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2 resultados encontrados para: AUTOR: Valle Ferreira, Leandro
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1.
Artículo
*En hemeroteca, SIBE-San Cristóbal
Effects of flooding duration on species richness, floristic composition and forest structure in river margin habitat in Amazonian blackwater floodplain forests: implications for future design of protected areas
Valle Ferreira, Leandro ;
Contenido en: Biodiversity and Conservation Vol. 9, no. 1 (January 2000), p. 1-14 ISSN: 0960-3115
Bibliotecas: San Cristóbal
Cerrar
SIBE San Cristóbal
B8617 (Disponible)
Disponibles para prestamo: 1
Nota: En hemeroteca, SIBE-San Cristóbal
Resumen en: Español |
Resumen en español

Rivers in central Amazonia experience annual water-level fluctuations of up to 14 m, flooding vast areas of adjacent forest for periods ranging from a few to 270 days per year. At different sites, variation in the duration and type of flooding results in a mosaic of habitats that includes lakes, grasslands, forests, and streams. To study the effects of flood duration on plant species richness and floristic composition, two river margin sites were surveyed on the rivers Jaú and Tarumã-Mirim. Both areas are seasonally flooded by blackwaters, and plots were made at different topographic levels (lower, middle and upper slopes). All woody plants with DBH > 5cm were inventoried in five 10 × 40 m plots in each of the three topographic levels, which varied in length of flood duration and mean water level. Plant species richness did not vary significantly between topographic levels, but species composition varied substantially. At both study sites, the species composition exhibited distinctive distribution patterns with respect to the three topographic levels and river site. Differences in the distribution of dominant species in both sites probably relate to the ability of species to withstand seasonal flooding, although other edaphic factors associated with the topographic levels may also be important, especially for less-dominant, locally rare, and habitat generalist species. Species composition overlap among topographic levels at the two sites was highly variable ranging from 15% to 43%. Knowledge about the complex pattern of species composition and distributions between and among topographic levels and river sites is important for the preservation of the diverse flora of the blackwater forests and for the creation of future conservation management plans and design of protected areas in this ecosystem that will maintain the biodiversity


2.
Artículo
*En hemeroteca, SIBE-San Cristóbal
Species richness and floristic composition in four hectares in the Jaú National Park in upland forests in Central Amazonia
Valle Ferreira, Leandro ; Prance, Ghillean T. (coaut.) ;
Contenido en: Biodiversity and Conservation Vol. 7, no. 10 (october 1998), p. 1349-1364 ISSN: 0960-3115
Bibliotecas: San Cristóbal
Cerrar
SIBE San Cristóbal
B8632 (Disponible)
Disponibles para prestamo: 1
Nota: En hemeroteca, SIBE-San Cristóbal
Resumen en: Español |
Resumen en español

Four hectares were inventoried for all trees with diameter at breast height (DBH) of 10cm or greater in a terra firme forest 200km Northeast of Manaus, Central Amazonia. The number of species varied from 137 to 168, the number of individuals from 639 to 713, total basal area from 32.8 to 40.2 and total biomass from 405 to 560 tons per hectare. The majority of trees, 90%, had a DBH between 10 and 30 cm. Leguminosae, Lauraceae, Sapotaceae, Chrysobalanaceae and Moraceae were the most rich families (number of species) in all sampled hectares. The most abundant families in all sampled hectares (number of trees) were Leguminosae, Burseraceae, Myristicaceae, Moraceae and Chrysobalanaceae. The most dominant families in all sampled hectares (basal area and biomass) were Leguminosae, Lecythidaceae, Chrysobalanaceae, Bombacaceae and Moraceae. Similarity indexes at family level varied from 67 to 86% between the four hectares sampled. Alexa grandiflora (Leguminosae) was the most abundant species in the hectares one and three, while Scleronema micranthum (Bombacaceae), and Oenocarpus bacaba (Palmae) were the most abundant species in hectares two and four

S. micranthum was the most dominant species (basal area) in hectares one and two, while Bertholletia excelsa (Lecythidaceae) and Goupia glabra (Celastraceae) were the most dominant species in hectares three and four. S. micranthum (Bombacaceae), Buchenavia sp. 2 (Combretaceae), B. excelsa (Lecythidaceae) Couepia obovata (Chrysobalanaceae) were the most dominant species (biomass) in hectares one to four, respectively. Similarity indexes at species level varied from 26 to 44% between the four sampled hectares. This inventory is compared with previous studies and it was found that, in our study area, there was a greater proportion of trees of 60cm diameter or more and consequently a considerably higher total basal area. It is concluded that there are still an inadequate number of inventories of Amazonian terra firme forests to elucidate the major floristic pattern a both regional and local levels. Since the area is a mosaic of distinct floristic communities it is essential to obtain further standardized inventory data in order to set adequate conservation policies for the region