Examinando por Autor "Imbrozio Barbosa, Reinaldo"

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Environmental filters and biotic interactions drive species richness and composition in ecotone forests of the northern Brazilian Amazonia
(Museu Paraense Emílio Goeldi, 2021-09-07) Rodrigues Silva, Williamar; Costa Lima Pequeno, Pedro Aurélio; Sousa Farias, Hugo Leonardo; Ferreira Melo, Valdinar; Angulo Villacorta, Carlos Darwin; Silva Carvalho, Lidiany Camila; Oliveira Perdiz, Ricardo; Camurça Citó, Arthur; Imbrozio Barbosa, Reinaldo
The structure of tree communities in tropical forests depends on environmental filters and biotic interactions such as competition and facilitation. Many ecotone forests in Northern Amazonia are intriguingly populated by tree assemblages characterized by distinct abundances of a single species, Peltogyne gracilipes (Leguminosae). It is unclear whether this pattern solely reflects environmental filters or also antagonistic interactions among species with similar habitat requirements. The aim of this study was to determine the response of species richness and composition to environmental filters, and analyze the role of P. gracilipes in structuring tree communities in ecotone forest areas of the Northern Brazilian Amazonia. We sampled 129 permanent plots along a hydro-edaphi gradient. All arboreal individuals with stem diameter ≥10 cm were measured and identified. Multiple regressions were performed to test the effects of environmental filters, and abundance of P. gracilipes on the tree species richness and composition. Species richness and composition responded to the same filters which, in turn, affected species composition directly and indirectly, through the abundance of P. gracilipes. Our results indicate that both abiotic filters and biotic interactions shape the studied tree communities. P. gracilipes can be considered an indicator species of hydro-edaphic conditions, but also is itself a driver of tree community structure.
Pedoenvironments driving the monodominance of Peltogyne gracilipes (Leguminosae) in the Northern Amazon, Brazil
(Universidade Federal de Roraima, 2022-02-02) Angulo Villacorta, Carlos Darwin; Da Silva Carvalho, Lidiany Camila; Trindade Nascimiento, Marcelo; Imbrozio Barbosa, Reinaldo
Monodominance is unusual in the tropics when compared to the high diversity of tropical forests. Peltogyne gracilipes (Leguminosae) is a deciduous tree species that forms monodominant forests in the Brazilian Northern Amazon region. Initial research confirmed that P. gracilipes monodominance was associated with higher soil magnesium content, while recent studies have indicated a larger number of variables, suggesting a more complex hydro-edaphic habitat. As such, the present study aimed to describe the hydro-edaphic habitat (pedoenvironment) where P. gracilipes is monodominant. Edaphic and topographic variables (drainage proxy) were used in a forest inventory conducted in 129 sampling plots. Trees with a stem diameter greater than 10 cm were analyzed. Aboveground biomass was used as a descriptive variable of the different habitats in the study area. A total of 3041 individuals were sampled (298 P. gracilipes). Multivariate analysis demonstrated that the highest P. gracilipes abundance occurred in poorly drained (seasonal flooding) low-altitude habitats (<66 m), with high soil Fe+2 and Mg+2 concentrations. P. gracilipes monodominance in the study area is best described in habitats with more restricted hydro-edaphic conditions, where drainage is the primary factor and Fe+2 and Mg+2 are secondary agents resulting from the effect of seasonally drained soils. This study contributes to better understanding the environmental filters that characterize areas where P. gracilipes is more abundant, indicating that this species might potentially become monodominant in more restricted hydro-edaphic habitats in the Northern Amazon.