景观生态学原理在空间规划中的应用

LandscapeEcologyPrincipleInSpatialPlanningAnurgentneedexistsfornewtoolsandnewlanguagetounderstandhowtolivewithoutlosingnature.Thesolutionwillbeatthelandscapescale----workingwiththelargepattern,understandinghowitworks,anddesigninginharmonywiththestructureofthenaturalsystemthatsustainsusall.Designersandplannersmustweavertogetherthismosaicofpatchesandcorridornetworks,likeaquiltheldtogetherwiththreads,toholdthelandscapefromfallingapart.Ithelpsreducethelandscapefragmentationanddegradationsoevidentaroundus.TimechangesHistoryindicatesthatinthefaceofcrisis,humaningenuity,creativity,discoveries,inventions,andnewsolutionscascadeforth.Todayalmostallmajorstudiespointtoacoalescenceinthenextfewdecadesofsignificantlanddegradation,populationgrowth,watershortage,fertilesoilerosion,biodiversityloss,andspreadofhugeurbanareas.Societyiscomfortableinthinkingofsmallspacesandshorttimes,oratbestconsideringtrendsseparately.Whenthetrendsareconnected,itishardtomissthecrisislooming.Thetimetablesaysweandourchildrenwillbethere.Atcenterstagewillbeland-usepattern.

Landplannersandlandscapearchitectsare

uniquelypoisedtoplaykeyrolesforsociety,toprovidenewsolutions.Theseareprofessionalsandscholarswhofocusontheland.Solveproblems.Designandcreateplans.Looktothefuture.Areoptimists,can-dopeople.Aresynthesizerswhoweavediverseneedstogetherintoawhole.Haveingenuityandcreativity.Knowaestheticsoreconomics.Knowthathumancultureisessentialinadesignorplan.Andknowthatecologicalintegrityofthelandiscritical.

Landscapearchitectureandland-useplanninghavealonganddistinguishedhistoryofinspiredaccomplishments.TheimagesofextensiveItaliancountryvillas,19th-centuryplanninganddesignofmajorAmericancities,andthe20th-centurydevelopmentofnationalparksareimpressiveharmoniesintheland.Akeytotheirbrillianceistheenlightenedmeshingofnatureandculture.Thedesignersandplannerswerenotamateursineithernatureorculture,buthadextensiveeducationandknowledgeinboth.Natureincludedthebiologicalpatternsandphysicalprocessesentwined(缠)invegetation,wildlifepopulations,speciesrichness,wind,water,wet-lands,andaquaticcommunities.Cultureintegratedthediversehumandimensionsofeconomics,aesthetics,communitysocialpatterns,recreation,transportation,andsewage/wastehandling.Whatarethenaturalfeatureswhichmakeatownshiphandsome?Ariver,withitswaterfallsandmeadows,alake,ahill,aclifforindividualrocks,aforest,andancienttreesstandingsingly.Suchthingsarebeautiful;theyhareahighusewhichneverpresent.Iftheinhabitantsofatownwerewise,topreservethesethings,thoughataconsiderableexpense;forsuchthingseducatefarmorethananyhiredteachersorpreachers,oranypresentrecognizedsystemofschooleducation.Idonotthinkhimfittobethefounderofastateorevenofatownswhodesnotforeseetheuseofthesethings....

HenryDavidThoreau,journal,1861Insomecountriesthesetwobasiccomponents-ecologyandculture–havedivergedrelativelyrecently.Forexample,ecologyhasmatured,andveered(转向)awayfromplanninganddesign.Oreconomicshasbecomeparamount.Oraesthetics.Orsewageandwasteshavebeenconsideredonlyanengineeringproblem.Orflourishinglitigation(诉讼)hascoloreddecision-making.Orlocalactionshaveoverriddenregionalthinkingandplanning.Thesesoundsofamiliartoprofessionalsinthefield.Thedeepermessageistheimportanceofanewformoflinkagebetweenecologyandculture,landandpeople,natureandhumans.Thereisanincreasingevidencesuggestingthatmentalhealthandemotionalstabilityofpopulationsmaybeprofoundlyinfluencedbyfrustratingaspectsofanurban,biologicallyartificialenvironment.Itseemslikelythatwearegeneticallyprogrammedtoanaturalhabitatofcleanairandavariedgreenlandscape,likeanyothermammal.Thespecificphysiologicalreactionstonaturalbeautyanddiversity,totheshapesandcolorsofnature,especiallytogreen,tothemotionsandsoundsofotheranimals,wedonotcomprehendandarereluctanttoincludeinstudiesofenvironmentalquality.Yetitisevidentthatinourdailylivesnaturemustbethoughtofnotasaluxurytobemadeavailableifpossible,butaspartofourinherentindispensablebiologicalneed.

FrederickLawOlmsted,inBiography,byJ.E.Todd,1982.Themissingingredientandkeytothenewweavingappearedinthe1980s,andmushroomedinthe1990s.Landscapeecology,theecologyoflargeheterogeneousareas,oflandscapes,ofregions,ofportionsthereof,orsimplyoflandmosaics,hasincreasinglyappearedonthepalette.Itisatexactlytherightspatialscale.Itexplicitlyintegratesnatureandhumans.Itsprinciplesworkinanylandscape,fromurbantopasturelandanddeserttotundra.Itsspatiallanguageissimple,catalyzingreadycommunicationamongland-usedecision-makers,professionals,andscholarsofmanydisciplines.Anditisnoacademicmusing(沉思的),butcenteredonspatialpattern,iseasilyanddirectlyusable.Itoftenevokes,“whydidn’twethinkofthat?”or“Goodtoknowthere’ssciencebehinditnow.”Landscapearchitectsandland-useplannerswillalwaysbeexpertsinareas,thetinyparks,housingclusters,andshoppingmalls.Atthesametime,suchprofessionalalsoknowonlydesigningandplanninglittlepiecesofthelandleadstoafragmentedworldthatdoesn’twork,eitherecologicallyorforpeople.Fortunately,theknowledgeablemeshingofhumansandecologyatabroaderscaleisnowintherepertories,andwillbecomeroutine.Thesolutionforasmalleconomicallyoraestheticallyfocusedprojectwillemanateasmuchfrom（来自）thesurroundingmosaicpatternasfromthesiteitself.Andthelargerland-areaprojectwillfocusdirectlyonspatialpattern,movements,andchangesofitsmosaic,basedsolidlyonprincipleoflandscapeandregionalecology.DevelopmentoflandscapeecologyThefoundationsoflandscapeecologymaybetracedbacktoscholarsuptoabout1950,whoelucidatedthenaturalhistoryandphysicalenvironmentpatternoflargeareas.Form1950to1980diverseimportantthreadsemerged,andtheirweavingtogethercommenced.Thetermlandscapeecologywasusedwhenaerialphotographybegantobewidelyavailable.Theconceptfocusedonspecificspatialpatterninasectionofalandscape,wherebiologicalcommunitiesinteractedwiththephysicalenvironment(Troll,1939,1968).Diversedefinitionsofthetermofcoursehaveappearedovertheyears,buttodaytheprimary,mostwidelyheldconceptisasfollows.Ecologyisgenerallydefinedasthestudyoftheinteractionsamongorganismsandtheirenvironment,andalandscapeiskilometers-widemosaicoverwhichparticularlocalecosystemsandland-usesrecur.Theseconceptshaveproventobebothsimpleandoperationallyuseful.Thuslandscapeecologyissimplytheecologyoflandscapes,andregionalecology，theecologyofregions.Severalotherdisciplinesorimportantconceptswereincorporatedduringthisweavingphaseoflandscapeecology.Theecosystemconcept,animalandplantgeography,vegetationmethodology,hedgerowstudies,agronomicstudies,andislandbiogeographictheorywereimportant.Alsoquantitativegeography,regionalstudies,humancultureandaesthetics,andlandevaluationwereincorporated.Landscapearchitectureandland-useplanningliteraturebegantobeincluded.Thisphaseproducedanabundanceofintriguing(迷人的),interdisciplinaryindividualdesigns,butnoclearformoftheoveralltapestry(织锦)wasevident.Sinceaboutl980the“1andmosaic”phasehas

coalesced(接合),wherepuzzlepiecesincreasinglyfittogetherandanoverallconceptualdesignoflandscapeandregionalecologyemerges.Editedbookstendtocompiledisparate,butsometimeskey,piecesoflandscapeecology.Theseincludegeneralconcepts,habitatfragmentationandconservation,corridorsandconnectivity,quantitativemethodology,andheterogeneity,boundaries,andrestoration.Themajorauthoredvolumes,incontrast,tendtointegrateandsynthesizetheoryandconcepts.Thesebooksincludelandevaluationandplanning(Zonneveld1979,Takeuchi1991),soilandagriculture(Vink1980),loggingandconservation(Harris1984),totalhumanecosystem(Naveh&Lieberman1993),hierarchytheory(O’Neilletal.1986),statisticalmethodology(Jongmanetal.1987),rivercorridors(Malanson1993),andlandmosaics(Forman&Godron1986,Forman1995).Ofcourse,togainasolidandfullunderstandingofthesubject,articlesinLandscapeEcologyandmanyotherjournalsareamust,andoftenadelight.Landscapeecologytoday

Theprinciplesoflandscapeandregionalecologyapplyinanylandmosaic,fromsuburbantoagricultureanddeserttoforest.Theyworkequallyinpristinenaturalareasandareasofintensehumanactivity.Theobjectspreadoutbeneathanairplane,orinanaerialphotograph,containslivingorganismsinabundance,andthereforeisalivingsystem.Likeaplantcellorahumanbody,thislivingsystemexhibitsthreebroadcharacteristics:structure,functioning,andchange.landscapestructureisthespatialpatternorarrangementoflandscapeelements.Functioningisthemovementandflowofanimals,plants,water,wind,materials,andenergythroughthestructure.Changeisthedynamicsoralterationinspatialpatternandfunctioningovertime.Thestructuralpatternofalandscapeorregioniscomposedentirelyofthreetypesofelements.Indeed,theseuniversalelements-patches,corridors,andmatrix----arethehandleforcomparinghighlydissimilarlandscapeandfordevelopinggeneralprinciples.Theyalsoarethehandleforland-useplanningandlandscapearchitecture,sincespatialpatternstronglycontrolsmovements,flows,andchanges.Thesimplespatiallanguagebecomesevidentwhenconsideringhowpatches,corridors,andthematrixcombinetoformthevarietyoflandmosaicsonearth.Whatarethekeyattributesofpatches?Theyarelargeorsmall,roundorelongated,smoothorconvoluted,fewornumerous,dispersedorclustered,andsoforth.Whataboutcorridors?Theyappearnarroworwide,straightorcurvy,continuousordisconnected,andsoon.Andthematrixissingleorsubdivided,variegated(多样化的)ornearlyhomogeneous,continuousorperforated(穿透的),etc.Thesespatialattributesordescriptorsareclosetodictionarydefinitions,andallarefamiliartodecision-makers,professionals,andscholarsofmanydisciplines.Thewholelandscapeorregionisamosaic,butthelocalneighborhoodislikewiseaconfigurationofpatches,corridors,andmatrix.Landscapeecologistsareactivelystudyinganddevelopingprinciplesforthebiodiversitypatternsandnaturalprocessesintheseconfigurationsorneighborhoodmosaics.Forexample,changingamosaicbyaddinga

hedgerow,pond,house,woods,road,orotherelementchangesthefunctioning.Animalschangetheirroutes,waterflowsalterdirection,erosionofsoilparticleschanges,andhumansmovedifferently.Removinganelementaltersflowsinadifferentmanner.Andrearrangingtheexistingelementscausesyetgreaterchangesinhowtheneighborhoodfunctions.Thesespatialelementsandtheirarrangementsarethereadyhandlesforlandscapearchitectsandland-useplanners.Naturalprocessesaswellashumanactivitieschangelandscapes.Inatimeseriesofaerialphotographsasequenceofmosaicstypicallyappears.Habitatfragmentationisfrequentlynotedanddecried.Butmanyotherspatialprocessesareevidentinlandtransformation,suchasperforation,dissection,shrinkage,attrition,andcoalescence,eachwithmajorecologicalandhumanimplications.Inshort,thelandscapeecologyprinciplesinthisbookaredirectlyapplicableandofferopportunitiesforwiseplanning,design,conservation,management,andlandpolicy.Theprinciplesaresignificantfromneighborhoodtoregionalmosaics.Theyfocusonspatialpattern,whichstronglydeterminesfunctioningandchange.Theirpatch-corridor-matrixcomponentshaveuniversalityforanyregion.Andtheirlanguageenhancescommunicationandcollaboration.Theywillbecomecentralassocietybeginstoseriouslyaddresstheissueofcreatingsustainableenvironments.Roadmap

PartIpresentsthelandscapeecologicalprinciples.Forconveniencethesearegroupedbypatches,edges,corridors,andmosaics.PartIIthenillustratespracticalapplicationsoftheprinciple.Thisbeginswithschematicapplicationsatbroad,mediumandfinescales.Itendswithencapsulatedcasestudiesfromaroundtheworld.PartOne:Principles

PATCHESLandscapeecologyprinciplesarelistedandillustratedinfoursections:Patches;Edges;Corridors;

Mosaics.Eachsectionbeginswithanintroductiontoimportanttermsandconcepts,andendswithalistofkeyreferences.Inadenselypopulatedworldplantandanimal

habitatincreasinglyappearsinscatteredpatches.Ecologistsfirstconsideredhabitatpatchesanalogouswithislands,butsoonlargelyabandonedtheanalogyduetothemajordifferencesbetweentheseaandthematrixofcountrysideandsuburbandevelopmentssurroundinga“terrestrial”patch.Patches,however,doexhibitadegreeofisolation,theeffectandseveritybeingdependentonthespeciespresent.Fouroriginsorcausesofvegetationpatchesareusefullyrecognized:remnants(e.g.,areasremainingfromanearliermoreextensivetype,suchaswoodlotsinagriculturalareas);introduced(e.g..anewsuburbandevelopmentinanagriculturalare,orasmallpasturewithinaforest);disturbance(e.g..aburnedareainaforest.oraspotdevastatedbyaseverewindstorm):andenvironmentalresources(e.g.,wetlandsinacity,oroasesinadesert).Patchesareanalyzedanddifferentiatedintermsof(1)size,(2)number,and(3)location.Patchesmaybeaslargeasanationalforest,orassmallasasingletree.Patchesmaybenumerousinalandscape.Suchasavalanchesorrockslidesonamountainside,orbescarcesuchasoasesinadesert.Thelocationofpatchesmaybebeneficialordeleterioustotheoptionalfunctioningofalandscape.Small,remnantforestpatchesbetweenlargereservesinanagriculturalmatrixcanhebeneficial.Incontrast,alandfilllocatedadjacenttoasensitivewetlandmayhaveanegativeimpactontheecologicalhealthofthelandscape.Patchsize:largeorsmall?Pl.Edgehabitatandspecies

Dividingalargepatchintotwosmalleronescreatesadditionaledgehabitat,leadingtohigherpopulationsizesandaslightlygreater

numberofedgespecies,whichareoftencommonorwidespreadinthelandscape.P2.Interiorhabitatandspecies

Dividingalargepatchintotwosmalleronesremovesinteriorhabitat,leadingtoreducedpopulationsizesandnumberofinteriorspecies,whichareoftenofconservationimportance.P3.Localextinctionprobability

Alargerpatchnormallyhasalargerpopulationsizeforagivenspeciesthanasmallerpatch,makingitlesslikelythatthespecies(whichfluctuatesinpopulationsize)willgolocallyextinctinthelargerpatch.P4.Extinction

Theprobabilityofaspeciesbecominglocally

extinctisgreaterifapatchissmall,oroflow

habitatquality.P5.Habitatdiversity

Alargepatchislikelytohavemorehabitatspresent,andthereforecontainagreaternumberofspeciesthanasmallpatch.

P6.Barriertodisturbance

Dividingalargepatchintotwosmaller

onescreatesaharriertothespreadofsome

disturbances.

P7.Largepatchbenefits

LargePatchesofnaturalvegetationaretheonlystructuresinalandscapethatprotectaquifersandinter-connectedstreaminnetworks,sustainviablepopulationsofmostinteriorspecies,providecorehabitatandescapecoverformostlarge—home—rangevertebrates,andpermitnear—naturaldisturbanceregimes.

P8.Smallpatchbenefits

SmallPatchesthatinterruptextensive

stretchesofmatrixact

assteppingstonesforspeciesmovement.Theyalsocontainsomeuncommonspecies

where1argepatchesareabsentor,inunusualcases,areunsuitableforaspecies.Thereforesmallpatchesprovidedifferentandsupplementalecologicalbenefitsthanlargepatches.

PatchNumber:HowMany?P9.HabitatLoss

Removalofapatchcauseshabitatloss,whichoftenreducesthepopulationsize

ofaspeciesdependentuponthathabitattype,andmayalsoreducehabitatdiversity,leadingtofewerspecies.

P10.Metapopulationdynamics

Removalofapatchreducesthesizeofametapopulation(i.e..aninteractingpopulationsubdividedamongdifferentpatches),therebyincreasingtheprobabilityoflocalwithin—patchextinctions,slowingdowntherecolonizationprocess,andreducingstabilityofthemetapopulation.

P11.NumberofLargepatches

Whereonelargepatchcontainsalmostallthespeciesforthatpatchtypeinthelandscape,twolargepatchesconsideredtheminimumformaintainingspeciesrichness.However.whereonepatchcontainsalimitedportionofthespeciespool,uptofourorfivelargepatchesareprobablyrequired.

P12.GroupedpatchesashabitatSomerelativelygeneralistspeciescan,intheabsenceofalargepatch,surviveinanumberofnearbysmallerpatches,whichalthoughindividuallyinadequate,aretogethersuitable.

P13.Extinction

Theprobabilityofaspeciesgoinglocallyextinctisgreaterinanisolatedpatch.Isolationisafunctionnotonlyofthedistance,butalsoofthecharacteristics(i.e.,resistance)oftheinterveningmatrixhabitat.

P14.Recolonization

Apatchlocatedincloseproximitytoother

patchesorthe“mainland”willhaveahigher

chanceofbeing(re-)colonizedwithin

atimeinterval,thanamoreisolatedpatch.

P15.PatchselectionforconservationTheselectionofpatchesforconservationshouldbebasedontheir:1)contributiontotheoverallsystem.i.e.,howwellthelocationofapatchrelatesorlinkstootherpatcheswithinthelandscapeorregion;and2)unusualordistinctivecharacteristics,

e.g..whetherapatchhasanyrare,threatened,orendemicspeciespresent.

EDGESANDBOUNDARIESEdge

:theouterportionofapatchwheretheenvironmentdifferssignificantlyfromtheinteriorofthepatch.Edgeandinteriorenvironmentssimplylookandfeeldifferently.verticalandhorizontalstructure,width,andspecies

compositionandabundance,intheedgeofapatch,differfrominteriorconditions,andtogethercomprisetheedgeeffect.Whetheraboundaryiscurvilinearorstraightinfluencestheflowofnutrients,water,energy,orspeciesalongoracrossit.

Boundariesmayalsobe“political”or“administrative”thatisartificialdivisionsbetweeninsideandout,whichmayormaynotcorrespondtonatural“ecological”boundariesoredges.Relatingtheseartificialedgeswithnaturalonesisimportantashumandevelopmentcontinuesitsexpansionintonaturalenvironments.Theedgescreatedwillincreasinglyformthecriticalpointforinteractionsbetweenhuman-madeandnaturalhabitats.

Theshapesofpatches,asdefinedbytheirboundaries,canbemanipulatedbylandscapearchitectsandland-useplannerstoaccomplishanecologicalfunctionorobjective.Duetothediversesignificanceofedges,richopportunitiesexisttousethiskeyecologicaltransitionzonebetweentwotypesofhabitatindesignsandplans.

El.Edgestructuraldiversity

Vegetativeedges

withahighstructuraldiversity,verticallyorhorizontallyarericherinedgeanimalspecies.

E2.Edgewidth

Edgewidthdiffersaroundapatch,withwideredgesonsidesfacingthepredominantwinddirectionandsolarexposure.

E3.Administrativeandnaturalecologicalboundary

Wheretheadministrativeorpoliticalboundaryofaprotectedareadoesnotcoincidewithanaturalecologicalboundary,theareabetweentheboundariesoften

becomesdistinctive,andmayactasa

bufferzone,reducingtheinfluenceofthesurroundingsontheinterioroftheprotectedarea.

E4.Edgeasfilter

Patchedgesnormallyfunctionasfilters,which

dampen(使潮湿，减弱)influencesofthesurroundingsonthepatchinterior.

E5.Edgeabruptness

Increased

edgeabruptnesstends

increasemovementalonganedge,whereaslessedge

abruptnessfavorsmovementacrossanedge.

E6.Naturalandhumanedges

Mostnaturaledgesarecurvilinear,complex,andsoft,whereashumanstendtomakestraight,simple,andhardedges.

E7.StraightandcurvilinearboundariesAstraightboundarytendstohavemore

speciesmovementalongit,whereasa

convolutedboundaryismorelikelytohave

movementacrossit.

E8.Hardandsoftboundaries

Comparedwithastraightboundarybetweentwoareas,acurvilinear“tiny-patch’’boundarymayprovideanumberofecologicalbenefits,includinglesssoilerosionandgreaterwildlifeusage.

E9.EdgecurvilinearityandwidthCurvilinearityandwidthofanedgecombinetodeterminethetotalamountofedgehabitatwithinalandscape.

E10.Coves(内凹)andLobes(圆形突出物)

Thepresenceofcovesandlobesalonganedgeprovidesgreaterhabitatdiversitythanalongastraightedge,therebyencouraginghigherspeciesdiversity.

E11.Edgeandinteriorspecies

Amoreconvolutedpatchwillhaveahigher

proportionofedgehabitat,therebyslightlyincreasingthenumberofedgespecies.

butsharplydecreasingthenumberofinteriorspecies,includingthoseofconservationimportance.

E12.Interactionwithsurroundings

Themoreconvolutedtheshapeofapatch,the

more

interaction,whetherpositiveornegative,thereisbetweenthepatchandthesurroundingmatrix.

E13.Ecologically“optimum”patchshapeAnecologicallyoptimumpatchprovidesseveralecologicalbenefits,andisgenerally“spaceshipshaped,”witharoundedcoreforprotectionofresources,plussomecurvilinearboundariesandafewfingersforspeciesdispersal.

E14.Shapeandorientation

Apatchorientedwithitslongaxisparalleltotherouteofdispersing

individualswillhavealowerprobabilityofbeing(re-)colonized,thanapatchperpendicularto

therouteofdispersers

CORRIDORSANDCONNECTIVITYThelossandisolationofhabitatisaseeminglyunstoppableprocessoccurringthroughoutthemodernworld.Landscapeplannersandecologistsmustcontend(竞争)withthiscontinuingprocessiffurtherreductionsin

biodiversityaretobeslowedorhalted.Severalkeyspatialdynamicprocessescausethisisolation:Fragmentation(i.e.,breakingupalarger/intact

habitatintosmallerdispersedpatches);Dissection(i.e.,splittinganintacthabitatintotwopatchesseparatelybyacorridor);Perforation(i.e.,creating“holes”withinanessentiallyintacthabitat):Shrinkage(i.e.,thedecreaseinsizeofoneormorehabitats);Attrition(i.e..thedisappearanceofoneormorehabitatpatches).Inthefaceofcontinuedhabitatlossandisolation,manylandscapeecologistsstresstheneedforprovidinglandscapeconnectivity,particularlyintheformsofwildlifemovementcorridorsandsteppingstones.Despiteresidualdiscussionovertheeffectivenessofcorridorsinenhancingbiodiversity,agrowingempiricalbodyofresearchunderlinesthepositivenetbenefitsaccruing(增加,产生)fromincorporatinghigherqualitylinkagesbetweenhabitatpatches.Corridorinthelandscapemayalsoactasbarriersorfilterstospeciesmovement.Somemaybepopulation“sinks”(i.e.,isolationwhereindividualofaspeciestendtodecreaseinnumber).Forexample,roadways,railroads,powerlines,canals,andtrails,maybethoughtofas“troughs”(槽,水槽)orbarriers.Finally,streamorriversystemsarecorridorsofexceptionalsignificanceinalandscape.Maintainingtheirecologicalintegrityinthefaceofintensehumanuseisbothachallengeandanopportunitytolandscapedesignersandland-useplanners.Cl.ControlsoncorridorfunctionsWidthandconnectivityaretheprimarycontrolsonthe

fivemajorfunctionsofcorridors,i.e.,habitat,conduit(管道,导管),filter,source,andsink.

C2.Corridorgapeffectiveness

Theeffectofagapinacorridoronmovementofaspeciesdependsonlengthofthegaprelativetothescaleofspeciesmovement,andcontrastbetweenthecorridorandthegap.

C3.Structuralversusfloristic(花的,植物的)SimilaritySimilarityinvegetationstructureandfloristics(plantspecies)betweencorridorsandlarge

patchesispreferable,thoughsimilarityinstructurealoneisprobablyadequateinmostcasesforinteriorspeciesmovementbetweenlargepatches.

C4.Steppingstoneconnectivity

Anewofsteppingstones(smallpatches)isintermediateinconnectivitybetweenacorridorandnocorridor,andhenceintermediateinprovidingformovementofinteriorspeciesbetweenpatches.

C5.DistancebetweensteppingstonesForhighlyvisually-orientedspecies,theeffectivedistanceformovementbetweensteppingstonesisdeterminedbytheabilitytoseeeachsuccessivesteppingstone.

C6.Lossofasteppingstone

Lossofonesmallpatch,whichfunctionsasasteppingstone

formovementbetweenotherpatches,normallyinhibits(抑制,约束)movementandtherebyincreasespatchisolation.

C7.Clusterofsteppingstones

Theoptimalspatialarrangement

ofaclusterofsteppingstonesbetweenlargepatchesprovidesalternateorredundantroutes,whilemaintaininganoveralllinearly-orientedarraybetweenthelargepatches.

C8.Roadsandother“trough”corridorsRoad,railroad,powerline,andtrailcorridorstendtobecompletelyconnected,relativelystraight,andsubjecttoregularhumandisturbance.Therefore,theycommonlyserveasbarriersthatsubdividepopulationsofspeciesintometapopulations;conduitsmainlyfordisturbance-tolerantspecies,sourcesoferosion,se