Navegando por Assunto "Amazon forest"

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Acesso aberto (Open Access)
Exposição das florestas da Amazônia à velocidade das mudanças climáticas
(Universidade Federal do Pará, 2021-02-19) AMARAL, Calil Torres; VIEIRA, Ima Célia Guimarães; http://lattes.cnpq.br/3761418169454490; https://orcid.org/0000-0003-1233-318X; SOUZA, Everaldo Barreiros de; http://lattes.cnpq.br/6257794694839685; https://orcid.org/0000-0001-6045-0984
Climate change is occurring at an accelerated rate and, as a result, species must produce adaptive responses to survive. The redistribution of biodiversity is one of the most anticipated effects for tropical species, as they have narrow thermal niches that make them less able to adapt to new environmental conditions. Evidence has already been observed in many Amazonian taxonomic groups, however, it remains uncertain whether the species will be able to follow up future climate changes. The amazon is among the global regions most exposed to long distances to climates analogs and to the emergence of new climate conditions. Along with this, the advance of deforestation may restrict the amount of habitats favorable to the distribution of species in the future, in addition to impairing connectivity to areas with a similar climate. Protected areas (PAs) can contribute to the redistribution of Amazonian biodiversity as climate havens, representing an important connectivity strategy between present and future climates, but they may be insufficient, given the speed of climate change promoted by human activities. Climate velocities represent a method to quantify the rate at which species must change their distribution in order to preserve their current climatic adaptation characteristics. In this work, the speed of climate change in the Amazon biome is investigated, based on climatic analogues between the present and the future, from the directions of advancement (present-future) and retreat (future-present), emphasizing the network of PAs in the region. The median climatic velocity of these areas was compared with that of unprotected areas (UAs), in order to verify the effectiveness of PAs in maintaining favorable climatic conditions for the adaptation of species in future climate change scenarios. In addition, the climatic refuges of the Amazon biome were identified and the impact of deforestation on these areas was quantified. To achieve these objectives, data from annual air temperature and precipitation averages with a spatial resolution of 10 km were used, in order to describe the current (1970-2000) and future (2041-2060) mesoclimates. The results show that the effects of the recoil speed will be greater in magnitude and spatial extension. Despite this, the network of PAs will be less exposed to the impacts of the recoil speed than UAs - emphasizing the importance of these areas as a tool in conservation. In contrast, for impacts related to the speed of advancement, the PA network will be slightly more exposed than PAs - indicating that the current spatial layout of the PA network is still not the most suitable for minimizing the impacts of climate change. It was also found that climatic refuges occupy only 7% of the Amazon biome, and are distributed along the edges of the biogeographic limit. In just 12 years, deforestation has caused a loss of more than 5% of these areas. In view of this scenario, it is necessary to further limit the loss of forests and include climate refuges in the conservation agendas of the Amazon, in order to enhance the conservation of the biota of Amazonian forests under climate change scenarios.
Acesso aberto (Open Access)
Exposição das florestas da Amazônia à velocidade das mudanças climáticas
(Universidade Federal do Pará, 2021-03-19) AMARAL, Calil Torres; VIEIRA, Ima Célia Guimarães; http://lattes.cnpq.br/3761418169454490; https://orcid.org/0000-0003-1233-318X; SOUZA, Everaldo Barreiros de; http://lattes.cnpq.br/6257794694839685; https://orcid.org/0000-0001-6045-0984
Climate change is occurring at an accelerated rate and, as a result, species must produce adaptive responses to survive. The redistribution of biodiversity is one of the most anticipated effects for tropical species, as they have narrow thermal niches that make them less able to adapt to new environmental conditions. Evidence has already been observed in many Amazonian taxonomic groups, however, it remains uncertain whether the species will be able to follow up future climate changes. The amazon is among the global regions most exposed to long distances to climates analogs and to the emergence of new climate conditions. Along with this, the advance of deforestation may restrict the amount of habitats favorable to the distribution of species in the future, in addition to impairing connectivity to areas with a similar climate. Protected areas (PAs) can contribute to the redistribution of Amazonian biodiversity as climate havens, representing an important connectivity strategy between present and future climates, but they may be insufficient, given the speed of climate change promoted by human activities. Climate velocities represent a method to quantify the rate at which species must change their distribution in order to preserve their current climatic adaptation characteristics. In this work, the speed of climate change in the Amazon biome is investigated, based on climatic analogues between the present and the future, from the directions of advancement (present-future) and retreat (future-present), emphasizing the network of PAs in the region. The median climatic velocity of these areas was compared with that of unprotected areas (UAs), in order to verify the effectiveness of PAs in maintaining favorable climatic conditions for the adaptation of species in future climate change scenarios. In addition, the climatic refuges of the Amazon biome were identified and the impact of deforestation on these areas was quantified. To achieve these objectives, data from annual air temperature and precipitation averages with a spatial resolution of 10 km were used, in order to describe the current (1970-2000) and future (2041-2060) mesoclimates. The results show that the effects of the recoil speed will be greater in magnitude and spatial extension. Despite this, the network of PAs will be less exposed to the impacts of the recoil speed than UAs - emphasizing the importance of these areas as a tool in conservation. In contrast, for impacts related to the speed of advancement, the PA network will be slightly more exposed than PAs - indicating that the current spatial layout of the PA network is still not the most suitable for minimizing the impacts of climate change. It was also found that climatic refuges occupy only 7% of the Amazon biome, and are distributed along the edges of the biogeographic limit. In just 12 years, deforestation has caused a loss of more than 5% of these areas. In view of this scenario, it is necessary to further limit the loss of forests and include climate refuges in the conservation agendas of the Amazon, in order to enhance the conservation of the biota of Amazonian forests under climate change scenarios.
Acesso aberto (Open Access)
Modelagem ambiental na floresta nacional do Jamanxim-PA: proposta de cenário futuro
(Universidade Federal do Pará, 2022-02-21) GAMA, Luana Helena Oliveira Monteiro; ALMEIDA, Arlete Silva de; http://lattes.cnpq.br/1511094180664778
Protected areas were created essentially for the conservation of fauna and flora. Analyzing its socio-environmental dynamics becomes a challenge, and at the same time contributes to the understanding of the landscape. The present study aims to model future scenarios from remote sensing and geoprocessing techniques in the National Forest (FLONA) of Jamanxim-PA, based on the land use classification of the years 2013 and 2020. Analyze the independent variables through of Artificial Intelligence. Apply the DINAMICA EGO model using the transition method to simulate deforestation trajectories up to 2030, based on the dependent variables (land cover and use 2013 and 2020) and independent variables (altimetry, slope, distance to roads, distance to settlements and distance to hydrography. The high rates of deforestation within the limits of conservation units, lead to large environmental losses over time. According to INPE, the state of Pará presented the highest forest loss of the Brazilian Amazon states in 2019, a total of 3,862 km2 , with an increase rate of 41% when compared to 2018. Through the mathematical model it is possible to analyze “Where” will be deforested; “When” will it be deforested and what deforestation rates will be; and “How”, what will be the spatial representation of the new areas of modification, that is, how the deforestation process will be based on the dynamic cover and use of the land and the elements that make up the landscape, such as the variations independent activities, it is possible to carry out future projections of deforestation in the FLONA do Jamanxim. Theories of authors representing different currents of Geography are approached to conceptualize space, landscape and dynamic modeling. In Physical Geography, one starts from Bertrand's concepts. For Quantitative Geography, Waldo Tobler was used as a basis. The discussion of Critical Geography is based on the works of Milton Santos. And Soares-Filho for spatial dynamic modeling. The methodology was divided into three main phases: 1- Processing of satellite images, using the supervised classification method through the Maximum Likelihood algorithm; 2- Processing of independent variables; 3- Stage considered the main part of the study, which consists of spatial modeling in DINAMICA EGO. As a result of the analysis of land cover and use, it was observed that there was a reduction in the area of 112.51 km² (0.87%) of primary forest, and an increase in the mosaic class of occupations (deforestation) with an area of 393.53 km², equivalent to 3% of deforested area. The main activities observed were: forest exploitation and mining. There is also a deforestation pattern classified as geometric and regular, with economic activities, such as agriculture, and mainly medium to large-scale grain and livestock monocultures, and an intermediate stage of occupation. The independent variables assume Bertrand's GTP model to observe landscape dynamics. It was observed that 0.28% of the primary forest was converted to deforestation. That is, from 2013 to 2020 deforestation is occurring at a net rate of 28% per year. And there is a high probability of transition from primary forest to a mosaic of occupations, and from forest exploitation to a mosaic of occupations to the north and south of the FLONA do Jamanxim, areas that may be associated with the implementation of roads (BR-163), and to the PDS Brasília and Vale do Jamanxim Project settlements, which consequently can impact the resilience of the landscape. Based on modeling and analysis of future scenarios, it appears that there may be a loss of 198.79 km² (1.52%) of primary forest, and a considerable increase in deforestation of 155.20 km² by 2030. The mapping of this study, it can support public policy actions by analyzing the impact of laws and identifying priority areas for government action in FLONA do Jamanxim. Based on the spatial modeling, together with the command, control and monitoring plans, it is possible to guide the socio-environmental, economic and cultural development in this UC, for the maintenance and conservation of natural assets.
Acesso aberto (Open Access)
Palm community transitions along a topographic gradient from floodplain to terra firme in the eastern Amazon
(Instituto Nacional de Pesquisas da Amazônia, 2015-03) SALM, Rodolfo Aureliano; PRATES, Anderson Sousa; SIMÕES, Nadson Ressyé; FEDER, Lisa
Palms show clear niche segregation patterns along topographic gradients in tropical forests, with some species associated to terra firme and others to seasonally flooded areas. The aim of this study was to quantitatively describe the fine-scale spatial variation within a palm community, tracking the changes in species' abundance along environmental gradients associated with a perennial stream the eastern Amazon. The study of palm communities was based on 60 forest plots in which all adult palms were counted. We found a total of 566 palms in a community containing 11 species. Furthermore, we found a significant separation in the palm community between seasonally-flooded and terra firme forests. We found a gradient with various densities of the three most abundant palm species within the first 100 m away from the flooded area. Other species were located exclusively in the terra firme forest. The abundance of the six most common species were distributed in relation to humidity gradients from floodplains to terra firme, with palm distribution from the most flood-tolerant to the least flood-tolerant palm species as follows: Euterpe oleracea, Attalea phalerata and Socratea exorrhiza (species with floodplain affinity), Astrocaryum gynacanthum, Astrocaryum aculeatum, Attalea maripa (species with terra firme affinity).