Professor Richard Brazier, Department of Geography, University of Exeter
Dr Gemma Coxon, School of Geographical Sciences, University of Bristol
Dr Alan Puttock, Department of Geography, , University of Exeter
Stewart Clarke, National Trust
The NERC Centre for Doctoral Training in Freshwater Biosciences and Sustainability (GW4 FRESH CDT) provides a world-class doctoral research and training environment, for the next generation of interdisciplinary freshwater scientists equipped to tackle future global water challenges. For an overview of the GW4 FRESH CDT please see website http://www.gw4fresh.co.uk
Freshwater ecosystems in developed nations faces pressure from multiple stressors but in particular due to years of degradation of water quality due to the intensive management of catchments resulting from agriculture and point source pollution from high population densities. These stressors are likely to increase in the future as populations continue to expand, predicted changes due to climate lead to increased hydrological extremes and government resources for management and regulation become even more stretched. Alongside the degradation of our surface waters, beavers have been reintroduced to Great Britain after an absence of ca. 400 years. Beavers are ecosystem engineers and keystone species with the ability to transform landscapes dramatically creating complex wetlands. Beaver engineering activity has been shown, in pilot work by the supervisory team, to influence water chemistry and therefore downstream water quality via both abiotic (construction of dams which trap nutrients) and biotic (uptake of nutrients by vegetation) processes. It is believed that there were two key mechanisms affecting the difference in water quality observed at a beaver sites: (1) flow was slowed resulting in the physical deposition of sediment and associated nutrients (2) the site increased in wetness altering the biogeochemical cycling of nutrients.
Research undertaken elsewhere supports these findings but in very different ecosystems. The return of beaver to Great Britain, coincides with an identified need for a greater understanding of the pressures affecting freshwater ecosystems and new integrated solutions to address these pressures. Beaver created wetlands have the potential to address the stressors of poor water quality and habitat simplification together and in dynamic and potentially sustainable way. Now is the time to quantify the impacts of beaver upon sediment and macronutrient dynamics robustly in our freshwater ecosystems.
The research will characterise the impact of beavers upon water quality across a range of sites where beavers are well established and a range of new locations managed by the National Trust where beaver reintroduction is scheduled, or is already underway. The PhD student will be embedded in a research group already studying various aspects of beaver reintroduction including; hydrology, aquatic ecological status, socio-economic impacts, perceptions of beaver reintroduction and modelling to understand beaver habitat, population dynamics and impacts at the landscape scale.
The research will give the PhD student a unique opportunity to develop a growing body of work examining whether beaver can form a valuable component to multi-benefit, catchment management solutions. Taking a Multiple-Before-After-Control-Impact experimental approach, this research will address the following hypotheses:
1. Beaver pond and dam sequences act as sediment traps, storing significant amounts of sediment and reducing downstream suspended sediment concentrations, loads and yields.
2. Beaver engineering activity delivers a positive impact on both diffuse water pollution from agriculture and point source pollution (for example from septic tanks, water treatment works) resulting in downstream reductions in nitrogen and phosphorus concentrations/loads/yields, driven by increased uptake by aquatic plants.
3. Beaver ponds trap and store significant amounts of carbon, upstream of dam complexes and within pond sediments.
4. Impacts of beaver upon water quality are observed across a range of sites, scales and landuses, allowing mechanistic understanding to be upscaled via a suite of modelling tools, to predict the impacts of beaver on water quality at catchment scales.
The student will benefit from strong links to the National Trust and the Environment Agency and will have the opportunity to work closely with beaver reintroduction and catchment management projects. This will enable the student to see first-hand the work of research end-users and gain an understanding of the way in which their science can be used through implementation and wider stakeholder engagement. The student will be offered the opportunity to significant periods of time working directly with the National Trust and gain valuable experience of practical conservation and water management.
Project specific enquiries should be directed to the lead supervisor, Professor Richard Brazier: [email protected]