Research Interests

Palaeovegetation of southern Africa

I am working with an amazing international team of scientists from the SACP4 project, led by Curtis Marean (Arizona State University), who are investigating human origins along the south coast of South Africa. In order to contextualise the archaeological sites in the landscape during different environmental conditions of the past, we will be using a range of vegetation modelling techniques to tackle how the vegetation may have shifted or changed. Together with Janet Franklin (Arizona State University), we will be using species and community distribution models to predict past distributions. However, species distribution models are handicapped by an inability to include important aspects of plant physiology, the most problematic being that they are unable to include the response to changing atmospheric CO2 concentrations. To deal with this, we are collaborating with Steve Higgins (University of Otago) and Simon Scheiter (Senckenberg Gesellschaft für Naturforschung) who have developed a dynamic global vegetation model that includes fundamental components of physiology (such as response to atmospheric CO2) and other aspects such as fire. We will compare the functional groups predicted by this model with the predictions of species and community distributions models when projected onto past climates to understand and explore potential vegetation changes at a regional scale across southern Africa. A more extensive project outline is available here

General œcology and molecular œcology of the Albany Subtropical Thicket

The Albany Subtropical Thicket was the focus of my PhD dissertation, where I investigated the phylogeographic patterns of three thicket plant species . In collaboration with Richard Cowling and others, I am working on many different aspects of thicket œcology, such as community distribution modelling (e.g. Potts et al. 2013), germination requirements (e.g. Wilman et al. 2014), seed dispersal and testing the importance of capturing evolutionary in conservation planning (e.g. Potts et al. 2014).

Biome boundary drivers

The Eastern Cape of South Africa houses an exceptional diversity of the major vegetation types found in Africa, including fynbos, succulent karoo, Nama-karoo, Albany thicket, grasslands, and savannahs. This area is thus an amazing model system for exploring the abiotic and biotic factors that drive biome boundaries. Together with Robbert Duker (PhD student), we are investigating the effects of minimum temperature (specifically frost) on the distribution of thicket at the thicket-Nama karoo boundary. I have also become interested in flammability across biomes and the evolution of flammability; along with Wynand Calitz (MSc student), we are investigating species-level flammability across the entire range of biomes in the Eastern Cape. I am also exploring the range of potential drivers of biomes in the Humansdorp region in collaboration with Prof. Richard Cowling. This is an amazing return to an old dataset; in order to examine the environmental correlates with vegetation we are re-analysing Richard’s extensive PhD data collected from 1976 to 1980 using modern methods!

A sustainable cup of Honeybush

Honeybush tea is a product that is in exceptionally high international demand. As the industry is still in its relative infancy, we wish to conduct research and provide guidelines promoting Honeybush expansion using ecological, not traditional agricultural, principles. We believe that Honeybush has the potential to be a a great asset for both farmers and conservationists if ecological principles are employed based on the years of accumulated research on Fynbos ecology. Andrea Beyers has conducted experiments to demonstrate that the establishment of a Honeybush crop can go hand-in-hand with rehabilitation efforts of old lands. Nicholas Galuszynski is focusing on the phylogenetic and phylogeographic patterns of Cyclopia and the commercially important species, respectively.  

Phylogenetics networks: intertwining trees and networks

I have a habit of attracting intractable datasets, and this is most prevalent in the field of phylogenetics. The best tools to investigate evolution is usually with a network, especially when the evolutionary story is complex. Yet networks are rarely used, and if they are used then they are often misused or misinterpreted. Guido Grimm (University of Vienna) and I are are developing methods to help researchers intertwine phylogenetic networks and trees. We have had great success in dealing with intra-individual site polymorphisms (2ISPs) (Potts et al. 2014), which are the bane of modern phylogenetic software. If you find yourself at a loss with what to do with your hard-won DNA matrix as none of the current phylogenetic software works, drop us a line :)