OrganizationsandPersonnel

Directedby

DepartmentofMarineEarlyWarningandMonitoring,MinistryofNaturalResources,PRChina

Preparedby

NationalMarineHazardMitigationService,MinistryofNatureResourcesNanjingUniversity

FudanUniversity

TheFirstInstituteofOceanography,MinistryofNaturalResourcesCCCCWaterTransportationConsultantsCo.,Ltd.

HohaiUniversity

ZhejiangInstituteofHydraulics&Estuary(ZhejiangInstituteofMarinePlanningandDesign)

NorthChinaSeaEcologicalCenteroftheMinistryofNaturalResourcesEastChinaSeaEcologicalCenteroftheMinistryofNaturalResourcesSouthChinaSeaEcologicalCenteroftheMinistryofNaturalResources

SouthChinaSeaInstituteofPlanningandEnvironmentalResearch,StateOceanicAdministration

TheSecondInstituteofOceanography,MinistryofNaturalResourcesTheThirdInstituteofOceanography,MinistryofNaturalResources

TheFourthInstituteofOceanography,MinistryofNaturalResources

Authors

XinpingChen,PingZuo,YangZheng,BoLi,WeiWang,AifengTao,JianZeng,LiSun,HongshuaiQi,GuoyiWen,LeWang,QiangHe,YuxingWang,XunanLiu,ZibinLi,YuHan,ZhixingGuo,HouleiJia,ZhaohuiZhang,ZheFeng,JuntingZhou,YonghuaTan,YanhongAn,FeiWang,TengWang,MingliZhao,YuCao,ShuoYu,ZiyiDai

HandbookofEcosystemRestorationforCoastalHazardMitigation:CoastalSaltMarshes

INTRODUCTION

Naturaldisastersareamongthemostpressingglobalchallengesfacinghumanitytoday.Toeffectivelyaddresstheirsevereimpacts,approachessuchasNature-basedSolutions(NbS)andEcosystem-basedDisasterRiskReduction(Eco-DRR)havegainedsignificantglobalattention.Thesestrategiesaimtoleverageecosystemservicesfordisastermitigationthroughtheprotection,restoration,andsustainablemanagementofecosystems,ultimatelyensuringsustainableandresilientsocio-economicdevelopment.TheseapproachesarehighlyalignedwithChina’svisionofecologicalcivilizationanditsmodernprinciplesofdisasterpreventionandmitigation.

Incoastalareas,ecosystemssuchassaltmarshes,oysterreefs,sandyshores,andseagrassbedsserveasnaturalbuffers,protectingagainsttidesandwaveswhilereinforcingembankmentsandsafeguardingshorelines.Theseecosystemsactas “guardiansofthesea,”playingacrucialroleinmitigatingtherisksofmarinedisasters.Throughtheecologicalprotectionandrestorationofcoastalzones,thedisastermitigationfunctionsoftheseecosystemscanbefullyrealized,enhancingtheabilityofcoastalareastowithstandtyphoons,stormsurges,andothermarinehazards.Toguidepracticalworkinthisfield,theMinistryofNaturalResourceshaslaunchedaseriesofhandbooksoncoastalecosystemrestoration.Thesehandbooksaimtointegrateecologicalbenefitswithmarinehazardmitigation,focusingontherestorationofcoastalsaltmarshes,oysterreefs,sandyshores,andseagrassbeds.Theyofferdetailedguidanceonecologicalbaselinesurveys,problemdiagnosis,restorationobjectives,interventionmeasures,andtheentirechainoftechnicalsteps,includingmonitoring,evaluation,andadaptivemanagement.Emphasizingscience

HandbookofEcosystemRestorationforCoastalHazardMitigation:CoastalSaltMarshes

popularisation,practicality,andoperability,thehandbooksareconciseandwell-illustrated,providingvaluabletechnicalsupportforthescientificimplementationofecologicaldisastermitigationandrestorationincoastalareas.

ThisseriesofhandbookshasbeendevelopedwithsupportfromtheMinistryofFinanceandtheInternationalUnionforConservationofNature(IUCN),towhomweexpressoursinceregratitude.Wealsoextendourappreciationtothepractitionersandexpertsdedicatedtocoastalzoneecologicaldisastermitigationandrestoration.

Duetothelimitedtimeandresourcesavailableforthepreparationofthesehandbooks,theremaybeunavoidableshortcomings.Wewelcomeyourfeedbackandsuggestionsforimprovement.

HandbookofEcosystemRestorationforCoastalHazardMitigation:CoastalSaltMarshes

V

CONTENTS

1.ScopeofApplication 1

2.TermsandDefinitions 2

3.RestorationPrinciples 4

4.OverallTechnicalProcess 6

5.BaselineSurvey 8

5.1SurveyObjectives 8

5.2SurveyContent 8

5.3SurveyMethods 10

6.ProblemDiagnosisandSuitabilityAssessmentfor

Restoration 18

6.1ProblemDiagnosis 18

6.2SuitabilityAssessmentforRestoration 20

7.RestorationGoals 21

7.1Medium-toLong-TermGoals 22

7.2Short-termObjectives 24

8.RestorationMethods 25

9.RestorationMeasures 28

9.1HabitatRestoration 28

9.2PlantRestoration 41

HandbookofEcosystemRestorationforCoastalHazardMitigation:CoastalSaltMarshes

VI

9.3InvasiveSpeciesControlTechniques 52

9.4ConstructionofCoastalIntegratedProtectionSystem 54

9.5Post-restorationStewardship 56

10．Follow-upMonitoring,EffectAssessmentandAdaptive

Management 60

10.1Follow-upMonitoring 60

10.2RestorationEffectAssessment 66

10.3AdaptiveManagementofEcologicalRestoration 69

11.ClassicCasesofCoastalSaltMarshesRestoration 71

11.1Case1—TheCoastofYellowRiverEstuary,Dongying,China 71

11.2Case2—RestorationofcoastalsaltmarshecosysteminHangu,Tianjin

78

Appendix:KnowledgeofCoastalSaltMarshes 84

1.CharacteristicsandTypesofCoastalSaltMarshes 84

2.DistributionofCoastalSaltMarshes 85

3.DiversityCharacteristicsofCoastalSaltMarshPlantCommunities 86

4.EnvironmentalFactorsAffectingCoastalSaltMarshEcosystems 87

5.EcosystemServicesofCoastalSaltMarshes 88

6.MainThreatFactorstoCoastalSaltMarshes 90

7.CoastalSaltMarshPlants 91

References 97

HandbookofEcosystemRestorationforCoastalHazardMitigation:CoastalSaltMarshes

1.ScopeofApplication

ThishandbookisdesignedforapplicationintherestorationofcoastalsaltmarshecosystemsinChina,focusingonachievingco-benefitsinecologicalsignificanceandmarinehazardmitigation.Itappliestotherestorationofcoastalsaltmarsheswithinaspecificrange,aswellasareasthatwerehistoricallycoastalsaltmarshesbuthavebeenconvertedtomudflatsoraquacultureponds.

Thishandbookoutlinesthetechnicalrequirementsandmethodscorrespondingtotheprinciples,technicalprocesses,restorationgoalsandmethods,andrestorationmeasuresforcoastalsaltmarshecologicalrestoration.

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HandbookofEcosystemRestorationforCoastalHazardMitigation:CoastalSaltMarshes

2.TermsandDefinitions

Thefollowingtermsanddefinitionsapplytothistechnicalhandbook.

(1)SaltMarshes

Wetlandscontaininghighlevelsofsaltandsupportingthegrowthofhigherplants.

Note:Coastalsaltmarshesaredistributedinestuariesorcoastalshallowwaters,formedbyseawaterimmersionortidalalternation.

(2)SaltMarshVegetation

Plantcommunitiesgrowinginsaltmarshes.

Note:ThemaindominantplantsincoastalsaltmarshesinChinaincludereeds(Phragmitesaustralis),smoothcordgrass(Spartinaalterniflora),Scirpusmariqueter,Suaedasalsa,andCyperusmalaccensisvarbrevifolius.Amongthem,SpartinaalternifloraislistedasoneofthethefirstbatchofinvasivespeciesinChina.

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HandbookofEcosystemRestorationforCoastalHazardMitigation:CoastalSaltMarshes

(3)CoastalSaltMarshEcosystem

Anecosystemprimarilyconsistsofsaltmarshvegetation,alongwithotherplants,animals,microorganisms,soil,andwaterbodies.Thesecomponentsareinterdependent,mutuallyrestrictive,andinteractwiththeenvironment.

(4)CoastalSaltMarshEcologicalRestoration

Theprocessinvolvesrestoringthebiologicalcommunities,ecosystemfunctions,andservicesofcoastalsaltmarshecosystemstotheirnativestate.Thisisachievedbyintroducingpropagulesofcoastalsaltmarshplantsintodegradedareasorbyimprovingthehabitatconditionsofexistingcoastalsaltmarshes.

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HandbookofEcosystemRestorationforCoastalHazardMitigation:CoastalSaltMarshes

4

3.RestorationPrinciples

Thecoastalsaltmarshesecosystemrestorationforthemarinehazardmitigationshouldadheretothefollowingprinciples:

(1)Tailoredwithcategorizedmeasuresspecifictoeachsite.GiventheextensivedistributionofcoastalsaltmarshesinChinaandthediversenaturalconditionsacrossregions,aswellasthevariouscausesofecosystemdegradation,restorationeffortsshouldbetailoredtogeographicallocation,climatecharacteristics,andplanttypes,amongotherfactors.Considerationshouldbegiventofunctionalneeds,technicalconditions,economicfoundation,andotherfactorstodevelopsuitablelayouts,implementationstrategies,andtechnicalroutesforecologicalrestoration.Thisapproachpromotestargetedandeffectiveecologicalrestorationprojects,withsite-specificcategorizedmeasuresbeingdeveloped.

(2)Naturalrecoveryasprimary,artificialrestorationassupplementary.Followtheinherentmechanismsandsuccessionlawsofcoastalsaltmarshesandothernaturalecosystems,adheringtoecologicalprinciplestomaintainecosystemdiversityandconnectivity.Emphasizetheself-restorationabilityofecosystems,whileminimizingunnecessaryinterferencefromhumanactivities.Incaseswherenaturalecosystemrestorationisunattainable,appropriateartificiallyassistedmeasuresshouldbetaken.Thesemeasuresshouldbebasedonexistingnaturalconditions,andphasedstepsshouldbetakenaccordingtothesuccessionpatternoftheecosystem

itselftopromoteecosystemrestoration.

(3)Systematicandholisticrestorationforsynergisticecologyanddisastermitigation.Consideringtheinteractionsbetweenthelandandseaofcoastalsaltmarshesinanintegratedmanner,andstartingfromtheintegrityoftheecosystem,thegoalistoenhancetheecosystemservicefunctionsandresilienceofthecoastalzone.Thesystematicnatureofecologicalrestorationactivitiesintermsofspatialandtemporalcontinuityshouldbefullyconsidered,achievingharmoniousmultifacetedevolutionofhydrology,soil,vegetation,andbiologicaldiversity,andpromotingthe

HandbookofEcosystemRestorationforCoastalHazardMitigation:CoastalSaltMarshes

synergisticeffectsofcoastalzoneecologyanddisastermitigation.

(4)Maximumbenefitswithrisksmanageable.Restorationactivitiesshouldundergosystematicandcomprehensiveanalysisanddemonstrationtofullyconsiderthecomplexityofecosystemsandthemutabilityofcertainenvironmentalelements.Thisconsiderationhelpsavoidnegativeimpactsontherestorationandsurroundingareas,minimizingrisks.Effortsshouldbemadetoachievemaximumbenefitswithminimalrisksandinvestments,consideringecologicalanddisastermitigationbenefits,aswellassocialandeconomicbenefits.Thisapproachaimstomaximizeecological,disastermitigation,social,andeconomicbenefitswhileminimizingrisksandinvestments.

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HandbookofEcosystemRestorationforCoastalHazardMitigation:CoastalSaltMarshes

4.OverallTechnicalProcess

Theoveralltechnicalprocessformitigatingmarinehazardsthroughcoastalsaltmarshecosystemrestorationinvolvesseveralpivotalstages.Theseincludeconductingecologicalbaselinesurveys,diagnosingecologicalissues,establishingrestorationgoalsandmethods,formulatingrestorationplans,implementingengineeringprojects,conductingfollow-upmonitoring,evaluatingeffectiveness,assessingimpacts,andemployingadaptivemanagementstrategies.RefertoFigure1foradetailedoverview.

6

HandbookofEcosystemRestorationforCoastalHazardMitigation:CoastalSaltMarshes

Determinetheecologicalrestorationandecologicalsurveyarea

Managementand

Ecologicalbaselinesurvey

utilization

Vegetation

conditions

Habitat

conditions

Threatening

factors

other

Referenceecosystem

Diagnosisofecologicalproblems

Determinationofrestorationgoal

Baselinestateofdegradedecosystem

Degenerationfactors,degreesandcauses

Ecosystemstructure

Importantecological

process

Importantecological

function

Determinationofrestorationmethod

Reconstructiverestoration

----------?

Naturalrestoration

Artificialassistedrestoration

Compilationofrestorationplan

Eliminationofstressfactors

pest

Pollutantdischarge

Humanactivities

Otherfactors

Restorationofhabitatelements

Hydrodynamicconditions

topography

Sediment

environment

Other

conditions

Artificialvegetationrestoration

Plantingarea

Speciesselection

Plantingmode

plantingplan

Follow-upmonitoring

Specificobjectivesofecologicalrestoration

Specificprojectimplementation

Phasedacceptance

Finalacceptance

Restorationprojectimplementation

----------?

Follow-upmonitoring,effectevaluationandadaptivemanagement

Ecosystemcomponents

Ecosystemprocess

Socio-economicfactors

Adaptivemanagement

----------?

Evaluationofecologicalrestorationeffect

Thephasedgoalofecologicalrestorationhasbeenrealized

Realizationofthegoalofecosystemrestoration

----------?

Figure1FlowChartofCoastalSaltMarshEcosystemRestorationfortheCo-benefitsofEcologicalSignificanceandMarineHazardMitigation

7

HandbookofEcosystemRestorationforCoastalHazardMitigation:CoastalSaltMarshes

5.BaselineSurvey

5.1SurveyObjectives

Theobjectiveoftheecologicalbaselinesurveyistoassessthecurrentstatusofthesaltmarshandevaluatethehistoricaldistributionofsaltmarshesinthearea.Thisservesasthefoundationforanalyzingtheextentofsaltmarshdegradation,establishingrestorationgoals,selectingrestorationmethods,anddevisingecologicalrestorationplans.Additionally,itprovidescomparativedatatoevaluatetheeffectivenessofsaltmarshrestorationefforts.

5.2SurveyContent

Athoroughsurveyoftheareaslatedforrestorationisessentialtograsptheecosystem’sbaselinestatuspre-restoration.Keycomponentsofthecoastalsaltmarshesbaselinesurveyincludeareastatus,saltmarshvegetation,habitatconditions,threatfactors,disastermitigationcapacity,carbonsequestrationandstorage,andothercrucialecologicalfunctions(refertoTable1forspecifics).

Additionally,historicalreferencedataonbaselinesurveysofcoastalsaltmarshecosystemsshouldbecollectedandorganized.

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HandbookofEcosystemRestorationforCoastalHazardMitigation:CoastalSaltMarshes

Table1ContentandIndicatorsofEcologicalBaselineSurveyofCoastalSaltMarshes

Category

SurveyElement

Indicator

SurveyMethod

StatusoftheArea

GeographicAttributes

Specificlocationandgeographiccoordinates

Datacollection

andremote

sensingsurvey

EnvironmentalOverview

Naturalconditions,ecologicalcharacteristics,environmentalstatus

On-siteSurvey

PoliciesandRegulations

Lawsandregulations,planning

Datacollection

Statusof

Protection,

Restoration,and

Utilization

Statusofownership/tenureanduseofrestorationareas,territorialspatialplanning,statusofprotectionofotherimportanthabitats,etc.

Datacollection

SaltMarshVegetation

SaltMarsh

Area,distribution,widthofvegetationbelt

Remotesensingsurveyandon-siteverification

PlantCommunity

Species,density,coverage,averageheight,abovegroundbiomass,netprimaryproductivity

On-siteSurvey

Natural

Regenerationof

Vegetation

Phenology,propaguleproduction,numberofseedlings,etc.

On-siteSurvey

EnvironmentalFactors

Substrate

Environment

Particlesize,totalsolublesaltcontent,pHvalue,organiccarbon,redoxpotential,totalnitrogen,totalphosphorus,sulfide

On-siteSurvey

WaterQualityEnvironment

Turbidity,dissolvedoxygen,pHvalue,organiccarbon,ammonium,nitrate,nitrite,activephosphate

On-siteSurvey

HydrologicalEnvironment

Temperature,salinity,tidalcurrents,waves

TopographyandGeomorphology

Waterdepth,elevation,geomorphologicalunits(coastalzonetypes)

On-siteSurvey

BiologicalCommunity

Macrobenthos

Species,density,biomass

On-siteSurvey

Birds

Species,quantity

On-siteSurvey

9

HandbookofEcosystemRestorationforCoastalHazardMitigation:CoastalSaltMarshes

Category

SurveyElement

Indicator

SurveyMethod

ThreatFactors

NaturalFactors

Naturaldisasters,sealevelchanges,coastalerosion,invasionofalienspecies,etc.

Datacollection,

on-sitesurvey,

socialsurvey,

etc.

HumanFactors

Aquacultureactivities,grazingactivities,fishingactivities,coastalzoneengineering,pollutiantdischargestatus,utilizationofsurroundingresources,tourismdevelopmentactivities,invasionofalienspecies,etc.

Datacollection,

on-sitesurvey,

socialsurvey,

etc.

ImportantEcologicalFunctions

Disaster

Prevention

andMitigation

Functions

Functionssuchaswaveattenuationandshoreprotectionfordisasterpreventionandmitigationandcoastalprotection

Datacollection

andon-site

Survey

Carbon

Sequestration

andSink

Enhancement

Functions

Carbonstocks:biomasscarbondensity,deadorganicmattercarbondensity,sedimentcarbondensity

Datacollection,

on-sitesurvey,

socialsurvey,

etc.

Carbonsink:carbonburialrate,growthrateandroot-to-shootratio(woodyplants),carbonflux,GreenhousegasemissionfactorssuchasCH4,etc.

Datacollection,

on-sitesurvey,

socialsurvey,

etc.

5.3SurveyMethods

Theecologicalbaselinesurveyprimarilyreliesondatacollection,remotesensinganalysis,andfieldsurveys.Specificsurveymethodsforvariouscomponentssuchasareastatus,saltmarshvegetation,habitatconditions,biologicalcommunities,threatfactors,andimportantecologicalprocessesandfunctionsareoutlinedbelow.

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HandbookofEcosystemRestorationforCoastalHazardMitigation:CoastalSaltMarshes

5.3.1StatusoftheArea

Throughdatacollectionandfieldsurveys,thesurveyshouldaimtounderstandthelandspatialplanning,ecologicalredlineareaprotectionplanning,andotherrelatedplanningintheareaearmarkedfortherestorationprojectanditsenvirons.Additionally,assessthecurrentstatusofecosystem-relatedprotectionandmanagement,tenurestatusofthearea,landusestatus,marineuserightscertificates,analyzepotentialsocialimpactsofcoastalsaltmarshecologicalrestoration,identifystakeholders,andgrasptheoverallsituationoftheproposedrestorationarea.

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HandbookofEcosystemRestorationforCoastalHazardMitigation:CoastalSaltMarshes

12

5.3.2SaltMarshVegetation

Surveyingsaltmarshvegetationispivotalintheecologicalbaselinesurvey.Indicatorssuchassaltmarshareaanddistributionareobtainedthroughremotesensingsurveysandon-siteverification.Thewidthofsaltmarshvegetationbeltsiscalculatedbasedontheaveragelengthofsaltmarshhabitatsintheverticalshorelinedirection.Theaveragecoverageof

sampleplotsiscalculatedastheaveragecoverageofeachquadrat.Above-ground

biomassismeasuredbyharvestingtheabove-groundpartsofplantswithinthe

quadrat.

Plantcommunitycharacteristicsaresurveyedon-site.Representativesurveysectionsinsaltmarshareasshouldbeselectedreasonably,andsurveystationsshouldbeestablished.

Whensettingupsurveysections,followprinciplesofcomprehensiveness,typicality,andrepresentativeness.Specifically,thenumberofsectionstationsshouldcomprehensivelyconsiderfactorssuchasdistributionarea,location,andplantspecies.Thelayoutofsectionsshouldspatiallycovertheentiresurveyarea,including

allrepresentativeplantcommunitytypes,andensurethattypicalandspecialplantcommunitiesinthesurveyareareceivefocusedanddetailedsurveys.Thisensuresa

HandbookofEcosystemRestorationforCoastalHazardMitigation:CoastalSaltMarshes

balancedlayoutofsurveysectionsthatcanreflecttheoverallsituationofsaltmarshvegetationinthesurveyareaandprovideabasisforcommunityreviewandlong-termmonitoringforcontinuousmanagement.Tofullyreflecttheintertidalzoneofvegetationdistribution,atleastthreesurveystationsshouldbesetupforeachsectioninprinciple,andwhentypicalandspecialbiologicalcommunitiesarenotcoveredbythesection,separatesurveystationsshouldbeestablished.

Inparallel,plantcommunitycharacteristicsareassessedthroughplotsurveys.Typically,eachstationestablishesasampleplot,oftenmeasuring10m×10m,withfivequadratspositioned(typicallyatthefourcornersandcenterofthesampleplot,asshowninFigure2).Thesizeofeachquadratshouldbedeterminedbasedontheplantspeciesanddistributioncharacteristics,withastandardareaof1m×1m.Incasesofhighplantdensityanduniformdistribution,thequadratareamaybereducedto0.5m×0.5m.Conversely,inscenarioswithdiverseplantspeciesandunevendistribution,allquadratsshouldbesurveyed.Forinstanceswhereplantspeciesaresingularanddistributionisuniform,aminimumofthreequadratsshouldbesurveyed.

Figure2DesignDrawingsofSamplePlotsandQuadrats

5.3.3EviromentalElements

Thesurveyofenvironmentalelementsencompassesthesubstrateenvironment,waterqualityenvironment,hydrologicalconditions,aswellastopographicand

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HandbookofEcosystemRestorationforCoastalHazardMitigation:CoastalSaltMarshes

14

geomorphologicalfeatures(seeTable1).Ifdatafortheseenvironmentalparametersareunavailablefromexistingsourcesorareinsufficienttoassessthehabitatsuitabilityofcoastalsaltmarshes,on-sitesurveysshouldbeconductedtoobtainthenecessaryinformation.

Thesubstrateenvironmentsurveyshouldbeconductedconcurrentlywiththeplantcommunitysampleplotsurvey.Samplesshouldbecollectedwithintheplotsdesignatedforplantcommunitysurveys,withonesamplecollectedateachstation.Thesubstrateenvironmentsurveyprimarilyincludesindicatorssuchasgranularity,totalwater-solublesaltcontent,pHvalue,organiccarbon,redoxpotential,totalnitrogen,total

phosphorus,sulfides,etc.Samplingshouldaimtoavoidlow-lyingwaterloggedareaswheneverfeasible.Duringsampling,surfacelittershouldbeclearedfirst,followedbytherandomcollectionofasoil/sedimentsamplefrom0cmto15cmusingasamplingshovel.Relevantparameterscanthenbedeterminedthroughphysicalorchemicalmethodsinthelaboratory.

Thewaterqualitysurveyprimarilyfocusesonkeyindicatorssuchasturbidity,dissolvedoxygen,pH,organiccarbon,ammoniumsalts,nitrates,nitrites,andactivephosphates.Thisassessmentsurveycanbeconductedconcurrentlywiththeplantcommunityplotsurvey,withthemethodologyforeachindicatorfollowingrelevanttechnicalstandards.

Thehydrologicalenvironmentsurveyemphasizesparameterssuchastemperature,salinity,tidalcurrents,andwaves.Likethewaterqualitysurvey,itcanbecarriedoutinparallelwiththeplantcommunityplotsurvey,witheachfactor's

HandbookofEcosystemRestorationforCoastalHazardMitigation:CoastalSaltMarshes

methoddeterminedaccordingtotheapplicabletechnicalstandards.

Topographicandgeomorphologicalsurveysassessindicatorsincludingwaterdepth,elevation,andgeomorphologicalunits.Thesesurveysshouldcoverrepresentativeareasonthesectionandcanbeconductedalongsidetheplantcommunityplotsurvey.Attentionshouldbegiventomeasuringtheelevationatthecenteroftheplantcommunityplotduringthesurvey.

5.3.4BiologicalCommunities

Thesurveyofmacrobenthiccommunitiescanbeconductedconcurrentlywiththeplantcommunitysampleplotsurvey.Thissurveyshouldincluderecordingthespecies,quantity,andbiomassofmacrobenthosineachquadrat.Birdsurveysshoulddocumentspeciesandquantity,withsurveytimingbasedonlocalphenologicalcharacteristics.

5.3.5ThreatFactors

Thesurveyofnaturalthreatfactorsshouldgatherinformationonnaturalelementsthatjeopardizethedistributionanddevelopmentofcoastalsaltmarshesinthesurveyedarea.CommonnaturalthreatfactorsinChina’scoastalzonesmainlyincludetyphoons,stormsurges,floods,sea-levelrise,coastalerosion,andothermarinedisasters.Thissurveyshouldnoteifthesurveyareahasexperiencedmarinedisastersandrecorddetailssuchasfrequency,intensity,andassociatedlosses.

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HandbookofEcosystemRestorationforCoastalHazardMitigation:CoastalSaltMarshes

16

Anthropogenicfactorsshouldfocusonactivitiessuchascoastalengineering,mariculture,fishing,seawaterpollution,utilizationofsurroundingresources,tourismdevelopment,andtheinvasionofalienspecies.Informationcanbegatheredthroughvariousmeansincludingdatacollection,on-sitesurveys,andsocialsurveys.

5.3.6DisasterPreventionandMitigationFunction

Researchandfieldobservationshavehighlightedthesignificantroleofcoastalsaltmarshesinpreventingandmitigatingoceandynamicdisastersbyattenuatingwavesandcurrents.Theeffectivenessofcoastalsaltmarshesinreducingmarinedisastersisoftenmeasuredbytheirwaveattenuationcapacity(whichreferstothereductioninwaveheightafterpassingthroughacertainwidthofcoastalsaltmarsh).

HandbookofEcosystemRestorationforCoastalHazardMitigation:CoastalSaltMarshes

Assessingthedisastermitigationcapacityofcoastalsaltmarshestypicallyreliesonfieldsurveydata.Thefieldsurveymethodforassessingthiscapacityusuallyinvolvescross-sectionalobservations.Thesecross-sectionsshouldideallybeparalleltothedirectionofincomingwaves(typicallyperpendiculartothecoastlinedirection)andselectedtorepresentthecharacteristicsoftheentiresaltmarshregion.Inareaswithsignificantvariationsinsaltmarshcharacteristics,multiplecross-sectionsshouldbechosen.Eachcross-sectionshouldhavetypicalstations,withatleasttwostationspercross-section—oneattheseawardedge(seawardpoint)andoneatthelandwardedge(landwardpoint)ofthesaltmarshdistributionarea.Thesestationsshouldobservewaveheightandwaterlevelatbothseawardandlandwardpoints.Whenselectingobservationperiods,suchasduringtyphoonsandstormsurges,theentiredurationofthedisasterimpactshouldbeconsideredasmuchaspossible(refert