John L. Harper

Abstract

This is an overview of the academic and intellectual contribution of John L. Harper to the study of, and development of, plant ecology as a science. The article includes a complete list of his publications.

Full text

5/14/2015 JohnL.HarperEcologyOxfordBibliographies
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JohnL.Harper
RoyTurkington
LASTMODIFIED:29APRIL2015
DOI:10.1093/OBO/97801998300600135
Introduction
ProfessorJohnLanderHarperCBE,FRS(b.May27,1925–d.March22,2009)revolutionizedplantecologyandhadperhapsa
greaterimpactonitsdevelopmentasamodernsciencethananyotherecologistinthe20thcentury.RaisedonafarminRugby,
England,HarperdidhisundergraduateandgraduatedegreesinOxford.HethenspentnineyearsasalecturerattheDepartment
ofAgriculture,and,in1960,hewasappointedheadofagriculturalbotanyattheUniversityCollegeofNorthWales,Bangor.He
servedaspresidentoftheBritishEcologicalSocietyin1966–1967andoftheEuropeanSocietyforEvolutionaryBiologyfrom
1993to1995;hewaselectedaFellowoftheRoyalSocietyin1978.Hetaughtusanentirelynewdisciplineandanentirelynew
waytostudyplantsbychangingthewaywethinkaboutvegetation;insteadofbeingrelativelystatic,vegetationwasviewedasa
dynamicsystemofplantpopulations,inastateofcontinuousflux,basedonbirthanddeathsofindividuals.Almostsingle
handedlyhepioneeredtheestablishmentofthefieldofplantpopulationecology.Bybringingpopulationbiologyandexperimental
approachestotheforefrontofplantecology,helinkeddemographyandselectionand,therefore,ecologyandevolution.Harper’s
ideasarenowsocentraltoplantecologythattheyhavebecomebasictoourwayofthinking.Hebegantoaskquestionsabout
plantpopulationsthatzoologistshadbeenaskingaboutanimalpopulationssinceatleastthe1930s.Althoughfacedwiththedual
difficultiesofplantplasticityandofhowtodefine“anindividualplant,”Harpernotonlyfoundwaysofansweringthesequestions,
butalsohepresentedtheanswersinawaythatconvincedusthatplantswereworthyofstudy;furthermore,plantpopulations
wereofteneasiertostudythananimalpopulationsbecausethey“standstillandwaittobecounted”(Harper1977,p.515,cited
underBooks:PopulationBiologyofPlants).TherepertoireofHarperianecologyincludedseedproduction,seedbanks,seed
dispersal,seeddormancy,seedsoilinteractions,seedlingrecruitment,effectsofneighbors,interference,populationregulation,
plantanimalinteractions,dynamicsofplantpopulations,demography,populationevolution,resourceallocation,andplantlife
histories.Hisupbringingonafarmandagriculturalbackgroundareclearlyreflectedinthesubjectsusedinmuchofhisresearch—
cropplants,grasses,andweeds—andthepastureatHenfaes,NorthWales,servedasthestudysiteforatleasttengraduate
studentsandoverseasvisitors.In1977HarperpublishedhismonumentalPopulationBiologyofPlants.
Biography
AdetailedprofileofHarper’slifeuntil1985isprovidedinSagar1985andinobituariesinFranco,etal.2009andTurkington2009.
JohnLanderHarperwasbornonMay27,1925,intoafarmingfamily.HewaseducatedatLawrenceSheriffSchool,Rugby,
where,undertheenthusiasticleadershipofWilfredKings,hedevelopedadeepenthusiasmfornaturalhistory.Attheageof
thirteen,Harperobservedandcountedbuttercupsalongatransectacrossanundulatingpastureonhisfather’sfarm(Harper
1989).Henotedthatdifferentspeciesofbuttercupsgrewindifferentpartsofthepasture(personalcommunication).In1943he
enteredMagdalenCollege,Oxford,andgraduatedwithafirstclasshonorsinbotanyin1946,followedbyamaster’sdegreeanda
doctorateinphilosophyin1950,completedunderthesupervisionofDr.J.L.Harley.Harperwasthenappointedasa
demonstratoratOxfordUniversityin1951andpersonallyacknowledgesthatG.E.Blackmanwas“exceptionallysupportivein
helpingmetoacquiremyowngroupofD.Phil.students;G.R.SagarandI.H.McNaughtoncametomefromtheOxfordBotany

5/14/2015 JohnL.HarperEcologyOxfordBibliographies
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DepartmentandJohnClatworthycamefromRhodesiaasaRhodesScholar”(J.L.Harper,unpublishedmemoirs;providedby
Claire,hisdaughter).From1953to1959hewaslecturerintheDepartmentofAgricultureand,afterasabbatical(1959–1960)asa
RockefellerFoundationfellowattheUniversityofCalifornia,Davis,hewasappointedheadofagriculturalbotanyattheUniversity
CollegeofNorthWales(UCNW),Bangor.In1967theDepartmentsofBotanyandAgriculturalBotanymergedandHarperbecame
headofthenewSchoolofPlantBiology.Heretainedthatpositionuntil1982.AtthistimehewasalsopresidentoftheBritish
EcologicalSociety(BES)(1966–1967).TheSchoolofPlantBiologyatBangorbecamethemeccaforplantpopulationbiologists.It
becameidentifiedwithalmosteverythingnewemerginginthefieldofplantpopulationecology,attractinggraduatestudentsand
visitorsfromallovertheworld.In1982HarperbecameemeritusprofessoratUCNW,buthecontinuedasheadof“TheUnit”—the
UnitofPopulationBiology,SchoolofPlantBiology,UCNW.JohnHarperservedaspresidentoftheEuropeanSocietyfor
EvolutionaryBiologyfrom1993to1995,andheservedasavisitingprofessorattheUniversityofExeterin1998.
Franco,Miguel,JoséSarukhán,andRodolfoDirzo.2009.ADarwinianplantecologist,JohnLanderHarperCBEFRS,
1925–2009.InMemoriesofJohnL.Harper:Aremembrancebyhisfriends,students,andcolleagues.2ded.Editedby
GlennR.Matlack,98–100.Bangor,UK:JPB.
ThisonlineresourcewrittenbythreeofHarper’sgraduatestudentsprovidesanoverviewofHarper’sacademiccareerand
influence,andhowthisinfluencehasspreadintosuccessivegenerationsofMexicanstudents,contributingtothestudyand
conservationofMexico’sbiodiversity.
Harper,JohnL.1989.Plantdemography:AcitationclassiccommentaryonPopulationBiologyofPlantsbyJohnL.
Harper.CurrentContents/Agriculture,BiologyandEnvironmentalSciences5:14.
Inthisonepagearticle,HarperoutlineswhythetimewasripeforhiswritingofPlantPopulationBiology;henotesthat“plant
ecologywasinthedoldrums;itwasrarelyexperimentalandcouldnotlinkeasilywithevolutionarytheory”(p.14).Atthetimeof
writingthisarticle,thebookhadbeencitedinmorethan1,660publications.
Sagar,GeoffR.1985.ProfileofJohnL.Harper.InStudiesofplantdemography:AfestschriftforJohnL.Harper.Edited
byJamesWhite,xix–xxv.London:AcademicPress.
ThisprofilewaswrittenbyoneofHarper’searlygraduatestudentsandlongtimefriendandcolleague.Thusitprovidesextra
detailsofHarper’searlyenthusiasmfornaturalhistory,hisearlyacademicachievements,andthehistoryofthedevelopmentof
theSchoolofPlantBiologyinNorthWales.
Turkington,Roy.2009.Obituary:ProfessorJohnL.Harper,FRSCBE,1925–2009.JournalofEcology97:835–837.
ThistributetoJohnHarperwaswrittenbyaformergraduatestudentandprovidesadescriptionofHarper’spersonality,the
developmentofhisresearchapproach,hisfamilylife,responsesofthosearoundhiminBangor,andanumberofdirect
“Harperian”quotations.ReprintedinBulletinoftheEcologicalSocietyofAmerica91(2010):9–13.
AwardsandService
JohnHarperwasmadeafellowoftheRoyalSocietyin1978(Anonymous1978),anhonoraryassociateoftheSwedishSocietyfor
Phytogeographyin1981andaforeignassociateoftheUSNationalAcademyofSciencesin1981.In1984hewasrecognizedby
theEcologicalSocietyofAmericaas“eminentecologist”(Werner1985).Alsoin1984,theUniversityofSussexawardedhiman
honorarydoctorate(D.Sc.),andin1989hewasmadeanofficeroftheOrderoftheBritishEmpire(CBE).TheRoyalSociety
awardedJohnHarpertheDarwinmedal(Anonymous1990).TheNationalUniversityofMexicoawardedhimanhonorary

5/14/2015 JohnL.HarperEcologyOxfordBibliographies
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doctorate1996.HewasgiventheMillenniumBotanyAwardbytheInternationalBotanicalCongressin1999andtheMarshAward
bytheBritishEcologicalSocietyin2000(Anonymous2000).From1971to1998JohnHarperservedinvariousadvisoryrolesfor
bodies,includingtheNaturalEnvironmentResearchCouncil,theRoyalSociety,theAgriculturalandFoodResearchCouncil,the
ComitėduDirection,C.E.P.E.(C.N.R.S.),theJointNatureConservationCommittee,andasaTrusteeoftheBritishMuseumof
NaturalHistory.Healsoheldvariouseditorialroles,includingeditorinchiefofAgroecosystems(1974–1981),coeditorof
Oecologia(1982–1994),assistanteditorofPhilosophicalTransactionsoftheRoyalSociety,(1990–1992),assistanteditorof
ProceedingsoftheRoyalSociety(1980–1982),andeditorofProceedingsoftheRoyalSocietyofLondon,SeriesB(1992–1998).
Anonymous.1978.Harper,JohnLander(EC/1978/12).RoyalSocietyofLondon.
PartofthecitationstatesthatJohnHarperwas“Distinguishedforhisresearchesinplantecology,especiallyontheautecologyof
selectedspeciesandontheestablishment,interactionandcompetitionofcloselyrelatedspecies.Hiw(sic)workischaracterized
byacuteobservations,ingeniousbutsimplefieldandlaboratoryexperimentsandrigorousstatisticalappraisal.”
Anonymous.1990.TheDarwinmedal:AwardedtoJ.L.HarperbytheRoyalSocietyofLondon.RoyalSocietyNews5:4.
Partofthecitationreads:“Byhisbreadth,originalityandimaginativeexperimentationhehasbecomeaworldleaderinthefieldof
plantecology”(p.4).
Anonymous.2000.MarshAwardforecology:AwardedtoJ.L.HarperbytheBritishEcologicalSociety.Bulletinofthe
BritishEcologicalSociety31:15.
Thisawardwasgivenfor“pioneeringawholenewfieldofscientificendeavor:thepopulationbiologyofplants[and]the
developmentofthescienceofplantecology”(p.15).
Werner,Patricia.1985.Eminentecologistcitation:AwardedtoJ.L.HarperbytheEcologicalSocietyofAmerica.Bulletin
oftheEcologicalSocietyofAmerica66:20–21.
PartofthecitationstatesthatJohnHarper“revolutionizedplantecology...noonehashadmoreinfluenceonplantpopulation
ecologyduringtheperiodofitscomingofage”(p.20).Availableonlineforpurchase.
AcademicDevelopment
ManycircumstancesandindividualsinfluencedHarper’sacademicdevelopment.Harperpublicallyrecognizedtheinfluenceof
WilfredKings,hishighschoolbiologyteacher,inthededicationofPopulationBiologyofPlants:“toW.K.,TeacherandFriend.”At
amuchbroaderlevelhewasprofoundlyinfluencedbyCharlesDarwinandnofewerthanfifteendirectquotationsfromTheOrigin
ofSpeciesarefoundinHarper’spresidentialaddresstotheBritishEcologicalSociety—ADarwinianApproachtoPlantEcology
(Harper1967;citedunderBackgroundDevelopment:UniversityCollegeofNorthWales(UCNW),BangorandEvolutionary
Ecology).DuringhistenureatOxford,HarperwasprobablymostinfluencedbyG.E.Blackmanandhedevelopedhisdistinctive
styleofplantecologicalresearchthatincorporatednaturalselection,experimentsandtheory.Hisdevelopmentwasalsoshaped
byArthurG.Tansley’smanner,albeitshortterm,ofdoingexperiments(Tansley1913),andAlexS.Watt’sextendedfield
observationsanddetailedanalysisofproximalecologicaleventsinvolvingthemonitoringofindividuals(Watt1947).Harperwas
alsoinfluencedbyJohnMaynardSmith’sanalysisofevolutionarytheoryandoftheroleofsexualreproductionasacrucialfactor
inevolutionandinthesurvivalofspecies.Harperacknowledgesthathehadgreatteachers,CharlesEltonandGeorgeVarley
(Varley1957),“animalecologistwhogavemegreatencouragementwhentheworkwasviewedbygreatsuspicionbyplant

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ecologists”(Harper1989,p.14,citedunderBiography).AndhehailsLedyardStebbinsandBobAllard,who“bothforcedmeto
thinkasanevolutionist”(p.14).OftenoverlookedistheinfluenceofHarper’sdepartmentalcolleagueinBangor,ProfessorPeter
GreigSmith.Duringthe1960secologistsactivelydebatedtheroleofreductionismandholismastoolstounderstandecological
phenomena.Thedebatewascarriedonworldwide,andittookplaceinamesocosminBangor.JohnHarperwasastrong
proponentofanexperimentalandreductionistapproachtoecologicalresearch,andPeterGreigSmithwasaquantitative
ecologistseekinglargescalepatternsinvegetation.AsdescribedinHill2003andMatlack2009,HarperandGreigSmith
engagedinfrequent,goodhumoreddebatesfollowingdepartmentalseminars,which“wereconductedamidlegendarycloudsof
pipesmoke”(Ezcurra2014).Thesestimulating,rigorous,andgoodnatureddiscussionsnotonlylikelysharpenedtheintellectual
abilitiesofHarperandGreigSmith,buttheyalsohadadeepinfluenceonagenerationofBangorianstudents.Seealsothe
OxfordBibliographiesarticlebyExequielEzcurra“PeterGreigSmith.”
Ezcurra,Exequiel.2014.“PeterGreigSmith.”InOxfordBibliographiesinEcology.
AbibliographicaccountofPeterGreigSmithdescribinghisearlyworkonsanddunesandtropicalecology,hismovetothe
UniversityCollegeofNorthWales(Bangor).Thereisgreatcoverageofhiscontributiontotheintellectualdevelopmentof
multivariateanalysis,classificationandordination,especiallythroughtheworkofhisacademicoffspring.
Hill,MarkO.2003.PeterGreigSmith,1922–2003.BulletinoftheBritishEcologicalSociety34.4:10–11.
MarkHill,aformerstudentofPeterGreigSmithatBangor,wroteadetailedobituaryforGreigSmith.
Matlack,GlennR.,ed.2009.MemoriesofJohnL.Harper:Aremembrancebyhisfriends,students,andcolleagues.2ded.
Bangor,UK:SPB.
AcompilationofalmostfortyshortcontributionsfromformerstudentsandcollaboratorsofJohnHarper.Theserecollections
describeallfacetsoflifeandexperiencesinHarper’sBangorlab,includingacademic,personal,andhumorous.Alsocitedunder
Biography.
Tansley,ArthurG.1913.AreviewofBrockmannJerosch,H.andRubel,E.:Auniversalclassificationofplant
communities:DieEinteilungderPflanzengesellschaftennachOkologischPhysiognomischenGesichtspunkten.Journal
ofEcology1:27–42.
InthisveryfirstvolumeoftheJournalofEcology,TansleycriticallyreviewsBrockmannJeroschandRubel’sbookandarguesthat
atrulyinductivesciencethatwillhelpusunderstandthosefeaturesthatdeterminevegetationcanbeestablishedonlyby
comparison,byobservation,andbyexperiment.
Varley,GeorgeC.1957.Ecologyasanexperimentalscience.JournalofAnimalEcology26:251–261.
ThispresidentialaddresstotheBritishEcologicalSocietyarguesthecaseforexperimentalecology.
Watt,AlexS.1947.Patternandprocessintheplantcommunity.JournalofEcology35:1–22.
Wattdescribestheplantcommunityas“aworkingmechanism,whichmaintainsandregeneratesitself.”Histhesisisthatplant
communitiesareamosaicofpatchesatdifferentstagesofregeneration,andthisideapavedthewayforthestudyofpatch
dynamics.

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BackgroundDevelopment
JohnHarperspenthisentireacademiccareeratOxfordandinNorthWales.AtOxfordhedevelopedhisdistinctivestyleof
researchdescribedearlier,onethatincorporatednaturalselection,experiments,andtheory.ItwasatOxfordthatheandhis
studentsbegantostudyfinescaleinteractionsamongseeds,seedlings,andtheirenvironment.TheOxfordyearspavedtheway
foranentirelynewapproachtothestudyofplantecologythatwastoflowfromBangor.
Oxford,DepartmentofAgriculture
WhileatOxfordduringthe1950sHarper,LandraginandLudwigbeganaseriesofstudiesontheinfluenceoftheenvironmenton
seedandseedlingmortality(Harper,etal.1955).Duringthissameperiod,Harperalsogaveincreasingattentiontothestudyof
weeds,andfrom1953to1960hepublishedtenpapersonweeds,particularlyRanunculusspp.(HarperandSagar1953)and
Plantagospp.,andtheseincludedsomeclassicecologicalpapers(Harper1957,Harper1960).Theseearlystudiesproducedthe
ninepaper“thecomparativebiology”seriesthatbeganaftermanyrigorousandvigorousdiscussionsamongIanMcNaughton,
JohnClatworthy,andGeoffSagartogetherwithJohnHarper.Thesefourindividualswereperplexedbythediversityofnatural
vegetationandwhysomanyspeciescouldcoexist,oftencloselyrelatedspecies,especiallyinlightofbothGause’scompetitive
exclusionprincipleandbecauseDarwinarguedthattheseverestcompetitionshouldcomefromthemostsimilarspecies
(McNaughtonandHarper1960;Harper,etal.1961;HarperandMcNaughton1962).BeforeHarperleftOxfordheorganizedthe
firstsymposiumoftheBritishEcologicalSocietytitled“TheBiologyofWeeds”;hewaseditoroftheresultingbook(Harper1960;
citedunderBooks:TheBiologyofWeeds)aswellastheauthoroftwochapters(e.g.,Harper1960).Laterhepresentedthe
keynoteaddresson“ApproachestotheStudyofPlantCompetition”(Harper1961)atasymposiumoftheSocietyforExperimental
Biology.
Harper,JohnL.1957.Theecologicalsignificanceofdormancyanditsimportanceinweedcontrol.Proceedingsofthe
IvthInternationalCongressofCropProtection,Hamburg1990.EditedbyJohannesKrause,415–420.Brunswick,
Germany:InternationalCongressofCropProtection.
Thispapersetthestagefornumerouspapersonweedseeddormancyandgerminationandisstillcited.
Harper,JohnL.1960.Factorscontrollingplantnumbers.InThebiologyofweeds.ByJohnL.Harper,119–132.British
EcologicalSocietySymposium1.Oxford:Blackwell.
Arguablyoneoftheearliestexperimentalplantecologypaperstogiveseriousattentiontodensitydependentregulationinplant
populations,referringspecificallytotheweedyspeciesPapaverspp.andAgrostemmagithago.
Harper,JohnL.1961.Approachestothestudyofplantcompetition.InMechanismsinbiologicalcompetition.Editedby
theSocietyforExperimentalBiology,1–39.SymposiaoftheSocietyforExperimentalBiology15.NewYork:Academic
Press.
Thispapercomparesthemanyandvariedmethodsusedbyphysiologists,agronomists,ecologists,andgeneticiststostudy
competition.
Harper,JohnL.,JohnN.Clatworthy,IanH.McNaughton,andGeoffR.Sagar.1961.Theevolutionandecologyofclosely
relatedspecieslivinginsamearea.Evolution15:209–227.
Thissixteenpageessayclassic“wasfinallypublishedin1961butnotbeforetwoprestigiousandsubsequentlyreformedBritish

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journalshaddeclinedtodoso,presumablybecausethetreatmentwassofarremovedfromthecurrentmainstreamofecological
researchintheplantsciences”(Sagar1985,pp.xxi–xxii;citedunderBiography).
Harper,JohnL.,PhyllisA.Landragin,andJerzyW.Ludwig.1955.Theinfluenceofenvironmentonseedandseedling
mortality,I:Theinfluenceoftimeofplantingonthegerminationofmaize.NewPhytologist54:107–118.
Thisisthefirstinaseriesofeightpapersshowinghowmicroscaleheterogeneityofthesoilsurfacecanactasafilterorsieve
allowingsomeseedstogerminatebutpreventingothers.MaizewasusedbecauseG.E.Blackman(UnitofExperimental
Agronomy,Oxford)wasconsideringitspossibleuseasacropinBritain.
Harper,JohnL.,andIanH.McNaughton.1962.Thecomparativebiologyofcloselyrelatedspecieslivinginthesame
area,VII:InterferencebetweenindividualsinpureandmixedpopulationsofPapaverspecies.NewPhytologist61:175–
188.
ThisisthefirstofmanystudiesinwhichHarper’slabmadeuseofthedeWitreplacementseriesapproachtostudyingplant
“competition”(interference).Unaccountably,deWitisnotcitedinthetextbuthisnameisincludedinthelistofreferences.Harper
championedthismethodasapowerfulwaytoexperimentallydissectthecomplexityofplantinterference.
Harper,JohnL.,andGeoffR.Sagar.1953.Someaspectsoftheecologyofbuttercupsinpermanentgrasslands.In
ProceedingsoftheBritishWeedControlConference.EditedbyBritishCropProtectionCouncil,256–263.Brighton,UK:
BritishCropProtectionCouncil.
ThispapermarkedthebeginningofHarperianecologyandpavedthewayforagenerationofstudiesonplantpopulation
dynamics.ThispaperharborstheoriginsoftheRanunculuswork,thePapaverwork,andtheserieson“closelyrelatedspecies
livinginthesamearea.”
McNaughton,IanH.,andJohnL.Harper.1960.Thecomparativebiologyofcloselyrelatedspecieslivinginthesame
area,I:ExternalbreedingbarriersbetweenPapaverspecies.NewPhytologist58:15–26.
ThefirstinaseriesofninearticlesthatdealwithhowcloselyrelatedspeciescouldcoexistgivenGause’scompetitiveexclusion
principleandDarwin’sargumentthattheseverestcompetitionshouldcomefromthemostsimilarspecies.Thetheoreticaland
philosophicalbackgroundtothisseriesisHarper,etal.1961.
UniversityCollegeofNorthWales(UCNW),Bangor
TheOxfordyearswereproductiveandtheyprovidedanintellectualenvironmentthatpromotedthedevelopmentofafoundation
forawholeneweraofplantecologicalthoughtandresearchthatwastoflowfromBangor,muchofwhichisencapsulatedin
Harper1964a,Harper1964b,andHarper1965aswellasHarper1967(alsocitedunderEvolutionaryEcology),Harper1968(also
citedunderRegulation),andHarper1969.ItwasfromBangorthatmanyseminalandinfluentialpaperswerepublishedandto
whichmanygraduatestudents,doctoralgraduates,andothervisitors,mostoftenfromoverseas,wereattracted.Harperandhis
labcontinuedwiththeDarwinianthemeandprobedplantpopulationbiologywithparticularemphasisonreproductiveallocation,
interference,populationdynamics,anddemography.
Harper,JohnL.1964a.Theindividualinthepopulation.JournalofAnimalEcology33:149–158.

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Thispaperbringstogethersomeexamplesofplantinteractionsthatresultinchangesinthebehaviorofindividualsasthey
becomeinfluencedbytheproximityoftheirneighbors.Availableonlineforpurchase.
Harper,JohnL.1964b.Thenatureandconsequenceofinterferenceamongstplants.InGeneticstoday:Proceedingsof
theXIthInternationalCongressofGenetics,TheHague,theNetherlands,September1963.Vol.2.EditedbyS.J.Geerts,
465–482.Oxford:Pergamon.
Thispaperstressestheneedforseriousattentiontobepaidtothewaysinwhichplantsmayinterferewitheachotherandthe
consequencesofthisinterference.
Harper,JohnL.1965.Establishment,aggression,andcohabitationinweedyspecies.InThegeneticsofcolonizing
species.EditedbyHerbertG.BakerandG.LedyardStebbins,243–263.NewYork:AcademicPress.
ThispapercaughttheattentionofthefamousAmericanbiologistsE.O.Wilson,G.L.Stebbins,ErnstMayr,andHerbertBaker.
ThispresentationarguablyopenedHarper’sgatewaytotheecologicalaudienceintheUnitedStates.Thepaperconcludesthat
germinationandseedlingestablishmentarethemostimportantfactorsforsuccessfulspreadandresistancetonativeflora.
Harper,JohnL.1967.ADarwinianapproachtoplantecology:Presidentialaddress,BritishEcologicalSociety.Journalof
Ecology55:247–270.
Thisenormouslyinfluentialpaperbecameaninstantclassicintheecologicalliteratureandinspiredanentiregenerationofplant
ecologists.Thissinglepaperdescribes,orintroduces,muchofHarper’sresearchcareer.Thispaperwaslistedas“oneofthetop
100mostinfluentialpaperspublishedbytheBritishEcologicalSociety(1913–2012)”aspartoftheBEScentenarycelebrations.
AlsoavailableinJournalofAppliedEcology4(1967):267–290,andJournalofAnimalEcology36(1967):495–518.
Harper,JohnL.1968.Theregulationofnumbersandmassinplantpopulations.InPopulationbiologyandevolution.
EditedbyRichardC.Lewontin,139–158.NewYork:SyracuseUniv.Press.
Thekeywordinthistitleis“plant.”Harperargueswhyitisriskytouncriticallyapplypopulationtheoryderivedforanimals,to
plants.Healsodiscusses“theindividualasapopulation,”dormancy(whichanimalsdon’treallydo!),anddeWitmethodsof
studyingplantcompetitionandregulation.
Harper,JohnL.1969.Theroleofpredationinvegetationaldiversity.InDiversityandstabilityinecologicalsystems:
ReportofasymposiumheldMay26–28,1969.EditedbyG.M.WoodwellandH.H.Smith,48–62.BrookhavenSymposiain
Biology22.Upton,NY:BrookhavenNationalLaboratory.
Thispapercautionsthatjustbecausetheworldisgreendoesnotmeanthatherbivoresareunimportanttoplants.Threemajor
typesofexperimentaredescribedthattesttheeffectsofherbivoresonvegetation.AlsocitedunderDarwinianandWallacian
Perspectives.
ResearchFramework
ThroughouthiscareerHarperusedhissingleauthorshippapers,whichwereoftenpublishedproceedingsfrominternational
conferences,todevelopandpresenthiscorescientificframework.Manyofthesewerebasedonpurescholarshipratherthanthe

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usualconventionalreviewsanditisfromthesepapersthathisideas,arguments,andquestionswereformulated,manyofwhich
remainunanswered,andfromwhichHarper’suniqueacademicresearchphilosophycaneasilybeidentified,namelynatural
selection(evolutionaryecology),experiments,andtheory.
EvolutionaryEcology
Harper’sfoundationalthemewasthatDarwin’stheoryofevolutionbynaturalselectionisanecologicaltheoryandthatecologyis
evolutioninaction(Harper1967,alsocitedunderBackgroundDevelopment:UniversityCollegeofNorthWales(UCNW),Bangor,
Harper1983).ThisisrootedinDarwin’semphasisontherolethatindividualdifferencesplayinevolutionbynaturalselection
(Harper1964a,citedunderBackgroundDevelopment:UniversityCollegeofNorthWales(UCNW),Bangor),yetthestudyofthe
fateofindividualplantswaslargelyignored.Hepioneeredafieldofstudyinwhichthefateofindividuals,andthemechanismby
whichtheyleavedescendants,wasparamount.
Harper,JohnL.1967.ADarwinianapproachtoplantecology:Presidentialaddress,BritishEcologicalSociety.Journalof
Ecology55:247–270.
HarperdevelopshisfoundationalthemethatDarwin’stheoryofevolutionbynaturalselectionisanecologicaltheory.Thereareat
leastfifteenquotationsfromchapters3and4ofDarwin’sOriginofSpecies,numerousquestionsareposed,andthepaper
emphasizestherolethatindividualdifferencesplayinnaturalselection.AlsoavailableinJournalofAppliedEcology4(1967):
267–290,andJournalofAnimalEcology36(1967):495–518.
Harper,JohnL.1983.ADarwinianplantecology.InEvolutionfrommoleculestomen.EditedbyD.Bendall,323–345.
Cambridge,UK:CambridgeUniv.Press.
ThispaperbrieflyreviewsandcontraststhescientificapproachesofDarwinandWallace.Harpercommendstheearlymodeling
workofNägeliinthe1870sandGause,andheapplaudsthelongtermstudiesofTamm(andothers)whomadepermanentplots
andmonitoredthefateofindividuals.
DarwinianandWallacianPerspectives
Studiesdescribingpatternsofdifferentiationinplantpopulationshavebeenundertakenformorethan250years.Langlet1971
cites111referencesthatarepre1900,sixofwhicharefromthe1700s.Inmostcasestheprocessesgeneratingthepatternswere
largelyignoreduntilthe1960s.MostofthispreviousworkhadbeendominatedbywhatHarpercalls“aWallacianattitude”(Harper
1977,citedunderBooks:PopulationBiologyofPlants).Wallacethoughtofnaturalselectionasprimarilyastruggleagainstthe
physicalfactorsoftheenvironment,suchasmoisture,temperature,orsoiltype,withtheresultthatdifferenttypesoforganisms
liveindifferentenvironments.Suchstudieswereimportantandoftenclearlydemonstratedthatmicroevolutionoccurredoververy
shortdistances,ofteninthepresenceofextensivegeneflowandoverrelativelyshorttimeintervals.Incontrast,Darwin
emphasizedtheroleofbioticfactors,suchascompetitionandherbivory,andsoughttounderstandhowsomanytypesofplants
(andanimals)couldcoexistandavoidelimination.Harperhighlightedthiswhenhewrote“itisthereforeratheroddthatalthoughit
isDarwin’sinfluencethatisusuallyacknowledgedinthedevelopmentofevolutionarytheory,itisaWallacianattitudethathas
dominatedthestudyofadaptationinplants”(Harper1977,p.750).Keypaperswiththisemphasisontheimpactofbioticfactors
onplantpopulationsareHarper1969(citedunderBackgroundDevelopment:UniversityCollegeofNorthWales(UCNW),
Bangor),TurkingtonandHarper1979,Burdon1980,DirzoandHarper1982a,andDirzoandHarper1982b.
Burdon,JeremyJ.1980.IntraspecificdiversityinanaturalpopulationofTrifoliumrepens.JournalofEcology68:717–
735.

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Inthispaper,fiftyclonesofTrifoliumrepensweresampledfromthefieldatHenfaes.Theywerescreenedforanumberoftraits,
mostofwhichwereselectivelyimportant,includingsusceptibilitytosomepathogens.Theclonesdifferedfromoneanotheron
averageby3.3vegetativecharacters.Availableonlineforpurchase.
Dirzo,Rodolfo,andJohnL.Harper.1982a.Experimentalstudiesonslugplantinteractions,III:Differencesinthe
acceptabilityofindividualplantsofTrifoliumrepenstoslugsandsnails.JournalofEcology70:101–118.
FieldandlaboratorytrialsusingfourspeciesofsnailsandslugsshowedthatcyanogenesisinTrifoliumrepens(whiteclover)
markedlyreduced,butdidnotcompletelyprevent,damagetocloverleavesbythegrazingmollusks.Ahypotheticalcoevolutionary
interpretationofthemolluskcyanogenesisinteractioninwhitecloverispresented.
Dirzo,Rodolfo,andJohnL.Harper.1982b.Experimentalstudiesonslugplantinteractions,IV:Theperformanceof
cyanogenicandacyanogenicmorphsofTrifoliumrepensinthefield.JournalofEcology70:119–138.
Duringthegrowingseasoninapermanentpasture,pathogensdamagedleavesofcyanogenicandacyanogenicmorphsof
Trifoliumrepens(whiteclover),butinfectionbythesystemicrustUromycestrifoliiwasalmostexclusivelyonacyanogenicmorphs.
Mollusksconsistentlypreferredacyanogenicmorphsandweevilsappearednottobedeterredbycyanogenesis,
Harper,JohnL.1969.Theroleofpredationinvegetationaldiversity.InDiversityandstabilityinecologicalsystems:
ReportofasymposiumheldMay26–28,1969.EditedbyG.M.WoodwellandH.H.Smith,48–62.BrookhavenSymposiain
Biology22.Upton,NY:BrookhavenNationalLaboratory.
Threemajortypesofexperimentaredescribedthattesttheeffectsofherbivoresonvegetation.
Langlet,O.1971.Twohundredyearsgenecology.Taxon20:653–722.
ThispaperwrittenmostlyinEnglish,butwithnumerousnonEnglishquotations,providesadetailedhistoryofthedisciplineof
genecology.Itprovidesanexhaustivebibliographyondifferentiationin“vegetation,”includingsixpapersfrombefore1800.
Turkington,Roy,andJohnL.Harper.1979.Thegrowth,distributionandneighbourrelationshipsofTrifoliumrepensina
permanentpasture,IV:Finescalebioticdifferentiation.JournalofEcology67:245–254.
Thiswasthefirstpapertodemonstratethataplantpopulationcoulddifferentiateinresponsetotheidentityofitsneighbors,that
is,thebioticenvironment,independentoftheabioticfactorsoftheenvironment.Thepaperwaslistedas“oneofthetop100most
influentialpaperspublishedbytheBritishEcologicalSociety(1913–2012).”
IndividualsinaPopulationandthePlant’sEyeView
AnunderlyingthemeofHarper1967(citedunderBackgroundDevelopment:UniversityCollegeofNorthWales(UCNW),Bangor
andEvolutionaryEcology)andofHarper1977(citedunderBooks:PopulationBiologyofPlants)PopulationBiologyofPlantsis
thatthetheoryofevolutionbynaturalselectionisanecologicaltheory.Harperstressesthatthebiologyofaspeciesgrowingin
isolationmaynotaccountforitsecology.Asanindividualplantcomesintoproximitywithotherindividualsofthesameandof
differentspecies,typicallymarkedchangestakeplaceinthebehaviorofthatindividual(Harper1964).Harperwasconcernedthat
experimentsonpopulationsnotbeconfusedwithexperimentsonindividuals.WhileaDarwinianisinterestedinpopulationlevel
processes,itistheresponseoftheindividualswithinapopulationtothepresenceoftheirneighborsthatiscritical.Amajor

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disadvantageofdescriptivepopulationbehavioristhatitfocusesonmeanyield,ormeanplantperformance,andtherebymasks
theexistenceofplanttoplantvariation;yet,itisthisvariationbetweenindividualsthatisthedrivingforceofnaturalselection
(Harper1964).ThisindividuallevelfocusishighlightedinRossandHarper1972;MackandHarper1977;andMithen,etal.1984.
Ifwearetoseeevolutionaryprocessesinactioninplantcommunitieswemustdrawourattentionawayfromanthropomorphic
scalesofsquaremetersand,instead,focusonthescaleappropriatetotheorganismwearestudying—thisisaskingforaplant’s
eyeviewofthecommunity,asillustratedinHarper1977andTurkingtonandHarper1979.
Harper,JohnL.1964.Theindividualinthepopulation.JournalofAnimalEcology.33:149–158.
Thispaperdealswithindividuals,thedifferencesbetweenthem,andhowbetweenplantvariationissocriticalwhenplantscome
intoproximitywiththeirneighbors.Availableonlineforpurchase.
Harper,JohnL.1977.Thecontributionsofterrestrialplantstudiestothedevelopmentofthetheoryofecology.In
Changingscenesinnaturalsciences,1776–1976.EditedbyClydeE.Goulden,139–157.SpecialPublication12.
Philadelphia:AcademyofNaturalSciences.
Theideaofviewingvegetationfroma“plant’seyeview”isintroduced.
Mack,RichardN.,andJohnL.Harper.1977.Interferenceinduneannuals:Spatialpatternandneighbourhoodeffects.
JournalofEcology65:345–363.
Thispaperexploresthedynamicsofinterferenceinfivesandduneannualsinagreenhouseexperimentusingarangeofdifferent
mixtures;13,000individualplantsweremapped.
Mithen,Richard,JohnL.Harper,andJacobWeiner.1984.Growthandmortalityofindividualplantsasafunctionof
availablearea.Oecologia62:57–60.
The“barearea”aroundafocalplantisagoodpredictorofplantweight.Asplantsgrow,therelationshipchangesbetweenplant
weightand“barearea”available.Plantsinsmallpolygonsaremuchmorelikelytodiethanthoseinlargerareas.
Ross,MaxA.,andJohnL.Harper.1972.Occupationofbiologicalspaceduringseedlingestablishment.Journalof
Ecology60:77–88.
Thegrowthrateofanindividualdevelopingseedlingislargelyaccountedforbythedistancetothenearestneighborsanditsstage
ofgrowth.
Turkington,Roy,andJohnL.Harper.1979.ThegrowthdistributionandneighbourrelationshipsofTrifoliumrepensina
permanentpasture,I:Ordinationpatternandcontact.JournalofEcology67:201–218.
Ifthespeciesthemselvesaretheprimedeterminantsofeachother’sdistribution,itisofinteresttoaskhowthespecies
themselvessamplethevegetation.Aplant’seyeviewofthecommunitywasrecorded,usingamethodinwhichtheplant
themselvesarethesamplingpoints.
ExperimentalEcology

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PriortoHarper’sstudies,plantecologyhadbeendominatedbythedescriptionofvegetationandtheanalysisofthebiologyof
individualspecies.TheDarwinianapproachfocusingonindividualsandthehazardstheyexperiencehadabriefappearanceon
theecologicalsceneinthe1920s.Threeleadingecologists—ClementsintheUnitedStates,SukatschevinRussia,andTansleyin
England—allcarriedoutsimplecompetitionexperimentsusingdeliberatelysownplantpopulations(Harper1983),andthenthey
promptlydroppedthispursuitandreturnedtodescriptivevegetationstudies.Harperwrites:“itisnaturalthatthefirststagesinthe
growthofanyscience(physicalorbiological)shouldconsistofthedescriptionandorderingofthematerialforstudy.Thenext
stageistosearchforcorrelationsbetweenandcausationofwhathasbeendescribed”(Harper1982,p.12).Harper’s
experimentalapproachwasevidentfromhistimeasafirstyeargraduatestudenttutortoundergraduatesintheDepartmentof
Agriculture,Oxford,in1947atagetwentytwoyears.Harperwrites:“Wewereterriblyshortofstandardlaboratoryequipmentthat
wouldhavebeenusedinconventionalpracticalclasses.Weevenhadnoclassmicroscopes.Mostofmylaboratoryexperiments
wereabsurdlysimpleandinvolvednomoreequipmentthanapacketofseedsandsomepotsofsoil.Astudentcoulddesign
experimentstoanswersimplequestionssuchas:Doesthedepthatwhichseedsaresownaffectthetimeatwhichseedlings
emerge?Doesitdependonthespecies?Doescompactingthesoilhaveaneffect?Whenseedlingsof,forexample,radish
emergefromthesoildotheygrowmoreslowlyifoneoftheirtwoseedlingleavesisremoved?Ifhalfofeachofthetwoseedling
leavesisremovedistheeffectthesameasremovingonewholeleaffromthepair?”Hecontinues“Agoodclassexperimentought
toteachtheelementsofhowscienceworksandshouldbewrittenupinawaythatexamineswhattheresultsmeanandwhatthey
don’t.Experimentsofthissortprovidequantitativedataforlogicalexperimentaldesign,primitivestatisticalanalysisandalsofor
argumentaboutrepeatability.Iftwostudentsdothesameexperimentatthesametimewilltheygetexactlythesameresult?Ifone
studentrepeatsthesameexperimentatdifferenttimeswillitgiveexactlythesameresults?(Itusuallydoesn’t).Howwaryshould
onebeindrawingconclusions.Ihadcertainlyneverbeentaughtscienceinthiswayeitheratuniversityoratschool”(J.L.Harper,
unpublishedmemoirs;providedbyClaire,hisdaughter).Monitoringofpopulationsandofindividualsoftenproducesvaluable
informationbutitisecologicallynotveryusefulunlessthemonitoringiscoupledwithexperimentstounderstandthemechanisms
underlyingobservedchanges.Yet,despitetheemphasisonexperimentalecology,Harperalsorecognizedthevalueand
necessityofdetaileddescriptiveobservationsasapreludetoexperimentaltesting.ThefieldatHenfaeswasoftenusedinsucha
way,asdetailed,forexample,inCahnandHarper1976,TurkingtonandHarper1979,andDirzoandHarper1982.
Cahn,MartinG.,andJohnL.Harper.1976.ThebiologyofleafmarkpolymorphisminTrifoliumrepensL.,I:Distribution
ofphenotypesatalocalscale.Heredity37:309–325.
DetailedrecordsofthedistributionofclonesofTrifoliumrepensshowedanaverageofthreetofourdifferentclonesper10x10cm.
Also,detailedmapsofthedistributionofwhiteleafmorphsin1m quadrats.
Dirzo,Rodolfo,andJohnL.Harper.1982.Experimentalstudiesonslugplantinteractions,IV:Theperformanceof
cyanogenicandacyanogenicmorphsofTrifoliumrepensinthefield.JournalofEcology70:119–138.
Acontourmapshowingthedensityofactiveslugsinthefield.
HarperJ.L.1982.Afterdescription.InTheplantcommunityasaworkingmechanism.EditedbyEdwardI.Newman,11–
25.SpecialPublicationoftheBritishEcologicalSociety1.Oxford:Blackwell.
Perhapsmoresoherethaninanyotherpaper,Harperdiscusses(ventshisfrustration)whatheperceivestobesomeofthe
dangersinthethinkingandwritingofecologists.
Harper,JohnL.1983.ADarwinianplantecology.InEvolutionfrommoleculestomen.EditedbyD.Bendall,323–345.
Cambridge,UK:CambridgeUniv.Press.
Anoverviewandanalysisoftheintensiveresearchdonebygraduatestudents(Cahn,Dirzo,LovettDoust,Peters,Sarukhan,
2

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Thorhallsdottir,Trathan,Turkington)andavisitingresearcher(Burdon),inasinglesmall(1ha)fieldofpermanentgrasslandatthe
CollegeFarmatHenfaes,Aber,nearBangorinNorthWales.
Turkington,Roy,andJohnL.Harper.1979.ThegrowthdistributionandneighbourrelationshipsofTrifoliumrepensina
permanentpasture,I:Ordinationpatternandcontact.JournalofEcology67:201–218.
AgeneraldescriptionofthefieldatHenfaes,includingtopography,soils,anddistributionsofindividualspecies.
EcologicalTheory
Harper1977aandHarper1980contendthatplantecologywasdirectionlessandhadlittleincommonintellectuallywithanimal
ecologybecauseitlackedacomparabletheoreticalbase.UsingDobzhansky’sstatement:“Nothinginbiologyhasmeaningexcept
inthelightofevolution”asaspringboard(Dobzhansky1973),HarperreasonedthatifDobzhanskywerecorrect,andifevolutionis
aboutindividualsandtheirdescendants,thatis,fitness,weshouldnotexpecttoreachanyrealecologicalunderstandingfrom
studiesthatfocusatlevelshigherthantheindividual,whethertheydealwithdescriptiveecology,productionecology,orthegross
populationphenomenaofthepopulationbiologist.Whenwestudyapopulation,community,orecosystem,wearestudyingthe
productofthoseindividualsthatleftdescendants.Thisisthelinkbetweendemographyandselection,andthereforebetween
ecologyandevolution,andultimatelythesearethelinksthatgiveplantecologyasoundtheoreticalbasis.Theapplicationof
demographictheorytoplantshasbeenhinderedbecauseofconfusionoverthedefinitionofanindividual.Clonalgrowthinwhich
theproductofazygotegrowstobecomeaseriesofrootedshoots,whichsometimessever,createsadifficulty.Evolutiondepends
onsomezygotesleavingmoredescendantzygotesthanothers.Mostplantsgrowbytheadditionofrepeatedmodulesofstructure
(typicallyashoot,root,andanaxillarybud).Therefore,ademographictheoryofplantsneedstorecognizetwolevelsofpopulation
organization:thegeneticindividualandthemodularunitofstructure(Harper1977b,Harper1980,HarperandWhite1974).
Dobzhansky,T.1973.Nothinginbiologyhasmeaningexceptinthelightofevolution.AmericanBiologyTeacher(March):
125–129.
Thecaseismadethatonlythetheoryofevolutioncanaccountforthediversityoflife,theunityoflife,and,indeed,everything
biologicalthatweobserveontheearth.
Harper,JohnL.1977a.Thecontributionsofterrestrialplantstudiestothedevelopmentofthetheoryofecology.In
Changingscenesinnaturalsciences,1776–1976.EditedbyClydeE.Goulden,139–157.SpecialPublication12.
Philadelphia:AcademyofNaturalSciences.
Thethreetypesofinvestigationthathavedominatedplantecologyareevaluated:descriptive,production,andpopulationecology.
Thepaperhighlightssomeoftheoutstandingquestionsinthethreeareasandtheproblemsthatevolutionarythinkingposesto
ecologicalinterpretation.
Harper,JohnL.1977b.Plantrelationsinpastures.InPlantrelationsinpastures.EditedbyJ.R.Wilson,3–14.Melbourne:
CommonwealthScientificandIndustrialOrganization.
Muchemphasisislaidonunderstandingthebehaviorofindividualssothatwemaybeabletointerpretwhatweknowaboutthe
behaviorofpopulations.Thishasbeendoneatboththeimmediate(proximate)ecologicallevelandatthelongerterm(ultimate)
evolutionarylevel.

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Harper,JohnL.1980.Plantdemographyandecologicaltheory.Oikos35:244–253.
Examplesaregiventoillustratethetheorythataplantisapopulationofpartsthatarebornanddieandthewaysinwhichsucha
theorycanbeappliedtofieldstudies.
Harper,JohnL.,andJamesWhite.1974.Thedemographyofplants.AnnualReviewofEcologyandSystematics5:419–
463.
Thisreviewexaminessomeofthetheoreticalbasesforthedevelopmentofplantdemography(birthanddeathstatistics)and
surveysthecurrentknowledgeofthetopic.
PlantPopulationDynamics
Populationdynamicsdealswiththewaypopulationsareaffectedbybirth,death,immigration,andemigrationrates,thatis,the
vitalratesofapopulationovertime,andithasabroadoverlapwithdemography.Ultimately,suchanalysesofbirthanddeath
statisticsmustfocusattentionontheneedtodiscoverthemechanismsthatcontrol,limit,orregulatepopulationsize.Afewearlier
studieshadbeenconductedbyTamminSweden,RabotnovinRussia,SagarinEngland,andAntonovicsinWales,butitwas
JohnHarperandhisstudentswhobroughtthesubjecttoprominence.Thiseffortbeganwithafourpartserieson“Studiesinthe
dynamicsofplantpopulations”(e.g.,CaversandHarper1967;PutwainandHarper1972),apaper(WhiteandHarper1970),and
review(HarperandWhite1971).
Cavers,PaulB.,andJohnL.Harper.1967.Studiesinthedynamicsofplantpopulations,I:Thefateofseedand
transplantsintroducedintovarioushabitats.JournalofEcology55:59–71.
Demonstratesthatseedsofthreespecieswereabletogerminateinavarietyofhabitatsbutthattheselectionsievewasmuch
strongerattheseedlingthanatthegerminationstage.
Harper,JohnL.,andJamesWhite.1971.Thedynamicsofplantpopulations.InProceedingsoftheAdvancedStudy
InstituteonDynamicsofNumbersinPopulations,Oosterbeek,theNetherlands,September1970.EditedbyJ.denBoer
andG.R.Gradwell,41–63.Wageningen,TheNetherlands:CentreforAgriculturalPublishingandDocumentation.
Aschematicmodelispresentedthatdescribesthebehaviorofplantpopulationsatthesuccessivestages(calledsievesorfilters)
thatregulateplantpopulations:seedbank,environmentalfactors,growthcrowdingandinterference,seedproduction.
Putwain,PhilipD.,andJohnL.Harper.1972.Studiesinthedynamicsofplantpopulations,V:Mechanismsgoverningsex
ratioinRumexacetosaandR.acetosella.JournalofEcology60:113–129.
Demonstratesthatfrequencydependentcontrolofbiasedsexratiosintwospecieswasmoreeffectiveathighdensityandargues
thatthesexesofeachspeciesshowsuchfrequencydependentinteractionbecausetheyoccupyatleastpartlydifferentecological
niches.
White,James,andJohnL.Harper.1970.Correlatedchangesinplantsizeandnumberinplantpopulations.Journalof
Ecology58:467–485.
Thisresearchconfirmsthe3/2powerlawthatrelatesthenumberofsurvivingplantsinapopulationundergoingselfthinningto
theirmeandryweightandextendsthelawtoseveralotherspecies.

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Germination
Onceseedsaredispersedtheircontinuedsurvivaldependsuponlandingonasubstratesuitableforgermination.Manyseedswill
beeatenandotherswilllandonsurfacesnotsuitableforgerminationandmaybeinducedorenforcedintoadormantstate
(Harper1957).Thesoilsurfacemaythenbeconsideredtooperateasafilterorsievedeterminingwhichseedsgerminateto
produceseedlings(HarperandWhite1971,citedunderPlantPopulationDynamics).Theideaofthesoilsurfaceactingasasieve
hasbeenshowninsomedetailbyaseriesofexperimentsbeganinthe1950sbyHarperandhisassociates(Harper,etal.1955)
ontheinfluenceoftheenvironmentonseedandseedlingmortality(see,e.g.,SagarandHarper1960;Harper,etal.1965;
WilliamsandHarper1965;CaversandHarper1966).Thesestudiesdemonstratedthatslightvariationsinthesoilsurfaceimpose
arigorousfilteronsitesinwhichaseedcan,orcannot,germinate.Inaddition,therearespeciesspecificsubtletiesinthe
requirementsforgerminationandseedsizeandshapethatplayamajorroleinfluencingtheprobabilityofgermination(Harper,et
al.1970).
Cavers,PaulB.,andJohnL.Harper.1966.GerminationpolymorphisminRumexcrispusandRumexobtusifolius.Journal
ofEcology54:367–382.
Differencesingerminationresponsewereobservedbetweenseedsofthesamespeciesbutfromdifferenthabitats,different
plants(ofthesamespecies)inthesamehabitat,anddifferentpositionsonthesameplant.Thesurvivalvalueofgermination
polymorphismisdiscussed.
Harper,JohnL.,PhyllisA.Landragin,andJerzyW.Ludwig.1955.Theinfluenceofenvironmentonseedandseedling
mortality,I:Theinfluenceoftimeofplantingonthegerminationofmaize.NewPhytologist54:107–118.
Thisisthefirstofaseriesofeightpapersshowinghowmicroscaleheterogeneityofthesoilsurfaceactsasafilterorsieve
allowingsomeseedstogerminatebutpreventingothersfromdoingso.
Harper,JohnL.1957.Theecologicalsignificanceofdormancyanditsimportanceinweedcontrol.InProceedingsofthe
IVthInternationalCongressofCropProtection,Hamburg1990.EditedbyJohannesKrause,415–420.Brunswick,
Germany:InternationalCongressofCropProtection.
Seeddormancymaintainsareserveofseedsthatarenotexposedtohazardsfacedbythegrowingplantandapopulationof
genotypespermittinganoverlapofgenerationsandabufferingofapopulationagainsttemporaryselectiveforces.
Harper,JohnL.,PeterH.Lovell,andKeithG.Moore.1970.Theshapesandsizesofseeds.AnnualReviewofEcologyand
Systematics1:327–356.
Aclassicwithmorethan1,000citations,inthisreviewtheauthorsarguethatseedsizesandshapesarebothcomplexadaptive
compromises;seedsizeisacompromisewithseednumber,andseedshapesarecompromisesbetweentheformsmostefficient
fordispersal,landing,andseedlingestablishment.
Harper,JohnL.,andJamesWhite.1971.Thedynamicsofplantpopulations.InProceedingsoftheAdvancedStudy
InstituteonDynamicsofNumbersinPopulations,Oosterbeek,theNetherlands,September1970.EditedbyJ.denBoer
andG.R.Gradwell,41–63.Wageningen,TheNetherlands:CentreforAgriculturalPublishingandDocumentation.
Thesievesorfiltersthatregulateplantpopulationsoperateatallstagesintheplantlifecycle;themostriskystages,thatis,when

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thefiltersaremostrigorous,areduringgerminationandestablishment.
Harper,JohnL.,J.TrevorWilliams,andGeoffR.Sagar.1965.Thebehaviourofseedsinsoil,I:Theheterogeneityofsoil
surfacesanditsroleindeterminingtheestablishmentofplantsfromseed.JournalofEcology53:273–286.
Thesocalledgraveyardexperiment.Onekeymessageisthedangerofdrawingconclusionsfromasinglestudy.Harper
particularlylikedthisexperimentbecauseitwasusedby“atleast20ecologyclassesinuniversitiesthroughouttheworldbecause
itwassoeasytodo—butIoftenreceivedletterstellingmethatsomeone’sparticularclassobtainedadifferentresultthanwhatwe
published.Ofcourse!Thatwasoneofthemainpointsofthestudy”(personalcommunication).
Sagar,GeoffR.,andJohnL.Harper.1960.Factorsaffectingthegerminationandearlyestablishmentofplantains
(Plantagolanceolata,P.mediaandP.major).InThebiologyofweeds.ByGeoffR.SagarandJohnL.Harper,236–245.
BritishEcologicalSocietySymposium1.Oxford:Blackwell.
Whenseedsandseedlingsofthethreespeciesweresowninvarioushabitats,thephasesofgerminationandearlyseedlinglife
werecriticalfortheestablishmentofaspecies.Onlyrarelywasitpossibleeithertointroduceaspeciesintoahabitatortoincrease
itsdensitybysowingseeds
Williams,J.Trevor,andJohnL.Harper.1965.Seedpolymorphismandgermination,I:Theinfluenceofnitratesandlow
temperaturesonthegerminationofChenopodiumalbum.WeedResearch5:141–150.
Chenopodiumalbumispolymorphicforseedshapeandcolorandfourcategoriescanberecognized.Allfourtypesmaybeborne
byoneplantandtheydifferingerminationrequirements.
Regulation
Populationregulationisafundamentalprocessrelatedtomostphenomenainecologyandunderliesmostothertopicsofinterest,
suchasinterference(competition)andthestructureanddynamicsofpopulationsandcommunities.Innaturalplantpopulations
numbersarekeptwithincertainboundsbydensitydependentforces.Whenpopulationdensityishigh,thepopulation(of
individualsoroframets)willlikelydecrease,whereasincreasestendtooccurwhenpopulationdensitiesarelow.Harperfirst
discussedplantpopulationregulationintheBiologyofWeeds(Harper1960,citedunderBooks:TheBiologyofWeeds)
SymposiumtotheBritishEcologicalSociety,andtheninmoredetailin“Theregulationofnumbersandmassinplantpopulations”
(Harper1968;alsocitedunderBackgroundDevelopment:UniversityCollegeofNorthWales(UCNW),Bangor).Regulationisalso
acentralissueinthehighlycitedpapersofKaysandHarper1974andWatkinsonandHarper1978.
Harper,JohnL.1968.Theregulationofnumbersandmassinplantpopulations.InPopulationbiologyandevolution.
EditedbyRichardC.Lewontin,139–158.NewYork:SyracuseUniv.Press.
Themainthemeofthispaperisthatanimalpopulationtheorycannotalwaysbeappliedtoplantpopulationsbecauseplantshave
suspendedanimation(dormancy),haveenormousindividualplasticity(becauseoftheirmodularstructureandclonalgrowth),and
arestronglyinfluencedbyneighborsbecausetheycan’trunawaylikeanimalscan.
Kays,Stanley,andJohnL.Harper.1974.Theregulationofplantandtillerdensityinagrasssward.JournalofEcology
62:97–105.

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Yieldperunitarearapidlybecomesindependentofthenumberofplantspresentandisdominatedbytheavailabilityofresources.
Overaperiodoftwentyweekspopulationsconvergedtowardatillerdensityandameantillerweightthatwasindependentofthe
thirtyfoldrangeinseeddensities.
Watkinson,AndrewR.,andJohnL.Harper.1978.Thedemographyofasandduneannual:Vulpiafasciculate,I:Natural
regulationofpopulations.JournalofEcology66:15–33.
Basedondatacollectedfromfrequentmonitoringandamanipulativefieldexperiment,thispaperpresentsamodelthatdescribes
thepopulationdynamicsofasandduneannualintermsofthedensitydependentregulationofspikeletnumberandthedensity
independentmortalityofindividuals.
Competition
Harperandhiscolleagueswereperplexedbythediversityofnaturalvegetationandwhysomanyspeciescouldcoexist,often
closelyrelatedspeciesespeciallyinlightofbothGause’scompetitiveexclusionprincipleandbecauseDarwinarguedthatthe
severestcompetitionshouldcomefromthemostsimilarspecies.CompetitionamongplantswasforemostinHarper’sthinkingand
hecontendedthatchapter3ofTheOriginofSpecies(“TheStruggleforExistence”)wasthebestwritingeveroncompetition.In
Harper’spresentationatthesymposiumoftheSocietyforExperimentalBiology(Harper1961),helistssevenmajorproblemsin
biologythatrequireinformationonthemannerandeffectsofinterference(competition)betweenorganismsfortheirsolution,and
inhispresentationtotheEleventhInternationalCongressofGeneticshedescribesindetailthenatureandconsequencesof
interferenceamongplants(Harper1964).Thistheme,astrugglebetweenneighborsforlimitingresources,isprominentinHarper
1967(citedunderBackgroundDevelopment:UniversityCollegeofNorthWales(UCNW),BangorandEvolutionaryEcology),
PresidentialaddresstotheBritishEcologicalSocietyandsixofthetwentyfourchaptersofHarper1977(citedunderBooks:
PopulationBiologyofPlants)aredevotedtotheeffectsoftheproximityofneighbors.Itisnosurprisethatmuchoftheresearch
fromHarper’slabdealtwithcompetition,themosthighlycitedbeingHarperandChancellor1959;SagarandHarper1961;
ClatworthyandHarper1962;Obeid,etal.1967;MackandHarper1977;andSchmidandHarper1985.
Clatworthy,JohnN.,andJohnL.Harper.1962.Thecomparativebiologyofcloselyrelatedspecieslivinginthesame
area,V:InterandintraspecificinterferencewithinculturesofLemnaspp.andSalvinianatans.JournalofExperimental
Botany13:307–324.
Threespeciesoffloatingpondweed(Lemna)andafloatingfern(Salvinia)weregrowninpurecultureandinmixturesathighand
lowdensities.Thesuccessofaspeciesinmixturecouldnotbepredictedfromtheparametersofgrowthinpureculture.
Harper,JohnL.1961.Approachestothestudyofplantcompetition.InMechanismsinbiologicalcompetition.Editedby
theSocietyforExperimentalBiology,1–39.SymposiaoftheSocietyforExperimentalBiology15.NewYork:Academic
Press.
Duetotheconfusionaboutthemeaningoftheword“competition,”Harperproposedreplacingitwith“interference”tobeused“as
ablanketwordtodescribethosehardshipswhicharecausedbytheproximityofneighbours(usuallyotherorganismsfeedingat
thesametrophiclevel)”(p.1).
Harper,JohnL.1964.Thenatureandconsequenceofinterferenceamongstplants.InGeneticstoday:Proceedingsofthe
XIthInternationalCongressofGenetics,TheHague,theNetherlands,September1963.Vol.2.EditedbyS.J.Geerts,465–
482.Oxford:Pergamon.

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Thispaperfocusesattentiononthereactionofaplanttoitsneighborsasacritical,oftenthemostcritical,partoftheautecologyof
aspeciesandtosuggestthatthistypeofstudyhasaunifyingfunctioninthescienceofplantecology.
Harper,JohnL.,andA.PatriciaChancellor.1959.Thecomparativebiologyofcloselyrelatedspecieslivinginthesame
area,IV:Rumex:Interferencebetweenindividualsinpopulationsofoneandtwospecies.JournalofEcology47:679–695.
PotexperimentsweremadetodeterminethenatureoftheinterferencebetweenplantsoffivespeciesofRumexundercontrolled
conditionsofsowingdensity,speciesmixtures,waterregime,andsoiltype.Therewerestrongresponsestowaterregimeandsoil
typeandfourofthespeciesshowedthesamegeneralpatternofresponse.
Mack,RichardN.,andJohnL.Harper.1977.Interferenceinduneannuals:Spatialpatternandneighbourhoodeffects.
JournalofEcology65:345–363.
Thiswasoneofthefirststudiestoshowthattheoutcomeofinterferencewasinfluencedbytheidentityandsizeofaplant’s
neighborsandhowthoseneighborswerearrangedaroundthefocalplants.Thepaperwaslistedas“oneofthetop100most
influentialpaperspublishedbytheBritishEcologicalSociety(1913–2012)”.
Obeid,Mohammed,DavidMachin,andJohnL.Harper.1967.Influenceofdensityonplanttoplantvariationinfiberflax
LinumusitatissimumL.CropScience7:471–473.
Inthisstudy,plantsdevelopedalognormalfrequencydistributionofdryweightwithageandincreaseddensity.Otherplanttraits,
suchascapsulenumberperplantandmeanseednumberpercapsuleandindividualseedweight,developdifferentfrequency
distributions.Thisemphasizeshowplanttoplantvariationitselfchangeswithdensity.
Sagar,GeoffR.,andJohnL.Harper.1961.ControlledinterferencewithnaturalpopulationsofPlantagolanceolata,P.
majorandP.minor.WeedResearch1:163–176.
Theresultsofthisexperimentsuggestthatgrassesplayanimportantroleindeterminingthepresenceorabsenceofparticular
Plantagospeciesandalsoincontrollingthesizeoftheexistingplantainpopulations.
Schmid,Bernhard,andJohnL.Harper.1985.Clonalgrowthingrasslandperennials,I:Densityandpatterndependent
competitionbetweenplantswithdifferentgrowthforms.JournalofEcology73:793–808.
Clonesofaphalanx(Bellis)andguerrilla(Prunella)growthformwereusedtoinvestigatecompetitionbetweenandwithinclones
andbetweenspecies.Differencesinresponsewerecausedbythedifferencesingrowthformofthetwospecies.
ReproductiveStrategies
AlthoughHarperhadwrittenaboutthereproductivebiologyofBritishpoppiesin1966,itwasnotuntiltheDarwinianapproach
(Harper1967;citedunderBackgroundDevelopment:UniversityCollegeofNorthWales(UCNW),BangorandEvolutionary
Ecology)thatheexploredthetopicindetail.Hepresentsthereaderwithsevenresearchquestions.Thewayinwhichanorganism
allocatesitsresourcesmayhaveprofoundecologicalconsequences.Forexample,anyplantshouldallocateresourcestoleaving
offspring(seedoutputandrametproduction)(Harper,etal.1970),tocompetitiveability(heightgrowth,leaves,stems,rootsetc.),
andtopredatoravoidance(unpalatablestructures,suchasdefensivechemicalsorspines).Harperwasparticularlyinterestedin
thestrategyofreproductionandwhenhewaswritingin1967thisbranchofplantecologywasvirtuallyunstudied.Thissubjectis

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studiedinOgdenandHarper1970andBazzaz,etal.1979.
Bazzaz,FakhriA.,RogerW.Carlson,andJohnL.Harper.1979.Contributiontoreproductiveeffortbyphotosynthesisof
flowersandfruits.Nature279:554–555.
Theauthorschallengesomeoftheassumptionsmadeinstudiesofreproductiveallocationandparticularlytheconventional
estimationofreproductiveeffort.Thepaperreportsananalysisofthecarbonbudgetofreproductionforfifteentemperate
deciduoustrees.
Harper,JohnL.,PeterH.Lovell,andKeithG.Moore.1970.Theshapesandsizesofseeds.AnnualReviewofEcologyand
Systematics1:327–356.
Table1inthispapersummarizestheproportionofnetannualassimilationthatisinvolvedinreproductiveeffort.Itincludesgrain
cropsandherbaceousperennialandannualplants.Table2showstherangesinseedweight(uptotenordersofmagnitude).
Ogden,John,andJohnL.Harper.1970.Thereproductivestrategyofhigherplants,I:Theconceptofstrategywith
specialreferencetoSeneciovulgarisL.JournalofEcology58:681–698.
Thispaperdescribesthepartitioningofdrymatterandenergythroughoutthelifecycleofdifferentplantspeciesandconsidersthe
conceptsofenergyallocation,strategyandtactics,andthemeasurementof“reproductiveeffort,”primarilyinrelationtoannual
composites.
Demography
Demographydescribesandattemptstoexplainnumbersandchangesinnumbersoforganisms—populationflux,agedistribution,
ageatdeath,survivorship,lifeexpectancy—andithasmuchincommonwithpopulationdynamics.HarperandWhite1974(cited
underEcologicalTheory)andHarper1978arguethatifplantecologyweretobebroughtwithinthehardpredictivesciences,we
couldnotavoidpayingmuchgreaterattentiontodemographicanalysis.DemographicstudyofthetypeenvisionedbyHarperand
Whitefocusesattentiononthelifespanofindividualsandonthetimeandcauseofdeath.Suchdatacanbeobtainedonlyby
detailedobservationsofindividualplantsthataremarkedforrepeatedobservations,suchasinstudiesthatincludeSarukhánand
Harper1973onthreespeciesofRanunculus;WatkinsonandHarper1978onVulpiafasciculata;Noble,etal.1979onCarex
arenaria;andLovettDoust1981onRanunculusrepens.
Harper,JohnL.1978.Thedemographyofplantswithclonalgrowth.InStructureandfunctioningofplantpopulations.
EditedbyA.H.J.FreysenandJ.W.Woldendorp,27–48.Amsterdam:NorthHolland.
Evolutionhappensbecausesomeindividuals,withcertaingenotypes,leavemoredescendantsthanothers.However,higher
plantsexpressthegenotypeinrepeatedmodularunitswithinanindividual,andtheyexpresstheirresponsetoenvironmental
stressmainlybyalteringthenumberofmodularunits.
LovettDoust,Lesley.1981.Populationdynamicsandlocalspecializationinaclonalperennial(Ranunculusrepens),I:
Thedynamicsoframetsincontrastinghabitats.JournalofEcology69:743–755.
ThedemographyoframetswasmonitoredintwoadjacentpopulationsoftheclonalperennialRanunculusrepensinpark
grasslandandinmixeddeciduouswoodland.Thetermsphalanxandguerrillaareintroducedtodescribethedifferentpatternsof

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clonalgrowth.Therearetwootherpapersinthisseries:II:“TheDynamicsofLeaves,andaReciprocalTransplantReplant
Experiment,”JournalofEcology69(1981):757–768;andIII:“ResponsestoLightandNutrientSupply,”JournalofEcology75
(1987):555–568.
Noble,JamesC.,AdrianD.Bell,andJohnL.Harper.1979.Thepopulationbiologyofplantswithclonalgrowth,I:
MorphologyandstructuraldemographyofCarexarenaria.JournalofEcology67:983–1008.
Thismanipulativefieldstudymonitoredthestructuraldemographyofarhizomatousspeciesintwodunesystems.Plotswere
establishedinthemature,senile,andslackphasesofnaturalpopulations;halftheplotsreceivedamassivenutrientapplicationof
NPKfertilizer.Theshootpopulationswithinpermanentquadratsweremappedatfrequentintervals.
Sarukhán,José,andJohnL.Harper.1973.Studiesonplantdemography:RanunculusrepensL.,R.bulbosusL.andR.
acrisL.,I:Populationfluxandsurvivorship.JournalofEcology61:675–716.
Arguablythemostdetailedplantdemographicstudyeverundertaken.Acensusofallplants,includingseedlings,ofthreespecies
ofRanunculus(morethan9,000individuals)wastakenatintervalsofafewweeksover2.5yearsinagrazedpasture.Thethree
specieshadquitedifferentlifecycles,thatis,solutionstosurvivalinthisonepasture.Thispaperwaslistedas“oneofthetop100
mostinfluentialpaperspublishedbytheBritishEcologicalSociety(1913–2012).”
Watkinson,AndrewR.,andJohnL.Harper.1978.Thedemographyofasandduneannual:Vulpiafasciculate,I:The
naturalregulationofpopulations.JournalofEcology66:15–33.
Permanentquadratsweremappedregularlyontwosanddunesystemstoobtaindataonthefatesofseedlingsandthe
reproductiveperformanceofeachindividualplant.Naturaldensitiesoftheplantswerealsomanipulatedtoassesstheroleof
densityinregulatingthepopulations.
DemographicApproachtoPlantForm(Plasticity)
Someoftheearlieststudiesonplantdemographysaylessaboutthenumberofindividualsinapopulationthanaboutthenumber
ofunitsormoduleswithinasingleplant.Thenumberofunitsdeterminesthesizeoftheplant,andtheirarrangementdetermines
plantform.Plantsareextremelyvariableinsizeandgrowthform(plasticity),andthisfeaturealongwithclonalgrowth(vegetative
reproduction)hasseriouslyhinderedthedevelopmentofplantdemography.Manyplantsgrowbyproducingrootedbranches,for
example,strawberry,whiteclover(Trifoliumrepens),somebuttercups(Ranunculus),brackenfern(Pteridiumaquilinum),and
tremblingaspen(Populustremuloides).Thedemographerhastodecideonhowtodefineanindividual,whichcouldbeeitherthe
geneticindividual,thatis,everythingthatgrewfromasingleseed,ortheunitofstructurethatformsashootaboveground.The
definitionofthesetwointerlinkedproblemsmadepossiblearigorousdevelopmentofplantpopulationbiology,ingeneral,andof
demographyandpopulationdynamics,inparticular(HarperandBell1979,Harper1981).Inessence,thegeneticindividual
maybeconsideredasapopulationofparts(BazzazandHarper1977,White1979)inwhichthepartsthemselveshavebirthand
deathstatisticsseparatefromthebirthanddeathsofgeneticindividualsinthepopulation.HarperandWhite1974andHarper
1980contendthatanunderstandingofthedemographyofthepartsisthestartingpointforsomeaspectsofthedemographyof
separateindividualsandHarper1978(citedunderDemography)andSackville,etal.1987havedrawnparticularattentionto
plantswithclonalgrowth.Viewedinthisway,growthinsuchanorganismisitselfademographicprocess(Harper1980,cited
underEcologicalTheory).Anyeffectivetheoryofplantdemographymusttakeintoaccountthetwolevelsatwhichbirthanddeath
occurs:thebirthanddeathofgeneticindividualsandthebirthanddeathofthemodulesorunitsthatmakeupthegenetic
individual.Maillette1982appliestheideatothepopulationofbudsinsilverbirch.

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Bazzaz,F.A.,andJohnL.Harper.1977.DemographicanalysisofgrowthofLinumusitatissimum.NewPhytologist
78:193–208.
Thisstudyshowsthattheapplicationoflifetableandotherdemographicanalysestoleafbirthanddeathisfeasibleandpermits
aninterpretationofplantresponsetoenvironmentalfactorsatamoresophisticatedlevelthanispossiblefromclassicalgrowth
analysis.
Harper,JohnL.1981.Theconceptofpopulationinmodularorganisms.InTheoreticalecology.2ded.EditedbyRobert
M.May,53–77.Oxford:Blackwell.
ThisisprobablyHarper’smostexhaustivetreatmentofthemodularconstructionofplants,clonalgrowth,andplasticity,andwhy
anytheoryofplantpopulationdynamicsmusttakeintoaccountboththedynamicsofindividualgenotypes(genets)andthe
dynamicsofmodules(ramets)withinagenotype.
Harper,JohnL.,andAdrianD.Bell.1979.Thepopulationdynamicsofgrowthforminorganismswithmodular
construction.InPopulationsdynamics:The20thsymposiumoftheBritishEcologicalSociety,London1978.Editedby
R.M.Anderson,D.Turner,andL.R.Taylor,29–52.Oxford:Blackwell.
Plantsarenotdifferentfromanimals;rather,organismswithmodulargrowth(mostlyplantsbutalsosomeanimalssuchasObelia,
corals,Hydra)aredifferentfromthosewithunitaryconstruction(mostlyanimals).Thepaperalsomakesthecasethat“form”isa
resultofdemographicprocesses.
Harper,JohnL.,andJamesWhite.1974.Thedemographyofplants.AnnualReviewofEcologyandSystematics5:419–
463.
Presentstheviewthatanygeneraltheoryofplantdemographythatfailstoconsiderbothlevelsofdemography,thegenetic
individual(thegenet)andthemodulesthatmakeupthatindividualgenet,isseriouslyincomplete.Arecognitionofthisdualism
allowstheplantdemographertodealwithclonalgrowthandplasticity.
Maillette,Lucie.1982.Structuraldynamicsofsilverbirch,I:Thefatesofbuds.JournalofAppliedEcology19:203–218.
Thisstudyconsidersthecrownofatreeasapopulationofrepeatedunits(buds,leaves,shoots,flowers)withdemographic
properties.Theauthoranalyzesthestructuraldynamicsofthegrowthofsilverbirch(Betulapendula)usingdemographic
techniques.Thesecondpaperinthisseriesis:“II:AMatrixModeloftheBudPopulation,”JournalofAppliedEcology19(1982):
219–223.
Sackville,Hamilton,N.Ruaraidh,BernhardSchmid,andJohnL.Harper.1987.Lifehistoryconceptsandthepopulation
biologyofclonalorganisms.ProceedingsoftheRoyalSocietyofLondon,BiologicalSciences232:35–57.
Amodelispresentedofasizestructuredpopulationofgeneticindividuals(genets),inwhicheachgenetconsistsofanage
structuredmetapopulationofmodules.ThepredictedresponsestorandKselectiondiffermarkedlyfromthosepredictedfor
unitaryorganisms:rselectionmayfavorclonalgrowthwithnoreproduction,whereasKselectionfavorsgreaterreproduction.
White,James.1979.Theplantasametapopulation.AnnualReviewofEcologyandSystematics10:109–145.
Retainsthewordpopulationforacollectionofgeneticallydistinctindividualsandproposesmetapopulationforthecollectionof

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geneticallyidenticalmoduleswithinaplant.Thisreviewcollatesadiffuseliteratureontheplantasametapopulation.Historical
aspectsaretreatedfirstfollowedbyareviewofmodernstudies.Availableonlineforpurchase.
Books
JohnHarperpublishedonemajortextbook,PopulationBiologyofPlants(Harper1977),coauthoredtwoverysuccessful
undergraduatetextbooks,andeditedorcoeditedthreevolumesthatfeaturemultipleauthors.
PopulationBiologyofPlants
PopulationBiologyofPlants,Harper’s892pagetome,hasbeenaffectionatelyknownas“ThegospelaccordingtoJohn.”
Throughoutthisbook,HarperemphasizestheimportanceofDarwiniannaturalselectionandthenecessityofaccuratecensus
dataandexperimentstoaddressquestionsatboththepopulationandcommunitylevelsoforganization.Mostchapterspose
numerousquestions,manyofwhichremaintobeanswered.Atleastninedifferentecologicaljournalsreviewedthebookandtoa
largeextenttheywereglowinglypositive(Woodell1977,Mooney1978,vanderMeijden1978),butsomereviewspointedout
weakcoverageofcertaintopics(vanderMeijden)especiallyphysiologyandgenetics(Solbrig1979).Althoughpublishedin1977it
isstillarichsourceofinformationandideas.Harpernotedwithirritationthatthebook(whichasofFebruary2015hasmorethan
11,000citations)wasoftencitedcarelesslybymanyresearchersmerelytosupportpoorlyformedideas.Throughoutthevolume,
Harperpointsoutwaysinwhichplantandanimalpopulationsaresimilaranddifferent.Intheprefacetothe2010edition,printed
thirtyoneyearsaftertheoriginalpublication,Sarukhán,Dirzo,andFrancowritethatHarper’sbook“linkedtheconceptualand
theoreticaldevelopmentsinpopulationecology,mostlyderivedfromthestudyofanimals,withfieldobservationsandexperimental
evidenceofpopulationregulationandlifehistoryevolutioninplants.Thefieldofpopulationbiologywasalreadywellestablishedin
the1960salthoughwithaclearzoocentricemphasis,however,itisbecauseofHarper’sworkthatthefieldexperiencedaveritable
explosion,reachedmaturityandbecameamainstreamscientificendeavourworldwide.Thisfieldissovastnowthatitwouldbe
pointless,ifnotimpossible,forsomeonetosummariseit.ItispreciselybecauseofthisthatPBP[PopulationBiologyofPlants]is
asrelevantnowasitwasin1977.JohnHarper’sstyleofhighlightingunansweredquestionsandthelimitationsofboththeoryand
empiricalevidenceservedandstillservesasfoundationforresearchagendasworldwide.Muchremainstobedoneinthisfield
andthisalonemakesPBPanessentialelementinthelibraryofeverystudent/researcherofpopulationbiology,whetherinterested
inplantsoranimals.”
Harper,JohnL.1977.Populationbiologyofplants.London:AcademicPress.
This892pagevolumehadaprofoundimpactonthesubjectandbroughttogetherforthefirsttimeamajorsynthesisofthecurrent
stateofknowledgeofthepopulationbiologyofplants.Thetextcoverstheentirerangeoftopicsinplantpopulationbiology,
includingdispersal,dormancy,germination,recruitment,interference,herbivory,predation,naturaldynamics,reproduction,
growth,communitystructure,diversity,andnaturalselection.
Mooney,HaroldA.1978.BookreviewofPopulationbiologyofplants.Science199:675–676.
HaroldMooneywrites:“JohnHarperhasmadeenormouscontributionstoourunderstandingofplantbiology.Harper’sinnovative
ideashaveledtoawholeschoolofthoughtandresearchthatisspreadfarbeyondhishomeUniversity”(p.675).
Solbrig,Otto.1979.PopulationbiologyofplantsbyJ.L.Harper.JournalofEcology67.1:386–388.
SolbrigprovidesthemostcriticalofthereviewsofHarper1977.

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vanderMeijden,Eddy.1978.PopulationbiologyofplantsbyJohnL.Harper.Vegetatio38.1:61–62.
AlthoughvanderMeijdenidentifiessomeshortcomingsinthetext,hisreviewislargelycomplimentary.Availableonline.
Woodell,StanR.J.1977.Bestkindofnaturalhistory.Nature270.5637:545.
Woodellnotesthat“thereareenoughideas[inthetextbook]tokeepseveralworkersbusyforalifetime”(p.545).
Ecology:FromIndividualstoEcosystemsandEssentialsofEcology
Itisunusualforanundergraduatetextbooktohavemorethan1,200citationsintheprimaryecologicalliterature.Suchisthe
qualityofbothofthesetextbooks,writtenincollaborationwithMichaelBegon(Liverpool)andColinTownsend(Otago,New
Zealand).Thefirstvolumewaspublishedin1986,isnowinitsfourthedition(Begon,etal.2006),andhasservedasthestandard
undergraduateecologytextbookformorethantwentyyears.Thebookseparatesitselffromothertextbooks,intypicalHarperian
fashion,byrecognitionthatecologyisaconstantlyevolvingsubjectwithitsownuncertaintiesandcontroversies;thus,readersare
forcedtothinkaboutandevaluatealternativeideasratherthanproviding‘theanswer.”Inreviewingthebook,RobertSmith
(Nature319[1986]:809)writes:“Thefreshnessofapproachandbreadthanddepthofcoveragemakemostoftheopposition
[undergraduateecologytextbooks]seemratherstaleandrestricteddietbycomparison...andallteachersofecologyshould
samplethisnouvellecuisine.”Bothofthesetextbookshavehadaprofoundinfluenceonagenerationofundergraduatesand
variouseditionshavebeentranslatedintomanylanguages,includingGerman,Spanish,Russian,Japanese,and,morerecently,
Chinese,Korean,andPortuguese.In2007theauthorsreceivedaLifetimeAchievementAwardfromtheBritishEcological
Society.
Begon,Michael,ColinR.Townsend,andJohnL.Harper.2006.Ecology:Fromindividualstoecosystems.4thed.Oxford:
Blackwell.
Thisundergraduatetextbookhasservedasthestandardadvancedtextbookinecologyfornearlytwentyyears.Itis
comprehensiveincoverage,exploringecologicalconceptswithrelevantfieldandlaboratorystudies.FormerlyknownasEcology:
Individuals,PopulationsandCommunities.Originallypublishedin1986.
Townsend,ColinR.,JohnL.Harper,andMichaelBegon.2008.Essentialsofecology.3ded.Oxford:Blackwell.
ThistextbookalongwithitslargercompaniontextofBegon,etal.2006servedasforerunnersinthescienceofecologytoa
generationofundergraduatestudents.Originallypublishedin1999.
TheBiologyofWeeds
JohnHarper’supbringingonafarmandagriculturalbackgroundareclearlyreflectedinthesubjectsusedinmuchofhisresearch
—cropplants,grasses,andweeds.Duringthe1950sHarperandhiscolleaguesbeganaseriesofstudiesontheinfluenceofthe
environmentonseedandseedlingmortalityand,from1953to1960,theygaveincreasingattentiontothestudyofweeds.The
naturaldevelopmentfromtheseearlystudiesultimatelyledtotheholdingofthefirstsymposiumoftheBritishEcologicalSociety,
whichwastitledtheBiologyofWeeds;hewaseditorofthebook(Harper1960)thatstemmedfromthisconference.

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Harper,JohnL.,ed.1960.Thebiologyofweeds.SymposiumoftheBritishEcologicalSociety1.Oxford:Blackwell.
ThisbookincludestheproceedingsofthefirstsymposiumheldbytheBritishEcologicalSociety.Itconsistsoftwentyfourchapters
(papers)onallaspectsofweedbiology,includinghistory,ecology,taxonomy,germination,dormancy,dispersal,andcompetition
writtenbymanyofthemostnotableweedbiologistsatthattime.
OtherBooks
Harperwasalsocoeditoroftwoothervolumeswithmultipleauthors:Chaloner,etal.1991andSilvertown,etal.1997.
Chaloner,WilliamG.,JohnL.Harper,andJohnH.Lawton,eds.1991.Theevolutionaryinteractionofanimalsandplants.
PhilosophicalTransactionsoftheRoyalSocietyofLondon,BiologicalSciences333.London:RoyalSociety.
Thisisaseriesoffourteenpaperswrittenbyleadingecologists.Topicsrangefromfossilevidenceforplantarthropodinteractions,
pollination,andherbivorytoevolutionofleafshape,plantsecondarychemicaldiversity,insectmorphology,andcellulosedigestion
ininsects.Eachchapterisfollowedbyadiscussion,andthefinalchapteris“TheCroonianLecture”byTonyBradshaw.
Silvertown,Jonathan,MiguelFranco,andJohnL.Harper,eds.1997.Plantlifehistories:Ecology,phylogenyand
evolution.Cambridge,UK:CambridgeUniv.Press.
Thisbookexaminesthephylogeneticrelationshipbetweenplantlifehistorytraitsandprovidesanimportantsynthesisofthinking
onamultifacetedproblem.Thefinalsectionofthebookfocusesoninteractionsbetweenplantsandcompetitorsandherbivores
andmicrobialsymbionts,recognizingthattheseinteractionsmayhaveanancientevolutionaryhistory.
Legacy
JohnHarper’slegacyincludeshisownaccomplishmentsandrecognitioninthefieldofplantpopulationbiology(seethesection
AwardsandService),hisparticipationinserviceonvariousadvisoryboards,andwhathesometimescalledhisacademicprogeny
—hewasproudofhisstudents.Hislegacyalsoincludesgemsofwisdomforwhichhewillberemembered,suchashispleafor
clarityandprecisionandhisdistasteforfuzzythinking.Harperwasalsoproudofthelegacyproducedbyhismanystudents.He
leftaprofoundecologicalfootprint,especiallyinMexico,theUnitedStates,Canada,andpartsofEurope(Franco,etal.2009).
Twoofhisformerstudents,JoséSarukhánandRodolfoDirzo,wereelectedforeignassociatesoftheUSNationalAcademy,and
SarukhánwasalsoelectedaforeignmemberoftheRoyalSociety.LesleyClegg(nowLesleyLovettDoust)servedasprovostand
vicepresidentforacademicaffairsatMichiganTechnicalUniversityinHoughton,Michigan,until2009,beforebeingappointed
presidentandvicechancellorofNipissingUniversityinNorthBay,Ontario,wheresheservedfrom2009to2012.Foranumberof
years,JoséSarukhánwaspresidentofthelargestuniversityintheworld(UNAM)inMexicoCity.ManyofJohnHarper’sstudents
becamemajorinfluencesintheirownright(seethesectionBiography).Twentyeightformercollaboratorsrepresentingeight
nationalitiesfromninecountriescontributedtoHarper’sfestschrift(White1985)ontheoccasionofhissixtiethbirthday.Individuals
representingmorethantwentynationalitiesparticipatedasmembersofHarper’slabeitherasstudentsorasvisitors,andeighteen
ofhisformerstudentsholdfacultypositionsinuniversitiesaroundtheworld.
Franco,Miguel,JoséSarukhán,andRodolfoDirzo.2009.ADarwinianplantecologist,JohnLanderHarperCBEFRS,
1925–2009.InMemoriesofJohnL.Harper:Aremembrancebyhisfriends,students,andcolleagues.2ded.Editedby

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GlennR.Matlack,98–100.Bangor,UK:SPB.
ThisonlineresourcewrittenbythreeofHarper’sgraduatestudentsprovidesanoverviewofHarper’sacademiccareerand
influenceandhowthisinfluencehasspreadtotouchsuccessivegenerationsofMexicanstudents,contributingtothestudyand
conservationofMexico’sbiodiversity.
White,James,ed.1985.Studiesofplantdemography:AfestschriftforJohnL.Harper.London:AcademicPress.
Avolumeoftwentyfourchaptersonplantdemography,writtenbyformerstudentsandcollaborators,compiledtomarkthesixtieth
birthdayofJohnHarper.
CollaborationsandMentorship
Harper’scareerisnoteworthyforhislegacyasamentor.Harperpublishedmanysingleauthoredpapersandtypicallycoauthored
(althoughnotalways)atleastonepaperwitheachofhisstudentsandvisitors.AreviewofHarper’spublicationsdemonstratesthe
enormousmentoringhebroughttogenerationsofstudents,doctoralgraduates,andvisitors.ManystudentsleftHarper’slabto
becomemajorinfluencesintheirownright.TomarkHarper’ssixtiethbirthday,JamesWhitecoordinatedproductionofafestschrift
thatincludestwentyfourchapterswrittenbytwentyeightformercollaboratorsrepresentingeightnationalitiesfromninecountries
(White1985).IndividualsrepresentingmorethantwentynationalitiesweremembersofHarper’slabeitherasstudentsoras
visitors,andeighteenofhisformerstudentsholdfacultypositionsinuniversitiesaroundtheworld.Suchistheglobalinfluenceof
theuniquelyHarperianapproachtoplantecology,which,ofcourse,isalsoamajoraspectofhislegacy.
White,James,ed.1985.Studiesofplantdemography:AfestschriftforJohnL.Harper.London:AcademicPress.
Avolumeoftwentyfourchaptersonplantdemography,writtenbyformerstudentsandcollaborators,compiledtomarkthesixtieth
birthdayofJohnHarper.
ClarityandPrecision
Harperwasknownforhisrapiersharpwitandequallysharpintellect.Buthisinsistenceonclarityandprecisioninthinkingand
writingconstitutesperhapshisgreatestintellectualtrait.Harperwasruthlessincombattingfuzzythinking,andhadabhorreduseof
sloppyterminology.InHarper1982(citedunderExperimentalEcology),heattacksusageofthewordsstress,strategy,and
adaptation.InBegon,etal.2006(citedunderBooks:Ecology:FromIndividualstoEcosystemsandEssentialsofEcology),andin
Townsend,etal.2008(citedunderBooks:Ecology:FromIndividualstoEcosystemsandEssentialsofEcology),theword
adaptationisdismissedintheearlypagesandapparentlynotusedagain.Heparticularlydislikedthetermvegetative
reproduction:“ifatreesspreadsverticallywecallitgrowth,butifacloverspreadslaterallywecallitreproduction—nonsense”
(personalcommunication).Heloathedthewordcompetition,oratleastthesloppywayinwhichthetermhadbeenusedby
ecologists,andpreferredinsteadthemoregeneralterminterference“asablanketwordtodescribethosehardshipswhichare
causedbytheproximityofneighbours(usuallyotherorganismsfeedingatthesametrophiclevel)”(Harper1961,p.1,citedunder
BackgroundDevelopment:Oxford,DepartmentofAgriculture).Whilethewordinterferenceappearsinthetitlesofeightpapers
rangingfromHarperandChancellor1959(citedunderCompetition)toMackandHarper1977(citedunderIndividualsina
PopulationandthePlant’sEyeView),nevertheless,thewordcompetitioncreepsintothetitlesofthreeofhispapers(Harper
1961,citedunderBackgroundDevelopment:Oxford,DepartmentofAgriculture;SchmidandHarper1985,citedunder
Competition;FrancoandHarper1988).Interestingly,allofthesephobiawordsareusedinhislandmarkADarwinianApproachto
PlantEcology(Harper1967,citedunderBackgroundDevelopment:UniversityCollegeofNorthWales(UCNW),Bangorand
EvolutionaryEcology),althoughcompetitionisusedonlyonceanditisinquotations.Whenchallengedonhisuseofthesewords
inearlypapers,Harperresponded:“AmInotallowedtochangemymind?”(questionanddiscussionperiod,RoyalSociety

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Symposium,1985).
Franco,Miguel,andJohnL.Harper.1988.Competitionandtheformationofspatialpatterninspacinggradients:An
exampleusingKochiascoparia.JournalofEcology76:959–974.
DespiteHarper’sdistainforhowthewordcompetitionwasusedbyecologists,thewordmanagedtocreepintothetitleofthis
paper.
CompleteBibliographyofthePublishedWorksofJohnL.Harper
ThesecitationsrepresentthecompleteworksofwhichHarperisanauthor.Mostofthecoauthoredpapersthathavebeen
annotatedabovehavebeencitedmorethan130times(WebofKnowledgeorGoogle).Harperdidnotkeeparecordofpapersfor
whichhewasnotacoauthor,eventhoughnumerouspaperswerepublishedbyhisstudentsandvisitorswhileinhislab.Afewof
themoresignificantofthesepublicationsareincludedasannotationsthroughoutthis“CompleteBibliography”butcompilationofa
completelisthasnotbeenattempted.
I.Thesis
Harper,JohnL.1950.Aninvestigationoftheinteractionofsoilmicroorganismswithspecialreferencetothestudyof
thebacterialpopulationsofplantrootsystems.PhDdiss.,MagdalenCollege,UniversityofOxford.
Harper’sD.Phil.workwasneverpublished,buttheideasandworkinPartVofthethesis“Astudyoftherhizosphereofsome
bananavarieties”wereintegratedintoHarper1950aandHarper1950b(bothcitedunderPapers,BookChapters,andConference
Proceedings).Abouthisthesis,Harperwrote,“WhenIcametowriteupmyD.Phil.thesis....technicalproblemsformedhalfthe
thesis.IwroteapapertoNatureaboutthemwhichwasacceptedbutIwithdrewitwhenIdiscoveredyetanothertechnicalproblem
aboutsampling.”(J.L.Harper,unpublishedmemoirs;providedbyClaire,hisdaughter).
II.Papers,BookChapters,andConferenceProceedings
Harper,JohnL.1950a.StudiesintheresistanceofcertainvarietiesofbananatoPanamadisease,I:Internalfactorsforresistance
andantibiotics.PlantandSoil2:374–382.FindThisResource
Harper,JohnL.1950b.StudiesintheresistanceofcertainvarietiesofbananatoPanamadisease,II:Therhizosphere.Plantand
Soil2:383–394.FindThisResource
Osborn,E.M.,andJohnL.Harper.1951.AntibioticproductionbygrowingplantsofLeptosynemaritime.Nature167:685–686.Find
ThisResource
Harper,JohnL.,andGeoffR.Sagar.1953.Someaspectsoftheecologyofbuttercupsinpermanentgrasslands.
ProceedingsoftheBritishWeedControlConference1:256–263.
CitedinBackgroundDevelopment:Oxford,DepartmentofAgriculture.
Harper,JohnL.1954a.Influenceoftemperatureandsoilwatercontentontheseedlingblightofmaize.Nature173:391–393.Find

5/14/2015 JohnL.HarperEcologyOxfordBibliographies
http://www.oxfordbibliographies.com/view/document/obo9780199830060/obo97801998300600135.xml?rskey=k3uMKq&result=62&print 26/40
ThisResource
Harper,JohnL.1954b.SomerelationshipsbetweenthesoilwatertableandthecomparativeecologyofRanunculusbulbosus,R.
repensandR.acris.InHuitièmecongrèsinternationaldebotanique,Paris.EditedbyInternationalBotanicalCongress,207–208.
Paris:InternationalAssociationofPlantTaxonomy.FindThisResource
Harper,JohnL.1955a.Theinfluenceoftheenvironmentonseedandseedlingmortality,VI:Theeffectsoftheinteractionofsoil
moisturecontentandtemperatureonthemortalityofmaizegrains.AnnalsofAppliedBiology43:696–708.FindThisResource
Harper,JohnL.1955b.Problemsinvolvedintheextensionofmaizecultivationintonortherntemperateregions.WorldCrops
7:93:96.FindThisResource
Harper,JohnL.,andPhyllisA.Landragin.1955.Theinfluenceoftheenvironmentonseedandseedlingmortality,IV:Soil
temperatureandmaizegrainmortalitywithspecialreferencetothecoldtestprocedure.PlantandSoil6:360–372.FindThis
Resource
Harper,JohnL.,PhyllisA.Landragin,andJerzyW.Ludwig.1955a.Theinfluenceofenvironmentonseedandseedling
mortality,I:Theinfluenceoftimeofplantingonthegerminationofmaize.NewPhytologist54:107–118.
Thenumberingofthisseries“Theinfluenceoftheenvironmentonseedandseedlingmortality”isnotinsequence:Nos.I,II,IV,
andVIwerepublishedin1955,Vin1956,IIIin1957,andVIIandVIIIin1958.Inaddition,themaintitleoftheseriesisnot
consistent.Nos.I,II,andIIIbegin“Theinfluenceofenvironmenton...”,nos.IV,VI,VII,andVIIbegin“Theinfluenceofthe
environment...”andinno.V“Theinfluenceoftheenvironmenton...”hasbeenreplacedby“Studiesin...”;onlyinnos.IVand
VIIisseedmortalityhyphenated.CitedunderBackgroundDevelopment:Oxford,DepartmentofAgriculture.
Harper,JohnL.,PhyllisA.Landragin,andJerzyW.Ludwig.1955b.Theinfluenceofenvironmentonseedandseedlingmortality,
II:Thepathogenicpotentialofthesoil.NewPhytologist54:119–131.FindThisResource
Acheson,R.Morrin,JohnL.Harper,andIanH.McNaughton.1956.Distributionofanthocyaninpigmentsinpoppies.Nature
178:1283–1284.FindThisResource
Harper,JohnL.1956a.Studiesinseedandseedlingmortality,V:Directandindirecteffectsoflowtemperaturesonthe
mortalityofmaize.NewPhytologist55:35–44.
Eventhoughthistitleisdifferentfromtheothersintheseries,thisisthecorrecttitle.
Harper,JohnL.1956b.Theevolutionofweedsinrelationtoresistancetoherbicides.InProceedingsoftheThirdBritishWeed
ControlConference,1956,NorbreckHydro,Blackpool,England,November6th,7th,and8th,1956.EditedbyBritishWeed
ControlCouncil,179–188.London:BritishWeedControlCouncil.FindThisResource
Harper,JohnL.1957a.Theecologicalsignificanceofdormancyanditsimportanceinweedcontrol.InProceedingsofthe
IVthInternationalCongressofCropProtection,Hamburg.EditedbyJohannesKrause,415–420.Brunswick,Germany:
InternationalCongressofCropProtection.
CitedunderBackgroundDevelopment:Oxford,DepartmentofAgricultureandGermination.
Harper,JohnL.1957b.BiologicalfloraoftheBritishIsles.RanunculusacrisL.,R.repensL.andR.bulbosusL.JournalofEcology
45:289–342.FindThisResource
Harper,JohnL.,andW.A.Wood.1957.BiologicalfloraoftheBritishIsles.SeneciojacobaeaL.JournalofEcology45:617–
637.FindThisResource

5/14/2015 JohnL.HarperEcologyOxfordBibliographies
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Ludwig,JerzyW.,ErnestS.Bunting,andJohnL.Harper.1957.Theinfluenceofenvironmentonseedandseedlingmortality,III:
Theinfluenceofaspectonmaizegermination.JournalofEcology45:205–224.FindThisResource
Harper,JohnL.1958a.Ecologicalaspectsofweedcontrol.OutlookonAgriculture1:197–205.FindThisResource
Harper,JohnL.1958b.Famousplants,8:Thebuttercup.InNewbiology.Vol.26.EditedbyM.L.Johnson,M.Abercrombie,and
G.E.Fogg,30–46.Harmondsworth,UK:Penguin.FindThisResource
Harper,JohnL.1958c.Theecologyofragwort(Seneciojacobaea)withspecialreferencetocontrol.HerbageAbstracts28:151–
157.FindThisResource
Ludwig,JerzyW.,andJohnL.Harper.1958.Theinfluenceoftheenvironmentonseedandseedlingmortality,VII:Depthof
sowingofmaize.PlantandSoil10:37–48.FindThisResource
Ludwig,JerzyW.,andJohnL.Harper.1958.Theinfluenceofenvironmentonseedandseedlingmortality,VIII:Theinfluenceof
soilcolour.JournalofEcology46:381–389.FindThisResource
Harper,JohnL.,andA.PatriciaChancellor.1959.Thecomparativebiologyofcloselyrelatedspecieslivinginthesame
area,IV:Rumex:interferencebetweenindividualsinpopulationsofoneandtwospecies.JournalofEcology47:679–695.
CitedunderCompetition.
Harper,JohnL.1960.Factorscontrollingplantnumbers.InTheBiologyofWeeds.ByJohnL.Harper,119–132.
SymposiumoftheBritishEcologicalSociety1.Oxford:BlackwellScientificPublishing.
CitedunderBackgroundDevelopment:Oxford,DepartmentofAgriculture.
Harper,JohnL.,andIanH.McNaughton.1960.TheinheritanceofdormancyininterandintraspecifichybridsofPapaver.
Heredity15:315–320.FindThisResource
McNaughton,IanH.,andJohnL.Harper.1960.Thecomparativebiologyofcloselyrelatedspecieslivinginthesame
area,I:ExternalbreedingbarriersbetweenPapaverspecies.NewPhytologist58:15–26.
Thenumberingofthepapersintheseries“Thecomparativebiologyofcloselyrelatedspecieslivinginthesamearea”isnotin
sequence.NoIVwasthefirsttobepublishedin1959;noI,II,andIIIin1960,noVandVIIin1962,noVIin1963,andnoIXwas
publishedin1967.NoVI(HarperandClatworthy1963)hasanabbreviatedgeneraltitle.ItappearsthatnoVIIIisprobablyHarper,
etal.1961,althoughthispaperisnotnumberedandhasamodifiedtitle:“Theevolutionandecologyofcloselyrelatedspecies
livinginthesamearea.”CitedunderOxford,DepartmentofAgriculture.
McNaughton,IanH.,andJohnL.Harper.1960a.Thecomparativebiologyofcloselyrelatedspecieslivinginthesamearea,II:
AberrantmorphologyandaviruslikesyndromeinhybridsbetweenPapaverrhoeasL.andP.dubiumL.NewPhytologist59:27–
41.FindThisResource
McNaughton,IanH.,andJohnL.Harper.1960b.Thecomparativebiologyofcloselyrelatedspecieslivinginthesamearea,III:
ThenatureofbarriersisolatingsympatricpopulationsofPapaverdubiumandP.lecoquii.NewPhytologist59:129–137.FindThis
Resource
Sagar,GeoffR.,andJohnL.Harper.1960.Factorsaffectingthegerminationandearlyestablishmentofplantains
(Plantagolanceolata,P.mediaandP.major).TheBiologyofWeeds.BritishEcologicalSocietySymposium1:236–245.
CitedunderGermination.

5/14/2015 JohnL.HarperEcologyOxfordBibliographies
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Harper,JohnL.1961.Approachestothestudyofplantcompetition.InMechanismsinbiologicalcompetition.Editedby
theSocietyforExperimentalBiology,1–39.SymposiaoftheSocietyforExperimentalBiology15.NewYork:Academic
Press.
CitedunderBackgroundDevelopment:Oxford,DepartmentofAgricultureandCompetition.
Harper,JohnL.,JohnN.Clatworthy,IanH.McNaughton,andGeoffR.Sagar.1961.Theevolutionandecologyofclosely
relatedspecieslivinginsamearea.Evolution15:209–227.
Thispaperiseitherthefirst(butunnumbered)paperintheseries“Thecomparativebiologyofcloselyrelatedspecieslivinginthe
samearea”eventhoughitisnotnumberedandhasamodifiedtitle;ifthisiscorrect,thenthereisnonoVIIIintheseries.Second,
itisperhapsthemissingno.VIIIintheseries.Giventheearlyhistoryofthisseriesthefirstoptionismostlikelycorrect.Cited
underBackgroundDevelopment:Oxford,DepartmentofAgriculture.
Harper,JohnL.,andDanicaGajic.1961.Experimentalstudiesonthemortalityandplasticityofaweed.WeedResearch1:91–
104.FindThisResource
Sagar,GeoffR.,andJohnL.Harper.1961.ControlledinterferencewithnaturalpopulationsofPlantagolanceolata,P.
majorandP.minor.WeedResearch1:163–176.
CitedunderCompetition.
Acheson,R.Morrin,C.L.Jenkins,JohnL.Harper,andIanH.McNaughton.1962.FloralpigmentsinPapaverandtheir
significanceinthesystematicsofthegenus.NewPhytologist61:256–260.FindThisResource
Cavers,PaulB.,andJohnL.Harper.1962.TherelativeperformanceofRumexcrispusandRumexobtusifoliusatthreedensities
inpureandmixedstands.InResearchReport:ProceedingsoftheSixthBritishWeedControlConference,Brighton,England,
November6th,7th,and8th,1962.EditedbyBritishWeedControlCouncil,453–462.London:BritishWeedControlCouncil.Find
ThisResource
Clatworthy,JohnN.,andJohnL.Harper.1962.Thecomparativebiologyofcloselyrelatedspecieslivinginthesame
area,V:InterandintraspecificinterferencewithinculturesofLemnaspp.andSalvinianatans.JournalofExperimental
Botany13:307–324.
CitedunderCompetition.
Harper,JohnL.,andIanH.McNaughton.1962a.Thecomparativebiologyofcloselyrelatedspecieslivinginthesame
area,VII:InterferencebetweenindividualsinpureandmixedpopulationsofPapaverspecies.NewPhytologist61:175–
188.
CitedunderBackgroundDevelopment:Oxford,DepartmentofAgriculture.
Harper,JohnL.,andIanH.McNaughton.1962b.Interferenceinmixedpoppypopulations.AnnalsofAppliedBiology50:352.Find
ThisResource
Harper,JohnL.1963.Thebiologicalroleofsoilwater:Introduction.InSoilMoisture.Vol.4.EditedbyD.F.Ball,52–54.
Aberystwyth,UK:WelshSoilsDiscussionGroup.FindThisResource

5/14/2015 JohnL.HarperEcologyOxfordBibliographies
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Harper,JohnL.,andJohnN.Clatworthy.1963.Thecomparativebiologyofcloselyrelatedspecies,VI:Analysisofgrowth
ofTrifoliumrepensandT.fragiferuminpureandmixedpopulations.JournalofExperimentalBotany14:172–190.
Thegeneraltitleofthispaperdiffersfromtheothersintheseries.
Cavers,PaulB.,andJohnL.Harper.1964.BiologicalfloraoftheBritishIsles:No.98:RumexobtusifoliusL.andR.crispusL.
JournalofEcology52:737–766.FindThisResource
Harper,JohnL.1964a.Theindividualinthepopulation.JournalofAnimalEcology33:149–158.
ThispaperisoftenincorrectlycitedasJournalofEcologyvol.52ratherthanJournalofAnimalEcology.CitedunderBackground
Development:UniversityCollegeofNorthWales(UCNW),BangorandIndividualsinaPopulationandthePlant’sEyeView.
Harper,JohnL.1964b.Thenatureandconsequenceofinterferenceamongstplants.InGeneticstoday:Proceedingsof
theXIthInternationalCongressofGenetics,TheHague,theNetherlands,September1963.Vol.2.EditedbyS.J.Geerts,
465–482.Oxford:Pergamon.
CitedunderBackgroundDevelopment:UniversityCollegeofNorthWales(UCNW),BangorandCompetition.
McNaughton,IanH.,andJohnL.Harper.1964.BiologicalfloraoftheBritishIsles:No.99.PapaverL.JournalofEcology52:767–
793.FindThisResource
Sagar,GeoffR.,andJohnL.Harper.1964.BiologicalfloraoftheBritishIsles:No.95.PlantagomajorL,P.mediaL.andP.
lanceolataL.JournalofEcology52:189–221.FindThisResource
Govier,RobinN.,andJohnL.Harper.1965.Angiospermoushemiparasites.Nature205:722–723.FindThisResource
Harper,JohnL.1965.Establishment,aggression,andcohabitationinweedyspecies.InThegeneticsofcolonizing
species.EditedbyHerbertG.BakerandG.LedyardStebbins,243–263.NewYork:AcademicPress.
CitedunderBackgroundDevelopment:UniversityCollegeofNorthWales(UCNW),Bangor.
Harper,JohnL.,J.TrevorWilliams,andGeoffR.Sagar.1965.Thebehaviourofseedsinsoil,I:Theheterogeneityofsoil
surfacesanditsroleindeterminingtheestablishmentofplantsfromseed.JournalofEcology53:273–286.
CitedunderGermination.
Williams,J.Trevor,andJohnL.Harper.1965.Seedpolymorphismandgermination,I:Theinfluenceofnitratesandlow
temperaturesonthegerminationofChenopodiumalbum.WeedResearch5:141–150.
CitedunderGermination.NoIIinthisseriesisJ.TrevorWilliams(1971)“Seedpolymorphismandgermination,II:Theroleof
hybridizationinthegerminationpolymorphismofRumexcrispusandR.obtusifolius,”WeedResearch11:12–21.
Cavers,PaulB.,andJohnL.Harper.1966.GerminationpolymorphisminRumexcrispusandRumexobtusifolius.Journal
ofEcology54:367–382.
CitedunderGermination.

5/14/2015 JohnL.HarperEcologyOxfordBibliographies
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Harper,JohnL.1966.ThereproductivebiologyoftheBritishpoppies.InReproductivebiologyandtaxonomyofvascularplants.
EditedbyJ.G.Hawkes,26–39.London:BotanicalSocietyoftheBritishIsles.FindThisResource
Harper,JohnL.,andRichardA.Benton.1966.Thebehaviourofseedsinsoil,II:Germinationofseedsonsurfaceofa
watersupplyingsubstrate.JournalofEcology54:151–166.
CitedunderGermination.NoIIIinthisseriesisJohnC.Sheldon(1974),“Thebehaviourofseedsinsoil,III:Theinfluenceofseed
morphologyandthebehaviourofseedlingsontheestablishmentofplantsfromsurfacelyingseeds”JournalofEcology62:47–66.
Cavers,PaulB.,andJohnL.Harper.1967a.Thecomparativebiologyofcloselyrelatedspecieslivinginthesamearea,IX:
Rumex:Thenatureofadaptationofaseashorehabitat.JournalofEcology55:73–82.FindThisResource
Cavers,PaulB.,andJohnL.Harper.1967b.Studiesinthedynamicsofplantpopulations,I:Thefateofseedand
transplantsintroducedintovarioushabitats.JournalofEcology55:59–71.
ThereisnonumberIVintheseries“Studiesinthedynamicsofplantpopulations,”butthereisanumberI,II,II,andV.Citedunder
PlantPopulationDynamics.
Harper,JohnL.1967a.ADarwinianapproachtoplantecology:Presidentialaddress:BritishEcologicalSociety.Journal
ofEcology55:247–270.
ThispaperwasoneoffourpapersfromHarper’slablistedas“oneofthetop100mostinfluentialpaperspublishedbytheBritish
EcologicalSociety(1913–2012)”aspartoftheBEScentenarycelebrations.AlsoavailableinJournalofAppliedEcology4(1967):
267–290,andJournalofAnimalEcology36(1967):495–518.ThepaperisalsoincludedinLeslieA.RealandJamesH.Brown,
FoundationsofEcology:ClassicPaperswithCommentaries(Chicago:UniversityofChicagoPress,1991).Citedunder
BackgroundDevelopment:UniversityCollegeofNorthWales(UCNW),Bangor,EvolutionaryEcology,andClarityandPrecision.
Harper,JohnL.1967b.Theteachingofexperimentalecology.InTheteachingofecology.EditedbyJoyceM.Lambert,135–146.
SymposiumoftheBritishEcologicalSociety7.Oxford:Blackwell.FindThisResource
Harper,JohnL.,andMohammedObeid.1967.Influenceofseedsizeanddepthofsowingonestablishmentandgrowthof
varietiesoffiberandoilseedflax.CropScience7:527–532.FindThisResource
Litav,Michael,andJohnL.Harper.1967.Amethodforstudyingspatialrelationshipsbetweenrootsystemsoftwoneighbouring
plants.PlantandSoil26:389–392.FindThisResource
Obeid,Mohammed,DavidMachin,andJohnL.Harper.1967.Influenceofdensityonplanttoplantvariationinfiberflax
LinumusitatissimumL.CropScience7:471–473.
CitedunderCompetition.
Harper,JohnL.1968.Theregulationofnumbersandmassinplantpopulations.InPopulationbiologyandevolution.
EditedbyRichardC.Lewontin,139–158.NewYork:SyracuseUniv.Press.
CitedunderBackgroundDevelopment:UniversityCollegeofNorthWales(UCNW),BangorandRegulation.
Putwain,PhilipD.,DavidMachin,andJohnL.Harper.1968.Studiesinthedynamicsofplantpopulations,II:Componentsand

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regulationofanaturalpopulationofRumexacetosellaL.JournalofEcology56:421–431.FindThisResource
Harper,JohnL.1969.Theroleofpredationinvegetationaldiversity.InDiversityandstabilityinecologicalsystems:
ReportofasymposiumheldMay26–28,1969.EditedbyG.M.WoodwellandH.H.Smith,48–62.BrookhavenSymposiain
Biology22.Upton,NY:BrookhavenNationalLaboratory.
CitedunderBackgroundDevelopment:UniversityCollegeofNorthWales(UCNW),BangorandDarwinianandWallacian
Perspectives.
Hatto,Jane,andJohnL.Harper.1969.ThecontrolofslugsandsnailsinBritishcroppingsystems,especiallygrassland.
ProjectNo.115A.InternationalCopperResearchAssociation.
AreportoftheresultsofaninvestigationsupportedbyaGrantinAidfromtheInternationalCopperResearchAssociationInc.
carriedoutattheSchoolofPlantBiology,UniversityCollegeofNorthWales,Bangorfrom1966–1969.Thisreporthasbeencited
manytimes,oftenwiththeauthorshipreversed,andoftendated1968.Thereasonforsomuchconfusioninitscitationisthatthe
reportwasnotpublished.ThereportisconfidentialandisthepropertyoftheInternationalCopperResearchAssociation.
Informationinthereport“maynotbepublishedexceptwiththewrittenauthorizationoftheInternationalCopperResearch
Association.”
Ellern,SigmundJ.,JohnL.Harper,andGeoffR.Sagar.1970.ComparativestudyofdistributionofrootsofAvenafatuaandA.
strigosainmixedstandsusinga14Clabellingtechnique.JournalofEcology58:865–868.FindThisResource
Harper,JohnL.1970.Grazing,fertilizersandpesticidesinthemanagementofgrasslands.InThescientificmanagementofanimal
andplantcommunitiesforconservation:The11thsymposiumoftheBritishEcologicalSociety,UniversityofEastAnglia,Norwich,
7–9July1970.EditedbyE.DuffeyandAlexS.Watt,15–31.Oxford:Blackwell.FindThisResource
Harper,JohnL.,PeterH.Lovell,andKeithG.Moore.1970.Theshapesandsizesofseeds.AnnualReviewofEcologyand
Systematics1:327–356.
CitedunderGerminationandReproductiveStrategies.
Ogden,John,andJohnL.Harper.1970.Thereproductivestrategyofhigherplants,I:Theconceptofstrategywith
specialreferencetoSeneciovulgarisL.JournalofEcology58:681–698.
CitedunderReproductiveStrategies.No.IIinthisseriesisJohnOgden,“TheReproductiveStrategyofHigherPlants,II:The
ReproductiveStrategyofTussilagofarfaraL.,”JournalofEcology62(1974):291–324.
Putwain,PhilipD.,andJohnL.Harper.1970.Studiesinthedynamicsofplantpopulations,III:Influenceofassociatedspecieson
populationsofRumexacetosaL.andR.acetosellaL.ingrassland.JournalofEcology58:251–264.FindThisResource
White,James,andJohnL.Harper.1970.Correlatedchangesinplantsizeandnumberinplantpopulations.Journalof
Ecology58:467–485.
CitedunderPlantPopulationDynamics.
Harper,JohnL.,andJamesWhite.1971.Thedynamicsofplantpopulations.InDynamicsofpopulations:Proceedingsof
theAdvancedStudyInstituteonDynamicsofNumbersinPopulations,Oosterbeek,theNetherlands,7–18September

5/14/2015 JohnL.HarperEcologyOxfordBibliographies
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1970.EditedbyJ.denBoerandG.R.Gradwell,41–63.Wageningen,TheNetherlands:CentreforAgriculturalPublishing
andDocumentation.
CitedunderPlantPopulationDynamicsandGermination.
Harper,JohnL.1972.Projectsandtheirassessmentindegreeexaminations.JournalofBiologicalEducation6:318–321.FindThis
Resource
Putwain,PhilipD.,andJohnL.Harper.1972.Studiesinthedynamicsofplantpopulations,V:Mechanismsgoverningsex
ratioinRumexacetosaandR.acetosella.JournalofEcology60:113–129.
CitedunderPlantPopulationDynamics.
Ross,MaxA.,andJohnL.Harper.1972.Occupationofbiologicalspaceduringseedlingestablishment.Journalof
Ecology60:77–88.
CitedunderIndividualsinaPopulationandthePlant’sEyeView.
Haizel,KwesiA.,andJohnL.Harper.1973.Theeffectsofdensityandtimingofremovaloninterferencebetweenbarley,white
mustardandwildoats.JournalofAppliedEcology10:23–31.FindThisResource
Sarukhán,José,andJohnL.Harper.1973.Studiesonplantdemography:RanunculusrepensL.,R.bulbosusL.andR.
acrisL.,I:Populationfluxandsurvivorship.JournalofEcology61:675–716.
ThispaperisoneoffourpapersfromHarper’slablistedas“oneofthetop100mostinfluentialpaperspublishedbytheBritish
EcologicalSociety(19132012)”aspartoftheBEScentenarycelebrations.Availableonline.CitedunderDemography.NoIIandIII
inthisseriesareJoséSarukhan(1974)“Studiesonplantdemography:RanunculusrepensL.,R.bulbosusL.andR.acrisL.,II:
Reproductivestrategiesandseedpopulationdynamics,”JournalofEcology62:151–177,andJoséSarukhanandMadhavGadgil
(1974)“Studiesonplantdemography:RanunculusrepensL.,R.bulbosusL.andR.acrisL.,III:Amathematicalmodel
Incorporatingmultiplemodesofreproduction,”JournalofEcology62:921–936.
Trenbath,BrianR.,andJohnL.Harper.1973.NeighboureffectsinthegenusAvena,I:Comparisonofcropspecies.
JournalofAppliedEcology10:379–400.
Nos.IIandIIIinthisseriesareBrianR.Trenbath(1974)“NeighboureffectsinthegenusAvena,II:Comparisonofweedspecies,”
JournalofAppliedEcology11:111–125,andBrianR.Trenbath(1975)“NeighboureffectsinthegenusAvena,III:Adiallel
approach,”JournalofAppliedEcology12:189–200.Availableonlineforpurchase.
Tripathi,RadheyS.,andJohnL.Harper.1973.ComparativebiologyofAgropyronrepens(L)BeauvandAgropyron
caninum(L)Beauv,I:Growthofmixedpopulationsestablishedfromtillersandfromseeds.JournalofEcology61:353–
368.
Thereappearstobenofurtherpapersinthisplannedseries.
Harper,JohnL.1974.Agriculturalecosystems.AgroEcosystems1:1–6.FindThisResource
Harper,JohnL.1974.Centenaryinpopulationbiology.Nature252:526–527.FindThisResource

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Harper,JohnL.1974.Soilsterilizationanddisinfection:Theperturbationofecosystems.AgroEcosystems1:105–106.FindThis
Resource
Harper,JohnL.,andJamesWhite.1974.Thedemographyofplants.AnnualReviewofEcologyandSystematics5:419–
463.
CitedunderEcologicalTheoryandDemographicApproachtoPlantForm(Plasticity).
Kays,Stanley,andJohnL.Harper.1974.Theregulationofplantandtillerdensityinagrasssward.JournalofEcology
62:97–105.
CitedunderRegulation.
Bazzaz,FakhriA.,andJohnL.Harper.1976.RelationshipbetweenplantweightandnumbersinmixedpopulationsofSinapsis
alba(L.)RabenhandLepidiumsativumL.JournalofAppliedEcology13:211–216.FindThisResource
Cahn,MartinG.,andJohnL.Harper.1976.ThebiologyofleafmarkpolymorphisminTrifoliumrepensL.I.Distributionof
phenotypesatalocalscale.Heredity37:309–325.
CitedunderExperimentalEcology.
Cahn,MartinG.,andJohnL.Harper.1976.ThebiologyofleafmarkpolymorphisminTrifoliumrepensL.II:Evidenceforselection
ofleafmarksbyrumenfistulatedsheep.Heredity37:327–333.FindThisResource
Bazzaz,FakhriA.,andJohnL.Harper.1977.DemographicanalysisofgrowthofLinumusitatissimum.NewPhytologist
78:193–208.
CitedunderDemographicApproachtoPlantForm(Plasticity).
Harper,JohnL.1977.Thecontributionsofterrestrialplantstudiestothedevelopmentofthetheoryofecology.Special
PublicationoftheAcademyofNaturalSciencesPhiladelphia12:139–157.
CitedunderIndividualsinaPopulationandthePlant’sEyeViewandEcologicalTheory.
Harper,JohnL.1977.Plantrelationsinpastures.InPlantrelationsinpastures.EditedbyJ.R.Wilson,3–14.Melbourne:
CommonwealthScientificandIndustrialOrganization.
CitedunderEcologicalTheory.
Mack,RichardN.,andJohnL.Harper.1977.Interferenceinduneannuals:Spatialpatternandneighbourhoodeffects.
JournalofEcology65:345–363.
ThispaperwasoneoffourpapersfromHarper’slablistedas“oneofthetop100mostinfluentialpaperspublishedbytheBritish
EcologicalSociety(1913–2012)”aspartoftheBEScentenarycelebrations.Availableonline.CitedunderIndividualsina
PopulationandthePlant’sEyeViewandCompetition.

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Harper,JohnL.1978.Thedemographyofplantswithclonalgrowth.InStructureandfunctioningofplantpopulations.
EditedbyA.H.J.FreysenandJ.W.Woldendorp,27–48.Amsterdam:NorthHolland.
CitedunderDemography.
Watkinson,AndrewR.,andJohnL.Harper.1978.Thedemographyofasandduneannual:Vulpiafasciculata,I:The
naturalregulationofpopulations.JournalofEcology66:15–33.
CitedunderRegulationandDemography.NoIIandIIIinthisseriesareAndrewR.Watkinson(1978)“Thedemographyofasand
duneannual:Vulpiafasciculata,II:Thedynamicsofseedpopulations,”JournalofEcology66:35–44,andAndrewR.Watkinson
(1978)“Thedemographyofasandduneannual:Vulpiafasciculata,III:Thedispersalofseeds,”JournalofEcology66:483–498.
Bazzaz,FakhriA.,RogerW.Carlson,andJohnL.Harper.1979.Contributiontoreproductiveeffortbyphotosynthesisof
flowersandfruits.Nature279:554–555.
CitedunderReproductiveStrategies.
Harper,JohnL.,andAdrianD.Bell.1979.Thepopulationdynamicsofgrowthforminorganismswithmodular
construction.InPopulationdynamics:The20thsymposiumoftheBritishEcologicalSociety.EditedbyR.M.Anderson,
D.Turner,andL.R.Taylor,29–52.Oxford:Blackwell.
CitedunderDemographicApproachtoPlantForm(Plasticity).
Huiskes,H.L.,andJohnL.Harper.1979.ThedemographyofleavesandtillersofAmmophilaarenariainadunesere.Oecologia
Plantarum14:435–446.FindThisResource
Noble,JamesC.,AdrianD.Bell,andJohnL.Harper.1979.Thepopulationbiologyofplantswithclonalgrowth,I:
MorphologyandstructuraldemographyofCarexarenaria.JournalofEcology67:983–1008.
CitedunderDemography.Nos.IIandIIIinthisseriesareJamesC.NobleandChrisMarshall(1983)“Thepopulationbiologyof
plantswithclonalgrowth,II:ThenutrientstrategyandmodularphysiologyofCarexarenaria,”JournalofEcology71:865–877,
andNevilleR.BartlettandJamesC.Noble(1985)“ThePopulationBiologyofPlantswithClonalGrowth,III:AnalysisofTiller
MortalityinCarexArenaria,”JournalofEcology73:1–10.
Onyekwelu,SteveS.,andJohnL.Harper.1979.Sexratioandnichedifferentiationinspinach(SpinaciaoleraceaL.).Nature
282:609–611.FindThisResource
Turkington,Roy,andJohnL.Harper.1979.ThegrowthdistributionandneighbourrelationshipsofTrifoliumrepensina
permanentpasture,I:Ordinationpatternandcontact.JournalofEcology67:201–218.
CitedunderIndividualsinaPopulationandthePlant’sEyeViewandExperimentalEcology.
Turkington,Roy,andJohnL.Harper.1979.Thegrowth,distributionandneighbourrelationshipsofTrifoliumrepensina
permanentpasture,II:Interandintraspecificcontact.JournalofEcology67:219–230.FindThisResource
Turkington,Roy,MartinA.Cahn,AlexVardy,andJohnL.Harper.1979.Thegrowth,distributionandneighbourrelationshipsof
Trifoliumrepensinapermanentpasture,III:EstablishmentandgrowthofTrifoliumrepensinnaturalandperturbedsites.Journal

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ofEcology67:231–243.FindThisResource
Turkington,Roy,andJohnL.Harper.1979.Thegrowth,distributionandneighbourrelationshipsofTrifoliumrepensina
permanentpasture,IV:Finescalebioticdifferentiation.JournalofEcology67:245–254.
ThispaperwasoneoffourpapersfromHarper’slablistedas“oneofthetop100mostinfluentialpaperspublishedbytheBritish
EcologicalSociety(1913–2012)”aspartoftheBEScentenarycelebrations.NoVandVIinthisseriesareRoyTurkington(1989)
“Thegrowth,distributionandneighbourrelationshipsofTrifoliumrepensinapermanentpasture,V:Thecoevolutionof
competitors,”JournalofEcology77:717–733,andRoyTurkington(1989)“Thegrowth,distributionandneighbourrelationshipsof
Trifoliumrepensinapermanentpasture,VI:Conditioningeffectsbyneighbours,”JournalofEcology77:734–746.Citedunder
DarwinianandWallacianPerspectives.
Burdon,JeremyJ.,andJohnL.Harper.1980.Relativegrowthratesofindividualmembersofaplantpopulation.Journal
ofEcology68:953–957.
Acompaniontothis,withoutHarperasacoauthor,isJeremyJ.Burdon,“IntraspecificDiversityinaNaturalPopulationof
Trifoliumrepens,”JournalofEcology68(1980):717–735.
Dirzo,Rodolfo,andJohnL.Harper.1980.Experimentalstudiesonslugplantinteractions,II:Theeffectofgrazingby
slugsonhighdensitymonoculturesofCapsellabursapastorisandPoaannua.JournalofEcology68:999–1011.
No.IinthisseriesoffourpapersisasingleauthoredpaperwithoutHarperasacoauthor.RodolfoDirzo,“ExperimentalStudieson
SlugPlantInteractions,I:TheAcceptabilityofThirtyPlantSpeciestotheSlugAgriolomaxcaruanae,”JournalofEcology68
(1980):981–998.
Harper,JohnL.1980.Plantdemographyandecologicaltheory.Oikos35:244–253.
CitedunderEcologicalTheory.
LovettDoust,Jon,andJohnL.Harper.1980.Theresourcecostsofgenderandmaternalsupportinanandromonoecious
UmbelliferSmyrniumolusatrum.NewPhytologist85:251–264.FindThisResource
Vernet,Phillipe,andJohnL.Harper.1980.Thecostsofsexinseaweeds.BiologicalJournaloftheLinneanSociety13:129–
138.FindThisResource
Harper,JohnL.1981.Theconceptofpopulationinmodularorganisms.InTheoreticalecology.2ded.EditedbyRobert
M.May,53–77.Oxford:Blackwell.
CitedunderDemographicApproachtoPlantForm(Plasticity).
Harper,JohnL.1981.Themeaningofrarity.InThebiologicalaspectsofrareplantconservation.EditedbyHughSynge,189–
203.NewYork:Wiley.FindThisResource
Dirzo,Rodolfo,andJohnL.Harper.1982a.Experimentalstudiesonslugplantinteractions,III:Differencesinthe
acceptabilityofindividualplantsofTrifoliumrepenstoslugsandsnails.JournalofEcology70:101–117.
CitedunderDarwinianandWallacianPerspectives.

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Dirzo,Rodolfo,andJohnL.Harper.1982b.Experimentalstudiesonslugplantinteractions,IV:Theperformanceof
cyanogenicandacyanogenicmorphsofTrifoliumrepensinthefield.JournalofEcology70:119–138.
CitedunderDarwinianandWallacianPerspectivesandExperimentalEcology.
Harper,JohnL.1982.Afterdescription.InTheplantcommunityasaworkingmechanism.EditedbyEdwardI.Newman,
11–25.SpecialPublicationoftheBritishEcologicalSociety1.Oxford:Blackwell.
CitedunderExperimentalEcology.
Harper,JohnL.1982.Thebiologyofwhiteclover(Trifoliumrepens)inapermanentpasture.InThesecondnationalsymposium
onnitrogenfixation,Helsinki,8th–10thofJune1982.EditedbyH.GyllenbergandEeroHorstia,255–260.Helsinki:Finnish
NationalFundforResearchandDevelopment.FindThisResource
Fowler,Norma,JohnZasada,andJohnL.Harper.1983.GeneticcomponentsofmorphologicalvariationinSalixrepens.New
Phytologist95:121–131.FindThisResource
Harper,JohnL.1983.ADarwinianplantecology.InEvolutionfrommoleculestomen.EditedbyD.Bendall,323–345.
Cambridge,UK:CambridgeUniv.Press.
CitedunderEvolutionaryEcologyandExperimentalEcology.
Mithen,Richard,JohnL.Harper,andJacobWeiner.1984.Growthandmortalityofindividualplantsasafunctionof
availablearea.Oecologia62:57–60.
CitedunderIndividualsinaPopulationandthePlant’sEyeView.
Harper,JohnL.1985.Modules,branches,andthecaptureofresources.InPopulationbiologyandevolutionofclonalorganisms.
EditedbyJ.B.C.Jackson,L.W.Buss,andR.E.Cook,1–33.NewHaven,CT:YaleUniv.Press.FindThisResource
Schmid,Bernhard,andJohnL.Harper.1985.Clonalgrowthingrasslandperennials,I:Densityandpatterndependent
competitionbetweenplantswithdifferentgrowthforms.JournalofEcology73:793–808.
CitedunderCompetition.NoIIandIIIinthisseriesareBernhardSchmid(1985)“Clonalgrowthingrasslandperennials,II:Growth
formandfinescalecolonizingability,”JournalofEcology73:809–818,andBernhardSchmid(1985)“Clonalgrowthingrassland
perennials,III:GeneticvariationandplasticitybetweenandwithinpopulationsofBellisperennisandPrunellavulgaris,”Journalof
Ecology73:819–830.
Turkington,Roy,JohnL.Harper,PietDeJong,andLonnieW.Aarssen.1985.Areanalysisofinterspecificassociationinanold
pasture.JournalofEcology73:123–131.FindThisResource
Harper,JohnL.1986.Biologiapopulacyjnaiewolucjaorganizmowklonalynch:Modulyirozgalezieniaapobieranie
skladikowpokarmowych.WiadomosciEkologiczne32:327–359.
ThePolishtitleistranslatedas“Populationbiologyandevolutionofclonalorganisms:Modulesbranchesandthecaptureof
resources.”

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Harper,JohnL.,BrianR.Rosen,andJamesWhite.1986.Thegrowthandformofmodularorganisms—preface.Philosophical
TransactionsoftheRoyalSocietyofLondon,BiologicalSciences313:3–5.FindThisResource
Harper,JohnL.,andC.(Katie)Sellek.1987.Theeffectsofseveremineralnutrientdeficienciesonthedemographyofleaves.
ProceedingsoftheRoyalSocietyofLondon,BiologicalSciences232:137–157.FindThisResource
Harper,JohnL.,andHilaryL.Wallace.1987.ControloffecunditythroughabortioninEpilobiummontanumL.Oecologia74:31–
38.FindThisResource
Jones,Michelle,andJohnL.Harper.1987.Theinfluenceofneighboursonthegrowthoftrees,I:Thedemographyofbudsin
Betulapendula.ProceedingsoftheRoyalSocietyofLondon,BiologicalSciences232:1–18.FindThisResource
Jones,Michelle,andJohnL.Harper.1987.Theinfluenceofneighboursonthegrowthoftrees,II:Thefateofbudsonlongand
shortshootsinBetulapendula.ProceedingsoftheRoyalSocietyofLondon,BiologicalSciences232:19–33.FindThisResource
SackvilleHamilton,N.Ruaraidh,BernhardSchmid,andJohnL.Harper.1987.Lifehistoryconceptsandthepopulation
biologyofclonalorganisms.ProceedingsoftheRoyalSocietyofLondon,BiologicalSciences232:35–57.
CitedunderDemographicApproachtoPlantForm(Plasticity).
Solangaarachchi,S.Mangalica,andJohnL.Harper.1987.Theeffectofcanopyfilteredlightonthegrowthofwhiteclover
Trifoliumrepens.Oecologia72:372–376.FindThisResource
Franco,Miguel,andJohnL.Harper.1988.Competitionandtheformationofspatialpatterninspacinggradients:An
exampleusingKochiascoparia.JournalofEcology76:959–974.
CitedunderClarityandPrecision.
Thompson,Lindsey,andJohnL.Harper.1988.Theeffectofgrassesonthequalityoftransmittedradiationanditsinfluenceon
thegrowthofwhitecloverTrifoliumrepens.Oecologia75:343–347.FindThisResource
Alliende,M.Catalina,andJohnL.Harper.1989.Demographicstudiesofadioecioustree,I:Colonization,sexandage
structureofapopulationofSalixcinerea.JournalofEcology77:1029–1047.
CitedunderReproductiveStrategies.No.IIinthisseriesisM.CatalinaAlliende,JournalofEcology77(1989):1048–1058.
Harper,JohnL.1989.Canopiesaspopulations.InPlantcanopies:Theirgrowth,formandfunction.EditedbyG.Russell,G.
Marshall,andP.G.Jarvis,105–128.SocietyforExperimentalBiologySeminar31.Cambridge,UK:CambridgeUniv.Press.Find
ThisResource
Harper,JohnL.1989.Plantdemography:AcitationclassiccommentaryonPopulationBiologyofPlantsbyJohnL.
Harper.CurrentContents/Agriculture,BiologyandEnvironmentalSciences5:14.
WhenthiscitationwaspublishedonJanuary30,1989,ThePopulationBiologyofPlantshadbeencitedinmorethan1,660
publications.ByFebruary2015thecountwasover11,000.
Harper,JohnL.1989.Thevalueofaleaf.Oecologia80:53–58.FindThisResource
SackvilleHamilton,N.Ruaraidh,andJohnL.Harper.1989.ThedynamicsofTrifoliumrepensinapermanentpasture,I:

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Thepopulationdynamicsofleavesandnodespershootaxis.ProceedingsoftheRoyalSocietyofLondon,Biological
Sciences237:133–173.
No.IIinthisseriesisN.RuaraidhSackvilleHamilton(1990)“ThedynamicsofTrifoliumrepensinapermanentpasture,II:
Internodelengthandthemovementofshootaxes,”ProceedingsoftheRoyalSocietyofLondon,BiologicalSciences239:359–381.
Solangaarachchi,S.Mangalika,andJohnL.Harper.1989.Thegrowthandasymmetryofneighbouringplantsofwhiteclover
(TrifoliumrepensL.).Oecologia78:208–213.FindThisResource
Boutin,Céline,andJohnL.Harper.1991.AcomparativestudyofthepopulationdynamicsoffivespeciesofVeronicainnatural
habitats.JournalofEcology79:199–221.FindThisResource
Harper,JohnL.,MichelleJones,andN.RuaraidhSackvilleHamilton.1991.Theevolutionofrootsandtheproblemsofanalysing
theirbehaviour.InPlantrootgrowth:Anecologicalperspective.EditedbyD.Atkinson,3–22.SpecialPublicationoftheBritish
EcologicalSociety10.Cambridge,UK:Blackwell.FindThisResource
SackvilleHamilton,N.Ruaraidh,MichelleJones,andJohnL.Harper.1991.Automatedanalysisofrootsinbulksoil.InPlantRoot
Growth:AnEcologicalPerspective.EditedbyD.Atkinson.SpecialPublicationoftheBritishEcologicalSociety10:69–74.
Cambridge,UK:Blackwell.FindThisResource
Harper,JohnL.,andDavidL.Hawksworth.1994.Biodiversity:Measurementandestimation:Preface.PhilosophicalTransactions
oftheRoyalSocietyofLondon,BiologicalSciences345:5–12.FindThisResource
Harper,JohnL.1995.Editorialnote.ProceedingsoftheRoyalSocietyofLondon,BiologicalSciences262:247.FindThis
Resource
Harper,JohnL.,JonathanSilvertown,andMiguelFranco.1996.Plantlifehistories:Ecologicalcorrelatesandphylogenetic
constraints:Preface.PhilosophicalTransactionsoftheRoyalSocietyofLondon,BiologicalSciences351:1227–1231.FindThis
Resource
III.BooksandEditedVolumes
Harper,JohnL.,ed.1960.Thebiologyofweeds.SymposiumoftheBritishEcologicalSociety1.Oxford:Blackwell.FindThis
Resource
Harper,JohnL.1977.Populationbiologyofplants.London:AcademicPress.FindThisResource
Chaloner,WilliamG.,JohnL.Harper,andJohnH.Lawton,eds.1991.Theevolutionaryinteractionofanimalsandplants.
PhilosophicalTransactionsoftheRoyalSocietyofLondon,BiologicalSciences333.London:RoyalSociety.FindThisResource
Silvertown,Jonathan,MiguelFranco,andJohnL.Harper,eds.1997.Plantlifehistories:Ecology,phylogenyandevolution.
Cambridge,UK:CambridgeUniv.Press.FindThisResource
Begon,Michael,ColinR.Townsend,andJohnL.Harper.2006.Ecology:Fromindividualstoecosystems.4thed.Oxford:
BlackwellScience.
FormerlyknownasEcology:Individuals,PopulationandCommunities.Publishedinthreeeditions(1986,1990,and1996).Forthe
1996edition,withMichaelBegonandColinR.Townsend.
Townsend,ColinR.,JohnL.Harper,andMichaelBegon.2008.Essentialsofecology.3ded.Oxford:Blackwell.
Originallypublishedin1999;2nded.2003.

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IV.ReviewsofPopulationBiologyofPlants
Woodell,StanR.J.1977.Bestkindofnaturalhistory.Nature270:545.
CitedunderBooks:PopulationBiologyofPlants.
Bentley,Barbara.1978.Reviews.QuarterlyReviewofBiology58:319.
Availableonline.
Clapham,ArthurR.1978.Reviews:PopulationbiologyofplantsbyJohnL.Harper.NewPhytologist81.1:201–204.
Availableonline.
Jones,EustaceW.1978.Reviews.Forestry51.1:95–97.FindThisResource
Mooney,HaroldA.1978.Plantecology:Mattersofnumbers.Science199:675–676.FindThisResource
Trenbath,BrianR.1978.PopulationbiologyofplantsbyJ.L.Harper.JournalofAppliedEcology15.2:642–644.FindThis
Resource
vanderMeijden,Eddy.1978.PopulationbiologyofplantsbyJohnL.Harper.Vegetatio38.1:61–62.
Availableonline.CitedunderBooks:PopulationBiologyofPlants.
Liddle,MikeJ.1979.PopulationbiologyofplantsbyJohnL.Harper.BiologicalConservation15:82–83.FindThisResource
Solbrig,Otto.1979.PopulationbiologyofplantsbyJ.L.Harper.JournalofEcology67.1:386–388.
CitedunderBooks:PopulationBiologyofPlants.
Harper,JohnL.1989.Plantdemography:AcitationclassiccommentaryonPopulationBiologyofPlantsbyJohnL.
Harper.CurrentContents/Agriculture,BiologyandEnvironmentalSciences5:14.
WhenthiscitationwaspublishedonJanuary30,1989,ThePopulationBiologyofPlantshadbeencitedinmorethan1,660
publications.BySeptember2014thecountwas10,819.CitedunderBiography.
V.BiographicandBibliographic
Hutchings,Mike,DavidGibson,andRichardBardgett.VirtualIssue:InmemoriumJohnL.Harper.JournalofEcology.FindThis
Resource

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Anonymous.1985.ScientificpublicationsofJohnL.Harper,1950–1985.InStudiesofplantdemography:Afestschriftfor
JohnL.Harper.EditedbyJamesWhite,xxvi–xxiii.London:AcademicPress.
CitedunderCollaborationandMentorship.
Sagar,GeoffR.1985.ProfileofJohnL.Harper.InStudiesofplantdemography:AfestschriftforJohnL.Harper.Edited
byJamesWhite,xix–xxv.London:AcademicPress.
CitedunderBiography.
Werner,Patricia.1985.Eminentecologistcitation:AwardedtoJ.L.HarperbytheEcologicalSocietyofAmerica.Bulletin
oftheEcologicalSocietyofAmerica66:20–21.
CitedunderAwardsandService.
Anonymous.1990.TheDarwinmedal:AwardedtoJ.L.HarperbytheRoyalSocietyofLondon.RoyalSocietyNews5:4.
CitedunderAwardsandService.
Anonymous.2000.MarshAwardforecology:AwardedtoJ.L.HarperbytheBritishEcologicalSociety.Bulletinofthe
BritishEcologicalSociety31:15.
CitedunderAwardsandService.
Franco,Miguel,JoséSarukhán,andRodolfoDirzo.2009.ADarwinianplantecologist,JohnLanderHarperCBEFRS,
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Turkington,Roy.2009.Obituary:ProfessorJohnL.HarperFRSCBE,1925–2009.JournalofEcology97:835–837.
CitedunderBiography.Reprinted,BulletinoftheEcologicalSocietyofAmerica91(2010):9–13.
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