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University of Cape Town (2012)

Trends in vegetation productivity and seasonality for Namaqualand, South Africa between 1986 and 2011 : an approach combining remote sensing and repeat photography

Davis Claire

Titre : Trends in vegetation productivity and seasonality for Namaqualand, South Africa between 1986 and 2011 : an approach combining remote sensing and repeat photography

Auteur : Davis Claire

Université de soutenance : University of Cape Town

Grade : Master of Science (2012)

Résumé
This thesis presents an assessment of vegetation change and its drivers across a subset of Namaqualand, South Africa. Namaqualand forms part of the Succulent Karoo biome, which is characterised by exceptionally high species biodiversity but which has undergone severe transformation since the arrival of pastoral colonists. Vegetation productivity in Namaqualand is of great importance since there is a high dependence on natural resources, livestock and agriculture for both subsistence and income. However, there is considerable debate on the relative contribution of land-use change and climate change to vegetation change and land degradation in Namaqualand. Early studies based on bioclimatic envelop models suggest that an increase in temperature and more arid conditions could result in the vegetation cover of the Succulent Karoo being significantly reduced. On the other hand, more recent studies show that less extreme changes in rainfall could result in the vegetation of the biome remaining fairly stable with possible increases in the spatial extent by 2050. Furthermore, field observations and repeat photography, suggest that the change in vegetation in the region over the course of the 20th century generally portrays an increase in cover largely as a result of changes in land-use. By combining repeat photography and satellite data from NOAA-AVHRR and TERRA-MODIS sensors as well as baseline climatology data from the CRU TS 3.2 data set this study aimed to : (1) Determine the critical pathways of inter-annual and intra-seasonal vegetation change in the Namaqualand ; (2) Investigate the role of land-use and climate variability as key drivers of vegetation change in Namaqualand

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Page publiée le 1er octobre 2014, mise à jour le 26 mai 2018