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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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Page 1: Understanding Anthropogenic Impact on Peatlands GHGs · 2011. 6. 9. · Understanding Anthropogenic Impact on Peatlands GHGs Dominique Blain, PhD IPCC TFI Side Event i HMi BtltMaritim

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: Understanding Anthropogenic Impact on Peatlands GHGs · 2011. 6. 9. · Understanding Anthropogenic Impact on Peatlands GHGs Dominique Blain, PhD IPCC TFI Side Event i HMi BtltMaritim

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

Page 3: Understanding Anthropogenic Impact on Peatlands GHGs · 2011. 6. 9. · Understanding Anthropogenic Impact on Peatlands GHGs Dominique Blain, PhD IPCC TFI Side Event i HMi BtltMaritim

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 4: Understanding Anthropogenic Impact on Peatlands GHGs · 2011. 6. 9. · Understanding Anthropogenic Impact on Peatlands GHGs Dominique Blain, PhD IPCC TFI Side Event i HMi BtltMaritim

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

R E t R i ti

NEE = GPP - Re78 ±59

413 ±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 5: Understanding Anthropogenic Impact on Peatlands GHGs · 2011. 6. 9. · Understanding Anthropogenic Impact on Peatlands GHGs Dominique Blain, PhD IPCC TFI Side Event i HMi BtltMaritim

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: Understanding Anthropogenic Impact on Peatlands GHGs · 2011. 6. 9. · Understanding Anthropogenic Impact on Peatlands GHGs Dominique Blain, PhD IPCC TFI Side Event i HMi BtltMaritim

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: Understanding Anthropogenic Impact on Peatlands GHGs · 2011. 6. 9. · Understanding Anthropogenic Impact on Peatlands GHGs Dominique Blain, PhD IPCC TFI Side Event i HMi BtltMaritim

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: Understanding Anthropogenic Impact on Peatlands GHGs · 2011. 6. 9. · Understanding Anthropogenic Impact on Peatlands GHGs Dominique Blain, PhD IPCC TFI Side Event i HMi BtltMaritim

Page 8

Carbon is also lost in dissolved form:

DOC losses from peatlands range from <5 to 40 g C m-2 yr-1

DOC as a percent of NEP range averages from 5% to 70%;DOC as a percent of NEP range averages from 5% to 70%; in individual years it can be >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: Understanding Anthropogenic Impact on Peatlands GHGs · 2011. 6. 9. · Understanding Anthropogenic Impact on Peatlands GHGs Dominique Blain, PhD IPCC TFI Side Event i HMi BtltMaritim

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: Understanding Anthropogenic Impact on Peatlands GHGs · 2011. 6. 9. · Understanding Anthropogenic Impact on Peatlands GHGs Dominique Blain, PhD IPCC TFI Side Event i HMi BtltMaritim

Page 10

I t i f t

Intensity of post-drainage utilization varies

Intensive forestry

Pasture

Cropping

Peat extraction

Page 11: Understanding Anthropogenic Impact on Peatlands GHGs · 2011. 6. 9. · Understanding Anthropogenic Impact on Peatlands GHGs Dominique Blain, PhD IPCC TFI Side Event i HMi BtltMaritim

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: Understanding Anthropogenic Impact on Peatlands GHGs · 2011. 6. 9. · Understanding Anthropogenic Impact on Peatlands GHGs Dominique Blain, PhD IPCC TFI Side Event i HMi BtltMaritim

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., 2005

Waddington 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: Understanding Anthropogenic Impact on Peatlands GHGs · 2011. 6. 9. · Understanding Anthropogenic Impact on Peatlands GHGs Dominique Blain, PhD IPCC TFI Side Event i HMi BtltMaritim

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: Understanding Anthropogenic Impact on Peatlands GHGs · 2011. 6. 9. · Understanding Anthropogenic Impact on Peatlands GHGs Dominique Blain, PhD IPCC TFI Side Event i HMi BtltMaritim

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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: Understanding Anthropogenic Impact on Peatlands GHGs · 2011. 6. 9. · Understanding Anthropogenic Impact on Peatlands GHGs Dominique Blain, PhD IPCC TFI Side Event i HMi BtltMaritim

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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: Understanding Anthropogenic Impact on Peatlands GHGs · 2011. 6. 9. · Understanding Anthropogenic Impact on Peatlands GHGs Dominique Blain, PhD IPCC TFI Side Event i HMi BtltMaritim

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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: Understanding Anthropogenic Impact on Peatlands GHGs · 2011. 6. 9. · Understanding Anthropogenic Impact on Peatlands GHGs Dominique Blain, PhD IPCC TFI Side Event i HMi BtltMaritim

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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