Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Food plants of Southern Africa

Auteur : Ruiters-Welcome, Ashton Kim

Université de soutenance : University of Johannesburg

Grade : PHILOSOPHIAE DOCTOR in BOTANY 2019

Résumé partiel
There have been many invaluable contributions to our knowledge of food plants of southern Africa, with the most comprehensive of these being the book Food from the veld by Fox and Norwood Young in 1982. This work is, however, not only outdated, it is also incomplete and not exclusively representative of the southern African flora. There is also no indication of how many of the southern African plant species are actually edible. Of all the literature available on the food plants of southern Africa, there are none that present the patterns of plant use and preferences in the region or in the language groups distributed within the region. There is also, therefore, no indication whether cross-cultural food plant selection in southern Africa is best explained by language ancestry, floristic environment or subsistence strategy. The availability of a comprehensive inventory of the food plants of southern Africa has value beyond the scope of ethnobotany, and can reveal many novel patterns within this subject. Seventy four literature sources (books, journal articles, checklists, grey literature and published ethnobotanical surveys) were used to compile an inventory and checklist of the food plants of southern Africa. This checklist was incorporated into an excel spreadsheet, listing all of the southern African species, made available by the South African National Biodiversity Institute (SANBI). Using this excel format, it was possible to determine many different patterns within families and genera as well as the popularity or importance of species. The checklist of edible plants has also been cross checked with the red data list to determine species of conservation concern. Patterns for the plant parts and food use categories were investigated for the region as well as for the different cultural groups. The functional food value of southern African edible plants was reviewed, and antioxidant as well as anthocyanin studies were undertaken on selected teas and edible fruits respectively. A literature review of the nutritional value of food plants was done and used to determine those species with high nutritional values as well as those species that have never been studied. The distribution of species with high values in certain nutrients were compared to those with lower values to determine distribution patterns for nutrients using distribution data provided by SANBI and ArcMap (GIS platform). Distribution data of southern African plants were also overlapped in ArcMap (GIS platform) with shape files (maps) of 19 language groups and eight biomes. Attribute tables extracted from ArcMap in the form of Excel spreadsheets, as well as regression analysis, were used to compare the diversity and selection of utilised vs edible vs all species within all southern African plant families. Five correlations were estimated between four pair-wise distance matrices (language ancestry, geographical proximity and floristic and edible environments) with Mantel tests using the ‘vegan’ package in R.

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