Natural and anthropogenic environmental variables pressures exert fitness pressures on our flora and vegetation and necessitate an understanding of the mechanisms of plant responses to those pressures. Overgrazing and desertification are examples of the stressors that affect plant community composition, on both large and small scales. In order to investigate the plant community response to these stressors it has been shown that it is more practical and informative to group plant species according to their functional characteristics into functional types than attempting to predict plant response solely based on previous range distribution data. The present study involved a survey of the dunefield vegetation of several privately owned farms as well as a communal farm in the southern Kalahari. The farms were subjectively chosen to represent a gradient from underutilized to overutilized. Plant community surveys were conducted on the farms and the dominant plant species were sampled and researched for selected functional traits to explore possible relationships between traits and grazing pressure. Ordination techniques were used to identify plant functional grazing response types. The identification of plant functional types through easy measurable traits will be a great aid in modelling and longterm environmental monitoring approaches. Of the three dunefield habitats, the dune street habitat was identified as the most vulnerable to overgrazing. A reduction in cumulative cover and an increase in bare surface cover indicated increased grazing pressure in the dune crest habitat. In the dune streets shrub cover and annual grass cover increased when veld was overgrazed. Functional analysis of 112 Kalahari plant species for a set of 47 plant traits showed that species clustering were strongly related to vegetative characteristics. The emerging clusters were strongly associated with major life forms, which comprised phanerophytes of different size classes, geophytes and herbaceous perennials, as well as herbaceous annuals. These clusters were identifiable even with the inclusion of reproductive traits. Selected vegetative traits are good indicators of plant response to land-use intensity since these traits lend competitive advantages to plant persistence under utilisation pressure. Plant height, spinescence, specific leaf area, leaf dry matter content, leaf sclerophylly and stem density were found to be examples of such traits. Phanerophyte and chamaephyte dominated functional groups were mostly associated with lower range condition and hemicryptophyte dominated groups with higher range condition, whereas herbaceous therophyte dominated groups did not show any specific association. / Dissertation (MSc)--University of Pretoria, 2011. / Plant Science / unrestricted

Please read the abstract in the section, 09summary, of this document / Thesis (PhD (Zoology))--University of Pretoria, 2008. / Zoology and Entomology / PhD / unrestricted

Thesis (MScConEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Previously, conservation activities were mainly focussed upon the establishment of protected areas that safeguarded and shielded the natural world from misuse, often resulting in the forced removal of indigenous communities. In South Africa, the ≠Khomani Bushmen, were one such group forcibly evicted from their homelands. Today, the community has regained access to their ancestral lands in the form of a land claim, settled in 1999, that awarded the community land rights in the form of six farms and land use rights within the now Kgalagadi Transfrontier Park (KTP). This gave them the right to use and manage their property falling within the park together with the conservation authority responsible for the Park, South African National Parks (SANParks). This study aims to improve our understanding of the use of resources by the ≠Khomani Bushmen. By obtaining insight on resource use and how knowledge of this use is transferred and shared, information on how to better involve and integrate the community in management processes is generated. The study identified the most important plants currently used within the ≠Khomani community and assessed this use. Additionally, social network analysis (SNA) was used to investigate how the social network structure depicts the distribution of knowledge which affects the community’s ability to manage their natural plant resources effectively. In an ethnobotanical survey, over 90 individuals were interviewed, using semi-structured interviews, on the farms awarded to the community. In total, 59 plant species from 28 families were found to be in use. Medicinal plants were most frequently cited (60%), with edible plants comprising a further 20%. Data was also collected on social relations surrounding the acquisition, generation and transfer of plant use knowledge. The knowledge networks all depict isolated individuals on the periphery and a few individuals loosely connected to central structures. This study demonstrates that wild plant use remains an important practice for the ≠Khomani people, primarily for medicinal purposes. It serves as baseline data on plant resources being used by the community and adds to our understanding of how traditional knowledge is being transmitted. The insight provided by SNA depicts the current distribution of knowledge and should be used by the community, as supported by network weavers and SANParks, to achieve their joint management goals. Network weaving can potentially counteract ecologically unsustainable practices, promoting collaboration and the transfer of traditional ecological knowledge. / AFRIKAANSE OPSOMMING: Voorheen was bewaringsaktiwiteite meestal gefokus op die vestiging van beskermde areas wat die natuurlike wêreld beveilig en beskerm het van misbruik wat dikwels die gevolg was van die geforseerde verwydering van inheemse gemeenskappe. In Suid-Afrika was die ≠Khomani Boesman groep een van die sodanige groepe wat op ʼn indrukwekkende manier van hulle tuislande uitgesit is. Vandag het die gemeenskap weer toegang gekry tot die land van hulle voorvaders in die indiening van ʼn grond eis wat in 1999 vasgestel is, en wat die gemeenskap grond regte toegeken het in die vorm van ses plase en grond regtelike gebruik binne die sogenoemde Kgalagadi Transfrontier Park (KTP). Dit het hulle die reg gegee tot die gebruik en bestuur van hulle eiendom wat binne die park val saam met die bewaringsowerhede wat verantwoordelik is vir die Park, Suid-Afrikaanse Nasionale Parke (SANParks). Die doel van hierdie studie is om ons begrip te verbeter van die gebruik van hulpbronne deur die ≠Khomani Boesman. Met die verkryging van insig oor hulpbron gebruik en hoe die kennis van hierdie gebruik oorgedra en gedeel word, is inligting oor hoe om ʼn beter betrekking en integrering van die gemeenskap in die bestuursprosesse gegenereer. Die studie het die belangrikste plante geïdentifiseer wat tans gebruik word binne die ≠Khomani gemeenskap met die doel om die gebruik van hierdie plante te assesseer. Sosiale netwerkanalise (SNA) is addisioneel gebruik om ondersoek in te stel oor hoe sosiale netwerk struktuur die verspreiding van kennis uitbeeld wat die gemeenskap se vermoë om hulle natuurlike plant hulpbronne effektief te bestuur affekteer. In ʼn etnobotaniese opname, was oor 90 individuele ondervra op die plase wat aan die gemeenskap toegeken was, met die gebruik van semi-gestruktureerde onderhoude. Dit is gevind dat in totaal 59 plant spesies uit 28 families gebruik word. Medisinale plante was meer dikwels aangehaal (60%) met eetbare plante bestaande uit 20%. Data was ook versamel oor sosiale verwantskappe omringende die verkryging, generering en oordra van kennis in die gebruik van plante. Hierdie netwerk van kennis word alles uitgebeeld in geïsoleerde individue op die periferie en ʼn paar individue wat losweg verbonde is tot sentrale strukture. Hierdie studie identifiseer dat die gebruik van wildeplante ʼn belangrike praktyk bly vir die ≠Khomani mense, hoofsaaklik vir medisinale doeleindes. Dit dien as basis inligting van plant hulpbronne wat tans gebruik word deur die gemeenskap en wat by ons begrip gevoeg word oor hoe tradisionele kennis oorgedra word. Die insig wat deur SNA voorsien word beeld die huidige verspreiding van kennis uit, wat deur die gemeenskap gebruik moet word, as ondersteuning van “network weavers” en SANParks om hulle gesamentlike bestuur doelwitte te bereik. “Network weavers” kan potensieel ekologiese onvolhoubare praktyke teenwerk, wat die samewerking en die oordra van tradisionele ekologiese kennis bevorder.