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Accueil du site → Doctorat → Allemagne → 2018 → Peatlands in Maputaland : Genesis, substrates and properties exemplified by the region of “Greater Manguzi”

Humboldt-Universität zu Berlin (2018)

Peatlands in Maputaland : Genesis, substrates and properties exemplified by the region of “Greater Manguzi”

Gabriel, Marvin

Titre : Peatlands in Maputaland : Genesis, substrates and properties exemplified by the region of “Greater Manguzi”

Auteur : Gabriel, Marvin

Université de soutenance : Humboldt-Universität zu Berlin

Grade : Doctor rerum agriculturarum (Dr. rer. agr.) 2018

Résumé
Peatlands in South Africa are important and threatened ecosystems. They are of great socio-ecological significance, as sources of freshwater, fertile land, material for construction, medicinal plants, habitat for specialised plants and animals, and as an attraction for ecotourists. Some 20.200 ha, about two thirds of South Africa’s peatlands, are located at the Maputaland Coastal Plain. Eucalyptus plantations and common cultivation practices which include drainage are threatening the existence of the peatlands. This dissertation investigates peatland formation in Maputaland from a soil-related point of view, in order to identify the requirements for effective conservation and restoration measures, as well as more sustainable cultivation practices. Insights into peat formation processes were obtained through a macrofossil analysis. Based on the field examination of 141 soil profiles, 15 different peatland substrates were described and categorised into genetic substrate groups, and botanical peat types. Mean values for the following physical and chemical properties were determined for each substrate : Carbon content, C/N ratio, electrical conductivity, pH-value, bulk density, pore size distribution, saturated hydraulic conductivity, unsaturated hydraulic conductivity and maximum capillary rise. Moreover, the effect of degradation on the physical and chemical properties of South African peatlands was explored. Therefore, the aforementioned properties were measured for substrates at different degrees of degradation. Based on the changes in the soil properties thus established, the loss of ecosystem functions through degradation is discussed. By considering the frequency of occurrence of the substrate types in different hydrogeomorphic peatland types, adapted implications for conservation, restoration and cultivation are derived. In addition, based on the actual projections of climate change, estimations about future stress on the peatlands were derived.

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