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271.
Peres CA Baider C Zuidema PA Wadt LH Kainer KA Gomes-Silva DA Salomão RP Simões LL Franciosi ER Cornejo Valverde F Gribel R Shepard GH Kanashiro M Coventry P Yu DW Watkinson AR Freckleton RP 《Science (New York, N.Y.)》2003,302(5653):2112-2114
A comparative analysis of 23 populations of the Brazil nut tree (Bertholletia excelsa) across the Brazilian, Peruvian, and Bolivian Amazon shows that the history and intensity of Brazil nut exploitation are major determinants of population size structure. Populations subjected to persistent levels of harvest lack juvenile trees less than 60 centimeters in diameter at breast height; only populations with a history of either light or recent exploitation contain large numbers of juvenile trees. A harvesting model confirms that intensive exploitation levels over the past century are such that juvenile recruitment is insufficient to maintain populations over the long term. Without management, intensively harvested populations will succumb to a process of senescence and demographic collapse, threatening this cornerstone of the Amazonian extractive economy. 相似文献
272.
Carvalho Ddo C Brigagão MR dos Santos MH de Paula FB Giusti-Paiva A Azevedo L 《Plant foods for human nutrition (Dordrecht, Netherlands)》2011,66(2):114-121
Differentiation between organic and conventional coffee has increased due to the growing demand and high consumption of healthy
foods that contain compounds with antioxidant potential, which have been associated with the reduction of chronic diseases.
We used organic and conventional coffee in powder 4% (w/w) and infusions 5%, 10% and 20% (w/v) incorporated in a commercial
diet to test in vivo. The levels of chlorogenic acid, caffeine and trigonelline were determined by high performance liquid chromatography. The
body weight, weight gain, food consumption, aberrant foci crypt, mucin depleted foci, stress biomarkers protein carbonyl and
malondialdehyde, biochemical parameters and behavior of the rats were compared between the experimental and control groups
within a framework of colon carcinogenesis. The organic coffee showed higher levels of chlorogenic acid, caffeine and trigonelline
than conventional, however, this difference did not significantly affect behavior. The infusions had an antioxidant effect,
reducing the levels of malondialdehyde; however, the biochemical parameters of the serum were not altered, and there was neither
induction nor prevention of preneoplasic lesions. 相似文献
273.
274.
Douglas Ticiani Crislei Larentis Débora Reis de Carvalho Ana Cristina Ribeiro Rosilene Luciana Delariva 《Ecology of Freshwater Fish》2023,32(1):147-165
Impoundments caused by dams are often responsible for intense changes in physical, chemical, geomorphological and hydrological characteristics of rivers, and are one of the main causes in global freshwater biodiversity declines. When these changes derive from multiple cascading dams, the cumulative effect can amplify, causing more pronounced consequences than each individual reservoir, which may affect, among other factors, the biotic and functional conditions of fish fauna. We aim to evaluate the impact of dam cascades on fish functional diversity by applying trait-based analysis. We evaluate the functional attributes (functional indices and community-weighted means of trait values) and environmental variables at 11 sites, which encompassed different segments affected by the hydroelectric plants (transition, reservoir, reduced discharge section and tributary) in the Antas River Basin dam cascade system located in southern Brazil. The spatial differences of the functional indices (richness, evenness, divergence, dispersion and diversity) as well as the weighted averages of each functional trait were tested through analysis of variance. The most affected functional characteristics were those related to habitat exploration by detritivorous species, especially the use of food resources and body shape, as well as the type of swimming movement. These traits were more representative at the most downstream site of the complex. Thus, our results suggest that the cascade of dams acts in the functional homogenisation of the ichthyofauna in the intermediate stretches, mainly reflecting physical changes in habitat. 相似文献