Plant species endemism in savanna vegetation on table
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Vegetatio 113: 125-139, 1994. (~) 1994 Kluwer Academic Publishers. Printedin Belgium. 125 Plant species endemism in savanna vegetation on table mountains (Campo Rupestre) in Brazil R. J. V. A l v e s I & J. K o l b e k 2 1R. Marquesa de Santos 22/1004, 22240 Rio de Janeiro, RJ, Brazil 2Institute of Botany, Dept. of Geobotany, Academy of Sciences of the Czech Republic, 252 43 Pr~honice, Czech Republic Accepted 1.11.1993 Key words: Brazil, Campo rupestre, Endemic species Abstract A new theory about the origin of endemism in the campo rupestre vegetation type is proposed and discussed, based on the studies of endemic species which have been conducted in several campo rupestre areas. Data on endemic plant species of the studied mountain ranges are provided. New localities are reported for some rare and endemic plants of Minas Gerais, Brazil. The present knowledge of their distribution is briefly discussed. Vegetation characteristics were studied in their stands by means of vegetation relevds, and a synthetic constancy table is provided. The main phytogeographical characteristics of the studied sites are given. Introduction and site characteristics Isolated table mountains in the tropics biogeographically represent isolated islands and frequently bear vegetation rich in endemic species. For example in Africa these are called 'Bowals', in the equatorial region of South America 'Tepuis' or 'Sabanas' and in central Brazil they are known as 'Campos rupestres'. In the broad sense this vegetation is a type of savanna. Various classifications of savannas were discussed in great detail by Donselaar (1965), while subsequent authors have only treated the definitions superficially. In broad terms the vegetation treated herein can be described as the 'Taffelberg type savannas' as defined by that author. During the phytocoenological survey of the vegetation of some campo rupestre communities of Minas Gerais, Brazil in 1989 (Alves 1992a; Alves & Kolbek 1993), some rare and endemic species were collected (Alves 1991). Their finding relevantly expands the present knowledge of their distribution. While some species were known from only the type localities (Smith & Ayensu 1976), others are endemic to small areas, usually confined to specific altitudes and substrates. Thus, Vellozia kolbekii (Alves 1992b), for which new localities are cited, is probably the first species of the genus for which a number of density surveys in stands was executed even before the species was described. Stands with other endemic species are also being studied. The fact that most species endemic to campo rupestre have small distribution areas means that they are usually endangered. Their survival depends on the protection of their entire stands, rather than protection of the isolated species. The knowledge of the vegetation in which they grow is scarce, but can be useful for their protection. Knowledge of local floras is still limited, and the list of endemic species will surely grow. The Serra de Sho Jos6 ranges from 900 to 1430 m in altitude, roughly between 21 ° 03-07' S. 44 ° 06-13' W. The Serra do Lenheiro rises from 880 to 1212 m.s.m., centred at 21 ° 09' S. 44 ° 19' W. and bordered at its southern foot by the city of S~o Jo~o Del Rei. The Itutinga range is truly represented by a series of relatively lower hillocks in higher ground, from 1000 to 1100 m, and the collection site there is 21 ° 19' S. 44 ° 39' W. Coordinates for the other ranges are: Serra de Ouro Branco (20 ° 23' S. 43 ° 42' W.), Ser- 126 ra Bico de Pedra (20 ° 28' S. 43 ° 42' W.), Serra de Carrancas (21 ° 22' S. 44 ° 40' W.). The Chapada Diamantina in Bahia has several ranges. Though we do not presently have the coordinates, the table mountains investigated were in the proximity of the town Rio de Contas, Palmeiras, Lencois, and Mucuge. The main studied ranges are shown in Fig. 1. The common factor of the sites where the mentioned species grow is basically the lithosolic composition of soils in which quartzites greatly predominate. Quartzite outcrops erode in a peculiar style, forming very uneven surfaces. Many of the white-sand savanna formations are the result of in situ erosion of these quartzites. The outcrops themselves provide substrate for Aylthonia tomentosa, Vellozia crassicaulis, and Vellozia kolbekii, while the remaining treated species thrive precisely in the mentioned white sands. The localities in question are aligned from WSW to ENE, forming the so-called S~o Jos6 geological formation. These quartzitic plateaus rise more or less abruptly from a landscape of red-yellow distrophic latossols with cerrado vegetation. This geomorphology is locally called 'mar de morros' (sea of hills). The dependence of lithophytical plants upon their specific substrate provides a reason for their restriction to the isolated ranges and their subsequent endemism. The climate is continental with a dry winter, 'Cwa' according to Ktippen (1936). Droughts culminate in July with averages of 8.6 mm rainfall and 9.9 °C, against 299.6 mm and 17.1 °C in January. Absolute temperatures range from a minimum of 1.0 to a maximum of 33.8 °C in that period. Methods The vegetation characteristics of these stands have been studied since 1986. Since 1989, over 600 vegetation relev6s have been executed, and part of this material, together with the usual floristic research, has been used as base-data for the present paper. The mean constancy percentages for each species are rounded to the nearest whole numbers. The environmental factors were studied in the main communities. Relevant taxonomic findings were also registered. Based on all theories and materials on the campos rupestres known to us, enhanced by our own microclimate measurements (Alves & Kolbek 1993), a new theory explaining the origin of endemism of the species from this type of vegetation was developed. BRAZIL MAIN CAMPO RUPESTRE RANGES ~ Q ¢c~J Fig. 1. Location of main studied campo rupestre areas, Significant endemism campo rupestre taxa with high Many campo rupestre species are only know from holotypes in herbaria. This is mainly due to their small areas of distribution and insufficient collecting. This is true for many species of the families Cactaceae, Cyperaceae, Eriocaulaceae, Euphorbiaceae, Lamiaceae, Melastomataceae, Myrtaceae, Orchidaceae, Velloziaceae, etc. According to Burman (1991) endemic species make up about 30% of the Espinhaqo range flora. Most of those species are actually restricted to isolated mountains or smaller ranges which make up part of the Espinhaqo complex. A list of the endemic species investigated by us is in Table 1. Species of the family Velloziaceae frequently dominate the stands on quartzitic table mountains of Minas Gerais. Smith (1990, pers. comm.) points out that the family is rich in species endemic to small areas, being many known only from type localities. Most small and isolated table mountains may be expected to have their very own species. Among the most representative cam- 127 Table 1. Main endemic species investigated to date in the studied ranges. D = dominant species, + = species with medium cover values, R = species with low cover values or rare species, X = occurring species. Ranges: A = Sao Jos6, B = Lenheiro, C = O u r o Branco, D = Carrancas, E = O u r o Grosso, F = Cip6, G = Chapada Diamantina. Species A B C Ranges D E Eugenia langsdorfii Berg. Croton gnidiaceus Baiil. Selaginellafragilima Air. Silv. Mesadenella meei R.J.V. Alves Aristolochia claussenii Duchartre Laelia mantiqueirae Pabst Aristolochia aff. gracilis Duchartre Stachytarpheta sellowiana Cham Pelexia phallocaUosa R.J.V. Alves Sarcoglottis caudata R.J.V. Alves Leiothrix prolifera (Bong.) Ruhl. Arthrocereus melanurus (Schum.) R R R Braun & al. + + R D R D D D D D - D Schultes D + D R Aristolochia gracilis Duchartre Aristolochia smilacina Hoehne Vellozia incurvata Ma~. ex R R - + - + F G + + R R D + R R R Sarcoglottis cogniauxiana (B.Rodr.) Schltr. Aylthonia tomentosa (Mart.) Menezes Vellozia kolbekii R.J.V. Alves Vellozia crinita Goeth. & Henr. Vellozia crassicaulis Mart. ex Schult. f. Vellozia crispata L.B. Smith Laelia endsfeldzii Pabst Jacaranda decurrens Cham Camarea affmis St. Hil. Polygala pseudo-erica St. Hil. po rupestre families, Burman (1991) reveals that all but 6 out of some 200 species of Velloziaceae are endemic to that vegetation type, in the Xyridaceae 100-150 out of 450, and that many Eriocaulaceae are also confined to this formation. The same author also reveals that some species of Vellozia are resinous and have been used as locomotive fuel on the Curvelo-Diamantina railway. The proportion of life forms in some stands dominated by Velloziaceae are in Table 2 and Fig. 2. Of the Velloziaceae, Aylthonia tomentosa is commonly found in the S~o Jos6, Lenheiro and Itutinga ranges, growing on relatively steep walls of quartzite R D + + + + R R + X X X + + + R + X - R cliffs. We also found it in the Carrancas range on micaceous schist walls facing north. The distribution mentioned by Smith & Ayensu (1976) is linked to a single specimen (Irwin et al. 29559). The type locality is equally vague, somewhere on the 160 km stretch between Ouro Preto and S~o JoAo Del Rei, or even in Diamantina, (Smith & Ayensu 1976). Our specimen matches perfectly that of Mello Barreto 4798, which was collected in the S~o Jos6 range. A confusion seems to persist among the species and their sites, which may be partly due to the variability in populations. Aylthonia tomentosa dominates saxicolous stands which include 128 Table 2. Species in stands dominated by Aylthonia tomentosa, Vellozia crassicaulis, I( crinita, and V. kolbekii (species endemic to campo rupestre are in boldface) in the S~to Jos6 Range. Mean constancy values are given based on 102 relev6s in the four communities. Predominant life forms are provided for each species according to the classification of Raunkiaer (1934). Ch= Chamaephyte, E= epiphyte, G= geophyte, H= hemicryptophyte, L= lithophyte, Ph= phanerophyte, Th= therophyte, a= mean constancy (%), b=- life form. Species in shrub layer (E2) Vanillosmopsis erythropappa Schult. Bip. Leandra aurea (Cham.) Cogn. Vellozia kolbekii Alves Lepidaploa ruJogrisea (St. Hil.) H. Robins. Aspilia sp. Croton gnidiaceus Baill. Eupatorium barbacense Hier. Rapania andina Mez Hyptisfruticosa Salzm, Stryphnodendron adstringens (Mart,) Coville Baccharis calvescens DC. Chionolaena cf. latifolia Bak, Chamaechrista brachypoda Benth, flex amara (Veil,) Loes. Byrsonima arctostaphylloides Nied. Cephea ericoides Cham. & Schltd. Byrsonima basiloba Adr, Juss. Myrcia mutabilis DC. Dasyphyllum macrocephala (Bak.) Cabr. Comotia sertularia (DC.) Triana Chamaechrista sp. Aloraia myriadenia (Schult. Bip.) Bak. Hyptis reticulata Mart. ex Benth. Ditassa sp. Vochysia thyrsoidea Pohl Clusia arrudea E & Tdana Miconia theaezans (Bonpl.) Cogn. Peixotoa tomentosa Adr. Juss. Miconia ligustroides (DC.) Naud. Gomidezia gaudichaudiana Berg. Hyptis complicata St. Hil. ex Bentb. llex integerrima (Veil.) Reiss. Myrcia suaveolens Camb. Paliavana lasiantha Wirth. Erythroxylum suberosum Mart. Jacaranda paucifoliata St. HiL Chaetostoma armature (Spreng.) Cogn. Gaylussacia brasiliensis (Spreng.) Meissn. Baccharis sp. Miconia peppericarpa DC, ab 48 Ph 47 Ph 35 Ph 23 Ph 23 Ph 16 Ph 16 Ph 15 Ph 15 Ph 11 Ph 11 Ph 10 Ph 9 Ph 8 Ph 7 Ph 6 Ph 6 Ph 6 Ph 6 Ph 5 Ph 5 Ph 5 Ph 4 Pb 4 Ph 4 Ph 4 Pit 3 Ph 3 Ph 3 Ph 2 Ph 2 Ph 2 Ph 2 Ph 2 Ph 2 Ph 2 Ph 1 Ph 1 Ph 1 Ph 1 Ph Family Asteraceae Melastomataceae Velloziaceae Asteraceae Asteraceae Euphorbiaceae Asteraceae Myrsinaceae Lamiaceae Mimosaceae Asteraceae Asteraceae Caesafpiniaceae AqMfoliaceae Malpighiaceae Lythraceae Matpighiaceae Myrtaceae Asteraceae MeIastomataceae Caesalpiniaceae Asteraceae Lamiaceae Asclepiadaceae Vochysiaceae Clusiaceae MeIastomataceae Malpighiaceae Melastomataceae Myrtaceae Lamiaceae Aquifotiaceae Myrtaceae Gesneriaceae Erythroxylaceae Bignoniaceae Melastomataceae Ericaceae Asteraceae Melastomataceae 129 Table 2. Continued. Species in shrub layer (E2) ab Family Podocarpus lamberti Klotzsch Chamaechrista cathartica Mart. Lippia lupulina Chain. & Schlecht. Peixotoa catarinensis C. Anderson 1illandsia stricta Soland vat, stricta ?~llandsia tenuifolia L. Tacoyenaformosa K. Schum. Usnea el, rubicunda Stilt. Austroplenckia populnea Reiss. Bulbophyllum ipanemensis Hoelme Croton antisyphiliticus Mart. Peixotoa sp. Psittacanthus robustus Mart. (epiphytic parasite on Vochysia thyrsoidea 1 Ph l Ph 1 Ph 1 Ph 1E 1E 1 Ph 1E l Ph 1E 1 Ph 1 Ph 1E Podocarpaceae Caesalpiniaceae Verbenaceae Malpighiaceae Bromeliaceae Bromeliaceae Rubiaceae Usneaceae Celastraceae Orchidaceae Euphorbiaceae Malpighiaceae Loranthaceae Species in ground layer (Et) Melinis minutiflora P. Beaav, Leandra aurea (Chain.) Cogn. Loudetiopsis chrysothrix (Nees,) J. Felir Cuphea ericoides Chain. & Schltd. Lagenocarpus rigidus Nees Bulbostylis lagoensis Boeck. Andropogon leucostachyus H.B.K. Borreria brachystemonoides Chain, & Schltd, Vellozia crinita Goeth. & Henr. Arthrocereus melanurus (Schum.) Braun et al. Rhynchospora globosa R. & S. Vellozia kolbekii Alves Alomia myriadenia (Schult, Bip.) Bak. Vellozia crassicaulis Mart, ex Schult. Laelia mantiqueirae Pabst Aylthonia tomentosa (Mart,) Menezes Vanillosmopsis erythropappa Schult. Bip, Doryopteris ornithopus (Mett.) J.Srnith Senecio adamantinus Bong. Euphorbia coecorum Mart, Polypodium lepidopteris (Langsd. & Fisch.) Kze. Portulaca mucronata Link, Eupatorium barbacense Hier. Splecklinia rupestris (Lind.) E Barros Dipladenia gentianoides Z. Br. Aspilia sp, m a n y s p e c i e s o f Orchidaceae, a n d s o m e Bromeliaceae a n d Cactaceae, a n d w h i c h are d e n s e l y c o v e r e d w i t h encrusting lichens. The most intense flowering occurs from January to March, but individual plants flower 66 H 59 Ph 54 H 50 Ch 50 H 42 H 40 H 37 Ch 35 Ch 33 Ch 31 H 30 Ph 29 Ch 29 Ph 29 L 28 L 27 Ph 24 Ch 19 Ch 17 G 16 ChlLIE 15 Ch 15 Ph 15 L 14 G 12 Ph Poaceae Melastomataceae Poaceae Lythraceae Cyperaceae Cyperaceae Poaceae Rubiaceae Velloziaceae Cactaceae Cyperaceae Velloziaceae Asteraceae Velloziaceae Orchidaceae Velloziaceae Asteraceae PoIypodiaceae Asteraceae Euphorbiaceae Polypodiaceae Portulacaceae Asteraceae Orchidaceae Apocynaceae Asteraceae d u r i n g t h e w h o l e year. F u r t h e r field s t u d i e s a r e n e c e s sary for a n a t t e m p t at d e f i n i n g t h e d i s t r i b u t i o n o f this species, as well as m a n y s i m i l a r t a x a v i c a r i o u s w i t h it o n n e a r b y m o u n t a i n r a n g e s , a n d e v e n as f a r as t h e 130 Table 2. Continued. Species in ground layer (El) ab Croton gnidiaceus Baili. Xyrius asperula Kunth Peperioma decora Dahlst. vat. decora Klotzschia brasiliensis Cham. Marcetia taxifolia (St. Hil.) DC. Cuphea thymoides Chain. & Schltd. Syngonanthus niveus (Bong.) Ruhl. Xyris bahiana Malme Cryptanthus schwackeanus Mez. Sida cf. rhombifolia L. Rhynchospora consanguinea Boeck. Stachytarpheta seUowiana Schau. Aechmea nudicaulis (L.) Griseb. Dyckia argentea Mez Ditassa sp. Chamaechrista sp. Borreria sp. Bulbophyllum ipanemensis Hoehne Gomphrena agrestris Mart. Polygala paniculata L. Comolia sertularia (DC.) Triana Syngonanthus gracilis (Koern.) Ruhl. Vigna sp. Spigelia heliotropoides Guim. & Font. Xyris rupicola Kunth Aristolochia gracilis Ducht. Tillandsia gardneri Lindl. Phyllanthus niruri L. Oncidium blanchetii Rchb. f. Senna bicapsularis (L.) Roxb. Xyris hymenachne Mart. Rapania andina Mez Vernonia linearifolia Gatdn. Bulbostylis paradoxa (Spreng.) Clarke Anemia villosa Willd. Anacheilium vespum (VEIL) Dressler sp. agg. Elaphoglossum sp. cf. Briza sp. Anthurium sellowianum Kunth Hyptis complicata (St. Hil.) ex Benth. outcrops on the Pai IMcio hill in Bahia. Vellozia kolbekii was found in three localities, roughly 60 km apart. The best studied locality of these is the S~o Jos6 range in which several large populations occur (Fig. 3). It grows on unevenly eroded quartzite outcrops with or without a layer of fine sand and grav- 12 Ph 11 H 11 L 10 G 10 Ph 9 Ch 9 Th 9H 8L 8 Ch 8 Ch 8 Ph 8L 7L 7 Ch 7 Ph 7 Ch 7L 6 Ch 6 Ch 6 Ph 6 Th 5H 5 Ch 5H 5H 5L 5 Ch 4 Ch 4 Ph 4H 4 Ph 4 Ph 4H 4 Ch 4L 3L 3 Ch 3L 3 Ph Family Euphorbiaceae Xyridaceae Piperaceae Apiaceae Melastomataceae Lythraceae Eriocaulaceae Xyridaceae Bromeliaceae Malvaceae Cyperaceae Verbenaceae Bromeliaceae Bromeliaceae Asclepiadaceae Caesalpiniaceae Rubiaceae Orchidaceae Amaranthaceae P olygalaceae Melastomataceae Eriocaulaceae Fabaceae Loganiaceae Xyridaceae A ristolochiaceae Bromeliaceae Euphorbiaceae Orchidaceae Caesalpiniaceae Xyridaceae Myrsinaceae Asteraceae Cyperaceae Schizeaceae Orchidaceae Aspidiaceae Poaceae Araceae Lamiaceae el, (usually on bare rock and without any apparent preference for the cracks and ledges in it). The second locality is west of the city of S~o Jo~o Del Rei, in the Lenheiro range. Populations here are smaller and more isolated, partly due to human exploitation (mining and overgrazing), and in part to the more heterogenous soil 131 Table 2. Continued. Species in ground layer (El) ab Family Stryphnodendron adstringens (Mart,) Coville Chaetostoma luteum Cogn. Hyptis conferta Pohl Microlicia cinerea Cogn. Cyperus cf. cyperinus (Vahl) Suringar Eremanthus speciosus Bak. Dyckia sp. Sauvagesia rubiginosa St. Hil. Pfaffia helychrisoides (Moq.) Kuntze Miconia ligustroides (DC.) Naud. Lepidaploa rufogrisea (St. Hil.) H. Robins Anemia elegans Pohl. Dasyphyllum brasiliensis (Spreng.) Cabr. Lycnophora passerina (Mart. ex D.C.) Gardn. Chamaechrista rotundifolia Pers. Hyptisfruticosa Salzm. Trimeziajuncifolia (Klatt.) Benth. & Hook. f. Erythroxylum suberosum St. Hil. Spigelia scabra Cham. & Schltd. Lagenocarpus polyphyllus Kuntze Gaylussacia montana (Pohl) Sleumer Peperomia subrubrispica C. DC. Gomidezia a~nis (Camb.) Legr. Leucothose crassifolia (Pohl.) DC. Clusia arrudea PI. & Triana 3 Ph 3 Ch 3 Ph 3 Ch 3H Mimosaceae Melastomataceae Lamiaceae Melastomataceae Cyperaceae Asteraceae Bromeliaceae Ochnaceae Amaranthaceae Melastomataceae Asteraceae Schizeaceae Asteraceae Asteraceae Caesalpiniaceae Lamiaceae lridaceae Erythroxyllaceae Loganiaceae Cyperaceae Ericaceae Piperaceae Myrtaceae Ericaceae Clusiaceae 3H 3L 3 Ch 3 Ch 3 Ph 3 Ph 3L 2 Ph 2 Ph 2 Ch 2 Ph 2G 2 Ph 2 Ch 2 Ch 2 Ph 2L 2 Ph 2 Ph 2 Ph Species with 1% constancy only (Ground layer): Achyrocline albicans Griseb. [Ch], Aechraea bromeliifolia (Rudge) Baker [El, Baccharis calvescens DC. [Phi, Bulbophyllum bidentatum (B. aodr.) Cogn. [L], Bulbostylis sp. [Ch], Byrsonima basiloba Adr. Juss. [Phi, Camaridium rigidum B, Rodr, [L], Carex sp. [Ch], Chamaechrista brachypoda Benth. [Ph], Chamaechrista cathartica Mart. [Phi, Commelina agraria Kunth [Ch], Coccocypselum erythrocephalum Chain. & Schltd. [Ch], Gaylussacia ridelii Meissn. [Phi, Glaziovanthus curumbensis (Phil.) Macleen [HI, Gomphrena officinalis Mart. [Ch], Hatiora aff. salicornioides (Haw.) Br. & R. ILl, Hippeastrum of. equestre (Ait.) Herb. [G], Kalanchoe brasiliensis Camb. [Ch/L], Leiothrix proh'fera (Bong.) Ruhl. [Th], Maxillaria acicularis Herb. [L], Miconia cf. sellowiana Naud. [Phi, Miconia theaezans (Bompl.) Cong. [Phi, Microlicia isophylla DC. [Ch], Microlicia spec. [Ch], Ditassa sp. II [Ch], Peixotoa catarinensis C. Anderson [Phi, Peixotoa tomentosa Adr. Juss. [Ph], Rumex sp. [Th], Poaceae I [Ch], Poaceae II [Cb]. c o m p o s i t i o n o f this range. T h e densest stands of V. k o l b e k i i were f o u n d in the third locality, in the Ouro G r o s s o range. This p o p u l a t i o n forms thickets on the southern slopes o f l o w - l y i n g quartzite outcrops which face the Carrancas range s o m e 20 k m yonder. It c a n be reached from the B a r b a c e n a - L a v r a s road b y p a r k i n g at the 100 k m m a r k e r b r i d g e over the Rio G r a n d e and h i k i n g some 1200 m south. 132 LIFE FORM S P E C T R U M ~Y SP~C LIFE FORM S P E C T R U M CONStANt-CORRECTED I ~ TH (2.3Z) L (1 1.5X) TH (1oIZ) L (10,1Z) CH (23.0X) 3.8x) H (I 8.5~) O (3.4x) E (1.4x) E (4.ox) G (2.9X) Ph (47.1X) Ph (42.~) F i g . 2. (left) Life form spectrum of the stands in Table 2, based on floristic data. (right) The previous life form spectrum (corrected by constancy values to better illustrate the vegetational aspect). Ch=Chamaephyte, E=epiphyte, G=geophyte, H=hemicryptophyte, L=lithophyte, Ph=phanerophyte, Th=therophyte. Fig. 3. Stand of Vellozia kolbekii in the S~o Jos6 range. Vellozia crassicaulis was observed in dense stands on quartzite outcrops of the S~o Jos6 range, especially on the north-facing slopes at higher altitudes. This species has been collected more frequently and in a wider distribution range (Smith & Ayensu 1976) in the states of Minas Gerais, Goias and Mato Grosso. However, it had not been previously recorded for the S~o Jos6 range. 133 Fig. 4. Table mountain with campo rupestre in the Sao Jos6 range - Aerial Photograph approx. 1:30.000. Vellozia crinita, curiously, was known only from the type specimen until the date of the revision (Smith & Ayensu 1976). Since 1988 the occurrence of V. crinita was a commonly accepted fact to us in the S~o Jos6 range, and in the same year stands were also found in the vicinity of Itutinga. This species grows in white sands, forming a network of small creeping caudex-mounds, which apparently grow at a very slow rate. The type specimen was collected in the S~o Jos6 range itself (Glaziou 16,388). Smith & Ayensu (1976) expressed doubt as to wether Glaziou's locality was not S~o Joao Del Rei (Lenheiro range), but this resulted from the renaming of what was then called Villa de S~o Jos6 d'el Rey, and is now known as Tiradentes. The adjacent mountain range preserved its old name according to the nearby town, still being known as Serra S~o Jos6. Nevertheless the species was also found in the Lenheiro range, occurring in several of our relev6s. Eugenia langsdorfii is apparently endemic to the region between Lavras and the S~o Jos6 range. The species was rarely collected and seems to be restricted to a small number of table-mountains. E. langsdorfii grows on white sands in campo rupestre formations that have periodic natural fires. Scree mixed with white sand seems to be a favorable combination of substrates, with gravel size from 3 to 6 cm in diameter. This species was seldom found in relev6s. Eugenia langsdorfii was found growing mostly in the sparse shrub layer of open stands (Table 3). This stand grew on a cliff slope, covering 20% of the surface, the rest being exposed bedrock. The soil was only a white sand layer with a maximum depth of 5 cm. For Sarcoglottis cogniauxiana, Hoehne (1945) provides a full description, but the illustration bears certain discrepancies which indicate that it had been made from a herbarium specimen. This species was already known by Cogniaux (1893-1906), who provided a color plate in an unpublished part of his 'Icon. Orch. Bresil'. Hoehne's diagnosis of the live plant (Hoehne 1945:329) fits our field observations perfectly, there being no doubt as to the identity of this endemic species. The distribution cited is the city S~o Jo~o d'el Rei in Minas Gerais. This town, is located at the eastern base of the Serra do Lenheiro, where we collected a specimen on November 1st, 1989. The new locality for this species is the range called Serra de S~o Jos6, east of Tiradentes. In both ranges the species grows in the bleached sands which frequently include a high content 134 Table 3. S p e c i e s in s t a n d in w h i c h Sarcoglottis cogniauxiana (a) a n d Eugenia langsdorfii (b) w e r e r e c o r d e d in t h e S~o Jos~ r a n g e . A s i m p l e c o m b i n e d s c a l e o f c o v e r a n d a b u n d a n c e is u s e d to i n d i c a t e t h e i r s i g n i f i c a n c e in the s t u d i e d stands, D = d o m i n a n t s p e c i e s , + = s p e c i e s w i t h m e d i u m c o v e r v a l u e s . R = s p e c i e s w i t h l o w c o v e r v a l u e s or r a r e s p e c i e s , Shrub layer (E2) a b Family Vellozia kolbekii Alves Leandra aurea (Chain.) Cogn. Aspilia sp. Vanillosmopxis eo,thropappa Schutt. Bip. Hyptis lantan(~dia Poit. Camaechrista brachypoda Benth. Byrsonima arctostaphylloides Nied. Chaetostoma armature (Spreng.) Cogn. D R + R R R Velloziaceae Melastomataceae msteraceae Asteraceae Lamiaceae Caesafpiniaceae Matpighiaceae Melo.vtomataceae D - + - R - R - + - Ground layer (E I ) Sarcoglottis cogniauxiana (B. Rodr.) Schltr, Eugenia langdsorfii Berg Bulbostylis capillaris (L.) Clarke l.xJudetiopsis chrysothrix (Nees) J. Felir Lagenocarpus rigidus (Kunth.) Nees Metinis rainutiflora H.B.K. Cuphea ericoides Chain, & Schl. Leandra aurea (Chain.) Cogn. Vanillosmopsis erythropappa Sehult. Bip. Laelia mantiqueirae Pabst Vellozia ~dbela'i R.J.V. Alves Vellozia crassicaulis Mart. Arthrocereus melwzurus (Schum.) Braun et al. Eupamrium barbacenae Hier. Andropogon tener Kunth Chamaechrista sp. Stenorrhynct~r lanceolatus (Aubl.) L.C. Rich. Buchnera lavandutaceae (:ham. & Schl. Doryopreris ornithopus (Mett.) J. Smith Sauvagesia rubiginosa St. Hit. Senecio sp. Polypodium lepidopteris (Langsd. & Fisch,) Kz¢. Portulaca mucronata Lindl. Cryptanthus schwackeanus Mez Rhynchospora globosa R. & S. Xyris bahiana Malme Microlicia isophylla DC. vat. stenophylla Cogn. Lepidaploa rufogrisea (St. Hil,) H. Robins Klotz.~chia brasiliensis Cham. Xyris asperula Kunth R - - R D + D R + D + R + R + R + R R R - D - D + - + - + - R - R -- R - R - R - R R - R -- R - D - + - R - R -- R -- R - Shrub layer (E2) Ground layer (Et) 20 40 5 35 Moss layer (Eo) 50 40 Cover (%) Orchidaceae Myrlaceae Cyperaceae Poaceae Cyperaceae Poaceae Lythraceae Melastomataceae Asteraceae Orchidaceae Velloziaceae Velloziaceae Cactaceae Asteraceae Poaceae Caesalpiniaceae Orchidaceae Scrophutariaceae Potypodiaceae Ochnaceae Asteraceae Polypodiaceae Portulacaceae Bromeliaceae C3peraceae Xyridaceae Melastomataceae Asteraceae Apiaceae Xyridaceae 135 of milky-quartz gravel. Stands with this species consist of a relatively continuous herbaceous cover composed of species of Lagenocarpus, Bulbostylis, Xyris, and Andropogon. Sparsely scattered woody species do not create a true layer here (Table 3). The sand layer is about 30 cm deep, directly on a solid quartzite basement. All flowering individuals observed were leafless. Though the presence of leaves at anthesis is used as a taxonomic character by Pabst & Dungs (1975, 1977), it has limited systematic value. Many Spiranthinae flourish maintaining their leaves when they grow in stands with a dense shrub or tree cover, whereas the same species bloom leafless on more exposed sites. We observed these conditions for Stenorrhynchus lanceolatus (Aubl.) L.C.Rich, Eltroplectris triloba (Lindl.) Pabst, and numerous other species. Considering the present desolate state in which the Lenheiro range, the occurrence of Sarcoglottis cogniauxiana in the S~o Jose range is relevant for the survival of this rare endemic. Populations are very sparse even in its natural stands. A moss and lichen layer with 10% cover (50% on rocks) was present. Croton gnidiaceus is another endemic species of the Sao Jose range. It is closely related to C. timandroides, which occurs endemically in the Serra do Cip6. It was not found in nearby ranges. Croton gnidiaceus occurs mainly in stands with Vellozia kolbekii, where it has a 17% constancy. It occurs in at least 10 relevEs as an additional species. Discussion Campos rupestres and tepuis topographically act as quartzite and sandstone islands emerging from a sea of unrelated substrates such as laterite (Fig. 4). In Brazil, the term 'mar de morros' is frequently used to describe the rugged cerrado landscape that surrounds the campo rupestre mountain ranges. Mainly thanks to this insulax effect, endemic species play an important role in the composition of campo rupestre floras. Many campo rupestre species are only known from holotypes in herbaria. This is mainly due to their small areas of distribution and insufficient collecting. This is well known about many species of the families Cactaceae, Cyperaceae, Eriocaulaceae, Euphorbiaceae, Lamiaceae, Melastomataceae, Myrtaceae, Orchidaceae, Velloziaceae, etc. A basic technical insufficiency of most distribution surveys published so far is that they fail to distinguish between non-occurring and unfound species, which are both registered as nill. Thus white spots on distribution maps can have two meanings. According to Burman (1991) endemic species make up about 30% of the Espinhaqo range flora. Most of those species are actually restricted to isolated mountains or smaller ranges which make part of the Espinha~o complex. Among the most representative campo rupestre families, Burman (1991) reveals species of Velloziaceae, Xyridaceae, and many Eriocaulaceae, and also that some species of Vellozia are resinous and have been used as locomotive fuel, Curvelo-Diamantina railway. This is why Vellozia spp. are known in Bahia as 'Candomba', a word derived from the Tupi-Guarani indigenous words language. A large Vellozia, according to Burman (1991), can take up to 100 years to reach 'adult' stage. On a field trip to the Ouro Branco range with Johann Becker in 1990, we came across specimens of VeUozia sp. over 4 m high, and estimated the age of individuals of V incurvata, with shorter stature, at over 500 years. Sarcoglottis caudata, Liparis beckeri, Pelexia phaUocallosa, Eugenia langsdorfii, and Croton gnidiaceus are strict endemics of the Sao Jose range. Sarcoglottis cogniauxiana, Leiothrix prolifera, and Selaginellafragillima only occur in the Serra SAo Jose and adjacent Lenheiro range. Vellozia virgata is a mysterious species collected by Glaziou in the SAo Jose range in 1889. It is apparently known only from the type specimen and from an uncited collection on Pico Itabira do Campo, about 120 km north (Smith & Ayensu 1976:51). Some preliminary studies on the distribution patterns of certain taxa throughout the campos rupestres (Giulietti & Pirani 1988; Harley & Simmons 1988; Barros 1990) have been published. Despite the present limitations of our knowledge on this subject, they clearly demonstrate unequal distribution tendencies within some of the main taxa (usually families). Most species of the Velloziaceae are confined to smaller ranges, and a few, like Vellozia dasypus Seub. (Harley & Simmons 1988:100) have disjunct distributions, occurring in the campo rupestre and in the restinga (sandy coastal strand vegetation) north of Salvador. The same author mentions that Mandevilla moricandiana (DC.) Woods. of the Apocynaceae has also been found in restinga and campo rupestre, and our own collections in the Sao Jose range and in the Maricd restinga in Rio de Janeiro confirm this. Other species like Bonnetia stricta, Marcetia taxifolia, Couma rigida, Evolvulus jacobinus and Anthurium affine (Harley & Simmons 1986, 1988) share this disjunct distribution. Giulietti & Pirani (1988) believe these species to be indigenous 136 to the Espinhaqo chain and secondary in the restingas. The question of how their diaspores reached places so remote still remains. Not much is presently known about disjunct distribution patterns for campo rupestre species. Beach strand vegetation is known to be vicarious around the world, and some species of these communities are more widely distributed (Kolbek & Alves 1993). The fact that restinga vegetation occurs in an extremely humid coastal climate suggests that campos rupestres may not be as arid as certain authors claim (see further). Harley & Simmons (1986:9) suggests that high endemicity in certain campos rupestres 'is probably due to speciation as a response to local, not necessarily present-day, conditions, and partly due to reliction and extinction, following range contraction of formerly more widespread species as a result of climatic changes'. Giulietti & Pirani (1988:47) further claim that species which occur disjunctly in the Espinhaqo chain and in the serras of Goi~ts (which have similar geological, physical and climatic features), 'provide evidence of former epochs when there were major links between the floras of these regions'. The high number of endemic species which are vicarious from range to range indubitably testifies links, but with the present state of knowledge we can only speculate about their specific nature. According to Ramos (1986), between 1650--950 million years ago, a lacustrine (shallow sea or lake) environment existed in the area of the S~o Jos6 range. Due to the presence of ripple marks in quartzites from the Espinha~o chain ranges, we may suppose their formation conditions to have been similar. The tectonics which raised the campo rupestre ranges from among latosol surroundings supposedly occurred between 950-650 million years ago, during the last geotectonic cycle. Latosols, which are older, have apparently been separating the outcrop ranges since then. This mainly edaphic contrast is responsible for the potential isolation barriers between individual stands of campo rupestre. On a broad scale the greatest climatic differences are found between the three main campo rupestre chains. The Espinhaqo chain within the zone with annual rainfall above 1250 mm; the Chapada Diamantina, with less than 1000 mm (but the N and S sides of this complex have profoundly distinct rainfall patterns: the south side near Rio de Contas is much drier than the more northern Palmeiras and Lencois vicinity); and the serras of Goi~is with over 1500 mm. Nimer & Brand~o (1989:13) state that 'the plant asso- ciations of the cerrados are apparently constituted of an ecological climax linked to both climatic and edaphic factors'. They present a series of maps with a broader zonation of climatic factors, but the S~o Jost, Ouro Branco and Ouro Preto ranges lie south, beyond their proposed 'cerrado region'. In truth, the typical cerrado zone extends through Lavras as far south as Pirassununga in the state of Sao Paulo. Despite this, we have placed annual rainfall zones on one map with lithosolic soils in order to provide an approximate notion of their possible influence on the formation of campo rupestre vegetation (Alves 1992a). When isolated mountains and ranges (such as campo rupestre serras) rise from relatively flat terrain, they frequently provoke condensation of rain from the passing cloud cover. On relatively clear days the few existent clouds only condense when they pass over the summits of the tall peaks. This precipitation excess is unaccounted for by nearby meteorological stations. At first sight the campo rupestre areas may thus seem more arid than they really are, and available meteorological data, even from nearby stations, may be misleading. An exception seems to be the station of S~o Jo~o Del Rei - - in a campo rupestre at 991 m s.m. in the Lenheiro range, with an average annual rainfall of 1467.4 mm. As Harley & Simmons (1986) agree, high nocturnal drops in temperature cause dew condensation which compensates for part of the hydric deficiency. According to Nimer & Brand~o (1989: fig. 11), the states of Minas Gerais and Bahia annually have from 5 to 10 months of hydric deficiency (from 5 to 7 along the Espinhaqo chain and adjacent land). Based on the abundance of Cactaceae, some authors like Siqueira (1988) have speculated that the area now comprising campo rupestre vegetation was more arid in the past, mainly due to studies from the Amazon region. The numerous similar species of Cactaceae in the region are found in disjunct areas, as is also the case of many Orchidaceae, Melastomataceae, Eriocaulaceae and Velloziaceae. Thus some researchers attribute to campos rupestres the role of refugia for xerophytic species after the invasion of a moister climate. Harley & Simmons (1988:113)recognize the need of further fossil evidence to support this and states that 'Apart from requiring a more specialised substrate, usually associated with impervious rocks, the climatic regime which suite them [campo rupestre species] while distinctly seasonal, is cooler and more humid, the aridity tempered with rain and dew from the atmosphere, suggesting marked diurnal changes in temperature'. These climatic observations generally 137 agree our field data. Even in a generally more arid environment, these mountains were probably moister than their surroundings. They further suggest that the campo rupestre mountain ranges could have acted as refugia during adverse periods. We believe that the confinement of xerophytic species to these mountain ranges (and their relative absence from surrounding terrain) is due mainly to edaphic conditions. The lithosolic nature of their soils could hardly have supported the suggested Quaternary forest refugia, as most non-campo rupestre plant species would not survive the harsh environmental conditions. The development of saxicolous plants ancestral to those found presently in campos rupestres can only have begun after the Silurean, when some plants had definitely become adapted to terrestrial conditions. (The Magnoliopsida only appeared during the Jurassic.) We believe most endemic campo rupestre species have probably developed as recently as the Pleistocene (Fig. 5). Hammen (1974) supposes that three cool dry periods should have occurred, approximately between 20,000-13,000, 11,000-9,500, and 3,500-2,800 years ago, but not much is known about local conditions in Brazil of that era. The abundance and considerable depth of laterites indicates that they are usually much older than the Pleistocene (Smol~ov~i 1982). This should also be valid in areas adjacent to campos rupestres. Latosols such as those surrounding the S~o Jos6 range have been formed by the action of humid tropical intemperism, and this opposes the pastdrought theory. This same intemperism (by differentially eroding quartzite outcrops) has formed the sand and gravel beds atop table mountains and at their bases. These are characteristic soils for some campo rupestre vegetation types. Hence the edaphic contrast between campo rupestre and surrounding terrain has apparently existed for a long period. Many succulent herbs, mainly orchids and cacti, grow both epiphytically and lithophytically. Epiphytism is usually understood as a strategy linked primarily to illumination conditions of tree crowns as contrasted with by those of the forest understory. The same principle probably applies to lithophytes, though the environment is usually even dryer and substrate temperatures become higher than on trees. Due to fast runoff in both cases, water absorption by the plants is more dependent on duration of rain or dew than on total rainfall. The effect of nutrient poverty of campo rupestre soils (usually bleached sands) is almost analogous to aluminium content in laterites, and to conditions caused by high runoff on tree bark. In the EVENT E ~ D E M ~ c CAMPO F~R~T MAQNO~OP~D~ YEARS A G O x I0 ~ 0 "1 t 135--180 t F~T~T~T~-~ST~= 400~40 t ~=~N~.OO~~O~ T~:-~ 950--650 t Fig. 5. Illustrative chronogram of main events which were a prerequisite to the advent of endemic campo rupestre species. above cases, though due to distinct causes, availability of nutrients to plants is limited. We agree with Barros (1990), in that part of the present campo rupestre lithophytes may have originated from epiphytes of nearby cerrados and gallery forests. Many campo rupestre plant species thrive well in artificial conditions which strongly differ from those in their present natural habitat. Orchids, bromeliads and some cacti grown in constantly humid greenhouses are examples of plants which develop into stronger, more robust individuals when grown in a greenhouse. Though campo rupestre plants are highly tolerant to long drought and thermal oscillations with extreme minima and maxima in their natural habitat, these conditions are an environmental stress factor and not a requirement of the species. They grow in campos rupestres thanks to their unique morpho-physiological adaptations (like the CAM metabolism), and usually fail to occur in the surrounding vegetation (like cerrado) either due to stronger competition from other species or possibly due to their inability to thrive on latossol, due to high aluminium content, for example. Of the grasses, Diandrostachya (Loudetiopsis) chrysothrix is probably the most typical campo rupestre species. The barbed glumes indicate a possible epizoochoric dispersal in addition to anemochory, and this may help explain the relatively broad distribution of this species. The same may be valid for the sedge Lagenocarpus rigidus, which is widely dispersed on most campos rupestres. Dispersal barriers such as geographic isolation of one campo rupestre from another may have accelerated speciation in situ and resulted in a higher rate of endemism. This seems 138 to be supported by the fact that most Myrtaceae (usually endozoochoric) have a wider distribution throughout campos rupestres than families in which other dispersal mechanisms predominate. A more detailed correlation of dispersal strategies should shed light on the causes of campo rupestre dispersal patterns. Presently the main efforts should, in our opinion, be directed toward enhancement of floristic knowledge which can then serve as a base for distribution surveys. Conclusions Based on the above discussed aspects, we concluded that most known endemic species in the campos rupestres so far studied have probably originated locally from c o m m o n ancestral species. The inability to grow on the much older latosolic soils which surround the table mountains indicates that they are not relicts of previously more dispersed populations (Alves 1992a). Evidence of the relative ages of these substrate types is suggested by the presence of small lateritic hardpans and deposits with cerrado plant species on top of many table mountains. Furthermore, the distribution of vicarious species on nearby table mountains also supports the in situ speciation, as does the occurrence of several very related species on the same table mountain, for ex. Bulbophyllum ipanemensis, B. teresensis, B. weddellii, B. spp. aff. in the S~o Jos6 range (Alves 1991). Furthermore, the available moisture on these table mountains is more abundant than in the surrounding cerrados, due to orographic condensations and frequent mist. This apparently refutes previous theories which stated that the campo rupestre species are relicts of more arid climates. Life on the table mountains is edaphically and otherwise so isolated from the surrounding cerrado, that one can not deduce any significant climatic changes for this region as was attempted by other authors. The insular status of table mountains has endowed the campos rupestres with many endemic species. The articulate geomorphology of the campo rupestre ranges provides isolation barriers, which prevent the migration of certain species between the ranges or even between individual mountains of the same range. Mosaic distribution of soil types contributes to this isolation. Populations of many endemic campo rupestre species are thus restricted to extremely small areas. Another factor which contributes to the restricted dispersal of these species is their slow metabolism due to nutrient-poor substrates, in lithophytic species enhanced by extreme substrate temperature oscillations. These species are evidently more easily endangered than those with broad distribution. Based on our field observations from the campos rupestres, the mentioned species should be considered endangered. Knowledge of the vegetation and site characteristics in which they grow is the first prerequisite for the successful conservation of these species. Many other endemic plant species are likely to become endangered in the near future. Unfortunately, knowledge about isolated species has seldom helped in their conservation in Brazil. Seeds have been collected from some of the treated species for attempted propagation and were distributed to numerous growers which have not yet reported their results. Acknowledgements The authors thank two referees for constructive criticism and literature references. References Alves, R. J. V. 1991. Field guide to the orchids of the Serra de S,~o Jos6. Guia de campo das orqufdeas da Serra de S~o Jos6. Tropicaleaf, 148 pp., Praha. Alves, R. J. V. 1992a. The flora and vegetation of the Serra de Siio Jos6 in Minas Gerais, Brazil. Thesis, 114 pp. [Botan. Inst. Czechoslovak Academy of Sciences, Pruhonice]. Alves, R. J. V. 1992b. Sarcoglottis caudata (Orchidaceae) and Velloziakolbekii (Velloziaceae), two new species from Minas Gerais, Brazil. Novon, St. Louis 2: 299-301. Alves, R. J. V. & Kolbek, J. 1993. Penumbral rock and sand communicaties in campo rupestre sites in Brazil. Journ. Veget. Sci., Uppsala 4: 357-366. Barros, E 1990. Diversidade taxonOmica e distribuic~o geogrfifica das Orchidaceae Brasileiras. Acta Bot. Brasil. 4: 177-187. Burman, A. 1991. Saving Brazil's savannas. New Scientist, London, 129: 30-34. Cogniaux, A. 1893-1906. Orchidaceae. In: Martius' Flora Brasiliensis, Vol. 3, Tom. 4---6. Donselaar, J. van. 1965. An ecological and phytogeographic study of northern Surinam savannas. Wentia 14:1-163. Giulietti, A. M. & Pirani, J. R. 1988. Patterns of geographic distribution of some plant species from the Espinha~o range, Minas GerMs and Bahia, Brazil. In: Heyer, W. A. & Vanzolini, P. E. eds., Proceedings of a workshop on neotropical distribution patterns, pp. 39-69, Rio de Janeiro, Acad. Bras. 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Fundaq~o Brasil. de Geogr~if. e Estatfst. (IBGE), 162 pp., Rio de Janeiro. Pabst, G. E J. & Dungs, E 1975, 1977. Orchidaceae brasilienses. Vol. 1, 408 pp., Vol. 2, 418 pp., Brucke Verlag, Hildesheim. Ramos, R. R. C. 1986. Sintese geol6gica da Serra de S~o Jos6 (Tiradentes - MG). ms. [depon. by R. Alves] Raunkiaer, C. 1934. The life forms of plants and statistical plant geography. Being the collected papers of C. Raunkiaer. Clarendon Press, Oxford. Silveira, A. A. da. 1931. Floralia Montium. Vol. 2, pp. 322339, Imprensa Oficial de Minas Gerais, Belo Horizonte. Siqueira, J. C. da. 1988. Curso de adapta~6es morfol6gicas nos vegetais, ms. [annot. by R. Alves during the course] Smith, L. B. & Ayensu, E. S. 1976. A revision of the American Velloziaceae. In: Smithsonian Contr. Bot. 30, 172 pp., Smithsonian Inst., Washington. Smolfkov~i, L. 1982. Pedologie I, & II. St~it. Pedag. Nakl., Praha, 294 pp.
