249 research outputs found
Carbon dynamics in aboveground coarse wood biomass of wetland forests in the northern Pantanal, Brazil
International audienceThis is the first estimation on carbon dynamics in the aboveground coarse wood biomass (AGWB) of wetland forests in the Pantanal, located in Central Southern America. In four 1-ha plots in stands characterized by the pioneer species Vochysia divergens Pohl (Vochysiaceae) forest inventories (trees ?10 cm diameter at breast height, DBH) have been performed and converted to predictions of AGWB by five different allometric models using two or three predicting parameters (DBH, tree height, wood density). Best prediction has been achieved using allometric equations with three independent variables. Carbon stocks (50% of AGWB) vary from 7.4 to 100.9 Mg C ha?1 between the four stands. Carbon sequestration differs 0.50?4.24 Mg C ha?1 yr?1 estimated by two growth models derived from tree-ring analysis describing the relationships between age and DBH for V. divergens and other tree species. We find a close correlation between estimated tree age and C-stock, C-sequestration and C-turnover (mean residence of C in AGWB)
Florística e estrutura da comunidade arbórea de duas áreas de Cerrado Sentido Restrito no norte de Minas Gerais
Florística, fitossociologia e diversidade da vegetação arbórea nas matas de galeria do Parque Nacional de Sete Cidades (PNSC), Piauí, Brasil
From individuals to communities : how singleton invasive pine saplings lead to biodiversity change in the Brazilian Cerrado hotspot
This work was funded by the Brazilian Ciência sem Fronteiras/Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) (1091/13-1), European Research Council (AdG BioTIME 250189and PoC BioCHANGE 727440), the Royal Society and the Brazilian Conselho Nacional de Desenvolvimento Científico e Tecnológico/CNPq (307839/2014-1).Questions: How do newly established species interact with existing assemblage members to alter local biodiversity? This question is especially topical given growing concerns about increased temporal turnover levels relative to background rates. Pine (Pinus spp.), a major invasive taxon in the southern hemisphere, is progressively dominating remaining fragments of the Brazilian savanna (Cerrado), a biodiversity hostpot. Because the Cerrado's diversity is linked to habitat heterogeneity we argue that the impact of these invasive singleton pines will be mediated by differences in local habitat structure. Here we use isolated invasive pines Pinus elliottii in the Cerrado as a study system to test the prediciton that changes in the diversity of native communities, in the presence of newly established exotic individuals, will be greatest in the dominant vegetation layer of a habitat. Location: Itirapina Ecological Station, southeast of Brazil. Methods: We used a stratified random survey in 5x5m pairs of plots invaded by a single pine individual each matched by control uninvaded plots; both shrub and grass vegetation layers were sampled in both habitats. In total, 300 plots were sampled, 114 in the shrub‐dominated campo sujo and 186 in the grass‐dominated campo úmido. Results: Over four hundred plant species were recorded. In both habitats, we detect marked shifts in species richness of the dominant vegetation layer. In line with our prediction, the nature of these changes is mediated by local habitat structure. We find significantly reduced species richness in the shrub layer of the shrub‐dominated habitat but elevated species richness in the grass layer of the grass‐dominated habitat in invaded sites (v. control). In the grass layer of campo úmido, pine initially decreases dominance thus allowing more species to colonize the plots. Conclusions: The shape of the diversity v. establishment time relationship is layer dependent, with a significant relationship between dominance/evenness and pine size in the grass layer but no relationship in the shrub layer. Our results show that, though complex, the consequences for local biodiversity of non‐native species establishment are not haphazard, and thus contribute to the understanding of species coexistence.PostprintPeer reviewe
Temporal dynamics of the shrub and herbaceous layer of an area of moist grassland in Alto Paraíso de Goiás, Brazil
Este trabalho avaliou a dinâmica estrutural e fl orística de uma comunidade de espécies herbáceo-arbustivas
de uma área de campo limpo úmido em Alto Paraíso de Goiás, o primeiro inventário realizado em 2000 (T0) e o
segundo em 2007 (T1). A diversidade de Shannon entre os períodos foi comparada pelo teste-t de Hutcheson e a
similaridade fl orística, pelo índice de similaridade de Chao-Sørensen. As relações fl orísticas e a cobertura, entre os
períodos e as linhas, foram avaliadas por meio de análises de correspondência retifi cada (DCA). Foram amostradas
98 espécies, 88 no T0 e 67 no T1, sendo 31 exclusivas do T0 e 10 do T1. A diversidade fl orística na comunidade
foi elevada nos dois períodos, porém diferente entre esses (t = 7,12; p < 0,001), devido a variação no número e
cobertura das espécies. A similaridade entre os dois inventários foi alta (Chao-Sørensen ± IC = 0,841 ± 0,074). A
ordenação por DCA indicou relações entre a composição fl orística e a cobertura com o gradiente de umidade e
de matéria orgânica no solo identifi cados em T0. Houve modifi cações nas linhas em zonas sazonais, as quais se
tornaram mais semelhantes às linhas constantemente saturadas por água. Em um intervalo de sete anos o campo
limpo úmido apresentou mudanças na composição fl orística e, principalmente na estrutura devido o aumento da
cobertura de espécies perenes, cespitosas e entouceiradas, que foram favorecidas pela maior umidade no solo em
resposta à elevação da pluviosidade da região. __________________________________________________________________________________________ ABSTRACTTh is study evaluated the fl oristic and structural dynamics of a community of herbaceous-shrub species
in an area of moist grassland in Alto Paraíso de Goiás. Th e fi rst inventory was undertaken in 2000 (T0) and the
second in 2007 (T1). Shannon’s diversity between the periods was compared by Hutchesons´s t-test, and the
fl oristic similarity by the Chao-Sørensen similarity index. Floristic composition and cover, between periods and
lines, were evaluated by detrended correspondence analysis (DCA). We sampled 98 species, 88 at T0 and 67 at T1;
31 were unique to T0 and 10 to T1. Floristic diversity in the community was high in both periods, but diff erent
between them (t = 7.12, p <0.001), due to variation in species number and coverage. Similarity between the two
surveys was high (Chao-Sørensen CI = ± 0.841 ± 0.074). Th e DCA ordination indicated relationships between the
fl oristic composition and cover with a gradient of moisture and organic matter in the soil identifi ed in T0. Th ere
were changes in the lines in the seasonal zones, which became more similar in those constantly saturated with
water. During an interval of seven years the moist grassland showed changes in fl oristic composition and mainly
in structure due to increased cover of the clumped tussock perennial species, which were favored by higher soil
moisture due to high rainfall in the region
Avaliação temporal da regeneração natural em uma floresta estacional semidecídua secundária, em Pirenópolis, Goiás
Componente arbóreo, estrutura fitossociológica e relações ambientais em um remanescente de cerradão, em Curvelo - MG
Fitossociologia e análise comparativa da composição florística do cerrado da flora de Paraopeba-MG
Comparison between canopy trees and arboreal lower strata of urban semideciduous seasonal forest in Araguari - MG
Estrutura fitossociológica de um fragmento natural de floresta inundável em área de Campo Sujo, Lagoa da Confusão, Tocantins
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