Pedro Higuchi

Comparação florística de florestas inundáveis das regiões Sudeste e Sul do Brasil

This study evaluated the variation of tree species composition of 35 wetland forest areas in Southeast and South Brazil. The analysis of the floristic composition was based on a floristic checklist containing 602 species of 23 alluvial forests (seasonally inundated) and 12 swamp forests (permanently waterlogged). The species were classified, using a c2 test, according to the habitat preference in: 1) swamp forest species, e.g. Magnolia ovata (A. St.-Hil.) Spreng., Dendropanax cuneatus (DC.) Decne & Planch. and Calophyllum brasiliense Cambess.; 2) alluvial forest species, e.g. Sebastiania commersoniana (Baill.) L.B. Sm. & Downs, Ocotea pulchella Mart. and Sorocea bonplandii (Baill.) W. Burger et al. and 3) non preferential species, e.g. Luehea divaricata Mart. & Zucc., Syagrus romanzoffiana (Cham.) Glassman and Copaifera langsdorffii Desf. Multivariate gradient analysis (Detrended Correspondence Analysis) showed higher clustering of swamp forest areas than aluvial forest areas, indicating close florist similarity in the first group. The results indicated that the environmental heterogeneity associated to different flood regimes is determinant in defining the phytogeographic patterns of wetland forest areas.

Relações florísticas e fitossociologia de uma Floresta Ombrófila Mista Montana Secundária em Lages, Santa Catarina

O presente estudo teve como objetivos caracterizar a estrutura fitossociologica de um fragmento de floresta secundaria em Lages, SC, contextualizar a composicao floristica do componente arboreo do fragmento em relacao a outros remanescentes da regiao do Planalto Sul-Catarinense e avaliar a influencia de variaveis geograficas e climaticas sobre os padroes observados. O levantamento da composicao floristica e estrutural da vegetacao arborea, do fragmento estudado, foi conduzido em 25 parcelas de 400 m2, onde todos os individuos arboreos com DAP (diâmetro medido a altura do peito) ≥ 5 cm foram medidos e identificados. Para o estudo das relacoes floristicas entre o fragmento estudado e outros remanescentes da regiao foi utilizada a Arvore de Regressao Multivariada, que utilizou matrizes floristicas de especies arboreas de presenca e ausencia e de variaveis geograficas e climaticas de cada remanescente. Foram encontradas 87 especies, distribuidas em 36 familias botânicas. As especies de maior valor de importância no fragmento estudado foram Araucaria angustifolia (Bertol.) Kuntze e Podocarpus lambertii Klotzsch. A distribuicao diametrica da comunidade demonstrou padrao proximo ao J invertido e as populacoes tiveram padroes de distribuicao diferenciados. Foram descriminados tres agrupamentos floristicos associados a sazonalidade termica e a temperatura media anual. O presente fragmento esteve agrupado a outras areas de sazonalidade termica maior ou igual a 3,053°C.

Floristic composition and phytogeography of the tree component of Araucaria Forest fragments in southern Brazil

The present study examined the floristic composition of three fragments of Araucaria Forest (AF) in the Planalto Catarinense region of southern Brazil as well as the floristic contextualization of these areas in relation to other remnant AF sites. Three AF fragments at different altitudes were analyzed in the municipalities of Campos Novos, Lages, and Painel. Fifty 200 m2 plots were examined in each fragment and all of the trees with CBH (circumference at breast height) > 15.7 cm were identified. In order to floristically contextualize the study fragments, comparisons were made with other remnant AF sites by way of dendrograms and NMDS (Non-metric multidimensional scaling). Environmental and spatial variables were plotted on the diagram produced by the NMDS to evaluate their influence on the floristic patterns encountered. The forest fragments studied demonstrated high floristic heterogeneity, indicating that AFs cannot be considered homogeneous formations and they could be classified into 3 phytogeographical categories: i) high altitude areas influenced by cloud cover/fog, including the Painel region; ii) areas of lesser altitude and greater mean annual temperatures situated in the Parana River basin, and iii) areas situated in the Parana and Upper-Uruguay river basins and the smaller basins draining directly into the southern Atlantic, near Campos Novos and Lages. The environmental variables most highly correlated with species substitutions among the sites were altitude, mean annual temperature, and the mean temperature of the most humid trimester.

Dinâmica da comunidade arbórea em um fragmento de floresta estacional semidecidual montana em Lavras, Minas Gerais, em diferentes classes de solos

In order to analyze the existence of structural changes and the influence of different soils classes on tree community dynamics rates, a fragment of tropical montane seasonal semi-deciduous forest (8,7 ha) in SE Brazil was studied in a 5 years period (2000-2005). Data were collected in 47, 20 × 20 m, plots arranged in two 80 m distant transect, crossing the study area toward its widest length. In 2000, were surveyed all individuals with DBH > 5 cm. Species botanical identification were provided and diameters at breast height (DBH) were collected for each tree individual. In 2005, all dead trees were recorded, the surviving trees were remeasured and the recruits were measured and identified (DBH > 5 cm). Mortality, recruitments, basal area loss and gain rates were calculated for each plot, for the total area and for each soil class (Nitosols, Oxysols and Cambisols). The overall pattern in the fragment indicated reduction in number of individuals

COMPOSIÇÃO FLORÍSTICA DA REGENERAÇÃO NATURAL DE ESPÉCIES ARBÓREAS AO LONGO DE OITO ANOS EM UM FRAGMENTO DE FLORESTA ESTACIONAL SEMIDECIDUAL, EM VIÇOSA, MG 1

The floristic composition of the natural regeneration in a secondary Seasonal Semideciduous Forest fragment in the Atlantic Forest domain, Southeastern Brazil, was studied in the years 1992, 1995 and 2000. The sampling unit sizes were 0.5x10m, 0.5x20m and 1x20m, respectively, for plant size class 1 (height up to 1 m), class 2 (height from 1 to 3 m) and class 3 (height > 3m and DBH < 5cm). A total of 4,149 individuals were sampled over the inventory period, comprising 42 families and 160 species, being 11.7 % pioneer, 62.1 % early secondary, and 26.2 % late secondary species. Family number did not change and number of species increased with time. Fabaceae, Myrtaceae, Rubiaceae and Lauraceae were the predominant families. Species ingrowth was higher than mortality. Shannon-Weaver diversity index was significantly lower

Tree community floristic and structure of alluvial forest fragments in São Sebastião da Bela Vista, Minas Gerais, Brazil

Fragments of alluvial forest in the South of Minas Gerais, Brazil, were studied in order to assess the vegetation structure, tree diversity and the most influential environmental variables on vegetation variations. The environment and vegetation data (dbh ³ 5 cm) were collected in 54, 20 × 10 m, permanents plots allocated in a riverine forest and in five fragments of alluvial forests. In the plots, the survey totalled 2,064 tree individuals, distributed in 51 species. The canonical correspondence analysis detected a tree composition gradient in the first axis, related to Mg, organic matter and H + Al soil content, sand and clay percentage and soil water table level. The CCA second axis was associated with canopy coverage and soil silte percentage. Theses variables caused a plot group formation related to species distribution.

Dispersão, distribuição espacial e estratificação vertical da comunidade arbórea em um fragmento florestal no Planalto Catarinense

RESUMO – Este estudo teve como objetivo identificar as estrategias de dispersao de propagulos, a distribuicao espacial e a estratificacao vertical de especies arboreas em um fragmento de Floresta Ombrofila Mista em Lages, SC. Para amostragem da vegetacao arborea, foram alocadas 25 parcelas de 400 m² (20 m x 20 m) e todos os individuos arboreos dentro das parcelas com diâmetro a altura do peito (DAP, medido a 1,30 m do solo) maior ou igual a 5 cm foram identificados e tiveram sua altura estimada. Para complementar a lista floristica, foram feitos caminhamentos aleatorios no fragmento objetivando identificar especies arboreas nao amostradas nas parcelas. As especies foram classificadas segundo: i) a sua sindrome de dispersao em zoocorica, anemocorica ou autocorica; ii) o padrao de distribuicao espacial dos individuos, considerando-se a distribuicao aleatoria, agregada e uniforme; iii) a posicao no estrato vertical da floresta, como sendo dos estratos superior, intermediario ou inferior. Do total de 87 especies amostradas, 80,5% foram classificadas como zoocoricas, 16,1% como anemocoricas e 3,4% como autocoricas. Verificou-se a predominância de especies com distribuicao espacial aleatoria e pertencente ao estrato superior, com altura superior ou igual a 12,45 m. Os resultados indicam a importância da fauna silvestre para a manutencao do funcionamento ecologico do fragmento estudado, uma vez que a maior parte das especies sao zoocoricas. O conhecimento desses atributos das populacoes arboreas pode subsidiar estrategias de conservacao e manejo de fragmentos florestais na regiao, uma vez que permite conhecer melhor a ecologia das especies.

Spatial patterns of a tropical tree species growing under an eucalyptus plantation in South-East Brazil

The objectives of this study were to evaluate the influence of propagules source and the implication of tree size class on the spatial pattern of Xylopia brasiliensis Spreng. individuals growing under the canopy of an experimental plantation of eucalyptus. To this end, all individuals of Xylopia brasiliensis with diameter at soil height (dsh) > 1 cm were mapped in the understory of a 3.16 ha Eucalyptus spp. and Corymbia spp. plantation, located in the municipality of Lavras, SE Brazil. The largest nearby mature tree of X. brasiliensis was considered as the propagules source. Linear regressions were used to assess the influence of the distance of propagules source on the population parameters (density, basal area and height). The spatial pattern of trees was assessed through the Ripley K function. The overall pattern showed that the propagules source distance had strong influence over spatial distribution of trees, mainly the small ones, indicating that the closer the distance from the propagules source, the higher the tree density and the lower the mean tree height. The population showed different spatial distribution patterns according to the spatial scale and diameter class considered. While small trees tended to be aggregated up to around 80 m, the largest individuals were randomly distributed in the area. A plausible explanation for observed patterns might be limited seed rain and intra-population competition.

Spatial Pattern and Fine-Scale Genetic Structure Indicating Recent Colonization of the Palm Euterpe edulis in a Brazilian Atlantic Forest Fragment

Rainforests worldwide are subject to increasing amounts of external pressure and degradation that dissect continuous species distributions into small and isolated fragments (Whitmore 1997). This spatial isolation and reduction of natural populations negatively affects the reproductive success of many tropical plants (Fuchs et al. 2003; Quesada et al. 2004). A reduction in the number of reproductive individuals in a population represents a decrease in the number of pollen/ovary donors and in the quantity of pollen deposited (Aizen and Feinsinger 1994). This may be accompanied by a decrease in the abundance of pollinators and selection for self-compatibility (Stephenson et al. 2000). Subsequently, such impacts can lead to

INVASÃO POR ESPÉCIES ARBÓREAS EXÓTICAS EM REMANESCENTES FLORESTAIS NO PLANALTO SUL CATARINENSE

This study evaluated the invasion by exotic tree species in two Mixed Ombrophilous Forest (FOM) fragments (F1 and F2) in Lages, SC. A total of 25 plots were allocated in each fragment, distributed in five transects, 20x100 m, perpendicular to the edges and, at least, 100 m apart from each other, where the adult (dbh - diameter at breast height > 5 cm) and the regenerative (dbh 10 cm) component individuals were evaluated. These were identified and measured (circumference and height). For each component and fragment, the biological invasion index (BII) was determined. The relation between BII and the distance from the edge was evaluated by simple linear regressions. The grouping among exotic and native species was analyzed through Spearman correlation and clusters. A total of 3,701 individuals distributed in 105 species were sampled, being five invasive species. In F1 a relative low value of BII (0.05 and 0.54) occurred, with Pinus taeda L. as the most expressive species in the invasion, and it was grouped with native pioneers species. The BIIs in F2 were elevated (0.61 and 1.96), mainly due to the expressive participation of Ligustrum lucidum W.T. Aiton., grouped with typical species of FOM. No relation between the distance from the edges and the intensity of the invasion were observed. The results demonstrated that the fragments showed different biological invasion patterns that were determined by the nature of surrounding matrix and the ecological characteristics of the invasive species.