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HYDROLOGICAL PROCESSESHydrol[ Process[ 03\ 0468Ð0478 "1999#

Copyright © 2000 John Wiley & Sons, Ltd.Received 11 May 1999

Accepted 17 September 1999

Advances in Canadian wetland hydrology andbiogeochemistry

J[ S[ Price0� and J[ M[ Waddington1

0 Department of Geo`raphy\ University of Waterloo\ Waterloo\ Ontario N1L 2G0\ Canada1 School of Geo`raphy and Geolo`y\ McMaster University\ Hamilton\ Ontario L7S 3K0\ Canada

Abstract]Wetlands comprise 03) of the land area of Canada[ They have considerable impact on water storage and

runo}\ water quality\ atmospheric exchanges of carbon\ and important elements such as nitrogen[ In less remote

parts of Canada\ wetlands have su}ered from reclamation\ exploitation\ contamination and degradation\ which

have seriously impaired their ecological function[ Public recognition of their environmental signi_cance has

highlighted the need for a better understanding of the hydrological processes\ to better plan and manage

wetland areas\ restore degraded systems\ and predict responses to global change[ This paper reviews current

hydrological research in all types of Canadian wetlands[ The scope of hydrological processes discussed herein

includes runo}\ surface and groundwater ~ows\ evaporation\ microclimate\ water balance\ geochemical and

solute transport phenomenon\ carbon dynamics\ isotope studies\ exploitation and restoration[ Field\ laboratory

and modelling studies are included[ Copyright Þ 1999 John Wiley + Sons\ Ltd[

KEY WORDS Canadian wetlands^ hydrology^ biogeochemistry^ peatlands\ review solute transport^ humanimpacts^ carbon cycling

PREAMBLE

This paper provides an overview of recent advances in wetland hydrology in Canada[ To facilitate this\background information is provided to de_ne the setting and fundamental hydrological processes[ Wherenecessary\ we have drawn upon other literature on wetlands both within and outside of Canada\ to providethe context for more recent initiatives[ It is important to note that research e}ort has not focused evenly onthe various wetland classes de_ned below\ most of it reporting on peatland systems\ which represent over89) of Canadian wetlands "Tarnocai\ 0887#[ This review necessarily re~ects that bias[

BACKGROUND

Wetlands are areas with the water table at\ near or above the land surface for long enough to promotehydric soils\ hydrophytic vegetation and biological activities adapted to wet environments "Tarnocai\ 0879#[In Canada these may be classi_ed a bog\ fen\ swamp\ marsh or shallow water "National Wetlands WorkingGroup\ 0886#[ This categorization recognizes that hydrological processes resulting from water exchangesdictated by climate and landscape factors\ largely determine wetland form "National Wetland WorkingGroup\ 0886#[ Wetlands may be mineralÐsoil wetlands or peatlands[ Mineral wetlands include marsh\shallow water and some swamps\ and produce little or no peat\ because of climatic or edaphic conditions"Zoltai and Vitt\ 0884#[ Peatlands are wetland areas with an accumulation of peat exceeding 39 cm\ and

Correspondence to] J[ S[ Price\ Department of Geography\ University of Waterloo\ Waterloo\ Ontario N1L 2G0\ Canada[ E!mail]jspriceÝwatserv0[uwaterloo[ca

J[ S[ PRICE AND J[ M[ WADDINGTON

Copyright Þ 1999 John Wiley + Sons\ Ltd[ Hydrol[ Process[ 03\ 0468Ð0478 "1999#

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include bogs\ fens and some swamps[ Fens and swamps are mineratrophic\ receiving water and nutrientsfrom atmospheric and telluric sources\ whereas bogs are ombrotrophic\ receiving water and nutrients onlyfrom direct precipitation "National Wetland Working Group\ 0886#[

WETLAND DISTRIBUTION AND DEVELOPMENT

The Ecological Strati_cation Working Group "0887# has recently characterized the general climate\ soil andvegetation of the Canadian wetland regions\ and noted the various wetland forms therein[ The regionaldistribution of bogs\ fens\ swamps\ marshes and shallow water wetlands in Canada "National WetlandsWorking Group\ 0875# is related to latitudinal and meridianal gradients[ Latitudinal e}ects control peataccumulation and other aquatic processes through di}erences in "i# productivity rates as in~uenced byradiation and temperature "Frolking et al[\ 0887#\ and "ii# decomposition rates as in~uenced by moistureavailability and temperature "Clymo\ 0886#[ Moisture availability is a function of atmospheric water supplyand energy available for evapotranspiration[ Meridianal e}ects are related to the degree of continentality\hence moisture restrictions that are associated with temperature and precipitation gradients "Halsey et al[\0886a#[ Damman "0868# noted that in eastern North America there is a northern and southern limit to bogoccurrence\ as they are reliant on ombrogenous water[ Similar climatic and physiographic e}ects were notedin Manitoba wetlands "Halsey et al[\ 0886b#[ Precipitation and evapotranspiration decrease northwards andlimit water supply[ Therefore\ only limited occurrence of bogs is noted in more continental and Arcticlocations[ Wetlands with surface water or groundwater in~ows are more common outside the range mostsuited to bogs[ In fact\ most wetland forms are derived from minerogenous settings\ where water interactswith mineral soils[ Plant succession in these settings is strongly related to hydrological conditions and theassociated ~ow of nutrients and mineral elements "Klinger and Short\ 0885#[ This may result in the accumu!lation of peat\ which can alter recharge:discharge functions\ such as occurs in the Hudson Bay lowlandwhere marsh and fen give way to bog after a long period of succession "N[ T[ Roulet\ unpublished data#[Sometimes these processes are related to other physical changes that cause water table rises\ such as theaggradation of permafrost "Vardy et al[\ 0887#\ or land clearance and climatic change "Campbell et al[\0886#[ Thermal and hydrological feedback in the Arctic perpetuates patchy wetlands\ and frost heave orstream capture can cause degradation "Woo and Young\ 0887#[ Other edaphic controls such as iron!panformation "Lapen et al[\ 0885# or simply peat development "Emili et al[\ 0887#\ can cause changes in drainageand wetland evolution[ The percentage cover of the ground surface that is peatland\ however\ dependsstrongly on local topographic and hydraulic constraints[ For example "Graniero and Price\ 0888a# showedthat topography can explain the occurrence of 11) of the blanket bogs in a Newfoundland landscape[Nevertheless\ this could be used to model bog occurrence with ×69) accuracy "Graniero and Price\ 0888b#\because to a large extent topographic structure controls peat diagenesis[ New techniques using testateamoebae "Charman and Warner\ 0886# enable reconstruction of past water table regimes associated withwetland evolution[

ATMOSPHERIC PROCESSES

SoilÐvegetationÐatmosphere exchanges of moisture and energy essentially drive the hydrological systemand all other hydrological processes[ The type and distribution of wetland vegetation a}ect patterns ofrain\ snow and fog precipitation[ Forested wetlands\ in particular\ are susceptible to complex patterns ofprecipitation input resulting from the disturbance of air~ow by wetland tree species\ radiative snowmeltcharacteristics "La~eur et al[\ 0886^ Hamlin et al[\ 0887#\ and interception "Dube� et al[\ 0884#[ Interceptionby trees in a Quebec swamp was 24 to 30) of rainfall "Dube� et al[\ 0884#[ Similarly\ Van Seters "0888#recorded seasonal interception of 21) in a spruce bog\ and 01) by timber harvest debris[ Dissolved organiccarbon "DOC# in throughfall and stem~ow comprised up to 19) of total export "Hinton et al[\ 0887#[ The

WETLAND HYDROLOGY AND BIOGEOCHEMISTRY


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geochemical signature of intercepted water can be markedly di}erent from rainfall "Cox et al[\ 0885#\ andmay signi_cantly a}ect wetland chemistry[

Evaporation from non!vascular Spha`num mosses was shown to be well below potential evaporation"Campbell and Williamson\ 0886#\ compared with relatively e.cient latent heat transfer by "vascular# sedges"La~eur et al[\ 0886#[ Price "0885# noted that daily net radiation and evaporation ~ux from a Spha`num!dominated surface were similar to a bare peat surface * the latter having an e}ective capillary water supply[Evaporation from shallow Arctic lakes was 04Ð69) greater than values predicted from standard evaporationmaps of Canada "Gibson et al[\ 0885#[ Models of evapotranspiration continue to be an important approach[The PriestlyÐTaylor "0861# combination model of evaporation was used successfully in a variety of settings\including shallow water "Gibson et al[\ 0885#\ fen "Rouse\ 0887# and bog "Price\ 0885#[ Soil water balancemodels driven by precipitation and wetland evaporation were used to simulate water table response in borealpeatlands "Metcalfe and Buttle\ 0888^ Cuenca et al[\ 0886#\ subarctic fens "Boudreau and Rouse\ 0884^Rouse\ 0887# and prairie sloughs[ There have been recent e}orts to try and improve the representation ofwetlands in global climate modelling[ Letts et al[ "in press# have proposed a new set of soil parameters forpeat to be included in the Canadian Land Surface Scheme "CLASS# model "Verseghey et al[\ 0882#\ whichhave resulted in improved estimates of water table and soil temperature in wetlands[ Estimates of turbulent~uxes from CLASS\ incorporating the new soil climate parameters\ indicate good results for fen and marshwetlands\ but non!vascular bog!type wetlands remain relatively poorly modelled "Comer et al[\ in press#[

SURFACE AND GROUNDWATER FLOW AND RUNOFF

Field studies of surface ~ows have provided new insight into water pathways within\ and runo} fromwetlands[ The pathways include vertical and horizontal movement within the various layers\ and sheet~owand channel ~ow over the surface "Taylor\ 0886#\ as well as water exchanges with upland systems "Bran_reunand Roulet\ 0887^ Hayashi et al[\ 0887a#[ Devito et al[ "0885# found that during seasons with large waterinputs\ swamps were hydrologically connected to uplands\ and that overland ~ow dominated in the wetland[Quinton and Roulet "0887# and Glenn and Woo "0886# noted that peatlands operate as a single source areawith rapid response for spring runo} when the water table exceeded the depression storage capacity ofpatterned wetland pools[ Relatively slow responses occurred when pools became {disconnected| into separatemicro!catchments during drier periods "Quinton and Roulet\ 0887#[ Similarly\ in an Arctic hillslope highwater table conditions in riparian peat o}ered little attenuation to drainage\ but at lower water tables inter!hummock drainage pathways decreased the source area and hence drainage rate "Quinton and Marsh\0887a\b#[ Comparable results were noted by Devito et al[ "0885# who found little runo} attenuation from aheadwater conifer swamp on the southern Canadian Shield[ Other studies also indicated the importance ofassessing storage capacity in wetlands\ for example with permafrost "Boudreau and Rouse\ 0884^ Woo andXia\ 0885^ Glenn and Woo\ 0886^ Woo and Young\ 0887# and with beaver pools "Butler and Malanson\0883^ Hillman\ 0887#[ Metcalfe and Buttle "0888# found that soil moisture de_cits during dry years in thewetland regions of a forested boreal watershed had a signi_cant impact on the magnitude of the subsequentspring runo} peak[

Modelling studies of surface and subsurface ~ows in swamps incorporating hummock terrain and organiclayers have demonstrated the complexity and variability in the hydrological response to even a singleprecipitation input "McKillop et al[\ 0888a#[ Relatively simple models based on storage and transportrelationships in a series of reservoirs have been used to track stormwater in unregulated swamps "McKillopet al[\ in press#\ and wetland responses around an urban stormwater framework "McKillop et al[\ 0888b#[Such models were sensitive to precipitation input and antecedent saturation "McKillop et al[\ 0888c# asnoted in _eld studies above[

Groundwater transport theory does not always readily suit wetland hydrological conditions becauseof high cation exchange capacity of organic sediments\ intensive biological activity\ and soil structuralcharacteristics "Price and Schlotzhauer\ 0888#[ Moreover\ strong surfaceÐgroundwater interactions "Bran!



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_reun and Roulet\ 0887# are di.cult to model[ Nevertheless\ groundwater movement in near!surface peatlayers can be most important when water inputs are from shallow soil layers "Devito et al[\ 0885#[ Evaporativewater loss and water table drawdown caused groundwater ~ow reversals in peatlands in Ontario and Sweden"Devito et al[\ 0886#\ and in a drained peatland in Quebec "Van Seters\ 0888#[ Deeper groundwater in~owswere important in some fens and swamps "Devito\ 0884#[ A Prairie slough was observed to have a deepseepage component comprising as much as 64) of the annual outputs\ much of this in_ltrating radiallyoutward beneath the upland "Hayashi\ et al[\ 0887a#\ where evapotranspiration drives water and salt upwards"Hayashi et al[\ 0887b#[ Indeed\ land!use in adjacent areas plays a critical role in the water balance of Prairiesloughs "Van der Kamp et al[\ 0888#[ In a study of a Lake Erie lakeshore marsh\ precipitation and surfacein~ow were the main water inputs\ except in the barrier bars where precipitation and lake water intermix"Huddart et al[\ 0888#[ They found also that the width of the barrier bar\ and its consequences on thehydraulic gradient\ were important in regulating water and nitrate exchanges[

Relatively few micro! or meso!scale studies of surface and groundwater ~ow were reported[ At the meso!scale\ drainage through soil pipes was noted to be important in several Arctic wetlands "Quinton and Marsh\0887c^ Carey and Woo\ 0888#[ These are known to be very important in increasing hydraulic conductivityof forest soils "Buttle and House\ 0886#\ and blanket bogs in the UK "Sklash et al[\ 0885#[ At the micro!scale\ peat properties and ~ow dynamics have been shown to be sensitive to compression and expansion ofthe peat deposit\ as the water pressure changes[ Price and Schlotzhauer "0888# found the resultant speci_cstorage to be larger than speci_c yield and only when considered together could the predicted seasonalwater storage changes simulate the observed values[ Schlotzhauer and Price "0888# showed that hydraulicconductivity decreased\ and water retention increased as the peat underwent seasonal subsidence[ Theseprocesses were important to consider in parameterizing a numerical model of groundwater ~ow in peat"Schlotzhauer\ 0887#[

SOLUTE TRANSPORT AND WETLAND GEOCHEMISTRY

Under certain conditions solutes may move quickly in surface water "Prescott and Tsanis\ 0886# and in thesubstrate "Fernandes et al[\ 0885#[ However\ in peat\ retardation of a conservative solute "Cl−# was observedin a blanket bog "Hoag and Price\ 0884# and in the laboratory "Hoag and Price\ 0886#[ Hoag and Price"0886# attributes this to matrix di}usion of solute into closed pores and cellular remains of peat formingvegetation[ The ability of wetlands to attenuate contaminant ~ows has long been recognized\ and naturaland arti_cial wetlands have been used in locations as diverse as the Canadian Arctic "Doku and Heinke\0884#\ southern urban systems "Hel_eld and Diamond\ 0886#\ natural marshland "Fernandes et al[\ 0885#and abandoned mine sites "Sobolewski\ 0885#[ Wetlands were shown to have a large capacity to removecontaminants\ such as land_ll leachate\ for long periods "Fernandes et al[\ 0885#[ However\ removal is notpermanent\ because wetlands have a limited capacity and o}er only temporary storage of contaminantinputs "Hel_eld and Diamond\ 0886#[ Arti_cial wetlands are typically better at this because of superiorcontrol of water inputs and residence time "Mulamoottil et al[\ 0885#[

UplandÐwetland groundwater interactions not only provide an important hydrological function\ but alsoprovide a critical geochemical function "Hill\ 0885^ Devito and Hill\ 0886^ Hill and Devito\ 0886^ Bran_reunand Roulet\ 0887^ Bran_reun et al[\ 0887^ Hayashi et al[\ 0887b#[ Devito "0884# demonstrated that greatersulphate "SO−1

3 # retention occurred in headwater wetlands receiving groundwater rich in SO−13 [ Sites with

ephemeral groundwater inputs resulted in SO−13 exports after drought periods "Devito\ 0884^ Devito and

Hill\ 0886#[ Devito et al[ "0887# used till thickness as an indicator of uplandÐwetland groundwater connect!ivity[ They discovered high "×19 mg:l# SO−1

3 concentrations occurred only in streams in thin till "limitedgroundwater# catchments during dry summers[ Bran_reun et al[ "0885# demonstrated that micro!scalegroundwater recharge and discharge zones corresponded to sites of low and high pore water methylmercury"MeHg# concentrations\ respectively[ They also found that when the water table rose to the surface in thesedischarge {hot!spot| zones\ MeHg laden pore water moved into local streams[ Bran_reun et al[ "0887# also



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used a simple catchment!scale\ cascade model to demonstrate the importance of peatland presence oncatchment MeHg yield[ The presence of peatlands in northern watersheds has been used to explain theacidity of lakes in northeastern Alberta "Halsey et al[\ 0886a#[ Fens\ with higher ~ow and hydrologicalconnection to the surrounding watershed\ were found to be more e}ective in altering the acidity of down!stream lakes than bogs[

PEATLAND CARBON CYCLING

Peatlands represent a long!term net sink of atmospheric carbon dioxide "CO1# and a net source of atmosphericmethane "CH3# and play an important role in the global carbon cycle[ These factors are both directly andindirectly in~uenced by hydrology "Moore et al[\ 0887#\ which increases the interannual variability in carbonstorage[ For example\during wet summers anaerobic conditions in wetland soils reduce organic matterdecomposition and stimulate CH3 production "Moore et al[\ 0887^ Worthy et al[\ 0887#[ During hot drysummers when there is a drop in moisture availability\ peatlands can become a net source of atmosphericCO1 "e[g[ La~eur et al[\ 0886^ Schreader et al[\ 0887^ Joiner et al[\ 0888# as photosynthesis is decreased andrespiration loss enhanced "Schreader et al[\ 0887#[ It is important to note\ however\ that CO1 ~uxes fromopen water pools to the atmosphere may become sinks "Waddington and Roulet\ 0885# when groundwater~ow reversals can cause the pools to become disconnected from groundwater ~ow "Devito et al[\ 0886#[ Theresulting lower water table position may permit vegetation to colonize former pool areas\ leading to higherCO1 _xation[ Groundwater ~ow reversals "Devito et al[\ 0886# have also been linked to the episodic releaseof dissolved CH3 in peat pore waters "Waddington and Roulet\ 0886#[

The concentration of dissolved methane\ inorganic and organic carbon within peat pore water\ therefore\is also a function of the seasonal patterns of production and decomposition "Waddington and Roulet\ 0886#[The mass ~ux of dissolved carbon in groundwater ~ow can also be signi_cant in both the redistribution ofdissolved carbon within peatlands and in the export to surrounding landscapes "Waddington and Roulet\0886#\ especially during base~ow conditions "Schi} et al[\ 0886#[ Export of DOC during storms has beenshown to dominate the total DOC export in autumn and winter in two Precambrian Shield catchments[Moreover\ Schi} et al[ "0886# found that the relative proportions of old groundwater and young surfacewater DOC changed seasonally in response to changes in carbon cycling dynamics and hydrological ~ow!paths[ Lower DOC export and concentrations in wetlands occurred during successive storms as DOC was~ushed from riparian areas "Hinton et al[\ 0887#[ Seasonality in surface runo} from wetlands has also beenshown to alter the composition of particulate organic matter inputs to streams "Hill and Brooks\ 0885#[

HUMAN IMPACTS ON WETLANDS

Canadian wetlands are experiencing direct "e[g[ drainage# and indirect "e[g[ climate change# impacts[ Wet!lands are vulnerable to climate change because of the delicate balance between precipitation and evaporationthat controls them "Clair\ 0887#\ which could lead to shifts in wetland distribution\ extent and function"Larson\ 0884#[ Greater seasonal water de_cits will a}ect water tables and runo} "Clair and Ehrman\ 0887#[Although winter snowmelt may full recharge a wetland\ it will remain at its capacity for a shorter time undera warmer climate "Rouse\ 0887#[

A 1×CO1 climate warming scenario will likely lead to a greater summer water de_cit in northern peatlands"Rouse\ 0887#[ Because storage of carbon in peatlands is sensitive to changes in hydrology\ dramatic changesin the peatland carbon cycling are expected "Moore et al[\ 0887#[ A lower water table position will probablyresult in increased respiration "Waddington and Roulet\ 0885#\ lower CH3 ~uxes "Roulet and Moore\ 0884^Waddington et al[\ 0885# and lower DOC ~ux "Moore et al[\ 0887#[ However\ recent research suggests thatgiven the complexity of changes in the hydrology of some regions\ di}erent responses are possible[ Wad!dington et al[ "0887# predict that some peatlands may increase carbon storage under a 1×CO1 climatescenario[ A hydrological control on net ecosystem productivity suggests that present!day {wet| wetlands may



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undergo a net increase in carbon storage as net ecosystem production is enhanced in presently unvegetatedpools[ Transitions from open water to fen have been shown to coincide with early Holocene warm periods"Vardy et al[\ 0887#[ Emissions of CH3 may remain high or increase in regions where the peat surface adjuststo change in water storage "Price and Schlotzhauer\ 0888# and where water levels remain high with theformation of collapse scars from melting permafrost "Liblik et al[\ 0886#[ Hinton et al[ "0886# have notedthat because of the variability of the relationship between DOC export and stream discharge\ the e}ects ofclimate change on DOC export are unclear[

Direct impacts occur when peatlands are drained for forestry\ agriculture\ peat harvesting or land recla!mation[ Drains provide a pathway for water to exit peatlands even when the water table is low "Prevost et

al[\ 0886#\ thereby lowering the water table and CH3 emissions "Roulet and Moore\ 0884#[ Drainage alsoincreased summer base~ow\ suspended sediments\ maximum stream temperature\ speci_c conductivity\ pH\and NH¦

3 \ NO−2 \ Ca1¦\ Mg1¦ and Na¦ stream concentrations "Prevost et al[\ 0888#[ The consequences of

the increased soil aeration in an Alberta peatland "Silins and Rothwell\ 0888# was enhanced soil oxidation"Waddington and Roulet\ 0885# and subsidence associated with the loss of buoyancy of the overlyingmaterial as the water table dropped[ Although both processes decrease water storage capacity\ they alsohave the e}ect of increasing soil bulk density\ and therefore decreasing saturated and unsaturated hydraulicconductivity\ and increasing water retention "Silins and Rothwell\ 0887#[ The higher water retention capacitycaused a rise in the thickness of the zone of capillary saturation "Silins and Rothwell\ 0888#[ Closer ditchspacing may result in better drainage\ but soil moisture variability was shown to be greater within speci_eddrain spacings than between "Rothwell et al[\ 0885#[

Forest harvesting typically follows drainage[ Site disturbance during the frost!free season transfers morehumi_ed peat to the surface\ which along with soil compaction can cause a water table rise[ This had lesse}ect on the water table\ however\ than removing trees "Groot\ 0887#[ By reducing site interception\harvesting caused a water table rise of about 19 to 49 cm "Dube� et al[\ 0884#[

Peat harvesting is an important industry in Canada and Europe "Lapalainen\ 0885#[ However\ thehydrology "Price\ 0886#\ hydrochemistry "WindMulder et al[\ 0885# and ecological functions "Lavoie andRochefort\ 0885# are seriously impaired[ Consequently\ water management strategies are required to ameli!orate the hydraulic conditions[ Blocking drainage ditches can restore the water balance "Price\ 0885#\ butmining the upper layer destabilizes the water table su.ciently that water tension near the cutover surfaceexceeds the capacity of "recolonizing# Spha`num mosses to draw moisture from the soil "Price\ 0886#[Consequently\ Spha`num becomes desiccated and may die "Sagot and Rochefort\ 0885#[ Restoration\ there!fore\ may require more invasive management\ such as the use of surface microtopography and mulches"Price et al[\ 0887#\ surface repro_ling "Bugnon et al[\ 0886#\ passive seepage reservoirs "LaRose et al[\ 0886^Schlotzhauer and Price\ 0888#\ or pumped seepage reservoirs "Price\ 0887#[ The capacity of passive seepagereservoirs to ameliorate surface conditions was modelled numerically by Schlotzhauer "0887#\ who foundsurface moisture conditions were sensitive to unsaturated hydraulic conductivity[

Hydroelectricity reservoir development "~ooding# can have a large impact on wetland hydrology andgeochemical cycling[ Hydroelectric ~ooding results in an increase in peatland temperature and anaerobicconditions\ leading to an increase in CH3 production rates "McKenzie et al[\ 0887#\ MeHg production "Kellyet al[\ 0886# and emissions of greenhouse gases "Kelly et al[\ 0886#[ Pietroniero et al[ "0888# used remotesensing as a tool to monitor hydrological conditions in the PeaceÐAthabasca Delta caused by ~ow regulation[Major ~oods in the delta have not occurred since a major tributary has become regulated\ and the absenceof signi_cant ice!jamming since 0863 "Prowse et al[\ 0885#[ The use of rock weirs and arti_cially induced ice!jams is being tested as a remedial tool to ~ood the highly productive perched basin wetlands "Prowse andDemuth\ 0885#[

Although not a human impact\ beaver dam construction has similar impacts as hydroelectricity reservoirdevelopment[ Beaver dam construction "Woo and Waddington\ 0889# increases water storage "Roulet et al[\0886# and emissions of greenhouse gases "Roulet et al[\ 0886^ Bourbonniere et al[\ 0886#\ and dam failurecan result in episodic water release[ Hillman "0887# demonstrated that a ~ood wave from such an extreme



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event\ was attenuated to 5) of the estimated upstream ~ood peak as it ~owed through a downstreamwetland[

CONCLUSIONS

Relatively little work on the regional distribution and development of peatland forms in Canada has occurredrecently\ because of the di.culty of assembling reliable data at this scale\ and because of the broadassumptions that necessarily underlie such work[ Nevertheless\ there has been con_rmation that regionalrecharge and discharge patterns can dictate wetland form\ for example in the Hudson Bay Lowlands[ Otherresearch has made re_nements in de_ning the geographical limits of peatland form and related climaticvariables[ Progress has also been made in understanding topographic constraints and edaphic processes\ butbased on a much smaller spatial scale[ Overall\ there has been a tendency for more detailed studies at thelocal scale where the range of conditions and research costs are generally smaller[

Research into atmospheric processes has been dominated by gas!~ux studies\ many of these associatedwith the BOREAS experiments near Thompson\ Manitoba[ In particular carbon dynamics has become animportant issue\ more so since the Kyoto Protocol agreement[ Recent research has given us a betterunderstanding of the e}ects of seasonal climate and surface type on ~ux variability\ but we still lack su.cientunderstanding of the subsurface processes\ ranging from microscale gas production and transport\ to thee}ect of macroscale groundwater ~ow processes[

Progress has been made in identifying and describing hydrological phenomena from runo} and surface~ows to groundwater processes in a wide variety of wetland settings[ RechargeÐdischarge relationships andconnection to upland areas have been shown to be critical to understanding gas ~uxes\ nutrient ~ows andtransport of various dissolved constituents in wetlands[ More research is needed to identify their spatial andtemporal variation\ and\ for example\ their link to seasonal ~ow reversals in peatlands[ Runo} from manywetland types has been shown to be strongly a}ected by macropores\ yet few studies have examined thisabove the plot or slope scale[ At the microscale level\ ~ow and transport processes relating to matrixdi}usion\ peat volume changes and geochemical transformations have been recognized\ but are not generallyintegrated into hydrological models or interpretation of hydrological data[

Wetlands are recognized as being important in issues relating to climate change[ In addition to beingsensitive to climate in an ecological capacity\ they play an integral role in climate change through feedbackmechanisms[ Canadian peatlands represent a signi_cant portion of the global terrestrial carbon reservoir[Its stability is strongly reliant on the hydrological processes that control the carbon balance of a peatland[More direct human impacts on wetlands resulting from drainage for forestry or peat mining result in asigni_cant release of carbon[ Approaches to wetland restoration have forged collaborative study of hydrol!ogical\ biogeochemical and ecological processes[ Biological and mechanical changes to peat soil afterdisturbance discourage regeneration of peat!forming plants\ thus carbon accumulation[

Continued e}orts in the characterization of water and nutrient pathways in all types of wetlands areneeded to improve our understanding of the processes operating at all scales in natural systems[ This hasobvious important in predicting impacts on natural systems\ but it is also important for constructed wetlands\which hold promise for improving water quality[ E}orts to manage wetlands in a resource context\ eitherfor wildlife\ timber\ peat products\ or water quantity and quality will become increasingly important\especially in view of current funding restrictions[ Ecosystem management requires that we integrate responsesbeyond the soil and plot scale\ to reasonably encompass all hydrological processes of the system[ Althoughmany modelling studies have done just this for water quantity and quality\ and atmospheric responses\many barriers remain\ because of weaknesses in understanding the smaller scale processes resulting frommechanically unstable and geochemically complex soils[ This includes hydraulic\ mechanical and bioticprocesses that a}ect system parameterization[ Many of these processes are too di.cult to control for in the_eld\ so laboratory experiments provide an important base[ It is critical that we take careful steps to ensurethat laboratory results are applicable to both _eld and modelling studies[



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Bragg OM\ Hulme PD\ Ingram HAP\ Robertson RA "eds#[ Department of Biological Sciences\ University of Dundee] Dundee^ 2Ð05[

Comer NT\ La~eur PM\ Roulet NT\ Letts MG\ Skarupa M\ Verseghy D[ In press[ A test of the Canadian Land Surface Scheme"CLASS# for a variety of wetland types[ Vol[ 27[

Cox RM\ Lemieux G\ Lodin M[ 0885[ The assessment and condition of Fundy white birches in relation to ambient exposure to acidmarine[ Canadian Journal of Forest Research 15] 571Ð577[

Cuenca RH\ Stangel DE\ Kelly SF[ 0886[ Soil water balance in a boreal forest[ Journal of Geophysical Research * Atmosphere 091]18 244Ð18 254[

Damman AWH[ 0868[ Geographic patterns in peatland development in Eastern North America[ In Classi_cation of Peat and Peatlands\Kivenen E\ Heikurainen L\ Pakarinen P "eds#[ Proceedings of the International Peat Society] Hyytiala\ Finland^ 31Ð46[

Devito KJ[ 0884[ Sulfate mass balances of Precambrian Shield wetlands * the in~uence of catchment hydrogeology[ Canadian Journalof Fisheries and Aquatic Science 41] 0649Ð0659[

Devito KJ\ Hill AR[ 0886[ Sulphate dynamics in relation to groundwater * surface water interactions in headwater wetlands of thesouthern Canadian Shield[ Hydroloìcal Processes 00] 374Ð499[

Devito KJ\ Hill AR\ Roulet N[ 0885[ GroundwaterÐsurface water interactions in headwater forested wetlands of the Canadian Shield[Journal of Hydrolo`y 070] 016Ð036[

Devito KJ\ Waddington JM\ Bran_reun BA[ 0886[ Flow reversals in peatlands in~uenced by local groundwater systems[ HydroloìcalProcesses 00] 092Ð009[

Devito KJ\ Hill AR\ Dillon PJ[ 0887[ Episodic sulphate export from wetlands in acidi_ed headwater catchments] prediction at thelandscape scale[ Bioèochemistry 33] 076Ð192[

Doku IA\ Heinke GW[ 0884[ Potential for greater use of wetlands for waste treatment in Northern Canada[ Journal of Cold ReìonsEnìneerin` 8] 64Ð77[

Dube� S\ Plamondon AP\ Rothwell RL[ 0884[ Watering up after clear!cutting on forested wetlands of the St[ Lawrence lowland[ WaterResources Research 20] 0630Ð0649[

Ecological Strati_cation Working Group[ 0886[ A National Ecoloìcal Framework for Canada[ Centre for Land and Biological ResourcesResearch\ Agriculture and Agri!Food Canada^ and State of the Environment Directorate\ Environment Canada\ Ottawa[

Emili LA\ Konig CL\ Turunen J\ Price JS\ Warner BG\ Aravena R\ Bannere A[ 0887[ Hydrogeochemistry and peat development in acoastal cedarÐhemlock bogÐforest complex[ In Structure\ Processes\ and Diversity in Successional Forests of Coastal British Columbia\Trofymow JA\ MacKinnon A "eds#[ Northwest Science 16"61 SPI:1#] 59Ð51[

Fernandes L\ Warith MA\ LaForge F[ 0885[ Modelling of contaminant transport within a marshland environment[ Waste Manaèment05] 538Ð550[

Frolking SE\ Bubier JL\ Moore TR\ Ball T\ Bellisario LM\ Bhardwaj A\ Carroll P\ Crill PM\ La~eur PM\ McCaughey JH\ Roulet NT\Suyker AE\ Verma SB\ Waddington JM\ Whiting GJ[ 0887[ The relationship between ecosystem productivity and photosyntheticallyactive radiation for northern peatlands[ Global Bioèochemistry Cycles 01] 004Ð015[

Gibson JJ\ Prowse TD\ Edwards TWD[ 0885[ Evaporation from a small lake in the continental Arctic using multiple methods[ NordicHydrolo`y 16] 0Ð13[

Glenn MS\ Woo MK[ 0886[ Spring and summer hydrology of a valley!bottom wetland\ Ellesmere Island\ Northwest Territories\Canada[ Wetlands 06] 210Ð218[

Graniero PA\ Price JS[ 0888a[ The importance of topographic factors on the distribution of bog and heath in a Newfoundland blanketbog complex[ Catena\ 25] 122Ð143[



0476

Graniero PA\ Price JS[ 0888b[ Distribution of bog and heath in a Newfoundland blanket bog complex] topographic limits on thehydrologic processes governing blanket bog development[ Hydrolo`y and Earth System Sciences\ 2] 112Ð121[

Groot A[ 0887[ Physical e}ects of site disturbance on peatlands[ Canadian Journal of Soil Science 67] 34Ð49[Halsey LA\ Vitt DH\ Trew DO[ 0886a[ In~uence of peatlands on the acidity of lakes in northeastern Alberta\ Canada[ Water Air and

Soil Pollution 85] 06Ð27[Halsey L\ Vitt D\ Zoltai S[ 0886b[ Climatic and physiographic controls on wetland type and distribution in Manitoba\ Canada[

Wetlands 06] 132Ð151[Hamlin L\ Pietroniro A\ Prowse T\ Soulis R\ Kouwen N[ 0887[ Application of indexed snowmelt algorithms in a northern wetland

regime[ Hydroloìcal Processes 01] 0530Ð0546[Hayashi M\ vanderKamp G\ Rudolph DL[ 0887a[ Water and solute transfer between a prairie wetland and adjacent uplands\ 0[ Water

balance[ Journal of Hydrolo`y 196] 31Ð44[Hayashi M\ vanderKamp G\ Rudolph DL[ 0887b[ Water and solute transfer between a prairie wetland and adjacent uplands\ 1[

Chloride cycle[ Journal of Hydrolo`y 196] 45Ð56[Hel_eld JM\ Diamond ML[ 0886[ Use of constructed wetlands for urban stream restoration] a critical analysis[ Environmental

Manaèment 10] 218Ð230[Hill AR[ 0885[ Nitrate removal in stream riparian zones[ Journal of Environmental Quality 14] 632Ð644[Hill AR\ Brooks AM[ 0885[ Coarse particulate organic matter inputs to a headwater swamp stream[ Archiv Fur Hydrobiolìe 026] 14Ð

27[Hill AR\ Devito KJ[ 0886[ HydrologicÐchemical interactions in headwater forest wetlands[ In Ecolo`y and Manaèment] Forested

Wetlands[ Lewis Publishers] Boca Raton\ FL\ 102Ð129[Hillman GR[ 0887[ Flood wave attenuation by a wetland following a beaver dam failure on a second order boreal stream[ Wetlands

07] 10Ð23[Hinton MJ\ Schi} SL\ English MC[ 0886[ The signi_cance of storms for the concentration and export of dissolved organic carbon from

two Precambrian Shield catchments[ Bioèochemistry 25] 56Ð77[Hinton MJ\ Schi} SL\ English MC[ 0887[ Sources and ~owpaths of dissolved organic carbon during storms in two forested watersheds

of the Precambrian Shield[ Biochemistry 30] 064Ð086[Hoag RS\ Price JS[ 0884[ A _eld scale natural gradient solute transport experiment in peat at a Newfoundland blanket bog[ Journal of

Hydrolo`y 061] 060Ð073[Hoag RS\ Price JS[ 0886[ The e}ects of matrix di}usion on solute transport and retardation in peat in laboratory columns[ Journal of

Contamination Hydrolo`y 17] 084Ð197[Huddart PA\ Longsta}e FJ\ Crowe AS[ 0888[ d D and d O!07 evidence for inputs to groundwater at a wetland coastal boundary in

the southern Great Lakes region of Canada[ Journal of Hydrolo`y 103] 07Ð20[Joiner DW\ La~eur PM\ McCaughey JH\ Bartlett PA[ 0888[ Interannual variability in carbon dioxide exchanges at a boreal wetland

in the BOREAS northern study area[ Journal of Geophysical Research\ BOREAS II Special Section 093"D11#] 16 522Ð16 561[Kelly CA\ Rudd JWM\ Bodaly RA\ Roulet NT\ St Louis VL\ Heyes A\ Moore TR\ Aravena R\ Dyck B\ Harriss R\ Schi} S\ Warner

B\ Edwards G[ 0886[ Increases in ~uxes of greenhouse gases and methyl mercury following ~ooding of an experimental reservoir[Environmental Science and Technolo`y 20] 0223Ð0233[

Klinger LF\ Short SK[ 0885[ Succession in the Hudson Bay lowland\ northern Ontario\ Canada[ Arctic and Alpine Research 17] 061Ð072[

La~eur PM\ McCaughey JH\ Joiner DW\ Bartlett PA\ Jelinski DE[ 0886[ Seasonal trends in energy\ water\ and carbon dioxide ~uxesat a northern boreal wetland[ Journal of Geophysical Research 091"D13#] 18 998Ð18 919[

Lapalainen E "ed[#[ 0885[ Global Peat Resources[ International Peat Society] Jyska\ Finland[Lapen DR\ Moorman B\ Price JS[ 0885[ Using ground penetrating radar to delineate subsurface features along a blanket bog:heath

land catena[ Soil Science Society of America Journal 59] 812Ð820[LaRose S\ Price JS\ Rochefort L[ 0886[ Rewetting of a cutover bog[ Hydrological assessment[ Wetlands 06] 305Ð312[Larson DL[ 0884[ E}ects of climate on numbers of northern Prairie wetlands[ Climatic Chanè 29] 058Ð079[Lavoie C\ Rochefort L[ 0885[ The natural vegetation of a harvested peatland in southern Quebec] a spatial and dendroecological

analysis[ Ecoscience 2] 090Ð000[Letts MG\ Roulet NT\ Corner NT\ Skarupa MR\ Verseghy D[ In press[ Parameterization of peatland hydraulic properties for the

Canadian Land Surface Scheme[ AtmosphereÐOcean[Liblik LK\ Moore TR\ Bubier JL\ Robinson SD[ 0886[ Methane emissions from wetlands in the zone of discontinuous permafrost]

Fort Simpson\ Northwest Territories\ Canada[ Global Bioèochemistry Cycles 00] 374Ð383[McKenzie C\ Schi} S\ Aravena R\ Kelly C\ Louis VS[ 0887[ E}ect of temperature on production of CH3 and CO1 from peat in a

natural and ~ooded boreal forest wetland[ Climatic Chanè 39] 136Ð155[McKillop R\ Kouwen N\ Soulis ED[ 0888a[ Modelling the ~ood modi_cation e}ects of a mid!sized unregulated wetland[ In New

applications in modellin` urban water systems\ Monograph 6\ James W "ed[#[ Computational Hydraulics International "CHI#] Guelph\Ontario[

McKillop R\ Kouwen N\ Soulis ED[ 0888b[ Modelling the hydrologic response of a wetland from an urban perspective[ Proceedin`sof the CSCE International Conference in Reìna\ Saskatchewan\ 1Ð4 June 0888[

McKillop R\ Kouwen N\ Soulis ED[ 0888c[ Modeling the rainfallÐruno} response of a headwater wetland[ Water Resources Research24] 0054Ð0066[

McKillop R\ Kouwen N\ Soulis ED[ In press[ A conceptual model for simulating the water balance at a headwater swamp[ AmericanSociety for Civil Enìneers\ Hydroloìcal Sciences Journal[

Metcalfe RA\ Buttle JM[ 0888[ Semi!distributed water balance dynamics in a small boreal forest basin[ Journal of Hydrolo`y 115] 55Ð76[



0477

Moore TR\ Roulet NT\ Waddington JM[ 0887[ Uncertainty in predicting the e}ect of climatic change on the carbon cycling ofCanadian peatlands[ Climatic Chanè 39] 118Ð134[

Mulamoottil G\ Warner BG\ McBean EA[ 0885[ Environmental Gradients\ Boundaries and Buffers[ Lewis Publishers] Boca Raton\ FL[National Wetlands Working Group[ 0875[ Canada|s Wetlands[ Map Folio\ Energy\ Mines and Resources Canada and Environment

Canada] Ottawa\ Ontario[National Wetland Working Group[ 0886[ The Canadian Wetland Classi_cation System\ 1nd edn\ Warner BG\ Rubec CDA "eds#[

Wetland Research Centre Publication] Waterloo\ ON\ 57p[Pietroniero A\ Prowse TD\ Peters DL[ 0888[ Hydrologic assessment of an inland freshwater delta using multi!temporal satellite remote

sensing[ Hydroloìcal Processes 02] 1372Ð1387[Prescott KL\ Tsanis IK[ 0886[ Mass balance modelling and wetland restoration[ Ecoloìcal Enìneerin` 8] 0Ð07[Prevost M\ Belleau P\ Plamondon AP[ 0886[ Substrate conditions in a treed peatland] responses to drainage[ Ecoscience 3] 432Ð433[Prevost M[ Plamondon AP\ Belleau P[ 0888[ E}ects of drainage of a forested peatland on water quality and quantity[ Journal of

Hydrolo`y 103] 029Ð032[Price JS[ 0885[ Hydrology and microclimate of a partly restored cutover bog\ Quebec[ Hydroloìcal Processes 09] 0152Ð0161[Price JS[ 0886[ Soil moisture\ water tension\ and water table relationships in a managed cutover bog[ Journal of Hydrolo`y 191] 10Ð21[Price JS[ 0887[ Methods for restoration of a cutover peatland\ Quebec\ Canada[ In Proceedin`s\ International Peat Society\ International

Peat Symposium^ Peatland Restoration and Reclamation] Techniques and Reùlatory Considerations\ Duluth\ Minnesota^ 038Ð043[Price JS\ Schlotzhauer SM[ 0888[ Importance of shrinkage and compression in determining water storage changes in peat] the case of

a mined peatland[ Hydroloìcal Processes 02] 1480Ð1590[Price JS\ Rochefort L\ Quinty F[ 0887[ Energy and moisture considerations on cutover peatlands] surface microtopography\ mulch

cover and Spha`num regeneration[ Ecoloìcal Enìneerin` 09] 182Ð201[Priestley CHB\ Taylor RJ[ 0861[ On the assessment of surface heat ~ux and evaporation using large scale parameters[ Monthly Weather

Review 099] 70Ð81[Prowse TD\ Demuth MN[ 0885[ Using ice to ~ood the PeaceÐAthabasca Delta\ Canada[ Reùlated Rivers] Research and Manaèment

01] 336Ð346[Prowse TD\ Aitken B\ Demuth MN\ Peterson M[ 0885[ Strategies for restoring spring ~ooding to a drying northern delta[ Reùlated

Rivers] Research and Manaèment 01] 126Ð149[Quinton WL\ Marsh P[ 0887a[ A conceptual framework for runo} generation in a permafrost environment[ Hydroloìcal Processes

02] 1452Ð1470[Quinton WL\ Marsh P[ 0887b[ The in~uence of mineral earth hummocks on subsurface drainage in the continuous permafrost zone[

Permafrost and Peri`lacial Proceedin`s 8] 102Ð117[Quinton WL\ Marsh P[ 0887c[ Melt water ~uxes\ hillslope runo} and stream ~ow in an arctic permafrost basin[ Proceedin`s\ 6th

International Conference on Permafrost\ 12Ð16 June\ Yellowknife^ 810Ð815[Quinton WL\ Roulet NT[ 0887[ Spring and summer hydrology of a subarctic patterned wetland[ Arctic and Alpine Research 29] 174Ð

183[Rothwell RL\ Silins U\ Hillman GR[ 0885[ The e}ects of drainage on substrate water content at several forested Alberta peatlands[

Canadian Journal of Forest Research 15] 42Ð51[Roulet NT\ Moore TR[ 0884[ The e}ect of forestry drainage practices on the emission of methane from northern peatlands[ Canadian

Journal of Forest Research 14] 380Ð388[Roulet NT\ Crill PM\ Comer NT\ Dove A\ Bourbonniere R[ 0886[ CO1 and CH3 ~ux between a boreal beaver pond and the atmosphere[

Journal of Geophysical Research 091"D13#] 18 202Ð18 208[Rouse WR[ 0887[ A water balance model for a subarctic sedge fen and its application to climatic change[ Climate Chanè 27] 196Ð123[Sagot C\ Rochefort L[ 0885[ Spha`num desiccation tolerance[ Cryptoàmie\ Bryolo`y and Lichenolo`y 06] 060Ð072[Schi} SL\ Aravena R\ Trumbore SE\ Hinton MJ\ Elgood R\ Dillon PJ[ 0886[ Export of DOC from forested catchments on the

Precambrian Shield of Central Ontario] clues from C!02 and C!03[ Bioèochemistry 25] 32Ð54[Schlotzhauer SM[ 0887[ Modelin` soil water dynamics in cutover peat _elds\ Quebec] a peat!ditch recharè system[ MES thesis\

Department of Geography\ University of Waterloo\ Waterloo\ ON[Schlotzhauer SM\ Price JS[ 0888[ Soil water ~ow dynamics in a managed cutover peat _eld\ Quebec] _eld and laboratory investigations[

Water Resources Research 24] 2564Ð2572[Schreader CP\ Rouse WR\ Gri.s TJ\ Boudreau LD\ Blanken PD[ 0887[ Carbon dioxide ~uxes in a northern fen during a hot\ dry

summer[ Global Bioèochemistry Cycles 01] 618Ð639[Silins U\ Rothwell RL[ 0887[ Forest peatland drainage and subsidence a}ect soil water retention and transport properties in an Alberta

peatland[ Soil Science Society of America Journal 51] 0937Ð0945[Silins U\ Rothwell RL[ 0888[ Spatial patterns of aerobic limit depth and oxygen di}usion rate at two peatlands drained for forestry in

Alberta[ Canadian Journal of Forest Research 18] 0Ð7[Sklash MG\ Beven KJ\ Gilman K\ Darling WG[ 0885[ Isotope studies at Plynlimon\ Wales\ UK[ Hydroloìcal Processes 09] 810Ð833[Sobolewski A[ 0885[ Metal species indicate the potential of constructed wetlands for long!term treatment of metal mine drainage[

Ecoloìcal Enìneerin` 5] 148Ð160[Tarnocai C[ 0879[ Canadian wetland registry[ In Proceedin`s\ Workshop on Canadian Wetlands\ Rubec CDA\ Pollett FC "eds#[

Ecological Classi_cation Series No[ 01\ Lands Directorate\ Environment Canada] Ottawa\ Ontario\ 8Ð29[Tarnocai C[ 0887[ The amount of organic carbon in various soil orders and ecological provinces in Canada[ In Soil Processes and the

Carbon Cycle\ Lal R\ Kimble JM\ Follet RF\ Stewart BA "eds#[ CRC Press] Boca Raton\ FL\ 70Ð81[Taylor CH[ 0886[ Runo} processes in temperate headwater wetlands[ In Ecolo`y of Wetlands and Associated Systems\ Majumdar SK\

Miller EW\ Brenner FJ "eds#[ The Pennsylvania Academy of Science] Pittsburgh\ 057Ð070[Van der Kamp G\ Stolte WJ\ Clark RG[ 0888[ Drying out of small prairie wetlands after conversion of their catchments from cultivation

to permanent brome grass[ Hydroloìcal Sciences Journal 33] 276Ð287[



0478

Van Seters T[ 0888[ Linkin` the past to the present] the hydroloìcal impacts of peat harvestin` and natural reèneration on an abandonedcut!over peat bo`\ Quebec[ MES thesis\ Department of Geography\ University of Waterloo\ Canada^ 64 pp[

Vardy SR\ Warner BG\ Aravena R[ 0887[ Holocene climate and the development of a subarctic peatland near Inuvik\ NorthwestTerritories\ Canada[ Climatic Chanè 39] 174Ð202[

Verseghey DL\ McFarlane NA\ Lazare M[ 0882[ CLASS * a Canadian land surface scheme for GCMs\ II[ Vegetation model andcoupled runs[ International Journal of Climatolo`y 02] 236Ð269[

Vitt DH[ 0883[ An overview of factors that in~uence the development of Canadian peatlands[ Memoirs of the Entomoloìcal Society ofCanada 058] 6Ð19[

Waddington JM\ Roulet NT[ 0885[ AtmosphereÐwetland carbon exchanges] scale dependency of CO1 and CH3 exchange on thedevelopmental topography of a peatland[ Global Biochemistry Cycles 09] 122Ð134[

Waddington JM\ Roulet NT[ 0886[ Groundwater ~ow and dissolved carbon movement in a boreal peatland[ Journal of Hydrolo`y 080]011Ð027[

Waddington JM\ Roulet NT\ Swanson RV[ 0885[ Water table control of CH3 emission enhancement by vascular plants in borealpeatlands[ Journal of Geophysical Research * Atmosphere 090] 11 664Ð11 674[

Waddington JM\ Gri.s TJ\ Rouse WR[ 0887[ Northern Canadian wetlands] net ecosystem CO1 exchange and climatic change[ ClimaticChanè 39] 156Ð164[

WindMulder HL\ Rochefort L\ Vitt DH[ 0885[ Water and peat chemistry comparisons of natural and post!harvested peatlands acrossCanada and their relevance to peatland restoration[ Ecoloìcal Enìneerin` 6] 050Ð070[

Woo M!K\ Waddington JM[ 0889[ E}ects of beaver dams on subarctic wetland hydrology[ Arctic 32] 112Ð129[Woo M!K\ Xia R[ 0885[ E}ects of hydrology on the thermal conditions of the active layer[ Nordic Hydrolo`y 16"0Ð1#] 018Ð031[Woo M!K\ Young K[ 0887[ Characteristics of patchy wetlands in a polar desert environment\ Arctic Canada[ Proceedin`s\ 6th

International Conference on Permafrost\ 12Ð16 June\ Yellowknife^ 0030Ð0035[Worthy DEJ\ Levin I\ Trivett NBA\ Kuhlmann AJ\ Hopper JF\ Ernst MK[ 0887[ Seven years of continuous methane observations at

a remote boreal site in Ontario\ Canada[ Journal of Geophysical Research * Atmosphere 092] 04 884Ð05 996[Zoltai SC\ Vitt DH[ 0884[ Canadian wetlands * environmental gradients and classi_cation[ Veètatio 007] 020Ð026[