River ecosystem responses to glacier loss
Supervisors: Dr. Lee Brown (enquiries: email@example.com) and Dr. Duncan Quincey
Annapurna region, Nepal (left), Blaisen, Norway (right)
Climate change poses a considerable threat to the biodiversity of high altitude ecosystems, with Arctic alpine regions across the world already beginning to show clear responses to warming (Milner et al., 2017). Glacier mass-balance studies show consistent decreases over the last century in most regions and it has been suggested that retreat may even be accelerating in many locations. Continued negative glacier mass-balance will lead to glacier- and snow-melt reductions (Barnett et al., 2005), proportionally greater groundwater contributions (Brown et al., 2006) and changes in proglacial riverscape dynamics (Malard et al., 2006). These hydrological changes will dramatically alter alpine river communities (Brown et al., 2007; Brown & Milner, 2012; Jacobsen et al., 2012). However, to date most studies have focused on macroinvertebrates, there have been no detailed assessments of responses at higher levels of organisation (i.e. whole food webs; Clitherow et al., 2013; Fell et al., 2017) and we know little about how important ecosystem processes such as primary production or respiration will change. These are major research gaps because the potential for emergent properties in complex systems means it is difficult to predict ecosystem responses, and therefore to accurately inform conservation and management strategies, by simply extrapolating from lower levels of organization (i.e. population responses; Woodward et al., 2010).
The topic is relatively broad and would be focused to suit the expertise and interests of the successful candidate. Example approaches could be to undertake field surveys of how components of food webs (e.g. specific groups such as microbes/algae/macroinvertebrates), their connections via feeding links, and/or functional processes associated with aquatic ecosystems (e.g. nutrient uptake, primary production) are linked to glacier retreat. The project would identify a continuum of rivers to work on, from those draining highly glacierized basins to those with no glacial influence. By examining rivers fed from different water sources, a major output from this project will be predictions about how river ecosystems can be expected to change in response to future climate change. The student will benefit from access to extensive data that already exists for many locations globally (e.g. Brown et al., 2018, Fell et al., 2018), for example allowing comparative studies using the same methods. Links to ongoing projects at Leeds or via collaborators would allow the student to conduct a field campaign in either Peru (e.g. https://gtr.ukri.org/projects?ref=NE%2FS013296%2F1), Scandinavia (via the Norwegian Institute for Water Research, NIVA) or the Himalayas (http://gotw.nerc.ac.uk/list_full.asp?pcode=NE%2FP016146%2F1).
This research is anticipated to allow detailed assessments of: (1) macroinvertebrate/algal and/or microbial community composition, (2) stream food web structure (see e.g. Clitherow et al., 2013). A combined approach of descriptive and experimental approaches may be utilised. The successful applicant will have opportunities to undertake fieldwork to collect their own primary datasets from glacier-fed rivers. This study design will allow comparisons of glacier-fed rivers from different basins and potentially different mountain ranges, and analyses of seasonal dynamics from more intensively monitored rivers.
The successful candidate will benefit from inter-disciplinary training in hydrology and aquatic ecology as part of the River Basin Processes and Management research cluster in the School of Geography, and as part of the wider water@leeds network (i.e. water@leeds: ecology group) and the Leeds NERC DTP. The nature of the project means that the student would have opportunities to be trained in research methods such as river water quality analysis, algal/macroinvertebrate identification, microbial sample collection/analysis, food web construction, measuring functional processes and applied statistics for analysing biological data, both internally and at external workshops. 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.
Barnett TP, Adam JC, Lettenmaier DP. 2005. Nature 438: 303–309;
Brown et al. 2018. Nature Ecology & Evolution 2: 325-333
Brown LE, Hannah DM, Milner AM, Soulsby C, Hodson A, Brewer MJ. 2006. Water Resources Research 42: W08404
Brown LE, Hannah DM, Milner AM. 2007. Global Change Biology 13: 958-966;
Brown LE. & Milner, AM 2012 Global Change Biology 18: 2195-2204
Clitherow L, Carrivick JL & Brown LE. 2013. PLoS One 8(4): e60899
Fell et al. 2018. Global Change Biology 24: 5828-5840
Fell, Carrivick & Brown. 2017 BioScience 67: 897-911
Jacobsen D, Milner AM, Brown LE, Dangles O. 2012. Nature Climate Change 2: 361-364
Malard et al. 2006. Ecology 87: 704–716
Milner…Brown LE et al. 2017. PNAS 114: 9770-9778
Woodward, G., Perkins, D. & Brown, LE. (2010). Philosophical Transactions of the Royal Society B 365: 2093-2106