Desmatamento na Amazônia: dinâmica, impactos e controle

Fearnside, Philip M.

doi:10.1590/s0044-59672006000300018

Cited by 187 publications

(162 citation statements)

References 24 publications

(22 reference statements)

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“…Drastic reductions in rainfall occurred in the Brazilian Amazon in 2005, when the water level of some of the large rivers of the basin dropped by up to 6 cm per day, drying floodplain lakes and creating problems for riverine populations that depend on water courses for transportation and for obtaining water and food (Fearnside, 2006;Marengo, 2007;Marengo et al, 2010;Tomasella et al, 2010). In contrast, in 2009, the Amazon basin was affected by extraordinarily strong rainfalls, which raised the water level of its rivers to a magnitude and duration rarely observed in the region, again causing economic and social damage to the human populations residing there (Marengo et al, 2011a(Marengo et al, , 2012.…”

Section: Introductionmentioning

confidence: 99%

Possible impacts of climate change on wetlands and its biota in the Brazilian Amazon

Barros

Albernaz

2014

Braz. J. Biol.

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Wetlands cover approximately 6% of the Earth´s surface. They are frequently found at the interface between terrestrial and aquatic ecosystems and are strongly dependent on the water cycle. For this reason, wetlands are extremely vulnerable to the effects of climate change. Mangroves and floodplain ecosystems are some of the most important environments for the Amazonian population, as a source of proteins and income, and are thus the types of wetlands chosen for this review. Some of the main consequences that can be predicted from climate change for wetlands are modifications in hydrological regimes, which can cause intense droughts or inundations. A possible reduction in rainfall can cause a decrease of the areas of mangroves and floodplains, with a consequent decline in their species numbers. Conversely, an increase in rainfall would probably cause the substitution of plant species, which would not be able to survive under new conditions for a long period. An elevation in water temperature on the floodplains would cause an increase in frequency and duration of hypoxic or anoxic episodes, which might further lead to a reduction in growth rates or the reproductive success of many species. In mangroves, an increase in water temperature would influence the sea level, causing losses of these environments through coastal erosion processes. Therefore, climate change will likely cause the loss of, or reduction in, Amazonian wetlands and will challenge the adaptability of species, composition and distribution, which will probably have consequences for the human population that depend on them.Keywords: global warming, wetlands, mangrove, floodplains, Amazonia. Possíveis impactos das mudanças climáticas em áreas úmidase sua biota na Amazônia brasileira ResumoAs áreas úmidas cobrem aproximadamente 6% da superfície da terra e são frequentemente encontradas na interface entre ecossistemas terrestres e aquáticos e fortemente dependentes do ciclo da água. Por esta razão são extremamente vulneráveis aos efeitos das alterações do clima. Os ecossistemas de manguezais e várzeas são muito importantes para os seres humanos da Amazônia, porque são de onde eles extraem algumas das principais fontes de proteínas e renda, e, por isso, foram os dois tipos de áreas úmidas escolhidos para esse estudo. Entre as principais consequências das mudanças climáticas previstas para esses ambientes estão as alterações nos regimes hidrológicos, que podem causar grandes secas ou inundações. A possível redução das chuvas pode causar a diminuição das áreas de mangue e várzea, provocando um rápido declínio de suas espécies. Por outro lado, o aumento das chuvas teria como provável consequência a substituição de espécies de plantas, que não seriam capazes de sobreviver sob as novas condições por um longo período de tempo. As principais consequências do aumento da temperatura da água entre as áreas úmidas seria que nas várzeas este parâmetro aumentaria a frequência ou duração dos episódios hipóxicos e/ou anóxicos, podendo causar a redução da taxa de...

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Section: Introductionmentioning

confidence: 99%

Possible impacts of climate change on wetlands and its biota in the Brazilian Amazon

Barros

Albernaz

2014

Braz. J. Biol.

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“…Além disso, pesquisas indicam que o desmatamento leva à perda dos serviços ambientais, que têm um valor maior que os usos pouco sustentáveis que substituem a floresta. Estes serviços incluem a manutenção da biodiversidade, da ciclagem de água e dos estoques de carbono que evitam o agravamento do efeito estufa (Fearnside, 2006).…”

Section: Introductionunclassified

Atributos químicos, físico-hídricos e mineralogia da fração argila em solos do Baixo Amazonas: Serra de Parintins

et al. 2010

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RESUMOEstudos sobre os atributos dos solos amazônicos geram informações para compor um levantamento atual sobre suas condições frente às várias formas de alterações que estão sujeitos. O objetivo deste trabalho foi descrever e avaliar a evolução química, físico-hídrica, bem como a mineralogia de Latossolos no Baixo Amazonas como forma de entender as variações desses atributos em diferentes coberturas vegetais. Coletaram-se amostras deformadas e indeformadas para análises físicas, químicas, mineralógicas e hídricas, em dois pontos de uma topossequência na Serra de Parintins: platô e vertente, sendo três perfis de solo em cada posição. Os resultados obtidos demonstraram que a floresta predominante sobre os perfis do topo e vertente promove condições físicas e hídricas adequadas para uma boa agregação, maior intensidade de poros grandes, maior condutividade hidráulica saturada (Ko) e melhor retenção hídrica dos solos. Fato semelhante ocorrendo com as áreas de capoeira, apresentando boa permeabilidade, porosidade e retenção de água no solo. O acúmulo de carbono é maior dos perfis da vertente, decrescendo em profundidade, relacionando-se diretamente com Ko e com o sistema radicular. A análise mineralógica da fração argila indicou a caulinita como argilomineral predominante, seguido pelos minerais gibbsita, goethita, quartzo e anatásio, não havendo variações ao longo da paisagem. A Serra de Parintins possui um solo pobre em nutrientes, ácido, com textura média a muito argilosa com acúmulo de plintita nos horizontes subsuperficiais, evitando o fenômeno de terras caídas. Um gradiente elevado de umidade volumétrica é observado nos horizontes subsuperficiais, havendo mais água retida, quando comparado com horizontes superficiais.PALAVRAS-CHAVE: Serra de Parintins, solos da Amazônia, condutividade hidráulica, retenção de água Chemical, physical and hydric attributes and mineralogy of clay fractions in soils of lower Amazon: Serra de Parintins ABSTRACTThe latest studies of attributes of soil of the Amazonian ecosystems provide information to make up a survey on these soil conditions in the face of several forms of changes they are submitted. This work aimed to describe and evaluate physical and hydric evolution as well oxisol mineralogy in lower Amazon in order to comprehend variations of these attributes in different vegetative covers. Deformed and non-deformed samples were collected for physical, chemical, hydric and mineralogical analyses, respectively in two points of a topographic sequence in Serra de Parintins: plateau and watershed, being showed three profiles of soil in each position. The results showed that predominant forest of the plateau and watershed profiles provide proper physical and hydric conditions for a good aggregation, higher intensity of large pores, larger saturated hydraulic conductivity (Ko) and better hydric retention of soils. Similar fact occurs in secondary forest, presenting such areas good permeability, porosity and water retention in soil. Carbon accumulation is higher in watershed profiles,...

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“…9 These burnings are responsible for signifi cant emissions of aerosol particles into the atmosphere, having both direct and indirect effects on the climate and the functioning of the Amazonian ecosystem. 3 The population's health is signifi cantly affected, especially in the region of the deforestation arc.…”

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confidence: 99%

Aerossois de queimadas e doencas respiratorias em criancas, Manaus, Brasil

et al. 2013

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OBJECTIVE:To investigate the effects of fi ne particulate matter emitted through biomass burning on hospitalizations for respiratory diseases in children living in Manaus, Northern Brazil. METHODS:Descriptive study with ecologic time series design carried out in Manaus from 2002 to 2009. Hospital admission data were obtained from the Unifi ed Health System database. PM 2.5 levels were estimated using aerosol remote sensing through the measurement of aerosol optical depth at a wavelength of 550 nm. Statistical methods were used in the data analysis, with Pearson correlation and multiple linear regression between variables, with a 95% confi dence interval. RESULTS:The region of Manaus showed low PM 2.5 concentrations when compared to the Southern Amazonian region. Between August and November (dry period in the region), was when the highest mean levels of PM 2.5 , estimated between 18 to 23 μg/m³, and the largest number of fi res were observed. For the rainy season, an average of 12 μg/m³, 66% lower than the dry season measurements (20.6 μg/m³) was observed. The highest rates of hospitalization were observed during the rainy season and April was the month with the highest levels at 2.51/1,000 children. A positive association between hospital admissions and relative humidity (R = 0.126; p-value = 0.005) was observed, while the association between admissions and PM 2.5 was negative and statistically signifi cant (R = -0.168; p-value = 0.003). The R² of the fi nal model (Hospitalizations = 2.19*Humidity -1.60*PM 2.5 -0.23*Precipitation) explained 84% of hospitalizations due to respiratory disease in children living in Manaus, considering the independent variables statistically signifi cant (humidity, PM 2.5 , and precipitation). CONCLUSIONS:Hospital admissions for respiratory diseases in children in Manaus, were more related to weather conditions and in particular relative humidity, than to exposure to aerosols emitted by biomass burning in the Amazonian region.

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Desmatamento na Amazônia: dinâmica, impactos e controle

Cited by 187 publications

References 24 publications

Possible impacts of climate change on wetlands and its biota in the Brazilian Amazon

Possible impacts of climate change on wetlands and its biota in the Brazilian Amazon

Atributos químicos, físico-hídricos e mineralogia da fração argila em solos do Baixo Amazonas: Serra de Parintins

Aerossois de queimadas e doencas respiratorias em criancas, Manaus, Brasil

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