Future droughts are predicted to be characterised by hotter temperatures, longer durations and greater spatial extent. Freshwater ecosystems, and particularly upland stream ecosystems, are at risk since climate-derived droughts are likely to combine with increasing human demands for water supply. Droughts will also interact with pollution, e.g. from agriculture. The consequences for stream ecological communities and processes (e.g. decomposition, production) depends on the intensity of exposure to drought, namely the ecologically available water remaining, as well as the sensitivity (e.g. species traits or physiology, community structure), adaptive capacity (e.g. phenotypic plasticity, dispersal) and resilience (an emergent property) of the stream biota. Larger disturbances that overwhelm the capacity of the stream ecosystem to cope are likely to lead to significant ecological changes. Our research has been core to the growing evidence of the impact of climatic changes on streams through temperature increase, alterations in organic matter processing, but there is limited understanding of the potential impacts of severe ecological drought on upland stream ecosystems. Natural Resources Wales (NRW) estimates that average natural summer flows in rivers could reduce by between 50-80 % in future. The severity of droughts is thus likely to escalate from temporary small-scale responses (e.g. reduced productivity) to more widespread and persistent transformations (e.g. species extinction) with knock-on effects on key ecosystem-services such as salmonid populations on which substantial Welsh tourism relies. While there is increasing recognition that the provision of ecosystem-services relies on functioning ecosystems, severe drought could lead to poor trade-off decisions between competing ecosystem and human needs unless there is appropriate planning and managed adaptation. This PhD will help identify strategies to cope with climatic change that are viable in the long-term both for nature and the well-being of people. Our aim is to understand how ecological droughts affect the structure/functioning of upland stream ecosystems.
The research will:
1. Identify the sensitivity and adaptive capacity of organisms and key functional guilds (thermal and dispersal traits, physiology, functional structure, plasticity)
2. Determine the sensitivity of key ecological processes (e.g. litter decomposition, invertebrate biomass production,foodweb efficiency)
3. Model the relationship between climate patterns and indicators of stream vulnerability using our long-term data to determine ecological drought thresholds and forecast long term risks
4. Consider human interventions to reduce the vulnerability of stream ecosystems, in terms of exposure (e.g.modification of hydrological processes that influence the time, spread and level of ecological drought at stream scale) or sensitivity and adaptive capacity (e.g. through natural resource management actions)
The student will lead the specific design of the project, which is supported by extensive, historical data held by the partners on hydrological, climatic and ecological data, spanning 40 years, collected across the Welsh uplands and at the Llyn Brianne Stream Observatory. The student will combine modelling analysis with experimental work using the Observatory stream mesocosms. As well as being part of the FRESH community, the host institutions have large early-career communities with which the student will interact. Additionally, the stakeholder partner offers opportunities for short internships to develop real-world problem solving skills.
Studentships will last for 3.5 years full-time or the equivalent period part-time.
The application deadline is 9am on 16th December 2019.
HOW TO APPLY
Applicants must apply directly to the CDT and not via Cardiff University’s online application system. Please use the below link which will take you to the relevant page to place an application to the CDT directly: https://cardiff.onlinesurveys.ac.uk/gw4-fresh-cdt-student-application-202021
For more details on how to apply, please visit the GW4 Fresh website: https://www.gw4fresh.co.uk/how-to-apply/doctoral-students/