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  • Understanding Anthropogenic Impact on Peatlands

    GHGs

    Dominique Blain, PhDDominique Blain, PhD

    IPCC TFI Side EventM iti H t l BMaritim Hotel, Bonn

    8 June 2011

    Drawing from Quinty and Rochefort, 2003

  • Page 2

    A P d A hA Proposed Approach

    Measuring GHG fluxes

    Understanding drivers of GHG dynamics Understanding drivers of GHG dynamics

    Understanding GHG dynamics in degraded, rewetted and restored peatlandsrewetted and restored peatlands

    Putting it all together

  • Peatlands are the main wetlands reservoir for soil C. World-wide they contain about 450 Gt C, most in the northern peatlands & about 60 Gt in tropical regions (this number very uncertain).

    After Strack et al. 2008. Peatlands and Climate Change. International Peat Society, Vapaudenkatu, Jyvaskyla, Finland.

  • Page 4Measuring GHG fluxes in northern peatlands (g C m-2 yr-2)

    R E t R i ti

    NEE = GPP - Re78 ±59413 ±92

    GPP – Gross primaryproductivity (CO2)

    Plant respiration(CO2)

    Soil respiration(CO2)

    Re - Ecosystem Respiration

    491 ±1308 ±7

    ( 2)

    vascular plants

    ( 2)Methane flux

    (CH4)

    491 ±130

    moss

    water table

    methane oxidation

    Peat/soil

    water table

    methanogenesis

    NEP = - NEE 20 ±12Blain & Lafleur, 2010

  • Page 5Compilation of annual measured C budgets for peatland sitespeatland sites

    C = CO2-C + CH4-C + DOC + Cppt

    in250

    300Worrel et al. (2003)Roulet et al.( 2007)

    C g

    a

    150

    200

    m-2

    yr-1

    ) Nilsson et al. (2008)Dinsmore et al. (2010)Flanagan et al. (2010)L d (2009)

    0

    50

    100

    flux

    (g C

    Lund (2009)Jac.-Kor. (2009)

    C lo

    ss

    100

    -50

    0C

    -100NEP CH4 DOC Precip Total C

  • Page 6

    • LAI and pH affect both GPP and NEEGPP i bl th R

    Understanding drivers of Net Ecosystem Exchange

    • GPP more variable than Re• Overall: peatland type not a good predictor of NEE

    After Lafleur, 2009

  • Page 7

    • CH4 emissions highly variable

    Understanding Controls over CH4 emissionsCH4 emissions highly variable

    • Winter emissions contributing about 10% of the annual emissions

    • Spatial ‘hotspots’ Lafleur, 2009

    1000Fort Simpson NWT Schefferville QCThompson MB Clay Belt ONFinland S. Hudson Bay LowlandChurchill, MN Schefferville QCDorset ON Kejimkujik NSRiviere du Loup QC Shippagan NB

    B

    WTD a key factor in CH4 emissions

    10

    100

    ux (m

    g m

    -2 d

    -1)

    Riviere du Loup QC Shippagan NBMer Bleue ON Radisson QC

    4(depth of oxic and anoxic parts of the peat)Different intercepts : mean or base rate

    1

    10

    Aver

    age

    CH

    4 fl

    Mer Bleue

    pof CH4 emission controlled by other factors (vegetation, mean climate, etc.)

    after Moore TR, unpub.

    0.1-60 -50 -40 -30 -20 -10 0

    , p

    Average water table position (cm)

  • Page 8

    Carbon is also lost in dissolved form:

    DOC losses from peatlands range from 100%

    DOC export is controlled by 1) production in the peat profile and 2) discharge (Q):

    • variations in flux at a given peatland are largely determined by Q

    • differences among peatlands in similar hydrologic settings are production related

  • Page 9

    Peatlands Drainage: what happens

    GPP G iRe - Ecosystem Respiration

    NEE = GPP - Re

    GPP – Gross primaryproductivity (CO2)

    Plant respiration(CO2)

    Soil respiration(CO2)

    Methane flux

    vascular plants

    Methane flux(CH4)

    moss

    water table

    methane oxidation Acrotelm

    Peat/soilmethanogenesis

    Catotelm

    NEP = - NEE Strack and Waddington, 2007

  • Page 10

    I t i f t

    Intensity of post-drainage utilization varies

    Intensive forestry

    Pasture

    Cropping

    Peat extraction

  • Page 11Degraded peatlands: losses of functionsNon-functional acrotelm: Loss of peat hydraulic properties

    Price and Whitehead, 2004

    Erratic water table regime : drying and rewetting episodes

    Persistent source of CO2 fluxes t t h (100% 400% f

    McNeil and Waddington, 2003

    to atmosphere (100% - 400% of pristine) Waddington et al., 2002

    Waddington et al 2008

    Little re-colonization by Sphagnum mosses

    Waddington et al., 2008Quinty and Rochefort, 2003

  • Page 12

    A peatland may not restore on its own

    ‘Natural’ recolonization of degraded peatlands is slow, and vegetation establishment dominated by vascular vegetation (herbs and shrubs) with poor moss colonization

    Rewetting reduces Re but does not stabilize WT fluctuations if f ti l l i i i

    (herbs and shrubs), with poor moss colonization Poulin et al., 2005Waddington et al., 2008

    Restoring C sink function involves water table regulation by

    functional moss layer is missingWaddington and Day, 2007

    Post-mining restoration techniques have been developed and fi ld t t d f ti l t l d C t ti f ti

    Restoring C sink function involves water table regulation by living moss layer (acrotelm)

    field tested: functional acrotelm and C sequestration function re-established within ~ one decade.

    Lucchese et al., 2010

  • Page 13

    Contrasting GHG dynamics of Peatlands in different statesdifferent states

    Pristine peatlands : long-term C sequestration and climate cooling effect; Re suppression in anoxic zone; hydraulic properties of moss layer key factor in WTD regulation; climate and vegetation controls on NEE and CH4

    Degraded peatlands : drained, with moss layer affected to various degrees by subsidence, compaction, removal. High Re sustained over decades.

    Re-wetted peatlands : reduction in Re, WT subject to high fluctuations if not regulated (climate sensitive), harsh environment for moss re colonizationfor moss re-colonization

    Restored peatlands : C sequestration function re-established through a functional acrotelm.

  • Page 14

    Contrasting GHG dynamics of Peatlands in different States

    Pristine Degraded Re-wetted Restored

    States

    Pristine Degraded Re wetted Restored

    Vegetation & peat

    Intact moss cover and peat

    structure

    No moss; peat compaction &

    subsidence

    Little or no moss

    Re-established moss layer

    ctio

    ns

    Hydrology

    structure

    WTD fluctuation

    subsidence

    WTD highly fluctuating –

    WTD highly fluctuating – if

    WTD and acrotelm

    Func regulated by

    mossclimate sensitive not regulated fluctuations

    regulated

    C exchange GEP > Re & Re dominates; Re smaller; GEP>Re; CH4

    NEP Long-term C C source to C source to net C sink

    gmore variable GEP 0

    e ;CH4 loss larger

    GEP Re; CH4possibly larger

    gsink atmosphere atmosphere

    net C sink

  • Page 15

    Vegetation influences restoration pathway: what are the restoration objectives?what are the restoration objectives?

    RehabilitationTo re-establish the productivity and some, but not necessarily all,of the plant and animal species thought to be originally presentat a site. Ex: re-establish C sink through perennial, vascular vegetation

    RestorationR t bli hi th d t t d ti it d iRe-establishing the presumed structure, productivity and speciesdiversity that was originally present at a site that has beendegraded, damaged or destroyed. In time, the ecological processesand functions of the restored habitat will closely matchand functions of the restored habitat will closely matchthose of the original habitat. Ex: re-establish C sink and hydrological regulation by moss layer

    Nelleman and Corcoran 2010; FAO 2005.

  • Page 16

    Improved estimation of anthropogenic emissions and removals in peatlands involves:emissions and removals in peatlands involves:

    Including key elements of C budget: NEE, CH4, DOC

    Understanding the state of peatlands and h f ti ff t dhow functions are affected

    Determine restoration pathwayDetermine restoration pathway

  • Page 17

    ReferencesBl i D d L fl P 2010 S i d d ti ti f tl d i i IPCC E t ti WMO G 20 O t b 2010Blain D. and Lafleur P. 2010 Science advances and estimation of wetland emissionsIPCC Expert meeting WMO Geneva, 20 October 2010

    FAO. 2005 Helping Forests Take Cover. RAP Publication. 2005/13. /www.fao.org/docrep/008/ae945e/ae945e05.htm.

    Jackowicz-Korczynski, M. 2009. Land-atmosphere interactions at a subarctic palsa mire. Unpublished Ph.D. thesis, Lund University, Lund Sweden, 102 p.

    Lafleur, P.M. 2009. Connecting Atmosphere and Wetland: Trace Gas exchange. Geography Compass, 3/2, 560–585.

    Lucchese, M.C., Waddington, J.M., Poulin, M., Pouliot, R., Rochefort, L., and Strack, M. 2010. Organic matter accumulation in a restored peatland: g g pEvaluating restoration success. Ecological Engineering, 36, 482–488.

    Lund, M. 2009. Peatlands at a Threshold. Unpublished Ph.D. thesis, Lund University, Lund Sweden, 163 p.

    Lund, M., Lafleur, P.M., Roulet, N.T., Lindroth, A., Christensen, T.R., Aurela, M., Chojnicki, B.H., Flanagan, L.B., Humphreys, E.R., Laurila, T., Oechel, W.C., Olejnik, J., Rinne, J., Schubert, P. and Nilsson, M.B. 2010. Variability in exchange of CO2 across 12 northern peatland and tundra sites. Global Change Biology, 16, 2436–2448.

    McNeil, P. and Waddington, J.M. 2003. Moisture controls on Sphagnum growth and CO2 exchange on a cutover bog. Journal of Applied Ecology, 40 (2), 354–367.

    Nellemann, C., Corcoran, E. (eds). 2010. Dead Planet, Living Planet – Biodiversity and Ecosystem Restoration for Sustainable Development. A Rapid Response Assessment. United Nations Environment Programme, GRID-Arendal. Birkeland Trykkeri AS, Norway.

    P li M R h f L Q i F L i C 200 S i f i d l d i E C d C di J l f B 83 39Poulin, M., Rochefort, L., Quinty, F., Lavoie, C 2005. Spontaneous revegetation of mined peatlands in Eastern Canada. Canadian Journal of Botany 83, 539-557.

    Price, J.S. and Whitehead, G.S. 2004. The influence of past and present hydrological conditions on Sphagnum recolonization and succession in a block-cut bog, Québec. Hydrological Processes, 18 (2), 315–328.

    Quinty, F. and Rochefort L. 2003. Peatland Restoration Guide, second edition. Canadian Sphagnum Peat Moss Association and New Brunswick Department f N t l R d E Q éb Q ébof Natural Resources and Energy. Québec, Québec.

    Strack, M. (ed.) 2008. Peatlands and Climate Change . International Peat Society, Saarijärven Of fset Oy, Saarijärvi, Finland.

    Waddington, J.M., Warner, K.D., and Kennedy, G.W. 2002. Cutover peatlands: A persistent source of atmospheric CO2, Global Biogeochemical Cycles, 16(1), 1002.

    Waddington J M and Day S M 2007 Methane emissions from a peatland following restoration Journal of Geophysical Research G:Waddington, J.M. and Day, S.M. 2007. Methane emissions from a peatland following restoration. Journal of Geophysical Research G: Biogeosciences, 112 (3), art. no. G03018.

    Waddington, J.M., Tóth, K., Bourbonniere, R. 2008. Dissolved organic carbon export from a cutover and restored peatland. Hydrological Processes, 22 (13) 2215–2224.

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Understanding Anthropogenic Impact on Peatlands GHGs Dominique Blain, PhD Dominique Blain, PhD IPCC TFI Side Event M iti H t l B Maritim Hotel, Bonn 8 June 2011 Drawing from Quinty and Rochefort, 2003
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