My research concerns the biology and ecology of sub-Antarctic islands, and is carried out on Marion and Prince Edward islands. My main interest is the structure and function of the islands' ecosystems, especially in relation to climatic- and human-induced changes. In order to have a framework against which to detect and quantify these changes, much effort put into describing and classifying the islands' terrestrial habitats, based on soil chemistry and vegetation factors. I recently extended the classification to include functional parameters such as primary production and nutrient cycling, I am currently working on a whole-island model of ecosystem functioning. A start has been made to incorporate carbon exchange processes, such as soil respiration and community carbon gains and losses, into the model. The interaction between climate change and invasive alien biota at the islands is a particularly fascinating phenomenon which colleagues and I are researching. Mosses are especially effective indicators of environmental regimes and gradients on the islands and I am involved in a project on the taxonomy and ecology of the islands' mosses.