Peatlands are globally-important carbon (C) stores, representing approximately one third of the terrestrial C pool. These C stores are now becoming increasingly vulnerable to rising temperatures, as well as land-use changes. Release of C from peatlands, either as the greenhouse gases CO2 and CH4 or as a result of erosion, constitutes a significant potential feedback to global warming. Despite their importance, there remains a large amount of uncertainty concerning the size of peatland C stores - a result of the small-scale spatial heterogeneity in peat depths and plant communities that exists within peatlands. Quantifying spatial variation in plant and soil microbial communities - the biological sources and sinks of C in peatlands - is necessary in order to reduce uncertainty concerning the spatial variation of peatland ecosystem functions. We characterised ecologically and hydrologically distinctive peatland landforms in a UK blanket peatland, determining associations between plant and soil microbial communities and differences in ecosystem functioning between landforms, as well as the contributions of individual landforms to overall ecosystem functioning. Peatland landforms supported distinctive soil microbial communities. Eroding areas and gullies were hotspots for CH4 fluxes and had higher winter global warming potentials than intact blanket peat. A simulated 10% expansion of eroding areas resulted in a loss of C equivalent to 1000 years of C sequestration by the blanket peatland, emphasising the importance of considering individual landforms when assessing peatland ecosystem functioning at the landscape scale. Our approach represents a novel combination of targeted field survey, robust image classification techniques and geostatistics, which could be transferred to other peatlands. The research papers presented in this thesis contribute to our current understanding of the importance of biological diversity for peat land C dynamics, and will establish a theoretical and methodological framework to improve predictions of peatland ecosystem functioning in response to future change.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:663220 |
| Date | January 2012 |
| Creators | Whitfield, Mike G. |
| Publisher | Lancaster University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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