CHANGESINBAYGALLVEGETATIONFROM1986TO2001 ATFORTPOLKINWESTCENTRALLOUISIANA CharlesM.AllenandJohn Pate SaraThames ColoradoStateUniv.,FortPolk OakRidgeInstituteforScienceandEducation 164523rdStreet 164523rdStreet FortPolk,Lomsiana71459,U.S.A. FortPolk,Louisiana71459,U.S.A. SpencerTrichelland LacyEzell DepartmentofBiology UniversityofLouisianaatMonroe Monroe,Louisiana71209,U.S.A. ABSTRACT BaygallsareaplanecommunityassociatedwiiiismallstreamsmwestcentralLouisiana.Plotsfrom a1986studyontheeffectsofsedimentationonbaygallvegetationwereresampledin2001.Nested subsampleswereusedandthesameareasweresampledduringeachtimeperiod.Importancevalues werecalculatedusingfrequency,mdividua!density,stemdensity,anddbh.In1986.thesedimented andcontrolbaygallsweresignificantlydiflcrcntinallvariablesexceptforwoodyindividualdensity andwoodystemdensity,in200f,dbhwastheonlyvariablenotsignificantlydiflerentbetweenthe controlandsedimentedbaygalls.Inthesedimentedareabetween1986and2001,thewoodyplant variablesincreasedwhileherbaceousplantvariablesdecreased.Woodyspecies,Liquidamhar styracij'iuuandAlnusscrrulatashowedalargedecrease,however,Toxicodendronradicans,Smilax rotundijohii,andJAsiustrumsinenseincreased.Inthecontrolbaygalls,fourfernspeciesincreasedin importancevalue. RHSUMEN Los"Baygalls"sonunacomunidadvegetalasociadaapequeiiostorrentesenelcentro-oestedeLuisiana. Lasparcelasdeunestudioen1986sobrelosefectosdelasedimentacionenlavegetacionbaygallse volvieronamuestrearen2001.Seusaronsubmuestrasanidadasysemuestrearonencadaperiodolas mismasareas.LosvaloresdeimportanciasecalcularonusandoIrccuencia,densidadindi\'idual, densidaddetallos,ydiametroalaalturadelpecho.Ln1986,losbaygallssedimentadosydecontrol fueronsignificativamentedilerentesentodaslasvariablesexceptoparaladensidadindividualde lenosasydensidaddetalloslenosos.En2001.eldiametroalaalturadelpechofuelalinicavariable nosignificativamentedilerenteentrcelcontrolylosbaygallssedimentados.Enelareasedimentada entref986y200f,lasvariablesdeplantasIciiosasaumentaronmientrasquelasvariablesdeplantas herbaceasdisminuyeron.LasespecieslenosasLiquidamharslyracifluayAlnusserrulatamostraron unagrandismmucion,sinembargo,Toxuadcndronradicans,Smilaxrolundijoha.yLiguslrum sinenseaumentaron.Enlosbaygallsdecontrol,cuatroespeciesdehelechosincrementaronsuvalor deimportancia. INTRODUCTION Baygallisacolloquialtermthatreferstothesmalldramagesystemsandtothe vegetationdevelopedalongthestreams(Allenetal.1990).Inthecenterofmost baygallsisasmallsandyorgravelly-bottornedstream,thatisintermittentin SIDA21(11:419-427.2004 420 BRIT.ORG/SIDA21(1) theupperdrainageandusuallycontinuousmthelowerportionsofthedram- age.Thesmallerstreamsdrainintoslightlylargerstreamsandultimatelyinto alargerwatercourse.Baygallsaresurroundedbypineforestsandarenarrowin theupperportiongraduallywideningdownstreamtoamaximumwidthof 20-50meters.Drainagefromthesurroundinguplandpmeforestpercolates downwarduntilitreachesanimperviouslayerofclayorrocktypicallyform- ingseepageareasthroughoutthebaygall.Pitcherplantbogsarefoundinopen areasinandalongtheedgeofmanybaygalls(Allenetal.1987).Thewoody vegetationmthebaygallsispredominatelybroad-leaved(dicotyledonous)de- ciduousorevergreentreesorshrubscontrastingwiththeverycommonever- green(gymnospermous)needle-leavedtreesoftheuplandpineforests.Theveg- etationdevelopedalongthefloorofthebaygallissparseandcontainsanumber ol ferns,bryophytes,especiallypeatmoss(Sphagnumspp.),andafewshade- tolerantfloweringplants. METHOD.S Inthesummerof2001,sixbaygallsusedina1986study(Allenetal.1990)were examinedforresampling.Thestudyareainoneofthesedimentedbaygallswas completelydestroyedandthusw^asexcludedfromresampling.Oneofthetwo transectsintwodifferentcontrolbaygallscouldnotberelocated.Twotransects wereresampledintheonesedimentedbaygallwithatotalof37subsamples. Fourtransectsin tourdifferentcontrol baygallswereresampledwith94 subsamples.The1986datafromthese37and94relocatedsamplesonlywere usedforcomparisonswiththe2001data. In1986,thestartingpointforeachtransectwasrandomlylocatedinthe centerolabaygallusingrandomnumbersandpacing.Thetransectextended perpendicularfromthebaygallstreamupslopetotheendofthebaygallveg- etationorsedimentedarea.Subsampleswereestablishedusingmetalpolesat onemeterintervalsalongthetransect.Mostoftheoriginalmetalpoleswere stillinplacealongthetransects.Inbothsamplingperiods,nestedsubsamples weretakenalongthetransectsateachoftheonemetermarkers.A0.09meter (0.3meterx0.3meter)quadratwasusedtosampletheherbaceousplants.The samplewastakenontheupstreamsideofeachpoint.Theshrubs(woodyplants withadbh(diameteratbreasthighatapproximately4.5feet)oflessthan4 inchesand/orshorterthan25feet)weresampledusinga1metersquarequad- ratwith1/2meteroneachsideofthetransectcenterline.Thetrees(woody plants4inchesdbhorlargerand/or25feetortaller)weresampledusing10 meterx1meterquadratwith5metersoneachsideofthetransectcenterline. Allspeciesandtotalnumberofstemswererecordedmeachquadratateach subsample.Thedbhwasrecordedtothenearest0.1cmforwoodytaxaofsuffi- cientheight Someol theherbaceoustaxacouldonlybeidentifiedtogenus,family ALLENETAL.,CHANGESINBAYGALLVEGETATIONATFORTPOLK,LOUISIANA 421 (PoaceaeorCyperaceae),orclass.DatawereenteredandanalyzedusnigMi- crosoftExcelsoftware.Thecommunityphysiognomyvariableswerecalculated bysummingthevalueforeachsubsampleanddividingbythenumberof subsamples,37forsedimentedbaygallsand94forcontrolbaygalls.Speciesrich- nesswascalculatedusingallplanttaxa.Individualdensity(numberofindi- vidualspersubsample)andstemdensity(numberofstemspersubsample)were calculatedforherbaceoustaxaandalsoforwoodytaxa.Thedbhwasalsocal- culatedforwoodytaxa. Thepopulationvariableswerecalculatedforalltaxabysummingthevalue foreachsubsampleanddividing by the numberofsubsamples,37for sedimentedbaygallsand94forcontrolbaygalls.Thefrequency(percentageof subsamplesofoccurrence)andmeanvalueforindividualdensityandstem densitywascalculatedforalltaxa.Themeanvaluefordbhwascalculatedfor thewoodytaxaofsufficientsize.Relativefrequency,relativeindividualden- sity,andrelativestemdensitywerecalculatedforallherbaceoustaxafromthe sedimentedbaygallsbysummingthevaluesforallherbaceoustaxainthe sedimentedareaanddividingthevalueforeachtaxonbythetotal.Therelative valuesforfrequency,individualdensity,andstemdensitywerecalculatediden- ticallyfortheherbaceoustaxafromthecontrolbaygallsandforwoodytaxa frombothcontrolbaygallsandsedimentedbaygalls.Allrelativevalueswere thenconvertedtoapercentage.Theimportancevalueforeachherbaceoustaxon wascalculatedbysummingthevaluesforrelativefrequency,relativeindividual density,andrelativestemdensityTheimportancevalueforeachwoodytaxon wascalculatedbysummingthevaluesforrelativefrequency,relativedbh,rela- tiveindividualdensity,andrelativestemdensity.Thetotalimportancevalue forallherbaceoustaxais300andforthewoodytaxais400. Mostplantswereidentifiedinthefieldbytheseniorauthor,andvoucher herbariumspecimensformosttaxawerecollected,mounted,andliledatFt. Polk.DuplicatesofmanyofthetaxaweredepositedmtheHerbariumofthe UniversityofLouisianaatMonroe(N1_U).Sometaxawereidentifiedmthelabo- ratoryusingAllen,(1980or1992);Correll and Correll(1972);Correlland Johnston(1970);Diggsetal.(1999);GodfreyandWooten(1979,1981);orRad- fordetal.(1968).ThescientificnamesarefromUSDA,NRCS(2002). RESULTS Themeanphysiognomycommunityvariables(speciesrichness,dbh,woody individuals,woodystems,herbaceousindividuals,andherbaceousstems)per subsampleforthesedimentedandcontrolbaygallsfor1986plus2001arepre- sentedinTable1.Thestandarddeviationisalsogiven.Thestudent'st-testwas usedtocomparevariablesbetweencontrol1986andcontrol2001,sedimented 1986andsedimented2001,control1986andsedimented1986,andcontrol2001 andsedimented2001.Allenetal.(1990)reportedthatt-testcomparisonsshowed 422 BRIT.ORG/SI0A21(1) Table 1.CommunityPhysiognomydata(SpeciesRichness,DBH,andDensity)incontrol(94 subsamples)andsedimentedbaygalls(37subsamples)for1986and200)atFortPolk,La.Allvari- ablesaresignificantlydifferentatthe0.05levelbetween:control1986andcontrol2001;sedimented 1986andsedimented2001;control1986andsedimented1986;andcontrol2001andsedimented 2001,exceptwherenoted.Standarddeviationisincludedinparentheses. ControlBaygalls SedimentedBaygalls 1986 2001 1986 2001 SpeciesRichness 4.79(2,36) 6.28(2.41) 7.32(2.67) 5.00(2.12) No.Woodyspecies 34 42 25 27 No.HerbaceousSpecies 24 23 34 3 DBH(cm) 17.16'^(23.54) 17.71'^''(21.94) 6.19(21.64) 14.19^15.30) WoodyIndividual Density 7.13'^(4.40) 12.80(5.94) 6.73'(4.34) 10.41(5.59) WoodyStem Density 8.10(5.05) 15,87(7.42) 7.3515.22) 11.32(6.14) HerbaceousIndividual Density 1.94"(3.05) 1.3811.64) 15.05(8.35) 0.16(0.55) HerbaceousStem Density 4.21'M7-82) 4.24"(6,10) 22.30(19.41) 0.19(0.62) 'Notsignificantlydifferentbetween1986and2001controlbaygalls ^Notsignificantlydifferentbetween2001controland2001sedimentedbaygalls ^Notsignificantlydifferentbetween1986and2001sedimentedbaygalls allvariablesbetweentbecontrol198(tandsedimented1986datatobesignitV cantlydiilerent.However,whenthedatafortherelocatedsamplesonlyareused, thewoodyindividualdensityandwoodystemdensitywerenotsignificantly dilferentbetweenthecontrolandsedimentedbaygallsin1986.Whenthecon- trol1986dataarecomparedtothecontrol2001data,thespeciesrichness,woody individualdensity,andwoodystemdensitywerethevariablesthatweresig- nificantlydifferent.Acomparisonofthe1986sedimenteddatatothe2001 sedimenteddatarevealsthatallsixvariablesaresignificantlydifferent,hithe 2001controlandsedimenteddata,dbhwasnotsignificantlydifierentwhile theotherfivevariableswereallsignificantlydifierent.InTable1,thevariables thatarenotsignificantlydifferentareindicatedby:'^ifbetween1986and2001 controlbaygalls;'^ifbctw^een 2001control baygallsand2001sedimented baygalls;and^'ifbetween1986controlbaygallsand1986sedimentedbaygalls. Themostdramaticchangesfrom 1986to2001occurredinthesedimented baygallswithgreatincreasesindbh(6.19cmto14.19cm),woodyplantindi- viduals(6.73to10.41),andvvcoodyplantstems(7.35to11.32).Largedecreases occurredinherbaceousindividuals(15.05to0.16)andherbaceousstems(22.30 to0.19). Theimportanccvaluesforeachwoodytaxoninthecontrolandsedimented baygallslor1986and2001areinTable2.In1986,thewoodytaxawiththehighest ALLENETAL.,CHANGESINBAYGALLVEGETATIONATFORTPOLK,LOUISIANA 423 Table2.Listofwoodytaxaandimportancevaluefromcontrolbaygallsandsedimentedbayqallsfor 1986and2001. 1986 2001 Taxon controlsedimented controsedimented Acerrubrum 17.87 22.27 17.06 7,54 AInusserrulata 0.00 18.32 4.27 0,00 Aroniaarbutifolia 5.59 1.74 8.52 0,00 Berchemiascandens 7.13 7.74 6.10 5,51 Bignoniacapreolata 1.12 0.00 8.22 15,03 Callicarpaamericana 2.50 1.74 4.83 2,11 Cephalanthusoccidentalis 0.00 26.42 0.00 0,00 Chionanthusvirginicus 0.56 0.00 1.19 0,00 Cornusflorida 0.56 0.00 0.35 0.00 Cyrillaracemiflora 0.00 0.00 0.70 0,00 Gelsemiumsempervirens 7.57 4.26 5.88 3.90 Hamamelisvirginiana 0.00 0,00 0.70 0,00 Hypericumspp. 0.56 1,74 0.35 0.00 Ilexcoriacea 22.45 0,00 35.00 3.08 Ilexopaca 7.91 1,74 5.62 0.00 Ileavirginica 1.68 26,94 4.94 0.00 Ligustrumsinense 0.00 7,74 0.00 47.47 Liguidambarstyraciflua 5.95 35,10 1.69 7.58 ionicerajaponica 0.00 0,00 0.00 6.51 Lyonialucida 23,00 0,00 33.72 0.00 Magnoliavirginiana 52,14 6.78 37.04 20.79 Morellacaroliniensis 19,61 1.74 13.62 1.05 Morellacerifera 4.76 16.27 0.65 22.91 Nyssasylvatico 78.30 148.97 51.69 69.28 Parthenocis'iUsguinquefolia 0.00 0.00 0.35 0.00 Perseapalustris 23.37 1.74 24.50 3.16 Pinuspalustris 0.00 0.00 2.76 0.00 Pinustaeda 22.15 2.52 22.64 49.00 Quercusalba 0.00 0.00 1.34 0.00 Quercustalcata 0.56 0.00 0.00 0.00 Quercusnigra/laurifolia 4.73 22,51 6.95 9.32 Quercusseedling 0.00 0,00 0.35 0.00 Rhododendronspp. 7.12 0.00 4.85 0.00 Rhuscopallina 0.00 1.74 0.35 0.00 Rubusspp. 8.13 6.96 18,60 2,11 Salixnigra 0.00 9.85 0,00 0,00 Sassafrasalbidum 1.12 0,00 0.00 0,00 Smilaxglauca 5.88 0.00 8.92 1,05 Smilaxlaurifolia 9.46 0,00 8.32 6,27 Smilaxrotundifolia 28.43 4.26 5.52 23,70 Smilaxsmallil 0.00 0.00 1.46 0,00 Smilaxtamnoides 0.00 0.00 0.00 1,05 Toxicodendronradicans 9,24 16.64 21.31 60,40 Toxicodendronvernix 1.68 0,00 0.85 1.05 424 BRIT.ORG/SIDA21(1) Table2.continued 1986 2001 Taxon controlsedimented controlsedimented Vacciniumarboreum 0.00 0.00 0,00 1.55 Vacciniumcirkansanum 1.12 0,00 0,91 0.00 Vacciniumelllottii 1.96 0,00 2.30 2.11 Viburnumdentatum 4,33 4,26 4.23 18.32 Viburnumnudum 11.45 0,00 20.69 8.17 Vitisrotundtfolia 0.00 0,00 0.70 0,00 importancevalue(>20.00%)inthecontrolbaygallswereNyssasylvatica,Mag- noliavirginiana,Smilaxrotundifolia,Perseapalu<.tris,Lyonia lucida,Ilex coiiacca,andPinustaedaandin2001,thetoptaxawereNy^sasylvatica,Mag- noUayirginiana,llexcoriacea,LyoniaJucida,Perseapalustns,Pinustacda,Toxi- codendwnradicans,c\ndViburnumnudum.Inthesedimentedbaygallsin1986, themostimportanttaxonwasNyssasylvaticawithanimportancevalueof 148.97%,whichwasalmostfivetimesasmuchasthesecondmostimportant taxon.In2001,Ny.s.scisylvaticawasstillthemostimportanttaxon,butitsmi- portancevaluewasonly69.28%.Inthesedimentedbaygallsm1986,othertaxa withimportancevaluegreaterthan20.00%wereLitfiadumi'wr.sfyrtul/hai.ItM virginica,Cephalanthusoccidentalis,Quercusnigra/laurifolia,andAcer ruhrum.Inthesamesedimentedbaygallsin2001,thetaxawithmorethan 20.00%importancevaluewereToxicodendronradicans,Pinustaeda,Ligustrum sinensc,Smilaxrotundifolia,Morellacerijera,andMagnoliavirginiana. Theimportancevalueforeachherbaceoustaxonmthecontrolbaygalls lor1986and2001areinTable3.In1986,thetaxonwiththehighestnnportance valuewasPoaceaefollowedbyRudbeckiascabrifolia,Dichantheliumtenue, Violaprimulifolia,andherbaceousdicotyledons.In2001,thefivetaxawiththe highestimportancevalue(indecreasingorder)wereDichantheliumtenue, Woodwardiaaerolcita,Rudbeckiascabrifolia,Carexleptalca,andChasmanthium laxiim. In 2001,there wereonlythree herbaceoustaxaobservedin the sedimentedbaygalls(Poaceae137.91%,Chasmanthiumlaxum108.06%,and Mitchellarepens.54.03%);thiscontrastedtremendouslywiththe43taxare- cordedm1986mallsubsamplcs(Allenetal.1990)andthe34taxaintherelo- catedsubsamples.Thetaxawith thehighestimportancevaluein1986were Poaceae,Lycopusspp,,1lerbaceousdicotyledons,/uncusdifjusissimus,andJuncus coriaceus. C0NCLUS10N.S In1986,thedataindicatedthatsedimentationhadasignificanteffectonthe baygallvegetationcommunityThestudent'sttestshowedlourvariablestobe . ALLENETAL.,CHANGESINBAYGALLVEGETATIONATFORTPOLK,LOUISIANA 425 Table3.Listofherbaceoustaxaandimportancevaluefromcontrolbaygallsfor1986and2001 Taxon 1986 2001 Apteriaaphylla 1.89 0.00 Arisaematriphyllum 3.78 8.46 Arnoglossumovata 0.00 3.47 Athyriumfelix-femina 4.01 9.62 Carexfolliculata 0.00 15.72 Carexleptalea 0.00 24.50 Chasmanthiumlaxum 4.97 17.74 Coreopsisgladiata 10.19 0.00 Cyperaceae 2.70 6.42 Dichantheliumacuminatum 0.00 2.95 DichantheHumcommutatum 1.89 0.00 Dichantheliumdichotomum 0.00 4.22 Dichantheliumtenue 43.36 61.67 Erechtiteshieracifolia 1.89 0.00 Eupatoriumleucolepis 0.00 2.20 Eupatoriumrotundifolium 1.89 0.00 Herbaceousdicot 27.29 0.00 Lachnocaulonanceps 3.50 0.00 Lobeliareverchonii 1.89 2,20 Lycopusspp. 0.00 2.20 Melanthiumvirginicum 2,65 0,00 Mitchellarepens 14.29 16,32 Osmundacinnamomea 5.80 10,32 Poaceae 47,72 2.20 Rhynchosporarariflora 4.72 0.00 Rudbeckiascabrifolia 43.98 29.89 Selenaoligantha 0.00 2.70 Solidagopatula 1.89 9.39 Symphyotrichumspp. 0.00 4.23 Violapnmulifolia 42.30 9.07 Woodwardiaareolata 16.42 52.29 Woodwardiavirginica 1.89 2.20 Xynsspp. 9.08 0.00 highlysignificantlydifferent between thescdimentedandcontrolornon- sedimentedbaygalls.Speciesrichnessandherbaceousindividualsandstems hadincreasedinthesedimentedbaygallswhilethedbhhaddecreased.Sedi- mentationhadkilledmanyofthelargerwoodyplantswhichexplainedthe decreaseinthedbh.Theincreaseinspeciesrichnessandherbaceousindividu- alsandstemsprobablyoccurredbecausetheadditionofsedimentationcre- atedamoremesichabitat. Whenthetwoareas(controlandsedimented)werecomparedagainin2001, thedbhhadincreasedmthesedimentedbaygallsandwasnolongerdifferent 426 BRIT.ORG/SIDA21(1) (TableI).Acomparisonofthesedimentedarea1986datatothe2001datare- vealedthatthespeciesrichnesshaddecreasedIroin7.32to5.00speciesper sample.Thenumberofwoodyindividualsandstemshadalmostdoubledand thedbhhadmorethandoubledinthescdmnentedbaygalls.Thebiggestchanges inthesedimentedbaygalIsoccurredwiththeherbaceousplantswherethemean numberofindividualsdecreasedfrom15.05to0.16andthemeannumberof stemsdecreasedfrom22.30to0.19stems.Thesechangesmthesedimented baygallindicatethatthisareaischangingfromanopenareatoaforestedarea. Theincreaseintreesandshrubshascreated moreshadeandcausedalarge decreaseinthenumberofherbaceousplants.Thenumberofherbaceousspe- ciesdecreasedfrom34to3. hithecontrolbaygallsbetween1986and2001,speciesrichness,woody individuals,andwoodystemshadallincreasedsignificantlyandthedbh,her- baceousindividuals,andherbaceousstemshadremainedfairlyconstant.These changesandlackofchangecouldbeattributedtonormalsuccessioninthe baygalls. Nyssasylvaticaisatreethatseemstobelittleaffectedbysedimentation,as itsimportancevalueisveryhighinthesedimentedbaygallsin1986(T.tble2). Thetree{LiquidcunharstyraiiJlua),shruhs(Alnusscrnilata-dndCcphalanthus occidcntalis),andvine^Toxicodendron nidiccins)seemtogrowbetterinthe sedimentedareasasindicatedbytheincreaseintheirvalues.Treespecies(Mt;t,'- noliuvirginiunaandPinusidcdu),shrubspecies{PcrseapalustrisundIlex COriacea),andthevine{SmilaxrotundifoliLi)seemtohavebeenaffectedbysedi- mentationastheirvaluesdecreasedinthesedimentedbaygall.In2001inthe controlbaygalls,theshrubs(IlexcoriaceaandLyonialucida)hadincreasedin importancevalueandisprobablylinkedtonaturalsuccessioninthebaygalls. Thesedimentedbaygallshadundergonemoredramaticchangesbetween1986 and2001whereearlysuccessionalspecies(Liquititim/wrs/yracif/uc;andA/nu.s serrulata)showedatremendousdecreaseinimportancevalue;Alnusserrulata wascompletelyabsentin2001andlAquidamharstyracifluadecreasedfrom animportancevalueof35.10%to7.58%.Theshadetolerantvines{Toxicoden- dron radicansi\nc\Smilaxrotundijolia)increasedgreatlyinimportanceval- ues.Theintroducedspecies{Lii^ustrunisinense)hadalargeincreaseinimpor- tancevaluefrom7.7T%\n1986to47.47%in2001.Mostofthesechangesseemed tobelinkedtosuccessioninasedimentedareaexceptfortheintroducedspe- ciestillinginthenichesnormallyoccupiedbynativeshrubs. Thenotablechangeintheherbaceoustaxain1986wastheincreaseinthe numberolweedytaxamthesedimentedbaygallsthatwerenotpresentmthe controlareasorwerepresentmsmallnumbers(Allenetal.1990).Someofthe weedytaxaincludeseveralspeciesoijuncusandSolida^o,Diodiateres,Ambro- siaartemisiifolia,andBidensarislosa.Thecreationofa newhabitatmthe sedimentedbaygallsisthereasonfortheinvasionbytheweedytaxa.Allofthe ALLENETAL.,CHANGESINBAYGALLVEGETATIONATFORTPOLK,LOUISIANA 427 {erns(Athyriumfelix-femina,Osmundacinnamomea,Woodwardiaaerolata,and Woodwardiavirginica)werenotfoundmanyoftfiesedimentedsamplesbut werepresentinthecontrolsamples.Allfourshowedanincreaseinimportance valuebetween1986and2001mthecontrolbaygalls.Theferntaxainthe sedimentedbaygallsin1986apparentlydecreasedbecauseofincreasedsun exposurecausedbythedeathoftreesinthebaygall.Thesefernspeciesprob- ablyincreasedinvalueinthecontrolbaygallsinbetween1986and2001asa resultofincreasedshade.In2001,thesedimentedbaygallschangeddramati- callywithvirtuallynoherbaceousplantspersisting.Thedenseshadeproduced bythetreesandshrubsgreatlydecreasedthenumberofherbaceousplants, especiallyweedyspecies. 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