Browsing by Author "Chimphango, SBM"

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    Rhizobia diversity and their effect on the distribution of indigenous legumes in the Cape Floristic Region
    (2012) Dlodlo, Oscar; Chimphango, SBM; Muasya, AM
    The Cape Floristic Region (CFR) includes a broad variety of bed rocks and soils are a mosaic of sandstone and shale substrates that give rise to a variety of soil types mainly sandstone, aeolian sands, shale, granite and limestone thereby creating heterogeneity in edaphic conditions. Species composition of plant communities in the CFR is predominantly associated with the parent rock, and the resultant overlying soil. The combination of edaphic and topographical variations, local climate gradients and frequent fires is undoubtedly important in promoting species diversity in the region. The family Fabaceae is the second largest family to Asteraceae in the CFR. It is currently comprised of about 760 species, in 37 genera belonging to 18 tribes. Most of these legumes are in symbiotic association with rhizobia that nodulate and fix nitrogen in the nutrient poor soils...It was, therefore, hypothesized that rhizobia isolates from indigenous legumes of the CFR will cluster phylogenically according to soil types and that the distribution of rhizobia limited that of their compatible host.
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    Soil P availability limits legume persistence and distribution in the fynbos of the Cape Floristic Region
    (2010) Power, Simon C; Chimphango, SBM; Cramer, Michael D; Verboom, George Anthony
    Legumes are unable to persist through post-fire succession in fynbos vegetation of the CFR unlike species in families such as Proteaceae and Restionaceae. The majority of fynbos legumes are seeders which tend to be shorter-lived than co-occurring resprouters. Seeders are likely to have a higher nutrient requirement than resprouters as they tend to invest more biomass- above ground, grow faster and produce more seed. In the oligo-trophic soils occupied by fynbos, symbiotic N2-fixation enables legumes to overcome low N availability but not low P availability. I hypothesized that: legumes are less effective at acquiring P from sparingly soluble sources compared with members of Proteaceae and Restionaceae ; legume seeders occupy soils with a higher nutrient status than resprouters. P-acquisition strategies of legumes and non-legumes were assessed.
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    Systematic studies of the southern African Psoraleoid legumes
    (2010) Dludlu, Meshack; Muasya, AM; Chimphango, SBM
    The Psoraleeae are of worldwide distribution, consisting of 185 species in nine genera. More than 60 % of the species are members of the genera, Otholobium C.H.Stirt and Psoralea L., both of which have a centre of diversity in the Cape Floristic Region of South Africa. This dissertation was aimed at conducting a systematic study of the southern African Psoraleeae.
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    Systematics of Ficinia clade (Cyperaceae)
    (2012) Tshiila, Aluwani Athalia; Muasya, AM; Chimphango, SBM
    Cyperaceae is a cosmopolitan graminoid family comprising about 110 genera and over 5500 species, represented in Southern Africa by 30 genera and over 500 species. The family is an integral part of wetland and grassland vegetations, a number of species have various local uses, and several species are notorious weeds in agriculture. The Ficinia clade includes five genera, namely Isolepis, Ficinia, Scirpoides, Dracoscirpoides and Hellmuthia. The clade has a centre of diversity in the Cape Floristic Region (CFR), where over 70% (113 species) of the species occur, with several taxa dispersed into alpine areas of Africa, and to Australasia, Europe and the Americas. This study aims to infer the phylogenetic relationships and patterns of macroevolution in Ficinia clade; to estimate the divergence dates and investigate the role of ecology the speciation of sister species of the genus Ficinia; and to revise the taxonomy of the species in the Ficinia indica complex (F. indica, F. dunensis, F. elatior, F. aff. indica R and F. aff. indica MF).