60 resultados para Plant distribution


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Balancing power production and environmental conservation can be problematic. The objective of this study was to investigate the abundance of marsh deer in the Paraná River Basin, above the Sergio Motta (Porto Primavera) Dam, before and after the impact of the dam closure. A fixed-wing, flat window aircraft was used to survey study transects. Observations were recorded based on the distance sampling line transect method, assuming that the detection probability decreases with increased distance. The abundance of marsh deer in the survey region prior to flooding was estimated to be 974 individuals (CV = 0.23). The overall abundance dropped from 974 to 444 (CV = 0.26) individuals after flooding, an overall reduction of 54%. This reduction can be attributed to the direct impact of the flooding process, but it was likely exacerbated by indirect effects, such as increased disease, hunting, and reduction in food availability. Prior to flooding, the marsh deer was distributed widely throughout the dam's catchment area; however, the marsh deer habitat was almost completely destroyed by the flooding process. This situation highlights the need to implement management strategies that ensure the survival of the remaining fragmented population.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Forty-five Brazilian populations of freshwater Audouinella were analysed using multivariate morphometrics. These populations were statistically related to seven type specimens. Five species are recognised on the basis of qualitative (plant colour and size, basal system type and branch angle) and quantitative (length and diameter of vegetative cells and monosporangia) characters. A. hermannii (syn. A. violacea) is characterised by a reddish colour, an irregular prostrate basal system, open branch angles (greater than or equal to 25 degrees) and small monosporangia (less than or equal to 15 mu m in diameter). A. macrospora (syn. A. chalybea var. brasiliensis) is distinguished from the other Brazilian species by having a bluish colour, a basal system composed of well-developed rhizoids, narrow branch angles (< 25 degrees) and large monosporangia (greater than or equal to 15 mu m in diameter). A. meiospora is microscopic and has a reddish colour, a basal system composed of creeping filaments, narrow branch angles and small monosporangia. A. pysmaea (syn. A. leibleinii) is characterised by being bluish, having an irregular prostrate basal system, narrow branch angles and small monosporangia. A, tenella is distinct from the other species by having a reddish colour, an irregular prostrate basal system, open branch angles, small monosporangia and small vegetative cells (less than or equal to 6 mu m in diameter). An identification key and revised descriptions and synonyms are presented for the five species. A. meiospora and A. tenella are reported for the first time for Brazil. A. macrospora and A. pygmaea were the most widespread species and occurred in tropical and subtropical regions. A. meiospora was found at two sites in a tropical rainforest region, whereas A. hermannii and A. tenella were found at only one site. Selected physical and chemical environmental data (temperature, specific conductance, current velocity, turbidity, pH and dissolved oxygen) are presented for most species.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The relationships between the spatial and temporal variations in the abundance of the shrimp Nematopalaemon schmitti and water temperature, salinity, and texture and organic-matter content of the sediment, were analysed in Ubatumirim, Ubatuba and Mar Virado bays on the northern coast of São Paulo, Brazil. Sampling was carried out monthly, from January 1998 through December 1999, from a shrimp boat equipped with double-rig nets, along six transects in each bay. In total, 2 116 specimens of N. schmitti were caught. Their distribution differed among bays, transects and seasons (ANOVA, p < 0.05). Highest total abundance was found in areas of high organicmatter content, in substrate composed mainly of very fine sand and silt and clay, and during winter and autumn. Although multiple regression analysis showed no significant relationship (p > 0.05), observations suggest that water tempera ture, sediment texture, organic-matter content, and the presence of biodetritus and plant fragments, provided favourable environmental conditions for the establishment of N. schmitti in the region.

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Palicourea rigida H.B.K. (Rubiaceae), a medicinal species commonly known as douradinha, has wide distribution across ecosystems in Central and South America. This species exhibits seed dormancy delaying germination until optimal conditions for seedling growth and development are in place. While dormancy ensures species survival, it also presents a technical problem for developing P. rigida’s plant production program. Thus, the objective of this study was to investigate if secondary metabolites present in seeds influence the seed dormancy of P. rigida. Mature fruits were harvested from the native habitat, in the savanna region of the State of Minas Gerais during February 2009, 2010 and 2011. The content of phenolic compounds in the seed of P. rigida was measured, and the allelopathic effects were assessed using the germination of lettuces as model to detect phytotoxicity. The P. rigida seeds geminated at rates varying between 7% and 31% with a Seed Germination Index (SGI) of 0.09. Data suggest that the phenolic compounds present in the seeds may be responsible for seed dormancy.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)