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Seed and Seedling Ecology of Neotropical Melastomataceae

Author(s): Aaron M. Ellison, Julie Sloan Denslow, Bette A. Loiselle, Danilo Brens M.Reviewed work(s):Source: Ecology, Vol. 74, No. 6 (Sep., 1993), pp. 1733-1749Published by: Ecological Society of AmericaStable URL: http://www.jstor.org/stable/1939932 .

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Ecology, 74(6), 1993, pp. 1733-1749(?) 1993 bytheEcological Society of America

SEED AND SEEDLING ECOLOGY OF NEOTROPICALMELASTOMATACEAE'AARON M. ELLISONDepartment f Biological Sciences, MountHolyoke College, Clapp Laboratory,SouthHadley, Massachusetts 01075-1484 USA

JULIE SLOAN DENSLOWDepartment f Ecology, Evolution, nd Organismal Biology, Tulane University,New Orleans, Louisiana 70118 USABETTE A. LOISELLEDepartment f Biology, Universityf Missouri, 8001 Natural Bridge Road,St. Louis, Missouri 63121 USADANILO BRENtS M.Organizaci6n para Estudios Tropicales,Estaci6n Biol6gica La Selva, Apartado 676,2050 San Pedro de Montes de Oca, Costa Rica

Abstract. Models of gap-phase regenerationntropicalwet forests re based primarilyon studies of canopy trees. These paradigms are derived from tudies ofa small numberof species whose life history raitsplace them easily into "pioneer" or "climax" species.Woody plants of the forest nderstory, ubcanopy trees and shrubs, re knownto affectsignificantlyegeneration ynamics n treefall aps, yetwe lack fundamentalnformationon lifehistory haracteristics f understory lants thatcould permittheir ncorporationinto gap regenerationmodels. We investigated ntra- nd interspecific ariabilityn earlylifehistory haracteristics f understoryMelastomataceae species of differentrowth ormsand adultdistributions rom he owlandtropicalrain forest t La Selva BiologicalStation,Costa Rica. We examined germination atternsnvitro 22 species),effectsngerminationof passage throughbirds (5 species), seedling establishmentn the field 3 species), andgrowthn differentight nvironments 8 species).Establishedseedlingswere significantly ore abundant in gaps than n nearbyunder-story ites. This patternwas generally pplicable to all melastomesstudied, regardless fthehabitat where adults were normallymost abundant. Seedlingsweremore common intheroot pits and on theroot mounds of uprooted trees, ven though herewas less lightavailable to the seedlings n these microsites han elsewhere n the gaps. In a series ofgermination rials n vitro,mostseeds germinated eadilywithin1-2 wk.Comparisonsofgermination ates between seeds collected frombirddroppings nd seeds extracted romfruits y hand gave varied results. With one exception, seeds of shade-tolerant peciesgerminatedmore slowly followingpassage throughbirds,while seeds fromhigh-light-demanding species germinatedmore rapidly fter assing through irds.Seeds of three ommon species were sown directlyntodifferent icrositeswithin apsand understory ontrol ites. n contrast o the germination rials, mergencepercentagesin the fieldranged from4% in understory ites to 21% in gap centers. urvivalafter1 yrwas low (0.1%-0.4%). After1 yr,these seedlings were small (

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1734 AARON M. ELLISON ET AL. Ecology, Vol. 74, No. 6INTRODUCTION

The ability of buried seeds and suppressedforestseedlings to respond rapidlyto increased light evelsfollowing treefall as longbeen recognized s a crucialstage n plant ife history, nd is a fundamental om-ponentof stand regenerationn tropicalforests e.g.,Schulz 1960,Vdzquez-Ydnes 1974, Ng 1978,Denslow1980, 1987, Clark and Clark 1987). Seed size, germi-nation rates, nd establishment trategiesmong trop-ical trees re diverse Ng 1978,Whitmore1983, Fosterand Janson1985, Foster1986, Swaine and Whitmore1988, Garwood 1989). "Pioneer" (sensu Swaine andWhitmore1988), or gap-dependent species, such asCecropia pp. Cecropiaceae),Ochroma agopusSwartz.(Bombacaceae), and Heliocarpus ppendiculatus urcz.(Tiliaceae), have small seedswithextendeddormancyand rapid germination nd growth n responseto in-creasing ight evels (Vdzquez-Ydnes 1974, Moreno-Casasola 1976, Holthaijzen and Boerboom 1982,Nfiiiez-Farfannd Dirzo 1988). "Climax" or "non-pioneer" species (sensu Swaine and Whitmore 1988),on theotherhand, tendto have larger eeds with ittledormancy, nd rapid germination ollowing ispersal(Foster 1986). Many tree species fall between theselimits, ombiningrapid germination nd some shadetolerance with rapid growth esponses following an-opy opening Clark and Clark 1992).Data on seed and seedlingecology of species notencompassedby the pioneer and climax categories rescant,however.n commonusage, hese ategories avebeen applied only to canopy or emergent rees,andconsequently o not ncludethediversityfplant ypesthatmakeup anyforest.n particular, nderstory pe-cies, shrubs nd small treelets, re ubiquitousin trop-ical forests, an inhibitregeneration f canopy trees(Brokaw 1983, Raich and Gong 1990, Denslow et al.1991), and yet have been studied rarelyrelative tocanopytrees.Detailed studiesofearly ifehistory rop-erties, uchas germination, stablishment,nd seedlinggrowth f understory pecies are therefore eeded tocomplement he relative wealth of comparable infor-mation vailable for anopytree pecies,and topermitmore reliable predictions f regeneration ynamics nwet tropicalforests.Combinations ofearly ifehistory haracteristicsnunderstorypeciesmaydifferrom hoseoutlined boveforrain forestpioneerand climax canopy trees.Forexample,Vdzquez-Ydnes and Or6zco-Segovia (1984)foundthatalthough eeds ofmanyunderstory peciesexhibit enforceddormancyand requiregaps forger-mination, thershave rapidpostdispersal erminationand nodormancy egardlessf ight nvironments.Withregardto germination nd seedling establishment, thas been suggested hatunderstorypecieshave a widerecological amplitude e.g., Lebr6n 1979) and are lessdependenton gaps than are canopy trees Hartshorn1978,Lebr6n 1979, Brokaw 1985). Understorypeciesare likelyto recruit nto new gaps eitherfromsup-

pressed seedlingsor as seeds dispersed nto gaps fol-lowinggap creation Garwood 1983, Lawton and Putz1988, Levey 1988a), but appear to not require gapformation o germinate. This is because understoryspecies oftenproduce fewer eeds, and their eeds areless abundant n the eed bank than re seeds ofpioneertrees (VAzquez-YAnes 1974, Uhl and Clark 1983,Whitmore 1983, de Foresta and Prevost 1986, Gar-wood 1989;but see Alvaraz-Buylla nd Garcia-Barrios1991).In contrast, urvival and growthof seedlings andolder plantsmay be influencedmore strongly y gapenvironments han s seedlinggermination. rowthofunderstorypecies is generally ighest n gaps relativeto other nvironmentsDenslowet al. 1990),and shrubsflower nd fruitmore abundantlyn gaps (Croat 1975,Stiles1975,Levey 1988a). This concentrationf fruitsingaps has led Levey 1990) to conclude thatgaps maybe "keystonehabitats"forfrugivoresn tropicalrainforests.Gaps (sensu Brokaw 1982) themselvesare not ho-mogeneous, but encompass substantialvariation inlight, emperature,moisture, oil, and nutrient rop-ertiesPutz 1983, Nutfez-Farffannd Dirzo 1988, Poul-son and Platt 1989, Peterson t al. 1990). Ifunderstoryspeciesare not strictly ependent n gapsfor uccessfulrecruitmentHartshorn1978, Lebr6n 1979, Brokaw1985), then seed germinationmay be less sensitivetomicroenvironmental ariationwithin a gap. That is,we would not expect great ntraspecific ariation ingermination nd establishmentn differentartsof atreefall ap.Later seedling growth,however, should be influ-enced more strongly y gap microsite,but data ad-dressing hisprediction re rare.Denslow etal. (1990,and unpublishedmanuscript)found significant e-sponsesto within- nd between-gapvariation n lightavailability,butnotnutrients, mong rootedcuttingsof severalspecies n the Melastomataceae and thePip-eraceae. As a complementto these long-termtudiesof theresponsesofunderstory pecies to treefall aps(Denslow et al. 1990, Denslow et al., unpublishedmanuscript), eexamined ndetail theecology f eedsand seedlings f a number f melastome pecies nandaroundgaps,and incontrolledight nvironments.Weasked sevenspecific uestionsconcerningheearly ifehistories f thesespecies:

1. What are thegermination ime coursesofnewlydispersedmelastome seeds?2. Does passage through irds affect ermination?3. How is the frequency f successful eedlinges-tablishmentnthe field ffectedy gapmicrosite?4. Are melastome seedlingsmore common in gapsor in surrounding orest?5. What s thedegree f ntra- nd interspecificari-ation in distribution nd abundance patterns ftheseseedlingswithin reefall aps?

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September 1993 MELASTOMES IN A NEOTROPICAL RAIN FOREST 17356. How do light onditions, epresentativef ntactforest,gap edges, and gap centers, ffect arlyseedlinggrowth?7. What is the interspecific ariation in these lifehistory arameters, nd how does thisvariationrelate to plant ife-formnd adultdistribution?

STUDY SITEAll field work was conductedat the La Selva Bio-logical Station 10028'N, 8359' W) oftheOrganizationforTropical Studies. This is a reserveof premontanewet tropicalforest sensuHoldridge et al. 1971) in theAtlantic owlands of Costa Rica (see Hartshorn1983for more detailed description).Average annual rain-fall s -4000 mm, with a less rainy eason fromJan-uary throughApril, when averagemonthly ainfall s

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1736 AARON M. ELLISON ET AL. Ecology, Vol. 74, No. 61 00.8 -- - - - Species ofdisturbed areas:0.6 - V 0 N. aquatic* Co. subcrustulata04 Y~~~~~~VV v M. fomgfolia? 4 - |o Cc.dentata/ v M. barbinervis0.2 - //

V'?I *+O V0.01.0

z 0.8F- wv * -v *High-lightli 0.6 k /forest species:

* L. mexicanaZ 04 -v M. affinisO L. dichotoma02-

1.0 Low-lightforest species:0.8 JA_ _7.8 -Vt-V-VV V ; _=C. discolorI I 7/1 ' * C. apurensis0.6 - A M. simplexL,, M. rtervosa0.4 - 0 C. crenulata7111 I / v L. consimilis*0. milcrantha0.2

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September1993 MELASTOMES IN A NEOTROPICAL RAIN FOREST 1737exceptionsof Leandra dichotomy nd Miconia barbi-nervisFig. 1), ofwhich< 20% ofthe seedsgerminated.To examine statistically hedifferencesn germina-tionratesbetween pecies commonto abandoned pas-tures,high-light pecies of the forest, nd shade-tol-erant pecies Fig. 1), we divided each of these speciesgroups nto two sub-groups: hosewith time to 50%germination 10 d; and thosewith time to 50% ger-mination> 10 d. Therewereno significantifferencesin germinationimes mong thethree roupsof pecies(X272 =1.30; P > .50, G test).

PATTERNS OF GERMINATION: EFFECTS OFBIRDS ON SEED GERMINATION

MethodsMany melastome fruits re eaten by birds, whichalso disperse their eeds (Denslow et al. 1986, Levey

1988a, b, 1990, Denslow and Gomez-Diaz 1990, Loi-selle and Blake 1990). Passage through irdshas beenthoughto enhance eedgermination,ut experimentalstudieshaveproducedmixed results Izhaki and Safriel1990). We thereforelso investigated he ffectsf fruitconsumption y birdson seedgermination ates ques-tion2, see Introduction).We collected dditional fruitsof Clidemia densiflora, onostegia subcrustulata,Mi-conia affinis, . simplex, nd Ossaea macrophylla, ivespecies thathad exhibited disparate responses n thegermination experiments in vitro.In those experiments, onostegia subcrustulata ndM. simplexhad germinated eadilyand rapidly,withtotal cumulative germination pproaching100%. Wethereforeypothesizedhat assage through irdswouldnot enhancefurther,r might ven inhibit erminationof these two species. M. affinis nd 0. macrophyllagerminatedmoreslowly nd lessreliablynthe nvitrotrials, nd for hese two specieswe hypothesized hatpassage through irds could marginally nhance ger-mination.Clidemia densiflora id notgerminate t allin the in vitro trials, nd we predicted hat birdcon-sumption would dramaticallyenhance germinationfrequency nd rateof C. densiflora eeds.Fruitsof each specieswerefedto Red-capped Man-akins Pipramentalis) aught nmistnets Loiselle andBlake 1991). Seeds were then separated fromfreshdroppings nd placed into petridishes on moistenedfilter aper.For controls, eeds were handledas in thein vitro germinationexperiments. ndividual petridishes containedeitherthe seeds fromone dropping(1-7 replicates), r the seedsfrom ne intactfruitcon-trols, -3 replicates).Germinationwas scoreddailyfor6 wk,with the exceptionof C. densiflorawhichwasfollowedfor16 wk.We plottedthe mean cumulativeproportion overall replicates feach species) of seeds thatgerminatedafter onsumptionby birds on the abscissa, and themean cumulativeproportion f control eeds thatger-minated on the ordinate. Each point of the plot rep-

resents successive day, with time proceeding fromthe bottom eft ornerto the top right orner of eachplot. We used a least squares linear regressionmodelto fit line through hese points. If the slope of thisline was not significantlyifferent rom 1, then weconcluded that therewas no differencen cumulativegermination requency etween treatmentst any giv-en time. Significant eviations from slope of 1 in-dicated that thecumulative germination requency fseeds from fruits onsumed by birds increased morerapidly slope > 1) or ess rapidly slope 1). Also consistentwithourhypothesis, eedsof M. affinis rombird droppingsbegan germinatingearlier than controlseeds. However, cumulativeger-minationfrequencyf control eeds increased t a sig-nificantlymore rapid rateonce germination ad com-menced (quadratic regression, polynomial-termcoefficient 1). The germination ehavior of Ossaeamacrophyllawas similar n all respectsto that ofM.simplex.

GERMINATION AND ESTABLISHMENT IN THE FIELDMethods

Our results from the above studies indicated thatgerminationpotentialof melastome seeds was rela-tively high.We thereforenvestigated he correspon-dence of these resultswith seed germination nd es-

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1738 AARON M. ELLISON ET AL. Ecology,Vol. 74, No. 61.00 Clidemia densiflora ,' Conostegia subcrustulata ,'

z 0.75< ,~~~~~~~,

0.50 " 1XE- 1.00 rFcniap~,,**e m~107' 1 oI. /= 0.25

CI) 4~~~~~~~~~~~~~~~~~00.000 0.! 5 00.

F 2 1.00 Micomia g o 29t Ossaeea macrophylla0

10 /~~~~~40 0.25/

o 015~~~~~~~~~~~~~~~~~~~~~~~~~~~10.500

0.00 0.25 0.50 0.75 1.00 0.00 0.25 0.50 0.75 1.00CUMULATIVE FRACTION OF CONTROL SEEDS THAT GERMINATED

FIG. 2. Comparison of cumulativegermination hrough ime of melastome seeds passed through irds relative o pairedcontrols.Each pointrepresents singleday; for clarity, umbers ndicate particulardays after he startof thegerminationtrials. The best-fit egression ine through he pointsis plotted ) along with its 95% confidence nterval ). Thedashed line slope = 1) is providedforreference. ee Patterns f germination: ffects f birds . : Methods for nterpretationand statistical iscussion.tablishment n the field, nd examined the effects fdifferentight nvironments n seedlingemergencengaps (question 3, see Introduction).

Seeds of Miconia affinis, . gracilis, nd M. nervosawere xtracted rom ruits s inthe nvitrogerminationexperiments,but instead of being stored dry,wereplanted within2 d of collection directly nto recentgaps < 1yr ld) createdbythefallof ingle rees.Three"replicate" gaps were used in thisexperiment, ll onthe same soil type Jaguarconsociation; Sancho andMata 1987) onridge ops.Three ight reatmentsplots)were establishedwithin ach gap. In the center feachgap, vegetation 2 m tall was cleared from 5 x 5 mplot to createthehigh-lightreatment.n themid-lighttreatment,eeds were planted n a 5 x 5 m plot withinthegap where the low vegetationwas left ntact.Thelow-light reatment eeds wereplanted into 5 x 5 mplots in the adjacent forestunderstory.n each plot,

we established three 100 x 75 cm quadrats. In eachquadratwe removed the itter nd planted25 seeds ofeach species 2mmbeneath he oil. Seeds wereplant-ed 3 cm apart in threerows separatedby 20 cm. Intotal, we planted 675 seeds of each species: 75 seeds(threereplicate uadrats) ofeach species in each lighttreatmentn each site.Seeds were sown in September1988, and quadratswere sampled once every2 wkfor1yr.At each samplingdate, all seedlings hatemerged(cotyledonsvisible above the soil) were noted andmarkedwith smallplastic stakeadjacent to the seed-ling. Height ? 1 mm) and number of leaves werere-corded. Plots wereweeded once every2 wk.Annual incidentdirect and indirect unlight t 50cm above each quadrat was estimated fromhemi-spherical anopy photographs Rich 1988, 1989) takenwith 7.5 mmfisheyeMinolta lens. Photographsweretaken 1wk after heseeds were sown.Negativeswere

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September 1993 MELASTOMES IN A NEOTROPICAL RAIN FOREST 1739TABLE 1. Seedlingemergence nd survivalof Miconia affinis,M. gracilis, nd M. nervosa own into gaps and understorysits.

Withingaps In forest nderstoryVegetationremoved to 2 m Low vegetation ntact Vegetation ntact

Number Number NumberEmergingsurviving

Emergingsurviving Emerging survivingSpecies No. % after1 yr No. % after1 yr No. % after1 yr

M. affinis 9 12 0 6 8 0 7 9 1M. gracilis 21 28 1 14 19 0 6 8 0M. nervosa 19 25 3 5 7 0 3 4 0digitized nd analyzed for stimated nnual direct itefactor DSF) (directbeam radiation) and indirect itefactor ISF) (reflected kylight) s a proportion ftotalincident sunlightusing softwaredeveloped by Rich(1989, Rich et al. 1993). The global site factorGSF;equivalent to the total site factorof Anderson 1964)is a weighted sum of DSF and ISF (0.45 DSF +0.55 ISF; Rich et al. 1993). These measures of lightavailability re strongly orrelatedwith vailable pho-tosyntheticallyctive radiation PAR) and/orphoto-synthetic hotonflux ensity PPFD) as measuredwithquantum sensors Rich et al. 1993).

ResultsThe light nvironmentsneach treatment ere sim-ilar neach of thethree ites nto whichMiconia seedswere sown. GSF was 0.10 ? 0.009 (mean + 1 SE, n =3) inthe high-lightreatment, .05 ? 0.029 in the mid-light treatment, nd 0.006 ? 0.003 in the low-lighttreatment. mergenceof seedlings n the three ighttreatmentswas low relative to the numberof seedssown Table 1). Cumulativeemergence fter yrofallspecieswas highest n the high-lightreatmentssec-ond-growth egetation emoved)and lowest ntheun-derstoryTable 1), and therewere no between-speciesdifferencesnemergencewithrespect o thethree ightenvironmentsX24 = 6.85, .5 > P > .1). Overall,totalemergence pooled over the threespecies) increasedwith ncreasing ight X22 = 19.39, F < .001).In total,onlyfive eedlingsremained live after yr(Table 1).Results repooled for hethree ites nTable

1. All were

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1740 AARON M. ELLISON ET AL. Ecology, Vol. 74, No. 6TABLE 2. Total number with% oftotal) ofMelastomataceae seedlingsfound n natural reefall aps and understoryontrolsites.

In gaps In understorySpecies No. % No. %

Adelobotrysdscendens SW.) Triana 0 0.0 1 4.8Clidemia discolor Triana) Cogn. 5 1.4 0 0.0Clidemia ephiphyticaTriana) Cogn. var.trichocalyxBlake) Wurdack 7 1.9 0 0.0Conostegia setosa Triana 10 2.7 4 1.6Henriettea uberculosaDonn. Sm.) L. 0. Wms. 1 0.3 0 0.0Leandra dichotoma D. Don) Cogn. 21 5.7 2 8.0Leandra granatensisGleason 4 1.1 0 0.0Miconia affinis C. 41 11.1 5 23.8Miconia appendiculata Triana 0 0.0 1 4.8Miconia centrodesmaNaud. 0 0.0 1 4.8Miconia gracilisTriana 15 4.1 1 4.8Miconia multispicataNaud. 168 45.7 3 14.3Miconia nervosa J.E. Smith) Triana 34 9.2 1 4.8Miconia punctata Desr.) D. Don ex DC. 0 0.0 1 4.8Miconia serrulata DC.) Naud. 4 1.1 0 0.0Miconia simplex Triana 42 11.4 0 0.0Miconia stevensianaAlmeda 2 0.5 0 0.0Ossaea macrophyllaBenth.) Cogn. 0 0.0 1 4.8Triolenahirsute Benth.) Triana 14 3.8 0 0.0Total 368 21

cover was not assumed to vary as widely n the un-derstory. hotographswere analyzed as described inthe field ermination xperimentsee Germination ndestablishmentn the ield:Methods).Results

Overall, melastome seedlings were 20-fold moreabundant in gaps than in correspondingunderstorysites Table 2). Of those species consideredhigh-light-demanding (Appendix 1), only Miconia affinis ndLeandra dichotomaoccurred n the gaps thatwe sam-pled. The other high-light pecies listed in Appendix1are more ypical fhighly isturbed reas abandonedpastures ndriverbanks), nd are not common n smallgaps within heforest.n total, 68 seedlingswerefoundin the 10 gap sites 24.9 ? 9.89 seedlings/M2X ? 1SE] overall gap sites),whileonly21 total eedlingswerefound in the 10 paired understory ites (1.1 ? 0.27seedlings/M2 over all control sites) (t9= 2.32, P = .045,paired t test). Of the 19 species encountered,14 weremore common in gaps than in the understory. heother ive pecieseach wererepresented yonly singleindividual. Among the seven gaps in whichmelastomeseedlingsoccurred, he numberof seedlings ncreasedsignificantly ithgap age (r2 = 0.69, F1 6 = 13.15, P= .01).In these sites,we examinedin more detail theseed-lingdistribution atterns f the more commonspecieswhose abundance permitteddetailed statistical nal-ysis: Leandra dichotoma,Miconia affinis,M. gracilis,M. multispicata,M. nervosa, nd M. simplex.All spe-ciesexceptM. graciliswere ignificantly orecommonin treefall aps than in the forestunderstory Fig. 3,Table 3). To examine differencesn seedling abun-

dances amonggap microsites,we analyzedwithin-gapabundance patterns singG tests on two-way ontin-gencytables, where the six rows were ocationwithingap (pit,mound,bole, and transects t + 1 m, + 5 m,and ? 10 m) and thecolumns were og2seedlings/M2.Degrees offreedomforeach G testare givenby (row1) x (column 1), where row 1) = 5, and (column 1)variesbetween1and 3, depending n the actualnum-ber ofnon-zero eedling ategories.Mean (? 1SE) num-berof seedlings n each within-gap ampling ocationare shownin Fig. 3.All six ofthesespecies weremoreabundant n rootpits and mounds than elsewherewithin gaps. Thesedifferences ere significantn the cases ofM. affinis(X2 = 23.15, df= 10, P = .01), M. multispicataX2 =31.38, df= 15,P = .008), and M. nervosaX2 = 15.12,df= 5,P = .009). The other peciesshowed a tendencytowards greater bundance in root pits and on rootmounds M. gracilis:X2 = 17.98, df= 10, P = .06; L.dichotoma:X2 = 10. 1, df= 5, P = .07; M. simplex:X2 = 8.08, df= 5, P= .15).Overall, seedings were not distributedrandomlywithingaps. Location withingap (i.e., in the rootpit,on the rootmound,on thebole,or atvarying istancesfrom he bole) had a significantffectn seedlingden-sity Table 4, Fig. 3). Tukey's a posteriorimultiplerangetest ndicatedthatsignificantly ore (P < .05)seedings were found n root pits or on root moundsthan in any other ocation. Seedling densities n rootpitsand rootmounds,however,did not differignifi-cantly rom ach otherP > .05,Tukey'smultiple angetest).Similarly, omparisons betweenseedlingdensi-ties in theother ocations withingaps and understorycontrols id not revealsignificant ifferencesP > .05).

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September 1993 MELASTOMES IN A NEOTROPICAL RAIN FOREST 17414 | Leandra dichotoma 20F Miconia multispicata

=iIn gaps=In understory 1 02-

Miconia affinis 8 Miconia nervosaF~40 I

6 r Miconia gracilis 20 Miconia simplex16FnP M B |1mjj5m|| 1Omjj~j1m

LOCATIONFIG. 3. Seedling densityof six most common melastome species in the 10 gaps and paired understoryites. Locationsare: P, rootpit; M, on rootmound; B, on rootbole; I1m , in transects+ 1 m frombole; 1 m1, n transects+ 5 m frombole; I1Om , n transects 10 m frombole. Data are means and 1 SE.

ANOVA also indicated hatvariation n seedling bun-dance amongwithin-gap itesdiffered etweenyoungerand olderalluvial soil types interaction erm n Table4). In gaps on younger lluvial soils, seedlingswere essabundant nroot pits or rootmounds relative o othersites within hesegaps. In gaps on weathered lluvium(Arboleda consociation),seedlingswere always muchmoreabundant n root pits and on root mounds.In all gap sites, ight evel (estimated as GSF) washighest top the bole, and declinedsteeply owards hegap edge (Fig. 5). Light levels atop fallentrunks nunderstory ites were lower than light evels at gapedges (Fig. 5). Because of shadingeffects y the rootmound, ight evels in the root pit were comparabletothose found between1 and 5 m away from he fallenbole (Fig. 5). There were ignificantifferencesetweenlocations withingaps (P < .001, ANOVA; Fig. 5), aswell as significant ifferencesetweengaps in all threelightmeasures P = .001, ANOVA; data not shown).Locationwithin gap was a stronger eterminant fseedling bundance than was variation n light vail-abilitywithingaps (Fig. 5). Average seedling densitywas two orders of magnitudegreaterwithinroot pitsthan n any other ocationwithingaps, although ightlevels within root pits were intermediate elative toother positions withinthe gaps (Fig. 5). ANOVA in-dicated that overall, only location within gap had a

significantffect n seedling bundance (Table 4); theaddition ofany measureof ight vailability, lobal sitefactor,direct site factor, ndirect site factor,or un-weighted penness, as a covariate n the ANOVA didnot improve the fit fthe model.SEEDLING GROWTH IN CONTROLLED

LIGHT ENVIRONMENTSMethods

Although revious field nd shade-house studies n-dicated that all melastome cuttingsresponded posi-tivelyto some increase n light vailability DenslowTABLE 3. Results ofWilcoxon's matched-pairs igned-rankstests contrasting eedlingdensities n and out of gaps forthe six most common species.

Lightrequire- Two-tailedment* Species Z-score PHigh Leandra dichotoma 3.06 .002High Miconia affinis 2.35 .019Low Miconia multispicata 4.84 .0001Low Miconia nervosa 3.35 .0008Low Miconia gracilis 1.57 .116Low Miconia simplex 2.20 .028* Lightrequirement: ow, some degree of shade tolerance;High, high-light-demanding.

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1742 AARON M. ELLISON ET AL. Ecology,Vol. 74, No. 620

|IIm In gaps_ In understory10

PI 0 MOUND PITcn-4 0. 20A

0.2

-10 -5 -1 0 +1 +5 +10DISTANCE FROM BOLE (m)

FIG. 4. Density of melastome seedlings away from thegapmakerbole and in tip-uppitsand mounds within 10gapsand paired understory ites.et al. 1990,and unpublishedmanuscript), esponsepat-terns f melastome eedlingswereundocumented.Weexamined seedling growthof eight species of mela-stome underthreedifferentontrolled ight evels inshade-houses tLa Selva (question 6,see Introduction).Newly germinated eedlings of Conostegia subcrustu-lata, Miconia affinis, . barbinervis, . longifolia,M.multispicata,M. nervosa,M. simplex and Nepseraaquaticawere ransplantednto50 x 25 x 6 cmplasticflats f heat-sterilized lluvial sand from he banks oftheRio Puerto Viejo. After wkgrowingn 20% offullsunlight, he seedings developed one pair of trueleaves and weretransplantednto flats f sterile andand alluvial soil (50:50). Clear plastic sheetingwasplaced 1m above the flats o prevent ain dropsfromuprooting seedlings. The plastic uniformly educedambient light by 5%.Twelve weeks later two pairs of true eaves, -10mmtall), ach seedlingwas transplantedntothe enterof a 300 mL, 6 cm diameter plastic cup filledwith a50:50 sand: soil mixture.This mixturewas not ster-ilized. All of thesespeciesare mycorrhizal J.S. Den-slow and A. M. Ellison, unpublishedmanuscript),ndalthoughwe did not deliberatelynfect he soil, freshTABLE 4. Results ofANOVA testing ffects f ocationwith-in gap and soil typeon seedlingdensity.

Source ss df MS F PLocation (L) 96.95 5 19.39 21.25 80% in all light evels (Table 5), exceptforM. sim-

20150.5 Root pitCQ

= 0.4

0.3 +5m+10m( 0.2 _ +mF~~~~~11

0.1- I BoleUnderstory t0.0 I I I I0.00 0.05 0.10 0.15GLOBAL SITE FACTOR

FIG. 5. Relationship between eedlingdensity nd globalsite factorGSF) at five ocations withingaps and in thead-jacent forest nderstory. alues shown are means ? 1 SE.

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September 1993 MELASTOMES IN A NEOTROPICAL RAIN FOREST 1743TABLE 6. Mass (g) at finalharvest f melastome eedlings nthethree ifferentight onditions n = sample size). IntraspecificdifferencesP < .05, Tukey's HSD test formultiple comparisons among means) across light treatments etweenfinalbiomasses are indicated by differinguperscripted etters.

Light evel (% offull unlight)Light 2% 20% 40%require- Life-ment* form* Species X ? ISE n X I1 SE n X ? 1 SE nHigh S Conostegia subcrustulata 0.017 0.009a 7 0.811+ 0.185b 7 0.889? 0.115b 6High S Miconia longifolia 10.009 + 0.00 a 20 0.105? 0.020b 19 0.109 ? 0.038b 17High H Nepsera aquatic 0.013 ? 0.002a 20 0.083 ? 0.029a 12 0.325 + 0.105b 20High S Miconia barbinerx'is 0.004? 0.0004a 6 0.061 ? 0.041a 7 0.055 ? O.0ab 7High T Miconia affinis 0.008 ? 0.00 a 18 0.031 ? 0.008a 20 0.029? 0.010ab 16Low T Miconia multispicata 0.013 ? 0.002' 16 0.082 ? 0.014b 19 0.080 ? 0.020b 20Low S Miconia nervosa 0.004 ? 0.0002a 19 0.089 ? 0.023b 18 0.028 ? 0.005a 15Low S Miconia simplex 0.003? 0.0002a 13 0.008 ? 0.002b 14 0.008 ? 0.00 lb 6* See Appendix 1 fordefinition f light equirement nd life-form.

plex,a shade-tolerant peciesof the forest nderstory,in which survivorship eclineddramaticallywith n-creasing ight evel. Survivorship f the otherspeciesdid not varywith ight evel (Table 5).All specieswere substantially eavier at harvest nthe 20% light reatment elativeto the mass of theirconspecifics rown nthe 2% light reatmentTable 6).Only the biomass of Nepsera aquatic, a high-lightspecies common to riverbanks, ncreasedfurther e-tween 20% and 40% sunlightTable 6). Harvestbio-mass of Miconia nervosawas greater t 20% light Ta-ble 6). Differencesn growth ate among species andtreatmentparallel those in final biomass (data notshown).

Leaf area and specific eafmass were oftenhigher t20% or 40% offull unlight han t the2% levelstypicalof forestunderstory, lthoughthe patternswere not

consistentwithin high-light-demandingr shade-tol-erant groups Table 7). Relative allocation to shootsand rootsdid not differ onsistentlymong ight reat-ments Table 7).

DISCUSSIONEarly ife history haracteristics, atterns fgermi-nation, establishment,nd early seedlinggrowth, if-fered among the melastomes thatwe studied. Theirseeds' responsesto passage throughbirds, ikelihoodof establishment, nd seedling growthresponses tovaryingight onditionsvaried with ife-formnd adulthabitat. n addition, suitesof these characteristics idnot co-occur nthe same combinations hathave been

found for pioneer or climax canopy tree species. Inclosing,we discuss patterns f interspecific ariationin these characters that we observed among mela-TABLE 7. Morphological characteristics t finalharvestof melastome seedlings n the threedifferentight onditions % offull sunlight). ntraspecific ifferencesP < .05, Tukey's HSD test for multiple comparisons among means) across lighttreatments etween finalbiomasses are indicatedby differinguperscriptedetters. ample sizes as in Table 6.

Specific eaf massrequire- Statis- Leaf area (cm2) (g/cm2) Root: shoot ratio g/g)ment* Species tic 2% 20% 40% 2% 20% 40% 2% 20% 40%High Conostegia subcrustulata X 6.8a 127.6b 130b 1.3a 2b 2.7c 0. 9a 1.3a 1.1a

SE 3.89 16.68 12.89 0.19 0.12 0.16 0.15 0.25 0.10High Miconia longifolia X 1.8a 23.6b 13 .9b 2.6a 2.6a 4.5b 0.5 a 0.3b 0.4ab

SE 0.31 4.42 4.27 0.11 0.09 0.46 0.03 0.03 0.05High Nepsera aquatic X 7.0a 27.3ab 60.6b 0.8a .1 a 2. lb 0.4a 0.7b 0.5a

SE 1.34 8.71 15.98 0.09 0.16 0.25 0.04 0.11 0.10High Miconia barbinervis X 0.9a 14.5a 8.5a 2.1a .9a 4 Oa 1a 0.9a 0.4a

SE 0.25 9.43 0 0.58 0.23 0 0.51 0.23 0High Miconia affnis X 1.7a 7.3b 5.9a 2.4a 2.7ab 3.7b 0.7a 0.4a 0.5aSE 0.24 1.94 1.99 0.3 0.40 0.57 0.15 0.06 0.11Low Miconia multispicata X 3.5a 20.8a 13.1l 1.9a 2.2ab 4.3b 0.7a 0.7a 0.7a

SE 0.82 4.32 3.08 0.15 0.09 0.98 0.08 0.11 0.06Low Miconia nervosa X 1.la 21.4b 7.7ab 1.6a 2.6b 3.3b 0.8a 0.7 a 0.4a

SE 0.12 5.56 1.96 0.16 0.11 0.41 0.23 0.17 0.04Low Miconia simplex X 0.4a 1.2a 0.3a 4.5a 16.8a 13.4a 0.7a 0.8a 0.6aSE 0.11 0.38 0.12 1.04 5.32 3.84 0.10 0.1 0.10

* Light requirement: ow, some degree of shade tolerance;High, high-light-demanding.

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1744 AARON M. ELLISON ET AL. Ecology,Vol. 74, No. 6stores, and speculateon the relationship f this vari-ation to plant ifeform nd adult distributionquestion7, see Introduction).

GerminationAll the melastomes examined produce very small

seeds. The germination rials n vitro ndicated somedegree of induceddormancy mong at least 18 of the22 melastomes,whose adulthabitatsrange from penpastures o forest nderstory.We base thisconclusionon these species' responsesto germination ollowingmanual extraction nd prolongedcool, dry storage.However, we have little basis for speculation aboutdormancy apacity r germination equirements nderfieldconditions.Among canopy trees, only pioneerspecies characteristic f disturbedhabitatshave beenfound to have extended dormancy Vaizquez-Ydnez1974, Moreno-Casasola 1976, Holthaijzen and Boer-boom 1982, Vdzquez-Ydnez ndOr6zco-Segovia1984,Foster1986,Nfifiez-Farfdnnd Dirzo 1988). The fourspecies that did not germinate n the in vitro trials,Clidemiadensiflora, iconia dorsiloba,M. gracilis, ndM. grayumii,re all understorypecies commoninthedense shade ofthe undisturbed orest t La Selva. Onthe basis of trials n vitro,we cannotdraw any con-clusions about dormancy n thesefour pecies.We had hypothesized that passage throughbirdswouldsignificantlynhancegerminationf peciesthathad responded poorly n the in vitro trials.This hy-pothesiswas supportedforClidemia densiflora, heonly species testedof the four hathad notgerminatedinthe nvitro rials.Mayer nd Poljakoff-Mayber1975)suggested hatpassagethrough irds and defecation fpulp-free eeds generally houldenhancegerminationoffleshy ruitedpecies. However,other tudies havesuggested hatgermination f such species should bemore variable Izhaki and Safriel 1990 and referencestherein),nd that esspredictable rasynchronous er-mination houldbe favored volutionarily e.g.,Mur-ray 1988). We examined germination esponsesafterpassage through nlyone bird, Pipra mentalis.Otherbirdsfeed on melastomefruitsDenslow et al. 1986,Levey 1988b, 1990), and resultsof identical experi-mentswithdifferentirds could yieldresultsdifferentfrom urs. In particular, ipra, like most frugivorousspecies, acksa grinding izzardthat ould abradeseedcoats. Additional experimentswithothergerminationconditionsor bird species could be used to examinecritically ur observationsthatgerminationpatternsare variable within ife-formr adult habitatamongthese melastomes.

EstablishmentEstablishment robabilitiesontheorder f1 x 1 -3forM. affinis,M. gracilis,and M. nervosa across all

habitats) were low but similar to those observed forother mall-seeded pecies,e.g., Cecropia obtusifoliatLos Tuxtlas,Mexico (Alvarez-Buyllaand Garcia-Ba-

rrios 1991), and much less than those observed forlarge-seeded species (e.g., Augspurger1984, Howe1990). Establishment f melastomeseedlings,ikeoth-er small-seededspecies,was low in forest nderstoryenvironments. n fieldexperiments, mergenceandsurvivalwere highest n the high-lightnvironmentsof treefall aps for ll speciesplanted.Naturally stab-lished melastome seedlingsalso weremore commonin gaps than n theforest nderstory.Seedlingsof sevenmelastomespecies,Clidemiadis-color,Leandra dichotoma,Miconia affinis, . gracilis,M. multispicata,M. nervosa, nd M. simplex,were allfound morecommonly n treefall aps than n nearbyunderstory. eproductivelymature ndividualsof twoof these species,C. discolor nd M. gracilis,were notrestrictedo gaps, and in factare common in the un-derstoryt La Selva (J.S. Denslow and A. M. Ellison,unpublishedmanuscript). he otherfive pecies appeartobedependent ngapsfor ruitingnd floweringLev-ey 1 88a, 1990). Species thatwerefounduncommonlyin our searchforestablishedseedlings re also foundrarely s mature dultsat La Selva (J. S. Denslow andA. M. Ellison, unpublishedmanuscript).However,seedlingsof two of these species, Conostegia setosa,Henrietteatuberculosa,were more common in gapsthan n theunderstory, hiletheresttendedto occurmore frequentlyn the understory.Field contrastsbetweengaps and understoryllus-trated pparentgap-dependenceof manymelastomesfor uccessful stablishment; hisresult s evidenceofa strongight ffect n seedlingestablishment.Withingaps, seedlingdistributionswere not relatedto esti-mated ight vailability; eedlingsweremost abundantin rootpits and on rootmoundsalthough ight vail-abilitywas significantlyower n root pitsthan n gapcenters.However,quantitativemeasuresof ightwith-ingapmicrositeswerenot related ignificantlyo seed-lingdistributionwithingaps, and higher ight evelshave been often itedas one of themain reasonsthattree seedlingsand saplingsgrowbetter n gaps (e.g.,Frankieet al. 1974, Denslow 1980, Putz 1983, Augs-purger1984, Fetcheret al. 1987). Putz (1983) foundthat pioneertree eedlings olonized pitsand moundsatBarroColorado Island,Panama. He attributedhesefindings o mproved onditionsfor ermination oundwithin hesemicrosites,ncluding heexposureofmin-eral soil. Tinyrootsof lilliputian eedlings re able toimmediately enetrate hesoil unimpededbythepres-ence of litter r a dense rootmat. However, nutrientavailability extractableP, N mineralization) s lowerin therootthrow ones of gaps at La Selva (Vitousekand Denslow 1986).Otherworkers ave describeddifferentialpecieses-tablishment esponsesto within-gapmicrositesBrat-ton 1976, NUiez-Farffinnd Dirzo 1988, Petersonetal. 1990). Both the higher ightconditions n treefallgaps and thepresenceofexposed mineralsoil appearto enhance seedling establishment n high-light-de-

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September1993 MELASTOMES IN A NEOTROPICAL RAIN FOREST 1745manding nd shade-tolerantmelastome pecies.Work-ingin temperate orests, eterson et al. (1990) foundthat pecieswithdifferentrowth orms olonized dif-ferentmicrositeswithin aps. n particular,mall-seed-ed,wind-dispersedpecies weremore common in pitsand mounds,while arge-seeded, nimal-dispersed pe-cies and species that relymore heavily on vegetativereproductionwere more common nless disturbedmi-crosites.Differentialeed rain may contribute o thispatternas well. Althoughno quantitativedata are available,seed rain may be higher n gaps than in the forestunderstory. ruitproduction n shade-tolerant s wellas high-light-demandingpecies is higher in gaps(Denslow et al. 1986, Levey 1988a, 1990). Increasedactivity f frugivorous irds and higherrates of fruitremoval (Levey 1988a, b) also may produce higherrates of seed rain. Levey (1988a, 1990) also has sug-gested hat eedsmay be disperseddifferentiallyogapedgeswhere birds perchfollowing eeding. ince rootpitsoften efine ne edgeofa gap, differentialispersalmay also contribute o thehigher ensity f seedlingsin rootthrow ones.

Seedinggrowthndifferentight nvironmentsHigher ight evelshave beencited s a primaryauseof morerapidgrowth f tree seedlings nd saplings ngaps (e.g., Frankie et al. 1974, Denslow 1980, Putz1983,Augspurger 984, Fetcher t al. 1987).Althoughthe patternsof light ntensity nd wavelengthcom-positiondiffer etweenshade-house and natural gapenvironments, ur shade-houseresults re consistentwith field experiments n some of the same species(Denslow et al. 1990). Growthresponsesvarybetweenthe two extremes lassicallydescribedforphotosyn-thetic esponses:growth atesofhigh-light-demandingspeciescontinue o increase thigh-lightevels,where-as thegrowth f hade tolerant pecies plateausat owerlight evels. Amongthe specieswe studied,both high-light-demandingN. aquatic, Co. subcrustulata) ndshade-tolerantMi. implex) xhibited he xpectedpat-terns.Between theseextremes, owever,we foundnoconsistentpatternsn seedling growth ates to distin-guish among species with differentdult habitat dis-tributions. pecies rankings ased on mass at harvestwere similar at 2% and 20% of fullsunlight.Thesegrowth atterns eflect he light nvironments ypicalofa gap-understorymosaic: deeplyshaded forest n-derstorylight evelsat 1-3% offull unlight; hazdonand Fetcher1984) punctuated yoccasional smallgaps(light evels at 10-20% of full unlight;Denslow et al.1990). Species persistingn this heterogeneous nvi-ronment mightbe expected to exhibit considerableshade toleranceas well as some plasticity f growthresponse n the presenceof the enhanced light evels

associatedwithcanopydisturbance.Similarly,comparisons of allocation patternsbe-tweenspecies within ighttreatments id not reveal

any suite of responsescommon to species frompar-ticularhabitats. For example, Conostegia subcrustu-lata, found nly n abandonedpastures nd alongroad-sides, and the shade-tolerantMiconia simplex hadsimilarbiomass allocation patterns o leaves, stems,and roots at all light evels. However, total leaf areaand specific eaf mass ofthesetwo species differedneach light nvironment. onostegiasubcrustulata adsignificantlyreater eaf area but lower specific eafmass thanM. simplex n each ofthe three ight nvi-ronments. he other ix species,adults ofwhichwerefound n habitatsranging rom bandoned pastures oforestunderstoryAppendix 1) showed more similarbiomass allocationresponsesto each other hanto ei-ther C. subcrustulata r M. simplexin each lighten-vironment.As with germination nd establishmentpatterns,herefore,atterns fearly eedlinggrowthnthese speciesdid not reflect ifferencesn adultdistri-butions. CONCLUDING REMARKS

AmongLa Selva melastomes,variation n seed ger-mination, eedlingestablishment,nd seedlingdistri-butionwas not consistent mongspeciesfrom imilarhabitats. t may notbe possible to generalizebroadlyfromregeneration ategoriesderivedfrom tudies ofcanopy trees (e.g., pioneer vs. climax: Swaine andWhitmore1988, Whitmore1989) and based on cor-related germination, stablishment nd growth har-acteristics f species fromdifferent lantfamilies cf.Martinez-Ramos et al. 1989). Our data from singleplant family uggest hatphylogeneticonstraintsm-portantlynfluenceome lifehistory raits nd that hesuitesofcharacteristicsftenused to describe ifehis-tory trategiesmay be decoupled where phylogeneticconstraintsre strong. orexample, he peciosegeneraMiconia, Clidemia, Conostegia,and Ossaea all pro-duce small,watery erries ontainingargenumbers fvery small seeds, traitsoften ascribed to pioneer orcolonizing species. Species in thesegenera,however,occur na widevariety fhabitats ncluding itesheavi-lydisturbed yhumanactivity nd intact ropicalrainforest nderstory.n additionthis tudyhas shownthatgerminationnd seedlinggrowth atesof these speciesare similar nd that ven speciescharacterized priorias highly hade tolerantappear to requiregaps anddisturbed oil forgerminationnd establishment.However,none of thespecies thatwe characterizedas high-light-demandingerefound s seedlings n ei-thergap or understorynvironmentsn the rainforestat La Selva. In a separatestudyof seed raininto fourgaps in this forestDenslow and Gomez Diaz 1990),122 seeds of20 melastome pecieswere collectedover1 yr.None of the species characterizedhere as high-light-demanding ccurredin those collections (J. S.Denslow and A. E. Gomez-Diaz, unpublisheddata).Lack of an effectiveeed rainmay thusaccountfor heabsence of seedingsof thesespecies in gaps, although

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1746 AARON M. ELLISON ET AL. Ecology,Vol. 74, No. 6our data indicate that uch seedlings hould be able tosurvive initially following germination. Low adultgrowthrates and perhaps survival in light environ-ments haracteristic fthisforest Denslow et al. 1990)apparently ccount forboth the observed distributionsof adults and the lack of seed sources forgap coloni-zation. Species lacking an appreciable level of shadetolerance s adults may be unable to surviveextendedperiodsof ime ntheforest nderstory etween anopyopening events. The combined effects f inadequateseed rain and low probability f adult survival n low-light nvironmentsmay thus producerestricted dultdistributions lthough eed and seedling raits re sim-ilar to those of more widely distributed pecies.

ACKNOWLEDGMENTSWe thank Joel Alvarado C., Guillermo ChaverriS., andElizabeth Farnsworth or assistance in the field.The Orga-nizationfor ropical Studies, nd especiallyJoseArturo e6n,and David and Deborah Clark, provided logistical supportand access to a marvelous environment n which to work.Frank Almeda, Carol Augspurger, lizabeth Farnsworth,ndDoug Levey provided valuable comments on early versionsof this paper. This work was supported by NSF BSR 86-05106, and is contribution o. 15 from he La Selva TreefallGaps Project.

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1748 AARON M. ELLISON ET AL. Ecology, Vol. 74, No. 6APPENDIX 1

Melastomataceae used in germination nd seedlinggrowth xperiments. ll collection ocations refero La Selva BiologicalStation.All collection dates are in 1988.LightSpecies Life-form* Habitatt requirement

Clidemia crenulata Gleason? S P/S LC. densifloraStandl.) Gleason? S P LC. dentata D. Don.? S S/O HC. discolor Triana) Cogn.? S S LC. apurensis DC. var. heterobasis DC.) Wurdack? S R/Sw LConostegia subcrustulata Beurl.) Triana S 0 HLeandra consimilisGleason? S P/S LL. dichotomy D. Don.) Cogn.? S S/O HL. mexicana (Naud.) Cogn.? S S/O HMiconia affinis C. T S/O HM. barbinervisBenth.) Triana S 0 HM. centrodesmaNaud.? S/T P LM. dorsiloba Gleason? T P LM. gracilisTriana? S P LM. grayumiiAlmeda? S P LM. longifolia Aubl.) DC. S 0 HM. multispicataNaud. T S LM. nervosa J.E. Smith) Triana S P/S LM. simplex Triana S P LNepsera aquatic (Aubl.) Naud. H R/Sw HOssaea macrophylla Benth.) Cogn.? S P/S L0. micrantha Sw.) Macf. ex Cogn.? T P/S L* Life-forms: , herb; S, shrub multiple runks,ittle econdarywood on main stem);T, tree single runk,muchsecondarywood on main stem).t Habitatwherecollected:P, primary orest; , secondaryforest; , abandoned pasture;R, riverbanks; Sw, swamps.t Light requirement: , some degreeof shade tolerance;H, high-light-demanding.? Used in germination tudyonly.

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September 1993 MELASTOMES IN A NEOTROPICAL RAIN FOREST 1749APPENDIX 2

Description of sites sampled forMelastomataceae seedlings.The location given s thenearest rail, he distance alongthattrail, nd the direction degreesE of magneticN) from he trail. The orientation fthe fallenbole is given as degreesE ofmagneticN.Location Approxi-______ ______ ______ O rienta- m te SoilSite Bole species Trail (m) 0E tion 0E) age (mo) consociation*1 Gap Cespedesia macrophylla eem. CCC 575, 1600 2250 24 Arboleda(Ochnaceae)Understory Pentaclethramacroloba Willd.) 0. CCC 550, 1400 2600 ArboledaKtze (Mimosaceae)

2 Gap P. macroloba CCC 650, 3050 3000 12 ArboledaUnderstory P. macroloba CCC 620, 3250 3250 ... Arboleda3 Gap unidentified CCC 685, 1400 1400 30 ArboledaUnderstory P. macroloba CCC 720, 1400 2000 Arboleda4 Gap P. macroloba SSO 150, 800 2290 18 ArboledaUnderstory P. macroloba SSO 150, 800 3300 Arboleda5 Gap Pterocarpus ohriiVahl SURA 250, 2400 1550 7 La Selva(Papilionaceae)

Understory Dipteryx anamensis (Pittier)Record SURA 200, 1540 1540 La Selva(Papilionaceae)6 Gap Pentaclethramacroloba CEN 640, 1300 3050 3 ChancheraUnderstory P. macroloba CEN 650, 3400 1610 Chanchera7 Gap Hymenolobiummesoamericanum CEN 690, 2480 2010 27 ChancheraLima (Papilionaceae)Understory P. macroloba CEN 700, 600 1390 Chanchera8 Gap P. macroloba SSO 750, 1400 2300 24 ArboledaUnderstory P. macroloba SSO 760, 1400 2200 Arboleda9 Gap Dussia macroprophyllataDonn. Sm.) CCL 200, 2400 1700 21 HoldridgeHarms (Papilionacae)Understory P. macroloba CCL 270, 1300 1650 ... Holdridge

10 Gap Inga sp. (Mimosaceae) CCL 650, 2920 2510 10 HoldridgeUnderstory P. macroloba CCL 725, 1680 3100 ... Holdridge* Soil taxonomyfollows Sancho and Mata (1987) and Sollins et al. (in press).The Arboleda consociation s a weatheredalluvial soil, the Chanchera and La Selva consociationsare alluvial soils from he middle trace of the Rio Sarapiqui, and theHoldridgeconsociation s an alluvial soil from he middle terrace ftheRio PuertoViejo.