Understanding Anthropogenic
Impact on Peatlands
GHGs

Dominique Blain, PhD
IPCC TFI Side Event
M iti Hotel,Maritim
H t l B
Bonn8 June 2011

Drawing from Quinty and Rochefort, 2003

Page 2

A Proposed
Pd ApproachAh Measuring GHG fluxes Understanding drivers of GHG dynamics
 Understanding GHG dynamics in degraded,

rewetted 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 veryuncertain).

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

Page 4

Measuring GHG fluxes in northern peatlands (g C m-2 yr-2)
78 ±59 NEE = GPP - Re

GPP – Gross primary
productivity (CO2)491 ±130413 ±92
Re - Ecosystem
Et
RRespiration
i tiPlant respiration((CO2)

Soil respiration((CO2)

8 ±7
Methane flux
(CH4)

vascular plantsmossmethaneoxidationwater table
Peat/soil

NEP = - NEE
Blain & Lafleur, 2010

methanogenesis

20 ±12Page 5

Compilation of annual measured C budgets forpeatland sites
 C = CO2-C + CH4-C + DOC + Cppt
300
Roulet et al.( 2007)

200

Nilsson et al. (2008)

C gain250

Dinsmore et al. (2010)

150

Flanagan et al. (2010)100

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

500C loss-2-1

C flux (g C m yr )Worrel et al. (2003)

-50
-100
100
NEP

CH4DOC

PrecipTotal C

Understanding drivers of Net Ecosystem Exchange• LAI and pH affect both GPP and NEE• GPP more variable
i bl thanth Re• Overall: peatland type not a good predictor of NEE

After Lafleur, 2009

Page 6

Understanding Controls over CH4 emissions

Page 7• CH4 emissions highly variable• Winter emissions contributing about 10% of the annual emissions• Spatial ‘hotspots’

Lafleur, 2009

Fort Simpson NWTThompson MBFinland
Churchill, MN
Dorset ON
Riviere du Loup QC
Mer Bleue ON

Schefferville QC
Clay Belt ON
S. Hudson Bay Lowland
Schefferville QC
Kejimkujik NS
Shippagan NB
Radisson QC

B

WTD a key factor in CH4 emissions(depth of oxic and anoxic parts of thepeat)

100-2-1

Average CH4 flux (mg m d )1000

Different intercepts
p : mean or base rateof CH4 emission controlled by otherfactors (vegetation, mean climate, etc.)

10Mer Bleue

1after Moore TR,, unpub.
p0.1
-60

-50

-40

-30

-20

Average water table position (cm)-100

Carbon is also lost in dissolved form:

Page 8

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%;in individual years it can be >100%
DOC export is controlled by 1) production in the peat profileand 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 9Peatlands Drainage: what happens
NEE = GPP - Re

GPP – GrossG
primaryi
productivity (CO2)

Re - Ecosystem Respiration
Plant respiration(CO2)

Soil respiration(CO2)
Methane flux
(CH4)

vascular plantsmossmethaneoxidationwater table
Peat/soil

NEP = - NEE

Acrotelmmethanogenesis

Strack and Waddington, 2007

CatotelmIntensity of post-drainage utilization variesI t
Intensivei forestryftPasture
Cropping
Peat extraction

Page 10Degraded peatlands: losses of functions
Non-functional acrotelm:
Loss of peat hydraulic properties
Price and Whitehead, 2004

Erratic water table regime : drying andrewetting episodes
McNeil and Waddington, 2003

Persistent source of CO2 fluxes
t atmospheretoth(100% - 400% offpristine)
Waddington et al., 2002
Little re-colonization bySphagnum mosses
Waddington et alal., 2008
Quinty and Rochefort, 2003

Page 11A peatland may not restore on its own‘Natural’ recolonization of degraded peatlands is slow, andvegetation establishment dominated by vascular vegetation(herbs and shrubs),shrubs) with poor moss colonization Poulin et al., 2005
Waddington et al., 2008

Rewetting reduces Re but does not stabilize WT fluctuations ifffunctionaltil moss llayer iis missing
i i
Waddington and Day, 2007

Restoring C sink function involves water table regulation byliving moss layer (acrotelm)
Post-mining restoration techniques have been developed andfi ld tested:fieldt t d functional
ftil acrotelm
t l andd C sequestrationt ti ffunctionti
re-established within ~ one decade.
Lucchese et al., 2010

Page 12

Contrasting GHG dynamics of Peatlands in
different states
Pristine peatlands : long-term C sequestration and climate
cooling effect; Re suppression in anoxic zone; hydraulic propertiesof 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 highfluctuations if not regulated (climate sensitive), harsh environment
for moss rere-colonizationcolonization
Restored peatlands : C sequestration function re-establishedthrough a functional acrotelm.

Page 13

Page 14

Contrasting GHG dynamics of Peatlands in different States
StatesPristine

Funcctions

Intact moss
Vegetation cover and peat
& peatstructure
Hydrology

DegradedRe-wetted
Rewetted

RestoredNo moss; peatcompaction &subsidence

Little or nomoss

Re-establishedmoss layer

WTD
WTD highly
WTD highly
fluctuation
fluctuating –fluctuating – ifregulated by climate sensitive not regulatedmossC exchange
g GEP > Re &more variable

Re dominates;
GEP 0NEP

C source toatmosphereLong-term
gCsink

WTD andacrotelm
fluctuations
regulated

Re smaller;;
GEP>RGEPRe; CH4CH4 loss larger possibly larger
C source toatmosphere

net C sink

Page 15Vegetation influences restoration pathway:
what are the restoration objectives?

Rehabilitation
To re-establish the productivity and some, but not necessarily all,of the plant and animal species thought to be originally present
at a site. Ex: re-establish C sink through perennial, vascular vegetation
Restoration
RRe-establishingt bli hi theth presumed
d structure,t tproductivity
d ti it andd species
idiversity that was originally present at a site that has been
degraded, damaged or destroyed. In time, the ecological processes
and functions of the restored habitat will closely match
those of the original habitat. Ex: re-establish C sink and hydrologicalregulation by moss layer
Nelleman and Corcoran 2010; FAO 2005.

Page 16

Improved estimation of anthropogenic
emissions and removals in peatlands involves:
Including key elements of C budget: NEE,CH4, DOC
Understanding the state of peatlands andhhowffunctions
tiare affected
ff t dDetermine restoration pathway

Page 17References
Bl i D.
Blain
D andd Lafleur
L flPP. 2010 Science
S iadvances
dandd estimation
ti ti off wetland
tl d emissionsIPCC
i i
IPCC E
Expertt meeting
ti WMO GGeneva, 20 O
Octobert b 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,gJ.M., Poulin, M., Pouliot, R., Rochefort, L., and Strack, M. 2010. Organic
gmatter accumulation in a restored ppeatland:Evaluating 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
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Quinty,iFF., L
Lavoie,i C 2005.
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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
off NaturalN t l Resources
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ébStrack, 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, JJ.M.
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restoration. Journal of Geophysical Research G:
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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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