景观生态.docx

景观生态.docx

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景观生态

Ecologists,Farmers,Tourists-GISSupportPlanningofRedStonePark,China

（Thispaperisprintedfrom:

GeographicInformationResearch：

BridgingtheAtlantic（Craglia,M.andHellen,C.Eds.）Tayor&Francis.pp.480-494.1997

ABSTRACT:

Landscapeplanningisconsideredasaprocedureofdefensetakingplaceamongdefendersofvariousprocesses.Defendingbysecuritypatterns（SPs）--strategicportionsandpositions--maysignificantlyincreasetheefficiencyofsafeguardingtheprocessesofourconcern.SPsaredefinedandidentifiedbasedonthethreshold-typequalityofthedynamicsoftheprocesses.AlternativechangemodelsareproposedbasedonSPs.DecisionmakingbasedonSPsisalsodiscussed.TheSPapproachisillustratedbythecasestudyoftheRedStoneNationalPark,China,inwhichadefendingprocedureamongecologists（defendersofecologicalprocesses）,tourists（defendersofvisualperceptualprocesses）andfarmers（defendersofagriculturalconversionprocesses）issimulated.IntegratedwiththeSPapproach,GISshowsgreatpotentialforsupportingdecisionmakinginlandscapechanges.

INTRODUCTIONSECURITYPATTERNSANDSPAPPROACH

Landscapeplanningisconsideredaprocedureofdefenseinvolvingdefendersofvariousprocesses.Howcanwedefendtheprocessesofourconcernmoreeffectivelywhilemaximisingopportunitiesforchanges?

Thispapertriestoanswerthisquestionusingtheconceptofsecuritypatterns（SPs）anddemonstrateshowGIScanbecombinedwiththeSPapproachinlandscapeplanning.

Bydefinition,SPsarethespatialpatternscomposedofstrategicportions,positions,criticalscales（sizes）,numbers,shapesandinter-relationshipsthatareassociatedwithcertainthresholdsinthenon-lineardynamicsofprocessesinthelandscapes.SPshaveorpotentiallyhaveacriticalsignificanceinsafeguardingcertainprocesses,e.g.theprocessofspeciesdispersal,spreadoffireandotherdisturbances,visualperceptionandpreference,agriculturalconversion,etc.

Intermsoftheirsignificancefortheprocessesofourconcern,securitylandscapecomponentshavethreebasiccharacteristics:

（i）Initiative,thequalityofaportionorpositionwhoseoccupationislikelytogiveittheadvantageofinitiatingcertainprocesses;

（ii）Efficiency,thequalityofapositionorportionwhoseoccupationwillgiveittheadvantageoflesscostinenergyandmaterialsandbemuchmoreeffectiveinpromotingorcontrollingcertainprocesses;

（iii）Co-ordination,thequalityofapositionorportionwhoseoccupationwillgiveittheadvantageofeffectivespatialcommunicationamongneighboringelements.

SPsaremulti-leveled.Eachindividualprocessinthelandscapehasitsownsecuritypatterns（Figure1）,andtheseindividualSPsmaycompeteandoverlapspatially.

Furthermore,eachindividualprocesshasSPsatvarioussecuritylevels.

Figure1Apresumedhierarchyoflandscapesecuritypatterns

TheconceptofSPsisbasedontwoassumptionsconcerningspatialpatternsandprocesses:

（a）landscapepatternseffectprocesses,and（b）therearestrategiclandscapesassociatedwithsomethresholdsinthedynamicsofcertainprocesses.

Numerousobservationssuggestthatthespatialpatternsofalandscapeinfluencevariousecologicalprocessessuchasspeciesdispersalandpopulationdynamics（FormanandGodron,1986;Turner,1989）;humanprocessessuchasresidentialdevelopmentanddemographicdynamics（e.g.BerryandHorton,1970）,andvisualperceptualprocesses（Gibson,1950;Lynch,1960）.

Notallportionsandpositionsofthelandscapeareequallyimportantintermsoftheirinfluenceonindividualprocesses,somearemoreimportantthanothers,andsomearestrategicallycritical.Examplesofsuchstrategicportionsandpositionsincludetheinletsandoutletsofabasinandbreaksinacorridorthathavecriticalvaluesforecologicalprocesses（FormanandGodron,1986;Merriam,1984）;theconspicuouslandmarks,narrowdefiles,gorgesandbridgesthathavesignificantvisualperceptualeffects（SteinandNiederland,1989;Tuan,1974）;aswellascertainplacesthathaveastrategicsignificanceforeconomicprocesses（TaaffeandGauthier,1973）.

Itisimportanttonote,however,thatinsomecasesvariousprocessesinthelandscapemaybecontrolledbyspatialpatternsthatarenotintuitivelyobviousnorvisuallyapparenttoahumanobserver.Itisassumedthatsomekindsofthresholdsexistinthetrajectoriesofthedynamicsofprocesses.Atsomepoints（intermsofnumber,size,shapeandinter-distanceoflandscapeelements）,aslightchangeinlandscapepropertyproducessuddenchangesintheresponseoftheprocess.Suchthresholdshavebeenrecognizedinurbandevelopment（Kozlowski,1986）.Similartothresholds,otherconceptshavebeenproposedthatmayalsobeusefulinunderstandingmyideasconcerningthestrategiclandscapeandsecuritypatternssuchassafeminimumstandards（SMS）（Bishop,Fullerton,etal,1974;Ciriacy-Wantrup,1968）,carryingcapacity,andultimateenvironmentalthresholds（UETs）（KozlowskiandHill,1993）,etc.

Itisthusreasonabletoassumethat:

（1）landscapepatternsassociatedwiththesecriticalthresholdsorconstraintsarelikelytobestrategicallycriticalincontrollingorpromotingcertainprocesses;

（2）landscapedesignandmanagementfollowingthesestrategicallycriticalpatternscanmoreeffectivelysafeguardorcontroltheprocesses.

Therefore,itisworthwhiletoidentifyandapplySPsinlandscapeplanning.Thefollowingtwoaspectsofexplorationbecomethemajorfocusofthispaper:

（1）HowcanwedefineandidentifySPsandwhatarethey?

（2）HowcanweapplySPsinlandscapeplanningtoachievealessdetrimentallandscape,whileatthesametime,maximallymakingchangesacceptabletodecisionmakersand/ordevelopers?

ThesetwoaspectsofinquirycomposeanapproachtolandscapeplanningwhichIcalltheSPapproach,ortheapproachofsecuritypatterns.Itisanapproachtodefendingvariousprocessesofourconcern,aimingatagoodbalanceofacceptablechangesandasecurerlandscapethroughidentifyingandapplyingsecuritypatterns（SPs）.TheSPapproachtriestoestablish'stopsigns'intheproceduresofdecisionmakingforvariouslandscapechanges,andtosafeguardthesecurityoftheprocessesatcriticalpoints.Inacertainsense,definingSPsisastrategyofspatialdefense,anoperationalweaponofnegotiationaimedatalessharmfulchangebycontrollingcriticalpoints,or'frontiers'.DefensebytheseSPsisexpectedtobemoreeffectiveinsafeguardingthelandscapeprocessesofourconcern.GIShasgreatpotentialwhencombinedwiththeSPapproachinlandscapeplanninganddecisionmaking（seeYu,1995cformoredetaileddiscussionontheSPconcept）.

AcasestudyoftheRedStoneNationalParkinsouthChina,isusedtoillustratetheSPapproach.Thiscaseisselectedsinceitdramaticallyrepresentsadefensibleprocedureoflandscapechangeamongdefendersofthreeinteracting,andoftencompeting,processesinlandscapes,includingecological,visualandagriculturalconversionprocesses.

DEFENDINGTHESECURITYOFPROCESSESINREDSTONENATIONALPARK:

ACASESTUDY

RedStoneNationalParkis313squarekilometersinsize（Figure2）.Thedominantregionalnaturalvegetationiscomposedofsub-tropical

Figure2ThelandscapeoftheRedStoneNationalParkinSouthChina

evergreenforestswhichhavebeenseriouslydestroyedattheperipheralareawithsomeisolatedremnantpatchesscatteredintheremoteareas.Thelandscapeismadeupofhundredsofheavilyerodedrockyhills,squarewithflattopandsteepslopes.Thisuniquelandformistheprimaryfactoraffectingthedistributionofsoil,vegetation,wildlifehabitats,visualqualityandagriculture.Theremnantbiologicalislandsareextremelyvaluableintermsofbiodiversityconservationandlandscaperestoration.Thevisualqualityisextraordinary.ItisoneofthemajortouristattractionsinsouthChina.Thefertilesoilandsub-tropicalclimatemakethislandoneofthemostproductiveagriculturalareas.Abouttwentythousandfarmersliveinseventyvillagesscatteredinthesmallalluvialplanesinthishillylandscape.Theproblemsthisnationalparknowfacesaretypicalofothernationalprotectedareas,namely,theconflictsbetweendevelopment,ecologicalandvisualconservation.Landscapeplanninginthisparkisadefensibleproceduredramaticallytakingplaceamongdefendersofvariousprocesses.Asaresult,thiscasestudyaanillustrativeexamplefortheSPapproach.

Threeprocessesareconcernedinthiscasestudy:

ecological,visualperceptual,andagricultural.TheobjectivesinthiscasestudyaretoexploreaneffectivewayofdefendingvariouslandscapeprocessesinthisnationalparkbyidentifyingandapplyingSPs,andtodemonstratehowGIScanbeintegratedintothedefensibleprocedureoflandscapechangeanddecisionmaking.

SecuritypatternsintheRedStoneNationalPark

EcologicalSPs:

Ecologists'DefensiveFrontiers

Ecologicalprocessesconcernedinthiscasearespeciesdispersalandmaintenance.Threegroupsofspeciesaretargeted:

medium-sizedmammals（CervidaeandViverridaefamilies）,pheasants（Phasianidaefamily）andamphibians（CryptobranchidaeandRanidaefamilies）.Thesespeciesarenativetothisregionandhaveanendangeredstatus.EcologicalSPsareidentifiedbyanalyzingaccessibilitysurfacethatrepresentthepotentialcoveragebythespeciesofourconcern.

Accessibilitysurfacesaredevelopedusingaminimumcumulativeresistance（MCR）model（Knaapen,SchefferandHarms,1992;Yu,1995b）,thismodelconceivesthedynamicsofspeciesdispersalasafunctionofsources,distanceandintermediatelandscapes.Nativehabitatsofthetargetspe