Editor'snote:Asprotectionoftheplanet'sflora,faunaandresourcesbecomesincreasinglyimportant,ChinaDailyispublishingaseriesofstoriestoillustratethecountry'scommitmenttosafeguardingthenaturalworld.

Inthemist-shroudedvalleysoftheGaoligongMountainsinYunnanprovince,auniquedawnchorusechoeseachmorning—thesongoftheSkywalkerhoolockgibbon,theonlyapespeciestobenamedbyChinesescientists.Withfewerthan200individualsremaininginthewildinChina,thesurvivaloftheseendangeredprimatesnowrestswithadedicatedteamofforestguardiansandaconservationstrategythathasevolvedsignificantlyoverthepasttwodecades.

Onarecentwintermorning,wellbeforesunrise,YangYoushanbeganhisascentintotheGaoligongshanNationalNatureReserve.The50-year-oldforestrangerwassearchingforanelderlypairofSkywalkerhoolockgibbonshehastrackedfor17years—abondsodeephehaslearnedtoreadtheforestthroughtheireyes.

"Imainlyrelyontheirfood,"Yangsaid,pausingonasteeptraillinedwithnumberedtrees."Dependingontheseason—spring,summer,autumn,winter—weknowwhatfruitstheyeat,whattenderleavestheyprefer."Thisknowledge,honedthroughyearsofpatientobservation,allowshimtopredicttheirmovementsacrossalandscapemarkedbymorethan1,800catalogedfoodtrees.

Thegibbonsheguardsareshowingtheirage."Theirmovementshavebecomeslow,theirfurhasturnedblack,"Yangnoted.Thefemale,onceeasilyidentifiedbyherbrownishcoat,hasdarkenedovertime.DNAanalysisoftheirfecesandurineconfirmsthepairislongpastbreedingage.AninfantYangfirstspottedin2008hassincevanished,likelytakenbyaraptor.

"IfIdidn'thavefeelingsforthem,Idefinitelycouldn'thavedonethisfor17years,"saidthepart-timeranger,whoalsotendsasmallcoffeeplotinanearbyvillage.

Fromrumortoscience

Lastyearmarkedthe20thanniversaryofthefirstphotographofwhatwouldeventuallyberecognizedastheSkywalkerhoolockgibbon—acreaturelongmistakenforitscousinsacrossMyanmar,IndiaandBangladesh.

Thejourneyfrommisclassificationtodiscoverybeganin2007,whenresearchersledbyFanPengfeiofSunYat-senUniversitystartedquestioningtheidentityofChina'sgibbons.Photographsrevealedsubtlebutconsistentdifferences:maleslackedthewhitebeardsandeye-patchmarkingsofknownspecies,whilefemalesshowedlessprominentwhitefacialrings.

Forthenextdecade,aninternationalteampiecedtogetherevidence—examining122specimensinmuseumsacrossChina,theUnitedStatesandEurope,analyzingteethmorphology,andsequencingDNA.TheyfoundChina'sgibbonpopulationhaddivergedfromtheeasternhoolockgibbonaroundhalfamillionyearsago,atimeframecomparabletootherrecognizedprimatespecies.

OnJan11,2017,theteamformallydescribedHoolocktianxingintheAmericanJournalofPrimatology.Thenamecombined"tianxing",anancientChinesetermmeaning"heavenlymovement",withanodtoStarWars—reflectingFan'sadmirationforthefranchise'sLukeSkywalker.

WhenLiJiahuaarrivedastheinauguralchiefofthereserve'sNankangManagementStationinlate1997—whereYangnowworks—thegibbonswerebarelymorethanarumor:occasionalcallsinthemist,fleetingglimpsesbeforetheyvanished.Today,asdeputyheadofthereserve'sLongyangbureau,heoverseesatransformationfromcasualobservationtoprecisionscience.

ThebreakthroughcameonMay16,2005,whenLi'scousinandsuccessor,LiJiahong,capturedthefirstclearphotographusinganoldfilmcamera.Thatsingleimageopenedthedoorforresearchersfrommultipleuniversitiestostudythemysteriousapes.

Evolvingconservation

Overthepasttwodecades,monitoringmethodshaveadvancedindistinctwaves,expertssaid.

Around2008and2009,teamsbeganusingvocalizationtriangulation.Byfanningoutacrosstheforestandtimingthegibbons'morningcallsfrommultiplepositions,theycouldmapfamilygroupswithincreasingaccuracy.

Theearly2010sbroughtthe"three-designated"system:designatedpeoplemonitoringdesignatedapesindesignatedgroups,yearafteryear."Whenyoufirststartmonitoringthem,theyareveryafraidofpeople,"saidDingJiatuan,currentchiefoftheNankangManagementStationandYang'ssupervisor."Youhavetohabituatethem,getthemusedtoyou.Youcan'tkeepchangingthemonitors."

Thelatestinnovation,introducedjusttwoorthreeyearsago,isacousticmonitoring.Smallrecordingdevicescaptureindividualvocalfingerprints."Eachgibbonhasauniquevoice,"LiJiahuaexplained.Thisallowsresearcherstoidentifysolitaryindividualswhorarelyrevealthemselves.

Therecordingsmayeventuallyserveanewpurpose:matchmaking.Adocumentaryproject,ASongForLove:AnApewithAnApp,usedreal-timeaudiotoconnectacaptivemaleataBeijingzoowithasolitaryfemaleintheGaoligongMountains."Theyrespondedstronglytoeachother,"Lisaid—plantingtheideathatrecordingscouldonedayhelpintroduceisolatedindividualsacrossthefragmentedforest.

Thealtitudechallenge

Despiteadvances,thereserve'sgibbonpopulationhasremainedfrustratinglystable—around50individualsacross19groups,including14familiesand5solitaryadults.

Meanwhile,populationsinnearbyYingjiangcountyhavegrowntomorethan100.

Thedifferenceliesinelevation,LiJiahongexplained.Gibbonsnaturallypreferaltitudesaround1,500meters,wheretheclimateiswarmerandfoodisabundant.Butcenturiesofhumanactivity—clearingforestsforfarming,plantingsugarcaneandcoffee—havepushedGaoligong'sgibbonssteadilyupward.Today,theysurviveatelevationsof2,000metersorhigherincold,marginalhabitats.

"InYingjiang,theelevationisaround1,600to1,700meters,whichismuchmoresuitable,"Lisaid."That'swhytheirpopulationhasexpandedfaster."

Thesolution,hebelieves,ishelpinggibbonsreturntolowerelevationsbyrestoringdegradedforestsoncollectivelyownedlandbelowthereserve—creatingcorridorsandplantingfoodtreeslikelong-stamenmagnoliathatprovideyear-roundsustenance.

Sometimesthebarriersaresmallerthanamountain.Aroad,alandslideclearing,agapinthecanopy—anyofthesecanstopagibbonthatrarelydescendstoground.IncollaborationwithresearchersatSunYat-senUniversity,thereservehasbeguninstallingsimpleropebridgesatkeylocationstoconnectfragmentedforestsections.

Theprotectionstrategyextendsbeyondthereserve'scorezone.In1996,recognizingthatthegibbons'habitatwasbecomingfragmented,authoritiesestablisheda4,800-hectarebiologicalcorridorconnectingtheGaoligongshanNationalNatureReservewiththeXiaoheishanProvincialNatureReserve."Beforethis,thestate-ownedforestinbetweenwasnotwellprotected,andwildlifecouldn'tmovebetweenthetworeserves,"Dingexplained,standingattheedgeofthenow-lushcorridor.Today,thisgreenbridgeteemswithlife—infraredcamerasfrequentlycaptureredpanda,Chinesegoral,andtheincreasinglynumerousredspurfowl,proofthatprotectingtheflagshipgibbonsheltersanentireecosystem.

Alegacyoflistening

Forallthetechnologicaladvances,conservationremainsfundamentallyhuman.LiJiahuahasspentyearstraininganewgenerationofrangersandresearchers,buildingexpertiseinbotany,ornithology,andinsectecology.Hehasbecomethereserve'sunofficialstoryteller,givinghundredsoftalkstovisitingscientists,officials,andlocalcommunities.

Theoutreachmatters.Decadesago,huntersregularlyenteredthemountainswithrifles;today,suchactivityhasnearlydisappeared.Someformerhuntershavejoinedtherangerforce,transformingfrompoacherstoprotectors.

Asdusksettles,YangYoushanpointstoatalltreemarkedwithawhite,corner-notchedsign—adesignatedsleepingtree,the97thcatalogedinhisarea.Heknowstheelderlycouplewilllikelyspendthenightinoneofthesegiantswithintheirterritory.Forhim,thethousandsofmarkedtreesarenotdatapoints;theyarelandmarksinasharedlife.