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The Brazilian Amazon supplies the world with several forests ecosystem services, many of which are essential to sustain human life on earth. Nevertheless, the Amazon is threatened by deforestation and degradation implying in reductions on the provision of these. According to economic theory, as ecosystem services are positive externalities and public goods, agents do not take into consideration the costs and benefits of their consumption and production of ecosystem services into their economic decisions. To address this problem payment for ecosystem services – PES – emerged, aiming to provide a source of income to the poor people living in forest areas, stimulating them not to deforest, and making agents who are indebted with the nature pay for their overconsumption of ecosystem services. There is still controversy about possible impacts of the instrument. This article accesses the potentials of PES to contribute to sustainable development in the Brazilian Amazon using the three goals related to sustainable development proposed by the ecological economics theory: efficient allocation, fair distribution, and sustainable scale. The study shows that PES as a pure market approach is unlikely to solve neither the scale nor the distribution problems. Therefore, for PES to achieve sustainable development, markets for ecosystem services should first be constrained by a maximum sustainable scale. Then, measures should ensure fair distribution in second place. Only after these questions have been tackled, it is desirable that agents interact in the ecosystem services markets to lead to an efficient allocation of resources.
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The hydrophysical properties of the prevalent Humic Latosols (organic matter rich and charcoal stained soils) were related to structural sustainability under loading. Intact cores collected at the Ap, AB, Bw horizons were used for hydrophysical characterization. Precompression stresses at 10 suctions were obtained to estimate the load bearing capacities. We observed the dominance of kaolinite with some occurrences of gibbsite and hydroxy-interlayered vermiculite in the clay mineralogy. The high organic matter content in the Ap horizon favours crumb structure with the structural unit presenting high porosity and water retention. The structure of the AB and Bw horizons was, however, granular with structural units having low porosity. Possible influence of earlier incidences of fire enhanced the organic matter and carbon content in the soil reducing down the profile from 42.5 g kg-1 at the Ap to 16.4 g kg-1 at the Bw horizon. The C/N ratio increased from 14 at the Ap to 17 at the Bw, and air capacity increased from 18.1% at Ap to 32.0% at Bw. Precompression stress values were: 100.6±40.7 kPa at Ap, 117.4±44.6 kPa at AB, and 116.1±58.9 kPa at Bw. Load bearing capacities at the AB and Bw horizons were homogenous.
A survey of the capacity to endure desiccation was obtained for several Brazilian rock outcrop plants. Seedlings, leaves and entire plants were subjected to dehydration. After dehydration, survival was observed as the ability to recover growth, chlorophyll content and/or by the absence of leakage of leaft contents. A total of 30 species growing in rock outcroppings in southeastern Brazil showed some ability to undergo extreme dehydration. The species belong to the cryptogams Polypodiaceae, Pteridaceae, Schizaeaceae and Selaginellaceae and to the angiosperms Cyperaceae, Poaceae and Velloziaceae. All cryptogams were homeochlorophyllous. Among the angiosperms Microchloa indica (Poaceae) was the only species with the capacity to retain chlorophyll content during dehydration. All species showed some evidence of desiccation tolerance similar to that previously reported for tolerant angiosperms in Africa. The data suggest that rock outcroppings from the southeastern and central regions of Brazil give support to typical vegetation in which a great number of species exhibit a desiccation-tolerant comportment.
Eichhornia azurea (Schwartz) Kunth is one of the most abundant species of aquatic macrophyte in the Upper Paraná River floodplain, and ephemeropteran nymphs frequently inhabit this plant. The objective of this study was to analyze the distribution of ephemeropteran nymphs associated with three sections (apical, intermediate, and basal) of E. azurea in two floodplain lakes of the Upper Paraná River as well as to establish the relation of this distribution to biotic and abiotic factors. The samplings of apical, intermediate and basal sections of E. azurea were carried out monthly from October 1997 to October 1998. Higher concentration of dissolved oxygen may contribute to greater density of nymphs on the apical plant segments near the water surface. Callibaetes willineri was the most abundant taxon, occurring on the apical and intermediate plant sections whereas Campsu- rus spp. were recorded on the basal and intermediate sections of the plant, near the sediment and, mainly during high water. Lower dissolved oxygen concentrations near the lake bottom during the high water phase might suggest that during this phase the nymphs of Campsurus violaceus also migrate to E. azurea roots. It was found that changes in water level influenced the variation of the abundance of nymphs. Other genera, such as Tricorythodes and Leptohyphes, were recorded during the high water phase, when river water enters the lakes and their shores are flooded.
Parasite assemblages of marine fishes include an important number of larval stages of helminth parasite species that use fish as intermediate or as paratenic hosts. In previous comparative studies, larval helminths have typically been lumped with other endoparasites, and there has been therefore no study of the biodiversity and relative abundance of larval helminths and of the factors that may influence them. Here, we performed a comparative analysis across 50 species of teleost fishes from the coast of Brazil; we evaluated the effects of several host traits (body size, social behaviour, feeding habits, preference for benthic or pelagic habitats, depth range, ability to enter brackish waters and geographical distribution) on the richness and abundance of larval helminths. Among all the potential correlates of larval helminth infection investigated in this study, only two were significant when controlling for host phylogenetic influences: Host body length was correlated positively with larval helminth abundance, and fish species with a restricted geographical distribution (Atlantic coast of Brazil mainly) had greater larval helminth abundance than their relatives with a broader (whole Atlantic or cosmopolitan) distribution. Different results were obtained if no correction was made for host phylogeny: Using species values as independent statistical observations, some additional host features also appeared associated with larval helminth species richness or abundance. The results of these analyses indicate that fish phylogeny matters. Apparently, some lineages of fish harbour more larval helminths (more species and/or more individuals) than others merely because of historical reasons (i.e., ancient associations between certain parasite taxa and fish taxa) and not really because of their present ecological characteristics.
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