Plant response to herbivory. Nutrient cycling in natural ecosystems and commercial forestry plantation. Stable isotope ecology. Impacts of elevated CO 2 on plants. Mycorrhizas in natural ecosystems.
Water use efficiency of forest species.
The role of nitrogen fixing organisms in fynbos functioning. Ecosystem impacts of alien plant invasions. Organic nitrogen uptake as a potential explanation for the characteristic 15 N values found in fynbos plants with different mycorrhizal associations. Phylogenetic and functional growth form diversification in the Cape grass Ehrharta Thunb. The embryology, seed coat and conservation of some Kenyan species of the Orchidaceae.