Caldasia 23(1): 203-212

DIVERSITY AND HABITAT DIFFERENTIATION OFMOSSES AND LIVERWORTS IN THE CLOUD FOREST

OF MONTEVERDE, COSTA RICAS. ROB GRADSTEIN

Institute of Plant Sciences, University of Gottingen, Untere Karspüle 2, 37085 Gottingen,Germany

DANAGRIFFIN IIIFlorida State Museum, University ofFlorida, Gainesville, Florida 3261 1, US.A.

MARIA ISABELMORALES

Escuela de Bíologia, Universidad de Costa Rica, San José, Costa Rica

NALINI M. NADKARNI

The Evergreen State College, Olympia, WA 98505, U S.A.

ABSTRACTAn inventory ofthe understory and canopy of 4 ha oflower montane cloud forest atMonteverde, Costa Rica, yielded 190 bryophyte species: 133 hepatics, 56 mossesand 1homwort. Thick branches ofthe lower canopy were by far the richest habitat interms of number of species (99), trunks from 1m upwards had 65 species, lianas,shrubs, saplings, or living leaves in the understory had about 36-46 species each, and16 species were found on rotten logs. The figures are illustrative of the greatdiversification of microhabitats of bryophytes in a tropical montane cloud forest.About 36% ofthe species, including more than half ofthe corticolous ones, occurredexclusively in the canopy. It appeared thatthe percentage ofbryophyte species restrictedto the canopy may be the same in lowland and montane rain forests, in spite ofthegreat differences in species abundance and composition in the two kinds of forest.

Key words. Bryophytes, Cloud forest, Biodiversity, Costa Rica.

RESUMEN

Ciento noventa especies de briofitas (133 hepáticas, 56 musgos, 1antocerote) fueronencontradas en un inventario hecho en 4 hectáreas del sotobosque y el dosel en elbosque nublado (1500 m) de Monteverde, Costa Rica. Las ramas gruesas del doselfueron la porción más rica en termino de numero de especies (99), en troncos había65 especies, lianas, arbustos, árboles juveniles o hojas vivas en el sotobosque teníanentre 36-46 especies cada una, y 16 especies fueron encontradas en troncos en des-composición. Las cifras ilustran la gran diversidad de microhabitats de briofitas en elbosque nublado. Cerca de 36% de las especies, incluyendo mas de la mitad de loscorticolos, se presentaron exclusivamente en el dosel. Parece que el porcentaje deespecies de briofitas restringidas al dosel podría ser el mismo en bosques de tierrasbajas y en bosques nublados, a pesar de la gran diferencia en abundancia y composi-ción taxonómica de las briofitas en las dos clases de bosque.

Palabras clave. Briofitas, Bosque nublado, Biodiversidad, Costa Rica.

Diversity and habitat differentiation of mosscs

INTRODUCfION

Tropical rain forests, including montane cloudforests, harbour a large diversity ofbryophytes,probably due to the great variety ofmicrohabitats in these forests. Ofan estimated4000 species (2650 mosses, 1350 hepatics)occurring in tropical America, about 80% ofthe hepatics and 50 % of the mosses areconfined to these forests (Gradstein et al., inpress). Most ofthe bryophytes in tropical rainforest are epiphytes and their abundance variesconsiderably with elevation. In lowland rainforests, below 500 m, bryophyte cover is poorand mostly restricted to the canopy. In montan erain forests, especially in the very moist cloudforests, growth of epiphytic bryophytes isusually much more luxuriant. Moreover, theforest floor may be covered with densebryophyte carpets. The lowertemperatures andhigher light levels in the cloud forest and theavailabiIityof plentifu1water due to impact of fogfavour the accumulation of dead organic mate-rial on the ground and the abundant growth ofthe epiphytic and terrestrial bryophytes(Richards, 1984;Gradstein & Pócs, 1989).Our understanding ofbryophyte diversity oftropical rain forests is still fragmentary. Com-plete inventories are very scarce. Most studiesonly deal with part of the flora, leaving"difficult" groups such as the tiny Lejeunea-ceae (Hepaticae) unidentified. Moreover,attention is usually restricted to the lower partofthe forest, whilst the higher portions ofthetrunks and the canopy branches are neglecteddue to their inaccessibility (Wolf, 1993).Cornelissen and Gradstein (1990) found thatin lowland rain forest ofGuyana about 50 %ofthe bryophyte species occurred only in thetree crowns and on the upper portions of thetrunks, over 10m aboye ground level. Incontrast, only 14 % of the species wereexclusive to the understory. The number ofspecies restricted to the canopy in cloudforests is still unknown. Another importantfinding of recent work is that species density

204

of epiphytic bryophytes in rain forests is highand minimum areas for sampling thereforerelatively small. Complete sampling of 4-5 trees(from base to outer canopy) may yield over75% of the flora of a homogeneous foreststand (Cornelissen & ter Steege, 1989; Wolf,1993; Gradstein et al., 1996). Costa Rica'sMonteverde Cloud Forest Reserve is one thebest studied montane moist forests wor1d-wide. Monteverde: Ecology andConserva/ion of a Tropical Cloud Forest(Nadkarni & Wheelwright, 1999) incorporatescontributions of 140 authors and over 1800references. Vascular epipyhtes have be enstudied in detail by Nadkarni and associates(e.g., Nadkarni, 1986; Nadkarni & Matelson,1992; Ingram & Nadkarni, 1993). In contrast,very little work has been done on thebryophytes ofMonteverde. Reed & Robiríson(1971) published a first list of 164 species (90mosses, 73 hepatics, 1 hornwort) based onrandom collecting in the forests and in pastureareas. Additional species were reported byGradstein et al. (1994) and Sillet et al. (1995).The latter authors analysed the epiphyticbryophyte flora in the canopy of six Ficustuerckheimii trees, three in the dense primaryforest and three isolated ones in adjacentpasture land, and could demonstrate that thetwo sets of trees had very different speciesassemblages.This paper deals with the bryophyte diversityin the cloud forest ofMonteverde. The mainpurpose of this study was to described thecomposition and habitat differentiation oftheflora and to determine floristic differencesbetween the canopy and understory of theforest.

MATERIAL AND METHODS

We conducted an inventory of bryophyteswithin a 4 ha study site, consisting of tourplots of one hectare each, in MonteverdeCloud Forest Reserve during November 1992and January 1994. The Monteverde Cloud

Forest Reserve is situated in northcentralCosta Rica (10° 18'N, 84°48'W) along the crestofthe continental divide in the Cordillera deTilarán. The forest is subject to cloud-bearingtrade winds that move across the Cordillerafrom the northeast. The trade winds occurthroughout the year, but most frequentlydeliver mist between Novernber and May.Total annual annual rainfall is 2000-2500 mm,most of which falls during May to October,but fog and mist rnay contribute an additional500-2000 mm ofannual precipitation (Ingrarn& Nadkarni, 1993).The 4 ha study site is in the lower montanerain forest (1550 m elevation) about 1 kmsouthwcst ofthe headquarters ofthe reserve,on the leeward, Pacific side ofthe Cordillera.The primary forest is 20-30 m high with a fewcrriérgents to 35 m tall. Ocotea tonduzii(Lauraceae), Ficus tuerckheimii (Moraceae)and Meliosma ideapoda (Sabiaceae) are theprincipal canopy tree species, making up ca.40% oftotal basal area oftrees.About 350 collections of bryophytes weregathered randomly in the four hectare plots.An average of2-3 trees per plot were climbedand samples were taken from branches ofthelower canopy. Sampling of the outer canopywas done from recently fallen trees. In general,canopy sampling was less detailed than theinventory of the understory, however. Thecollections were deposited in FLAS, U and USJ.

RESULTS AND D1SCUSSION

1 . Distribution ofspecies in the cloudforest.Bryophytes were abundant on treelets, shrubs,lianas and rather exposed trunks in the forestunderstory and, particularly, on thick branchesofthe inner forest canopy. On trunks in deepshade, bryophytc cover was usually ratherscanty. Hcpatics were more abundant thanmosses, both in tcrms of biomass and innumbcr of species.

Understory. Thc bryophyte flora oftheforest undcrstory was very different from that

S. Rob Gradstein el al.

ofthe canopy. The most frequent bryophyteson trunks, shrubs, lianas etc. in the understorywere Plagiochila spp.; Por otr ich umkorthalsianum and Radula antillana. Othercommon taxa included Metzgeria leptoneura,Lepidopilum mueller i, Omp hal ant h usfiliformis, Taxilejeunea pterigonia andTrichocolea tomentosa. In well-lit sites thependent mosses Phyllogonium fulgens andvarious Meteroriaceae were frequently seentogether with the robust hepatics Porel!aswartziana, Bryopteris filicina, Radulagottscheana and Plagiochila spp.

On trunk bases Cephalozia crassifolia,Fissidens spp., Hookeriopsis falcata,Hypopterygium tamariscimum, Lophocoleaconnata, Telaranea nematodes and variousunidentified species of Lejeunea were quitecommon. Other taxa characteristic of thishabitat included Calypogeia spp., Pallavicinialye/lii, Cyrtohypnum schistocalyx (= Thuidiumschistocalyx), Leskeodon andicola,Octoblepharum erectifolium and Syrrhopodonspp. Species of Bazzania occurred here andthere on trunk bases but were much morecommon in the forest canopy.

The forest floor had much rottenwood (Iogs, fallen branches) and this was alsoan important habitat for bryophytes, e.g., thethalloid hepatics Monoclea gottschei andRiccardia spp. and the mosses Hookeriopsisfa/cata, Mittenoth amnium reptans,Pl agiom nium rhynchophorum andPyrrhobryum spiniforme. The single hornwortencountered in the study site, Megacerosvincentianus, was also a species of rottenlogs. The majority of the species of rottenlogs al so occurred on the trunk bases,especially on rotten, humose ones.

Canopy. The lower, ± horizontal branchcsof the canopy were thickly covered bybryophyte mats. Species o f Bazzania,l.epidozia, Macromitrium, Plagiochila,Herbertus and Frullania convoluta were themost prominent elements. Macromitrium andHerbertus were restricted to the canopy but

205

Diversity and habitat differentiation of mosses

species of Bazzania and Lepidozia alsooccurred lower down in the understory. Plantsof Frullania convoluta fallen from thecanopy sometimes continued growth onbranches in the understory.

Other bryophytes characteristic of thickcanopy branches and lacking in theunderstory included the hepatic generaFrullania, Adelanthus and Ceratolejeunea(the latter sometimes forming extensive darkmats), furthermore Kurzia capillaris,Leptoscyphus porphyrius, Syzygiellapectiniformis, Tylimanthus laxus, and themosses Acroporium pungens, Bryumcapillare, Campylopus arctocarpus,Leucobryum giganteum, Leucolomacruegerianum, Pilotrichella flexilis,Squamidium nigricans, and Syrrhopodonlycopodiodes. Light-green mats of Papillariaimponderosa and the pendent Phyllogoniumsand Omphalanthus filiformis were commonboth in the canopy and in the understory,behaving as ecological "generalists".

Fine twigs ofthe outer canopy harboureda rich ramicolous bryophyte communitycharacterized by Daltonia gracilis and manysmall species of Lejeuneaceae. Sorne ofthesealso grew on living leaves. Foliicolousbryophytes, most ofthem Lejeuneaceae, wereabundant especially in the forest understory.

200

The most common ones included Odonto-lejeunea lunulata and species ofCyclolejeunea (e. convexistipa, e. peruviana),Drepano-lejeunea and Aphanolejeunea.

2. Species richness. Our inventory yielded 190bryophyte species (Table 1): 133 hepatics, 56mosses, and 1 hornwort (Megacerosvincentianus). The average number perhectare was 88 species, with highest numberin plot 2 (118) and lowest number in plot 4(74). In comparison, a very detailed analysisofthe canopy by Sillet et al (1995) found 109bryophyte species on three Ficustuerckheimii trees in the Monteverde cloudforest. This suggests that our canopy specieslist is still incomplete.

Species-area curves showed that one plotyielded 45 % oftotal diversity, and two plotsyielded 75% (Fig. 1). In comparison, whenbryophyte diversity on trees only is studied(excluding shrubs, logs etc.), the 75% level isusually obtained by analysis ofjust four trees(Wolf, 1993).

The absolute dominance ofhepatics overmosses at the study site in terms of speciesnumber is characteristic ofthese neotropicalmoist forests. In palaeotropical forest, mossestend to be more abundant (Gradstein & Pócs,1989). Plagiochila was by far the most

Total

Hepancs

0-" ..,..... ······0, .-..... " ... ···0.".-... Mosses.

1 2 3 4

Plot Number

Fíg. 1, Species-plot relationships.

206

speciose genus (18 spp.), followed by thehepatic genera Lejeunea and Bazzania (7 spp.each), and Frullania and Radula (6 spp.).Among the mosses, Lepidopilum andMacromitrium (4 spp.) were the most speciosegenera, the former mainly in the understory,the latter very abundant in the canopy.

3. Habitat diversification. The distribution ofthe species of the species over the variousmicrohabitats is shown in Fig. 2. Thickbranches ofthe lower canopy were by far therichest habitat for bryophytes and yieldedabout 100 species. Trunks (from l m upwards)had 65 species, living leaves 46 species andtrunk bases 36 species. Fourty species werefound on lianas, poles and small branches onshrubs, sapling etc. in the forest understory.The lowest number ofspecies (17) was foundon rotten logs; however, half of these wereexclusive to rotten logs and not foundclsewhere. A similarpercentage was obtainedfor epiphylls: about half of the foliicolousspecics (23) were only found on living leaves,others occurred also on other substrates. The

120

99100

80<f)

".(3":F"O 60Q;.oE:JZ

40

20

OBr Fa La Sh

s. Rob Gradstein el al.

figures are illustrative of the greatdiversification ofmicrohabitats ofbryophytesin a tropical montane forest.

Species richness in the canopy comparedto the understory was 117 vs. 121. Of these,48 (25%) occurred both in the canopy and theunderstory, 38% were exclusive to theunderstory, and 36% to the canopy (Fig. 3A).

200

Canopy

011lE::JZ

Canopy &Understory

Understory

A B

Fig. 3. Comparison of bryophyte speciesrichness in understory and canopy. A. Totalspecies diversity. B. Corticolous speciesdiversity (species ofrotten logs and epiphyllsexcluded).

65

Tr Trb TwFig. 2. Distribution ofbryophyte species over different microhabitats. For abbreviations see

Table 1.

207

Diversity and habitat diffcrcntiarion of mosses

Table 1. Bryophyte species collected in the 4 ha study site (hectare plots 1-4) in the MonteverdeCloud Forest Reserve.

PLOT CANOI'Y lINDERSTORY

AphanolcjcuneaEvans;\, gracilis Iov-Ast

exigua 2,4 Fu

Fo

I'LOT CANOI'\' UNIlERSTOR\'

C. luteola (Sprucc) Grollee peruviana (Lehm & 1,2,3, Fo, "\'1Lindcnb.] EvansDicranolejeunea axillaris Tw(Necs & Mont.) SchiffnDiplasiolcjcunea alata Jov.. Tw

AstD. brunnca StcphD. cavifolia Steph 2, 3[) johnsonii Evans 1,4D, montccristcnsis Winkler 3

f) inchoata (Mcissn.) Evans 1,2,3 Br. Tw

A subdiaphanacristulata (Schust.) Pócs

var 1,2,3,4

1,2,3,4

TwBr

r-,

Tw

Fo

ro

Fo

III

Lo, Sh, Tr, TrbTwBI TITw

Fu

Fo

Sil, TI

Fo

ro

Fo

Fo

Foro

FoFuroro

ro

ro

Fo

lIl:PATICAEAcroholbaccaeTylimanthus laxus Spruce 1, 2,4 !lrAdclunthuceaeAdclanthus carabayensis [lr(Mone) GrollcA. dccipicns (Hook.) J'ditt. BrA. pittieri (Stcph.} Gro!le [lr

AncuraccacRiccardia fucoidca (Sw) Br LoSchitTnR. sp 1, 2,3, Br Lo

CulypogcinceaeCa!ypogeia crcnulata TrbIjischler

e peruvtana (Nees & TrbMont.) Steph

e rhombifol¡a (Spruce) TrbStepbe rhynchophy!la (Herz) TrbBischlcrCephnlozinceaeCcphalozia crnssifolia 1, 2,3, [lr Lo, Sh, Trb(Lindcnb. & GnU.) rorrOdontoschisma longiflorum Br(Tayll StephGeecalycaccneLeptoscyphus porphyrius Br(Nees) Gro!leLophocolea connata (Sw) 1, 2,3, Lo. TrbNccsL. muricata (Lehm.) Nees o 3,4 Fo, Sh, r., TrbL. trapezoidea Mont. [lrHerbertncencl lerbcrtus Jivergcns Stcph B,

11 junipcroideus (Sw) n-Gro!leH. pcnsjlis Tayl 1, 2, [l,

JubnlaceaeFrullania arccac (Spreng.) B,(iottF. brasíliensís Raddi 2,4 !lr

convoiuta Lindenb & 1, 2,3, [lr Sh (fa!len IromHampe canopy''}F. exilis Tayl 1, 2,4 Ur, TwF. laxiflora Spruce [lrr riojaueirensis (Raddi) BrAongstrJubula bogotcnsis Gntt Tr.J ungermnnniaceaeSyzygiella pcctiniformis BrSprucc (del. Vána]LejcuneaccaeAnoplolejeunea conforta n-(Mcissn.} Schiffu

'onventions~r = thick, ± horizontal branches of thc inncr forest

canopy-o = living leaves (foliicolous)00 = rotten logs

Brachiolejeunea laxifolia Tw(Tayl) SchitTn.13ryoptens filicina (Sw) 1, 2,4 n-NcesCeratolejeunea comuta Br(Lindenb.) Steph.C. marítima (Sprucc) Steph 1, 2,4 [lrC. sp 1, BrChcilolcjeunea rigjdula 1,2 Br(Mont.) SchustCololcjcunea el' standlcyi 1, 2,3,HcrzColma ulc¡ Jov.-Ast TwCyclolcjeunea(Goü.) EvansC. convcxistipa (Lchrn. & 1,2,3,Lindcnb.) Evans

acccdens 2, J,

D. pellucida (Mcissn ex 1, 2, 3,Sprcng.) SehiffnDrepanolcjcuncacampanulata (Sprucc} Stcph

D lichcnicola (Sprucc)StephEchinocolea dilatata (Evans} 3,4Schustllarpalejeunea aspera Grolle

11 oxyphylla (Nees &Mont.) StephLcjcunenSpruccL. controvcrsa Gott 1,2,4L. aff filipes Sprucc 1,2L. nava (Sw.) Nccs !, 2L. phyllobola Nccs & Mont

cephalandra

Sh = lianas, poles and small branchcs (ofshrubs, trcclct:and saplings) in the forest understory

Tr = trce trunks (frorn 1 m upwards )Trb = bases of tree trunks (0-1 111) and rootsTw = twigs olthe outcr Iorest canopy

208

Cont. Table 1

L (subgen 2,3 Sil, Trb

"LOT CANOPY UNDERSTORY

Otigcniolejeunea) spL,sp,A 2,L. sp I3 1,3Lcpidolejeunca involuta l , 2(Gutt.) Gra[[eLeptolejeunea elfiptica 2,3(Lclun. & Liudcnb ) Schiffn

L. scrratifofia Schiffll 1,2Macrolcjcunca(Steph. ) IIcrzMarchesinia robusta (Mitt.)SchiffnMicrclejeunea acutifoliaStcph\1 bullata (Tayl ) Evans:-'1 stncta (Gott el al.)Steph

luncifolia 1, 2, 3,

Neurclejeunea(Gntt.) EvansOdontolcjcuneadcccmdcntata

breuteli¡

(Sprucc)Stcpb.O lunulata (Wcb.) Schiffn 1,2,3,

4Omphalanthus(Sw.} Nceso. grandistipulus Steph 2, 4O. ovalis (Lindenb. & Gott.) 1,2,4

fiJiformis 1,2, J,

Gratis!Prionolejeunea schlimiana 1,(Gon.) Stcph. (det. Gral1e)P. spRectulejeunea berteroana 2,3,4(Gott.) EvansStictolejeunea squamata(Willd. ex Wcb.} SchiffnSymbiezidium transversal e(Sw.) Trevishookerianum (Gott et al.)Gradst. & van BeekTaxilejeunca sulphurea(Lehm. & Lindenb.) Schiffn

T ptcngomn (Lehm & 2,3,4Lindcnb.) SchiffnT spLepidoziaceaeBazzania affinis (Lindenb. & 1,2,3,Gott) Trcvis13 brcutcliana (Lindcnb &Gott.) TrevisI3 denticulata (Lindenh &GoU.) Trevis.O grncilis (Hampe & Gott.) 1,4StephI3 hookeri (Lindenb) 2, .1,

Trevis8. langa (Nees) TrevisB. stolonifera (Sw.) TrevisKurzia capúlaris (Sw.)GrolleLcpidozia armata StephL. cupressina (Sw.) Lindenb 1, 2

L. squarrosa Stcph

1,2,31,4

2, :;

1,

1,2

n-

!l,

Tw

n-

Fo, Tw

I3r, Tw

!l,!lr

Tw

!lr

!lr

n-

!lr

Br

Br

[lr

Br, TrBrn-

[lrBr, Tr

!lr

Trb (tare)

ShTr, TrhFo, Tr

Fo

FoFo, Sh

Fo

FoFo

Fo

Fo

Fo, Sil

r», Sh

Fa, Sh

Fo, ShFo

Fo

Fo, Sh

Sil

Lo

r., Trh

Trb

Trb

Tr

Fo

TRb

Telaranea nematodes (Gott 1,2,3,ex Aust.) HoweMetzgerfaccaeMetzgeria albinea SpruceMctzgeria decipiens (Mass.) 1,2,3,Schiffn.M. leptoneura Spruce 2,3,4M. liebmanniana Lindenb &GattMonocleaceneMonoclea gottschei Lindb. 1,2,3,

PullnviciuincenePallavicinia lyel1ii Hook. 1,2Symphyogyna hrogniartiiMontPlagiochilacenePlagiochila adiantoides 2,3,4(Sw) LindenbP. acrea Tayl 1,2,4P. breute1iana Lindenb

P. crispabilis Lindenb.P. cristata (Sw.) Lindenb. 1,4P diversifolia Lindenb. & 2, 3

GottP. gymnocalycina (Lchm &Lindenb.) MontP laxa Lehm. & Lindenb 1,2,3P. martiana Nees

miqueliana Lehm. & 2,4Lindcnb.P raddiana Lindenb r-guilleminiana Nees &Mont.)

P. rudischustcri RobinsP stolonifera Lindenb &Gott.P. stricta LindenbP. subplana LindenbP. tenuis LindenhP sp. Ap sp. IlPorellaceaeParella swartziana (Web.) 1,2,3,

S. Rob Gradstein el al.

1,2,3,

1,21,2

2,3,41,21,2

Br

Tw

!lr

!lr

Br

!lr

Br

Br

Br

Br

Br

BrBrTwBrBr

!lrTrevisRndulnceaeRadula antilleana Castle 1,2,3, Br, Tr

PLOT CANOPY UNDERSTORY

R. frondescens Steph. 1,2,3, Br, Tr4

R. gottscheana Tayl 1,2,4 TrR. jnvanica Gatt (= Rmacrostachya Lindcnb &Gott.)

R. stcnocalyx MontR. tenera Mitt. ex Steph. BrScapaninceaeScapania portoricensis Gott

TrichocoleaceaeTrichocolea flaccida(Spruce) Jack & StephTrichocolea tomentosa (Sw) 1, 2, 3,Gott 4

Br (rare)

!lr

Lo, Trb

Fo, Sh, Tr

Lo, Trb

Sil, Tr, TrbSil

Tw, Sil (rare)

Sil

TrbLo

Sil

Trb

Sil

Sil, Tr

Sil

Tr

Sh

Trb

Sh, Tr

Sh, TI

Sh, Tr

Sh, TrTr

Fo

Fo

Sil, Tr

209

Cont. Table 1

Diversity and habitat differentiation of mosses

PLOT CANOPY UNDERSTORY

ANTHOCEROTAEAnthucerotneeaeMegaceros vincentianus(Lehm. & Lindenb.) Steph.

MUSCIBarrramiaceaeLeiomela bartramioides(Hook.) ParBrnchytheciaceneRhynchostegium serrulatum(Hedw.) Jaeg.BrynceaeBryum cepillare Hedw.Ortbodontium pellucens(Hook.) B.S.GCnlympernceaeSyrrhopodon incompletus 1,2,3,Schwaegr. var. berteroanus(Brid.) ReeseS Iycopodioides (Brid.)CMS. prolifer Schwaegr. vartenuifolius (Sull.) ReeseDicranaceaeCampylopus(Hornsch.) Mitt

arctocarpus

Holomitrium arboreum Mitt.

Tr

Br

BrBr, Tr

Br (rare) Trb

Br

Trb

Br

Br

Leucoloma cruegerianum 1,2,3 Br, Tw(CM) JaegL. serrulntum Brid SbFissidentaceaeFissidens elegans Brid TrbF. minutus Thwaites TrbF. steerei Grout TrblIookeriaceae s.l.Callicostella pallida 1,2 Lo(Hornsch.) AongstrCrossomitrium patrisiae 2,3 Fo(Brid) C MDa\tonia gracilis M¡u TwHookenopsis falcala (Hook.) 1,2,3, Lo, TrbJaeg 4Hypnella cymbifolia 1,2,3, Trb(Hampe ) Jaeg 4H. diversifofia (Mitt.) Jaeg BrLepidopilum falcatulum SilCML muelleri (Hampe) Mitt 1,2,3, Fa, Sh

4L scabrisetum (Schwaegr.) BrSteereLeskeodon andicola (Mitt.) 1,3 TrbBrothL cubcnsis (Mitt.) Thér FoRhynchostcgiopsis flexuosa Lo(Sull.) CM.lIypnaceaeEctropothecium Brleptochaeton (Schwaegr.)BuckMittenotharnniurn reptans 1,4 Br Lo(Hedw.) Card.H ypopterygtaceaeHypopterygium 2,3 Trbtamariscimum (Hedw.) Brid

Lo

ConventionsBr = thick, ± horizontal branches of the inner forest

canopy

210

Br

Sb

PLOT CANOPY UNDERSTORY

Trb

LeucobryaceaeLeucobryum crispum C.ML. giganteum C.M 1,2 BrOctoblepharum erectifoliumMittMeteoriaceaeMeteoridium remotifolium 2,3 Br(CM.) ManuelPapillaria imponderosa 2, ] Br, Tw(Tayl.) BrotbPilotrichclla flcxilis (Hedw.) Br, TwAongstrp pentasticha (Ilrid) Wijk& Marg.Squamidium nigricans Br(Hook) BrothMniaceaePlagiomnium 2, ]rhynchophorum (lIook.) TKopNeckeraceaeIscdrepanium(Wils) BrittNeckeropsis disticha(Hcdw.) RcichardtPorotrichum korthalsianum 1,2,3,(Dozy & Molk) Mitt 4P. longirostre (Book.) Mitt. 2,3

Icntulum 1,4

mutabilePorotrichumHampeOrthotrichaceaeMacromitrium cirrosum(Hedw) BridM mamillosum Bartr..M cf. parvirete BartrM. cf. tonduzii Ren. & Card 1,2

PhyllogoniacenePhyllogonium fulgens 2,3,4(Hedw) BridP viscosurn (P Beauv.] 1,2,3Mítt.PrionodontaceaeP. fusco-Iutescens HampeP. luteo-virens (Tay!.) Mitt

RhizogoniaceaePyrrhobryum spiniforme 1,(Hedw.)MittRhizogonium líndigíí 1,(Hampe) MíttSematophyllaceaeAcroporium(Hedw.) Broth.Thuidiaceae

pungens

Cyrtohypnum schistocalyx 2, 3, 4(CM) Buck & CrumThuidium antillarum Besch

Trb

Sil

Sh, Tr

Tr

Lo

Sil

Trb

Sh, Tr, Trb

Br

Br

BrBrBr

Br Sil (inel var. gracilc)

Br Sil

BrSil

Br Lo

Br(rare) Trb

Br

Lo, Trb

Br

Fo = living Icaves (foliicolous)Lo = rotten logsSh = lianas, poJes and small branches (ofshrubs, treelets

and saplings) in the forest understoryTr = tree trunks (from I m upwards )Trb = bases of tree trunks (0-1 m) and rootsTw = twigs of the outer forest canopy

In a lowland rain forest ofGuyana, Cornelissenand Gradstein (1990) found that about 50% ofthe bryophyte species were restricted to thecanopyand 14% to the understory. The latterfigures, however, were restricted to corticolousspecies and did not include species of rottenlogs and living leaves. When calculations forthe Monteverde study site are restricted tocorticolous taxa, 52% of the species areexclusive to the canopy and 20% to the forestunderstory (Fig. 3B). It thus appears that thepercentage of species restricted to the canopymay be the same in low land and montane rainforests, in spite of the great differences inspecies abundance and composition in the twokinds offorest (see also Gradstein, 1995).

4. Floristics. At least 19 species appeared tobe previously unreported from Costa Rica(Gradstein et al., 1994): the hepaticsAdelanthus carabayensis, Bazzania affinis,Calypogeia crenulata, C. rhombifolia, Caluraulei, Cyclolejeunea accedens, Frullania exilis,F. laxiflora, Kurzia capillaris, Lophocoleacon nata, Marchesinia robusta, Metzgeriaalbinea, M. decipiens, Plagiochilarudischusteri, Prionolejeunea schlimiana,Radula antillana, R. frondescens, R. tenera,and Syzygiella pectiniformis. Three ofthese,Bazzania ajjinis, Lophocolea connata andRadula antillana, were surprisingly commonin the forest. Among the mosses and hornworts,none were new to the country.

The list includes several rare bryophytespecies, known otherwise from only very fewlocalities. Plagiochila rudischusteri is knownfrom a few localities in northern Venezuela,Panama and Pacific Colombia, Syzygiellapectiniformis is arare northern Andeanspecies, and Calypogeia rhynchophylla isendemic to Costa Rican cloud forests withthree known localities on the mainland andoccurring also on Cocos Island, where it is verycommon (Dauphin, 1999). The rare endemicNowellia reedii Robins., described fromMonteverde (exact locality unknown) and not

S. Rob Gradstein el al.

recorded anywhere else, was not found duringthis study.

ACKNOWLEDGMENTS

We are very grateful to Gregorio Dauphin forinventorying epiphylls, Stephen Ingram foradditional species records, Ricardo Solano forlogistical support, Riclef Grolle, AndreaLücking, Elena Reiner-Drehwald, Jiri Vánaand K.Yamada for help with identification, andFrans van Dunné and Ingo Holz for preparingthe figures. Fieldwork in Costa Rica by thefirst author was supported by the NetherlandsFoundation for Tropical Research (WOTRO)and the National Geographic Society (grant toNalini Nadkarni).

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