Upland river ecosystem resilience to landscape-scale drought

Project Overview

Climate change is intensifying the frequency and severity of droughts, posing urgent challenges for freshwater ecosystems. To date, research on drought effects on river ecosystems has predominantly focused on natural/semi-natural unregulated systems, in particular lowland groundwater-fed rivers.  These systems often display widespread changes in algae, invertebrate and fish community structure and functioning as a result of drought events². In contrast, little information is available regarding drought-related impacts on upland rivers, which may respond differently to lowland rivers due to contrasting biological communities that are adapted to flashier runoff regimes³. The mainstems of many upland river systems are also heavily-modified by large impounding reservoirs, with prescribed environmental flows (e-flows) maintaining downstream runoff despite wider landscape-scale drought.  In contrast, unregulated upland headwater tributaries remain susceptible to drying.

This studentship will test the hypothesis that during this drought phase, regulated rivers will be less impacted than tributary streams both in terms of their biodiversity and functional process rates. This is because maintained e-flows deliver water as well as buffer thermal extremes, thus minimising habitat fragmentation and species competition for space/resources. As a consequence, we might expect e-flow systems to act as ‘refugia’ to facilitate faster biotic recovery and  recolonization post-drought.  Alternatively, this might not be the case if these refuge areas host higher densities of large consumers such as fish, which would otherwise also inhabit small tributary streams that are currently lacking flow.

This PhD project builds on a decade of ecological monitoring across >30 upland rivers in northern England. It will investigate how drought affects river biodiversity and ecosystem functioning and assess the role of reservoir outflows (environmental flows or “e-flows”) in buffering these impacts.

The research will address three core questions:
1. How are upland river ecosystems affected by drought, both structurally and functionally?
2. Do reservoir outflows provide refugia for biodiversity during drought?
3. Can e-flows enhance post-drought recovery and resilience across river networks?

Methodology

You will work with a rich dataset spanning algae, invertebrates, fish, and ecosystem processes (e.g., leaf litter decomposition, algal accrual), collected before and recent drought. Fieldwork will be conducted across the Aire, Calder, and Don catchments, including regulated and unregulated rivers.

Key methods include:
– Multidimensional ecological stability analysis to assess resistance and resilience.
– Trait-based biodiversity assessments to understand species strategies under stress.
– Metacommunity modelling to explore dispersal and habitat connectivity.
– Functional process measurements using standard protocols (e.g., mesh bags, chlorophyll-a tiles).

You will also contribute to long-term monitoring and collaborate with stakeholders including the Environment Agency and Yorkshire Water.

Why Apply?

This PhD offers a unique opportunity to:
– Join a leading interdisciplinary team with expertise in hydrology, freshwater ecology, and environmental management.
– Contribute to urgent climate resilience research with real-world policy and management implications.
– Access extensive pre-existing datasets and a well-established river monitoring network.
– Engage with industrial partners and policy-makers to co-create solutions for future drought resilience.

Candidate Profile

We welcome applicants from diverse backgrounds with:
– A strong academic record in ecology, environmental science, hydrology, or related fields.
– Experience or interest in freshwater fieldwork and ecological data analysis.
– Motivation to work across disciplines and with external stakeholders.
– Skills in GIS, R/Python, or ecological modelling (desirable but not essential).

How to Apply

Applications will be accepted through the YES- DTN at the University of Leeds.
For informal enquiries, contact Dr Megan Klaar at [email protected]