Navegando por Assunto "Efeito de borda"

Agora exibindo 1 - 4 de 4

Acesso aberto (Open Access)
Edge effects and the impact of wildfires on populations of small non-volant mammals in the forest-savanna transition zone in Southern Amazonia
(2012) FREITAS, Tiago Magalhães da Silva; ALMEIDA, Vitor Hudson da Consolação; VALENTE, Roberta de Melo; MONTAG, Luciano Fogaça de Assis
The impact of fire and edge effects on the community of small non-volant mammals was investigated in transitional Amazon forest within a matrix of soybean plantations. The animals were live trapped on 24 line transects, of which 16 were distributed in unburned areas and 8 in a burned area. A total of 11 species was recorded, including six rodents and five marsupials. The abundance and richness of small mammals appeared to decrease in burned areas, although this impact appeared to mask edge effects. In the absence of fire impacts, a positive relationship was found between mammal abundance and the distance from the forest edge. The impact of the edge effect on the diversity of small mammals appears to be influenced by the type of anthropogenic matrix and the ecological characteristics of the different species.
Desconhecido
O efeito da fragmentação insular na paisagem e comunidade arbórea em ilhas na Amazônia
(Universidade Federal do Pará, 2013) BORGES, Cézar Augusto Reis da Fonseca; FERREIRA, Leandro Valle; http://lattes.cnpq.br/8103998556619871
The construction of hydroelectric plants has been a new vector of forest fragmentation on the globe, especially in the Amazon, which has several dams under construction currently planned beyond. The training provides hydroelectric reservoirs in fragmented landscapes, with the creation of artificial islands (fragments), which have the peculiarity of being surrounded by an array tougher for most species, different fragments of land, having a direct effect on reducing biodiversity. This study aimed to evaluate the insular landscape of Lake Tucuruí, by quantifying landscape structure, as a basis for conservation implications. Concomitantly, we assessed the effects of fragmentation on the island tree community, through the structure of the landscape and edge effects, both have been one of the most ecological processes impacting on biodiversity in fragmented landscapes. The results indicated the spatial arrangement may be an approach used for conservation mechanisms in dams, but should consider specific aspects of the islands. In turn, the vegetation is still not responding to the current landscape structure, being in a phase of extinction debt, and the edge effect the main factor for the formation of plant communities.
Desconhecido
Estudo da comunidade de pequenos mamíferos não-voadores, sob efeito do fogo e da borda, em área de floresta de transição Amazônia-Cerrado, Querência, MT
(Universidade Federal do Pará, 2008-10-10) SANTOS, Paulo Guilherme Pinheiro dos; OLIVEIRA, Ana Cristina Mendes de; http://lattes.cnpq.br/1199691414821581
The deforestation of the Amazon, caused by farming and agribusiness activities in the northern state of Mato Grosso, has committed Transition Forests Amazon-Savanna, before the biodiversity of these areas is known by researchers. The fauna of small non-flying mammals is part of the little-known groups in the region, and may be suffering impacts of human activities, primarily effect of fire, used for cleaning of pastures and deforestation for the soybean plantations. This study characterized the diversity of small mammals not flying in an area of Amazon forest-savannah transition in the northern state of Mato Grosso and investigated the effect of fire and the effect of edge on this group of fauna. Two areas of 150 hectares were sampled, a preserved and another under impact of fire, with 183 traps of the type live-trap for three years in two season (dry and rainy seasons). The method used was the capture-mark-recapture. The sampling effort was 23,424-traps night. 390 individuals were captured with a successfully capture of 1.66%. A total of 11 species were caught, 6 rodents and 5 marsupials. Hylaeamys megacephalus was the most abundant species. The diversity of small mammals in the study area was more related to the Savanna than Amazon. In relation to fire, the species richness was not statistically different, but the abundance was significantly higher in transects located in an area without fire. Two distinct groups of transects were characteristic depending on the presence or absence of fire based on the composition of small mammals. The abundance of Hylaeamys megacephalus was significantly higher in transects that suffered no impact from fire. Regarding the effect of edge in Area 2, despite the richness of species was not significantly different, the abundance was significantly higher regarding distance from the border. Already in Area 1, nor richness nor abundance was statistically different regarding distance from the edge. This fact could be masked by both the direct and indirect effect of experimental fire on small mammals. When considered together fire and distance from the border, the relationship between them became clearer, since all transects sampled under effect of the fire had minor abundances. The population size of Hylaemys megacephalus was calculated over five seasons (dry and wet) in the area without influence of fire, and the rainy season of 2006 was statistically different peak and the other that growth can be explained by the “Alle effect”. There was no statistically significant differences in the structure of the community of small non-flying mammals between the dry and rainy seasons. This work contributed to the search of mammal knowledge at this region threatened by human pressures.
Desconhecido
Vulnerabilidade ao fogo de florestas intactas e degradadas na região de Santarém - Pará
(Universidade Federal do Pará, 2012-08-31) COSTA, Carla Daniele Furtado da; PARRY, Luke Thomas Wyn; http://lattes.cnpq.br/3567943056179690; VIEIRA, Ima Célia Guimarães; http://lattes.cnpq.br/3761418169454490
The Amazon is constituted today as the largest tropical rain forest remnant and continuous world and home to the largest diversity of plants and animals of all the Earth's biomes, and is critical to maintaining biodiversity. The region has undergone significant changes in recent decades, changes that are resulting mainly from changes in the landscape / vegetation cover, driven by population growth and inappropriate management practices of land, the result of deforestation, fires, changes in agricultural activities, livestock, farm logging, colonization programs, opening of roads and problems landowners. Among these factors, burning and forest fires becomes the most critical problem for the region, for fire management by farmers in most cases is done improperly, escaping control and causing economic damage, social and ecological. Forests that have burned since become more susceptible to new fires, as they become more flammable due to the change in canopy structure, dynamics of relative humidity, air temperature and fine fuel on the forest floor. Thus, this study aimed to investigate the diurnal patterns of flammability of intact and degraded forests in the region of Santarém - PA, area of major changes in land use pattern, with intense agriculture and farming, the region also presents significant number outbreaks of fire. It was observed that intact forests in the region are significantly less flammable than the degraded forests, and edges of degraded forests are more flammable than inside, supported by data on the dynamics of relative humidity and air temperature, humidity and rate of litter opening the canopy. These data were associated with socioeconomic data through interviews, in order to learn how farmers manage the fire, where the results showed that the training of fire management significantly influence the adoption of best practices in use of fire, for example, do not put fire in time critical (between 11 and 15 hours for the study area), making steel, burn against the wind, waiting for the first rain, among others. The size of the property does not significantly influence the proper use of fire, but small farmers are the ones who use it in their productive activities, since this constitutes the cheapest way to clean and prepare the land. In this sense, this paper aims to show the need for investment in research on the flammability of forests, improvement of the analysis of satellites associated with field research as a way to soften and perhaps solve the problem of fires in the Amazon, and contribute to adoption of a policy of encouraging the reduction of burning by farmers, coupled with the use of fire training, access to information technologies and alternatives to fire management.