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Spatial distribution, carbon stocks and diversity of tropical African peatlands

Prof Simon Lewis (SoG), Dr Tim Baker (SoG)

Project partner(s): Wildlife Conservation Society (CASE); University of St Andrews; University of Edinburgh

Contact email:

Project Outline

Peatlands are carbon-rich ecosystems that cover just 3% of Earth’s land surface, but store one-third of soil carbon. Peat soils are formed by the build-up of partially decomposed organic matter (OM) under waterlogged anoxic conditions. Most peat is found in cool climatic regions where unimpeded decomposition is slower, but deposits are also found under some tropical swamp forests (Page et al. 2011). School of Geography PhD researchers have recently discovered two very large peat deposits in Western Amazonia (Draper et al. 2015) and the central Congo Basin (Dargie et al. in review). This is having important impacts in terms of our understanding of the conditions under which peat forms, the regionally, and in aggregate globally, significant carbon stocks of tropical peatlands, and applied aspects, such as increasing the legal protection of these newly discovered carbon-rich ecosystems. This PhD project will build on these recent successes, but re-position the research in a new direction.

There are many other swamp forests in tropical Africa, and no details of whether peat exists there. This project will use theories of how peat forms and remotely sensed data from satellites to identify likely areas of peat development. The student will then visit some of these locations to take on the ground measurements (most likely Republic of Congo, Cameroon and/or Gabon), including the vegetation (as most satellite sensors see aspects of this) and bring peat back to the laboratory for analysis. This analysis of peat properties (bulk density, carbon concentration, age from radiocarbon dating) can also assist in understanding how the peatlands in the different areas formed, to begin to assess the diversity of peatlands in lowland tropical Africa. The final part of the research will be to make the first data-driven estimates of the carbon stocks in peat for lowland tropical Africa, rather than just the single Congo Basin swamp we had recently quantified.  Practical outcomes will include adding new information to local management plans (particularly in the context of the new Paris Climate Agreement and REDD+, which may encourage new legal protection of high-carbon-stock ecosystems). The successful student will therefore gain experience in remote sensing, fieldwork, laboratory analyse and some policy-related activity at the end of the programme.

Key aims of the project:

  1. Use, refine and improve newly developed techniques to utilise multiple satellite datasets (radar and optical) to make predictions of where peat will likely occur.

  2. Test these predictions by selecting a small number of locations where we expect large peat deposits, and visit these areas, in conjunction with local institutions (which are already part of the African Tropical Rainforest Observation Network, founded by Professor Lewis, see Lewis et al. 2013, and

  3. Undertake fieldwork, (i) coring samples, (ii) taking in situ peat and hydrological measurements, including electrical conductivity, pH, (iii) measurements of vegetation and aboveground live carbon stocks, (iv) topography measurements – to assess if specific peatlands are domed.

  4. Retrieve peat to analyse in the Leeds laboratory (bulk density, carbon content, radiocarbon dating).

  5. Use fieldwork data to train a model to assess the likely extent of the visited peatlands, using for example, using a maximum likelihood classification.

  6. Scale these results to the continent, via one or more methods (e.g. see Draper et al 2015 for an example).  

  7. Publish the results, and explain them in policy-relevant language to stakeholders in the relevant regions and internationally.

This PhD programme is flexible: the student will co-direct the balance of the research questions asked, given the skills and desires of the student. There may be a greater or lesser focus on fieldwork vs remote sensing analysis vs laboratory work, but the project will include all three elements.

Professor Lewis will lead training of the student, including visiting one of the field sites in Africa with the student, with supervision sessions every two weeks. Supporting supervision and training will be from Dr Tim Baker (University of Leeds), a tropical ecologist, who has mapped peatlands in Amazonia; tropical peat expert Dr Ian Lawson (University of St Andrews); remote sensing expert Dr Ed Mitchard (University of Edinburgh). Laboratory training will be by senior technician Martin Gilpin in the School of Geography. The training will therefore cover field methods, lab methods, remote sensing, and statistical techniques as required.

The successful candidate will need a good first degree in Ecology, Geography or other numerate scientific discipline, and will be enthusiastic to undertake fieldwork in remote and challenging conditions in tropical Africa. Ideally, the candidate will have some experience of using remote sensing data, GIS, tropical fieldwork, robust statistical knowledge, and some experience of following research through to the publication stage. Candidate will likely only have some of these skills prior to the PhD, with the rest acquired thought the training and suverision program.  

The successful candidate will join a thriving group of ecologists and global change researchers and students (, and if they publish their work, will have excellent career prospects, as the majority of our recent PhD students have progressed to full-time research positions or university lectureships following the completion of their PhD.

If you have questions feel free to contact Professor Lewis.

CASE Partner

The CASE Partner in the project is Wildlife Conservation Society - Europe.  Globally, WCS supports the management of ~800,000 km2 of protected areas and operates in 60 countries, including WCS programs in all major Central African countries which the project will draw upon. The primary focus of WCS-Europe, with headquarters in London, is on conservation in Africa. The research will be shaped in conjunction with WCS, including prospecting for peat in areas that WCS co-manage. The research results will support and improve the management plans of these landscapes. The vegetation mapping will improve our understanding of the distribution of biodiversity and resources important to local communities. The peatland mapping will enable assessments of future carbon emissions scenarios and their relevance to the development of site-based and national REDD+ (Reduced Emissions from Deforestation and forest Degradation) strategies. The successful student will spend some time at the London office of WCS learning how scientific results become practical conversation.

References and further reading

Avitabile, V.H., Herold, M., Heuvelink, G.B.M., Lewis, S.L. et al. An integrated pan-tropical biomass map using multiple reference datasets. Global Change Biology,  22, 1406–1420.

Dargie, G. (in review). Carbons stocks of the peatlands of the central Congo Basin.

Draper, F. C. et al. (2014). The distribution and amount of carbon in the largest peatland complex in Amazonia. Environmental Research Letters 9, doi:12401710.1088/1748-9326/9/12/124017.

Lawson, I.T., et al. 2015, 'Improving estimates of tropical peatland area, carbon storage, and greenhouse gas fluxes' Wetlands Ecology and Management, 23, 327-346.

Lewis, S.L. et al (2013). Aboveground biomass and structure of 260 African tropical forests, Philosophical Transactions of the Royal Society B, 368: 20120295.

Lewis, S. L., Edwards, D., Galbraith, D. 2015 Increasing human dominance of tropical forests. Science, 349: 827-832.

Page, S. E., Rieley, J. O. & Banks, C. J. Global and regional importance of the tropical peatland carbon pool. Global Change Biology 17, 798-818, doi:10.1111/j.1365-2486.2010.02279.x (2011).

Related undergraduate subjects:

  • Ecology
  • Geography