859 resultados para Social and spatial dynamics


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Questions: Grasslands are usually neglected as potential carbon stocks, partially due to the lack of studies on biomass and carbon dynamics in tropical grasslands. What is the importance of Brazilian tropical wet grasslands as carbon sinks? Does fire frequency and season affect biomass and carbon allocation in Brazilian wet grasslands? Location: Wet grasslands, tropical savanna, Jalapão, Tocantins, northern Brazil. Methods: We determined biomass above- and below-ground, estimated carbon stocks in biennially burned plots (B2) and plots excluded from fire for 4 yr (B4). Moreover, we determined biomass in both rainy and dry seasons. Samples were 0.25 m × 0.25 m × 0.2 m (eight samples per treatment, applying a nested design, total of 48 samples). The biomass was classified in above-ground graminoids, forbs and dead matter, and below-ground roots and other below-ground organs. We used ANOVA to compare variables between treatments and seasons. Results: More than 40% of the total biomass and carbon stocks were located below-ground, mostly in roots. A high proportion of dead biomass (B4) was found in the above-ground material, probably due to low decomposition rates and consequent accumulation over the years. Although these grasslands do not experience water stress, we found significant evidence of resource re-allocation from below-ground organs to the above-ground biomass in the rainy season. Conclusions: We found more dead biomass in the rainy season, probably due to low decomposition rates, which can increase fire risk in these grasslands during the following dry season. These tropical wet grasslands stored high amounts of carbon (621 to 716 g C.m-2), mostly in the roots. Thus, policymakers should consider tropical grasslands as potential carbon stocks, since they are one of the most threatened and unprotected ecosystems in Brazil. © 2012 International Association for Vegetation Science.

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São Paulo State, in Brazil, is getting increasingly crowded, like in other third world countries around the world, so should give great importance to city development. This work considered the phenomenon of closed neighbourhoods (CN) as an important factor to city planning, papers report many impacts of this model of neighbourhoods in other countries, but in Brazil its impacts are not yet well listed in the literature. The aim of this work was to determine indicators to achieve the social and environmental performances and verify their applicability on three different closed neighbourhoods in São Paulo state, Brazil. The indicators were condensed on indexes: water management, waste management, energy and emissions, legal compliance, environment and buildings, risk management, health and education and governance. The preliminary results indicated several social and environmental problems in all indexes. © 2013 WIT Press.

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Summary Lists the meetings and conferences for which ECLAC/CDCC provided substantive servicing. Provides details on non-recurrent publications produced by the ECLAC/CDCC secretariat. These include: an investigative study on women and the micro-enterprise sector in the Bahamas, and poverty eradication and female headed household (FHH); in the Caribbean. Finally, provides a list of the instances in which ECLAC/CDCC has provided advice and technical assistance and notes the governments and countries which were beneficiaries of such assistance.

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Entrega un resumen del estudio de factibilidad para la creacion del Consejo del Caribe para el Desarrollo Economico y Social.

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The correlation between vegetation patterns (species distribution and richness) and altitudinal variation has been widely reported for tropical forests, thereby providing theoretical basis for biodiversity conservation. However, this relationship may have been oversimplified, as many other factors may influence vegetation patterns, such as disturbances, topography and geographic distance. Considering these other factors, our primary question was: is there a vegetation pattern associated with substantial altitudinal variation (10-1,093 m a.s.l.) in the Atlantic Rainforest-a top hotspot for biodiversity conservation-and, if so, what are the main factors driving this pattern? We addressed this question by sampling 11 1-ha plots, applying multivariate methods, correlations and variance partitioning. The Restinga (forest on sandbanks along the coastal plains of Brazil) and a lowland area that was selectively logged 40 years ago were floristically isolated from the other plots. The maximum species richness (>200 spp. per hectare) occurred at approximately 350 m a.s.l. (submontane forest). Gaps, multiple stemmed trees, average elevation and the standard deviation of the slope significantly affected the vegetation pattern. Spatial proximity also influenced the vegetation pattern as a structuring environmental variable or via dispersal constraints. Our results clarify, for the first time, the key variables that drive species distribution and richness across a large altitudinal range within the Atlantic Rainforest. © 2013 Springer Science+Business Media Dordrecht.