Ecosystem services classification: A systems ecology perspective of the cascade framework

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Ecological Indicators

j ou rn a l h om ep a g e :w w w . e l s e v i e r . c o m / l o c a t e /e c o l i n d

Original Articles

Ecosystem services classiﬁcation: A systems ecology perspective of the cascade framework

Alessandra La Notte

^a,∗

, Dalia D’Amato

^b,∗

, Hanna Mäkinen

^c

, Maria Luisa Paracchini

^a

, Camino Liquete

^a

, Benis Egoh

^d,e

, Davide Geneletti

^f

, Neville D. Crossman

^g

aEuropeanCommission-JointResearchCentre,DirectorateD–SustainableResources,ViaEnricoFermi2749,21027Ispra,VA,Italy

bUniversityofHelsinki,DepartmentofForestSciences,Latokartanonkaari7,Helsinki,00014,Finland

cLappeenrantaUniversityofTechnology,SchoolofEnergySystems,SustainabilityScience,Saimaankatu11,15140Lahti,Finland

dCouncilforScientiﬁcandIndustrialResearch,NaturalResourcesandTheEnvironment,POBox320,Stellenbosch7599,SouthAfrica

eSchoolofAgricultural,EarthandEnvironmentalSciences,UniversityofKwaZulu-Natal,27PrivateBagX01,Scottsville3209,SouthAfrica

fUniversityofTrento,DepartmentofCivil,EnvironmentalandMechanicalEngineering,ViaMesiano77,38123Trento,Italy

gCSIROLandandWater,WaiteCampus,Adelaide,SouthAustralia,5064,Australia

a r t i c l e i n f o

Articlehistory:

Received18April2016 Receivedinrevisedform 17November2016 Accepted18November2016 Availableonline9December2016 Keywords:

Systemsecology Ecosystemfunctioning Cascadeframework Ecologicaltheory

Ecosystemserviceclassiﬁcation

a b s t r a c t

Ecosystemservicesresearchfacesseveralchallengesstemmingfromthepluralityofinterpretationsof classificationsandterminologies.Inthispaperweidentifytwomainchallengeswithcurrentecosystem servicesclassificationsystems:i)theinconsistencyacrossconcepts,terminologyanddefinitions,and;ii) themixupofprocessesandend-statebenefits,orflowsandassets.Althoughdifferentecosystemservice definitionsandinterpretationscanbevaluableforenrichingtheresearchlandscape,itisnecessaryto addresstheexistingambiguitytoimprovecomparabilityamongecosystem-service-basedapproaches.

Usingthecascadeframeworkasareference,andSystemsEcologyasatheoreticalunderpinning,we aimtoaddresstheambiguityacrosstypologies.Thecascadeframeworklinksecologicalprocesseswith elementsofhumanwell-beingfollowingapatternsimilartoaproductionchain.SystemsEcologyisa long-establisheddisciplinewhichprovidesinsightintocomplexrelationshipsbetweenpeopleandthe environment.Wepresentarefreshedconceptualizationofecosystemserviceswhichcansupportecosys- temserviceassessmenttechniquesandmeasurement.Wecombinethenotionsofbiomass,information andinteractionfromsystemecology,withtheecosystemservicesconceptualizationtoimprovedeﬁni- tionsandclarifyterminology.Wearguethatecosystemservicesshouldbedeﬁnedastheinteractions(i.e.

processes)oftheecosystemthatproduceachangeinhumanwell-being,whileecosystemcomponentsor goods,i.e.countableasbiomassunits,areonlyproxiesintheassessmentofsuchchanges.Furthermore, SystemsEcologycansupportare-interpretationoftheecosystemservicesconceptualizationandrelated appliedresearch,wheremoreemphasisisneededontheunderpinningcomplexityoftheecological system.

1. Introduction

Ecosystem services is now widely used among scientists and policymakers tohighlight the importanceof the environment (including biodiversity) in sustaining human livelihoods (Convention on Biological Diversity, 2010, 1998; Costanza and Kubiszewski,2012;Maesetal.,2016).Animportantmilestoneof ecosystemserviceresearchwastheMillenniumEcosystemAssess-

∗Correspondingauthors.

E-mailaddresses:alessandra.la-notte@jrc.ec.europa.eu(A.LaNotte), dalia.damato@helsinki.ﬁ(D.D’Amato).

ment (MA, 2005)which made prominentthe idea that human well-being depends on ecosystems,and that suchlinkages can betrackedandframedthroughthenotionofecosystemservices.

TheMAfoundthatmorethan60%ofecosystemservicesisbeing degradedortransformedendangeringfuturehumanwell-being.

Ecosystemservicesresearchhassinceprogressedatdifferent levels—fromtheoreticalconceptualizationtopracticalapplications (seeBraatanddeGroot,2012;Egohetal.,2012;Seppeltetal.,2011;

Potschinetal.,2016forareview).Thisworkhasbeensupportedby severalinternationalinitiativessuchasTheEconomicsofEcosys- tem and Biodiversity(TEEB, 2010), the UK National Ecosystem Assessment(UKNEA,2011)andseveralEuropeanUnionresearch

http://dx.doi.org/10.1016/j.ecolind.2016.11.030

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projects.¹Inaddition,someorganizationshavesupportedthispro- cesswithmodelingtoolssuchastheUSNaturalCapitalProject withtheIntegrated ValuationofEcosystemServicesand Trade- offs(InVEST)tool.Theprivatesectorhavealsoadoptedtheconcept throughinitiativessuchastheNaturalCapitalCoalition(NCC),the WorldBank’sWealthAccountingandtheValuationofEcosystem Services(WAVES),theaccountingsystemdevelopedbytheLondon Group,whichisalsobeingadoptedbytheUnitedNationsEnviron- mentalProgram(UNEP).

However,therehasbeeninconsistencyindevelopingaframe- work within which such research and policy assessments are carriedout.TheheMA(2005)andsubsequentecosystemservices literature(BoydandBanzhaf,2007; Fisheretal., 2009;Haines- YoungandPotschin,2012;LandersandNahlik,2013;Staubetal., 2011;Wallace,2007)havedevelopedmanydifferentconceptual andempiricalframeworksandassessmentofchangesinecosys- tems,theirconsequencesforhumans,andactionsforsustainable useof these ecosystems(Albert et al., 2015). The existence of numerousecosystemserviceconceptualizationsandclassification systemshasledtoapluralityintheinterpretationofecosystem servicesandrelatedterminologyanddefinitionswhenitcomesto applications(Boeremaetal.,2016).Largedifferencesininterpreta- tionarefoundinthemeaningofbiophysicalstructure,ecological functions,intermediateservicesandfinalservices(e.g.Landersand Nahlik,2013;Mononenetal.,2016;Spangenbergetal.,2014;UK NEA,2011;TEEB,2010).Theconsequenceofsuchdifferencesisthe ecosystemserviceclassificationsystemshavepoorcorrespondence ofserviceswithbenefitsandblurreddistinctionsbetweeninterme- diateandfinalservices.Amongthese,theCommonInternational ClassificationforEcosystemServices(CICES),proposedbytheEuro- pean Environment Agency, hasbecome an important frame of referenceforecosystemservicesresearch(Maesetal.,2014).CICES andmostecosystemservicesliteraturearebasedonandinfluenced bythecascadeframeworkproposedbyHaines-Young&Potschin in2010(Haines-YoungandPotschin,2010;PotschinandHaines- Young,2016).Thepurposeofthecascadeframeworkisinfactto showthepathwayofecosystemservicesfromecologicalstructures andprocessestohumanwell-being.

In this context, theneed to develop a framework to assess ecosystemservices isa priorityin ecosystemservices research.

Althoughindividualinterpretationsenrichtheresearchlandscape, theambiguitymustbeaddressedsothatamorerigorousframe- workforecosystemservicescanbedevelopedandadopted.Such a framework would improve comparability among ecosystemservice-based approaches and would provide a standardized approachforecosystemassessmentsatglobalandnationalscales.

Thefurtherevolutionofecosystemservicesconceptsandframe- workscoulddrawfromthefield ofsystemsecology whichcan provideinsightsintoourunderstandingofthedifferentaspectsof ecosystemfunctioningthatcontributestoecosystemservices.This interdisciplinaryfieldofsystemsecologyadoptsaholisticapproach tothestudyofecologicalandhumansystems.Conceptsfromeco- logicaltheoryhavebeenalreadydiscussedinpreviousliterature inrelationtoecosystemservices,e.g.ecologicalintegrityandcom- plexity,resilience(Kremen,2005;Brand,2008).Ourpaperaims tosystematicallyadoptkeyconceptsfromsystemsecologytore- defineecosystemservicesandtherelatedcascadeframework.The contributionofourpaperistopresentarefreshedconceptualiza- tionofecosystemservicesthroughthelensofsystemsecology.

1e.g.RUBICODE(RationalizingBiodiversityConservationinDynamicEcosys- tems),SCALES(SecuringtheConservationofbiodiversityacrossAdministrative Levelsandspatial,temporal,andEcologicalScales),OpenNESS(Operationalization ofNaturalCapitalandEcosystemServices)andESMERALDA(EnhancingecoSysteM sERvicesmAppingforpoLicyandDecisionmAking)

Weﬁrstlyidentifythemainchallengesassociatedwiththevar- iousinterpretationsofthecascadeframework(Section2.1)andof theexistingclassiﬁcationsystemswhosestructureandmeaning doesdependonthechosentheoreticalframework(Section2.2).

Secondly,weintroducekeyconceptsfromthedisciplineofsystems ecology(Section3)toaddresstheidentiﬁedchallenges(Section4).

Weﬁnallyconcludebydiscussingthecontributionofourrefreshed conceptualizationofecosystemservices(Section5).

2. Currentchallengesinecosystemservicesresearch 2.1. Challengeswiththeuseoftheecosystemservicescascade

The cascade framework proposed by Haines-Young and Potschin(2010)linksnaturalsystemstoelementsofhumanwell- being, following a pattern similar to a production chain: from ecologicalstructuresandprocessesgeneratedbyecosystems,tothe servicesandbeneﬁtseventuallyderivedbyhumans.Theadvantage ofthisframework istoeffectivelycommunicatesocietaldepen- denceonecosystems.

Challenges arise when applying this cascade framework in practice,duetothesimultaneouspresenceintheframeworkofbio- centeredandhuman-centeredspheres.Thismeansthatecosystem servicesassessmentsinclude:

•observationsfroma bio-centredor holisticapproach-i.e.bio- physical structures and processes/functions belonging to the ecologicalsphereandwhichareconsideredasawhole,

•observationsfromareductionist orhuman-centredapproach- i.e.ecosystemserviceswhichareprojectedtowardsthehuman end-usesideindividually.

Thischallengeisevidentwhenwetrytomeasureecosystem services,whicharecategorizedandaccountedforindividually.²

Inaddition,differentdefinitionsofecosystemservicesandin particular oftheelements inthe cascadeframework are found intheliterature:biophysicalstructure,process,function,service, benefit.³Asanexample,Table1summarizesthedefinitionspro- videdinrecentecosystemservicesstudies.Forinstance,ecosystem structure is often poorlydistinguishedfrom processes. Wallace (2007,p.237)proposesthat‘animportantdistinction[between thetwo]isthattheformeraregenerallytangibleentitiesdescribed intermsofamount,whilethelatterare[...]generallydescribedin termsofrates’.

Furthermore,thewordfunctionisgenerallyusedinterchange- ablywithecologicalprocessand/orecosystemservice.According toJax(2005),theterm‘function’isoftenusedtooambiguously.

Ecosystemservicesaregenerallydefinedas theecosystem pro- cessesconsideredusefultohumans(MA,2005;TEEB, 2010).In the same light, some studies(ref. Table1) that have assessed, mappedorvaluedecosystemservices,useservicesand benefits assynonyms. Benefitsarein somecasesconsideredastangible naturalresourcesderived fromprovisioningservices(e.g.crops, wood,water),orsomeregulatingservices(e.g.cleanwaterformul- tipleusesprovidedbywaterpurification).Benefits,however,can alsobeintangible(e.g.recreationopportunitiesofferedbynature).

2Notethatsomeauthors,e.g.Mononenetal.(2016)havesuggestedtohighlight theprocess-likenatureofecosystemservicesdeliveryassocio-ecologicalsystems, thusmaintainingtheholisticapproachonthefocus.

3Thecascademodeldoesindeedinclude,after‘benefit’,alsothe‘value’stepthat assignstobenefitsaquantificationinmonetaryterms.Theeconomicvaluationof ecosystemservicesisafieldofresearchandapplicationsthatdoesnotaffectthe specificconceptualanalysisproposedinthispaper.Inordertokeepfocusedonthe mainobjectivesofthepaper,wethuschoosenottoincludethe‘value’boxatthis stage.

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Table1

Deﬁnitionsandexamplesofecosystemservicesterminologyaccordingtoselectedpeer-reviewedliterature.

Author&

proposed application

Biophysicalstructure Process Function Ecosystemservices Good Beneﬁt

Batemanetal.

(2011)

e.g.animals,birds, plantsandtheir connections,etc.

e.g.nutrientcycling Primaryecological processes

Flowofservices (outcomeofstructure andprocesses) providedbyecological assetsinsome assessmentperiod.

Anyobjector constructwhich generateshuman wellbeing(physical andnon).

Thechangeinhuman well-beinggeneratedbya good(use-valueandnon).

Thesamegoodcan generatedifferentvalues, dependingonthecontext.

Boydand Banzhaf(2007)

Seedeﬁnitionfor

‘process’

Biological,chemical, andphysical interactionsbetween ecosystem

components.Functions andprocessesarenot end-products;theyare intermediatetothe productionofﬁnal ecosystemservices.

Seedeﬁnitionfor

‘process’

Theuseofecological assetoversometime period.

Thingsdirectly enjoyedor consumedby households.

Abeneﬁte.g.recreation, arisesfromthejointuseof ﬁnalecosystemservices andconventionalgoods andservices.

Fisheretal.

(2009)

Seedeﬁnitionfor

‘ecosystemservices’

Seedeﬁnitionfor

Theyareecologicalin nature,inthat aestheticvalues, culturalcontentment andrecreationarenot ecosystemservices.

Ecosystemservicesare ecologicalcomponents, functionsand/or processes,aslongas therearehuman beneﬁciaries.

na Abenefithasanexplicit impactonchangesin humanwellfare,likemore food,betterhiking,less flooding.Forexample, aesthethicvalues,cultural contentmentand recreationarebenefitand notjustafunctionofthe ecosystem,butinclude otherinputslikehuman capital,builtcapital,etc.

Maesetal.

(2016)

Thearchitectureofan ecosystemasaresultof theinteraction betweentheabiotic, physicalenvironment andthebiotic communities,in particularvegetation

Anychangeorreaction whichoccurswithin ecosystems,physical, chemicalorbiological.

Ecosystemprocesses includedecomposition, production,nutrient cycling,andﬂuxesof nutrientsandenergy

Subsetofthe interactionsbetween biophysicalstructures, biodiversityand ecosystemprocesses thatunderpinthe capacityofan ecosystemtoprovide ecosystemservices

Thedirectandindirect contributionsof ecosystemstohuman wellbeing(TEEB,2010).

Theactuallyused service.

Theconcept

’ecosystemgoods andservices’is synonymouswith ecosystemservices.

Positivechangein wellbeingfromthe fulﬁlmentofneedsand wants(TEEB,2010)

Müllerand Burkhard (2012)

Biophysicalstructures andprocesses (ecosystemproperties) arelinkedinthe cascadecomponentof ecosystemfunctions.

Theyareunderstoodas thebasicproducersof ecosystemservices.

Seedeﬁnitionfor

‘biophysicalstrucuture’

Ecologicalintegrity Directandindirect contributionsof ecosystemstructures andfunctions

na intendedassocial, economicandpersonal well-being

Mononenetal.

(2016)

Biophysicalstructures thatcreatethebasisfor functioningofthe ecosystem.Spatial perspective.

na Functioningof

ecosystemthatis neededtoproduce ecosystemservices.

Temporalperspective.

na Theusedshareof thepotentialof ecosystemservices.

Beneftscanbealso non-material.

Economic,social,health (physicalorspiritual)and intrinsicvalueofthe beneﬁt.

Spanenberg etal.(2014)

Biophysicalstructure orprocessincludes habitattype

Seedeﬁnitionfor

‘biophysicalstrucuture’

e.g.woodproduction Collectingor harvestingwood(that isthehumanactivityof withdrawingthe naturalasset)

Contributionto aspectsof well-beingsuchas healthandsafety

Willingnesstopayfor morewoodlandor harvestableproducts.

TEEB(2010) Biophysicalstructure orprocess=vegetation coverorNetPrimary Productivity

seeBiophysical structure

Thepotentialthat ecosystemshaveto deliveraservicewhich inturndependson ecologicalstructure andprocesses.

Conceptualizationsof the“usefulthings”

ecosystems“do”for people,directlyand indirectly

na Welfaregainsgeneratedby ecosystemservices

Wallace(2007) na Thecomplex

interactions(events, recreationsor operations)among bioticandabiotic elementsof

ecosystemsthatleadto adeﬁniteresult.

Seedeﬁnitionfor

‘process’

Beneﬁtsthatpeople obtainfrom ecosystems;the outcomessought throughecosystem management.

na Preferredend-statesof existence,includingthose requiredforhuman survivalandreproductive success,whichtaken togethercircumscribe humanwell-being.These excludeintrinsicvalue.

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Haines-YoungandPotschin(2009,p.17)proposea‘pragmaticway forward’,statingthat‘themainissueistoensuretherigorofthe outputsfromouranalysisandnotbecomepreoccupiedwithdef- initions,henceeffortsshouldbedirectedto:achievingconsistent valuationandnodoublecounting’.

Moreunifiedandshareddefinitions,however,canbehelpfulin ensuringtherigorofpracticalassessments,andallowadegreeof comparabilityamongstudies.Inparticular,itisimportanttodis- tinguishbetweenservice,process,andbenefit.BraatanddeGroot (2012)arguedthatecosystemservicescontain‘theproductcom- ponent(traditionallycalled“goods”)’,buttheysuggestthat‘inthe nextstageofdevelopmentoftheconcept,thedistinctionbetween goodsandservicesshouldbere-established’.Whenreferringto thecascadeframework,theterminologyincludesbenefitsrather thangoods.Thechallengeofseparatingservicesfromgoodsand/or benefitsisfurtherexploredinthenextsection.

2.2. Challengesinthecurrentecosystemservicesclassifications Anyapplicationofanecosystemservice-basedapproachstarts withchoosing the servicestobe assessed (and valued)from a listofservices,i.eaclassification system.Classificationsystems areusually based ona theoretical framework whoseprinciples and conceptsare reflected inthemeaning andstructure ofthe itemspresented. It is thusimportant toexplore themainclas- sification systems, in order to highlight the embeddednotions theystate.Forexample, theMillenniumEcosystemAssessment (2005)wasthefirsttoattempttogroupecosystemservicesinto fourcategories:provisioningservices(e.g.food,fibers,fuel,genetic resources);regulatingservices(e.g.,waterpurificationandregula- tion,climateregulation,extremeeventsanddiseasemitigation);

supportingservices(e.g.,primaryproductionandnutrientcycling);

andculturalservices(e.g.,eco-tourismandrecreation,aesthetic andspiritualvalues).Thiscategorizationprovidedasoundbasisto launchecosystemservicesresearchandapplications,butitdoesnot constituteapropertaxonomy.Inthecascadeframework(Haines- YoungandPotschin,2012),supportingservicesareconsidereda

‘function’ratherthana‘service’.FollowingtheMA,theTEEBclas- sification(2010)alsoexplicitlyreferredtothecascadeframework butrefinedthedistinctionbetweenservicesandbenefits.Theidea ofsupportingservicesinTEEBwasnotfurtherdeveloped.Instead anew‘habitatservices’groupwasintroduced,including‘mainte- nanceoflifecycles’and‘maintenanceofgeneticdiversity’

Sincesomeecosystemservicecategoriesoverlap,thereisarisk of double countingin valuation,which therefore requiresclear separationbetweenintermediateandfinalservice.TheUSEnviron- mentalProtectionAgencyhasproposedadditionalclassifications toavoiddouble counting.Theseinclude FinalEcosystemGoods andServicesClassificationSystem(FEGS-CS)(LandersandNahlik, 2013)andtheNationalEcosystemServicesClassificationSystem (NESCS)(Rhodes,2015).In bothclassificationsystemsthemain focusisonbenefitsandbeneficiaries.Thisisinlinewiththestudy byBoydandBanzhaf(2007)thatsuggesttoaccountfor‘compo- nentsofnaturedirectlyenjoyed,consumedorusedtoyieldhuman well-being’.FEGS-CSclassificationproposestwocriteriatodefine goodsandservices:i)thepotentialgoodorserviceisvaluedbya beneficiary,and;ii)thepotentialgoodorserviceisconnectedtoat leastthehydrosphereandlithosphere.InFEGS-CSprocessessuchas photosynthesisorcarbonsequestrationarelabeledalltogetheras

‘ecosystemstructuralcomponents’andconsideredasintermediate goodsandservices.Theseareexcludedbecausetheyarenotdirectly usedbyhumans.Similarly,NESCSclassificationrepresentsdistinct pathwaysthroughwhichfinalecosystemservicesenterhumansys- tems.Thisclassificationapproachfocusesonendcategoriesofuses andusers,andisalignedwiththeNorthAmericanationalaccounts classificationsystem.NESCSemphasizestheconnectionbetween

the‘end-productofnature’andthehuman‘directuses’astangible andintangiblebeneﬁts.

CICESisoneofthemostpopularclassificationscurrentlyand is beingusedbyscientists and policymakersaroundtheglobe but particularlyfromEurope.Similartothe TEEBclassification, CICESdoesnotincludetheMA(2005)‘supportingservices’,but mergestheTEEB(2010)‘habitatservices’withregulatingservices, inacategorycalled‘regulatingandmaintenanceservices’.Com- paredtoFEGS-CSandNESCS,CICESdoespromoteacleardistinction betweenecosystemservicesandecosystembenefits.Inthelatest versionofthecascadeframeworkthatunderpinsCICES(Potschin andHaines-Young,2016),ecosystemservicesareexplicitlyindi- catedasfinal services,whilebiophysicalstructure andfunction areindicatedassupportingorintermediateservices.Finalecosys- temservicesarethecontributionsthatecosystemsmaketohuman well-beingasflows.Ecosystemgoodsandbenefitsarecreatedor derivedbypeoplefromfinalecosystemservices.

ThedifferencesbetweenFEGS-CSandCICESaresubtleandare explainedwiththeassistanceofFig.1:a)thecascadeframework thatconstitutesthetheoreticalbackgroundofCICES,and;b)the conceptualframeworkoftheFEGS-CS.FEGS-CSplacesemphasis onthebeneﬁts,beneﬁciariesandthesocio-economicsystem,while CICESplacesgreateremphasisontheecologicalsystem.Infactwe needtoaddanadditionalbox(i.e.assets/commodities)inthecas- cadeframeworktohaveamoreconsistentviewofthetwomodels.

Inthisadditionalboxthebenefitsenterintoaproductionprocess thatmakesitamarketablegood,aneconomicasset,acommod- ity.Althoughecosystemservicesareidentifiedconsideringhuman needsanddemand,wechooseinFig.1atohavethesocio-economic systemsstartingatthe‘benefit’boxbecauseatthisstagethereal usecantakeplaceandbecausethisistheonlywaytoconsistently comparethetwotheoreticalframeworks.Bycomparingthesetwo classificationstoeach otherand tothe cascadeframework, we observethatFEGS-CSclassificationregardsdifferentbenefitsrather thanecosystemservices.

Themostappropriateclassificationsystemshouldbechosen basedonitsfit-for-purpose(Heinketal.,2015;Spangenbergand Settele,2010),i.e.whethertheecosystemserviceanalysisintends tofocusmoreonecologicalsystems(e.g.consideringimpactson andpressuresfromthesocio-economicside)oronsocio-economic systems(e.g.thebenefitsderivedbysociety).Itishoweverimpor- tanttobeawareoftheexistinglimitationsofeachclassification system.

3. Thenatureofecosystemservices:asystemsecology perspective

Inthetheoryofsystemsecology,Jørgensen(2012)proposed threefundamentalnotionsasthebasisofecologicalsystems:1) biomass,2)interactionand3)informationinecologicalnetworks.

In this section we argue that ecosystem services have in fact beenconceptualizedaseither(bio)mass,informationorinteraction (Fig.2).Weadoptthefollowingdeﬁnitionsofthesekeyconcepts.

Biomass is biological material derived from living or dead organisms.Thequalityaspectofbiomassisalsorelevant,e.g.

basedonproteinsynthesisandevolution.

Interactionoccursinanetworkascomponentshaveaneffect upononeanother.Interactionsarethereforetherelationships betweenandamongbioticandabioticcomponents,sometimes characterizedbyatemporalpattern;suchrelationshipscanbe bi-ormulti-directional,asopposedtotheunidirectionalcausal effectofinformation.Inecologicalnetworks,interactionsmight resultinemergentpropertiesofthesystem.Emergingproper- tiesinasystemcannotbepredictedorexplainedbythesum

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Fig.1. AcomparisonofCICESandFEGSclassiﬁcations.

Fig.2. Aschematicrepresentationofbiomass,information,interaction.

of thecomponents alone, because the latter do not exhibit suchpropertiesthemselves(Edsonetal.,1981;Odum,1977).

Social behaviourin animalsisanexample,suchas‘theabil- ityoflargepopulationsofsimple,identicalunits(forexample, spinmagnets)toself-organize,formpatterns,storeinformation, andreach“collectivedecisions”(ParrishandEdelstein-Keshet, 1999).Interactionsinanecologicalnetworkcanalsobedeﬁned asecologicalprocesses.

Informationcanbeconsideredasub-categoryofinteraction;

informationis“conveyedorrepresentedbyaparticulararrange- mentorsequenceofthings,includingforexample,genetically transmitted information” (Oxford Dictionary Online, 2014).

Information can inﬂuence (intentionally or not) the forma- tion ortransformation of other patterns.Organismsinteract withtheirenvironment notjust byexchangingmaterial and energyastraditionallyviewedinEcology,butalsobyexchang-

inginformation (Dusenbery,1992).Theprocess ofacquiring informationinvolvesamechanisticphaseofinformationcap- turebyareceptor,suchasasensoryorgan,andafunctional phaseofinformationde-codiﬁcation.Thisistheabilitytorecog- nizeandprocessthatinformationas‘knowledge’(Guilfordand Dawkins,1991).Consequently,exchangeofinformationoccurs betweentwo(ormore)organismswhenthe‘receiver’organ- ism(s)is abletocaptureand processtheinformation ofthe

‘sender’.Whileinformationplaysaroleinthegenerationofall ecosystemservices(e.g.geneticinformation),inthisarticlewe speciﬁcallydeﬁneinformationastheonehumansreceiveand process.

Anorganismexpressesandconveysbiomass,informationand interactionsviaitsgenotypeand/orphenotype(Fig.2).Werefer heretotheextendedphenotype(Dawkins,1982),whichincludes theappearanceof anorganism(morphology,development,bio-

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Fig.3. Thenatureofbiomass,informationandinteractioninSystemsEcology,and thehumanunderstandingandmastershipoftheseconcepts.

chemicalandphysiological processes,etc.)aswellasproperties externaltothebody(phenology,behaviour,productsofbehaviour).

Forexample,thesilkproducedbythesilkworm(Bombyxmori)is essentiallybiomass,derivedfromitschrysalisduringthemeta- morphosis.Therefore,theecosystemservice(inthiscasethesilk producedbythesilkworm)isnotadirectproductofitsbodymass, butratheranexpressionofitsphenotype.

Based on the given definitions of biomass, information and interaction,wecanexaminethecurrentclassificationofecosys- tem services.Most provisioning services are conceptualized as (bio)masse.g.food,fiber,water(deGrootetal.,2002;MA,2005;

TEEB, 2010). Genetic resources represent an exception among provisioningservices,sinceweconsiderthemasinformation.In fact,the genotypeor phenotypeofan organismcancontribute to develop drugs or to bioengineering. Regulating services are basedoninteractions amongbiotic andabioticelementsofthe ecosystems:forexamplewaterpurificationderivesfromtheover- allmechanicalandchemicalcapacityofabioticsoil,soilbiotaand vegetationtotrapand‘convert’sediments,nutrients,pollutantsor pathogens.Culturalservicesderivefrominformation.Forexample, we are able toreceive the information from an amenity land- scapegiventhehumanabilitytoperceive(receptor)andappreciate beauty(decodificationandinterpretation).Thisinformationmight influencehumans,forexampletriggeringinspiration,aphysiolog- icalrelaxation,asenseoffulfilment,oraspiritualexperience.

Drawingfromthermo-dynamics,Jørgensen(2012,chapter13) proposesthefollowingideas:growthofmatterislimitedbyenergy inputandavailabilityofinorganicelements.Thegrowthofinfor- mationandinteractionsinnetworksisdrivenbyevolution(thus linkedtodiversity)andhaspotentialtoexpand(Faithetal.,2010) (Fig.3):informationandinteractionshaveoverallincreasedinthe historyoflivingorganisms.Unlikematterandenergy,information andinteractionscandisappearwithouttracewhenthematerial support(biomass)isdestroyed.⁴ Thus,biomass,informationand interactionsarecharacterizedbyincreasingcomplexityandoper- ateatdifferenthierarchicallevels.Biodiversityisatthebasisofthis complexity:themorediversity,themoreinformationandinterac- tions.TheverydeﬁnitionofBiodiversity(ConventiononBiological Diversity,1992)referstothehierarchicalorganizationofallorgan- isms aswellasthefunctional characteristicsof each level.The processesatoneleveloforganizationdeterminetheconditionsin thenextlevel,whilehigherlevelsregulateandcontrollowerlevels byfeedback.Forexample,speciesdiversityinﬂuencesecosystem propertiesandfunctioning,andviceversa.Ithastobenotedthat

4NotethatgeneticinformationisstoredinDNAandtransmittedacrossgenera- tions.

thisisanartificialcategorization,sinceinnaturethehierarchyis notclearlydefined,butmorefluid.

4. Refreshingtheconceptualapproachtoecosystem services

4.1. Re-definingthecascadeframeworkbasedonsystemecology Basedonthedefinitionsabove,weaddressthechallengesin ecosystemservicesresearchidentifiedinsection2.Wecombine thenotionsofbiomass,informationandinteractionwithecosys- temservicesconceptualizationtoimprovedefinitionsandclarify terminology.WerecallPalmerandFebria(2012)toshowthelink- agesthroughthecascadechain:thecomponentsofanecosystem (thatrepresentthestructure)interactwithdynamicbiophysical processes(thatarefunctions)toproducegoodsandservicesthat peoplerelyon.Weargue thatecosystemservicesshouldexclu- sively beconsideredas theinteractions of theecosystemsthat producea changeinhumanwell-being (Table 2).Wetherefore proposethatecosystemservicesarenotindividualecosystemcom- ponents or goods.In addition,while allecosystem servicesare derived fromecologicalprocesses(orsocio-ecologicalprocesses Mononenetal.,2016)notallprocessesproduceecosystemser- vices.Someprocessesmaynotbeofusetohumans,butthisdoes notnegate theirimportance.Ecosystemfunctionandecological processesareconsideredhereassynonyms.

Duetotheutilitarian natureofecosystem services,research and policytend toemphasize end-use benefitsrather than the underpinningecosystemstructuresandprocesses(see‘Traditional understanding of the cascade framework’ in Fig. 4). We pro- poseamodified cascadeframeworktoshiftperspectivetoward ecosystems(see‘systemsecologyre-interpretationofthecascade framework’inFig.4).InFig.4werepresenttheflowfromaneco- logicalperspective.Theelementsofthecascadearenot‘equal’.Itis thusnotenoughtoestablishacausalsequenceamongtheelements ofthecascadebecausetheinherentcomplexityofeachstagemust behighlighted.

Toacknowledgethiscomplexity,thehierarchicalorganization isacrucialconceptinsystemsecology.Hierarchicallevelsinclude atoms,cells,organs,species,populations,ecosystems,landscape, regionsandtheecosphere(Jørgensen,2012).Eachlevelintegrates thefunctionsofthelowerlevel.⁵Whenweconsiderthehierarchy fromaverticalperspective,eachlevelisconstrainedfromtheupper levelandfromthelowerlevel.However,thereisalsoahorizontal perspective.Thereiscooperationamongthecomponents,which createsnetworks,whereinteractionstakeplace.

Inmanyrepresentationsofthecascadeframeworknaturalcap- italisconsideredasexamplesof beneﬁts(reported asassetsor commoditiesdependingonthedegreeofhumaninterventionin theproductionprocess).Naturalcapital,suchasﬁberandfood,are biomass.Fromavertical(hierarchical)perspectivethesecompo- nentsrepresentalowerlevel,whilepopulationsoforganismsarea higherlevel.Populationsinturnrepresentsalowerlevelcompared totheecosystem.Differentlevelsinteractbetweeneachotherverti- cally.Inaddition,interactionsamongbioticandabioticcomponents existalsoathorizontallevel.Verticalandhorizontalinteractions constitutetheservice.

Based on the hierarchicalorganization drawn from systems ecology, it is possibleto highlight the differencebetween ser-

5Forexample:atcelllevelontheonehandtheintegratedcellprocessesdeter- minethefunctionalityoftheorgans,ontheotherhandorganscontroltheﬁnal biochemicalresultsofcells;atthelevelofpopulationsontheonehandtheindivid- ualsandtheirinteractionsdeterminethepropertiesofthepopulations,andonthe otherhandpopulationdeterminesthelivingframeworkfortheindividuals.

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Table2

Proposeddeﬁnitionsofthecascadeframeworkterminology.

Term Deﬁnition Examples^a

Biophysicalstructure^b Thesettingforecosystemcomponents(bioticandabiotic).

Thisalsorelatestotheecologicalpattern

Foresttreecover Inlandwaterbodies Processorfunction Anecologicalinteractionamongcomponentsinan

ecosystemovertime.Processesmaygenerateseveral ecosystemservices.

Netprimaryproduction Carboncycling Nutrientcycling Ecosystemservice Aﬂowgeneratedbytheecosystemincludingecological

interactionsandinformationwhichareusefultohuman beings.Wethereforeproposethatecosystemservicesdo notincludeecosystemcomponentsorgoods,i.e.countable as(bio)massunit.Inaddition,ecosystemservices sometimesrequirehumaninput,whichdoesnot necessarilymeanhuman-madeconstructslikelabour, industrialprocessing,benchesorﬁshingroads.^a

Generationofmaterialfromplants Carbonsequestration

Waterpuriﬁcation

Aestheticbeautyoflandscape

Good Countableasa(bio)massunit,itisavehicleforecosystem serviceenjoyment.

Woodbiomass

AmountofCO2retainedfromtheatmosphere Amountofpollutantsretainedfromwaterbodies Peopleenjoyingoutdoorrecreationactivities Beneﬁt Whatisgeneratedbytheserviceandleadstoachangein

humanwell-being.

Availabilityofwoodformultipleuses

Healthierairtobreath/climatechangemitigation Availabilityofcleanerwater(insteadofwaterpollutedby economicactivities)

aExampleofhumaninputincludesexistenceofahumanbeingwithhis/hersensoryandperceptionalexperiences.

b Existingliteratureoftenusesthetermecologicalstructureasasynonymforbiophysicalstructure.Wehoweverpreferthelaterterm,becauseitalsoincludesnon-vegetated structures,suchasdunes,aquifersorRockyMountains.

viceandbenefits.Aserviceisaprocessandisdeterminedbythe horizontalandverticalnetworkingactivity.Benefitsareindivid- ualcomponents,countableas abiomass unit,and a vehiclefor ecosystemserviceenjoyment(Matthiesetal.,2016).Inthecurrent cascadeframework,greatemphasisisconvergingonthebenefit, becausethis ismostrelevanttohumans.Itisnotourintention todownplaytheimportanceofbenefits(andthusthe‘humans’

roleinco-producingecosystemservices).We,however,arguefor ashiftofperspectivefroma‘twodimensional’toa‘telescopic’cas- cadeframeworkwhichemphasizestheecologicaldimensionsand complexreality.

Theimplicationsofahierarchicalorganizationareinlinewith the understanding of ecosystems at the basis of the cascade framework:upperlevelschangemoreslowlythanlowerlevels.

Variationsanddisturbancesofupperlevelsmayaffectthelower levels;theotherwayround, however, isless frequent,because lowerleveldisturbancesaremitigatedatupperlevel(Jørgensen, 2012).⁶Forexample,assuminganinitialhealthystateoftheecosys- tem,whenasinglecomponentofthepopulationisremoved(e.g.

atreefromaforestoroneanimalfromapopulation),theregen- erationcapacityisnotaffected,thefunctioningoftheecosystem ismaintainedatahealthystate.Whenaclear-cuttakesplaceor thespeciesbecomerareorextinct,thentheentirehabitatwillbe affected(e.g.theforestwillnotbethereanymoreandthefoodchain willchange).

Anyassessmentandvaluationintendedtoprovideasustainable policyforthemediumandlongtermcannotignoretheecologi- calsystemsideofthecascade.Theexistenceofthesocialsystem isguaranteedbytheproperfunctioningoftheecologicalsystem.

Thevalueoftheecologicalsystemisintrinsic,andtheapproachis holistic,bio-centricandpositivist.Theecosystemservicesnarra- tiveispartofthehumansystemwhosevalueisutilitarian,andits approachreductionistandhuman-centered.

6 Amalfunctionofonelevelcanbeeliminatedbyreplacingafewcomponentson thelowerlevel.e.gcells,organsandspeciescanbereplacedtobetterﬁtthenew emergentconditions.Thus,thehigherthelevelis,thelessvulnerableitbecomes.

4.2. Comparingthereneweddeﬁnitionofecosystemservicesto CICESclassiﬁcation

Weproceedbycomparingtheconceptsintroducedfromsystem ecologytotheCICESclassificationandthecascadeframework.In Table3welistthecorrespondencebetweenCICESclassesandour terminology.Thisanalysisdoesnotintendtoaddanewlevelof complicationtotheecosystemservicesconceptualization.Rather itaimsatclarifyingthedifferencebetweenecosystemservicesand benefitsandtoimproveconsistencyintheclassificationofecosys- temservices.

AmongthelistofecosystemservicesproposedbyCICES,someof themdonotmeettherequirementsforourdefinitionofecosystem services(i.e.processes)(Table3).For example, allCICES provi- sioningservicesarebenefits(i.e.biomass).Provisioningservices includeforexamplecultivatedcrops.However,theecosystemser- viceisinfacttheprocesstogeneratecropsandplants,ratherthan thecropsandplantsthemselves.Theuseofthebenefitasaproxy fortheserviceisacommonpractice,butitmightresultindouble counting.Thus,theresultingbenefitfrome.g.regulatingservices shouldbearticulatedclearly,sothatoverlapswithprovisioning servicesare known.Forexample,benefitsfrompollinationmay overlapwithcultivatedcrops;waterflowmaintenancemayover- lapwithwatersupplied;ormaintainingnurserypopulationsand habitatsmayoverlapwithfood(fish)provisioning(Liqueteetal., 2016a).Whenperformingthetrade-offassessment,wedonotsug- gestignoringregulatingservices,butrathertocarefullyconsider betweenprovisioningandregulatingservices.

In CICES the list of services (in particular regulating services)sometimesincludesfunctionsandbiophysicalstructures.For instance,‘chemicalcondition’isapropertyorcomponentofthesys- temandnotaprocess.Itisthuspartofthebiophysicalstructure.

Theecologicalinteractionsamongcomponents,suchas‘hydrologicalcycle’and‘ventilationandtranspiration’areprocessesthattake placewithintheecosystem,andnottheﬂowofanindividualser- vicethatproducesadirectchangeinhumanwell-being.Differently frombeneﬁts,thebiophysicalstructurecannotbeaproxyforthe

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Table3

Classiﬁcationofecosystemservices(CICES)includingthenatureofecosystemservices,thecascadeframeworkstep,theSystemsEcologycategory,themostlogic/common assessmenttechniqueandtheirdegreeofcomplexity.

ListofecosystemservicesaccordingtoCICES Cascade frameworkstep

SystemsEcology category

Assessmenttechnique

Provisioning Cultivatedcrops Beneﬁt Biomass Statisticaldatasets

Wildplants,algaeandtheiroutputs Beneﬁt Biomass Statisticaldatasets

Wildanimalsandtheiroutputs Beneﬁt Biomass Statisticaldatasets

Plantsandalgaefromin-situaquaculture Beneﬁt Biomass Statisticaldatasets

Animalsfromin-situaquaculture Beneﬁt Biomass Statisticaldatasets

Materialsfromplants,algaeandanimalsfor agriculturaluse

Beneﬁt Biomass Statisticaldatasets

Geneticmaterialsfromallbiota Beneﬁt Biomass/information Statisticaldatasets

Rearedanimalsandtheiroutputs Beneﬁt Biomass Statisticaldatasets

Surfacewaterfordrinking Beneﬁt Biomass Statisticaldatasets

Groundwaterfordrinking Beneﬁt Biomass Statisticaldatasets

Fibersandothermaterialsfromplants,algae andanimalsfordirectuseorprocessing

Beneﬁt Biomass Statisticaldatasets

Surfacewaterfornon-drinkingpurposes Beneﬁt Mass Mainlystatisticaldatasets

Groundwaterfornon-drinkingpurposes Beneﬁt Mass Mainlystatisticaldatasets

Plant-basedresources Beneﬁt Biomass Statisticaldatasets

Animal-basedresources Beneﬁt Biomass Mainlystatisticaldatasets

Animal-basedenergy Beneﬁt Biomass Mainlystatisticaldatasets

Regulatingand maintenance

Bio-remediationbymicro-organisms,algae, plants,andanimals

Service Interaction Biophysicalmodelsand/or

measures Filtration/sequestration/storage/accumulation

bymicro-organisms,algae,plants,andanimals

measures Filtration/sequestration/storage/accumulation

byecosystems

measures

Mediationofsmell/noise/visualimpacts Service Interaction Biophysicalmodelsand/or measures

Dilutionbyatmosphere,freshwaterand marineecosystems

Function

Hydrologicalcycle Function

Waterﬂowmaintenance Service Interaction Biophysicalmodels

Massstabilizationandcontroloferosionrates Service Interaction Biophysicalmodels Globalclimateregulationbyreductionof

greenhousegasconcentrations

Service Interaction Biophysicalmodels

Microandregionalclimateregulation Service Interaction Biophysicalmodels

Bufferingandattenuationofmassﬂows Service Interaction Biophysicalmodelsand/or measures;Geospatialmodels

Floodprotection Service Interaction Biophysicalmodelsand/or

measures;Geospatialmodels

Stormprotection Service Interaction Biophysicalmodelsand/or

measures;Geospatialmodels

Pollinationandseeddispersal Service Interaction Biophysicalmodelsand/or

measures;Geospatialmodels Maintainingnurserypopulationsandhabitats Service Interaction Biophysicalmodelsand/or

measures;Complexindicators integratedwithgeospatialmodels

Pestanddiseasecontrol Service Interaction Biophysicalmodelsand/or

measures;Geospatialmodels Ventilationandtranspiration Function

Weatheringprocesses Function

Decompositionandﬁxingprocesses Function

Chemicalconditionoffreshwaters Biophysicalstructure Chemicalconditionofsaltwaters Biophysicalstructure Cultural Experientialuseofplants,animalsand

land-/seascapesindifferentenvironmental settings

Service Information Geospatialmodels/complex

indicators Physicaluseofland-/seascapesindifferent

environmentalsettings

Service Information Geospatialmodels/complex

indicators

Aesthetic Service Information Geospatialmodels/complex

indicators

Education Service Information Complexindicators

Heritage,cultural Service Information Complexindicators

Entertainment Service Information Complexindicators

Scientiﬁc Service Information Complexindicators

Symbolic Service Information Complexindicators

Sacredand/orreligious Service Information Complexindicators

Existence Value

Bequest Value

Theattemptistodevelopthesameexamplesthroughoutthe‘terminologychain’toshowthattheyareindeeddifferentstageofthesameprocess.E.g.todifferentiatethe carboncyclingasfunctionfromcarbonsequestrationasservicefromCO2tonswill(ifever)bethetaskofthebiophysicalmodel,i.e.onlyoneofthosestageswillbemapped andassessed,itwilldependonthetechniqueusedtoassess(modelorindicatororstatistics).

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Fig.4. Froma2Dtoatelescopiccascadeframework(a)Traditionalunderstandingofthecascadeframeworkwithemphasisonend-usebeneﬁts;(b)SystemsEcology re-interpretationofthecascadeframework,withemphasisontheunderpinningcomplexityoftheecologicalsystem.

service⁷:theyarewhatallowstheserviceﬂowtobegenerated(cf.

Mononenetal.,2016).InCICESexistenceandbequestvaluesare listedasservices:whenattemptingamonetaryvaluation,existence andbequestnon-usevaluesareconceptsthatfacilitatethechoice ofthevaluationtechniquetobeadopted,buttheyarenotthem- selvesecosystemservices.Systemsecologytheorycanthusprovide guidancefor ecosystemserviceassessments: Table3 presentsa newclassiﬁcationapproachfor ecosystemservicesassessments.

InTable3weattempttotrackcorrespondencewiththedifferent typologiesofmodelingtechniques.Byreferringtothesystemsecol- ogycategoriesofbiomass,interactionandinformationwecould statehowcomplexthelevelofmodelingshouldbe.

Whenecosystemservicesareidentiﬁedasbiomass,measure- mentwillrequirethecollectionofenvironmentalstatistics and inventories.Thisisthecaseformanyprovisioningservices,where

7 ThisisthereasonwhyinTable3whatcorrespondsto‘Biophysicalstructure’and

‘Function’isnotclassiﬁedintermsofSystemsEcologycategory,andAssessment techniquearethusreportedasgreycells.

data is usually extracted fromagriculture and forestry statisti- caldatabasesandinventories,orfrommarkettransactions,rather thanbiophysicalprocesses.Simpleandavailableindicatorscanbe used,suchasland-useandland-coverdata,biodiversitymonitor- ingmaps,ornationalforestinventories.Inthiscase,ratherthan assessingtheservice itself,thebeneﬁt is usedasproxy forthe ecosystemservice.Thisismostrelevanttoprovisioningservices andthecurrentpracticeofassessment.

Whenecosystemservicesareidentiﬁedasinteraction,theneco- logicalmodelingormonitoringisneeded.Tocorrectlyassessthe service,thenatureoftheprocessshouldbeunderstood,described analyticallyandmeasured.Thisisthecaseforsomeregulatingser- vices(i.e.allthoseservicesthatdirectlyinvolvebiogeochemical cycles)whereprocess-basedmodeling wouldbetterﬁtthepur- pose,becausethemodelshouldbeabletorepresent/replicatethe ecosystemfunctioning(e.g.Liqueteetal.,2016b).Thereare,however,casesinwhichspatialmodelingandstatisticalmodelingcould servetheassessmentpurpose.Inspatialmodelingalgorithmsbased onspatialfeaturesareusedand/ordifferentindicatorsarelinked withlandusedatatoderivemorecomplexindicators(seeforexam-