Acta bot. bras. 15(3): 289-304. 2001 289 FLORISTIC COMPOSITION OF THE CERRADO IN THE PÉ-DE-GIGANTE RESER- VE (SANTA RITA DO PASSA QUATRO, SOUTHEASTERN BRAZIL) Marco Antônio Batalha1 Waldir Mantovani2 Recebido em 04/02/00. Aceito em 25/07/01. RESUMO – (Composição florística do cerrado na Reserva Pé-de-Gigante (Santa Rita do Passa Quatro, SP)). Estudamos uma área de 1225 ha, composta principalmente por cerrado, situada em Santa Rita do Passa Quatro, estado de São Paulo (21°36-38’S, 47°36-39’W). Em três fisionomias de cerrado (campo cerrado, cerrado sensu stricto e cerradão), coletamos, durante 18 meses, em excursões mensais, espécimes em fase fértil e os identifica- mos em nível específico. Encontramos 360 espécies, pertencentes a 236 gêneros e 69 famílias. As famílias mais ricas foram: Fabaceae, Asteraceae, Poaceae e Rubiaceae. As fisionomias savânicas foram mais ricas do que a florestal. A razão entre espécies arbustivo-arbóreas e herbáceo-subarbustivas foi de aproximadamente 2:1. Ana- lisamos a flora como um todo e seus componentes herbáceo-subarbustivo e arbustivo-arbóreo separadamente, comparando-os com outras áreas disjuntas de cerrado. Dessa comparação, obtivemos valores de similaridade (índice de Sørensen) de 0,47 a 0,81, que mostraram que a diversidade 3 foi maior no componente herbáceo- subarbustivo do que no componente arbustivo-arbóreo. Palavras-chave – cerrado, savana, fisionomia, florística. ABSTRACT – (Floristic composition of the cerrado in the Pé-de-Gigante Reserve (Santa Rita do Passa Quatro, southeastern Brazil)). We studied a 1225 ha area, composed mainly of cerrado, in Santa Rita do Passa Quatro, São Paulo State, southeastern Brazil (21°36-38’S, 47°36-39’W). In three cerrado physiognomies (campo cerrado – a wooded savanna, cerrado sensu stricto – a woodland, and cerradão – a tall woodland), we collected all vascular plants in reproductive stage, and identified them to species level. We found 360 species, representing 236 genera and 69 families. The richest families were: Asteraceae, Fabaceae, Poaceae, and Rubiaceae. The sa- vanna physiognomies were richer than the forest one. The ratio between herbaceous and woody species was approximately 2:1. We analysed the whole flora and its two components separately, woody and herbaceous, comparing them with other disjunct cerrado areas. We obtained similarity values (Sørensen index) from 0.47 to 0.81, which showed that the 3 diversity of the cerrado was higher in the herbaceous component than in the woody one. Key words – cerrado, savanna, physiognomy, floristics, woody: herbaceous ratio 1, 2 Depto. de Ecologia, Instituto de Biociências, Universidade de São Paulo, Caixa Postal 11.461, 05422-970, São Paulo, SP, Brasil. 1 Pós-Graduação em Ecologia ([email protected]). 2 Prof. Titular ([email protected]). 290 Batalha and Mantovani : Floristic composition of the cerrado in the pé-de-gigante reserve. Introduction Our aim was to carry out a floristic survey in a disjunct cerrado area, distinguishing its About 23% of the Brazilian territory (2 physiognomies. This survey intends to increase millions km2) were originally covered by cer- the knowledge of the cerrado flora, especially rado vegetation (Ratter et al. 1992). Its core area of the frequently neglected herbaceous compo- covers the Brazilian Central Highlands, in the nent, and to contribute to phytogeographical states of Minas Gerais, Mato Grosso, Mato studies. Grosso do Sul, Goiás, Tocantins, Maranhão, and Piauí (Mantovani & Martins 1993). Outlying Material and methods cerrado areas also occur in other states, as in São Paulo (Ratter et al. 1992). The Pé-de-Gigante Reserve is located in Santa The cerrado vegetation is characterized by Rita do Passa Quatro Municipality, São Paulo its wide physiognomic variation. According to State, southeastern Brazil, between 21°36-38’S Coutinho (1978), the cerrado goes from campo and 47°36-39’W, under a Cwag’ (Köppen 1948) limpo, a grassland, to cerradão, a woodland. The or B3B’3w (Thornthwaite & Mather 1955) climate intermediate physiognomies (campo sujo – a type, at 590 to 740m high, on Red-Yellow Latosol shrub savanna, campo cerrado – a wooded sa- (Pivello et al. 1998). Its name (“Pé-de-Gigante” vanna, and cerrado sensu stricto – a woodland) or “Giant’s foot”) was given due to the presence are considered ecotones. of a foot-shaped geomorphological formation in Accompanying the physiognomic variation, the Paulicéia Stream drainage basin (Fig. 1). The the cerrado vegetation presents a high floristic study area covers 1225ha, in which are found richness. Castro et al. (1999) compiled many mainly cerrado physiognomies: campo sujo floristic and phytosociological surveys carried (0.25% of the total area), campo cerrado (7.9%), out in cerrado areas and estimated the number cerrado sensu stricto (79.0%) and cerradão of vascular plant species in this vegetation type (11.1%). Other vegetation types are also present, ranging from 3,000 to 7,000. Mendonça et al. such as floodplain grassland, gallery forest and (1998) listed 6,429 species for the whole do- seasonal semideciduous forest. A more detailed main, including, besides the cerrado itself, oth- characterization of the study area can be found in er associated vegetation types, such as gallery Pivello et al. (1998, 1999a). forest, deciduous and semideciduous forest, and First, the reserve was mapped with remote floodplain grassland. sensing techniques, using a vegetation index that The cerrado vegetation has two distinct flo- measures the green biomass, with which the oc- ras, a woody one and an herbaceous one, which currence of cerrado regions was assigned (Biten- are antagonistic, because both are sun-loving court et al. 1997, Pivello et al. 1999a). We distin- (Coutinho 1978). The importance of the herba- guished the cerrado physiognomies following the ceous flora gradually decreases from the cam- “forest-ecotone-grassland” concept (Coutinho po limpo to the cerradão, while the importance 1978). Then, in each cerrado physiognomy, ex- of the woody flora increases in this direction cept the campo sujo due to its small extension, we (Coutinho 1978). Mantovani & Martins (1993) carried out floristic surveys in monthly field trips, compared some cerrado areas, and they found a each one with 23hr sampling effort, from Septem- species ratio of 1:2 to 1:3 between the woody ber 1995 to February 1997, when we collected all and the herbaceous floras. Castro et al. (1999) vascular plant species in reproductive phase. We emphasized the almost complete absence of lodgeal the collected exsicata in the herbarium of studies that sampled the herbaceous component, São Paulo Botanical Institute (SP). Plants in spite of its high richness. were classified in families according to the sys- Acta bot. bras. 15(3): 289-304. 2001 291 tem proposed by Judd et al. (1999). The species (Jongman et al. 1995) and Sørensen index as dis- were classified in life forms in accordance with tance measure (Magurran 1988). The results were Raunkiaer’s system, adapted by Mueller-Dombois compared in the same way with other floristic sur- & Ellenberg (1974). We considered the phanero- veys, in which similar methods were used (Man- phyte species as belonging to the woody compo- tovani & Martins 1993, Batalha et al. 1997). nent and the non-phanerophytes species as belong- ing to the herbaceous one. We calculated the flo- Results and Discussion ristic similarity among the different physiogno- mies at species level, grouping them in clusters, In the cerrado physiognomies (campo cer- using average-linking as agglomerative algorithm rado, cerrado sensu stricto, and cerradão), 360 Figure 1. Aerial photograph (1:40.000) of the Pé-de-Gigante Reserve, Santa Rita do Passa Quatro, São Paulo State, Brazil (21°36-38’S, 47°36-39’W). 292 Batalha and Mantovani : Floristic composition of the cerrado in the pé-de-gigante reserve. species were found, belonging to 236 genera and species (Pivello et al. 1999b). This situation 69 families (Tab. 1 and 2). The richest families occurs also in the Pé-de-Gigante Reserve, where were: Fabaceae, Asteraceae, Poaceae, Rubiace- African grasses, especially Melinis minutiflora ae, Bignoniaceae, Myrtaceae, Malpighiaceae, P. Beauv. and Brachiaria decumbens Stapf, are Malvaceae, and Apocynaceae, together account- spreading fast (Pivello et al. 1999c). ing for 57.8% of collected species (Fig. 2). A total of 272 species were found in the These families are also the most represen- campo cerrado; 308, in the cerrado sensu stric- tative ones in other cerrado areas, such as La- to; and 148, in the cerradão (Tab. 2). Following goa Santa (Warming 1892), Triângulo Mineiro the “forest-ecotone-grassland” concept (Coutin- (Goodland 1979), Brasília (Ratter 1980), Moji ho 1978), the ecotonal physiognomies are ex- Guaçu (Mantovani & Martins 1993), and Piras- pected to be richer, because they contain spe- sununga (Batalha et al. 1997). cies from both the herbaceous and the woody Of the total collected species, 16 (4.4%) are components. Indeed, the existing ecotonal phys- weeds that does not occur spontaneously in cer- iognomies in the Pé-de-Gigante Reserve, cam- rado sites (Mendonça et al. 1998). In this vege- po cerrado and cerrado sensu stricto, were rich- tation type, this is mainly a consequence of the er than one of the extremes, cerradão. The fragmentation and edge effect (Pivello et al. woody to herbaceous species ratio for all three 1998, 1999b). Mendonça et al. (1998) listed for physiognomies together (cerrado sensu lato) the whole Cerrado Domain 289 weedy species, was approximately 1:2 (Tab. 2). This ratio in- or 4.5% of its total flora, the same proportion creased from cerradão, in which the number of observed in the Pé-de-Gigante flora. Plant in- woody species was higher than those of herba- vasions are a major problem in cerrado frag- ceous species, to campo cerrado (Tab. 2). Once ments, occuring pratically in every one of them, again, this is expected according to the “forest- dominating in patches and outcompeting native ecotone-grassland” concept (Coutinho 1978), 16 14 12 10 8 6 4 Percentage of species 2 0 Fab Ast Poa Rub Big Mrt Mlp Mlv Apo Figure 2.