No abstract

The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher's alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between ∼ 40,000 and ∼ 53,000, i.e., at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as species-rich as the Neotropics, with both regions having a minimum of ∼ 19,000-25,000 tree species. Continental Africa is relatively depauperate with a minimum of ∼ 4,500-6,000 tree species. Very few species are shared among the African, American, and the Indo-Pacific regions. We provide a methodological framework for estimating species richness in trees that may help refine species richness estimates of tree-dependent taxa.

A new method is proposed for the extraction of morphometric characteristics of plant leaf structures. A sample of 10 species of the genus Passiflora (P. coriacea Juss., P. foetida L., P. miersii Mast., P. organensis Gardner, P. pohlii Mast., P. suberosa L., P. amethystina J.C. Mikan, P. caerulea L., P. gibertii N.E.Br., P. maliformis L.) was used in an experiment to test the method. This genus shows a wide range of leaf forms, but there are some species pairs or groups whose morphological similarity makes their correct identification difficult. The multiscale function of the Minkowski fractal dimension was applied to digital images of leaves to generate complexity measures of their internal (veins) and external (leaf outline) form. The results of the leaf characteristic extraction method, as well as its potential as the basis for an identification mechanism, are discussed for the 10 species. The method was very accurate in correctly differentiating among species, since no leaf was erroneously identified. A small number of leaves per species was sufficient for establishing a characteristic pattern for each of them, which constitutes an important advantage of the method in the recognition and classification procedure.Key words: image processing, fractal dimension, plant taxonomy, morphometry, Passiflora.

Este trabalho resume os dados de florística e fitossociologia de 11, das 14 parcelas de 1 ha, alocadas ao longo do gradiente altitudinal da Serra do Mar, São Paulo, Brasil. As parcelas começam na cota 10 m (Floresta de Restinga da Praia da Fazenda, município de Ubatuba) e estão distribuídas até a cota 1100 m (Floresta Ombrófila Densa Montana da Trilha do rio Itamambuca, município de São Luis do Paraitinga) abrangendo os Núcleos Picinguaba e Santa Virgínia do Parque Estadual da Serra do Mar. Na Restinga o solo é Neossolo Quartzarênico francamente arenoso, enquanto que na encosta o solo é um Cambisolo Háplico Distrófico argilo-arenoso, sendo que todas as parcelas apresentaram solo ácido (pH 3 - 4) com alta diluição de nutrientes e alta saturação de alumínio. Na Restinga e no sopé da encosta o clima é Tropical/Subtropical Úmido (Af/Cfa), sem estação seca, com precipitação média anual superior a 2.200 mm e temperatura média anual de 22 ºC. Subindo a encosta mantêm-se a média de precipitação, mas há um gradativo resfriamento, de forma que a 1.100 m o clima é Subtropical Úmido (Cfa/Cfb), sem estação seca, com temperatura média anual de 17 ºC. Destaca-se ainda que, quase diariamente, a parte superior da encosta, geralmente acima de 400 m, é coberta por uma densa neblina. Nas 14 parcelas foram marcados, medidos e amostrados 21.733 indivíduos com DAP > 4,8 cm, incluindo árvores, palmeiras e fetos arborescentes. O número médio de indivíduos amostrados nas 14 parcelas foi de 1.264 ind.ha-1 (± 218 EP de 95%). Dentro dos parâmetros considerados predominaram as árvores (71% FOD Montana a 90% na Restinga), seguidas de palmeiras (10% na Restinga a 25% na FOD Montana) e fetos arborescentes (0% na Restinga a 4% na FOD Montana). Neste aspecto destaca-se a FOD Terras Baixas Exploradas com apenas 1,8% de palmeiras e surpreendentes 10% de fetos arborescentes. O dossel é irregular, com altura variando de 7 a 9 m, raramente as árvores emergentes chegam a 18 m, e a irregularidade do dossel permite a entrada de luz suficiente para o desenvolvimento de centenas de espécies epífitas. Com exceção da FOD Montana, onde o número de mortos foi superior a 5% dos indivíduos amostrados, nas demais fitofisionomias este valor ficou abaixo de 2,5%. Nas 11 parcelas onde foi realizado o estudo florístico foram encontradas 562 espécies distribuídas em 195 gêneros e 68 famílias. Apenas sete espécies - Euterpe edulis Mart. (Arecaceae), Calyptranthes lucida Mart. ex DC. e Marlierea tomentosa Cambess (ambas Myrtaceae), Guapira opposita (Vell.) Reitz (Nyctaginaceae), Cupania oblongifolia Mart. (Sapindaceae) e as Urticaceae Cecropia glaziovii Snethl. e Coussapoa microcarpa (Schott) Rizzini - ocorreram da Floresta de Restinga à FOD Montana, enquanto outras 12 espécies só não ocorreram na Floresta de Restinga. As famílias com o maior número de espécies são Myrtaceae (133 spp), Fabaceae (47 spp), Rubiaceae (49) e Lauraceae (49) ao longo de todo gradiente da FOD e Monimiaceae (21) especificamente nas parcelas da FOD Montana. Em termos de número de indivíduos as famílias mais importantes foram Arecaceae, Rubiaceae, Myrtaceae, Sapotaceae, Lauraceae e na FOD Montana, Monimiaceae. Somente na parcela F, onde ocorreu exploração de madeira entre 1960 e 1985, a abundância de palmeiras foi substituída pelas Cyatheaceae. O gradiente estudado apresenta um pico da diversidade e riqueza nas altitudes intermediárias (300 a 400 m) ao longo da encosta (índice de Shannon-Weiner - H' - variando de 3,96 a 4,48 nats.indivíduo -1). Diversas explicações para este resultado são apresentadas neste trabalho, incluindo o fato dessas altitudes estarem nos limites das expansões e retrações das diferentes fitofisionomias da FOD Atlântica durante as flutuações climáticas do Pleistoceno. Os dados aqui apresentados demonstram a extraordinária riqueza de espécies arbóreas da Floresta Ombrófila Densa Atlântica dos Núcleos Picinguaba e Santa Virgínia do Parque Estadual da Serra do Mar, reforçando a importância de sua conservação ao longo de todo o gradiente altitudinal. A diversidade desta floresta justifica também o investimento de longo prazo, através de parcelas permanentes, para compreender sua dinâmica e funcionamento, bem como monitorar o impacto das mudanças climáticas nessa vegetação.

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The main objective of this study was to characterize the tree arboreal species composition and to compare secondary and mature forests of the Morro Grande Forest Reserve (Cotia, metropolitan region of São Paulo, Brazil). Based on this evaluation, we discuss the forest type classification and the conservation value of this Reserve. We used the point centered quarter method, sampling 2,400 trees in six different sites, three with secondary forests and three other ones with a predominance of mature forests. In each site, four blocks of 25 points were assessed, totalizing 100 points or 400 individuals. The blocks were 200 m apart from each other. Data were analyzed through cluster and Detrended Correspondence Analysis (DCA). Results showed differences among sites, essentially differentiating the secondary and mature sites. DCA and cluster analyses were particularly useful to detect characteristic species for these two main successsional stages. Among the 260 species observed, only 12 were sampled in the six sites. Richness and diversity were surprisingly high when compared with previous studies in the study region. The Shannon diversity values were among the highest in the state of São Paulo, with 4.75 nats/tree for the whole sampling, 4.25 nats/tree for the three secondary sites, and 4.54 nats/tree for the three mature sites. The studied forest may be essentially classified as "Dense Mountain Rain Forest" presenting species from the Araucaria mixed forest, and also from the semi-deciduous forest and Cerrado (woody savanna) region. Those results seem to confirm the hypothesis of a "high montane refuge" in drier climatic conditions in the past. The high richness and mixed composition of different floras highlighted the importance to preserve the Morro Grande forest.

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We investigated the patterns of growth and reproduction of the understory clonal palm Geonoma brevispatha based on the identification of post-germinative ontogenetic stages, over a 3-year period. Genets were monitored in 100 5 × 5 m plots and 100 2 × 2 m subplots, in a 1-ha area of swamp forest in São Paulo state, southeastern Brazil. Ramets pass through four ontogenetic stages (bifid-leafed juveniles, pinnatifid-leafed stemless immatures, stemmed nonreproductive virgins, and reproducers). Leaf size, leaf number, and leaf production rate increased during ontogeny, but diameter growth rate was higher among immatures. Stem length, number of nodes, and leaf rachis length were positively correlated across ontogenetic stages, but crown height was smaller than stem length in adult palms because of frequent leaning. Leaf number and sexual fecundity increased with ramet size, but declined in larger, senescent ramets. Clonal fecundity preceded sexual fecundity, and sexual and clonal fecundity increased continuously with genet size. No relationship was found between sexual and clonal fecundity. Growth and survival strategies of G. brevispatha were consistent with the patterns found in other tropical clonal palm species. Sexual fecundity and cloning seem to be two integrated processes favored by environmental conditions that also support the growth of existing ramets.Key words: stage-structured populations, ontogenetic stages, swamp forest, Brazil, Atlantic forest, senescence.