Peatland Diversity and Carbon Dynamics

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The winning talk at the Macaulay Land Use Research Institute's annual Student Seminar Day, given by Mike Whitfield as part of his PhD research.

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  • Driven by hydrology
  • Measuring ecosystem function: GHG fluxes
  • Significant differences in methane flux between all landforms (ANOVA, p < 0.001)
  • Peatland Diversity and Carbon Dynamics

    1. 1. PeatlandDiversity and Carbon Dynamics<br />Mike Whitfield<br />Nick Ostle, Richard Bardgett, Rebekka Artz<br />miit@ceh.ac.uk | www.mikewhitfield.co.uk<br />
    2. 2. Background:<br />Peatlands and climate change<br /> Above- and below-ground links<br />Research:<br />Plant and soil diversity<br />Peatland carbon stocks<br />Greenhouse gas emissions (CO2, CH4, N2O)<br />Conclusions<br />
    3. 3. Introduction: Peatlands<br />Globally, peatlands constitute 25 – 30% of the soil carbon pool<br />Climate warming is projected to be greatest over high northern latitudes, coincidental with a high proportion of the world’s peatlands<br />Roughly 8% of UK is covered with blanket peat moorland<br />Map data: Jones et al. 2005: Estimating organic carbon in the soils of Europe for policy support. DOI: 10.1111/j.1365-2389.2005.00728.x<br />
    4. 4. Introduction: Peatlands<br />Globally, peatlands constitute 25 – 30% of the soil carbon pool<br />Climate warming is projected to be greatest over high northern latitudes, coincidental with a high proportion of the world’s peatlands<br />Roughly 8% of UK is covered with blanket peat moorland<br />
    5. 5. To a depth of 1m, UK peatlands contain 1357Mt C, nearly half of which is in Scotland<br />A loss of 12% of the UK peatland area <br />= total annual UK human GHG emissions<br />(Bradley et al. 2005; Smith et al. 2010)<br />
    6. 6. Introduction: Climate-Carbon Feedback Uncertainty<br />Estimates of global soil organic carbon stocks range between 700 – 2946 x 1012kg<br />Need reliable estimates based on upscaling processes from small to larger scales to resolve uncertainty.<br />‘Bucket and slab’ peatland models<br />What about the biological functioning?<br />
    7. 7. Introduction: Linking Plant and Soil Biodiversity<br />Growing evidence of feedbacks between the biosphere and global biogeochemical cycles.<br />Plant-soil interactions lie at the heart of these feedbacks.<br />Climate change and land use are powerful drivers of change in plant diversity. <br />What will the implications be?<br />Pendall et al. 2008<br />
    8. 8. Main Questions<br />Are there any relationships between plant diversity-abundance and microbial community structure at the landscape scale?<br />Can these relationships be used to predict ecosystem scale greenhouse gas emissions?<br />How little do I need to know about biodiversity to predict ecosystem C cycling and GHG emissions?<br />
    9. 9. Field Site: Trout Beck, Moor House, north Pennines<br />Area: 1146 ha<br />Altitudinal range: 535 – 848m<br />90% blanket peat<br />
    10. 10. Upscaling Peatland Carbon Dynamics<br />Survey of peatland condition (plant-soil diversity and carbon stocks)<br />Measurement of peatland GHG function<br />Statistical analyses and spatial modelling of both (LiDAR, image classification and geostatistics (e.g. regression kriging)<br />…to predict carbon dynamics and greenhouse gas fluxes at the ecosystem scale<br />
    11. 11. Peat Bog Landforms<br />
    12. 12. Peat Bog Landforms<br />
    13. 13. Methodology: soil-sampling<br /><ul><li>Large-scale vegetation survey (419 quadrats)
    14. 14. Species presence and percentage cover
    15. 15. Vegetation height at 3 in-plot locations
    16. 16. Habitat context
    17. 17. Topography: aspect, slope
    18. 18. Peat depth</li></ul>Soil C and N<br />PLFA<br />T-RFLP<br />
    19. 19. Methodology: soil-sampling<br />Spatial distribution of soil sampling<br />Coring locations randomly selected based on membership of landform (OM, EA, GU) and depth (0-100, 100-200, 200-300cm) categories<br />Microbial community sampling:<br />Three depths within each core<br />Based on mean water table conditions derived from published and unpublished data<br />0-5cm: Acrotelm<br />15-20cm: Mesotelm<br />75-80cm: Catotelm<br />
    20. 20. Landscape Survey Results<br />Open moorland: 52%<br />Eroded areas: 11%<br />Gullies: 12%<br />
    21. 21. Landscape Survey Results<br />Open moorland: 52%<br />Eroded areas: 11%<br />Gullies: 12%<br />
    22. 22. Above-ground: Vegetation Composition<br />
    23. 23. Below-ground: Peat Depths<br />Deepest peat under open moorland<br />Kruskal-Wallis test indicates significant differences between landform types (p < 0.001)<br />
    24. 24. Below-ground: Carbon Stocks<br />Significantly lower CN ratio in gullies(ANOVA, f =34.6, p <0.001)<br />Higher C content in gullies<br />(Kruskal-Wallis, p <0.001)<br />
    25. 25. Below-ground: Microbial community<br />Significant differences between landforms for Actinobacterial and Total PLFA (Kruskal-Wallis tests: p <0.001 and p = 0.005 respectively)<br />Perhaps reflecting lack of plant inputs on bare peat in eroding areas…<br />
    26. 26. Below-ground: Microbial community<br />Significant difference in vegetation cover between landforms (ANOVA, p <0.001)<br />a<br />a<br />b<br />
    27. 27. Greenhouse Gas Fluxes: Experimental Design<br />What are the differences in greenhouse gas fluxes between landforms?<br />36 chambers on fixed plots<br />3 landforms<br />3 depth classes<br />4 replicates<br />CO2<br />CH4<br />N2O<br />
    28. 28. Greenhouse Gas Fluxes: Experimental Design<br />Monthly sampling using static dome chambers, Infra-Red Gas Analysers (IRGAs) and gas chromatography<br />Continuous landform hydrology and temperature measured using automated dip wells<br />Seasonal sampling for C and N, microbial PLFA and T-RFLP<br />May 2010 to June 2011<br />Image: Sue Ward<br />
    29. 29. Greenhouse Gas Fluxes: Preliminary Results<br />
    30. 30. Upscaling Peatland Carbon Dynamics to the Ecosystem Scale<br />
    31. 31. Conclusions so far…<br /><ul><li>Are there any relationships between plant diversity-abundance and microbial community structure at the landscape scale?
    32. 32. Differences in the composition of Plant Functional Types between landforms are clearly visible
    33. 33. Eroding areas have lower microbial biomass, which may be a reflection of lower vegetation cover on bare peat
    34. 34. Are there differences in below-ground carbon dynamics between landform types?
    35. 35. Gullies have a greater carbon content, and a lower CN ratio
    36. 36. Can these relationships be used to predict ecosystem scale greenhouse gas emissions?
    37. 37. How little do I need to know about biodiversity to predict ecosystem C cycling and GHG emissions?</li></li></ul><li>Acknowledgements<br />This talk can be downloaded from www.mikewhitfield.co.uk<br />Many thanks to:<br />Catherine Turner, Sean Case, Simon Oakley, Susan Ward, Sergio Menendez Villanueva, Harriett Rea, Paula Reimer, David Beilman and Nicola Thompson<br />Mike Whitfield is supported by a Natural Environment Research Council CASE studentship.<br />

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