Peatland Diversity and Carbon Dynamics - BES 2011

PeatlandDiversity and Carbon Dynamics
Mike Whitfield
Nick Ostle, Richard Bardgett, Rebekka Artz
miit@ceh.ac.uk | www.mikewhitfield.co.uk

Background:
Peatlands and climate change
Above- below-ground links
Research:
Landform, plant and soil diversity
Peatland C and N
Greenhouse gas emissions
Conclusions

Peatlands and climate change
Introduction: Peatlands and Climate Change
To a depth of 1m, UK peatlands contain 1357Mt C, nearly half of which is in Scotland
A loss of 12% of the UK peatland area
= total annual UK human GHG emissions
(Bradley et al. 2005; Smith et al. 2010)

Introduction: Linking Plant and Soil Biodiversity
Plant-soil interactions lie at the heart of feedbacks between the biosphere and global biogeochemical cycles.
Climate change and land use are powerful drivers of change in plant diversity.
Can we use understanding of plant-soil interactions in peatlands to predict biogeochemical functioning?
Pendall et al. (2008) Functional Ecology 22 (6)

Main Questions
Are there any relationships between plant and microbial community structure at the ecosystem scale?
Can these relationships be used to predict ecosystem scale carbon storage and greenhouse gas emissions?
How little do we need to know about biodiversity to predict ecosystem C cycling and GHG emissions?
Image: R. Bardgett

Field Site: Trout Beck, Moor House, north Pennines
Area: 1146 ha
Altitudinal range: 535 – 848m
90% blanket peat

Peat Bog Landforms
Open moorland
Gully
Eroding area

Above-ground: Vegetation Composition
Open moorland
Gully
Eroding area

Methodology: Peatland survey
Large-scale vegetation survey
Composition and height
Topography
Peat depth
Soil C and N
Microbial community composition
By PLFA and M-TRFLP
0-5cm: Acrotelm
15-20cm: Mesotelm
75-80cm: Catotelm

Below-ground: Peat Carbon and Nitrogen
Gullies are less nutrient-limited and a focus for biogeochemical cycling…

Below-ground: Microbial community PLFAs
Lower total PLFAs in eroding areas reflects lack of plant inputs
Declining trend in total PLFAs with depth
Suggestion of a lower fungal-bacterial ratio in gullies
(f = 70, p < 0.01)
(f = 12, p < 0.01)
n.s.
(f = 24.7, p < 0.01)

Greenhouse Gas Fluxes: Experimental Design
Monthly sampling using static dome chambers, Infra-Red Gas Analysers (IRGAs) and gas chromatography
Continuous landform hydrology and temperature
June 2010 to May 2011
Image: Sue Ward

Water table measurements

Greenhouse Gas Fluxes: CO2 from June 2010 to May 2011
Summer
Winter

Greenhouse Gas Fluxes: CH4 from June 2010 to May 2011
Summer
Winter

Conclusions so far…
Are there any relationships between plant diversity-abundance and microbial community structure at the landscape scale?
Differences in the composition of Plant Functional Types between landforms are clearly visible
Eroding areas have lower total PLFAs, which may be a reflection of lower vegetation cover on bare peat
Are there differences in below-ground carbon dynamics between landform types?
Gullies have a greater carbon and nitrogen concentration, and a lower CN ratio
Can these relationships be used to predict ecosystem scale greenhouse gas emissions?
Gullies emit larger quantities of methane and carbon dioxide than other landforms

Acknowledgements
This talk can be downloaded from www.mikewhitfield.co.uk
Many thanks to:
Catherine Turner, Sean Case, Simon Oakley, Susan Ward, Sergio Menendez Villanueva, Harriett Rea, Paula Reimer, David Beilman and Nicola Thompson
Mike Whitfield is supported by a Natural Environment Research Council CASE studentship.

Peatland Diversity and Carbon Dynamics - BES 2011

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