Project highlights

  • Riparian tree planting is often implemented to help reduce high river temperature extremes, but this could have unintended consequences for instream plant (‘macrophyte’) assemblages. This PhD will develop a ‘toolbox’ that explores these tradeoffs and guides where riparian planting opportunities could be prioritised.  
  • An interdisciplinary supervisory team will support the candidate alongside industrial partners to provide wide ranging expertise in river management and help translate applied research into practice.  
  • The candidate will gain a highly employable skillset spanning various desktop-based (e.g., statistical and geospatial analyses) and practical field-based (e.g., water quality and ecological monitoring) techniques.  
  • The PhD will be delivering novel science to help create more resilient river ecosystems that are becoming increasingly vulnerable to ongoing climate change. 


Climate change threatens to exacerbate high water temperature extremes in rivers by increasing energy (heat) inputs and drought (low flow) severities1, which has significant implications for nature and people (e.g., loss of iconic species)2. Consequently, riparian tree planting is being increasingly advocated to mitigate river temperature peaks1. However, such initiatives may alter instream plant (‘macrophyte’) populations, many of which depend on adequate sunlight3,4. Consequently, riparian planting strategies are required that recognise tradeoffs in potential restoration outcomes, which this project aims to address within the context of a changing climate.   

This research will take place across “chalk” (a fine-powdered limestone) rivers spanning different regions of southern England. This includes the Hampshire Avon and Itchen catchments (both of which being designated ‘Special Areas of Conservation’ due to their unique biodiversity), as well as rivers draining the Chilterns ‘Area Of Outstanding Natural Beauty’. Over 80% of the world’s chalk rivers are located in England and are internationally iconic due to their “gin clear” waters that enhances biodiversity, and specifically macrophyte communities5. Groundwaters feeding chalk rivers typically maintain cool summer temperatures, but thermal ‘spikes’ can occur during warm, low flow periods and exert drastic ecological consequences5 

The successful candidate will draw on the expertise of the interdisciplinary supervisory team, who specialise in river-based processes and translating scientific research to management solutions6,7. River temperature and macrophyte sensitivities to varying shading intensities, hydroclimatic variations and habitat conditions will be quantified using catchment-wide secondary data analyses and detailed fieldwork campaigns. The candidate will use their collected data to predict how different riparian plantings strategies would simultaneously influence both river temperature and macrophyte assemblages under different hydroclimatic scenarios. The candidate will incorporate these model outputs within a ‘toolbox’ that provides guidance to practitioners on where riparian planting practices may be prioritised to mitigate high river temperature extremes, whilst simultaneously avoiding unintended detrimental consequences for macrophyte communities. For instance, planting downstream of cool, groundwater inputs may be advocated, but reaches with diverse macrophyte assemblages may be assigned lower prioritisation scores. The PhD will therefore be delivering cutting edge science that will help safeguard vulnerable river ecosystems within a changing climate. 

An image of a river with some overhanging tree cover and instream plant growth for a PhD studentship advertisement.

Figure 1: A chalk river partially lined by riparian tree cover that supports dense macrophyte assemblages 

CENTA Flagship

This is a CENTA Flagship Project


University of Birmingham


  • Climate and Environmental Sustainability
  • Organisms and Ecosystems


Project investigator

Dr James C. White (University of Birmingham; [email protected])


Prof. David Hannah (University of Birmingham, [email protected])

Dr Judy England (Environment Agency, [email protected])

Dr Ponnambalam Rameshwaran (Centre for Ecology and Hydrology; [email protected])

How to apply


The successful candidate will collate multi-decadal secondary datasets on river temperature (e.g., Surface Water Temperature Archive), macrophyte (e.g., LEAFPACS), shading (e.g., LIDARderived Vegetation Object Models) and hydrological (e.g., National River Flow Archive) data from regulatory monitoring and project partners. Moreover, river temperature timeseries will be made available via a national-scale temperature model designed by the supervisory team. A detailed river temperature macrophyte and monitoring network will be established in the field and collected alongside a suite of environmental measurements (e.g., solar radiation and shading levels, groundwater inputs, flow velocities). Statistical models will be constructed using state-of-the-art (including machine learning) techniques to quantify river temperature and macrophyte responses to key controls measured. These relationships will be modelled under different UKCP18 climate change scenarios, which will help prioritise where planting could be most effective. The candidate will translate these models into a toolbox within an online interactive web application.   

Training and skills

Students will be awarded CENTA2 Training Credits (CTCs) for participation in CENTA2-provided and ‘free choice’ external training. One CTC equates to 1⁄2 day session and students must accrue 100 CTCs across the three years of their PhD.  

The supervisory team will equip the candidate with an interdisciplinary knowledgebase and skillset. Training will be provided in skills relating to freshwater ecology (namely macrophyte surveying), field experimentation, database management, statistical and geospatial analyses of secondary datasets. These skills developed will be beneficial for multiple career pathways. This includes academia, whereby the student will be supervised by a multi-institutional team that will support the writing of peer-reviewed journals and attending scientific conferences. The student will also be well equipped for a career in industry through developing a toolbox and working alongside the Environment Agency and industrial project partners.  

Partners and collaboration

The partners will meet quarterly with the student and the supervisory team to provide overarching guidance on study progression and student development. The successful candidate will particularly benefit from project partner inputs on the ecology of macrophyte communities, corresponding surveying techniques and regional knowledge guiding which specific study locations could be sampled.  Environment Agency, Wessex Water plc. and ESA-UK will supply globally unique, long-term macrophyte datasets3,4. The partners will also provide expertise pertaining to river restoration influences on instream environments, and help guide the toolkit development to ensure its uptake by practitioners and use informing real world restoration projects. 

Further details

Further details on how to contact the supervisor for this project and how to apply for this project can be found here: 

For any enquiries related to this project please contact Dr James C. White, [email protected]. 

To apply to this project: 

  • You must include a CENTA studentship application form, downloadable from: CENTA Studentship Application Form 2024. 
  • You must include a CV with the names of at least two referees (preferably three) who can comment on your academic abilities. 
  • Please submit your application and complete the host institution application process via:   Please select the PhD Geography and Environmental Science (CENTA) 2024/25 Apply Now button. The CENTA application form 2024 and CV can be uploaded to the Application Information section of the online form.  Please quote 2024-B47  when completing the application form. 

Applications must be submitted by 23:59 GMT on Wednesday 10th January 2024. 

Possible timeline

Year 1

  • Complete literature reviews on: (i) river temperature responses to hydroclimatic and habitat controls; (ii) macrophytes responses to biotic and abiotic drivers; (iii) statistical and geospatial techniques that can model river temperature and macrophyte responses to various controls.  
  • Identification of field work locations.  
  • Undertake various CENTA and external training sessions. 
  • Training in macrophyte identification and statistical / geospatial analyses. 

Year 2

  • Collate and process secondary datasets.  
  • Undertake primary data (fieldwork) collection.  
  • Undertake CENTA and external training sessions. 
  • Attend national and/or international scientific conference.  

Year 3

  • Undertake primary data (fieldwork) collection.  
  • Analyse remaining primary data and secondary data sets.  
  • Attend national and/or international scientific conference.  

Year 4 (half year):  

  • Write up findings for thesis submission.  

Further reading

  1. White, J. C., Khamis K., Dugdale S., Jackson, F. L.,  Malcolm, I. A., Krause, S. and Hannah, D. M. (Accepted) Drought impacts on river water temperature: a process-based understanding from temperate climates. Hydrological Processes 
  2. Ficklin, D.L., Hannah, D.M., Wanders, N., Dugdale, S.J., England, J., Klaus, J., Kelleher, C., Khamis, K. and Charlton, M.B. (2023) Rethinking river water temperature in a changing, human-dominated world. Nature Water, 1(2), pp.125-128. 
  3. White, J. C., House, A., Perkins, M., Fornaroli, R., Wood, P. J., Wilby, R. L., Hannah, D. M. and Hill, M. J. (Under Review) River flow regimes and habitat conditions interactively control a keystone macrophyte (Ranunculus penicillatus subsp. pseudofluitans). Journal of Applied Ecology 
  4. Westwood, C.G., Teeuw, R.M., Wade, P.M., Holmes, N.T.H. and Guyard, P. (2006) Influences of environmental conditions on macrophyte communities in drought‐affected headwater streams. River Research and Applications, 22(6), pp.703-726. 
  5. Hampshire and Isle of Wight Wildlife Trust (2022) In Hot Water: How Temperature Affects Chalk Streams. Available at: (Accessed 16/9/2023). 
  6. Jackson, F.L., Hannah, D.M., Ouellet, V. and Malcolm, I.A. (2021) A deterministic river temperature model to prioritize management of riparian woodlands to reduce summer maximum river temperatures. Hydrological Processes, 35(8), p.e14314. 
  7. England, J., Naura, M., Mant, J. and Skinner, K. (2020) Seeking river restoration appraisal best practice: Supporting wider national and international environmental goals. Water and Environment Journal, 34, pp.1003-1011.