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CHAPTER 3

CROSS-CUTTING GUIDANCE ON
REWETTED PEATLANDS AND
ORGANIC SOILS
Contents

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Cross-cutting guidance on REWETTED PEATLANDS AND organic soils.................................................. 38

3.1

Introduction ........................................................................................................................................... 3

9

3.2

Greenhouse Gas Emissions and Removals from Re-wetted Peatlands and Organic Soils .................... 4

10

3.2.1

CO2 Emissions and Removals from Re-wetted Peatlands and Organic Soils ................................... 4

11

3.2.2

CH4 Emissions and Removals from Re-wetted Peatlands and Organic Soils ................................. 10

12

3.2.3

N2O Emissions and Removals from Re-wetted Peatlands and Organic Soils ................................. 12

13

3.3

Completeness, Time series, consistency, and QA/QC ......................................................................... 13

14

3.3.1

Completeness .................................................................................................................................. 13

15

3.3.2

Developing a consistent time series ................................................................................................ 13

16

3.3.3

Quality Assurance and Quality Control (QA/QC) .......................................................................... 14

17

3.3.4

Reporting and Documentation ........................................................................................................ 14

18

3.4

Basis for future methodological development ...................................... Error! Bookmark not defined.

19

Annex 3A.1

Estimation of default emission factors for CO2-C in rewetted peatlands and organic soils ........ 18

20

Annex 3A.2

Estimation of default emission factors for CO2-DOC in rewetted peatlands and organic soils .. 19

21

Annex 3A.3

Estimation of default emission factors for CH4-C in rewetted peatlands and organic soils ........ 20

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Equations27

Equation 3.1 CO2-C EMISSIONS/REMOVALS FROM REWETTED PEATLANDS AND ORGANIC SOILS 4

28

Equation 3.2 ............................................................................................................................................................ 529

Equation 3.3 ............................................................................................................................................................ 830

Equation 3.4 .......................................................................................................................................................... 1031

Equation 3.5 .......................................................................................................................................................... 1032

Equation 3.6 .......................................................................................................................................................... 13

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Figures34

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Figure 3.1 Decision tree to estimate CO2-C emissions/removals from rewetted peatlands and organic soils.
7

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Figure 3A.1 ................................................................................................................................................... 18

Tables38

39

Table 3.1 ......................................................................................................................................................... 440
41

Table 3.2 Emission Factors (EFCO2 rewetted , in tonnes CO2-C ha-1 yr-1) for CO2-C (± Standard Deviation) for
Rewetted Peatlands and Organic Soils .................................................................................................... 84243

Table 3.3 Default DOC emission factors (EFDOC_rewetted in tonnes CO2-C ha-1 yr-1) for re-wetted peatlands
and organic soils (values in parentheses represent uncertainty ranges)................................................... 944
45

Table 3.4 Default emission factors for CH4 from rewetted peatlands and organic soils (all values in kg CH4C ha-1 yr-1).............................................................................................................................................. 1246
47

Table 3A.1 DOC concentration (above) or flux (below) comparisons between drained and re-wetted peats.............................................................................................................................................................. 19

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3 CROSS-CUTTING GUIDANCE ON REWETTEDPEATLANDS AND ORGANIC SOILS

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3.1

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What is rewetting, restoration, rehabilitation and how they a ffect GHG

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57

Wetlands are lands characterised by water saturation of the soil dominating hydrological and biogeochemical
processes. Rewetting is the action of raising the water table on drained land to re-establish such conditions, e.g.
by blocking drainage ditches or disabling pumping facilities.

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Restoration is the permanent re-establishment, on formerly drained sites, of hydrological and biogeochemical
processes characteristics of saturated soils, as well as of the vegetation cover that pre-dated the drainage of thesesoils. Restoration necessarily includes the re-wetting of formerly drained areas.

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Rehabilitation or reclamation is the re-establishment, on formerly drained sites, of some of – but not necessarily
all - the hydrological, biogeochemical and ecological processes and functions that characterized pre-drainage
conditions. As such, rehabilitation can involve a large variety of practices on formerly drained peatlands ororganic soils, which may or may not include re-wetting.

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Scope of this guidance: wetland types covered, gases, pools, relev ant classifiers

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In keeping with the recommendations in chapter 7, volume 4, 2006 IPCC Guidelines, GHG emissions from rewetted and restored peatlands or organic soils are quantified as fluxes rather than C stock changes. Likewise,
carbon emissions or removals in the form of CO2 will be described as CO2-C, and when they occur in the formof CH4 as CH4-C.

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Contrary to most ecosystems, the distinction between C pools in some wetlands can be difficult, especiallybetween the dead organic matter and soil pools. For example, the dead portion of moss species characteristics ofmany northern peatlands could be included in the dead organic matter or soil pool. Moreover, the default
emission factors in this chapter were all derived from flux measurements; these fluxes, when measured overmoss-covered or grass-covered peatlands or organic soils, integrate all C pools. In all cases the guidance in thischapter will clarify which C pools are included in default EFs. Peatlands and organic soils can also support
perennial woody vegetation; the default approach will treat this carbon pool as in the remainder of the 2006 GLs.

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Evidence of successfully re-wetted peatlands or organic soils in tropical or sub-tropical regions was insufficient
to provide a sound basis for the development of default EFs. Specifically, no evidence could be found of successin raising the water table to the level observed in pristine peatlands. As a result, flux measurements from pristine
peatlands in tropical or sub-tropical climates could be used as a proxy for EF on re-wetted peatlands in theseregions and only provided for CO2 as a basis for future methodological development. The assumption remainsthat GHG emissions will respond to re-wetting; however countries in tropical and sub-tropical regions where
significant areas of peatlands or organic soils have been re-wetted should are encouraged to develop sciencebased, documented, country-specific emission factors for both CO2 and CH4 emissions.

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INTRODUCTION

For the purpose of this chapter, re-wetting, restoration and rehabilitation are understood as follows:

The guidance provided in this chapter will include re-wetting and restoration of peatlands and organic soils,
excluding other forms of rehabilitation or reclamation, whose outcome is more variable and site-specific. This
chapter seeks to avoid repeating guidance already provided, hence wherever appropriate will refer to alreadyexisting guidance in these Guidelines. Table 3.1 summarizes the coverage of this chapter.

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TABLE 3.1
Peat type

Bog

Fen

Tropical peat

CO2

Section 3.2.1

Section 3.2.1-

CH4

Section 3.2.2

Section 3.2.2-

N2O

Section 3.2.3

Section 3.2.3

-

CO2

-

-

Appendix

CH4

-

-

Section 3.4.1

N2O

-

-

Section 3.4.2

Climate region
Boreal/temperate

Tropical

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How to use guidance in this chapter and relationship to reporting categories

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3.2

GREENHOUSE GAS EMISSIONS ANDREMOVALS FROM RE-WETTED PEATLANDSAND ORGANIC SOILS

3.2.1

CO 2 Emissions and Removals from Re-wetted
Peatlands and Organic Soils

The post-rewetting land use of peatlands and organic soils can vary according to national circumstances.
Depending on the management practices and the national land-use classification, it may be more appropriate toreport the GHG estimates of re-wetted peatlands or organic soils under forest land, cropland, grassland or
wetlands. It is therefore recommended to consider this guidance as potentially common to several reporting
categories. Because the functioning of these ecosystems have already been deeply altered, reporting re-wetted
peatlands or organic soils as unmanaged land is not consistent with good practice.

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CO2-C emissions/removals from re-wetted peatlands and organic soils have the following components:

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EQUATION 3.1
CO2-C EMISSIONS/REMOVALS FROM REWETTED PEATLANDS AND ORGANIC
SOILS
CO2-Crewetted = CO2-Csoil + CO2-Cveg + CO2-Cwoody biomass + CO2-CDOM + CO2-CDOC

107

Where:

108

CO2-Crewetted = CO2-C emissions/removals from re-wetted peatlands and organic soils, tonnes C yr-1

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CO2-Csoil =CO2-C emissions from the soil, tonnes C yr-1

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CO2-Cveg = net CO2-C emissions by, or removals from re-wetted vegetation, tonnes C yr-1

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CO2-Cwoody biomass = net CO2-C emissions by, or removals from perennial woody biomass, tonnes C yr-1

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CO2-CDOM = CO2-C emissions from dead organic matter, tonnes C yr-1

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CO2-CDOC = CO2-C emissions from dissolved organic carbon, tonnes C yr-1

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CO2-Csoil is produced during the decomposition of the soil/peat by heterotrophic organisms and is controlledstrongly by oxygen availability within the soil. CO2-Cveg is the net result of two processes by the vegetation
component: photosynthesis (CO2 uptake) and autotrophic respiration (CO2 emissions).

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CO2-CDOM is produced from the decomposition of dead organic matter, such as litter, root exudates and coarse
woody debris.

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The default EFs provided in this section capture the components CO2-Csoil, CO2-Cveg and CO2-CDOM together
rather than C stock changes by pool. These default EFs are developed from annualized flux measurements,
ensuring that there is no seasonal bias.

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This chapter does not provide default methodologies for estimating C stock changes in perennial woody biomasson re-wetted peatlands or organic soils. When the vegetation on re-wetted sites consists of perennial woody
biomass, guidance in vol 4, chapter 2, 4, 5 and 6 should be used.

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CO2-CDOC is produced from the decomposition of dissolved organic carbon (DOC) lost via aquatic pathways.
DOC is the major component of waterborne carbon export, Particulate Organic Carbon (POC), dissolved CO2
and Dissolved Inorganic Carbon (DIC) being the other minor components (Billett et al. 2004, Billett and Moore
2008, Worrall et al. 2009, Billett et al. 2010, Dinsmore et al. 2010). Re-wetting especially of non-re-vegetatedcutaway peatlands could lead to high POC export which can be converted to CO2. However, POC is likely to be
simply translocated from the re-wetted peatlands to other stable carbon stores, such as freshwater or marine
sediments and may not lead to CO2 emission. Due to the uncertain fate of POC export, no estimation
methodology is presented in this text. Finally, dissolved CO2 or DIC emissions form a relatively small
component of total land-atmosphere CO2 exchange.

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CHOICE OF METHOD

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Tier 1The decision tree in Figure 3.1 presents guidance in the selection of the appropriate tier for the estimation ofgreenhouse gas emissions from re-wetted peatlands and organic soils. Under Tier 1, the nationally derived areaof rewetted peatlands and organic soils is multiplied by an emission factor, which is disaggregated by climate
region and peatland type (Equation 3.2).

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EQUATION 3.2
(

)

(

)

Where:

147

CO2-Crewetted = CO2-C emissions/removals from rewetted peatlands and organic soils, tonnes C yr-1)

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Arewetted = total area of peatlands and organic soils that have been rewetted, ha

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EFCO2 rewetted = CO2-C emission factor for rewetted peatlands and organic soils, tonnes C ha-1 yr-1

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EF DOC-rewetted = CO2-C emission factor for DOC from a re-wetted peatlands and organic soils tonnes C ha1
yr-1

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Tier 2

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A Tier 2 approach to quantify DOC fluxes may follow the Tier 1 methodology provided above, but should utilise
country-specific information where possible to refine the emission factor used as well as the conversion factor.
Refinements could include:

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Tier 2 calculations use country-specific emission factors and parameters, spatially disaggregated to reflect
regionally important practices and dominant ecological dynamics. It may be appropriate to sub-divide activity
data and emission factors according to the present vegetation composition (Couwenberg et al. 2011) andprevious land use history. CO2-C fluxes during the time period immediately following rewetting (0-5 years) havebeen shown to be significantly different to those observed 5 years or more after rewetting (Annex or in Guidance
for future methodology to be provided). Countries are encouraged to develop more detailed EFs for rewetted
peatlands and organic soils by the use of a 5 year “transition period”.

(i)

Use of country-level measurements from re-wetted peatlands with various restoration
techniques and initial status. Direct measurements of DOC fluxes from re-wetted peats could replace
the DOCFLUX_NATURAL values used in the Tier 1 default approach, i.e. replacing the default assumptionthat re-wetted peatlands revert to pre-drainage DOC fluxes. Differences between pre-drainage and rewetted DOC fluxes could occur due to the presence or absence of vegetation on re-wetted sites; if rewetted vegetation composition differs from natural peatlands, or due to factors associated with peat
restoration techniques, such as the creation of pools behind dams, or the application of mulch tosupport vegetation re-establishment, which has been shown to have a direct impact on DOC fluxes

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(Strack et al. 2011), or the use of biomass to infill ditches. The use of an initial EF (between 0 and 5
years after restoration) and 5 years or more after rewetting (as per CO2 emissions) is likely to be
applied given the dynamics of the vegetation colonisation/development.

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(ii)

Use of country-level measurements from natural peatlands to obtain accurate values of
DOCFLUX_NATURAL for that country, for example by developing specific values for raised bogs versus
fens, or for blanket bogs under different precipitation levels (see equation used at the bottom of Table
3.2).

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(iii)

Use of alternative values for FDOC-CO2 where evidence is available to indicate that a different
proportion of DOC exported from re-wetted peatlands and organic soils is transferred to stable longterm carbon stores, such as lake or marine sediments.

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Tier 3
A Tier 3 approach involves a comprehensive understanding and representation of the dynamics of CO2-C
emissions and removals on re-wetted peatlands and organic soils, including the effect of site characteristics, peat
type and depth, vegetation composition, soil temperature and mean water table depth (WTD). These parameters
could also be used to describe DOC release using process-based models. A Tier 3 approach might also include
the entire DOC export from re-wetted sites and consideration of the temporal variability in DOC release in theyears following re-wetting (e.g. initial period of less than 5 years) which will be also dependent on therestoration techniques used.

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Figure 3.1

Decision tree to estimate CO 2 -C emissions/removals from rewetted peatlands
and organic soils.
Start

Is detailed
information available
on re-wetting of peatlands
or organic soils?

Yes

Estimate emissions using
country specificmethodology and emission
factors (Tier 3).
Box 3: Tier 3

No

Are historicaland current data
available on the area ofrewetted peatlands andorganic soils?

Yes

Were
domestic studies
done on GHG emissions/removals in rewetted
peatlands and organicsoils?

Yes

Estimate emissions using
default method and country
specific data (Tier 2)

NoNo

Box 2: Tier 2
Are rewetted
peatlands and organic soils
a key category?

Yes

Collect or compile historicaland current data from domestic
or international industry or(non-)government agencies

No

Estimate emissions using default
emission factors and activity
data (Tier 1).

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Box 1: Tier 1

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CHOICE OF EMISSION F ACTORS

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Tier 1
The implementation of the Tier 1 method requires the application of default emission factors EFs provided inTable 3.2, where they are disaggregated by climate region (boreal, temperate) and peatland type (bog, fen).
There is insufficient data available to permit the inclusion of rewetted tropical peatlands at this time. Peatland
type can be inferred from the nutrient status of the peat substrate: e.g. sphagnum peat is characteristic of themore nutrient poor (oligotrophic) bogs and Phragmites peat is common in nutrient rich (minerotrophic) fens.
Countries with significant areas of re-wetted peatlands and organic soils are encouraged to develop domestic
emission factors and develop estimates of emissions and/or removals using Tier 2 or 3 methodologies.

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The derivation of these default emissions factors values is fully described in Annex 3.1. In summary, whileavailable data indicated that CO2 fluxes from natural peatlands and re-wetted peatlands are in both cases
correlated with water table, it was ascertained that this relationship was not significantly different between thetwo ecosystems (except for temperate fens). Therefore CO2 fluxes from natural undrained sites were used inaddition to CO2 fluxes from re-wetted sites in order to provide robust estimation of EFs as shown in Table 3.3. In
the case of temperate fens, available data from re-wetted sites only were used to estimate the EF.

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TABLE 3.2
EMISSION FACTORS (EFCO2 REWETTED , IN TONNES CO2-C HA-1 YR-1) FOR CO2-C (± STANDARD DEVIATION) FOR REWETTEDPEATLANDS AND ORGANIC SOILSBOREALTEMPERATEBOGS (raised and blanket)-0.26 (0.48)-0.52 (1.17)

FENS-0.93 (0.94)+0.72 (3.42)

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EF D O C - r e w e t t e d
Robust data show that natural, undrained peatlands export some DOC and these fluxes increase following
drainage (see Chapter 2). Available data from re-wetted sites suggest that the level of DOC reduction after rewetting equates to the DOC increase after drainage. Consequently, it is assumed that re-wetting leads to areversion to natural DOC flux levels (see Annex 3.2 for explanation). Therefore, to make best use of available
data, EFs for re-wetted peatlands have been calculated according to Equation 3.3:

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EQUATION 3.3
EFDOC re-wetted = DOCFLUX_NATURAL * FDOC-CO2
Where:

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EF DOC-Re-wetted = emission factor for DOC from a re-wetted site, tonnes C m-2 yr-1

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DOCFLUX_NATURAL = Flux of DOC from natural (undrained) peatland, tonnes C m-2 yr-1

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FDOC-CO2 = Conversion factor for proportion of DOC converted to CO2 following export from site

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EFDOC-re-wetted values (required in Equation 3.2) are provided in Table 3.3. The DOCFLUX_NATURAL values were
derived based on available data indicating that the rate of DOC export from temperate and boreal raised bogs andfens is positively correlated with water fluxes. A simple schema for deriving values of DOCFLUX_NATURAL as afunction of rainfall was used and provides a separate EF as shown in Table 3.3. This relationship was not
ascertained for blanket bogs, which display higher water fluxes in general and, therefore, a separate category
using all DOC flux values from natural blanket bogs in the literature has been used and associated EF computed.
This was also done separately for tropical peatlands. The derivation of these values is fully described in Annex X.

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An understanding of the ultimate fate of DOC export, i.e. whether it is returned to the atmosphere as CO2 (oreven CH4), is still poor and yet of great significance in terms of GHG reporting. The parameter FDOC-CO2 sets the
proportion of DOC exported from peatlands and organic soils which is ultimately converted to CO2. A value ofzero would coincide with all the DOC export being deposited in stable forms in lake or marine sediments, as thiswould simply represent a translocation of carbon between stable stores, it would not need to be estimated.
However, most data on DOC processing do indicate that a high proportion is converted to CO 2 in headwaters,

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rivers, lakes and coastal seas (see Chapter 2). Therefore, a Tier 1 default FDOC-CO2 value of 90% is proposed, withan uncertainty range of 80-100%.
TABLE 3.3
DEFAULT DOC EMISSION FACTORS (EFDOC_REWETTED IN TONNES CO2-C HA-1 YR-1) FOR RE-WETTED PEATLANDS AND
ORGANIC SOILS (VALUES IN PARENTHESES REPRESENT UNCERTAINTY RANGES)
Peat type

Precipitation regime (mmyr-1)

DOCFLUX_NATURAL(tonnes C m-2 yr -1)

EFDOC_rewetted

< 500

5

5 (3-8)500-70012

10 (7-15)

700-90018

16 (12-21)_

> 900

24

22 (17-36)

Temperate blanket bog

All

21

19 (10-28)

TropicalAll59

53 (38-69)

Temperate/boreal raised
bog/fen aa DOCFLUX_NATURAL values for boreal/temperate raised bogs and fens are calculated from the equation DOCFLUX_NATURAL =(0.0317  Precipitation) – 7.5, in the units shown above, using representative mid-range values of 400, 600, 800 and 1000 mm for each of theclasses shown. This equation may be used to calculate site-specific estimates where actual precipitation values are known.

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Tier 2 and 3
The uncertainty of EFs can be reduced on the basis of spatially disaggregated CO2 flux measurements. Flux
measurements (eddy covariance or chamber methods) should be carried out at temporal resolutions sufficiently
defined to capture as wide a range as possible of the abiotic (e.g. irradiation, soil temperature, WTD) and biotic(e.g. vegetation composition) factors that drive CO2 dynamics in re-wetted peatlands and organic soils.

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Countries where perennial woody biomass plays a significant role in the net CO2-C exchange between re-wetted
peatlands or organic soils and the atmosphere should develop country-specific factors reflecting C stock changes
in this pool under typical management practices. Guidance to this effect can be found in Vol 4, chapters 3-5.

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CHOICE OF ACTIVITY DATA

251
252

All Tiers require data on areas of re-wetted peatlands or organic soils, broken down by climate zone, type of
peatland or organic soils.

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256
257
258

Tier 1

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261
262
263
264
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266

Tier 2 and 3

The default methodology assumes that a country has data on the area of re-wetted peatlands or organic soils andthe type of peatland or organic soils, consistent with the advice above on the selection of emission factors. Data
can be obtained from the peat extraction industry, forestry or agricultural agencies, as well as from government
and non-government sources. Re-wetting plans and land use maps are useful sources of information.
Tier 2 and 3 approaches are likely to involve a more detailed stratification than in Tier 1. This can include further
sub-divisions based on time since re-wetting, previous land use history and current land use as well as vegetation
composition. It is good practice to further sub-divide default classes based on empirical data that demonstrates
significant differences in CO2-C fluxes among the proposed categories. For application of a direct measurementbased inventory in Tier 3, similar or more detailed data on the combinations of climate, soil, topographic andmanagement data are needed, relative to the Tiers 1 and 2 methods, but the exact requirements will depend on
the measurement design and country-specific circumstances.

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CH4 Emissions and Removals from Re-wetted
Peatlands and Organic Soils

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CH4 emissions and removals from the soils of re-wetted peatlands and organic soils result from 1) emissions or
removals resulting from the balance between CH4 production and oxidation in the soil column and 2) emissionof CH4 produced by the combustion of organic matter during fire (Equation 3.4).

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EQUATION 3.4

268

275

3.2.2

Where:

276

CH4-Crewetted = CH4-C emissions from re-wetted peatlands or organic, tonnes C yr-1

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CH4-Csoil = emissions of CH4-C from peatlands or organic soils subject to rewetting, tonnes C yr-1

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CH4-Cbiomass burn = emissions of CH4-C from biomass burning on rewetted peatlands or organic soils,
tonnes C yr-1

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CH4-Csoil burn = emissions of CH4-C from soil or peat burning on rewetted peatlands or organic soils,
tonnes C yr-1

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The default EFs provided in this section will only cover CH4-Csoil. Generic methodologies for estimating CH4emissions from the burning of vegetation, dead organic matter (CH4-Cbiomass burn ) are provided in chapter 2 ofvolume 4, while methodologies specific to vegetation and DOM burning in forest land, cropland, grassland andwetlands are provided in chapters 3-6 of volume 4. When burning occurs, emissions from the burning of soil
should be estimated using country-specific (Tier 2) emission factors.

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292

As noted in Chapter 2, emissions of CH4-C from drainage ditches can be much higher than the surrounding
drained peat fields. Few data are available on CH4-C emissions from ditches of rewetted peatlands and organicsoils and in some cases ditches may be filled during rewetting activities. When ditches remain, countries areencouraged to include estimates of CH4-C ditch emissions using methodology provided in Chapter 2 (Equation
2.X) and country specific emission factors. Table 2.X can also be consulted for guidance on emission factors for
ditches in drained peatlands.

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294
295
296
297
298

As noted in Chapter 2, emissions of CH4-C from drainage ditches can be much higher than the surrounding
drained peat fields. Few data are available on CH4-C emissions from ditches of rewetted peatlands and organicsoils and in some cases ditches may be filled during rewetting activities. When ditches remain, countries areencouraged to include estimates of CH4-C ditch emissions using methodology provided in Chapter 2 (Equation
2.X) and country specific emission factors. Table 2.X can also be consulted for guidance on emission factors for
ditches in drained peatlands.

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CHOICE OF METHOD

301
302

Refer to Figure 3.1 for the decision tree to select the appropriate tier for the estimation of estimate CH4
emissions or removals from rewetted peatland or organic soils.

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304
305

Tier 1The default methodology covers CH4 emissions and removals from rewetted peatlands soils and re-wettedorganic soils (Equation 3.5).

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307

EQUATION 3.5
(
[

308

)
]

Where:

309

CH4-Csoil = methane emissions from the soils of re-wetted peatlands and organic soils, tonnes C ha-1 yr-1

310

Arewetted = total area of peatlands and organic soils that have been rewetted, ha yr-1

311

EFCH4 soil = emission factor from rewetted peatlands or organic soil, kg CH4-C ha-1 yr-1

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Rewetted area should be subdivided by climate zone (boreal or temperate) and appropriate emission factors
applied. The data available at present is insufficient to support the development of default EF for tropical regions.
When information is available on the peatland type, countries are encouraged to further subdivide rewetted area
into bogs and fens, multiply each one by the appropriate emission factor and sum the products for the total CH4emission or removal.

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319
320
321
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323

Tier 2Tier 2 calculations use country-specific emission factors and parameters, spatially disaggregated to reflect
regionally important practices and dominant ecological dynamics. In general, methane fluxes from wet
peatlands are extremely skewed, approaching a log-normal (right-tailed) distribution. This asymmetry towards
rare, but high efflux values causes high mean values compared to the most likely encountered median values.
Countries are encouraged to further scientific understanding of methane effluxes from re-wetted peatland sites,
allowing for more precise estimation.

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329

Methane fluxes from peat and organic soils strongly depend on the depth of the water table, with efflux
increasing steeply from near zero when mean annual water levels stands below -20 cm from the surface, to veryvariable and high values at water levels less than 20 cm from the surface. Variability is even greater on flooded
sites, where both low (Couwenberg & Fritz 2012; Couwenberg et al., 2010) and high (Augustin & Chojnicki
2008; Glatzel et al., 2011) flux values have been observed.

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337

Prior land-use (e.g. agriculture, peat extraction, forestry) can influence CH4 fluxes from re-wetted peatlands ororganic soils. For example, CH4 emissions following the re-wetting of some agricultural land with nutrient
enriched top-soil appear higher compared to average emission factors (Augustin & Chojnicki, 2008; HahnSchöffl et al., 2011; Glatzel et al., 2011) whereas rewetted boreal cutover peatlands may have CH4 emissions
below the average emission factors (Waddington and Day, 2007). It may therefore also be appropriate to
subdivide activity data and emission factors according to previous land-use when this information is available.
The influence of previous land use may diminish over time.

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348

Data on CH4 emissions and removals from rewetted peatlands and organic soils remains relatively sparse,
particularly at locations rewetted for longer than 10 years. Due to the limited number of long-term rewetting
studies, the change in CH4 emissions over time remains unclear. The pattern of changes in CH4 flux with timesince rewetting may be linked to prior land-use. Research on restored cutover peatlands in Canada indicates anincrease in CH4 emissions each year during the first three years post-restoration as the emerging vegetation
cover provides fresh substrate for CH4 production (Waddington and Day, 2007). In contrast, rewetting ofintensive grassland on fen peat suggests that CH4 emissions may decline over time as litter inundated during
rewetting activities is rapidly decomposed in the first few years (Augustin and Joosten 2007). Changes in CH4emissions and removals over time are likely linked to vegetation succession (e.g. Tuittila et al. 2000) and thus
understanding the pattern of emissions over time will likely require the inclusion of vegetation information.

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362

Several studies in both undisturbed and rewetted peatlands indicate the important role that vegetation may playfor providing substrate for CH4 production and for transporting CH4 from the saturated soil to the atmosphere(e.g. Bubier 1995; Shannon et al. 1996; Marnier et al. 2004; Tuittila et al. 2000; Wilson et al. 2007; Dias et al.
2010). Species known to transport CH4 from the soil to the atmosphere include, but are not limited to Calla,
Carex, Cladium, Eleocharis, Equistem, Eriophorum, Glyceria, Nuphar, Nymphaea, Peltandra, Phalaris,
Phragmites, Sagittaria, Scheuchzeria, Scirpus, and Typha (Sebacher et al. 1985, Chanton et al. 1992, Schimel
1995, Shannon et al. 1996, Frenzel & Rudolph 1998, Verville et al. 1998, Yavitt & Knapp 1998, Grünfeld &Brix 1999, Frenzel & Karofeld 2000, Tuittila et al. 2000, Arkebauer et al. 2001, Armstrong & Armstrong 2011,
Askaer et al. 2011). The presence of these aerenchymous shunt species has a marked effect on methane efflux
from peatlands (Couwenberg & Fritz, 2012). Most of the data available at present are from sites that wererewetted only recently when methane fluxes were measured. Countries are encouraged to use methane flux
measurements from longer term rewetted sites and develop nationally specific emission factors that address
vegetation composition (see Couwenberg et al., 2011).

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Tier 3
A Tier 3 approach involves a comprehensive understanding and representation of the dynamics of CH4
emissions on re-wetted peatlands and organic soils, including the representation of interactions between thedominant drivers of CH4 dynamics, as described above.

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CHOICE OF EMISSION F ACTORS

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373
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376

Tier 1
The implementation of the Tier 1 method requires the application of default emission factors EFCH4 soil provided
in Table 3.4, where they are disaggregated by climate region (boreal, temperate) and peatland type (bog, fen).
Available flux data for rewetted tropical peatlands are insufficient for the development of default EFs.
Comparison of hourly flux data suggests that efflux in SE Asian peat swamps (the largest extent of tropicalpeatland) will be much lower than in temperate/boreal regions (Couwenberg et al., 2010). Annex 3.3 provides
more details on the derivation of these default EFs.
TABLE 3.4
DEFAULT EMISSION FACTORS FOR CH4 FROM REWETTED PEATLANDS AND ORGANIC SOILS (ALL VALUES IN KG CH4-C HA-1
-1
YR )Climate zone

EFrewetted

Boreal80 (n= 27)

Temperate

Peatland typeEFrewettedBog

16 (n=12)Fen

162 (n=12)Bog

156 (n=41)Fen

374 (n=63)

Uncertainty

265 (n=104)

Tropical

377
378
379
380

Uncertainty

p.m.

Tier 2 and 3
The uncertainty of emission factors can be reduced by using country specific emission factors for each climatezone and peatland type. It can be further reduced by implementing scientific findings relating CH4 emissions toprior land use, the depth of the water table, vegetation cover and time since re-wetting.

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CHOICE OF ACTIVITY D ATA

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All Tiers require data on areas of re-wetted peatlands or organic soils, broken down by climate zone, type of
peatland or organic soils.

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387

Tier 1The default methodology assumes that a country has data on the area of re-wetted peatlands or organic soils andthe type of peatland or organic soils, consistent with the advice above on the selection of emission factors.

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394

Tier 2 and 3
More sophisticated estimation methodologies will require the determination of monthly averages of the watertable depth; land use and management practices prior to re-wetting; and vegetation composition and thesuccessional changes in vegetation community composition and biomass with time since rewetting. This type of
information can be obtained by long-term monitoring of re-wetted sites under various conditions, and should be
combined with an enhanced understanding of the processes linking CH4 emissions to these factors.

395

397

N2O Emissions and Removals from Re-wetted
Peatlands and Organic Soils

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400
401
402

The emissions of N2O from re-wetted peatlands or organic soils are controlled by the quantity of N available fornitrification and de-nitrification, and the availability of the oxygen required for these chemical reactions. Oxygen
availability is in turned controlled by the depth of the water table. Raising the depth of the water table will cause
N2O emissions to decrease rapidly, and practically completely if the depth of the water table is less than 20cm
below the surface.

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404

Equation 3.6 includes the essential elements for estimating N2O emissions from re-wetted peatlands or organicsoils:

396

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EQUATION 3.6

Where:

408

N2Orewetted = N2O emissions from re-wetted peatlands or organic soils, tonnes N2O yr-1

409

N2Osoil = N2O emissions from the soil pool of re-wetted peatland or organic soils, tonnes C yr-1

410
411

N2Obiomass burn = N2O emissions from biomass burning on rewetted peatlands or organic soils, tonnes
N2O yr-1

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413

N2Osoil burn = N2O emissions from soil or peat burning on rewetted peatlands or organic soils, tonnes N2O
yr-1

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415
416
417
418

This chapter only covers N2Osoil. Generic methodologies for estimating N2O emissions from the burning ofvegetation and dead organic matter are provided in chapter 2 of volume 4 in the existing 2006 GLs, while
methodologies specific to vegetation and DOM burning in forest land, cropland, grassland and wetlands areprovided in chapters 3-6 of volume 4. When burning occurs, emissions from the burning of soil should be
estimated using country-specific (Tier 2) emission factors.

419

Under Tier 1, emissions of nitrous oxides from re-wetted soils are assumed to be insignificant1.

420
421
422
423
424
425
426

At higher tiers, countries are encouraged to examine the pattern of N2O emissions from re-wetted peatlands andorganic soils by climate zone and peat type, in particularly tropical climate. Country specific emission factors
should take into account fluctuations of the water table depth, which controls oxygen availability for nitrification,and previous land use, which may have resulted in top soil enrichment (Nagata et al., 2006; 2010). Caution
should be exerted to avoid double-counting N2O emissions from re-wetted sites that can be directly linked toallochtonous (external) nitrogen input, as these emissions may already be reported as indirect emissions fromanthropogenic N input within the watershed.

427

3.3

COMPLETENESS, TIME SERIES,CONSISTENCY, AND QA/QC

430

3.3.1

Completeness

431
432
433

Complete greenhouse gas inventories will include estimates of emissions from all greenhouse gases emissions
and removals on rewetted and restored peatlands for which default guidance is provided in this chapter, for all
peatland types or organic soils that occur on the national territory.

434
435
436

It is good practice to ensure that all drained peatlands and organic soils on the national territory are alreadyincluded in the national inventory, prior to estimating emissions and removals from rewetted peatlands ororganic soils.

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439
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441

As for all land categories, countries are encouraged to monitor the fate of rewetted and restored peatlands, andavoid double counting emissions reported from lands in various categories. The greenhouse gas balance of rewetted lands with peat or organic soils should include all applicable carbon pools, while avoiding doublecounting between carbon pools, especially if flux-based estimation methodologies are combined with stockchange approaches.

442

3.3.2

443
444
445
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447

General guidance on ensuring time series consistency can be found in Chapter 7 of this Supplement. The
emission and removal estimation method should be applied consistently to every year in the time series, at thesame level of spatial disaggregation. Moreover, when country-specific data are used, national inventory agencies
should use the same measurement protocol (sampling strategy, method, etc.) throughout the time series, or use
documented, unbiased methods to ensure the representativeness and applicability of emission factors.

428
429

1

Developing a consistent time series

Augustin, 2003; Augustin and Chojnicki, 2008; Drösler, 2005; Hendriks et al., 2005; Jungkunst and Fiedler, 2007; Wild etal., 2001, Wilson et al., in press.

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3.3.3

Quality Assurance and Quality Control (QA/QC)

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451
452
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454

Quality assurance/quality control (QA/QC) procedures should be developed and implemented as outlined in
Chapter 7 of this Supplement. It is good practice to develop additional, category-specific quality control andquality assurance activities if higher tier methods are used to quantify emissions and removals from this category.
Where country-specific emission factors are being used, they should be based on high quality experimental data,
developed using a rigorous measurement programme, and be adequately documented, preferably in the peerreviewed, scientific literature.

455

3.3.4

456

EMISSION FACTORS

457
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459

The scientific basis of country-specific emission factors, parameters and models should be fully described anddocumented. This includes describing the input parameters, the derivation of emission factors, parameters andmodels and the sources of uncertainty, as well as justifying their representativeness.

460
461

It is good practice to clearly document the carbon pools that are captured by flux-based emission factors and thecompleteness in terms of pool coverage.

Reporting and Documentation

462
463

ACTIVITY DATA

464
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466
467

Sources of all activity data used in the calculations (data sources, databases and soil map references) should berecorded, plus (subject to any confidentiality considerations) communication with industry. This documentation
should cover the frequency of data collection and estimation, and estimates of accuracy and precision, andreasons for significant changes in activity data.

468
469
470

Information should be provided, for each land-use category, on the proportion of drained and re-wetted areas
with organic soils. Overall, the sum of re-wetted areas with peat or organic soils reported under each land use
categories should equal the total national area of re-wetted peatlands or organic soils.

471
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TREND ANALYSIS

473
474
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476

Significant fluctuations in emissions and removals between years should be explained. A distinction should bemade between changes in activity levels and changes in emission factors, parameters and methods from year toyear, and the reasons for these changes documented. If different emission factors, parameters and methods areused for different years, the reasons for this should be explained and documented.

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References

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481

Alm J., Talanov A., Saarnio S., Silvola J., Ikkonen E., Aaltonen H., Nykänen H., Martikainen P.J. 1997.
Reconstruction of the carbon balance for microsites in a boreal oligotrophic pine fen, Finland. Oecologia
110: 423-431.

482
483
484
485

Augustin, J., Merbach, W., Käding, H., Schmidt, W. & Schalitz, G. 1996. Lachgas- und Methanemission aus
degradierten Niedermoorstandorten Nordostdeutschlands unter dem Einfluß unterschiedlicher
Bewirtschaftung. In: Alfred-Wegener-Stiftun (ed.) Von den Ressourcen zum Recycling. Berlin, Ernst &Sohn. pp 131-139.

486
487
488

Augustin, J. & Merbach, W. 1998. Greenhouse gas emissions from fen mires in Northern Germany:
quantification and regulation. In: Merbach, W. & Wittenmayer, L. Beiträge aus der Hallenser
Pflanzenernährungsforschung, pp. 97-110

489
490

Augustin, J. 2003. Gaseous emissions from constructed wetlands and (re)flooded meadows. Publicationes
Instituti Geographici Universitatis Tartuensis 94: 3-8

491
492
493
494
495

Augustin, J. & B. Chojnicki, 2008. Austausch von klimarelevanten Spurengasen, Klimawirkung undKohlenstoffdynamik in den ersten Jahren nach der Wiedervernässung von degradiertem
Niedermoorgrünland. In Gelbrecht, J., D. Zak & J. Augustin (eds) Phosphor- und Kohlenstoff-Dynamik undVegetationsentwicklung in wiedervernässten Mooren des Peenetals in Mecklenburg-Vorpommern – Status,
Steuergrößen und Handlungsmöglichkeiten. Berichte des IGB Heft 26. IGB, Berlin: 50–67.

496
497
498

Augustin, unpubl., cited in Couwenberg, J., Thiele, A., Tanneberger, F., Augustin, J., Bärisch, S., Dubovik, D.,
Liashchynskaya, N., Michaelis, D., Minke, M., Skuratovich, A. & Joosten, H. (2011) Assessing greenhousegas emissions from peatlands using vegetation as a proxy. Hydrobiologia, 674, 67–89.

499
500
501

Billett M. F., Palmer M., Hope D., Deacon C., Storeton-West R., Hargreaves K. J., Flechard C. & Fowler D.
2004. Linking land-atmosphere-stream carbon fluxes in a lowland peatland system. Global Biogeochemical
Cycles 18(GB1024): doi:10.1029/2003GB002058.

502
503

Billett M. F. & Moore T. R. 2008. Supersaturation and evasion of CO2 and CH4 in surface waters at Mer Bleue
peatland, Canada. Hydrological Processes 22: 2044-2054.

504
505
506

Billett M. F., Charman C., Clark I., EVans C. D., EVans M. G., Ostle N., Worrall F., Burden A., Dinsmore K. J.,
Jones T., McNamara N. P., Parry L., Rowson J. G. & Rose R. 2010. Carbon balance of UK peatlands: current
state of knowledge and future research challenges. Climate Research 45: 13-20.

507
508

Bortoluzzi, E., Epron, D., Siegenthaler, A., Gilbert, A. & Butler, A. 2006. Carbon balance of a European
mountain bog at contrasting stages of regeneration. New Phytologist 172: 708-718

509
510

Bubier J.L., Moore T.R., Roulet N.T. 1993. Methane emissions from wetlands in the midboreal region of
Northern Ontario, Canada. Ecology 74(8): 2240-2254.

511
512

Cleary J, Roulet NT, Moore TR. 2005. Greenhouse gas emissions from Canadian peat extraction, 1990-2000: A
life-cycle analysis, Ambio, 34, 456-461.

513
514
515

Clymo R.S., Reddaway E.J.F. 1971. Productivity of Sphagnum (Bog-moss) and peat accumulation.
Hidrobiologia 12: 181-192. (cited in: Bartlett K.B. & Harris R.C. 1993. Review and assessment of Methane
Emissions from Wetlands. Chemosphere. Vol.26, Nos. 1-4: 261-320.)

516
517
518

Couwenberg, J., Thiele, A., Tanneberger, F., Augustin, J., Bärisch, S., Dubovik, D., Liashchynskaya, N.,
Michaelis, D., Minke, M., Skuratovich, A. & Joosten, H. (2011) Assessing greenhouse gas emissions frompeatlands using vegetation as a proxy. Hydrobiologia, 674, 67–89.

519
520

Crill, unpublished data. (cited in: Bartlett K.B. & Harris R.C. 1993. Review and assessment of Methane
Emissions from Wetlands. Chemosphere. Vol.26, Nos. 1-4: 261-320.)

521
522

Dinsmore K. J., Billet M. F., Skiba U. M., Rees R. M., Drewer J. & Helfter C. 2010. Role of the aquatic pathway
in the carbon and greenhouse gas budgets of a peatland catchment. Global Change Biology 16: 2750-2762.

523
524

Dise N.B., Gorham E. 1993. Environmental Factors Conrolling Methane Emissions from Peatlands in orthern
Minnesota. Journal of Geophysical Research 98 Nr. D6: 10583-10594.

525
526
527
528

Drewer J., Lohila A., Aurela M., Laurila T., Minkkinen K., Penttilä T., Dinsmore K. J., McKenzie R. M., HelfterC., Flechard C., Sutton M. A. & Skiba U. M. 2010. Comparison of greenhouse gas fluxes and nitrogenbudgets from an ombotrophic bog in Scotland and a minerotrophic sedge fen in Finland. European Journal of
Soil Science: 10.1111/j.1365-2389.2010.01267.x

DRAFT 2013 Wetlands Supplement

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Chapter 3: Cross-cutting guidance on rewetted peatlands and organic soils

DO NOT CITE OR QUOTEFirst-order Draft
529
530

Drösler, M. 2005. Trace gas exchange and climatic relevance of bog ecosystems, southern Germany. PhD thesis,
Technische Universität München. 182p.

531
532

Flessa, H., Wild, U., Klemisch, M. & Pfadenhauer, J. 1997. C- und N-Stoffflüsse auf
Torfstichsimulationsflächen im Donaumoos. Zeitschrift für Kulturtechnik und Landentwicklung 38:11-17.

533
534

Gauci V., Dise N. 2002. Controls on supression o methane flux from a peat bog subjected to simulated acid rain
sulfate deposition. Global Biogeochemical Cycles 16 Nr. 1: 4-1 to 4-12.

535
536

Glatzel, S., Koebsch, F., Beetz, S., Hahn, J., Richter, P., Jurasinski, G., 2011. Maßnahmen zur Minderung derTreibhausgasfreisetzung aus Mooren im Mittleren Mecklenburg. Telma. 4: 85-106.

537
538
539

Harriss R.C., Sebacher D.I., Day F.P. 1982. Methane flux in the Great Dismal Swamp. Nature 297: 673-674.
(cited in: Bartlett K.B. & Harris R.C. 1993. Review and assessment of Methane Emissions from Wetlands.
Chemosphere. Vol.26, Nos. 1-4: 261-320.)

540
541

Hendriks, D.M.D., van Huissteden, J., Dolma, A.J. & van der Molen, M.K. 2007. The full greenhouse gasbalance of an abandoned peat meadow. Biogeosciences 4: 411-424

542
543
544

Jungkunst, H.F. & Fiedler, S. 2007. Latitudinal differentiated water table control of carbon dioxide, methane andnitrous oxide fluxes from hydromorphic soils: feedbacks to climate change. Global Change Biology 13:
2668-2683

545
546
547

Juottonen, H., Hynninen, A., Nieminen, M., Tuomivirta, T., Tuittila, E-S., Nousiainen, H., Yrjälä, K.,
Tervahauta A., Fritze, H. Methane-cycling microbial communities and methane emission in natural andrestored peatland buffer areas. Submitted to Applied and Environmental Microbiology in January 2012.

548
549

Koehler A-K, Sottocornola M, Kiely G, 2011. How strong is the current carbon sequestration of an Atlantic
blanket bog? Global Change Biology, 17, 309–319.

550
551
552

Komulainen, V.-M., H. Nykanen, P. J. Martikainen, Laine, J. 1998. Short-term effect of restoration on vegetation
change and methane emissions from peatlands drained for forestry in southern Finland. Canadian Journal ofForest Research 28: 402-411.

553
554
555

Laine J., Silvola J., Tolonen K., Alm J., Nykänen H., Vasander H., Sallantaus T., Savolainen I., Sinisalo J.,
Martikainen P.J. 1996. Effect of Water-level Drawdown on Global Climatic Warming: Northern Peatlands.
Ambio Vol. 25 No. 3: 179-184. Royal Swedish Academy of Sciences.

556
557

Nagata, O., Takakai, F. & Hatano, R. 2005. Effect of Sasa invasion on global warming potential in Sphagnum
dominated poor fen in Bibai, Phyton, 45:299-307.

558
559

Nagata, O., Yazaki, T., Yanai, Y. 2010. Nitrous oxide emissions from drained and mineral soil-dressed peatland
in central Hokkaido, Japan. Journal of Agricultural Meteorology, 66:23-30

560
561
562

Nilsson M, Sagerfors J, Buffam I, Laudon H, Eriksson T, Grelle A, Klemedtsson L, Weslien P, Lindroth A,
2008. Contemporary carbon accumulation in a boreal oligotrophic minerogenic mire – a significant sink after
accounting for all C-fluxes Global Change Biology 14, 2317–2332.

563
564

Nykänen H., Alm J., Lang K., Silvola J., Martikainen P. 1995. Emissions of CH4, N2O and CO2 from a virgin
fen and a fen drained for grassland in Finland. Journal of Biogeography 22: 351-357.

565
566
567

Saarnio S, Morero M, Shurpali NJ, Tuittila E-S, Mäkilä M, Alm J (2007) Annual CO2 and CH4 fluxes ofpristine boreal mires as a background for the lifecycle analyses of peat energy, Boreal Environment Research
12: 101-113.

568
569

Scottish Executive. 2007. Ecosse - Estimating Carbon in Organic Soils, Sequestration and emissions. Scottosh
Executive, Edinburgh. http://www.scotland.gov.uk/Publications/2007/03/16170508 [febr. 2008]. 177 p.

570
571

Shannon R.D., White J.R. 1994. A three-year study of controls on methane emissions from two Michigan
peatlands. Biogeochemistry 27: 35-60.

572
573
574

Sommer, M., Fiedler, S., Glatzel, S. & Kleber, Markus. 2003. First estimates of regional (Allgäu, Germany) andglobal CH4 fluxes from wet colluvial margins of closed depressions in glacial drift areas. Agriculture
Ecosystems & Environment 103: 251-257

575
576

Strack M., Toth K., Bourbonniere R. A. & Waddington J. A. 2011. Dissolved organic carbon production andrunoff quality following peatland extraction and restoration. Ecological Engineering 37: 1998-2008.

577
578

Tauchnitz, N., Brumme, R., Bernsdorf, S. & Meissner, R. 2008. Nitrous oxide and methane fluxes of a pristine
slope mire in the German National Park Harz Mountains. Plant and Soil 303, 131-138

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579
580

Tuittila E.-S., Komulainen V.-M., Vasander H., Nykänen H., Martikainen P.J., Laine J. 2000. Methane dynamics
of a restored cut-away peatland. Global Change Biology 6: 569-581.

581
582
583

Urbanová, Z., Picek, T., Hájek, T., Bufková, I., Tuittila, E-S. Impact of drainage and restoration on vegetationand carbon gas dynamics in Central European peatlands. Conditionally accepted to Plant Ecology andDiversity, 2012.

584
585
586
587

Verma S.B., Ullman F.G., Billesbach D., Clement R.J., Kim J., Verry E.S. 1992. Eddy correlation measurementsof methane flux in a northern peatland ecosystem. Bound. Layer Meteorol. 58:289-304. (cited in: Bartlett
K.B. & Harris R.C. 1993. Review and assessment of Methane Emissions from Wetlands. Chemosphere.
Vol.26, Nos. 1-4: 261-320.)

588
589

Von Arnold, K. 2004. Forests and greenhouse gases - fluxes of CO2, CH4 and N2O from drained forests onorganic soils. Linköping Studies in Arts and Science no 302. 48p.

590
591

Waddington J.M., Price J.S. 2000. Effect of peatland drainage, harvesting, and restoration on atmospheric waterand carbon exchange. Physical Geography 21, 5: 433-451.

592
593

Waddington J.M., Roulet N.T. 2000. Carbon balance of a boreal patterned peatland. Global Change Biology 6:
87-97.

594
595

Whiting G.J. & Chanton J.P. 2001. Greenhouse carbon balance of wetlands: methane emission versus carbon
sequestration. Tellus 53B: 521-528.

596
597

Wickland K.P., Striegl R.G., Mast M.A., Clow D.W. 2001. Carbon gas exchange at a southern Rocky Mountainwetland 1996-1998. Global Biogeochemical Cycles 15 Nr. 2: 321-335.

598
599

Wild, U., Kamp, T., Lenz, A., Heinz, S. & Pfadenhauer, J. 2001. Cultivation of Typha spp. in constructedwetlands for peatland restoration. Ecological Engineering 17:49-54

600
601
602

Wilson D., Alm J., Laine J., Byrne K. A., Farrell E. P. & Tuittila E.-S. 2009. Rewetting of cutaway peatlands:
Are we re-creating hotpots of methane emissions? Restoration Ecology 17(6): 796-806 doi: 10.1111/j.1526100x.2008.00416.x.

603
604
605

Wilson D., Renou-Wilson F., Farrell C., Bullock C. & Müller C. In press. Carbon Restore - The potential ofpeatlands for carbon sequestration. Climate Change Research Programme Report. Environmental Protection
Agency. Johnstown Castle, Co. Wexford, Ireland.

606
607
608
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Wilson J.O., Crill P.M., Bartlett K.B., Sebacher D.I., Harriss R.C., Sass R.L. 1989. Seasonal variation of
methane emissions from a temperate swamp. Biogeochem. 8: 55-71. (cited in: Bartlett K.B. & Harris R.C.
1993. Review and assessment of Methane Emissions from Wetlands. Chemosphere. Vol.26, Nos. 1-4: 261320.)

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Worrall F., Burt T. P., Rowson J. G., Warburton J. & Adamson J. K. 2009. The multi-annual carbon budget of apeat-covered catchment. Science of the Total Environment 407: 4084-4094

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Yli-Petäys, M., Laine, J., Vasander, H. & Tuittila, E.-S. 2007: Carbon gas exchange of a re-vegetated cut-away
peatland five decades after abandonment. Boreal Environmental Research 12: 177–190.

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Estimation of default emission factors for CO2-C inrewetted peatlands and organic soils

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An extensive literature review was conducted to collate all greenhouse gas (GHG) studies that are currently
available for natural/undrained and rewetted peatlands and organic soils. Literature sources included bothpublished and non-published (grey literature) studies. In the case of the latter, expert judgement was exercised as
to whether the study was scientifically acceptable for inclusion. A greater amount of data from natural(undrained) is available than from re-wetted peatlands. A detailed database of annual CO2 fluxes was thenconstructed to determine the main drivers (if any) of CO2 dynamics in rewetted peatlands and organic soils.
When available, the following parameters were extracted and included in the database for analysis: climate zone
(latitude), peatland types, mean annual water table, median annual water table (as well as minimum andmaximum), soil pH, peat thickness, peat C/N ratio, degree of humification, soil moisture, soil bulk density, plant
cover and species, previous land-use and time since re-wetting.

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To determine Tier 1 CO2 emission factors, descriptive statistics allowed the data to be grouped by (1) climate
region, (2) peatland type (bog or fen) and (3) climate region and peatland type, and descriptive analysis for eachgroup was computed. Due to difficulties in up-scaling flux data or incomplete data entries a proportion of theCO2 flux entries in the database (12-33%) were not used in the analysis. Studies that reported daily CO2 flux
values in the database were not used. Seasonal CO2 fluxes (typically May to October) were converted to annual
fluxes by assuming that 15% of the flux occurs in the non-growing season (Saarnio et al. 2007). Tropicalpeatlands were initially included in the database and although several studies were first extracted, the number ofusable entries was deemed very limited (one re-wetted and three undrained/natural entries) and were therefore
excluded thereafter.

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While all re-wetted entries were included (n=62), data from natural/undrained were further extracted and only
entries (n=82) from sites with a mean annual water table of no less than 30 cm was used as a proxy for re-wetted
sites. These entries were well distributed between bogs (n=79) and fens (n= 65). There were 63 boreal entries
compared with 81 temperate entries with temperate bogs being the most common studied type.

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While a total 142 fluxes were entered for the analysis (Figure 3A.1), 130 entries were used in the final databaseto calculate the emission factors.

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Firstly, a comparison was made between re-wetted sites and natural/undrained sites. The range of fluxes fromboth groups is analogous (Figure 3A.1).

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Figure 3A.1

Annex 3A.1

CO2 flux (g m-2 yr-1)

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Re-wetted
Undrained

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The fitted regression lines (CO2 flux = a+b1*WT) were compared between re-wetted and natural/undrainedgroups for each category. The two groups were treated as being non-significantly different when it was
ascertained statistically that b1 +-S.E. (rewetted) fitted within b1-S.E. and b1+S.E for the natural/undrainedgroup. This was the case for all but the temperate fen groups. Therefore, emission factors were calculated using
re-wetted and natural/undrained entries for all categories except for temperate fens where only re-wetted entries(n=17) were used in the calculation of the emission factor. Total number of entries used overall was 130.

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Collated data from seven peat re-wetting studies suggest a median DOC reduction of 36%, with a range of 169%. While the number of studies is limited, and results are fairly variable, the median reduction is almost
exactly equivalent to the observed increase following drainage (a 33% decrease would be required to fully
reverse a 50% increase). A study by Glatzel et al. (2003) observed similar DOC concentrations in re-wetted andrestored bogs (previously used for peat harvesting) as in a nearby intact reference bog. Therefore, there is someevidence to suggest that peat re-wetting will return DOC loss fluxes to natural levels. This is likely to occur after
an initial pulse of DOC associated with disturbance during the re-wetting process (e.g. Zak and Gilbrecht, 2007;
Worrall et al., 2007, Strack et al., 2011), which may contribute to the variability shown in Table 3A.X, wheresome measurements were made soon after re-wetting.

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The values derived for the estimation of DOCFLUX_NATURAL are explained in Annex X of Chapter 2 as well as an
explanation of the estimated FDOC-CO2

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TABLE 3A.1
DOC CONCENTRATION (ABOVE) OR FLUX (BELOW) COMPARISONS BETWEEN DRAINED AND RE-WETTED PEATSDOC (mg/l)

DOCRE-WET

Previous land-use

Country

Study

DrainedRe-wetted(%)

Peat extraction bog

CanadaGlatzel et al (2003)

110

70

-36%

Drained blanket bog

UK

Wallage et al (2006)

43

13

-69%

Drained blanket bog

UK

Armstrong et al (2010)

34

30

-10%

Drained blanket bog

UK

Gibson et al (2009)

39

39

-1%

Drained agricultural fen

Germany

Höll et al (2009)

86

57

-34%

r-1

Previous land-use

Country

Study-2

DOC (g C m y )Undrained

Drained

DOCRE-WET(%)

Peat extraction bog

CanadaWaddington et al (2008)

7.5

3.5

-53%

Drained blanket bog

UK

O’Brien et al (2008)

7.0

4.1

-41%

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Estimation of default emission factors for CH4-C inrewetted peatlands and organic soils

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The same literature database and general approach were used to develop default CH4 emission factors as was
described in Annex 3.1. Similarly, a greater amount of data from natural (undrained) peatlands is available thanfrom re-wetted peatlands. A detailed database of annual CH4 fluxes was then constructed to determine the main
drivers (if any) of CH4 emissions in rewetted peatlands and organic soils. Where possible, the analysis
considered the same parameters : climate zone (latitude), peatland types, mean annual water table, medianannual water table (as well as minimum and maximum), soil pH, peat thickness, peat C/N ratio, degree of
humification, soil moisture, soil bulk density, plant cover and species, previous land-use and time since rewetting.

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Methane fluxes from rewetted boreal peatlands (mean 80.3 kg CH4-C ha-1 yr-1; variance; n=27 2 ) aresignificantly lower than from undrained (pristine) sites (mean 205.4 kg CH4-C ha-1 yr-1; variance; n=873). The
increase in efflux with rising water level is similar, but significantly steeper for undrained sites (n=68 pairs)
compared to rewetted sites (n= 13 pairs). Methane efflux from rewetted fens (mean 161.6 kg CH4-C ha-1 yr-1;
variance; n=12) is an order of magnitude higher than efflux from rewetted bogs (mean 16.2 kg CH4-C ha-1 yr-1;
variance; n=12), which is mirrored by efflux values from undrained fens (mean 392.5 kg CH4-C ha-1 yr-1;
variance; n=33) and bogs (65.6 kg CH4-C ha-1 yr-1; variance; n=42).

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Whereas methane fluxes from rewetted temperate peatlands (mean 416.1 kg CH4-C ha-1 yr-1; variance; n=474)
are considerably higher than from undrained peatlands (mean 148.7 kg CH4-C ha-1 yr-1; variance; n=615), thisfinding is based mainly on a small number of extremely high efflux values from sites on enriched agriculturalsoil that were flooded during rewetting (Augustin & Chojnicki 2008; Glatzel et al., 2011). The increase in efflux
with rising water level is not significantly different between undrained (n=39 pairs) and rewetted sites (n=40pairs), nor between undrained bogs (n=35) and undrained fens (n=22). Flux values from rewetted sites do show
higher variance, however, which cannot be explained by available parameters (peat type, water level dynamics,
pH, C/N ratio, vegetation), although the highest values were measured in recently rewetted fen peatlands,
formerly used as high-intensity grassland (time since rewetting ≤ 2 years). Methane effluxes from rewetted
temperate bogs are an order of magnitude lower than from fens, but measurements are restricted to only threebog sites. Combined, the increase in efflux with rising water level in undrained and rewetted sites does not show
a significant difference between bogs (n=30 pairs) and fens (n=49 pairs). The emission factors presented are
based on the total dataset of rewetted and undrained bogs (n=41) and fens (n=63). Because bogs have more
relatively dry microsites and the dataset for fens includes the extreme values mentioned above, the EF for
temperate bogs is lower than for fens.

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Very few methane flux data exist on rewetted tropical peatlands. Comparison of hourly flux data suggests that
efflux in SE Asian peat swamps (the largest extent of tropical peatland) will be much lower than intemperate/boreal regions (Couwenberg et al., 2010). Efflux from rice padi on peat soil is comparable to current
IPCC estimates (Couwenberg 2011). Efflux from Papyrus marshes has been measured, paper is underway…

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Juottonen et al., 2012; Komulainen et al., 1998; Tuittila et al., 2000 ; Urbanová et al., 2012 ; Yli-Petäys et al., 2007

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Alm et al., 1997; Bubier et al., 1993; Clymo & Reddaway, 1971; Drewer et al., 2010; Gauci & Dise 2002; Laine et al.,1996 ; Nykänen et al., 1995 ; Verma et al., 1992 ; Waddington & Roulet 2000 ; Whiting & Chanton 2001

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Augustin & Chojnicki 2008; Augustin & Merbach 1998; Augustin 2003; Augustin in Couwenberg et al. 2011; Cleary et al.,2005; Drösler 2005; Flessa et al., 1997; Glatzel et al., 2011; Hendriks et al., 2007; Jungkunst & Fiedler 2007; Waddington& Price 2000; Wild et al., 2001; Wilson et al., 2009; Wilson et al., in press

5

Augustin & Merbach 1998; Augustin 2003; Augustin et al., 1996; Augustin in Couwenberg et al. 2011; Bortoluzzi et al.
2006; Crill in Bartlett & Harris 1993; Dise & Gorham 1993; Drösler 2005; Harriss et al., 1982; Koehler et al., 2010;
Nagata et al., 2005; Nilsson et al., 2008; Roulet et al., 2007; Scottish Executive, 2007; Shannon & White 1994; Sommer etal., 2003; Tauchnitz et al., 2008; Von Arnold 2004; Waddington & Price 2000; Wickland et al., 2001; Wilson et al., 1989

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APPENDIX 3.1
CO 2 Emissions/Removals from Re-Wetted
Peatlands or Organic Soils in Tropical Climates: a Basis for
Future Methodological Development

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APPENDIX 3.1
Time-Series of EFDOC Rewetted; a Basis For
Future Methodological Development

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