The Little Karoo, situated in the Succulent Karoo biome of South Africa, has been heavily transformed by land use, and only 8.6% of the remaining natural vegetation is considered to be intact. There is ample evidence that the main cause of degradation is the overstocking of ostriches, an industry that has been the major economic driver of the area for more than 150 years. The ostrich stocking rate currently recommended is 22 ha.ostrich⁻¹. A literature review was used to examine the evidence, assumptions and rationale on which recommended and actually implemented stocking rates for ostriches are based. No experimental evidence using ostriches was found that supported the recommended stocking rate as either ecologically or economically sustainable. From the literature, there appears to be a wide gap between what are considered to be economically and ecologically sustainable stocking rates, with the implication that these two aims may be impossible to reconcile when practicing ostrich farming on natural veld. A comparison of recommended with actual stocking rates among land managers in the Little Karoo showed that all land managers far exceeded the recommended agricultural stocking rate of 22.8 ha.ostrich⁻¹. However, the stocking rates reported by land managers to the South African Ostrich Business Chamber were found to accurately reflect actual numbers determined when whole flocks had to be slaughtered after an outbreak of avian influenza. The recommended stocking rate appeared to be irrelevant to ostrich flock breeders and there appeared to be a trade-off between profitable ostrich farming and sustainable land-use practices. This study also investigated the attitudes and behaviour of ostrich farmers. It was found that environmental attitude is most likely the most important characteristic of a land manager to ensure positive conservation behaviour. This characteristic was most prominent in younger land managers with larger farms. The last component of the study integrated the context and complexity of the long term social, economic and ecological sustainability of this industry through the development of a logic model. The results showed a general lack of linkages between industry elements which impact on achieving sustainability targets. Greater collaboration between industry role-players, organized agriculture and conservation organizations is required to find a balance between utilization and conservation in the ostrich industry.

Land degradation is a great threat to the Beshlo Catchment in Blue Nile Basisn, not merely as an environmental issue, but also a social and economic problem. In Gedalas Watershed (one of the micro catchments of Beshelo), land degradation, mediated by both biophysical and socio-economic drivers, is among the major environmental sustainability and social-economic development threats in the area. The threat is manifested in depletion of natural vegetations, water, soil and other natural resources; disruption of ecosystem functions, processes, integrity, and services. Given its particular vulnerability, watershed management activities have been in operation since the mid-1970s. Recently, the idea of Sustainable land management through integrated watershed development program has been initiated with the objective of reducing land degradation risks and ensuring food security at both the nationwide and family circle. Despite these investments and efforts, real evidences of success and failures of such efforts were not satisfactory explored. The objectives of this study were, therefore, to analyze the existing status and future prospects of sustainable land management and evaluates its implication on the environmental integrities and the local livelihoods specific to Gedalas watershed. For this effect, the study investigated the dynamics, deriving forces and implications of LULC, soil erosion and soil fertility status of the watershed, current status of watershed management practices, pertinent challenges and opportunities for practicing land management technologies and approaches that might help meet the sustainability requirements of SLM practices. In addition, the study explored factors that determine the willingness of farming households to undertake SLM practice. As the study carried in the coupled human-environment system of rural landscapes, interdisciplinary geographical approaches which integrats social and natural science methodologies were employed to deal with issues of land degradation-and-rehabilitation status comprehensively. The general findings of the study show that though it would be dificult to measure all the composite aspects of land degradation, some of the parameters considered in this study revealed that land degradation is a perpetuating challenge in the watershed. It is evidenced from the overall undesirable land use/cover changes i.e transition of 21.25% of Afro/sub alpine landscapes, 17.59% of the grasslands and 8% of shrub lands to either to cultivated land or settlement areas over the 1973–2017 period, which have unintended negative socio-ecological repercussions on the watershed; high annual mean soil loss value (which range from 37t/ha/year average values to 393 t/ha/yr soil loss rates on water courses) that exceed threshold level and a wide gap between the need for SLM and the actual achievement of SLM practices,including limited adherence to the idea behind contemporary land management policies and implementation principles and approaches. The study further revealed the presence of opportunities as well as a myriad of challenges that need to be tackled in order to achieve sustainable land management goals. The study colcludes that, though, some encouraging progresses have been observed in the SLM project sites; land degradation has remained a problem in the watershed. This calls for strenuous efforts to promote and assist wide scale adoption of SLM practices that address the pervasive land degradation problem and achieve land degradation neutrality as highlighted in sustainable development goals. / Department of Geography / Ph. D. (Geography)

Economic development is one of the main objectives of developed and developing nations worldwide. Development comes with growth of urban areas. Urban growth is achieved through sand and gravel mining for construction of modern, attractive and durable structures. The study examined positive and negative environmental impacts of the continuous removal of river sand, pit sand and gravel from sampled rivers and open areas surrounding Gaborone developing Central Business District, malls and private properties in city. Quantitative and qualitative research designs that is questionnaire survey, oral interviews, field observation and measurements were used to collect data from selected sampled points. Metsimotlhabe and Ditlhakane rivers were selected because they are nearer to Gaborone and most river sand is mined from these rivers. More points were sampled from open areas in Kumakwane, Kopong and Bela Bela farms where pit sand and gravel are mined. Convenience and purposive sampling methods were used to pick questionnaire survey respondents (175) from Kumakwane and Metsimotlhabe villages where people affected lives. Findings of the study highlighted that river sand was mined most from rivers near Gaborone compared to pit sand and gravel because of its multi uses. Mining is important for economic development, to construct durable, modern structures, employment creation and revenue collection but removal of river sand leads to deepening and widening of rivers. Artificial rivulets are formed as resource is extracted uncontrollably. Pit sand and gravel are extracted from open areas creating uncovered deep pits, which caused of accidents to children and livestock. Erosion and environmental degradation occur due to continuous mining. Miners dispose waste on open areas and riverbeds causing land pollution. Dust and noise pollution from tipper trucks ferrying sand and gravel are a cause of concern to villagers as the trucks move even at night, disturbing sleep. Solutions to uncontrolled mining include 24 hour security and regular raids on illegal miners. The author recommends that heavy penalties should be imposed to curb illegal mining. High level decision making forum involving all stakeholders is necessary to discuss problems of illegal mining and how to limit negative impacts. Department of Mines need to develop an Environmental Management Plan and a close monitoring program nationwide. / Environmental Sciences / M. Sc. (Environmental Management)

Bodendegradation ist ein wachsendes Problem von Pakistan, die Biomasse Verlust verursacht und hat einen schlechten Einfluss auf die Wirtschaft des Landes. Nordöstlich von der Provinz Punjab, die berühmt für die Reisanbau ist, leidet auch mit diesem Problem. Zusammen mit einigen anderen Gründen, sind institutionelle Aufbau in den Regionen und der Landnutzungsänderungen der Hauptgründe für diesen Abbau. Obwohl das Land ist, die privaten Eigentümern, aber wegen der Störung der bestehenden Eigentumsrechte und die jüngste Stadterweiterung in der Region hat interfamiliären Konflikte zwischen Grundbesitzern im Zusammenhang mit Entfremdung Land provoziert. Diese Konflikte haben ein Potenzial von gefährden ländlichen Setup und der landwirtschaftlichen Produktion des Landes. Das Ziel der Studie ist es, diese Konflikte Ansatz, den Schwerpunkt auf die Notwendigkeit des institutionellen Wandels für die Nutzung von landwirtschaftlichen degradierten Flächen und mögliche Governance-Struktur für Land Umwandlung in Pakistan. Die Organe der Sustainability Framework von Hagedorn et al (2002) wird verwendet werden, und einige politische Empfehlungen gehen abgeleitet werden. / Land degradation is a growing problem of Pakistan, which causes biomass loss and has a bad effect on the economy of the country. Northeast of Punjab province, which is famous for the rice cultivation, is also suffering with this problem. Along with some other reasons, institutional setup in the regions and the land-use change are the main reasons of this degradation. Although the land is owned by private owners, but because of the malfunctioning of existing property rights and the recent urban expansion in region has provoked interfamily conflicts between landowners related to land alienation. These conflicts have a potential of jeopardising rural setup and agriculture production of the country. The aim of the study is to approach these conflicts, focus on the need of institutional change for the use of agricultural degraded lands and possible governance structure for land conversion in Pakistan. The Institutions of Sustainability Framework of Hagedorn et al (2002) will be employed and some policy recommendations are going to be derived

Made available in DSpace on 2016-04-28T14:56:17Z (GMT). No. of bitstreams: 1 2009 - Priscila Nogueira Matos.pdf: 1723305 bytes, checksum: 89e42c980c370e9eec2db3e9b08306ae (MD5) Previous issue date: 2009-03-31 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The Mining is considered the activity can cause a great impact in the environment, involving the vegetation and subsoil layers remove. After the finish of mineral sources, mandatorily these areas require recovery measures. This study aimed to evaluate the initial establishment of three genotypes of palm oil: C2501, C2301 and C2528, indicated by Embrapa Amaz?nia ocidental, in area of mining in the northwest Par?. Was also evaluated the soil fauna, the occurrence of nitrogen fixing bacteria and arbuscular mycorrhizal fungi associated with culture. The establishment of culture was evaluated for survival, height, number of leaves and nutritional status of plants and soil fertility. The impact on soil fauna was evaluated with samples in the experimental area and in areas of reforestation and forest adjacent to it. To determine the presence of mycorrhizal fungi and diazotrophic bacteria samples were taken from roots and soil in the palm oil. The amount of the plant N derived from BNF was determined with the natural abundance of 15N technique. The mortality of the plants was low, but growth was not strong, this may be related to low P in soil and periods of drought. In this initial stage of establishing the symbiosis with diazotrophic bacteria was inefficient where only the genotypes C2501 and C2528 were 4,5 and 4,8% respectively of N derived from BNF, with great variability in the population of bacteria. The mycorrhizal fungi no showed differences in sampled areas and this result may be related to water deficit and sampling period in the dry season. The composition of soil fauna not differ in the areas of palm oil plantation with and without green manure, and conventional reforestation, however not present the same diversity of the forest. / A minera??o ? considerada uma atividade econ?mica que causa um grande impacto ao ambiente, envolvendo a retirada da vegeta??o e camadas do subsolo. Ap?s a exaust?o dos recursos minerais, estas ?reas necessitam obrigatoriamente de medidas de recupera??o. O objetivo deste trabalho foi avaliar o estabelecimento inicial de tr?s gen?tipos de dend?: C2501, C2301 e C2528, indicados pela Embrapa Amaz?nia Ocidental, em ?reas de est?ril da Minera??o de bauxita no noroeste do Par?. Foram avaliados tamb?m a fauna do solo, a ocorr?ncia de bact?rias fixadoras de nitrog?nio e fungos micorr?zicos arbusculares associados ? cultura. O estabelecimento da cultura foi avaliado pela sobreviv?ncia, altura, n?mero de folhas e estado nutricional das plantas, e a fertilidade do solo. O impacto na fauna do solo foi avaliado na ?rea experimental e em ?reas de floresta prim?ria e reflorestamento adjacentes a este. A presen?a de bact?rias diazotr?ficas e fungos micorr?zicos foram determinadas em amostras de ra?zes e solo na ?rea do dend?. A quantidade de N na planta derivado da FBN foi determinada pela t?cnica de abund?ncia natural de 15N. A mortalidade das plantas foi considerada baixa apesar de seu crescimento n?o ter sido vigoroso podendo este estar relacionado ao baixo teor de P no solo e aos per?odos de stress h?drico por falta de ?gua. Neste est?gio inicial de implanta??o a simbiose com bact?rias diazotr?ficas foi pouco eficiente onde apenas os gen?tipos C2501 e C2528 tiveram 4,5 e 4,8% respectivamente de N derivado da FBN, com grande variabilidade na popula??o de bact?rias. Os fungos micorr?zicos n?o apresentaram diferen?as nas ?reas analisadas, tal resultado pode estar relacionado com a defici?ncia h?drica e o per?odo de coleta na ?poca seca. A composi??o da fauna do solo nas ?reas de plantio de dend? com e sem aduba??o n?o diferiram entre si e em rela??o ao reflorestamento convencional, n?o apresentando, entretanto a mesma diversidade da floresta prim?ria.

Thesis (M.Sc. (Geography)) --University of Limpopo, 2018 / Soil erosion, which is a critical component of land degradation, is one of the serious global environmental problems often threatening food security, water resources, and biodiversity. A comprehensive assessment and analysis of remote sensing applications in the spatial soil erosion mapping and monitoring over time and space is therefore, important for providing effective management and rehabilitation approaches at local, national and regional scales. The overall aim of the study was to assess the use of multispectral remote sensing sensors in mapping and monitoring the spatio-temporal variations in levels of soil erosion in the former homelands of Sekhukhune district, South Africa. Firstly, the effectiveness of the new and freely available moderate-resolution multispectral remote sensing data (Landsat 8 Operation Land Imager: OLI and Sentinel-2 Multi-Spectral Instrument: MSI) derived spectral bands, vegetation indices, and a combination of spectral bands and vegetation indices in mapping the spatio-temporal variation of soil erosion in the former homelands of Sekhukhune District, South Africa is compared. The study further determines the most optimal individual sensor variables that can accurately map soil erosion. The results showed that the integration of spectral bands and spectral vegetation indices yielded high soil erosion overall classification accuracies for both sensors. Sentinel-2 data produced an OA of 83, 81% whereas Landsat 8 has an OA of 82.86%. The study further established that Sentinel-2 MSI bands located in the NIR (0.785-0.900 μm), red edge (0.698-0.785μm) and SWIR (1.565-2.280 μm) regions were the most optimal for discriminating degraded soils from other land cover types. For Landsat 8 OLI, only the SWIR (1.560-2.300 μm), NIR (0.845-0.885 μm) region were selected as the best regions. Of the eighteen spectral vegetation indices computed, Normalized Difference Vegetation Index (NDVI) and Soil Adjusted Vegetation Index (SAVI) and Global Environmental Monitoring Index (GEMI) were selected as the most suitable for detecting and mapping soil erosion. Secondly, the study assessed soil erosion in the former homelands of Sekhukhune, South Africa by applying a time-series analysis (2002 and 2017), to track changes of areas affected by varying degrees of erosion. Specifically, the study assessed and mapped changes of eroded areas (wet and dry season), using multi-date Landsat products 8 OLI and 7 Enhanced Thematic Mapper (ETM+)). Additionally, the study used extracted eroded areas and overlay analysis was performed together with geology, slope and the Topographic Wetness Index (TWI) of the area under study to assess whether and to what extent the observed erosional trends can be explained. ii Time series analysis indicated that the dry season of 2002, experienced 16.61 % (224733 ha) of erosion whereas in 2017 19.71% was observed. A similar trend was also observed in the wet season. This work also indicates that the dominant geology type Lebowa granite: and Rustenburg layered its lithology strata experienced more erosional disturbances than other geological types. Slopes between 2-5% (Nearly level) experienced more erosion and vice-versa. On the hand, the relationship between TWI and eroded areas showed that much erosion occurred between 3 and 6 TWI values in all the seasons for the two different years, however, the dry season of 2002 had a slightly higher relationship and vice-versa. We, therefore, recommend use and integration of freely and readily available new and free generation broadband sensors, such as Landsat data and environmental variables if soil erosion has to be well documented for purposes of effective soil rehabilitation and conservation. Keywords: Food security Global changes, Land degradation, Land-based ecosystems, Land management practices, Satellite data, Soil conservation, Sustainable Development; Topographic Wetness Index; Time series analysis.

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The degradation of rangeland grass is currently one of the most serious environmental problems in South Africa. Increaser and decreaser grass species have been used as indicators to evaluate rangeland condition. Therefore, classifying these species and monitoring their relative abundance is an important step for sustainable rangelands management. Traditional methods (e.g. wheel point technique) have been used in classifying increaser and decreaser species over small geographic areas. These methods are regarded as being costly and time-consuming, because grasslands usually cover large expanses that are situated in isolated and inaccessible areas. In this regard, remote sensing techniques offer a practical and economical means for quantifying rangeland degradation over large areas. Remote sensing is capable of providing rapid, relatively inexpensive, and near-real-time data that could be used for classifying and monitoring species. This study advocates the development of techniques based on remote sensing to classify four dominant increaser species associated with rangeland degradation namely: Hyparrhenia hirta, Eragrostis curvula, Sporobolus africanus and Aristida diffusa in Okhombe communal rangeland, KwaZulu-Natal, South Africa. To our knowledge, no attempt has yet been made to discriminate and characterize the landscape using these species as indicators of the different levels of rangeland degradation using remote sensing. The first part of the thesis reviewed the problem of rangeland degradation in South Africa, the use of remote sensing (multispectral and hyperspectral) and their challenges and opportunities in mapping rangeland degradation using different indicators. The concept of decreaser and increaser species and how it can be used to map rangeland degradation was discussed. The second part of this study focused on exploring the relationship between vegetation species (increaser and decreaser species) and different levels of rangeland degradation. Results showed that, there is significant relationship between the abundance and distribution of different vegetation species and rangeland condition. The third part of the study aimed to investigate the potential use of hyperspectral remote sensing in discriminating between four increaser species using the raw field spectroscopy data and discriminant analysis as a classifier. The results indicate that the spectroscopic approach used in this study has a strong potential to discriminate among increaser species. These positive results prompted the need to scale up the method to airborne remote sensing data characteristics for the purpose of possible mapping of rangeland species as indicators of degradation. We investigated whether canopy reflectance spectra resampled to AISA Eagle resolution and random forest as a classification algorithm could discriminate between four increaser species. Results showed that hyperspectral data assessed with the random forest algorithm has the potential to accurately discriminate species with best overall accuracy. Knowledge on reduced key wavelength regions and spectral band combinations for successful discrimination of increaser species was obtained. These wavelengths were evaluated using the new WorldView imagery containing unique and strategically positioned band settings. The study demonstrated the potential of WorldView-2 bands in classifying grass at species level with an overall accuracy of 82% which is only 5% less than an overall accuracy achieved by AISA Eagle hyperspectral data. Overall, the study has demonstrated the potential of remote sensing techniques to classify different increaser species representing levels of rangeland degradation. In this regard, we expect that the results of this study can be used to support up-to-date monitoring system for sustainable rangeland management. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

[Truncated abstract] Land clearing is known to increase runoff, and in many dryland landscapes is also associated with rising saline watertables, causing increased stream salinity and degrading riparian vegetation. The limited understanding of how river morphology responds to these changes and the potential for vegetation-based strategies to offer river management options under these conditions, has prompted this research. In southwestern Australia the severity of salinity and recent nature of land clearing provides an appropriate setting to investigate river response. A data-based, multidisciplinary methodology was applied to determine how land clearing and landscape salinisation has altered landscape sensitivity through changes in erosive potential, system connectivity and material threshold mechanisms, and how these affect patterns of river response. The study investigated the responses of morphologically similar reaches across fifty two study sites in the Kent River and Dalyup River catchments, in the south coastal rivers region of Western Australia. Land clearing was found to have significantly altered the hydrologic regime and erosive potential in both frequency and magnitude, with flow becoming more perennial, and increased annual discharge, flood peaks and bankfull flow frequency. While sediment transport rates have also increased since land clearing, they remain low on a global scale. Human response to a reduced rainfall regime and related water security pressures has caused large hillslope areas to be decoupled from the main channels by bank and farm dam construction, and have reduced downstream transmission of change. ... By contrast, steeper-sloped mid-catchment areas with minimal vegetation degradation caused by salinity are associated with higher erosive potential. A more erosive response is observed in these reaches where floodplains have been cleared for agricultural purposes. A conceptual model of vegetation growth across the salinity gradient observed in the study catchments was developed, and applied to selected river styles to assess the potential that vegetation-based strategies offer for river management. This work identifies the unsuitability of river restoration strategies, but the potential for river restoration or remediation in a saline landscape. Hydraulic modelling demonstrated that river rehabilitation strategies such as improving the vegetation condition of the riparian buffer using native or commercial species on areas elevated above saline flow can stabilise reaches. For river styles in wide and flat valleys, there is limited potential for vegetation-based river rehabilitation under the current salinity gradient. Field observation and modelling suggest that river remediation may offer geomorphic management options in salt-affected reaches through channelisation to lower watertables, and further research on this is warranted. This work found a consistent response for river styles across the two study catchments. Based on the understanding of river response and the potential for vegetation-based river management for each style, this research offers a regional-scale tool for river management in a saline landscape.