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En cette époque de profonds bouleversements environnementaux, les motifs invoqués par la communauté internationale en vue de protéger la nature sont multiples. Si la préservation de la biodiversité est souvent mise à l’avant-plan, les préoccupations témoignent également d’une sensibilité omniprésente à la beauté des paysages. Cette thèse étudie donc le rôle de l’appréciation esthétique de la nature dans la désignation internationale d’aires protégées. Elle emploie pour cela l’exemple de la Convention concernant la protection du patrimoine mondial, culturel et naturel, adoptée en 1972 par l’UNESCO. Les préceptes de cet instrument de conservation de portée globale admettent l’importance de sauvegarder la beauté du monde naturel, sans toutefois prescrire de moyens clairs pour identifier et sélectionner les sites méritant protection à ce titre. Face à ce flou méthodologique, la thèse examine les facteurs historiques, structurels et techniques qui façonnent, de façon relativement implicite et spontanée, l’inscription d’aires naturelles d’une beauté exceptionnelle sur la Liste du patrimoine mondial. La thèse est constituée de six chapitres. Le premier chapitre introduit le problème et la question de recherche. La revue de la littérature pose ensuite les bases contextuelles et théoriques de la recherche en explorant différents facteurs historiques et philosophiques d’appréciation de la nature. Le troisième chapitre expose la méthodologie qualitative et historique employée dans la thèse. Il est suivi d’un chapitre qui retrace l’origine des préoccupations esthétiques qui ont été intégrées à la Convention du patrimoine mondial lors de sa création, avant de détailler le développement et l’application de ces idées durant les cinq décennies de sa mise en œuvre. Le cinquième chapitre est quant à lui dédié à l’étude spécifique de l’application du critère de sélection (vii), qui prévoit la reconnaissance « […] d’aires d'une beauté naturelle et d'une importance esthétique exceptionnelles ». Finalement, la conclusion renferme une synthèse et une discussion des résultats, appelant à une reconsidération de la valeur esthétique de la nature à travers une meilleure prise en compte de ses dimensions humaine et sociale. Elle aborde également la contribution et les limites de la thèse et suggère des pistes de recherches ultérieures. Les résultats de la recherche brossent un portrait précis des enjeux théoriques et pratiques qui caractérisent l’interprétation de la valeur esthétique des espaces naturels dans le cadre du patrimoine mondial. Celle-ci s’avère largement influencée par la séparation conceptuelle et disciplinaire entre culture et nature ainsi que par le paradigme scientifique, objectiviste et universaliste qui prédominent au sein de la Convention de 1972. Réalisée sans assise théorique claire, l’évaluation de la beauté naturelle est vulnérable aux jugements subjectifs et aux incohérences. Pour y conférer plus de structure et de rigueur, la thèse appelle à une meilleure prise en compte du rôle de la perspective humaine et des facteurs socioculturels dans la construction de la valeur esthétique de la nature. / In this era of substantial environmental disruption, incentives given by the international community to protect nature are many. While the preservation of biodiversity is often at the forefront, preoccupations also show an enduring sensitivity to scenic beauty. This thesis therefore examines the role of the aesthetic appreciation of nature in the international designation of protected areas, through the example of the 1972 UNESCO Convention concerning the Protection of the World Cultural and Natural Heritage. The principles of this global conservation instrument recognize the importance of safeguarding the beauty of the natural world, but do not prescribe clear means for identifying and selecting sites deserving protection as such. In the face of this methodological uncertainty, this thesis examines the historical, structural, and technical factors that shape, in a relatively implicit and spontaneous way, the inscription of natural areas of outstanding beauty on the World Heritage List. The thesis consists of six chapters. The first chapter introduces the problem and research question. The literature review then sets the contextual and theoretical basis for the research by exploring various historical and philosophical factors of nature appreciation. The third chapter outlines the qualitative and historical methodology used in the thesis. This is followed by a chapter tracing the origin of the aesthetic concerns that were incorporated into the World Heritage Convention at its inception, before detailing the development and application of these ideas over the five decades of its implementation. The fifth chapter is dedicated to the specific study of the application of selection criterion (vii), which provides for the designation of "...areas of outstanding natural beauty and aesthetic importance". Finally, the conclusion contains a synthesis and discussion of the results, calling for a rethinking of the aesthetic value of nature through a better consideration of its human and social dimensions. It also addresses the contribution and limitations of the thesis, and suggests avenues for further research. The results of the research provide a clear picture of the theoretical and practical issues that characterize the interpretation of the aesthetic value of natural areas in the context of World Heritage. This interpretation is largely influenced by the conceptual and disciplinary separation between culture and nature, as well as by the scientific, objectivist and universalist paradigm that prevail in the 1972 Convention. Carried out without a clear theoretical foundation, the assessment of natural beauty is vulnerable to subjective judgments and inconsistencies. To provide more structure and rigor, this thesis calls for a better consideration of the role of the human perspective in constructing the aesthetic value of nature.

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Thesis (M.Sc. (Soil Science)) -- University of Limpopo, 2022 / In South Africa, land use planning has received limited attention in areas perceived as suitable for agricultural production. In the lack of reliable soil type and fertility status information, crop yields remain lower than the land’s potential, with subsequent land degradation. Despite this, studies that focused on land capability and soil suitability to date have not considered the spatial variability of the soil nutrients and factors influencing their variability. However, this information is key for site-specific soil management. Therefore, it is vital to link land capability and soi suitability with the spatial variability of soil nutrients as it opens opportunities for more rational management of the soil resources since soil nutrients directly affect crop growth and consequently yield. To address this issue, a study was conducted on a 12 ha banana plantation portion of the Makuleke farm. The main objectives of this study were to (1) survey, classify and characterise soils in order to derive and map land capability classes of Makuleke farm, (2) quantify the physical and chemical properties of the soils in order to derive and map the soil suitability of Makuleke farm for banana production, (3) assess the spatial variability and structure of soil nutrients across the Makuleke farm and (4) Identify the factors of control of the spatial variability of the soil nutrients across the Makuleke farm. To begin with, a field soil survey was conducted using transect walks complemented by auger observations to sub-divide the 12 ha banana plantation portion of the farm into varied soil mapping units. Thereafter, soil classification was done to group soils based on their morphological properties and pedological processes. During soil classification, a total of 12 representative profile pits (1.5 m × 1.5 m long × 2 m deep/limiting layer) were excavated, studied, described, and sampled. At each profile pit, three replicates samples were collected at 0 – 30 cm depth intervals giving rise to 36 bulk soil samples. From the gathered soil profile information, four soil units were thus delineated and identified across the 12 ha banana plantation. For soil fertility assessment, a grid sampling strategy at 50 × 50 m was adopted to collect the samples across the 12 ha banana plantation. A total of 27 composite samples were collected at the nodes of the grid, and thereafter bagged, labelled, and transported to the laboratory. In the laboratory, all collected samples were air-dried and sieved using a 2 mm sieve in preparation for soil physical and chemical properties analysis. The land capability assessment of Makuleke farm was done using the concepts and principles of the FAO framework for Land Evaluation (FAO, 1976), but adapted to South African conditions by Smith (2006). Soil suitability assessment was done using the FAO framework for Land Evaluation (FAO, 1976) coupled with the guidelines for rainfed agriculture (FAO, 1983) and the criteria proposed by Sys et al. (1993) and Naidu et al. (2006). To assess the spatial variability and structure of the soil nutrients across the farm, classical and geostatistical techniques were employed respectively. A correlation matrix was employed to identify key factors influencing the spatial variability of soil nutrients across the farm. For interpolation, ordinary kriging was used to generate soil nutrient spatial distribution maps. In this study, four soil forms were identified and classified as Hutton, Westleigh, Glenrosa, and Valsrivier, which are broadly distinguished as Lixisols, Plinthosols, Leptosols, and Cambisols. Land capability results revealed that 17% of the 12 ha portion of the farm has very high arable potential (I), 60% of the farm has medium arable potential (III), 6% has low arable potential (IV) and 17 % is non-arable (VI), which might explain the varied banana yields in the farm. Soil suitability analysis revealed that 12% of the 12 ha farm is highly suitable (S1), 34% is moderately suitable (S2), 38% is marginally suitable (S3) and 16% is permanently not suitable (N2) for banana production. The low arable and marginally suitable portion of the farm was under Valsrivier soils which were limited by its shallow depth, shallow rooting depth, acidic soil pH, low organic carbon (OC), and the fact that it was located on a steeper slope gradient. The non-arable and not suitable portion of the farm for banana production was under Glenrosa and it was limited by its location on a steep slope gradient and was characterised by shallow effective rooting depth, low OC, low clay content, and acidic soil pH. Classical statistical techniques revealed that phosphorus (P), potassium (K), calcium (Ca), zinc (Zn), manganese (Mn), and copper (Cu) content varied highly across the banana plantation, while magnesium (Mg) and total nitrogen (TN) varied moderately. In addition, the geostatistical analysis revealed that spatial dependency was weak (Ca, Cu, and TN), moderate (Mg and Zn), and strong (P, K, and Mn) for the different soil nutrients across the 12 ha banana plantation. Soil nutrients with strong spatial dependency have a good spatial structure and are easily manageable (in terms of fertilisation, liming, and irrigation) across the farm compared to the ones with weak spatial dependency which have a poor structure. This study also found that land attributes, which are soil type and topographic position were the main factors driving the spatial variability of the soil nutrients across the farm. In terms of soil type, soils such as Valsrivier and Glenrosa with 2:1 clay-type smectite were the ones that had nutrient content compared to soils with 1:1 clay-type kaolinite (e.g., Westleigh and Hutton). Higher nutrient contents were also observed in the footslope position compared to the middleslope of the farmland. Correlation analysis revealed that Mn was the key polyvalent cation influencing the spatial variability of P, K, and Zn. Soil pH and effective cation exchanges capacity (ECEC) were the key soil factors driving the spatial variability of Ca, while ECEC was the key factor affecting the spatial variability of Mg. Moreover, the spatial variability of soil Mn and Cu was driven by soil Cu and clay content, respectively. The kriged maps showed that P, Mg, Zn, and Mn were high in the northeast part and low in the northwest part of the farm. Similarly, K and Ca were low in the northwest part, but they were high in the south to the southwest part of the study area. Total nitrogen was high in the west part and low in the east-northeast part, while Cu was evenly distributed across the plantation. This study highlights the importance of prior land use planning (i.e., land capability and soil suitability) and fertility assessment for agricultural production. The research results obtained provide the actual reference state of the capability of the land for arable farming and soil suitability for banana production at Makuleke farm. Moreover, the research results provide the spatial variability and structure of the soil nutrients which have a greater impact on the growth and yield of bananas. The results obtained in this study will be useful for site-specific management of soil nutrients and other soil management practices (e.g., irrigation, fertilisation, liming, etc.), developing appropriate land use plans, and quantifying anthropogenic impacts on the soil system and thus improving land productivity. / National Research Foundation (NRF)

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