Using mathematics and history to predict the future of semi-arid vegetation
Van Leeuwenhoek Lecture on BioScience.
Jonathan Sherratt has been Professor of Mathematics at Heriot-Watt University since 1998. He was an undergraduate at Cambridge, followed by graduate work at the University of Washington. He graduated in 1991 (Oxford), was a postdoc at Oxford University and lecturer and senior lecturer at Warwick before moving to Heriot-Watt.
His research concerns the application of mathematics to problems in ecology, cell biology and medicine. The objective of this research is to use mathematics to obtain a better understanding of complex behavior in biology. Often this involves developing new mathematics in order to study the mathematical models. Specific topics on which his research is focused include spatiotemporal dynamics of cyclic populations, vegetation patterns in semi-arid environments, and long-range cell-cell interactions in developmental biology and tumour growth.
Vegetation in semi-arid regions has complicated dynamics, with a tendency to self-organise into spatiotemporal patterns. Given the lack of laboratory replicates, and the practical difficulties associated with fieldwork, mathematical modelling plays a key role in understanding these dynamics.
In this lecture, Jonathan Sherratt will discuss the ability of simple mathematical models of semi-arid vegetation to provide important and often surprising insights into spatial patterning.
One important feature of the phenomenon is that the ecological and environmental parameters do not on their own determine the pattern wavelength, which depends also on the process leading to patterning. For example, the degradation of uniform vegetation and the colonization of bareground lead to different patterns.. This "history-dependence" means that prediction of future vegetation levels requires detailed information on previous vegetation density and pattern. Focussing on the specific case of the Sahel region of Africa, Jonathan Sherratt will show how this can be obtained by combining modelling with data on climate history. Using predictions of future rainfall levels from global climate models, he will go on to discuss the prediction of future vegetation levels in the Sahel, up to the end of the 21st century - an issue with major ecological and socioeconomic importance.