been applied, of which many have not kept pace with contemporary thinking or technology, and which by simply killing predators fail to address the crux of the issue of predator – livestock conflict. Many of the methods used cannot be applied to specifically remove an individual damage-causing animal. Considerable collateral ecological damage is inflicted by the killing of animals regarded as innocent bystanders. The objective of the analysis was to highlight the futility of temporary solutions which fail to resolve the conflict in the long term. These quick fixes frequently perpetuate an ecological imbalance which exacerbates the predator – livestock conflict. The analysis used raw data from a questionnaire survey conducted by the Poison Working Group of the Endangered Wildlife Trust (EWT-PWG) (2003). The EWT-PWG intended to assess pesticide abuse as toxicant for predators by farmers, and to identify all control methods used. The data forthcoming was Cartesian in nature and a fixed snap-shot in time. This study sought to identify the root cause of the conflict by applying systems thinking which added the dimension of cause and effect interrogation. The study categorised and described predator conflict management methods as lethal or preventative, and assessed each category in archetypal terms from a systems thinking perspective. It also sought to identify leverage points, or small changes which have profound effects, to stimulate a change in approach to humanpredator conflict management. In order to assess and illustrate the positive change brought about by application of preventative methods, a small group of farmers who had initiated changes in their predator conflict management over the five years subsequent to the EWTPWG survey were selected from the original group for reassessment. Through evaluation of predator conflict management methods from a systems thinking perspective, and by probing learning processes, the shortcomings or failure of inappropriate management responses to conflict situations were shown to exacerbate conflicts. Contrarily, it was illustrated that application of systems thinking and a process of addressing the root cause of conflict issues in predator conflict management, was a longer term solution. The study illustrated that application of long term proactive prevention and conflict avoidance principles, can offer long term solutions for predator conflict managers.
Addressing genetics misconceptions with an educational game.
(2008) Baxter, David.; Amory, Alan M.
This dissertation describes the design, development and formative evaluation of an educational adventure game entitled Food for Thought to address student misconceptions in genetics within the context of a development research paradigm, and reflects on the lessons learnt during the process. The current investigation was a response to an assessment of learning misconceptions in genetics. Several factors were identified as contributing to these problems with a focus on the abstract nature of the subject and the decontextualised manner in which students encounter these concepts. The tenacity of the problem suggested the need for of a novel intervention. A constructivist concept of learning emphasises active learners internally constructing their own meaning in rich complex environments. While not a theory of teaching, it offers a number of principles to guide the design of learning environments. Elements from computer based adventure games embody aspects of these principles and offer possibilities of developing a tool to address student misconceptions. Here, learners may explore biological concepts as they engage in contextual problems embedded in the narrative structure of a detailed and immersive virtual world. The implementation of the design was guided by a number of conceptual models, namely the Game Object Model (GOM) and Game Achievement Model (GAM) which clarify the relationship between pedagogical principles and game design elements. The identification of specific learning misconceptions provided the basis for developing a set of learning objectives for the game which were used as a foundation for the design of the environment, which was then created using a combination of commercial and proprietary 3D graphic and image editing software. Both the GAM and GOM are effective tools for categorizing a variety of different components in a very complex development. A formative evaluation of the game was undertaken probing both expert and user (student) responses through post-gameplay questionnaires and interviews. The game was favourably received, with feedback and suggestions on improvements. Most notable was the need for greater guidance in the game environment. In addition Activity theory was employed as framework of analysis. Activity systems for both players and the designer were developed and contradictions within and between them analysed. These were used to modify the original designer activity system and in so doing refine the practice of game design in the context of the development research paradigm.
Addressing poverty and local livelihoods in the context of conservation : a case study of the proposed Ngelengele Nature Reserve.
(2006) Godinho, Elizeth.; Nyambe, Nyambe.; Densham, Drummond.
Many people in Africa, due to high levels of poverty, rely directly on natural resources and the environment for their livelihoods. Different mechanisms have been employed over the years to address poverty and local livelihoods in the context of conservation. Community Conservation Areas and the sustainable livelihood approach are examples of these mechanisms. Increasingly, these and other mechanisms have reinforced the view that unless the risks and opportunities presented by poverty to local livelihoods are addressed, many conservation efforts are bound to fail. The research reported here was based on the premise that appropriate mechanisms that explicitly address poverty and local livelihoods are a necessary prerequisite to successfully engaging local people in conservation. Such mechanisms assure the sustainability of local livelihoods and present opportunities for conservation initiatives to succeed within the context of human societies that are dependent on associated ecosystems and resources. The Maloti-Drakensberg mountains region in South Africa was the study site and the proposed Ngelengele Nature Reserve, a Community Conservation Area, was used as a case study. The amaHlubi community people constituted the study's respondents. The study was largely qualitative, drawing on both primary and secondary sources of data in the form of interviewer-administered questionnaire and documentary analysis respectively. Field observations and discussions with respondents complemented the interviews. By adopting the sustainable livelihoods framework to understand and analyse the livelihoods of the amaHlubi community, the study highlighted concerns about livelihood assets with the conclusion that there is a high dependence on natural resources mainly for domestic purposes, and in general most of the assets are non existent. The study also highlighted the level of awareness and community support towards Ngelengele Nature Reserve, as well as the reserve's implications on local livelihoods. Although some stated that the objectives of Ngelengele Nature Reserve remain unclear, the majority of respondents showed high expectations and support for the project.
Agrohydrological sensitivity analyses with regard to projected climate change in Southern Africa.
(1997) Lowe, Kerry Lynne.; Schulze, Roland Edgar.
Climate change resulting from the augmented "greenhouse effect" is likely to have significant effects on the terrestrial hydrological system and the social and ecological systems linked to it. Climate change could potentially affect inputs to the agrohydrological system such as rainfall, temperature and potential evaporation; processes within the system such as vegetation dynamics and crop production; and hydrological responses such as runoff, recharge of soil water into the vadose zone and net irrigation demand. This study outlines the use of a daily water budget model, ACRU, and SCENGEN, a climate change scenario generator, to assess potential impacts of global climate change on agricultural production and hydrological responses in southern Africa. This study also considers potential impacts of climate change on plant response which may determine the extent of potential impacts of climate change on agricultural production and hydrological response. Two approaches to climate change impact studies are adopted for use in this study. The first, and more conventional approach considers the impact of a specified climate change scenario, in this case developed with the use of SCENGEN, on the terrestrial hydrological system. The second approach considers the degree of climate change, in this case precipitation change, required to perturb the hydrological system significantly in the various climate regimes found in southern Africa. A comparative analysis of the sensitivity of selected hydrological responses to climate change produced the following results, in ascending order of sensitivity: net irrigation demand < stormflow response < runoff < recharge into the vadose zone. The impacts of a specific climate scenario change on hydrological responses produced unexpected results. A general decrease in mean annual precipitation over southern Africa is predicted for the future with SCENGEN. However, widespread simulated increases in runoff, soil moisture content in the A- and B-horizon and recharge into the vadose zone are obtained. These increases are a product of the CO2 "fertilisation" feedback, which is incorporated as a maximum transpiration suppression routine, in the ACRU model. Net irrigation demand, which is not linked to this routine, is simulated to increase in the future.
Air quality management in the uMhlathuze municipality using air dispersion modelling.
(2007) Haripursad, Yegambal.; Diab, Roseanne Denise.
Air pollution has increased over time due to human population growth, industrialisation and other economic activities which have led to global and localised deterioration in air quality. The uMhlathuze Municipality, located on the KwaZulu-Natal North Coast is one such local area that has a rapidly developing Industrial Development Zone, currently comprising many large and small scale industries. These large-scale operations are amongst South Africa’s largest process industries and operate continuous combustion processes which release significant quantities of air pollutants into the atmosphere. These pollutants include reduced sulphur gases, mercaptans, hydrogen sulphide, sulphur dioxide (SO2), sulphur trioxide, carbon dioxide, particulate fluoride and ammonia. In light of the promulgation of the National Environmental Management: Air Quality Act (AQA) of 2004 and the need to assess ambient air quality, the contribution of air dispersion modelling to ambient air quality management in the uMhlathuze Municipality was assessed using SO2 as an indicator pollutant. The Gaussian puff urban air dispersion model called Calpuff was used to model five scenarios including a control run with actual emissions data; a worst-case run using permitted emissions data; and three emissions reduction scenarios using 25%, 50% and 75% reductions of the permitted data.. The results of these modelling scenarios were compared with results of other modelling studies recently conducted in the uMhlathuze Municipality, as well as with the South African Ambient Air Quality Standards (SAAAQS) for SO2. The results revealed that the permitted emissions scenario led to exceedances of the SAAAQS 1-hour and 24-hour average concentrations over most of the uMhlathuze Municipal area. The use of the permitted emissions values produced higher SO2 concentrations over the study area than the control run that comprised current emissions values. The control scenario produced similar results to the scenario in which there was a 50% reduction in permitted emissions data and suggests that the industries are operating at half of their permitted levels of SO2 emissions. The reduction of the permitted emission by 75% shows a significant decrease in the area exceeding the SAAAQS 1-hour standard, and compliance with the SAAAQS 24-hour and annual average standards. The results of this study for the control scenario based on actual emissions were higher than previous studies conducted in uMhlathuze due to a larger quantity of SO2 emissions used in the modelling exercises, different meteorological data sets and different air dispersion models used. However, there is a close correspondence between the Airshed (2006) results and this study when similar quantities of SO2 emissions were modelled in the permitted emissions scenario. In view of the exceedances experienced in the control run and permitted emissions scenarios, it is likely that under the AQA, some reduction in emissions will be required. In line with the Department of Environmental Affairs and Tourism National Framework classification system, the City of uMhlathuze is likely to fall under a Class 4 area, in which ambient concentrations of SO2 can pose a threat to the health and well-being of people. Immediate air quality management action plans that have specific timeframes for compliance with the ambient standards are required. The National Framework notes that the air quality impact of an industry will be assessed before an Atmospheric Emission License is granted and implies that each industry is required to undertake an air quality specialist study to determine its individual impact on ambient air quality. The air quality specialist study should include air dispersion modelling to assess the ambient SO2 concentrations; a health risk assessment based on the results of the dispersion modelling; and mitigation measures that are required to ensure compliance with ambient standards through the use of the Best Practicable Environmental Option (BPEO).
An assessment of the appropriateness of agricultural extension education in South Africa.
(2008) Worth, Steven Hugh.; Modi, Albert Thembinkosi.
This thesis is about agricultural extension education. The context is agricultural extension in South Africa. It addresses the following questions: To what extent does current agricultural extension education in South Africa adequately reflect the current and changing educational and developmental imperatives? To what extent does it adequately equip extension officers and other agricultural development practitioners to deliver relevant support to farmers and farming communities? In short, how relevant is the training received by South African Agricultural Extension practitioners? The South African government has made significant changes in the policy environment governing agriculture. While the majority of the policy changes fall outside the scope of this research, it can be safely argued, as noted in the current Strategy for South African Agriculture, that the changes are fundamental. The changes redirect agriculture to the majority population which has hitherto been marginalised and generally denied meaningful access to the agricultural sector of the South African economy. To implement these changes, the agricultural sector will need appropriate skills – skills which, it is submitted – are largely lacking within the agricultural extension service and, more relevantly to this study, in Agricultural Extension curricula. In addition to the foregoing, assumptions about farmers and their roles in technology and information creation and consumption, assumptions about the roles of tertiary institutions in the triad of teaching, extension and research and indeed about the triad itself need to be challenged. A system of education which has its origins in the 1800s (before even the industrial revolution, much less the digital revolution) needs, per force, to be interrogated regularly to ensure that it delivers according to the demands of the exigencies of the time. Similarly, assumptions about the aim of development and in particular agricultural development have been questioned in many parts of the world. And yet it is submitted that in South Africa, the basic extension methodologies have not changed in any fundamental way; rather they have adopted some of the outer trappings of new approaches, without assessing the fundamentals of the core extension approach. It is believed that extension is in need of a serious review and that it is timely to do so. Recent research in Africa and elsewhere in the world indicates that extension needs be reconstructed on a different set of operational objectives led by a different vision. The extension strategy herein presented is built around a vision which places the focus on the farmer (and other land users) in the context not of technology, but of creating prosperity. The vision implies that the purpose of agricultural extension is to facilitate the establishment of self-reliant farmers who are contributing to widespread prosperity. The dual outcomes of self-reliant farmers and widespread prosperity are meant to be realised through a new set of =rules of engagement‘. Prosperity is derived out of farmers working together, sharing information, and learning together. Self-reliant farmers are an outcome of a learning partnership between farmers and extension practitioners. This study was conducted in a series of stages. The first thrust examined the nature of Agricultural Extension and the assumptions on which it is predicated. The result of this interrogation was to propose a new concept for Agricultural Extension – Agriflection – which is a learning-based concept aimed at improving the sustainability of the livelihoods of farmers through iterative development processes fostered through a learning agenda that is facilitated by an appropriately trained Agricultural Extension practitioner. To realise such a vision, it is essential that the mission of the extension service be recast to reflect the dynamics of the implications of the vision. The key elements of the mission are, therefore, client-responsiveness and partnerships. The power to realise the vision rests in three critical aspects. First is the capacity of the extension service to engage with its clients as genuine partners in a shared learning agenda. The second is the capacity of the extension service to engage with the many other agencies and organisations which supply goods and services to farmers and land users. The third is ensuring that engagements with farmers support sustainable development, that is, that production of food, fibre and fuel is socially just, economically sustainable and environmentally sustainable. This new vision and mission lay the foundation for a fundamental shift in the way agricultural extension is positioned, resourced, implemented and evaluated. The strategic goals, principles and values presented in this strategy are built on this foundation, and they, in turn, create the framework for constructing the operational plans of the extension service as well as for management and measurement of the service. The second thrust of the study was to filter the Agriflection concept through South African educational and agricultural policy. Given that the agricultural frontier is subject to change in focus and priorities, it was reasoned that the training and education of would-be extension practitioners needs to be able to respond to changes in methods and in the field. The National Government has adopted the outcomes-based model as the general structure for curriculum development. Further sustainable development/livelihoods has been adopted as the general framework for development. Outcomes-based education and sustainable development/livelihoods provide a framework for studying and developing curricula. A tool that enables curriculum analysis and development which allows for adjustment to changing imperatives while maintaining integrity in terms of education and development, would be valuable for tertiary institutions training extension officers. The result of this second thrust was the development of curriculum markers that encapsulated what non-technical knowledge and skills (i.e. Agricultural Extension knowledge and skills) were needed to be able to deliver on the imperatives of the transformation agenda of current agricultural policy. Thirty-four markers were identified. The third thrust of the study was to create a credible method to evaluate Agricultural Extension curricula and to capture and analyse data. A detailed review of methods and approaches was made resulting in fashioning the Theory-led Instructional-Design Curriculum Evaluation (TICE) method. One of the primary facets of this six-process method is questioning of the assumptions on which the discipline of Agricultural Extension is based. Such a questioning would lead to a new theory to govern the evaluation of curriculum. Ancillary to the TICE method were the methods of data collection and analysis. The study consolidated these in presence and efficacy factors. These factors measured the presence of the 34 markers in Agricultural Extension curricula and the extent to which they were addressed, if present. The fourth thrust of the study was the detailed evaluation of curricula of qualifications most commonly held by public sector Agricultural Extension practitioners. The study examined the curricula of agricultural diplomas, of three- and four-year agricultural degrees and of one-year postgraduate qualifications offered by Colleges of Agriculture and selected Universities and Universities of Technology. The fifth thrust was to conduct corroborative investigations in the public sector. This was done by surveying Agricultural Extension practitioners asking them to evaluate the extent to which they believed they have knowledge and/or skill represented by the 34 curricula markers. In addition, a brief analysis was made of Agricultural Extension practitioner job descriptions used in the public sector. This was done to determine what knowledge and skills were expected of Agricultural Extension practitioners and comparing this to the 34 markers. The study revealed that there is very limited Agricultural Extension training offered in the curricula of qualifications held by the majority of public sector Agricultural Extension practitioners. Further, using the 34 markers as the touchstone, it was determined that the current curricula do not adequately equip public sector Agricultural Extension practitioners to deliver on the agenda of current South African agricultural policy. Without extensive revision of curricula in terms of both the quantity and content of extension training, the South African public sector Agricultural Extension service will not be able to realise the intended transformation of agriculture. Its key operatives will not have the knowledge and skills needed to do so. This is a unique study. No study of its kind has ever been conducted in South Africa. Numerous studies have been conducted into the training needs of Agricultural Extension practitioners. None have gone to the extent of questioning the assumptions on which Agricultural Extension is based. None have made a critical examination of curricula in the light of current educational and agricultural policy. This study found that there is an urgent need for serious attention to be given the purpose, scope, outcomes of Agricultural Extension higher education in South Africa to ensure that it can contribute to the positive and sustainable transformation of agriculture.
An investigation into using GIS in electrification and network planning in rural KwaZulu-Natal.
(2006) Barnard, Jennifer B.; Ahmed, Fethi B.
The South African Government has set a target of universal access to basic electricity by the year 2012. Free basic electricity is defined as the amount of electricity sufficient to provide basic lighting, media access, water heating and ironing with on-grid electricity; or basic lighting and media access for a non-grid system. Eskom Distribution, in conjunction with local municipalities, is responsible for the outstanding electrification predominantly in rural areas. In KwaZulu-Natal, mountainous terrain and scattered settlement patterns of communities complicate the achievement of this goal. This study was aimed at using GIS to address the urgent need to plan electrification, firstly by identifying areas that need electrification and secondly by prioritising those areas according to set principles. Electrification areas were effectively identified and prioritised from both a need and capability of supply aspect. The study then aimed at designing the shortest networks from the grid to those identified electrification areas. To determine electrification areas spatially, electoral areas (EAs) demarcated as rural during the run up to the 1994 elections were used to identify rural areas; and Ethekwini Metropolitan Municipality, current electrification projects, reserves and a buffer zone around existing transformers excluded. Household point data was used to polygonize the remaining area, and those polygons were aggregated on their calculated area to create future rural electrification areas (FREA). A points and weighting system; based on one initially used in Namibia and further developed in an electrification planning model by RAPS Consulting, CSIR and DME to prioritise villages for electrification; was applied to calculate point scores for each FREA and other criteria such as distance from a network with capacity considered to determine a prioritised list of FREA that can be electrified immediately. Roads, land cover, household positions and slope were used to design the shortest path from the grid to the three highest scoring FREA. Each layer was reclassified, ratings applied and the layers combined to successfully determine the final path in terms of the criteria used. Interest in using GIS for spatial planning has led to a GIS Initiative Group (GISIG) being formed at Eskom Distribution in Eastern Region to address data collection, co-ordination of planning, tools written previously but never implemented being re-evaluated and, more recently, new tools being designed. However, much is still needed in terms of research, resolving of data quality issues, testing of points and weighting systems, and for functionally independent sections to work together on making changes to age-old system structures and processes before any of the recommendations resulting from this study can be effectively implemented.
Analysis and mapping of basic communal land administration systems using participatory GPS and GIS : a case study of Makurung Village.
(2006) Maleka, Mampone Morris.; Rugege, Denis.
Participatory GPS and GIS mapping is a mapping process that involves active participation of the local communities with the assistance of outsiders who are experts in the field. The objective of Participatory GPS and GIS mapping is to produce a technically accurate and socially acceptable participatory map and to facilitate skills transfer to the participant community. A basic communal land administration system is a land administration structure responsible for the administration of a local, elementary area of jurisdiction (a village) occupied by a tribe whose rights to land are derived from shared rules determining access and is normally led by an Induna. The analysis of such a structure could provide a foundation for the implementation of Communal Land Rights Act, 2004 (Act No 11 of 2004) that is, the transfer of communal lands to communities. A sub-metre accuracy is obtainable after post-processing differential correction as acclaimed by Trimble on the Geo-XT™ GPS unit and proven in the Ukulinga case study. Participatory GPS and GIS mapping guarantees effective and efficient skills transfer to participant communities and accurate recording of boundary data. Maps produced through Participatory GPS and GIS mapping are widely acceptable since they are preceded by discussions and subsequent consensus on boundary data points prior to actual recording, thereof. The study was designed to analyze basic communal land administration systems and to develop a methodology for mapping them. A successful implementation of the Communal Land Rights Act, 2004 required spatial and related information on land administration structures A Participatory mapping methodology designed was tested in two case studies and found to be reasonably accurate.
Analysis of geographical and temporal patterns of malaria transmission in Limpopo Province, South Africa using Bayesian geo-statistical modelling.
(2013) Mgabisa, Aphelele Ronnie.; Gebreslasie, Michael Teweldemedhin.
South Africa is at the southern fringe of sub-Saharan African countries which persist in experiencing malaria transmission. The purpose of the study is to analyse the geographical and temporal patterns of malaria transmission from 2000 to 2011 using Bayesian geostatistical modelling in Limpopo Province, South Africa. Hereafter, develop malaria case data-driven spatio-temporal models to assess malaria transmission in Limpopo Province. Malaria case data was acquired from the South African Medical Research Council (MRC). Population data was acquired from AfriPopo; and Normalised Difference Vegetation Index (NDVI), Land Surface Temperature (LST) and Land Cover data were acquired from MODerate-resolution Imaging Spectro-radiometer (MODIS). Rainfall, Altitude and distance to water bodies’ data were acquired from African Data Dissemination Service (ADDS), United States Geological Survey (USGS) and Environmental Systems Research Institute (ESRI), respectively. Bayesian spatio-temporal incidence models were formulated for Gibbs variable selection and models were fitted using the best set of environmental factors. Modelbased predictions were obtained over a regular grid of 1 x 1km. spatial resolution covering the entire province and expressed as rates of per 1 000 inhabitants for the year 2010. To assess the performance of the predicted malaria incidence risk maps, the predictions and field observations were compared. The best set of environmental factors selected by variable selection was Altitude and the night temperature of two months before the case was reported. The environmental factors were then used for model fitting and all of the covariates were important on malaria risk. Predictions were done using all the environmental factors. The predictions showed that Vhembe and Mopani district municipalities have high malaria transmission as compared to other district municipalities in Limpopo Province. Assessment of predictive performance showed scatter plots with the coefficient of determination ( R² ). The values representing the statistical correlation represented by the coefficient of determination ( R² ) were 0.9798 (January), 0.8736 (February), 0.8152 (March), 0.8861 (April), 0.9949 (May), 0.3838 (June), 0.7794 (July), 0.9235 (September), 0.8966 (October), 0.9834 (November) and 0.8958 (December). August had two values reported and predicted which resulted in R² of 1. The numbers of the The produced malaria incidence maps can possibly be considered as one of the baselines for future malaria control programmes. The results highlighted the risk factors of malaria in Limpopo Province which are the most important characteristics of malaria transmission.
Analysis of implementation constraints for planning programs : a case study of the city of Maputo, Mozambique.
(2005) Massinga, Jadwiga Soltys.; Turkstra, Jan.; Rugege, Denis.; Forjaz, José.
No abstract available.
Analysis of rhino poaching incidences and management strategies in South Africa.
(2016) Moneron, Sade Leigh.; Ngetar, Njoya Silas.
The illegal hunting and global trade in wildlife and wildlife products is a transnational, highly organised crime that threatens the survival of many endangered species. The rhinoceros is a well-known example of this trade as the demand for rhino horn for use in East Asia has resulted in the global decline of rhino populations, resulting in the Western Black rhino in Africa (Diceros bicornis longipes) officially being declared extinct in 2011. Although poaching has always existed, the number of African rhinos killed by poachers has escalated in the past eight years with at least 1 338 rhinos killed by poachers across Africa in 2015. This is the highest level since the rhino poaching crisis began in 2008, resulting in at least 5 940 African rhinos being killed. The majority of these incidences occurred within South Africa. South Africa plays a leading role in the conservation of the African rhino, currently conserving 83% of the African rhino population. However, it has been suggested that should poaching continue to increase as it has done over the past few years the rhino population in South Africa may begin to decline as early as 2016. South Africa’s upsurge in rhino poaching over the last few years has given rise to a kaleidoscope of debates on how to reduce poaching. An understanding of the different management strategies and their effectiveness would play a large role in identifying which method or combinations of methods work best to reduce poaching. The second chapter of this dissertation thus critically analyses the past, current and proposed strategies that are relevant to reducing incidences of rhino poaching using empirical literature from various scholars and stakeholders and attempts to provide insight into which strategy or combination of strategies is best suited to reduce poaching. As poaching involves a combination of aspects, it is clear that no one strategy or management tool will address all of these aspects on its own, and if implemented in isolation will not be successful. A combination of strategies that address all aspects of poaching needs to be working concurrently to decrease poaching levels. Law enforcement is one such management strategy crucial in the reduction of poaching and with increasing poaching incidents, law enforcement efforts in the form of deployment of anti-poaching unit, focused on high risk areas would provide for a more efficient and effective use of resources in reducing poaching incidences. The third chapter of this dissertation sought to investigate the spatial and temporal patterns of rhino poaching in the Hluhluwe-iMfolozi Park (HiP) between 1990 and 2013 and examine the relationships between observed patterns of poaching and biophysical and human variables using Geographic Information Systems (GIS). The results reveal poaching hot spots, and spatial and temporal variation in poaching incidences. Biophysical and human variables were also found to influence poaching densities differently depending on where they occurred spatially or temporally. The successful use of GIS in this analysis validates its potential as a geospatial tool for understanding the spatial and temporal distribution patterns of rhino poaching in the HiP. Understanding these patterns is crucial for future anti-poaching planning and mitigation of poaching activities with protected areas.
Analysis of the geographical patterns of malaria transmission in KwaZulu-Natal, South Africa using Bayesian spatio-temporal modelling.
(2013) Ndlovu, Noluthando.; Gebreslasie, Michael Teweldemedhin.; Vounatsou, Penelope.
Malaria is one of the most important public health issues that is still affecting millions of people around the world, especially in Africa. Africa accounted for 80% of the 216 million cases worldwide and 91% of deaths. It poses serious economic burdens on communities and countries at large. However, through temporal and spatial mapping of the disease populations at risk can be identified timeously and resources distributed accordingly. Since malaria is a climatic disease geostatistical approaches can be utilised in modelling its spatial distribution. Bayesian geostatistical methods enable the mathematical descriptions of the environment-disease association. Significant environmental predictors of malaria transmission can be identified which can also allow for the development of a malaria epidemic prediction model. This model can serve as a surveillance system for early detection and containment of the disease. Therefore, it is crucial to understand the complex dynamics of malaria transmission so malaria control programmes can be more effective and efficient in managing this public health issue. In South Africa, malaria is transmitted in 3 provinces: KwaZulu-Natal, Mpumalanga and Limpopo. Although malaria is highly seasonal in these areas and KwaZulu-Natal has experienced tremendous achievements in decreasing morbidity and mortality due to malaria, it still remains in an unstable condition that needs constant control and surveillance. The aim of this study was to investigate which environmental/climatic variables are drivers of malaria incidence in KwaZulu-Natal and subsequently develop methods to produce risk maps using Bayesian spatio-temporal modelling. It emerged from the research that the main environmental/climatic drivers of malaria incidence in KwaZulu-Natal were the day temperature of the previous month, altitude and forest land cover type. This was due to the different ways these three factors affect the three-way interaction of the vector, the parasite and the human host. The predicted risk maps showed that incidence rates ranged from 0.2 to 5 per 1000 inhabitants in the study area. This prediction was based on only the climatic factors, however, non-climatic factors also affect malaria transmission through vector control strategies like Indoor Residual Spraying among others.
Analysis of vegetation fragmentation and impacts using remote sensing techniques in the Eastern Arc Mountains of Tanzania.
(2014) Ojoyi, Mercy Mwanikah.; Mutanga, Onisimo.; Odindi, John Odhiambo.
The Eastern Arc Mountains of Tanzania forms part of the Eastern Afromontane Biodiversity Hotspots, listed among the global World Wide Fund for Nature's (WWF) priority ecoregions. However, the region is threatened by fragmentation and habitat modification resulting from competing forms of land uses, which is in turn threatening biodiversity conservation, planning and management efforts. To determine vulnerability that can inform long-term conservation and management of the biodiversity hotspots, an in-depth understanding of the qualitative and quantitative nature of ecosystems is a pre-requisite. The overall goal of this study was to quantify fragmentation, investigate its impacts on tree species diversity, abundance and biomass and to identify management interventions in the Eastern Arc Mountains of Tanzania. Using ecological field based measurements and a series of LANDSAT and RapidEye satellite imagery, fragstats metrics showed dynamic fragmentation patterns at both spatial and temporal scales. Furthermore, species diversity was predicted better with customized environmental variables using the Generic Algorithm for Rule-Set Prediction (GARP) model, which recorded an Area under Curve (AUC) of 0.89. In addition, Poisson regression results showed different responses by individual tree species to patch area dynamics, habitat status and soil nitrogen. Partial Least Squares and Random Forest models were used to determine above ground biomass prediction based on a combination of edaphic variables and vegetation indices. Total biomass estimations decreased from 1162 ton ha-1 in 1980 to 285.38 ton ha-1 in 2012. As a reference point in formulation of policy insights based on strong scientific and empirical knowledge, socio-economic factors influencing vulnerability of ecosystems and management interventions were examined using remotely sensed and empirical data from 335 households. The multiple logistic regression model indicated habitat fragmentation and forest burning as key conservation threats while low income level (54.62%) and limited knowledge on environmental conservation (18.51%) were identified as major catalysts to ecosystem vulnerability. The study identified livelihood diversification, effective institutional frameworks and afforestation programmes as major intervention measures. The overall study shows the effectiveness of remote sensing techniques in ecological studies and how results can be used to inform decisions for addressing complex ecological challenges in the tropics.
Analyzing an orthophoto mapping system using system analysis, SWOT and client satisfaction survey : a case study of the Chief Directorate of Surveys and Mapping, Republic of South Africa
(2010) Mnyengeza, Mnqweno.; Chimhamhiwa, Dorman.
An orthophoto map is made from a combination of different geospatial datasets such as relief, imagery, powerlines and annotation. These data sets are usually generated by different divisions within national mapping agencies. Often, when an orthophoto mapping project is to be undertaken, other functions within and outside the system, are actuated. Examples of such functions include; photogrammetric scanning, digital elevation capturing, aerial triangulation, ancillary data and imagery acquisition and map compilation. This research is underpinned by the hypothesis that different components that supply data required for generating orthophoto maps do not work as a coherent whole. This behaviour impacts negatively on the production of orthophoto maps as well as the quality of the end product and can have spill over effects on service delivery. In this research, systems analysis, client satisfaction survey and SWOT (Strengths, Weaknesses, Opportunities and Threats) analysis are used as a collective set of tools to analyze an orthophoto mapping system (OMS) in order to mitigate this unwanted behaviour. The case of orthophoto map production at the Chief Directorate of Surveys and Mapping (CDSM) in South Africa is used. First, systems analysis, which uses the Data Flow Diagram (DFD) technique, is employed to depict the system‘s data stores, processes and data flows. This approach helps to show how the current system works thereby assisting to pin point areas that require improvement. After presenting the system ‘s processes, data stores and data flows, a client satisfaction survey, built on the criteria of; accuracy, completeness, correctness and accessibility of geospatial datasets, is conducted on one of the data stores – the Topographical Information System (TIS) database. Finally, a SWOT analysis is then done on the whole OMS to evaluate the internal and external environment under which the current system operates in. Gaps are identified and recommendations suggested. Although in this case, the recommendations are built based on the CDSM case study, it is believed they can benefit other OMS’s in similar operating conditions elsewhere.
The anthropogenic impacts of urbanization and industrialisation on the water quality, ecology and health status of the Palmiet River catchment in Durban, KwaZulu-Natal.
(2005) Naidoo, Kushela.
Water, a fundamental and irreplaceable resource, is an all-pervasive issue that underpins the social fabric of every society. Rapid population growth and expansion of human activities increases the amount of waste and pollution generated and many local authorities are encountering serious water pollution problems, often concentrated in the lower reaches of catchments and adjacent coastal areas. This problem is predominantly acute in urbanized catchment areas, where waste is concentrated into localized areas, and the authorities are constantly under pressure to provide adequate management and mitigation measures. The Palmiet River system, located in the northern fringe of the city of Durban and draining the highly industrialized Pinetown region in KwaZulu-Natal, South Africa, illustrates a system that has been altered due to human impacts, particularly in its headwaters where the industrial sites are located and, in the lower catchment where a densely populated informal settlement occurs. A range of chemical and biotic indicators were monitored seasonally and these confirm the influence of the aforementioned human impacts on the quality of the Palmiet River system. Results from the present study were compared with studies conducted over a period of two decades and clearly demonstrate a pattern of increasing pollution loads for the upper and lower parts of the catchment. This study confirms that the Palmiet River is severely degraded in its lower reaches whilst the middle reaches of the catchment where a nature reserve is located is still in a fairly pristine condition. Additionally, the Palmiet River issues discussed in this thesis have direct impacts on the estuarine and adjacent marine ecosystems.
Application of a framework to assess wildlife policy and its implementation in Mocambique.
(2004) Soto, Bartolomeu.; Breen, Charles Mackie.
Wildlife management in Moryambique has had a troubled history. The end of civil war and installment of a democratic Government provided opportunity to redefine policy and implementation of conservation. Weakened by civil strife and with wildlife decimated in many areas, Government sought approaches to conservation that would promote participation by investors and civil society, particularly rural communities. The intention is to acknowledge the rights of rural people to resources and the benefits that can accrue from their use. Partnerships are seen as a way in which Government can bring the required financial and human resources to bear whilst at the same time engendering positive attitudes to conservation in general, and to policy in particular. The purpose of this research is to examine, using two case study conservation areas, the consequences of Government's attempts to implement its policy. The philosophical basis for the research is that policy reform and implementation should be envisaged as a complex system comprising many interactions and that when this complexity is not acknowledged and addressed systemically, it predisposes the process of policy reform and implementation to failure. A principal cause of failure is considered to be that assumptions are not made explicit and this results in development and application of an approach that does not accord with reality. Further, because of the networked nature of the system, failure at one point can be magnified as its consequences are propagated through the system. A conceptual framework for policy reform and implementation is developed. This exposes some critical assumptions about Government's capacity to implement policy and the ways in which implementation is experienced by stakeholders, especially local communities. Context is provided by tracing the evolution of approaches to conservation in Moryambique from the pre-colonial era to the present. The findings are that Government does not have the capacity to implement its conservation policy and this is shown to have serious implications for how local people perceive and respond to Government approaches to conservation. Causal factors are analysed and assessed. It is concluded that the process of policy reform and implementation is complex but that a systems approach provides a simple and easily comprehended way in which this complexity can be interpreted and taken into account with potentially very significant benefits. Perceptions are shown to be a powerful determinant of response to policy reform and implementation. As these are commonly a basis for destructive tensions between parties, it is suggested that research directed at defining the principles that should underpin management of perceptions and tensions should be encouraged.
The application of deep learning for remote sensing of soil organic carbon stocks distribution in South Africa = Ukusetshenziswa kokufunda okujulile kokuzwa kude kokusatshalaliswa kwesitokwe sekhabhoni ephilayo enhlabathini eNingizimu Afrikha.
(2022) Odebiri, Omosalewa Olamide.; Mutanga, Onisimo.; Odindi, John Odhiambo.
Soil organic carbon (SOC) is a vital measure for ecosystem health and offers opportunities to understand carbon fluxes and associated implications. However, unprecedented anthropogenic disturbances have significantly altered SOC distribution across the globe, leading to considerable carbon losses. In addition, reliable SOC estimates, particularly over large spatial extents remain a major challenge due to among others limited sample points, quality of simulation data and suitable algorithms. Remote sensing (RS) approaches have emerged as a suitable alternative to field and laboratory SOC determination, especially at large spatial extent. Nevertheless, reliable determination of SOC distribution using RS data requires robust analytical approaches. Compared to linear and classical machine learning (ML) models, deep learning (DL) models offer a considerable improvement in data analysis due to their ability to extract more representative features and identify complex spatial patterns associated with big data. Hence, advancements in remote sensing, proliferation of big data, and deep learning architecture offer great potential for large-scale SOC mapping. However, there is paucity in literature on the application of DL-based remote sensing approaches for SOC prediction. To this end, this study is aimed at exploring DL-based approaches for the remote sensing of SOC stocks distribution across South Africa. The first objective sought to provide a synopsis of the use of traditional neural network (TNN) and DL-based remote sensing of SOC with emphasis on basic concepts, differences, similarities and limitations, while the second objective provided an in-depth review of the history, utility, challenges, and prospects of DL-based remote sensing approaches for mapping SOC. A quantitative evaluation between the use of TNN and DL frameworks was also conducted. Findings show that majority of published literature were conducted in the Northern Hemisphere while Africa have only four publications. Results also reveal that most studies adopted hyperspectral data, particularly spectrometers as compared to multispectral data. In comparison to DL (10%), TNN (90%) models were more commonly utilized in the literature; yet, DL models produced higher median accuracy (93%) than TNN (85%) models. The review concludes by highlighting future opportunities for retrieving SOC from remotely sensed data using DL frameworks. The third objective compared the accuracy of DL—deep neural network (DNN) model and a TNN—artificial neural network (ANN), as well as other popular classical ML models that include random forest (RF) and support vector machine (SVM), for national scale SOC mapping using Sentinel-3 data. With a root mean square error (RMSE) of 10.35 t/ha, the DNN model produced the best results, followed by RF (11.2 t/ha), ANN (11.6 t/ha), and SVM (13.6 t/ha). The DNN's analytical abilities, combined with its capacity to handle large amounts of data is a key advantage over other classical ML models. Having established the superiority of DL models over TNN and other classical models, the fourth objective focused on investigating SOC stocks distribution across South Africa’s major land uses, using Deep Neural Networks (DNN) and Sentinel-3 satellite data. Findings show that grasslands contributed the most to overall SOC stocks (31.36 %), while urban vegetation contributed the least (0.04%). Results also show that commercial (46.06 t/h) and natural (44.34 t/h) forests had better carbon sequestration capacity than other classes. These findings provide an important guideline for managing SOC stocks in South Africa, useful in climate change mitigation by promoting sustainable land-use practices. The fifth objective sought to determine the distribution of SOC within South Africa’s major biomes using remotely sensed-topo-climatic data and Concrete Autoencoder-Deep Neural Networks (CAE-DNN). Findings show that the CAE-DNN model (built from 26 selected variables) had the best accuracy of the DNNs examined, with an RMSE of 7.91 t/h. Soil organic carbon stock was also shown to be related to biome coverage, with the grassland (32.38%) and savanna (31.28%) biomes contributing the most to the overall SOC pool in South Africa. forests (44.12 t/h) and the Indian ocean coastal belt (43.05 t/h) biomes, despite having smaller footprints, have the highest SOC sequestration capacity. To increase SOC storage, it is recommended that degraded biomes be restored; however, a balance must be maintained between carbon sequestration capability, biodiversity health, and adequate provision of ecosystem services. The sixth objective sought to project the present SOC stocks in South Africa into the future (i.e. 2050). Soil organic carbon variations generated by projected climate change and land cover were mapped and analysed using a digital soil mapping (DSM) technique combined with space-for-time substitution (SFTS) procedures over South Africa through 2050. The potential SOC stocks variations across South Africa's major land uses were also assessed from current (2021) to future (2050). The first part of the study uses a Deep Neural Network (DNN) to estimate current SOC content (2021), while the second phase uses an average of five WorldClim General Circulation Models to project SOC to the future (2050) under four Shared Socio-economic Pathways (SSPs). Results show a general decline in projected future SOC stocks by 2050, ranging from 4.97 to 5.38 Pg, compared to estimated current stocks of 5.64 Pg. The findings are critical for government and policymakers in assessing the efficacy of current management systems in South Africa. Overall, this study provides a cost-effective framework for national scale mapping of SOC stocks, which is the largest terrestrial carbon pool using advanced DL-based remote sensing approach. These findings are valuable for designing appropriate management strategies to promote carbon uptake, soil quality, and measuring terrestrial ecosystem responses and feedbacks to climate change. This study is also the first DL-based remote sensing of SOC stocks distribution in South Africa. Iqoqa Ikhabhoni yomhlabathi engaguquliwe, phecelezi i-soil organic carbon (SOC) ibaluleke kakhulu ebudlelwaneni bezinto eziphilayo nendawo eziphila kuyona futhi isiza ukuqonda kabanzi ubudlelwane bamakhabhoni nezinto eziyidingayo, nokuthi lokho kunayiphi imiphumela. Nokho, ukungcola okungajwayelekile okudalwa ngabantu kubonakala kuza noshintsho olukhulu ekuhanjisweni kwe-SOC kuwona wonke umhlaba, okuholela ekutheni kube nokulahleka kwekhabhoni eningi. Ukwengeza, ukuhlawumbisela okuthembekile nge-SOC, ikakhulukazi okuthinta umthamo omkhulu kubonakala kuqhubeka nokuba yinkinga ngenxa yesizathu sokuthi kukhona izibonelo zayo ezimbalwa, kanti nezinga elihle liyagqoza, nendlela eyiyo okumele ilandelwe ukukala. Indlela yokuhlola buqamama, phecelezi i-Remote sensing (RS) iyona ebonakala njengendlela engalandelwa ukuhlola iSOC ensimini noma egunjini lokuhlolela, ikakhulukazi uma kuthinta indawo enkulu. Nokho, ukuhlonza indlela ethembekile yokusatshalaliswa kwe-SOC kusetshenziswa imininingwane ye-RS kudinga izindlela eziseqophelweni eliphezulu zokuhlaziya. Ukuqhathanisa nendleya ye-linear ne-classical machine learning (ML), Indlela ye-deep learning (DL) yona ibonakala iletha ubungcono obukhulu ekuhlaziyeni imininingo ngenxa yokukwazi ukuhlonza izinto ezidingekalayo nokuveza izinto eziyinkinga kuleyo ndawo enemininingo eminingi. Ukuthuthuka kwendlela yokuhlola buqamama, ukuhlaziywa kwemininingo eminingi, nokufunda ngobuciko bokwakha indlela yokwenza, konke kuza namathuba amahle okuphaka uhlelo ngobuningi balo be-SOC. Nakuba kunjalo, kubonakala kunolwazi oluyingcosana emibhalweni yocwaningo mayelana nokusebenza kwezindlela zokuhlola buqamama ngesihlawumbiselo se-SOC. Kuze kube manje, lolu cwaningo beluhlose ukucubungula izindlela zokuhlaziya buqamama ze-DL ngokusatshalaliswa kwe-SOC eNingizimu-Afrikha yonkana. Inhloso yokuqala bekuwukunikeza ulwazi olufushane mayelana nendlela ejwayelekile yokusabalalisa, phecelezi i- traditional neural network (TNN) nendlela yokuhlaziya buqamama ye-DL ye-SOC ngokugcizelela ukubaluleka kwezinto ezijwayelekile, nomahluko. Okufanayo nezingqinamba, kanti inhloso yesibili inikeze ukucubungula okujulile komlando, ukusetshenziswa kwento, izinselelo, kanye namathuba okusebenza kwendlela yokuhlaziya buqamama ye-DL ekusabalaliseni i-SOC. Ukuhlaziya ngokwekhwalithethivu ekusebenziseni i-TNN ne-DL nakho kwenziwa. Imiphumela iveza ukuthi imibhalo eminingi yocwaningo yashicilelwa eNyakatho nomhlaba kanti lapha e-Afrika khona kwashicilelwa emine nje kuphela. Imiphumela iphinde iveze ukuthi ucwaningo oluningi lulandela indlela ebheka imininingo ehlanngene, ikakhulukazi ukubheka imibala eminingi yokukhanya, uma kuqhathaniswa nengxubevange yemininingo. Ukuqhathanisa nezindlela ze-DL (10%) ne-TNN (90%) yizona ezithandwa kakhulu emibhalweni yocwaningo, kodwa, indlela ye-DL ikhiqize okuneqinso (93%) kunendlela ye-TNN (85%). Ukucubungula kuphetha ngokugqamisa amathuba azayo okuthola ulwazi lwe-SOC kusetshenziswa indlela yokuhlola buqamama nge-DL. Inhloso yesithathu yona yayiqhathanisa ukuthembeka kwe-DL-deep neural network (DNN) kanye ne-TNN—artificial neural network (ANN), kanye nenye indlela endala edumile ye-ML efaka phakathi i-random forest (RF) kanye ne-support vector machine (SVM), ukhubheka isikalo sikazwelonke se-SOC kusetshenziswa imininingo ye-Sentinel-3. Nge-root mean square error (RMSE) ye-10.35 t/ha, indlela ye-DNN yakhiqiza imiphumela emihle kakhulu, ilandelwa yi-RF (11.2 t/ha), i-ANN (11.6 t/ha), ne-SVM (13.6 t/ha). Amandla okuhlaziya e-DNN, ehlanganiswe namandla okukwazi ukubhekana nemininingo eminingi kakhulu yikhona okwenza ibaluleke ukwedlula indlela ye-ML. Emva kokuhlonza amandla e-DL phezu kwawe-TNN kanye nezinye izindlela ezaziwayo, inhloso yesine yona ibigxile ekuhloleni ukusabalaliswa kwe-SOC ekusetshenzisweni komhlaba ngobuningi bawo lapha eNingizimu-Afrika, kusetshenziswa i-Deep Neural Networks (DNN) ne-Sentinel-3 satellite data. Imiphumela iveza ukuthi indawo enotshani iyona eletha izibalo eziphezulu ze-SOC sekuhlangene yonke into (31.36 %), kanti izimilo zasedolobheni zona zaletha izibalo ezincane (0.04%). Imiphumela iphinde ikhombise ukuthi amahlathi atshalelwe ukudayisa (46.06 t/h) kanye nawemvelo (44.34 t/h) ayekhombisa ukuba nekhabhoni enhle uma kuqhathaniswa namanye. Le miphumela ingumhlahlandlela obalulekile mayelana nokugcinwa kwe-SOC lapha eNingizimu-Afrikha, okuyinto ebaluleke kakhulu ukubhekana nokuguquguquka kwesimo sezulu ngokugqugquzela izindlela eziyizo zokusebenzisa umhlaba. Inhloso yesihlanu yona ibihlose ukuthola ulwazi ngokusatshalaliswa kwe-SOC ezinhlakeni ezahlukene zomphakathi lapha eNingizimu-Afrikha kusetshenziswa indlela yokuhlaziya buqama kanye ne-Concrete Autoencoder-Deep Neural Networks (CAE-DNN). Imiphumela iveza ukuthi indlela ye-CAE-DNN (eyakhiwe ngezinto ezikhethiweyo ezingama-26) yakhombisa ubuqiniso obukhulu be-DNNs, eyayihloliwe, nge-RMSE of 7.91 t/h. I-SOC yaphinde yakhombisa ukuba nobudlelwane nokusabalala kohlaza olumilile, kukhona indawo enotshani (32.38%) nendawo engenazihlahla yohlaza lotshani (31.28%) okuyiyona ephethe umhlaba omningi uma usuhlanganisiwe we-SOC lapha eNingizimu-Afrikha, amahlathi (44.12 t/h) kanye nomhlaba onohlaza lotshani ukugudla ulwandle i Indian Ocean (43.05 t/h), ngale okubonakala kancane, kodwa inokugcwala okuningi kwe-SOC. Ukukhulisa indawo yokugcina i-SOC, kuphakanyiswa ukuba indawo yohlaza lotshani ebisagciniwe iphinde isetshenziswe; nokho-ke, kumele kube khona ukulinganisa okuyikhona phakathi kokuthathwa kwekhabhoni, impilo yokubhekwayo kanye nokunakekelwa kwezinto eziphilayo nendawo eziphila kuyona. Inhloso yesithupha yayihlose ukuvikela ukukhiqizwa kwe-SOC lapha eNingizimu-Afrikha ngisho eminyakeni eminingi ezayo (okuwunyaka wezi-2050). Izinhlobo ezahlukene ze-SOC ezikhiqizwe ngokuguquguquka okwahlukene kwezimo zezulu nomhlaba kwakahlwa futhi kwahlaziywa kusetshenziswa isu le-digital soil mapping (DSM) lihlanganiswe nezindlela ze-space-for-time substitution (SFTS) eNingizimu-Afrikha kuze kube unyaka wezi-2050. Abasebenzisi bakusasa bomhlaba okhiqiza izinhlobo ezahlukene ze-SOC nabo bahlolwa kusukela kwabamanje (2021) kuye kwabangomuso (2050). Ingxenye yokuqala yalolu cwaningo isebenzisa i-Deep Neural Network (DNN) ukugagula isimo ngqo sengqikithi ye-SOC (2021), kanti ingxenye yesibili yona isebenzisa okungenani izindlela ezinhlanu zokusabalalisa nge-WorldClim General Circulation kumaphrojekthi e-SOC nangeminyaka ezayo (2050) ngaphansi kwe-Shared Socio-economic Pathways (SSPs) emine. Imiphumela iveza ukwehla kwe-SOC ngokwezibalo zangomuso ngeminyaka yezi-2050, kusukela ku-4.97 kuya ku-5.38 Pg, uma kuqhathaniswa ne-SOC ekhona manje engu-5.64 Pg. Le miphumela ibaluleke kakhulu kuhulumeni nakulaba abakhipha izinqubomgomo ukubheka ukusebenza kahle kwezinhlaka zokuphatha eNingizimu-Afrikha. Sekukonke, lolu cwaningo lunikeza indlela yokucabanga nokwenza engabizi neyimpumelelo yokusabalalisa i-SOC, okuyiyona enkulu kakhulu ekukhiqizweni kwekhaboni kusetshenziswa indlela yokuhlola buqamama ye-DL. Lolu cwaningo lubalulekile ukuqhamuka nezindlela ezintsha zokuphatha ukuze kugqugquzeleke ukukhiqizwa kwekhabhoni, umhlaba ovundile, nokukala izinto eziphilayo nendawo eziphila kuyona kanye nokunikeza impendulo mayelana nokuguquguquka kwesimo sezulu. Lolu cwaningo lungolokuqala ngqa lokubheka indlela yokuhlaziya buqamama nge-DL lapha eNingizimu Afrikha.

Browse

Browsing Environmental Science by Title