Members

 Rob Duker

Rob Duker (PhD) (Co-PI on DEA-funded Spekboom restoration research)

Rob's current research focuses on the effects of winter frost events on two Southern African biomes, the Nama-Karoo shrubland and Subtropical Thicket. Thicket is found along the comparatively warm sub-escarpment lowlands, and is a low-growing evergreen forest-type vegetation. The Nama-Karoo shrubland is found on the frosty high-altitude interior plateau, and is comprised of dwarf shrubs with tiny leaves, a characteristic of aridity and cold-tolerant vegetation. We have shown that naturally growing thicket species are extremely intolerant of laboratory freezing, and seedlings of thicket species cannot survive in frost-exposed areas currently dominated by Nama-Karoo shrubland. Rob's research has shown that the distribution of thicket is limited by the occurrence of sub-zero temperatures and frost, likely a relic of its Eocene rainforest origins. This has immediate regional-scale planning implications for the restoration of livestock-degraded thicket, which is done by planting Portulacaria afra (a highly frost-intolerant species) in areas of the Eastern Cape of South Africa. 

Primary supervisor: Dr Alastair Potts
Co-supervisors: Prof. Richard Cowling and Dr Derek du Preez

Publications:
Duker, R., Cowling, R.M., du Preez, D.R., van der Vyver, M.L., Weatherall-Thomas, C.R., Potts, A.J., 2015. Community-level assessment of freezing tolerance: frost dictates the biome boundary between Albany subtropical thicket and Nama-Karoo in South Africa. Journal of Biogeography 42, 167–178.

Duker, R., Cowling, R.M., du Preez, D.R., Potts, A.J., 2015. Frost, Portulacaria afra Jacq., and the boundary between the Albany Subtropical Thicket and Nama-Karoo biomes. South African Journal of Botany. doi:10.1016/j.sajb.2015.05.004.


 
Susan Botha

 Susan Botha (PhD candidate)

Susan aims to determine the potential carbohydrate return rates of edible plant foods for the southern Cape, how it differs between vegetation types and season, and how it compares with other hunter-gatherer society diets. She also aims to determine how resilient different plant species are to foraging and whether plant food yield varies between burnt and unburnt fynbos. As part of her research, she will also looking at the comparison between archaeological and contemporary use of indigenous plants and the plant preservation methods used by early humans.  

Primary supervisor: Dr Alastair Potts
Co-supervisors: Prof. Richard Cowling and Prof. Karen Esler
   


Nicholas Galuszynski (PhD Candidate) 

Nicholas’ current research aims to map the historic and contemporary gene flow patterns within the commercially important genus Cyclopia, more commonly known as honeybush. Recent expansion of the honeybush industry has resulted in extensive movement of genetic material and the increase in a number of species’ geographic ranges, potentially resulting in the release of new genetic material into wild populations as well as the formation of novel hybrid species. On the other hand, the high demand for wild tea has resulted in the illegal and unsustainable harvesting of wild populations resulting in many commercially important species becoming recognised as declining and near threatened, likely resulting in extensive genetic bottlenecks within exploited populations. These genetic issues have important consequences for the management and conservation of the genus as well as the long term sustainability of the honeybush industry in South Africa. Using molecular techniques in conjunction with ecological studies, Nicholas aims to develop a well resolved understanding of the effects and state of gene flow within Cyclopia. 

Primary supervisor: Dr Alastair Potts
Co-supervisors: Prof. Richard Cowling
 

Timothy Macqueen (MSc Candidate) 

Timothy's research aims to produce a toolkit that will screen for hybridization between Protea species in the Cape Floristic Region.  Currently there are very few examples in the scientific literature of hybridisation of Fynbos plant species in the Eastern and Western Cape provinces. Nevertheless, absence of evidence is not a suggestion that hybridization is absent in these regions. Leading researchers suggest that hybrids do occur naturally across a wide variety of lineages and that human-mediated transport of species may cause issues of hybridization (“frankenflora”). But these suggestions have not yet been investigated. Timothy aims to determine if morphology is sufficient to identify differences between hybrid individuals of different Protea species. To do this he is busy corroborating morphology with genetic data or demonstrating that it is insufficient to detect using differences between hybrids and non-hybrid plants. The next step is to develop a way to genetically screen a large population quickly and cheaply for hybrid individuals using HRM (High Resolution Melt Analysis). 

Primary supervisor: Dr Alastair Potts

Past students
PhD
  • Dimitri Veldkornet (2016) Thesis title: Estuarine species and habitats: distribution and connectivity.
    • Primary supervisor: Prof. Janine Adams; co-supervisor: Dr Alastair Potts
MSc
  • Wynand Calitz (2018) Elucidating the heterogeneity of flammability in the Eastern Cape of South Africa.
    • Primary supervisor: Dr Alastair Potts; co-supervisor: Prof. Richard Cowling
  • Andrea Beyers (2016) Thesis title: Ecological principles for Honeybush (Cyclopia spp.) conservation and cultivation.
    • Primary supervisor: Dr Alastair Potts; co-supervisor: Prof. Richard Cowling
  • Debbie du Preez (2017) Thesis title: Phylogeny and phylogeography of dominant surf zone diatoms.
    • Primary supervisor: Prof. Eileen Campbell; co-supervisors: Dr Derek du Preez and Dr Alastair Potts
Honours
  • Nicholas Galuszynski (2015). Project title: A short history of biome boundaries in a biodiversity hotspot.
  • Lauren Bailey (2016). Project title: Do Fynbos plants with “wand” traits differ in flexibility? Implications for climbing rodent herbivores.
  • Megan Smith (2016) Biome transitions: Investigating a shifting life history strategy in Cyclopia spp (Vent.).