Navegando por Assunto "Mata ciliar"

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Acesso aberto (Open Access)
Características sedimentares fluviais associadas ao grau de preservação da mata Ciliar - Rio Urumajó, Nordeste Paraense
(Instituto Nacional de Pesquisas da Amazônia, 2009-03) BRITO, Roney Nonato Reis de; ASP NETO, Nils Edvin; BEASLEY, Colin Robert; SANTOS, Helane Súzia Silva dos
Rivers are the main ways of sediment transport from inland to the coastal zone and oceans. Despite direct influence of climate, the vegetation coverage plays a central role in liquid and solid fluvial discharge. In this context, the present work aimed to study the fluvial sedimentology of the Urumajó River (Pará, Brazil) in relation to the preservation state of riparian vegetation. Sediment samples were collected at five sites (A to E), including a five-sample transversal profile at each site. The sites were distributed from the source to the estuarine area. The characteristics and preservation state of the riparian vegetation were analyzed at each site as well. The collected sediments were submitted to grain size analysis, where mean grain size, median, asymmetry, selection and kurtosis were obtained. The results made it possible to recognize the regular characteristics (sites A and C), which included median sand as the main sediment class and well-sorted and approximate symmetric grain size distribution, directly related to the well-preserved riparian vegetation at sites A and C. On the other hand, sites B, D and E showed substantial differences in relation to the regular pattern. This fact could be associated to the vegetation degradation at those sites, resulting in margin erosion. Furthermore, at site E, reflexes of tide influence on the sediment characteristics could be observed, subsidizing the estuary delimitation.
Acesso aberto (Open Access)
Feeding ecology of Auchenipterichthys longimanus (Siluriformes: Auchenipteridae) in a riparian flooded forest of Eastern Amazonia, Brazil
(2011) FREITAS, Tiago Magalhães da Silva; ALMEIDA, Vitor Hudson da Consolação; VALENTE, Roberta de Melo; MONTAG, Luciano Fogaça de Assis
Feeding habits of the midnight catfish Auchenipterichthys longimanus collected in rivers of the Caxiuanã National Forest (Eastern Amazonia, Brazil) were investigated through the different hydrological periods (dry, filing, flood and drawdown). A total of 589 specimens were collected throughout seven samplings between July 2008 and July 2009, of which 74 were young males, 177 adult males, 89 young females and 249 adult females. The diet composition (Alimentary index – Ai%) was analyzed by a non-metric multidimensional scaling (nMDS) and by the analysis of similarity (ANOSIM), which included 37 items grouped into nine categories (Aquatic insects, Other aquatic invertebrates, Arthropods fragment, Fish, Plant fragment, Seeds, Terrestrial insects, Other terrestrial invertebrates, and Terrestrial vertebrates). We also calculated the niche breadth (Levins index) and the repletion index (RI%). Differences in the diet composition between hydrological seasons were registered, primarily on diet composition between dry and flood season, but changes related with sex and maturity were not observed. The midnight catfish showed more specialists feeder habit in the flood period (March 2009) and more generalist habits in the dry season (November 2008). The amount of food eaten by A. longimanus based on repletion index (RI%), did not differ significantly from sex and maturity. However, we evidenced differences in RI% when comparing the studied months. These results provide important biological information about the trophic ecology of auchenipterids fish. In view of the higher occurrence of allochthonous items, this research also underpins the importance of riparian forests as critical environments in the maintenance and conservation of wild populations of fish in the Amazon basin.
Acesso aberto (Open Access)
“Proteger a mata para o rio não secar”: análise da recuperação de matas ciliares realizada por agricultores familiares às margens do rio Itabocal, Irituia – PA
(Universidade Federal do Pará, 2020-03-06) COSTA, Diego de Mendonça; ALVES, Lívia de Freitas Navegantes; http://lattes.cnpq.br/1337509239539346
On the municipalities of Pará’s Northeast mesoregion, family farmers have been standing out by establishing experiences with forest recovering on their properties. Based on that context, it was aimed to understand how forest recovering of riparian forest has been implemented on their agricultural establishments, considering their importance to the environment and the relation built between those areas, the Amazonian rural populations and their water resources. Hence, the research supports on the principles of systemic approach and of interdisciplinarity. The region of Itabocal, rural area of the Irituia’s municipality, located on the Northeast of Pará, was chosen as sample. In the first paper the processes of forest recovering found on the area’s riparian forest were characterized through a typology developed by field research. Altogether, three main types of recovering were identified, being enrichment of regenerating forest, natural regeneration and agroforestry systems. In the second paper, the socio-productive trajectories that took the farmers to decide on riparian forest recover were investigated, through a space-time analysis. After analyzing how factors that were extern to their agriculture establishments and how those that were intern of their systems influenced them through the years, it was understood that the recover of the areas was mostly caused by the concern with the maintenance of quality, flow and biota of the region’s biggest stream, Itabocal river. With the knowledge of Itabocal river’s importance to the local population, the third paper focused on the impacts suffered on it and the proposition of solutions to control them, based on the socio-spatial analysis built with the farmers. The deforestation of riparian forest, encouraged mainly by landowners, was noteworthy as the most frequent impact. It was also noticed that the river’s management is established on a non-institutional way on the region, generated by the family farmers’ efforts towards its maintenance. The results showed that the Itabocal’s family farmers follow a trend towards the forest recovering and have a well-defined perception over the problems caused by the deforestation of riparian forest. The main obstacles noticed for the recovering of those areas are related to a) the inefficiency of local public power in inspecting and stimulating them, either by proposing legal instruments of incentive or by including the region’s inhabitants on the decision making process relative to environmental conservation; and b) on the absence of certain groups’ environmental consciousness, like landowners, that insist on the riparian forest predatory exploitation. It was accomplished that the relevance of riparian forest recover is tied to the relation that the studied population have with the water.