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Building blue infrastructure: Assessing the key environmental issues and priority areas for ecological engineering initiatives in Australia's metropolitan embayments

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Ecological engineering principles are increasingly being applied to develop multifunctional artificial structures or rehabilitated habitats in coastal areas. Ecological engineering initiatives are primarily driven by marine scientists and coastal managers, but often the views of key user groups, which can strongly influence the success of projects, are not considered. We used an online survey and participatory mapping exercise to investigate differences in priority goals, sites and attitudes towards ecological engineering between marine scientists and coastal managers as compared to other stakeholders. The surveys were conducted across three Australian cities that varied in their level of urbanisation and environmental pressures. We tested the hypotheses that, relative to other stakeholders, marine scientists and coastal managers will: 1) be more supportive of ecological engineering; 2) be more likely to agree that enhancement of biodiversity and remediation of pollution are key priorities for ecological engineering; and 3) identify different priority areas and infrastructure or degraded habitats for ecological engineering. We also tested the hypothesis that 4) perceptions of ecological engineering would vary among locations, due to environmental and socio-economic differences. In all three harbours, marine scientists and coastal managers were more supportive of ecological engineering than other users. There was also greater support for ecological engineering in Sydney and Melbourne than Hobart. Most people identified transport infrastructure, in busy transport hubs (i.e. Circular Quay in Sydney, the Port in Melbourne and the Waterfront in Hobart) as priorities for ecological engineering, irrespective of their stakeholder group or location. There were, however, significant differences among locations in what people perceive as the key priorities for ecological engineering (i.e. biodiversity in Sydney and Melbourne vs. pollution in Hobart). Greater consideration of these location-specific differences is essential for effective management of artificial structures and rehabilitated habitats in urban embayments.
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Researcharticle
Buildingblueinfrastructure:AssessingthekeyenvironmentalissuesandpriorityareasforecologicalengineeringinitiativesinAustralia'smetropolitan
embayments
E.M.A.Straina,b,c,
beth.strain@unimelb.edu.au
R.L.Morrisc
M.J.Bishopa,d
E.Tannera,e
P.Steinberga,b
S.E.Swearerc
C.MacLeodf
K.A.Alexanderf,g
aSydneyInstituteofMarineScience,19ChowderBayRd,Mosman,NSW,2088,Australia
bCentreforMarineBio-Innovation,SchoolofBiological,EarthandEnvironmentalSciences,UniversityofNewSouthWales,Sydney,NSW,2052,Australia
cNationalCentreforCoastsandClimateandSchoolofBioSciences,TheUniversityofMelbourne,Melbourne,VIC,3010,Australia
dDepartmentofBiologicalSciences,MacquarieUniversity,Sydney,NSW,2109,Australia
eSchoolofGeosciences,UniversityofSydney,Sydney,NSW,2006,Australia
fInstituteforMarineandAntarcticStudies,UniversityofTasmania,Hobart,TAS7001,Australia
gCentreforMarineSocioecology,UniversityofTasmania,Hobart,TAS7014,Australia
Correspondingauthor.SydneyInstituteofMarineScience,19ChowderBayRd,Mosman,NSW,2088,Australia.
Abstract
Ecologicalengineering principlesareincreasinglybeing appliedtodevelopmultifunctionalartificialstructuresorrehabilitatedhabitatsin coastalareas.Ecologicalengineeringinitiativesareprimarilydrivenbymarine
scientistsand coastalmanagers,butoften theviews ofkeyuser groups,whichcan stronglyinfluencethe success ofprojects,arenotconsidered.Weusedanonline surveyandparticipatorymapping exercisetoinvestigate
differencesinprioritygoals,sitesandattitudestowardsecologicalengineeringbetweenmarinescientists andcoastal managersas comparedto otherstakeholders.ThesurveyswereconductedacrossthreeAustralian cities
that varied in their level of urbanisati on and environmental pressures. We tested the hypotheses that, relative to other stakehold ers, marine scientists and coastal managers will: 1) be more sup portive of ecological
engineering; 2) be more likely to agr ee that enhancement of biodiversity and rem ediation of pollution are key priorities for eco logical engineering; and 3) identify different  priority areas and infrastructure or degrad ed
habitatsforecologicalengineering.Wealsotestedthehypothesisthat4)perceptionsofecologicalengineeringwouldvaryamonglocations,duetoenvironmentalandsocio-economicdifferences.Inallthreeharbours,marine
scientists and coastal managers we re more supportive of ecological engineering than oth er users. There was also greater supportsupport for eco logical engineering in Sydney and Melbourne than Hob art. Most people
identifiedtransport infrastructure,inbusytransporthubs(i.e.CircularQuayinSydney,thePortinMelbourneandtheWaterfrontin Hobart)asprioritiesfor ecologicalengineering,irrespective oftheir stakeholdergroupor
location. There were, however,significant differences among locationsin what people perceive as the key priorities for ecological engineering (i.e. biodiversity in Sydney and Melbourne vs. pollution in Hobart). Greater
1Introduction
Human population growth is accele rating and is forecast to reach 10 billion by 205 0 (Bloom,2011; Lutz and Sa mir, 2010). Muc h of the recent human population growth is in vulne rable coastal regions and this trend is
predictedtocontinue(Martínezetal.,2007;SmallandNicholls,2003).Currentestimates suggestthat>40%ofthe globalpopulationand60%ofitslargest cities(>5 millionpeople)are foundwithin100 kmofthecoast(Firth et al.,
2016).Coastalurbanisationhasbeen linkedwithextensivelossandfragmentationofnaturalhabitatsandspecies (McKinney,2008),theintroductionofpollutants, suchasheavymetals,nutrients,artificiallightand sound(Halpernet
al.,2008),andan increasing needforbuilt infrastructure (Daffornetal., 2015). Builtinfrastructureservesa diversity of purposes, suchascoastal defence (e.g. breakwaters, seawalls, groynes), transport orrecreation(e.g.marinas,
piers,ports),services(e.g.stormdrainsandcanals)orindustry(e.g.pipesandaquaculturecages),(Strainetal.,2018).
Builtinfrastructure impactsonnaturalecosystemsinavarietyofways,includinglossofnatural habitats(Heeryetal.,2017),andthemodificationofecologicalconnectivity (Bishopetal.,2017),ecosystemfunctioning(Mayer-
Pintoetal.,2015Mayer-Pintoetal. ,2018 (Mayer-Pintoetal.,2018) (Mayer-PintoM,Co leVJ,JohnstonEL,BugnotA,HurstH,Airoldi L,GlasbyTM,DaffornKA.Functionaland structuralresponsestomarineurbanisa tion.EnvironmentalResearchLetters.
2018Jan5;13(1):014009.))andservices(Airoldietal.,2015),aswellasthephysico-chemicalenvironment(Hinkeletal.,2014;KittingerandAyers,2010).Inresponse,thereis growinginterestin‘ecologicalengineering’,the application
ofecologicalprinciplesto mitigate the negative impacts ofbuiltinfrastructure(ChapmanandUnderwood,2011;FrancisandLorimer,2011;Mitsch,2012).Ecologicalengineeringapproaches include: (1)modifying theattributesof
neworexistingbuiltinfrastructurebyaddingstructuralcomplexity,buildingwithmoreeco-friendlymaterials,orseedingwithhabitat-formingorganisms(termed‘hard’ ecologicalengineering;ChapmanandUnderwood,2011,Firthet
al., 2016 Firth et al., 2014 (Firth et al., 20 14))(Firth LB, Thompson RC, Bohn K, Abbiati M, Airoldi L, Bouma TJ, Bozzeda F, Ceccherelli VU,Colang elo MA, Evans A, Ferrario F. Between a rock and a hard plac e: environmental and engineering
considerations when designing coasta l defence structures. Coastal Engineering . 2014 May 1;87:122-35.); (2) replacing built infrastructure withrestored or created habitats such as saltmarshes, mangroves or oyster reefs(‘soft’ecological
engineering;Temmerman,Meireetal.,2013;Morris,Konlechneretal.,2018);and(3)combining restoredor createdhabitatswithbuiltinfrastructure,forexampleplanted wetlandsbehindarocksill(‘hybrid’ecological engineering,
ChapmanandUnderwood,2011).Althoughthe ecologicalobjectivesandtypeofenvironmentwillinfluencethechoiceofapproach,theoverall objectiveisthesame:tobuildmulti-functionalinfrastructureorrestoredegradedhabitats
tothebenefitofbothhumansandnature(Mitsch,2012).
Ecologicalengineeringprojectsareoftendrivenbymarinescientistsandcoastalmanagers,however,marineprofessionalshavesignificantlydifferentperceptionsonenvironmentalissuescomparedtootherstakeholdergroups
(Easmanetal., 2018). Responsesofstakeholders to new policies or conservation projectscanvarydepending on a range of socio-economic factors,suchaseducation, occupation or income (Derkzen et al., 2017). The uptake, and
thereforethe success ofecologicalengineeringinitiativesis dependent ongainingbroadstakeholdersupportsupport(Gelcichet al.,2008).For example, anecologicalengineering projectdrivenbymarine scientists/coastalmanagers
that fails to get social licenceis unlikely to be implemented at multiple sites. Conversely, a project that proceeds without input from marine scientists andcoastal managers may lackthe expert knowledge required for successful
implementation.TheLivingBreakwatersproject, which couplescoastalprotectionwith habitat creation, andis to beimplementedon Staten Island,USAin 2020, hasgainedwidespreadsupportsupportfromthe local community asa
resultofits extensive consultationprocesswith marine scientistsand other user groups, and has stimulated interest in implementation of similar projects asfarawayasEurope(rebuildbydesign.org/our-work/all-proposals/winning-
projects/ny-living-breakwaters).Withinecologicalengineeringprojects however,thereis relativelylittleresearch onhow theperceptionsand prioritiesofmarine andcoastalmanagers differfromthose ofother stakeholders, orwhat
thefactorsarethatinfluencetheviewsofthedifferentstakeholdergroups(Evansetal.,2017;Grayetal.,2017;Kienkeretal.,2018;Morrisetal.,2016bMor risetal.,2016 (correcttoMorrisetal.,2016)).
Thelevel ofsupportsupportforecologicalengineeringcan also differ between geographic locations (Morris etal.,2016b (Correctto Morris et al., 2016);Morrisetal.,2016;Evanset al., 2017; Kienker et al., 2018). Forexample,
recentresearchin Australia,NewZealand andtheUK hasdemonstratedthatmost peoplesurveyedwereinterestedintheconceptofecologicalengineering(Morriset al.,2016b; Morris etal.,2016;Evansetal.,2017; Kienker et al.,
2018).However,residents from moremodifiedembayments(>50%of harbour covered byseawall),in Sydney and Aucklandweremoresupportiveof ecological engineering inthemarine environment than residents inlessmodified
embayments (<40% of harbourcovered by seawalls) in Hobart and Tauranga(Kienker et al., 2018). People in more urbanised locations could be moreinterested in the concept of ecological engineering becauseof greater public
exposurethrough mediaandresearch(Morris etal.,2016aMorrisetal .,2016 (CorrecttoMorris etal.,2016)),increased connectionwithitswaterways(Kienkeretal.,2018),or highersocio-economicstatus(Ambrosius andGilderbloom,
2015;Berengueret al., 2005). Alternatively, the views of residents from different locationscouldbeinfluencedbythepopulation density,citysizeand/or other environmental pressures (Madureiraet al., 2015, 2018). Interestingly,
Kienkeretal.(2018)showedthatmostpeopleagreedthatecologicalengineeringwasimportantforimprovingbiodiversity,nurseryhabitat,waterquality,stabilisingtheshoreline,limitingdamagetoexistinghabitatsandreducingthe
abundancesof invasivespecies,irrespective oftheir locationorstakeholder group.However,Kienkeretal.(2018) didnotdetermine whether therewereany differencesamongstakeholdergroups orlocations,in theirperceptionsof
considerationoftheselocation-specificdifferencesisessentialforeffectivemanagementofartificialstructuresandrehabilitatedhabitatsinurbanembayments.
Keywords:Marineurbandevelopment;Eco-engineering;Spatialplanning;Artificialstructures;Coastalandmarinehabitats
thekeyenvironmentalissuesthatcouldbeaddressedusingecologicalengineering.
Participatorymapping is an approach that canbe used to represent the spatial knowledge of local communities (Sletto et al., 2009). It is usedin land- and sea-scape planningas well as conservation and natural resource
management (Sletto et al., 2009). Participatory mapping h as been applied to conservation in a wide range o f contexts including incorporation of local knowl edge (Aswani and Lauer,2006) , identifying conflicts between use and
conservation(Alexanderetal.,2012)andidentifyingcommunityvaluesandaspirations(BrownandWeber,2012;KlainandChan,2012;Raymondet al.,2009).Studieshavealsousedparticipatorymapping toidentifypriorityareasfor
terrestrialgreeningprogramsinurbancities(DeRidderetal.,2004;Tyrväinenetal.,2007;VandenBerg etal.,2007).Todate, however,nostudies haveused thistechniqueto identifythepriority sitesfordifferent stakeholders and
locationsinvolvedinmarineecologicalengineeringprojects.Thisinformationisimportantforensuringthesuccessofanyfutureecologicalengineeringinitiatives.
Inthisstudyweusedanonlinesurveyandparticipatorymappingexerciseto:(1)examinedifferencesintheperceptionsofmarinescientists/coastalmanagers,versusotherstakeholderstowardsmarineecologicalengineering;
and(2) identify anydifferencesinthe objectives and sitesforecologicalengineeringthesetwo groups would liketo see prioritised. The studywasreplicatedacross three Australian metropolitan embayments (Sydney Harbour,Port
PhillipBayandtheDerwentEstuary)thathavedifferentlevelsofmodification bybuiltinfrastructureandotherenvironmentalpressures (TableS1).Wehypothesizedthat comparedtootherstakeholders,marine scientistsandcoastal
managers would be more suppor tive of ecological engineering, be more likel y to consider biodiversity and remediation o f pollution as key issues for ecological engin eering, and identify different priority areas  and structures for
ecologicalengineering.Wealso predicted thatperceptionsandpriorities for ecologicalengineeringwoulddifferbetween thethreelocationsbecause of differencesinurbanisation,environmentalpressuresand othersocio-economic
factors. We discuss how the information provided by differe nt stakeholder groups through such participatory exercis es might be integrated in to environmental decision making . We then use the inform ation generated by this
participatorymappingexercisetoidentifypotentialecologicalengineeringoptionsforeachofthelocations.
2Methods
2.1Studysites
ThesurveywasundertakeninthreeAustraliancities(Sydney,MelbourneandHobart),eachofwhichissituatedonamajorestuaryorembayment.Thesecitiesdifferintheirphysicalandhumanpopulationsize,theirhistoryof
harbourdevelopmentanduse,presentdayindustry,theenvironmentalpressurestheyexertonestuarine ecosystems,aswellastheir populationdemographics(TableS1).Thesurveysweredistributedtorespondentslivingin,working
inorvisitingareaswithintwokilometresoftheforeshoretotargetpeoplewhoactivelyuseditswaterways(Kienkeretal.,2018).
2.2Studydesign
Thisstudyusednon-probabilisticsampling,includingpurposivesamplingformarinescientistsandcoastalmanagersandconveniencesamplingforotherstakeholderswhoareeasiertoreach(Blairetal.,2013).Anonline survey
andamappingexercisewereopentothepublicforfivemonthsbetween25Mayand22December2017.Wechosetouseaninternet-basedsurveyandmappingtooltoreachasbroadanaudienceaspossible.Allparticipantsanswered
thequestionsthroughSurveyMonkey(www.surveymonkey.com)andenteredthespatialdatadirectlyintothemappingtoolMaptionnaire(maptionnaire.com/).Participantswererecruitedthroughadvertisementsoncommunityboards,
businesscards,emails, socialmedia,newsletters,mailing lists,andin-personusing face-to-face surveysin four suburbs(twolower socioeconomic andtwohigher socio-economic suburbs) alongeachharbour foreshore (Kienker etal.,
2018).Specificusergroups (i.e.harbourmanagersandmarine scientists)werefurthertargetedthroughdirectemailsandface-to-facesurveysatmeetings,and socialevents (Kienkeret al.,2018). Allrespondentswere provided witha
participantinformationsheet(ethicsapprovalreferencenumber
H16175)
beforeagreeingtoundertakethesurvey(Fig.S2).
Theparticipantswereshownexamplesofecologicalengineeringinitiatives(Fig.S3),andasked iftheyweresupportiveoftheconcept(yesorno).Theyindicated whethertheywereamarinescientistor acoastalmanager(yes
or no) and then added point marker s indicating specific locations in which they  would like ecological engineering to be appl ied to online maps of Sydney Harbour (Sydn ey), PortPh illip Bay (Melbourne), or the Derwent Estua ry
(Hobart).Theparticipantscouldplacemultiplemarkers. Foreach point, they were asked to name thearea,thetypeof structure or degraded habitat (e.g. beaches, oyster reefs, mangrovessaltmarshes,seeTable S4forfulllist), to
which ecological engineering shou ld be applied. For each m arker, participants were asked to provi de reasons as to why they would like ecological engineering to occur th ere. The phrases enhancement of biodiversity and
remediationofpollution were provided to participantstoexplore any differences in perceptionbetween key stakeholders. However,the question was left open-ended tocapture further insights and complexityofresponses from
participants.
2.3Dataanalysis
Participantsidentified36 differenttypesofstructureordegradedhabitatsastargetsforecologicalengineering,which wereclassifiedintosix categories(transport,industry,coastaldefence, service,degradedhabitatorreef)
forthe purposesof the analyses (TableS4). Using generalisedlinearmodels,wetestedfor effects of stakeholder type (marine scientistsand coastalmanagersvsothers)on: supportsupportforecological engineering (yes or no), the
typesofstructuresidentifiedassitesforecologicalengineering (transport, industry,coastal defence, service, degraded habitat or reef), and the purpose of ecological engineering as enhancing biodiversity (yes or no) or mitigating
pollution/remediation of water quality (yes or no). These effects were compared across the three locations (Sydney,Melbourne and Hobart,fixedfactor=3levels).For all analyses, we tested and found no effects of over-dispersion
usingtheAERlibrary.AllanalyseswereconductedinR(www.R-project.org).
Wecross-checkedthatthe locationsnamedbyparticipantsastargets forecological engineeringwereconsistentwiththelocation ofpointstheyhadplacedonthe maps.Where therewereinconsistenciesthepointwas moved
tothecentreofthelocationgivenbyname.Thesenamedpoints,aswellasthosethatwereun-namedweremarkedandusedtoproduceheatmaps.Pointdataaddedtothemapsbythepublichavebeenshowntoaccumulatebetween
3and6km,soacircularsearchradiusandfixeddistancebandof5kmwere usedfortheanalysesinthispaper.Kerneldensitiesareinfluencedbythenumberofpointsadded,sodensityanalyseswerestandardisedbysubtractingthe
meangriddensityanddividingbythegridstandarddeviation.Kerneldensitieswereplottedin5natural(jenks)breaksintervalbandsforthehotspotheatmaps.AllanalyseswereperformedinArcGIS10.2(ESRI,RedlandsCA,USA).
3Results
3.1Respondents
Intotal,606peoplecompletedthesurvey(217inSydney,157inMelbourneand232inHobart)and421peoplecompletedthemappingexercise(153inSydney,100inMelbourneandin168Hobart).Thisnumberofresponses
iscomparabletoother,similar,publicperceptionstudies(Evansetal.,2017;Morrisetal.,2016bM orrisetal.,2016 (CorrecttoMorrisetal.,2016)).
3.2SupportSupportforecologicalengineering
Thesurveyindicatedmostrespondents(>70%)supportedsupportedecologicalengineering.Inallthreelocations,marinescientistsandcoastal managerswere,however,moresupportiveoftheconceptofecologicalengineering
thanpeopleintheotherusergroups(Fig.1,Table1).TherewasalsogreatersupportsupportforecologicalengineeringinSydneyandMelbournethanHobart(Fig.1,Table1).
Table1Resultsofgeneralisedlinearmodellingtestingfordifferencesbetweenstakeholdergroups(marinescientists/managersvsothers)andlocations(SydneyvsMelbournevsHobart)inparticipantsupportfor
ecologicalengineering(yes/no).Significantp-values(<0.05)areindicatedinbold-print.
alt-text:Table1
Factor df Deviance Residualdf ResidualDeviance P-value
Null 606 295.75
Location 3 544.35 603 295.75 <0.001
Stakeholder 1 8.16 602 287.58 0.005
Fig.1Percentageofmarinescientists/coastalmanag ersandotherusersthatsupportedecol ogicalengineeringofbuiltstructuresor degradedhabitatsina)Sydney,b)Melbourneandc)Hobart.
alt-text:Fig.1
3.3Keylocationsidentifiedforecologicalengineering
Theareas mostfrequentlyidentifiedbythe789 pointsassitesforecologicalengineering werecentraltransporthubs. Thispatternwasseenacross allrespondents,aswellasfor marinescientists/managers.Thesetransport
hubsincluded Circular QuayinSydney (whichaccountedfor 18.6% ofall marked points,and33.33% ofpointsfrom marinescientists/managers), thePort ofMelbournein Melbourne(10.86%of allmarkedpoints;24.12% formarine
scientists/managers) and the WaterfrontinHobart (20.71% of all marked points; 37.25% for marinescientists/managers (Fig. 2, TableS5). The other areasof interest for the participantswere Blackwattle Bay (9.75% ofallmarked
points)inSydney,StKildabeach(9.14%ofallmarkedpoints)inMelbourneandtheZincworks(7.77%ofallmarkedpoints)inHobart,(Fig.2,TableS5).
3.4Priorityinfrastructureidentifiedforecologicalengineering
Thepointdata showedthattransportinfrastructure(jetties,terminals,ferry,piers,wharves,marinas, docks,ports,shipyardsandyachtclubs)wasconsistentlyidentifiedbymarinescientists/coastal managersandotherusers,
inallthreelocations,astheprioritystructuresforecologicalengineering(Fig.3,Table2).ThiswasfollowedbycoastaldefenceinfrastructureinSydneyandHobartanddegradedhabitatsinMelbourne.
Fig.2Heapmapsshowingprioritysite sidentifiedbymarinescientists/coastalm anagersandotherusersforecological engineeringofartificialstructuresorreh abilitatedhabitatsina)SydneyHarbou r,b)PortPhillipBayandc)DerwentEstuary.Reddotsarepointsfrommarine
scientists/coastalmanagers.Numbered pointsonthemapcorrespondtothena mesinTableS5.(Forinterpretationofthereferencestocolourinthisfigureleg end,thereaderisreferredtotheWebversionofthisarticle.)
alt-text:Fig.2
Table2Resultsofgeneralisedlinearmodellingtestingfordifferencesbetweenstakeholdergroups(marinescientists/managersvsothers)andlocations(Sydneyvs.Melbournevs.Hobart)inthetypesofbuilt
structures/degradedhabitats(transport,vs.coastalvs.industrialvs.reefsvs.degradedhabitats,vs.services)identifiedforecologicalengineering.Significantp-values(<0.05)areindicatedinbold-print.
alt-text:Table2
Factor df Deviance Residualdf ResidualDeviance P-value
Null 662 2503.37
Location 3 1822.84 659 690.53 <0.001
Stakeholder 1 1.94 658 678.59 >0.05
3.5Environmentalprioritiesforecologicalengineering
Thepointdataalsoindicated that the priorities for ecological engineeringdifferedbetween locations but not users (Fig. 4, Table3). In both Sydney and Melbourne, all the participants identified that increasing biodiversity
shouldbethepriorityforecologicalengineering,whereasinHobartmorepeoplewantedtoreducepollutionorincreasewaterquality(Fig.4,Table3)(seeFig.5 (Incorrectcitation)).
Fig.3Thedominantartificialstructures ordegradedhabitatsforecologicaleng ineeringidentifiedbyparticipantsina)S ydney,b)Melbourneandc)Hobart.
alt-text:Fig.3
Fig.4Wordcloudshowingtheparticipantsprioritiesforeco logicalengineeringina)Sydney,b)Melbourneandc)Hobart.
alt-text:Fig.4
Table3Resultsofgeneralisedlinearmodelstestingfordifferencesbetweenstakeholdergroups(marinescientists/managersvsothers)andlocations(SydneyvsMelbournevsHobart)inconsiderationof
enhancementofbiodiversity(yes/no)andremediationofpollutionorincreasewaterquality(yes/no)askeyprioritiesforecologicalengineering.Significantp-values(<0.05)areindicatedinbold-print.
alt-text:Table3
Factor Df Deviance Residualdf ResidualDeviance P-value
Biodiversity
Null 730 1011.99
Location 3 343.67 727 668.32 <0.001
Stakeholder 1 1.13 726 677.19 >0.05
Pollution
Null 730 1011.99
Location 3 185.14 727 826.86 <0.001
Stakeholder 1 1.15 726 814.71 >0.05
4Discussion
4.1Perceptions,keyenvironmentalissuesandsitesidentifiedbystakeholdersforecologicalengineering
Thereisincreasinginterestin combiningscientificknowledgeandpublicperceptionsto guide urban greening or ecological engineering initiativesin both terrestrial and marine environments (Goddard et al., 2010; Janse and
Konijnendijk,2007;RocaandVillares, 2008;Warrenetal.,2005). Weprovide the firstempiricalevidence,thatdespitethe differences in prior knowledge between stakeholder groups whose professions areactivelyengagedinecological
engineering (i.e. marine scientists  and coastal managers) and those that are not, both groups identifie d the same priority infrastructure, environmental issues and loca tions for ecological engineering initiatives in the marine
environment.Foreachofthree Australian embayments surveyed, mostpeople(>70%) were supportive ofecologicalengineering,however,supportsupportwas positively influenced bypriorknowledgeand differed between locations,
consistentwithotherstudies(Evansetal.,2017;Kienkeretal.,2018).Similarly,acrossthethreelocations,bothgroupsidentifiedtransportinfrastructure(jetties,wharves,marinas,piersandyachtclubs,quays)asthehighestpriorityfor
Fig.5Ecologicalengineeringsolutions proposedforSydneyHarbour,PortPhillipBayandtheDerwentEstuarya)hardso lutionsfortransportandcoastalinfrast ructureinexposedandmodifiedsites,b )hybridsolutionsforcoastalinfrastructu reinmoderatelyexposedandmodified
sitesandc)softsolutionsfordegradedh abitatsforshelteredandlessmodifiedsites. (MoveFig.5under Table4)
alt-text:Fig.5
ecological engineering. This was c losely followed by coastal infrastructure (seawalls, groynes a nd breakwaters) in Sydney and Hobart and degraded habitats  (beaches, saltmarshes, mangroves, seagrasses and oyster r eefs) in
Melbourne.Thisconsensusisvitalforpreventingthefailureofecologicalengineeringproject(Lietal.,2012).
Incontrast, across all three locations, therewere distinct differences in the environmental issues defined by respondentsaskeyobjectives for ecological engineeringinitiatives in the marine environment.Enhancement of
biodiversitywasa greaterpriorityfor peopleinSydney andMelbournethanHobart, where respondents expressedstrongerconcernfor pollutionremediationorincreasingwater quality.Thesetrends coulddemonstratestronglinks
betweenthepeoplesurveyedandtheirknowledge oftheir environment(WalmsleyandLewis,2014). Forexample,studiesinsouth-easternAustraliahavedemonstratedthattransportinfrastructureisassociatedwithsignificantlylower
biodiversity relative to other infras tructure, because of heavy metal and bioci de run-off from the anti-fouling paint couple d with elevated sediment and turbidity leve ls (Dafforn et al., 2012;Fowles et al., 2018). Similarly,survey s of
pollutionlevelshaveshownthatdespitetheirsimilaritiesinindustryanddevelopment,theDerwentEstuaryhadmuchhigherlevels(>10timetheconcentrations)ofheavymetalsinsedimentthaneitherSydneyHarbourorPortPhillip
Bay(Lingetal.,2018).Alternatively,theviewsofresidentsfromdifferentlocationscouldbeinfluencedbytheirexposuretotheconceptsorothersocio-economicfactors(Madureiraetal.,2015,2018).
Inthisstudy,wecombined twotypesofnon-probability sampling purposiveandconvenience, toprovide crucialinsightsintohowdifferentstakeholdergroupsviewecologicalengineering,acrossthreelocations. Thistype of
samplingcanprovidevaluableinformationforearlystagesofdecision-making,raisingawarenessofthemarineenvironment,andidentifyingkeystakeholderperspectives(BrownandKyttä,2014;Jarvisetal.,2015) however,therecanbe
some problems in gettinga representative sample (Blair et al., 2013). To address these potential limitations, within each harbour location, we sa mpled respondents in a variety of places in cluding foreshore areas, street locations,
shoppingmallsandprivatebusinesses.Inallthreelocations,wealso sampledacrossfourareas withdifferent socio-economicstatus(Kienkeretal.,2018). Overall,we suggestthisapproachallowedustocaptureimportantinformation
aboutthekeyprioritiesandlocationsforfutureecologicalengineeringprojectsinSydney,MelbourneandHobart.
4.2Integrationofparticipatoryplanningintoecologicalengineeringprojects
Weproposethatthemethodsusedinthisstudycouldguidebestpractiseforplanningandmanagingfutureecologicalengineeringinitiatives.Theseprojectsshouldconsiderthegoalsandviewsofthemainstakeholdergroups
suchasmarinescientists/coastalmanagersandotherprivateandpublicusers(Yepsenetal.,2016).Manyframeworksandmethodsforparticipatoryplanninghavebeendevelopedwhichmayassistwiththis,forexamplefor,tidalenergy
arrays(Alexanderetal.,2012),marineprotectedareas(BrownandWeber,2011;Jarvisetal.,2015)terrestrialgreenroofs(JanseandKonijnendijk,2007),tonameafewexamples.However,todate,thesehaverarelybeenappliedtoecological
engineeringprojects.Inthefollowing sectionweshow howthepriority objectivesandsites identifiedthroughparticipatorymapping mightbeusedtodevelop ecologicalengineeringoptionsfor threeAustralianembayments,Sydney
Harbour,PortPhillipBayandtheDerwentEstuary.
4.3EcologicalengineeringoptionsforthethreeAustralianestuaries
In Sydney Harbour,the key  areas of interest for ecological engineerin g to enhance the native biodiversity were Cir cular Quay and Blackwattle Bay (Fig. 5, Table 4 (Fig.5 , Table4)). In both locati ons, the positive effects of
ecologicalengineeringinterventions biodiversityneedtobe temperedbypotentiallynegativeeffects ofthe interventionsonthelongevityoftheinfrastructureandonusers(Fig.5, (Fig. 5,Table4)Table4).Boating infrastructureblocks
lightwhichcan negativelyaffectthegrowthandsurvivorship ofprimaryproducerssuchasmacroalgaeandseagrasses,andmayinsteadfavourthe colonisationof non-nativemarineinvertebrates(ConnellandGlasby,1999;Marzinelli et
al.,2011).Thehard ecologicalengineeringinterventionswhichcouldbeappliedtoboatinginfrastructureincludetheadditionofLEDlights whichpromoteseaweedgrowthinaquaculturepractices,andprevent invertebratefoulingon
ships(Rabbette,1992), or skylights fins andotherenhancementsaddedtoseawallsto provide habitat for fishandinvertebrates(Munsch etal.,2017) and/or the incorporation of soft rope structure to create fishhabitat(HairandBell,
1992).Atthesesitesthebiodiversityonnearbycoastalinfrastructurecanalsobeenhancedbyretrofittingtileswithcreviceandridges(Strainetal.,2018)andflowerpots(whichserveassurrogaterock-pools;Browne&Chapman2014).
Interventionsoncoastalinfrastructurealsohastheadvantagethat,ifplacedintheintertidal,theywillbevisiblefromtheshoreline,creatingpublicinterest.
Table4Ecologicalengineeringsolutionsproposedbymarinescientiststoaddressenvironmentalissuesin,SydneyHarbour,PortPhillipBayandDerwentEstuary.
alt-text:Table4
Site Environmentalpriority Additional
Issues Infrastructure Solution
CircularQuay,SydneyHarbour Biodiversity Publicaccess,safety,exposure
Jetties/Wharves
Pontoons
Seawalls
LEDlights,skylightssoft
Crevice/Ridges,Flowerpots
Biodiversity NA Jetties/Wharves
Pontoons Skylights
BlackwatttleBay,SydneyHarbour Degradedhabitat Mangroves/Saltmarshhybrid
Oysterreef
Seawall Crevices/Ridges,Flowerpots
PortofMelbourne,PortPhillipBay Biodiversity Shipping Piers,Wharves,Pontoon Seedingwithbivalves
StKilda,PortPhillipBay Biodiversity Publicaccess
Piers
Seawalls,Breakwaters
Degradedhabitats
Seedingwithnativeorganismsor
Addingmicrohabitats,Seedingandplanting
Oysterormusselreefs
Waterfront,DerwentEstuary (Extensiveformattingissues.Redo)
Zincworks,DerwentEstuary
Pollution
Pollution
Publicaccess,exposure
Shipping,exposure
Piers,wharves,pontoons,
Seawalls
Piers,wharves,pontoons,
Seawalls
Seedingandplanting
Seedingandplanting
Seedingandplanting
InPortPhillipBay,theareathatreceivedmostinterestasasiteforecologicalengineeringwasatransportationhub,thewerethePortofMelbourne,withbiodiversityenhancementandwaterqualityimprovementidentifiedas
key goals (Fig. 5, Table4)(Fig. 5, Table4). The Port of Melbou rne is the largest container and general car go port in Australasia, therefore any ecolo gical engineering solutions must be sensi tive to maintaining these extensive port
operations.Shippingactivities inPortPhillipBayhave causedconsiderableecologicalimpacts,including theintroductionof >100invasivespeciesthrough transportoforganismsonhullsand inballastwater (Hewitt etal., 1999),the
spreadof which could thenbeexacerbatedbythe extensive artificial structures along theportshoreline(Airoldi etal.,2015). Ecological engineeringstrategiesthatenhancenative organisms,whileexcludinginvasivespecies,would
therefore be beneficial forthe local biodiversity (Dafforn et al., 2012). A promising har d ecological engineering approach cou ld be the seeding of structures with muss els (
Mytilusgalloprovincialis
), a native habitat-forming organism
(Paalvastetal.,2012;Strainetal.,2018).Musselbedscreatefoodandshelterfornumerousothermarineorganisms,whiletakingupspacethatcouldotherwisebecolonisedbynon-nativespecies(Coenetal.,2007).Further,musselscan
improvewaterqualitythroughthefiltrationoflargevolumesofwaterandsuspendedparticles(Denisetal.,1999).
Theother area that received highinterest for ecological engineering interventions in Port Phillip Bay wasthe foreshore of St Kilda,which contains both transportand coastal infrastructure (Fi g. 5, Table4 (Fig. 5, Table 4)).
DespitetheirconcernsStKildabreakwaterisawildlifemanagementcooperativeareaduearesidentcolonyoflittlepenguins.Volunteershavebeengreeningthebreakwatersinceitwasrefurbishedthroughre-plantingvegetationto
providesuitablehabitattosustainthepenguincolony(earthcarestkilda.org.au).Furtherbenefitscouldalsobeprovidedbyintegratingnativeorganismsand/orincreasinghabitatcomplexitythroughaddingmicrohabitats(Chapmanand
Underwood, 2011;Strainet al., 2018). Melbournediffered from Sydney and Hobartinthatdegraded habitats were identifiedas a high priority for ecological engineering (Fig. 3). At this site, the rehabilitation ofshellfish reefs could
providewaveattenuationandshorelinestabilisation,whiledeliveringotherecosystemserviceco-benefits(Scyphersetal.,2011).
Inthe Derwent Estuary,the keyareaswhererespondentsfeltecologicalengineeringwouldbe most beneficial were for improvement of waterqualityandreductionof pollution at the Waterfrontand near theZincWorks at
Lutana(Fig.5,Table4 (Fig.5,Table4)).Intheseareas,hard ecologicalengineeringsolutionsthroughseedingwith nativemusselsoroysters(McCayetal.,2003),andtransplantingseaweeds(Fariaset al.,2017) couldbeused toincrease
filtration capacity and nutrient uptak e to improve water quality around some transport infrastructure (e.g . pilings, pontoons and wharves) and coastal defence infrastructure ( i.e. seawalls). It is important that any ecological
engineeringinterventionsdonotenhancetheabundancesofinvasivespeciessuchasthepredatorJapaneseseastar(
Asteriasamurensis
)whichconsumesbivalves(LockhartandRitz,2001).
Themain concern, however atbothsites intheDerwentEstuary is heavymetalpollution,particularlyzinc, lead, cadmium(DerwentEstuaryProgram, 2016), whichaccumulateinthe sediment but are remobilised inthewater
columnthrough resuspension fromboatwakeandwaves. Therearelimited ecologicalengineeringoptionsfordealingwith heavymetalcontamination.Species thattake metalsoutofthesystem (e.g.bivalves,seaweeds, saltmarshes
and wetlands) are likely to bio-accumulate and/or bio-magnifythe pollutant. The only wayto remove the contaminantswould be to harvest the species, which may be counterproductive for biodiversity endpoints. Forspecies that
remaininthesystem,managementwould needtobecertainthatanyattempttoremovecontaminants throughenhancementofnativespeciesdoesnotinadvertentlyreintroducetheminto thefood chain.Iftheaimistoreduceheavy
metalcontamination,thenecologicalengineeringstrategiesfortheDerwentEstuarywillbenefitfromfacilitatingtheproductionoffastgrowingspecies,withlowpalatability,thatcanberemovedfromthesystemwithoutimpactingon
thebiodiversity(Fariasetal.,2017).
5Conclusion
Understandingtheattitudes,perceptions andvaluesofkeystakeholdergroupstourbanconservationinitiativesisvitalfordevelopingholisticmanagementstrategies.Wefoundthataclearmajorityofbothstakeholdergroups
(marinescientists/coastalmanagersvs.others)at allthreelocations weresupportiveof ecologicalengineering.Bothgroups similarlyidentifiedinterventionsthat targetenhancementof biodiversityormitigation ofpollutantsaround
transportinfrastructure as akeypriorityforecological engineering, creating a strong supportsupport base with which to moveforwardinthedevelopment of potential interventions. The ecologicalengineering options identified by
marinescientistsforthesehigh waveenergyand heavilymodifiedlocations includehardoptionsthatalterabiotic andbioticconditions toenhancebiodiversity,andseeding ortransplantingnativehabitat-formingspecies toenhance
biodiversityandimprove water quality (Table5).The costs of these interventions, is relatively low,rangingbetweenAUD$50to300 per m2 (Table5), particularly when compared with built infrastructure (Morris, Konlechner et al.
2018).However,further investmentwouldbe requiredformonitoringto ensurethe ecological engineering interventionshavethe desiredbenefits.Ecologicalengineeringprojects thatincorporatingthe viewsofmultiple stakeholder
groupscanprovidepeoplewithgreaterpublicaccesstothemarineenvironment,increasetourismandculturalactivities,andareimportantforscientificresearchandeducation(Yepsenetal.,2016).
Table5CostandbenefitsofcurrentecologicalengineeringsolutionsappliedinSydneyHarbour,PortPhillipBayandDerwentEstuary.
alt-text:Table5
Ecologicalengineeringoption Cost(AU$;perm2) Benefit Infrastructure Location Reference
Tilewithcrevicesandridges $150 Biodiversity Coastaldefence SydneyHarbour Strainetal.(2018)
Flowerpots $300 Biodiversity Coastaldefence SydneyHarbour Browne&Chapman(2014)
Softropestructure Unknown Biodiversity Transport SydneyHarbour HairandBell(1992)
Integratingmusselsontopilings $120 Unknown Transport PlannedtrialforPortPhillipBay Notyettrialled
Seedingmusselsonartificialreefs $50(notincludingcostsofartificialreef) Unknown Coastaldefence PlannedtrialforPortPhillipBay Notyettrialled
Transplantingmussels/oysters $50 Improvedwaterquality Coastaldefence/Transport DerwentEstuary NA
Transplantingseaweeds Unknown Improvedwaterquality Coastaldefence/Transport DerwentEstuary Notyettrialled
Ethics
Thiswork complied with the National Statement on EthicalConduct in Human Research (2007). The study wasapproved by the Human Research Ethics CommitteeattheUniversity of New South Walesunder application
referenceH16175.
Acknowledgments
WethanktheTheIanPotter Foundation(grantgrant number NA), HardingMillerFoundation (grantgrant numberNA),TheNew South Wales Government Office of Science and Research(grantgrant number NA) an d
ResearchCoastalProcesses andResponsesNodeoftheNSWOfficeofEnvironment andHeritage Adaptation Hub (grantgrant number NA) for theirfinancialsupportfinancial support. Special thanks to Sarah Kienker,Chris
Seito,DominicMcAfeeandStephanieBagalafortheirhelpwiththefieldwork.ThisstudywaspartoftheWorldHarbourProject.
AppendixA.Supplementarydata
Supplementarydatatothisarticlecanbefoundonlineathttps://doi.org/10.1016/j.jenvman.2018.09.047.
Uncitedreference
VictorianStateGovernmentandEnvironment,2017.(Delete)
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AppendixA.Supplementarydata
ThefollowingistheSupplementarydatatothisarticle:
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Highlights
QueriesandAnswers
Query:Ofthetwosetofauthorgroupwithaffiliationswereprovided.Hence,weusedtheauthorgroupwithaffiliationsprovidedalongwith“Mapping_RevisedPDSMJB2RMKASS_spl_KAagain
_spl_MBagain”.Pleasecheck,andcorrectifnecessary.
Answer:Correct
Query:Pleasecheckwhetherthedesignatedcorrespondingauthoriscorrect,andamendifnecessary.
Answer:Correct
Query:Pleasechecktheaddressforthecorrespondingauthorthathasbeenaddedhere,andcorrectifnecessary.
Answer:Correct
Query:Thecitations“Mayer-Pintoetal.,2017;Firthetal.2014;Strainetal.2017;Strain,Morrisetal.(2017)”havebeenchangedtomatchtheauthorname/yearinthereferencelist.Pleasecheck
hereandinsubsequentoccurrences.
Answer:CitationshavebeencorrectedtoMayer-Pintoetal.,2018andFirthetal.,2014
Query:Pleasenotethat“Fig.5”wasnotcitedinthetext.Pleasecheckthatthecitationsuggestedbythecopyeditorareintheappropriateplace,andcorrectifnecessary.
Answer:Citationscorrected.Fig.5shouldbemovedafterTable4
Query:Refs.Browne&Chapman2014;Meireetal.,2013;Morris,Konlechneretal.,2018;Paalvastetal.,2012arecitedinthetextbutnotprovidedinthereferencelist.Pleaseprovidetheminthe
referencelistordeletethiscitationfromthetext.
Answer:BrowneMA,ChapmanMG.Mitigatingagainstthelossofspeciesbyaddingartificialintertidalpoolstoexistingseawalls.MarineEcologyProgressSeries.2014Feb5;497:119-29.Temmerman
S,MeireP,BoumaTJ,HermanPM,YsebaertT,DeVriendHJ.Ecosystem-basedcoastaldefenceinthefaceofglobalchange.Nature.2013Dec;504(7478):79.PaalvastP,vanWesenbeeckBK,vander
VeldeG,deVriesMB.Poleandpontoonhulas:Aneffectivewayofecologicalengineeringtoincreaseproductivityandbiodiversityinthehard-substrateenvironmentoftheportofRotterdam.Ecological
engineering.2012Jul1;44:199-209.
Query:Havewecorrectlyinterpretedthefollowingfundingsource(s)andcountrynamesyoucitedinyourarticle:IanPotterFoundation,Australia?
Answer:Correct
Query:Uncitedreference:Thissectioncomprisesreferencethatoccurinthereferencelistbutnotinthebodyofthetext.Pleasepositioneachreferenceinthetextor,alternatively,deleteit.Any
referencenotdealtwithwillberetainedinthissection.Thankyou.
Answer:Thereferenceiscitedinthesupplementarysection.
Query:Pleaseconfirmthatgivennamesandsurnameshavebeenidentifiedcorrectlyandarepresentedinthedesiredorderandpleasecarefullyverifythespellingofallauthors’names.
Answer:Correct
Marineecologicalengineeringprojectsrequiregreaterconsiderationofsocialvalues.
Mostusers(>70%)aresupportiveofecologicalengineering.
Boatinginfrastructureinbusytransporthubsarekeyprioritiesforecologicalengineering.
ResidentsinSydneyandMelbournefocusedonimprovingbiodiversity.
ResidentsinHobartweremoreconcernedaboutremediatingpollution.
Query:Yourarticleisregisteredasaregularitemandisbeingprocessedforinclusioninaregularissueofthejournal.IfthisisNOTcorrectandyourarticlebelongstoaSpecialIssue/Collectionplease
contactp.sivakumar@elsevier.comimmediatelypriortoreturningyourcorrections.
Answer:Correct
... Of the 149 participants, 42% completed the survey online and 22% returned the survey through the post. This number of responses is comparable to other public perceptions studies on coastal protection issues (Evans et al., 2017;Kienker et al., 2018;Morris et al., 2016;Strain et al., 2018). ...
... These sampling methods are used to capture cost-effective data which can be used in the early stages of decision-making, raising awareness of the marine environment, and identifying any differences in perspective among key stakeholder groups (e.g. Kienker et al., 2018;Strain et al., 2018), however it can be difficult to get a representative popula-tion sample. To assess this, we compared the data collected via the survey to equivalent census information collected across Victoria and in two of the five locations. ...
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Coastal flooding and erosion cause significant social and economic impacts, globally. There is a growing interest in using natural habitats such as mangroves to defend coastlines. The protective services of mangroves, however, have not been assessed in the same rigorous engineering and socio-economic terms as rock revetments, and therefore are often overlooked by coastal managers. We used field measurements, a social science survey and economic valuation to compare the coastal protection services of mangroves and rock revetments, at five locations across Victoria, Australia. The results showed, in sheltered locations, both mangroves and rock revetments attenuated waves, however, the wave attenuation (per metre) of rock revetments was greater than mangroves, at two of the five locations. Only a small proportion of the survey respondents had observed flooding or erosion in their suburb but most agreed that mangroves provide important coastal protection benefits. Coastal landowners visited areas with mangroves more often than the public but were less likely to worry about the links between climate change and coastal erosion and flooding, or to agree that the coast was well protected with existing artificial coastal infrastructure, than other respondents. There were much higher up-front costs associated with building rock revetments, than planting mangroves, but rock revetments required less land than mangroves. Mangroves covered a larger area and averted more damages than rock revetments. Coastal managers and policy makers will have more success in advocating for nature-based solutions for coastal protection, if they are implemented in locations where they are eco-engineering and socio-economically acceptable options for climate change adaptation.
... Intensification of coastal hazards and urbanisation has resulted in the proliferation of artificial structures, especially hard structures for coastal defence (Borsje et al., 2011;Chapman and Underwood, 2011;Strain et al., 2019). These structures are financially costly to implement and maintain, non-adaptive and ecologically unsustainable (Barbier et al., 2011;Mukhopadhyay et al., 2012;Spalding et al., 2014). ...
... Ecoengineering involves the modification of existing infrastructure (e.g. adding structural complexity or using eco-friendly materials; "hard ecoengineering"; Strain et al., 2019), replacement of infrastructure with rehabilitated or restored habitats ("soft eco-engineering"; French, 2006), or the combination of natural and restored habitat with built infrastructure ("hybrid eco-engineering; Borsje et al., 2011;Spalding et al., 2014;Schueler, 2017(Mitsch, 1996, 2012. Natural and constructed vegetated habitats can provide known coastal protection services (Doswald et al., 2014;Gittman et al., 2014;Van Cuong et al., 2015), and have the potential to provide other co-benefits such as maintenance of wildlife and raw materials or food relative to artificial structures (McLeod et al., 2011;Morris et al., 2018). ...
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There is growing demand for novel coastal protection approaches that also provide co-benefits such as enhanced biodiversity. Rock-fillets, which are used to stabilise eroding banks in estuaries, can be colonised by mangroves, and may provide habitat for estuarine fauna. However, it is unknown whether hybrid mangrove/rock-fillet habitats are functionally equivalent to natural mangroves, for estuarine fauna. To determine whether hybrid mangrove habitats are functionally equivalent to natural mangroves, we used δ¹³C and δ¹⁵N stable isotope analyses to describe the isotopic niche space and overlap of estuarine species in these two habitats across three estuaries in NSW, Australia. Using a Bayesian standard ellipse analysis of isotopic niche area, over half the 12 species observed had larger isotopic niche areas in natural mangroves compared to hybrid habitats, however there were no clear patterns for species between habitats. Natural mangroves and hybrid rock-fillet habitats were isotopically distinct for all species sampled (low proportional overlap, 0–19%) suggesting they are not, at present, wholistically functionally equivalent. Estuarine communities from the two habitat types, however, had similar isotopic niches. Hybrid communities displayed a broader range of δ¹³C values compared to natural mangroves, suggesting mangrove/rock-fillet habitats have a more diverse range of basal food sources. These findings demonstrate the potential for defence solutions to provide unique co-benefits by supporting food webs, but also that natural habitats provide unique ecosystem services that should be protected and rehabilitated where possible. Future modelling and monitoring of habitat utilisation and species performance could provide further insight into the co-benefits and trade-offs of hybrid habitats.
... Although the development and utilization of marine resources can promote social and economic development, it will inevitably affect the marine environment. European and American scholars mainly studied the value of marine resources from the aspects of utilization, protection and sustainable development of marine resources development (Strain et al., 2019). Humphreys and Herbert (2018) comprehensively analyzed the main impacts of marine resources development from the perspective of ecological environment system. ...
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An accurate grasp on the comprehensive benefits and key impact factors of various types of marine resources development can facilitate the rational selection of marine resources development types. It has a certain reference value for the timely adjustment of marine development countermeasures and development direction. In this paper, the Delphi method, entropy weight method and rough set theory are combined for progressive screening, and an evaluation index system of marine resources development is constructed. Principal component analysis (PCA) is used to analyze the driving force of marine resources development. We found that eight indicators in the four element layers of economic cost, resource benefit, resource cost and ecological environment benefit are the key factors influencing the development and utilization of marine resources. Linear weighted sum (LWS) model is used to measure the comprehensive index of five types of marine resources development. We found that the order from high to low is land reclamation 0.3883, sewage dumping 0.3613, marine protected areas 0.2927, offshore wind power 0.2885 and mariculture 0.2729. The priorities in marine resources development in Jiangsu Province are defined. Our analysis suggests the need to improve the comprehensive benefits of marine resources development and utilization by improving the efficiency of marine space development and utilization, developing the value of marine tourism resources, responding to the sensitivity of marine ecological environment in a timely manner, and increasing the fees for the use of sea areas and the prevention and control of marine environmental pollution.
... Ecological engineering can be approached in different ways; by modifying built infrastructure through structural complexity, such as building with more eco-friendly material; by replacing built infrastructure with restored or created habitats; or by combining built infrastructure with restored or created habitats Strain et al., 2019). The selected approach, depending on the ecological objectives and type of environment, contributes to building multi-functional infrastructure to the benefit of both humans and nature (Mitsch, 2012). ...
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The Words into Action (WiA) guidelines series aims to ensure worldwide access to expertise, communities of practice and networks of DRR practitioners. The guidelines offer specific advice on the steps suggested to implement a feasible and people-centered approach in accordance with the Sendai Framework for Disaster Risk Reduction 2015-2030. These guidelines are not meant to be exhaustive handbooks that cover every detail, and those who need more in-depth information will find references to other sources that can provide them with it. Using a knowledge co-production methodology, WiA work groups take a participatory approach that ensures wide and representative diversity in sources of know-how. WiA is primarily a knowledge translation product, converting a complex set of concepts and information sources into a simpler and synthesized tool for understanding risk and learning. It is also meant to be a catalyst for engaging partners and other actors. In summary, the WiA guidelines are pragmatic roadmaps to programming an effective implementation strategy. This is facilitated by promoting a good understanding of the main issues, obstacles, solution-finding strategies, resources and aspects for efficient planning. The guidelines can be a valuable resource for national and local capacity building through workshops and training in academic and professional settings. They can also serve as a reference for policy and technical discussions. For more information about Words into Action, please contact: United Nations Office for Disaster Risk Reduction 9
... Ecological engineering can be approached in different ways; by modifying built infrastructure through structural complexity, such as building with more eco-friendly material; by replacing built infrastructure with restored or created habitats; or by combining built infrastructure with restored or created habitats Strain et al., 2019). The selected approach, depending on the ecological objectives and type of environment, contributes to building multi-functional infrastructure to the benefit of both humans and nature (Mitsch, 2012). ...
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The Words into Action (WiA) guidelines series aims to ensure worldwide access to expertise, communities of practice and networks of DRR practitioners. The guidelines offer specific advice on the steps suggested to implement a feasible and people-centered approach in accordance with the Sendai Framework for Disaster Risk Reduction 2015-2030. These guidelines are not meant to be exhaustive handbooks that cover every detail, and those who need more in-depth information will find references to other sources that can provide them with it. Using a knowledge co-production methodology, WiA work groups take a participatory approach that ensures wide and representative diversity in sources of know-how. WiA is primarily a knowledge translation product, converting a complex set of concepts and information sources into a simpler and synthesized tool for understanding risk and learning. It is also meant to be a catalyst for engaging partners and other actors. In summary, the WiA guidelines are pragmatic roadmaps to programming an effective implementation strategy. This is facilitated by promoting a good understanding of the main issues, obstacles, solution-finding strategies, resources and aspects for efficient planning. The guidelines can be a valuable resource for national and local capacity building through workshops and training in academic and professional settings. They can also serve as a reference for policy and technical discussions. For more information about Words into Action, please contact: United Nations Office for Disaster Risk Reduction 9
... Bishop et al., 2017;Dafforn et al., 2015bDafforn et al., , 2015bSilliman and Bertness, 2004;Strain et al., 2018;Waltham et al., 2020) and human perceptions (e.g. Evans et al., 2017;Scyphers et al., 2015;Strain et al., 2019;Sutton-Grier et al., 2018), to propose specific recommendations related to coastal urban planning. ...
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The comprehensive benefit evaluation of marine resources developmental model is of great significance to choose the appropriate types of marine resources development and promote the intensive utilization and sustainable development of marine resources. This article examined five types of marine resources development, such as marine protected areas, mariculture, offshore wind power, sewage dumping, and land reclamation, and constructed a three-level evaluation index system for the comprehensive benefits of marine resources development. The projection pursuit clustering model was used to evaluate and analyze the comprehensive benefits and main influencing factors of 15 marine resources development projects in Jiangsu Province, China. It was found that the comprehensive benefit projection values of marine protected areas and offshore wind power are higher. The projection value of comprehensive benefit of land reclamation is the lowest. The main influencing factors include but not limited to the change rate of total output of aquatic products, contradiction between management and marine use, negative impact on residents’ lives, etc. The research results have important guiding significance for promoting the rational development and utilization of marine resources and the high-quality development of the oceans.
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Urban areas confront a number of environmental issues including excessive thermal stress and concentrated emissions of greenhouse gases and pollutants. In past decades, many mitigation strategies have been designed and implemented to counteract these issues and ameliorating the environmental quality in cities, which can be broadly classified as white, green or blue infrastructure. The functioning and efficacy of urban mitigation strategies involve complex interactions between landscape dynamics, anthropogenic activities, and atmospheric transport, which leads to compound, rather than singular, environmental impact. In this study, we conducted a critical review of the compound environmental impact of urban mitigation strategies, and evaluated, besides the targeted cooling effect, the resultant co-benefits, trade-offs, or unintended consequence, in terms of building energy saving, air quality improvement, carbon emission offset, and impact to human health. Furthermore, we proposed a novel mathematical framework that is capable of assessing the compound environmental impact in a unified way, together with some preliminary results as the proof-of-concept. A number of knowledge gaps are identified which calls for future transdisciplinary synergy among urban engineers, atmosphere and climate scientists, and epidemiologists.
Technical Report
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Nature-based methods use the creation or restoration of coastal habitats for hazard risk reduction. This can be done through restoring the habitat alone (“soft” approach), or in combination with hard structures that support habitat establishment (“hybrid” approaches). The need to develop, test and apply more sustainable techniques to mitigate the impacts of coastal hazards has been identified as a national priority. One reason that nature-based methods have been underutilised in Australia is that decision-makers need clearer guidelines for when a soft, hybrid or hard coastal defence approach is most appropriate. International exemplars in nature-based methods have started this process, which include Ecoshape’s Building with Nature in Europe and the Army Corps of Engineers’ Engineering-with-Nature® in the United States. Here we build on this international knowledge and national research efforts to provide an Australian context for nature-based methods, as wider adoption of these techniques nationally requires accounting for the environmental, economic and socio-political contexts specific to Australia. This guideline summarises the physical processes that underpin nature-based methods, and the ecological and engineering considerations for their application based on the major coastal ecosystems found in Australia. It also provides frameworks for implementing nature-based methods and conducting a benefit-cost analysis, and the policy landscape within which nature-based methods can be applied. The aim of this document is to translate the known global and Australian research into a practical tool that can be used to support decisions by coastal practitioners to use nature-based methods.
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Urban and periurban ocean developments impact 1.5% of the global exclusive economic zones, and the demand for ocean space and resources is increasing. As we strive for a more sustainable future, it is imperative that we better design, manage, and conserve urban ocean spaces for both humans and nature. We identify three key objectives for more sustainable urban oceans: reduction of urban pressures, protection and restoration of ocean ecosystems, and support of critical ecosystem services. We describe an array of emerging evidence-based approaches, including greening gray infrastructure, restoring habitats, and developing biotechnologies. We then explore new economic instruments and incentives for supporting these new approaches and evaluate their feasibility in delivering these objectives. Several of these tools have the potential to help bring nature back to the urban ocean while also addressing some of the critical needs of urban societies, such as climate adaptation, seafood production, clean water, and recreation, providing both human and environmental benefits in some of our most impacted ocean spaces. Expected final online publication date for the Annual Review of Marine Science, Volume 13 is January 3, 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Urbanisation and population growth continue to impact already pressured harbour environments, resulting in a proliferation of artificial structures in the marine environment. In response, there is a growing interest in ecological engineering these structures for the benefit of both nature and humankind. Since the decision to build or adapt coastal infrastructure is a socio-economic one, the views and perceptions of different users are likely to influence support for ecological engineering projects. A survey was developed and run in four harbours (Sydney, Hobart, Auckland and Tauranga) to quantify the perceptions of different stakeholder groups towards ecological engineering of artificial structures. This study tested whether respondents with a greater connection, concern for environment, with a higher socioeconomic status or who lived in a more modified harbour environment are more likely to be supportive of ecological engineering than other respondents. The study also assessed whether respondents with prior knowledge about the dominant artificial structure in their harbour (seawalls) agreed with the positive effects, disagreed with negative effects, and were more willing to contribute to costs of ecological engineering than those without prior knowledge. Results showed that most people are supportive of ecological engineering (92.55%). However, stakeholders whose work is directly linked to the harbour are more supportive of ecological engineering in Sydney and Auckland, than in Tauranga or Hobart. Environmental concern, education, income and level of harbour modification all have a positive influence on support for ecological engineering. Prior knowledge also influenced willingness to pay for ecological engineering. These results are promising for councils and managers seeking to implement ecological engineering initiatives, and looking to understand stakeholder groups’ attitudes and perceptions towards ecological engineering initiatives. Greater consideration of both ecology and public users’ values are required for more holistic management strategies of artificial structures in urban marine harbours.
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Many studies have argued that a better understanding of people’s preferences about publicurban green spaces may inform urban planners to effectively provide and manage urban green spacesto meet users’ needs. The aim of this study is to examine urban residents preferred public greenspace characteristics and investigate whether similarities and differences can be highlighted in threedifferent Portuguese cities. Through a web-based questionnaire based on the best-worst scaling(BWS) method, residents of Lisbon, Porto andÉvora (n= 750) were asked to select the most andleast important public green space characteristic among thirteen attributes. The results suggest aconsensus about some green space characteristics across cities but also the existence of some localvariations in city residents’ preferences. Overall, this study can support public authorities and urbanplanners as they strive to effectively design and manage urban green spaces to meet users’ needs
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Urban areas have broad ecological footprints with complex impacts on natural systems. In coastal areas, growing populations are advancing their urban footprint into the ocean through the construction of seawalls and other built infrastructure. While we have some understanding of how urbanisation might drive functional change in terrestrial ecosystems, coastal systems have been largely overlooked. This study is one of the first to directly assess how changes in diversity relate to changes in ecosystem properties and functions (e.g. productivity, filtration rates) of artificial and natural habitats in one of the largest urbanised estuaries in the world, Sydney Harbour. We complemented our surveys with an extensive literature search. We found large and important differences in the community structure and function between artificial and natural coastal habitats. However, differences in diversity and abundance of organisms do not necessarily match observed functional changes. The abundance and composition of important functional groups differed among habitats with rocky shores having 40% and 70% more grazers than seawalls or pilings, respectively. In contrast, scavengers were approximately 8 times more abundant on seawalls than on pilings or rocky shores and algae were more diverse on natural rocky shores and seawalls than on pilings. Our results confirm previous findings in the literature. Oysters were more abundant on pilings than on rocky shores, but were also smaller. Interestingly, these differences in oyster populations did not affect in situ filtration rates between habitats. Seawalls were the most invaded habitats while pilings supported greater secondary productivity than other habitats. This study highlights the complexity of the diversity-function relationship and responses to ocean sprawl in coastal systems. Importantly, we showed that functional properties should be considered independently from structural change if we are to design and manage artificial habitats in ways to maximise the services provided by urban coastal systems and minimise their ecological impacts.
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1. Nearshore ecosystems are increasingly recognized as critical habitats for fish of cultural, ecological and economic significance. These ecosystems are often densely inhabited by juvenile fish, highly productive and refuges from predation, leading ecologists to characterize them as nurseries. However, nearshore ecosystems are being transformed globally to support demands of growing coastal populations. Many shorelines are modified by armouring (e.g. seawalls, riprap) that minimizes erosion, and overwater structures (e.g. piers, docks) that facilitate waterfront use. These modifications affect the ecology of nearshore systems by restructuring, eliminating and shading shallow waters. 2. Here, we review literature examining effects of armouring and overwater structures on coastal and estuarine fishes, and discuss how research and management can coordinate to minimize negative effects. 3. Along armoured shorelines, fish assemblages differed from unarmoured sites, fish con- sumed less epibenthic and terrestrial prey, beach spawning was less successful and fish were larger. Under large overwater structures, visually oriented fish were less abundant and they fed less. Shade from overwater structures also interrupted localized movements of migratory fish. Thus, shoreline modifications impaired habitats by limiting feeding, reproduction, onto- genetic habitat shifts from shallow to deeper waters and connectivity. 4. Research suggests that restoring shallow waters and substrate complexity, and minimizing shading underneath overwater structures, can rehabilitate habitats compromised by shoreline modifications. 5. Synthesis and applications. Shoreline armouring and overwater structures often compro- mise fish habitats. These threats to nearshore fish habitats will become more severe as grow- ing coastal populations and rising sea levels increase demands for shoreline infrastructure. Our ability to assess and rehabilitate nearshore fish habitats along modified shorelines will be enhanced by: focusing research attention on metrics that directly indicate fish habitat quality; implementing and evaluating shoreline features that repair compromised habitat functions within human-use constraints; collating natural history knowledge of nearshore ecosystems; and embracing the socio-ecological nature of habitat improvements by educating the public about conservation efforts and fostering appreciation of local nearshore ecosystems. Actions to reduce impacts of shoreline modifications on fish are particularly feasible when they align with societal goals, such as improving flood protection and providing spaces that facilitate recreation, education, and connections between people and nature.
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Extensive development and construction in marine and coastal systems is driving a phenomenon known as “ocean sprawl”. Ocean sprawl removes or transforms marine habitats through the addition of artificial structures and some of the most significant impacts are occurring in sedimentary environments. Marine sediments have substantial social, ecological, and economic value, as they are rich in biodiversity, crucial to fisheries productivity, and major sites of nutrient transformation. Yet the impact of ocean sprawl on sedimentary environments has largely been ignored. Here we review current knowledge of the impacts to sedimentary ecosystems arising from artificial structures.
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The growing number of artificial structures in estuarine, coastal and marine environments is causing “ocean sprawl”. Artificial structures do not only modify marine and coastal ecosystems at the sites of their placement, but may also produce larger-scale impacts through their alteration of ecological connectivity - the movement of organisms, materials and energy between habitat units within seascapes. Despite the growing awareness of the capacity of ocean sprawl to influence ecological connectivity, we lack a comprehensive understanding of how artificial structures modify ecological connectivity in near- and off-shore environments, and when and where their effects on connectivity are greatest. We review the mechanisms by which ocean sprawl may modify ecological connectivity, including trophic connectivity associated with the flow of nutrients and resources. We also review demonstrated, inferred and likely ecological impacts of such changes to connectivity, at scales from genes to ecosystems, and potential strategies of management for mitigating these effects. Ocean sprawl may alter connectivity by: (1) creating barriers to the movement of some organisms and resources - by adding physical barriers or by modifying and fragmenting habitats; (2) introducing new structural material that acts as a conduit for the movement of other organisms or resources across the landscape; and (3) altering trophic connectivity. Changes to connectivity may, in turn, influence the genetic structure and size of populations, the distribution of species, and community structure and ecological functioning. Two main approaches to the assessment of ecological connectivity have been taken: (1) measurement of structural connectivity - the configuration of the landscape and habitat patches and their dynamics; and (2) measurement of functional connectivity - the response of organisms or particles to the landscape. Our review reveals the paucity of studies directly addressing the effects of artificial structures on ecological connectivity in the marine environment, particularly at large spatial and temporal scales. With the ongoing development of estuarine and marine environments, there is a pressing need for additional studies that quantify the effects of ocean sprawl on ecological connectivity. Understanding the mechanisms by which structures modify connectivity is essential if marine spatial planning and eco-engineering are to be effectively utilised to minimise impacts.
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Macroalgal beds provide important habitat structure and support primary production for rocky reef communities, but are increasingly degraded as a result of human pressures. Various sources of pollution can have both direct and interactive effects on stressed ecosystems. In particular, interactions involving invertebrate grazers could potentially weaken or strengthen the overall impact of pollution on macroalgal beds. Using a paired impact-control experimental design, we tested the effects of multiple pollution sources (fish farms, marinas, sewerage, and stormwater) on translocated and locally established algal assemblages, while also considering the influence of invertebrate grazers. Marinas directly affected algal assemblages and also reduced densities of amphipods and other invertebrate mesograzers. Fish farms and sewerage outfalls tended to directly increase local establishment of foliose and leathery algae without any indication of changes in herbivory. Overall, pollution impacts on algae did not appear to be strongly mediated by changes in grazer abundance. Instead, mesograzer abundance was closely linked to availability of more complex algal forms, with populations likely to decline concurrently with loss of complex algal habitats. Macrograzers, such as sea urchins, showed no signs of a negative impact from any pollution source; hence, the influence of this group on algal dynamics is probably persistent and independent of moderate pollution levels, potentially adding to the direct impacts of pollution on algal beds in urbanised environments.
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To successfully integrate and engage the general public into marine conservation decisions it is important that individuals are well informed. This study surveyed two sample groups, marine environmental professionals working in the UK, n = 61, and members of the public surveyed in Truro, Cornwall, UK, n = 71. Public awareness of marine environmental threats and conservation efforts was assessed through comparison with the, assumed well informed, professional sample. Findings suggest that the public are generally well informed of threats to the marine environment, but are significantly less well informed about marine conservation and management strategies. Furthermore, despite indicating concern for the marine environment, members of the public display significantly fewer pro-environmental behaviours than marine conservation professionals. Public knowledge (and action) gaps are discussed as well as how these may be minimised, including a more interdisciplinary and active approach to science communication and public engagement.
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Public perception research enhances the governance of coastal hazard mitigation. Understanding the public's awareness and perceptions of hazard mitigation infrastructure is an important aspect of effective governance. Emerging federal policies call for more integrated use of engineered and natural infrastructure for mitigating coastal hazards. This study is to assess public awareness and perception of the functions of and relationship between engineered and natural infrastructure, which is critical to the successful implementation of such policies. Semi-structured interviews were conducted to 27 residents from two coastal communities in New Jersey. Thematic content analysis is used to analyze these interview data. The study shows that awareness of mitigation infrastructure stems in part from experience with coastal hazards. Many participants understood the functions of both types of infrastructure in ways that were consistent with the understandings of coastal engineers, but did not fully understand how these two types of infrastructure interact each other to mitigate coastal hazards. Most respondents preferred natural infrastructure, but believed that engineered infrastructure is more effective in coastal hazard mitigation. The knowledge of public perceptions of mitigation infrastructure would be useful to coastal managers in developing and communicating coastal hazard mitigation strategies.