Ecohydrological self organisation in temperate hillslopes

Current understanding of hydrological processes has been developed largely in isolation from studies of other aspects of ecosystem functioning, despite the clear inter-dependencies between hydrological and ecological processes. This project aims to start addressing this gap by investigating the degree to which temperate hillslopes behave as complex adaptive systems through the interactions and feedbacks between hydrological processes, soils and vegetation. The four general properties of complex adaptive systems are considered to be spatial heterogeneity, localized flows, a self-organizing structure, and nonlinearity. In particular, the project will examine the issue of self organisation through a mixture of field-based monitoring, laboratory experiments and computer modelling. Two case-study hillslopes will be monitored to examine small- and large- scale patterns in soil moisture and their relationship with surrounding vegetation. The hillslopes have similar climate, soils and topography, but differ in relation to their history of management. It is hypothesised that the hillslope which has been largely undisturbed will show a greater degree of heterogeneity / pattern formation in relation to soil moisture and vegetation, than that which has had management interventions (which have disturbed the soil and vegetation structure). Complementary laboratory studies will take place using the Sheffield hillslope flume facility. The aims of these experiments will be to look at the time evolution of hillslope patterns in the presence and absence of plants. The student will join other PhD students using the flume and will benefit from training in the use of the facility and will perform carefully-designed factorial experiments on the effects of vegetation, slope angle, and rainfall intensity on pattern formation. The field and laboratory work will inform a computer modelling component, where the student will gain experience in using and testing existing prototype models of hillslope pattern formation developed at Sheffield and Leeds. The project will deliver new insights into how and when ecohydrological self organisation occurs in temperate hillslopes and the significance of this with regard to larger scale hydrological behaviour. It will provide an excellent package for student training, incorporating elements of field work, laboratory work and computer modelling, enabling the development of a broad technical skills base. The inter-disciplinary nature of this project will bring the student to an important new research frontier which will be of great value to their future scientific career. All key parts of the project are in place, reducing the time the student has to spend preparing each one. The fieldwork component builds on an existing monitoring programme. The laboratory work also builds on existing experiments and the student will be given help in setting up the laboratory hillslope. The modelling component is more one of using and testing existing models rather than writing models from scratch. Therefore, we are confident that the project is suitable for PhD study and that our expectations of the student are appropriate. The project team has an excellent track record of PhD supervision and project completion, with students going on to successful post-PhD careers. The partnership between Leeds and Sheffield Universities together with the CASE partner - the Macaulay Institute - will provide strength and depth across the inter-disciplinary topics of the project. In particular, the Macaulay Institute is well placed to support the fieldwork element of the project, both geographically and through its access to and involvement in existing long-term study sites. The School of Geography at Leeds and the Department of Geography at Sheffield have well-established links though the White Rose network, and the supervisors at the two institutions have worked together previously.