Impacts of agricultural intensification on ecosystem functioning and trophic relationships in rivers
PhD Research
Funding:
The full studentship (fees and stipend) is available to UK or EU students who have been resident in the UK for at least three years. Other EU participants may receive a fees only award.
Applicants capable of self-funding (UK, EU and international) are also welcome to apply.
Project details:
Primary Supervisor: Dr I. Vaughan
Secondary Supervisors: Prof Bill Symondson & Prof Steve Ormerod
Questions about maintaining farmland biodiversity and ecosystem functioning in the face of agricultural expansion and intensification are amongst the most pressing in current ecology. In the UK, over 40% of the land area is under intensive arable or pastoral agriculture, with much more used for extensive livestock grazing (Countryside Survey 2007). Rising national and global populations, alongside a greater emphasis on food security, will encourage more intensive production, and it is vital to understand and manage the potential effects on both terrestrial and aquatic ecosystems.
Streams draining agricultural land have received little attention compared to terrestrial environments, yet are heavily impacted by agricultural intensification: elevating nutrients and fine sediments; increasing pollution risks; altering hydrology; and modifying terrestrial-aquatic linkages. Large changes in species composition have been documented, but until recently the associated changes in stream ecosystem functioning have been largely ignored. This is unfortunate given the improved mechanistic understanding it affords, and the vital link to the sustainable provision of ecosystem goods and services.
Using a combination of existing data sets, sampling of stream invertebrate communities, measurements of ecosystem functioning and, for the first time in freshwaters, molecular analysis of invertebrate food webs, this PhD will aim to:
- Characterise high-level changes in stream ecosystems that result from agricultural intensification: community structure and trait representation, whole-stream metabolism, macronutrient (C, N, P) flux and predator food webs
- Reveal how trophic interactions among key taxa change with increasing agricultural intensity, relating to concomitant shifts in stream functioning and prey diversity
The PhD will provide excellent, cross-disciplinary training, with field- and laboratory-based components, numerical and GIS-based analyses. The student will be based in a thriving research department and would work alongside others examining freshwater systems and trophic interactions.