DISCUSSION
Levelsofwithin-populationexpectedheterozygosity(HGeneticdiversityandlevelsofclonalityinperipheralpopulationscalculatedofHypopitysmonotropa
.forpopulationswithN≥5(Table3)rangedfromE)0309(CastleCaldwellpopulationCC2,2007)to0.672(StraidkillypopulationS3,2009),withmeanvaluesof0.507Despiteoccurringinsmall,highlyfragmentedpopulationsinand0.492inbothyears.LevelsofHEcalculatedacrossbothNorthernIreland,Hypopitysmonotropaexhibitedrelativelyyearsrangedfrom0.336(CastleCaldwellpopulationCC2)highlevelsofwithin-populationgeneticdiversity.Theto0.672(StraidkillypopulationS3),withameanvalueofobservedmeanclonaldiversity(R)valueof0.804wasvery0.521.Levelsofclonaldiversity(R)rangedfrom0.571highcomparedwiththeaveragevalueforclonalplants(CastleCaldwellpopulationsCC3andCC5)to1.000(Castle(R¼0.17)reportedbyEllstrandandRoose(1987).ThisCaldwellpopulationCC2andElyLodgepopulationsEL3
gurewasalsoattheupperendoftherangeofmorerecentlypublishedvaluesforunderstoreyherbspecies[0.08,
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Page6of8Beatty&Provan—ClonaldiversityinH.monotropa
TABLE3.Levelsofexpectedheterozygosity(HE)andclonaldiversity(R),andinbreedingcoef cient(FIS)bypopulation
HE
RFIS
Population
Year1*Year2 BothPYear1*Year2 BothYear1*Year2 StraidkillyS10.5830.0.0.9650.5800.4970.StraidkillyS20..540.5660.1060.77305820.1280..5750.8050.0.4190417StraidkillyS3.59105460672NC0.NC.47806360.367NCStraidkillytotal
0..672NC.70808750.8950.CastleCaldwellCC2.6150.0309.56605900.03740.0.121.75610000..551CastleCaldwellCC30.5960..336.75005710.8130.68605710.4710.0.CastleCaldwellCC50..41705840.05250.525.0200.77801420.0..125CastleCaldwelltotal.54505270..750.5710..53003350.3330579ElyLodgeEL10..4970.08330442.51103960.3270..667048908000.0.114ElyLodgeEL2.3840455NC0.NC.8800933NC.6390.0737.1830NCElyLodgeEL30.0..4550.6670.609.50904700.490ElyLodgeEL4.4920.65806480.04350.447.0601.0000569
1.ElyLodgetotal.44704960..0000.0.0.6460898.7690765.4620.6010598Meanbypopulation
0.507
.6000.0492
.5430521
0.870
0.737
0.552
0.497
0.339
OnlypatcheswithN≥5wereanalysed.
NC,Notcalculatedduetosmallsamplesize.
P,Two-tailedpairedt-testprobabilityvaluesfordifferencesinHEbetweenyears.*
2007forCo.Fermanaghpopulations,2009forCo.Antrimpopulations.2008forCo.Fermanaghpopulations,2010forCo.Antrimpopulations.
TABLE4.Analysisofmolecularvariance(AMOVA)forpopulationdifferentiationbylocation
Year1*
Year2
County
Location
%variation
P%variationPCo.AntrimStraidkilly
7..P,0.001Co.Fermanagh
.07P,00019.63CastleCaldwell1677P¼0.07518.ElyLodge
19.59
P,0.001
.76P,0.0011932
P,0.001
*2007forCo.Fermanaghpopulations,2009forCo.Antrimpopulations.2008forCo.Fermanaghpopulations,2010forCo.Antrimpopulations.
perfoliata(Kudohetal.,1999.);0.21,Parisquadrifoliavariationinrange-edgepopulationshasalsobeenreportedin(Jacquemynetal.,2005);033,Convallariakeiskei(Arakiotherclonalplantspecies(Lammietal.,1999;Billinghametal.,2007);0.43,Parisquadrifolia(Jacquemynetal.,etal.,2003;Jumpetal.,2003;Albertoetal.,2006;2006.);0.47,Mercurialisperennis(Vandepitteetal.,2010);Ecksteinetal.,2006).
083,Trilliumcuneatum(Gonzalesetal.,2008);0.84,ClonesinH.monotropaweresmall,extendingatmostoverAnemonenemorosa(Rusterholzetal.,2009);0.93,Violaafewtensofcentimetres.Inmostcases,theywerepairsofriviniana(Augeetal.,2001)].Thesehighlevelsofdiversityverycloselyspaced,adjacentMLGsasfoundinpreviousareinstarkcontrasttothoseobservedinOrthiliasecunda,studiesonotherclonalplantspecies(Haradaetal.,1997;anothermemberoftheMonotropoideaethatisrestrictedtoHoldereggeretal.,1998;Suzukietal.,2006).Inaddition,thesametwolocationsinNorthernIreland.ApreviousidenticalMLGswereneverfoundinterspersedwithotherstudyonthisspecies(Beattyetal.,2008)revealedthateachMLGs.Thus,themodeofclonalspreadinH.monotropapopulationcomprisedasingleclone.Bothspeciescurrentlywouldappeartoconformtothe‘phalanx’dynamic,whereexistinhighlyfragmentedpopulationsattheedgeoftheirclonesarecharacterizedbycompactgrowthforms,ratherrangesinthesameareasinNorthernIreland,butthanthe‘guerrilla’pattern,wherelongerrhizomesareinter-H.monotropaisprimarilyatemperatespecieswhereasmingled,givingrisetoclustersofdifferentramets(LovettO.secundagenerallyhasamoreborealdistribution.ItisDoust,1981;HumphreyandPyke,1998).Thesesmallclonesthuspossiblethatclimaticfactorshavein uencedtheswitchareagainincontrasttothoseobservedpreviouslyintoextensiveclonalgrowthinthelatterspecies.O.secunda,whereseverallargemonoclonalpatcheswereNevertheless,althoughH.monotropaexhibitedfarhigherfound,includingonecomprisedofapprox.600individualsdiversitythanO.secundainNorthernIreland,levelsofcoveringanareaofapprox.300m2(Beattyetal.2008).expectedheterozygosityweresigni cantlylowerthanthoseFurthermore,populationsofH.monotropainthepresentcalculatedfrompopulationsinthemainpartofthespecies’studydidnotappeartobecomposedoftheentirelysamedistributionrangeinEurope(Mann-WhitneyU-testP¼clonesacrossbothyearsofstudy,althoughtheoverall0.002;BeattyandProvan,2011).Suchadecreaseingenetic