River fragmentation due to the regulation of flows for water supply, navigation and energy is a major stressor impacting river ecosystems worldwide (Grill et al., 2019). The preponderance of artificial barriers such as weirs and dams in many river systems throughout the UK has initiated sustained attempts to mitigate their impacts on fish migration either through the installation of fish passes, or through partial or complete barrier removal (e.g. Kemp & O’Hanley, 2010; Cisowska & Hutchins, 2016). Despite the acknowledged effects of these restoration techniques on some species of migratory fish plus local river geomorphology and water quality, multiple issues still remain to be understood in detail and integrated into planning of fish pass installations and/or barrier removal. In particular, more information is required about impacts on wider aquatic habitats, populations of non-target species such as ‘non-migratory’ fish (Knaepkens et al., 2005) or invertebrates (MacNeil & Platvoet, 2013), the spread of invasive species, and alterations to dispersal and gene flow which are crucial to long-term population viability (Birnie-Gauvin et al., 2018; Wilkes et al., 2018).
This project will be undertaken predominantly focusing on the River Calder in West Yorkshire, in partnership with the Calder Rivers Trust, alongside literature surveys/meta-analyses to develop wider context. Industry has been hugely influential in shaping the river’s form and function. For example, in the nineteenth century, industrialisation led to widespread modification of the river to improve transport for trade, including expansion of the canal system. Advances in technology also saw ever more powerful milling machinery being driven by the water, controlled and directed by dams, weirs, sluices and gates. Many of these physical modifications still remain and contribute to the relatively poor ecological status classifications of rivers throughout the catchment (Environment Agency), although in recent years a series of fish pass and barrier removal projects have been implemented with the aim of improving fish passage, and more are in planning.
The proposed topic is relatively broad and will be focused to suit the expertise and interests of the successful candidate. Example approaches could be to undertake detailed assessments of: (1) Fish and invertebrate communities, surveyed using eDNA approaches, throughout river systems that suffer fragmentation due to weirs and other forms of barriers; (2) Genetic structure of selected populations of fish species above and below barriers; (3) before-after weir removal effects on metacommunities and selected species of fish and/or invasive invertebrates such as signal crayfish. A combined approach of field surveys, experiments and modelling approaches is likely to be utilised. The successful applicant will have opportunities to undertake fieldwork to collect new primary datasets from river systems throughout West Yorkshire, with a primary focus on the River Calder catchment. This study design will allow for analyses of spatial variability in ecological community patterns and processes, plus a consideration of temporal dynamics across several seasons and/or before-after weir removals/fish pass installation in targeted river sections.
The successful candidate will possess at least a good first degree (2i or above), and possibly a masters or relevant practical/work experience in ecology, biology, fisheries management or geography/environmental sciences. They will benefit from inter-disciplinary research training in aquatic ecology, hydrology and geomorphology as part of the River Basin Processes and Management research cluster in the School of Geography, the Ecology & Evolution group in the School of Biology, the wider water@leeds network and through co-supervision at Coventry University. The nature of the project means that the student would be trained in research methods such as biological sample collection/analysis, river water quality analysis, molecular ecology and applied statistics for analysing biological data, both internally and at external workshops. There will be opportunities for placements with the Calder Rivers Trust. An additional important part of the training will be to attend national and international conferences to present results and gain feedback. The student will be encouraged to submit high quality papers for publication during the project.
Informal enquiries should be directed to Lee Brown [Email Address Removed]. Further details about postgraduate research degrees at the School of Geography, University of Leeds can be found here.