23736 research outputs found
Sort by
Characterization of the radiative impact of aerosols on CO2 and energy fluxes in the Amazon deforestation arch using artificial neural networks
No full textIn vegetation canopies with complex architectures, diffuse solar radiation can enhance carbon assimilation through photosynthesis because isotropic light is able to reach deeper layers of the canopy. Although this effect has been studied in the past decade, the mechanisms and impacts of this enhancement over South America remain poorly understood. Over the Amazon deforestation arch large amounts of aerosols are released into the atmosphere due to biomass burning, which provides an ideal scenario for further investigation of this phenomenon in the presence of canopies with complex architecture. In this paper, the relation of aerosol optical depth and surface fluxes of mass and energy are evaluated over three study sites with artificial neural networks and radiative transfer modeling. Results indicate a significant effect of the aerosol on the flux of carbon dioxide between the vegetation and the atmosphere, as well as on energy exchange, including that surface fluxes are sensitive to second-order radiative impacts of aerosols on temperature, humidity, and friction velocity. CO2 exchanges increased in the presence of aerosol in up to 55 % in sites with complex canopy architecture. A decrease of approximately 12 % was observed for a site with shorter vegetation. Energy fluxes were negatively impacted by aerosols over all study sites.. © 2020 BMJ Publishing Group. All rights reserved
Freshwater fish diversity hotspots for conservation priorities in the Amazon Basin
No full textConserving freshwater habitats and their biodiversity in the Amazon Basin is a growing challenge in the face of rapid anthropogenic changes. We used the most comprehensive fish-occurrence database available (2355 valid species; 21,248 sampling points) and 3 ecological criteria (irreplaceability, representativeness, and vulnerability) to identify biodiversity hotspots based on 6 conservation templates (3 proactive, 1 reactive, 1 representative, and 1 balanced) to provide a set of alternative planning solutions for freshwater fish protection in the Amazon Basin. We identified empirically for each template the 17% of sub-basins that should be conserved and performed a prioritization analysis by identifying current and future (2050) threats (i.e., degree of deforestation and habitat fragmentation by dams). Two of our 3 proactive templates had around 65% of their surface covered by protected areas; high levels of irreplaceability (60% of endemics) and representativeness (71% of the Amazonian fish fauna); and low current and future vulnerability. These 2 templates, then, seemed more robust for conservation prioritization. The future of the selected sub-basins in these 2 proactive templates is not immediately threatened by human activities, and these sub-basins host the largest part of Amazonian biodiversity. They could easily be conserved if no additional threats occur between now and 2050. © 2020 Society for Conservation Biolog
A new species of spiny driftwood catfish Spinipterus (Siluriformes: Auchenipteridae) from the Amazon basin
Full text linkAn expedition to the middle Rio Purus basin uncovered a remarkable new species of the genus Spinipterus. The new species has a very distinct and conspicuous colour pattern resembling a jaguar and it is almost four times larger than Spinipterus acsi, a small specimen (32 mm LS) from Caño Santa Rita, a right bank tributary of Río Nanay in Peru and a second specimen was reported from Rio Juruá, Amazonas State, Brazil. Although the new species is more similar in size and colour pattern to Liosomadoras, it shares the synapomorphies for Spinipterus. The new species differs from the congener by the following characters: (a) colour pattern with large black rosette-like spots over a light yellow to brown background (v. brown background with small dark blotches over the body); (b) adult body size reaching 104.5 mm LS (v. maximum known size 37.1 mm LS); (c) posterior process of cleithrum short, never reaching vertical through the dorsal-fin origin (v. posterior process long, surpassing vertical through the dorsal-fin origin); (d) seven soft pectoral-fin rays (v. six); (e) caudal fin truncated (v. caudal fin rounded). © 2019 The Fisheries Society of the British Isle
Dinâmica espacial dos incêndios florestais em Autazes, Amazonas
Full text linkWildfires cause great disturbance in the Amazonian forests. Their occurrence results from an
interaction between climatic conditions and land-use and land-cover change. In El Niño years,
the climate becomes drier and hotter in some parts of the Amazon region, such as central
Amazonia, and wildfires affect large areas of forest causing environmental, climatic and
socioeconomic impacts. Understanding of wildfire dynamics and their relationship with landcover change is important for mitigating wildfire effects. A useful tool in this process is
dynamic modeling of spatial data, which, through simulation of future scenarios, can provide
information for planning of prevention policies. The goals of this research were to map fire
scars and deforestation over a period of 31 years in the municipality (county) of Autazes (in
central Amazonia), to simulate the occurrence of these disturbances over the 2015-2025 period
based on the historical data, and to estimate the loss of biomass caused by these disturbances.
Mapping of fire scars was done visually using Landsat and Resourcesat images. Data on
deforestation were obtained from INPE/PRODES. The simulations were performed using
spatial-dynamics models in DINAMICA-EGO software. Biomass loss was estimated by
multiplying the simulated areas of deforestation by the biomass densities of the impacted forests
and, in the case of biomass losses from wildfire, the simulated area of fire scars was by
multiplied both biomass and a tree-mortality factor. Forest fires occurred only in 1997/98 and
2015/16, which were years of strong El Niño, besides 2009/10 that was less strong that the
others. The simulated area of wildfires was approximately 85% greater than the deforestation
area. Total simulated biomass loss was approximately 4.066 Gg from deforestation and
approximately 903 Gg from wildfire. We conclude that forest fires in Autazes are related to
strong El Niño events and that wildfire is responsible for degrading a larger area than
deforestation, although biomass loss is mainly from deforestation.Os incêndios promovem grandes distúrbios às florestas na Amazônia. A sua causa está
relacionada à interação entre o clima e as mudanças de uso e cobertura do solo. Em anos de El
Niño, onde o clima fica mais seco e quente em algumas regiões da Amazônia como a central,
os incêndios atingem áreas extensas de florestas causando impactos ambientais, climáticos e
socioeconômicos. Entender como a dinâmica dos incêndios ocorre e sua relação com as
mudanças de cobertura do solo contribui para a mitigação dos seus efeitos. Uma ferramenta
muito útil nesse processo é a modelagem de dados espaciais, que através da simulação de
cenários futuros pode fornecer informações para o planejamento de políticas de prevenção.
Com isso, os objetivos deste trabalho foram mapear o histórico dos incêndios e do
desmatamento no município de Autazes, simular a ocorrência destes distúrbios com base no
histórico para 10 anos a partir de 2015 em um cenário hipotético e estimar a perda de biomassa
nas áreas simuladas. O mapeamento das cicatrizes de incêndios foi realizado a partir da
interpretação visual, utilizando imagens dos satélites Landsat e Resourcesat. Os dados do
desmatamento foram obtidos do Programa de Monitoramento da Floresta Amazônica Brasileira
por Satélite (PRODES). As simulações foram realizadas utilizando modelos de dinâmica
espacial estruturados no software DINAMICA EGO. A estimativa da perda de biomassa
estimada através da multiplicação da área simulada do desmatamento e dos incêndios pela
densidade de biomassa florestal, no caso dos incêndios foi realizada ainda uma multiplicação
por um fator de mortalidade das árvores. Vimos que em 30 anos os incêndios ocorreram em
1997/98 e 2015/16 anos de fortes eventos de El Niños, além de 2009/10 onde o evento foi
menos intenso. A área simulada de incêndios foi aproximadamente 85% maior do que a
desmatada. A perda de biomassa foi de aproximadamente 4.066 Gg para o desmatamento e de
aproximadamente 903 Gg para os incêndios. Assim podemos concluir que eventos extremos de
EL Niño associados aos incêndios podem ter grande impacto nas perdas de biomassa. Os
incêndios observados em Autazes degradaram uma área florestal muito superior ao
desmatamento. No entanto, a maior parte da perda de biomassa foi originada pelo
desmatamento
New genus and species of Baetidae (Insecta: Ephemeroptera) from Brazil
No full textOne new taxon was brought to light during an Ephemeroptera survey in Roraima state, but it was not described. This new taxon was included in a cladistics analysis (as Gen A) in order to delimitate some Baetidae genera, and it was recovered as a new genus. Taking in account that the new genus and species status were already defined in a previously published paper, the objective of this study was to describe it based on imagoes and nymphs, and formally name it as Macuxi tunamore gen. nov. sp. nov. The new genus is sister group of Rhopyscelis Cruz, Salles & Hamada + Varipes Lugo-Ortiz & McCafferty clade, and can be differentiated from both mainly by the absence of long and stout setae on femora of all legs. Several characteristics were obtained in the morphological analyses to distinguish the new genus from other genera, but the paraglossa and glossa with pectinate setae, and claw with two rows of denticles, one reduced and other with apical ones larger than the others, are highlighted. © 2020 Magnolia Press
Design social e reuso dos pallets: estratégias para adequação/ projeção de mobiliário ambiental na Associação de Idosos do Coroado, Manaus (Amazonas)
No full textTropical Trees as Time Capsules of Anthropogenic Activity
Full text linkAfter the ice caps, tropical forests are globally the most threatened terrestrial environments. Modern trees are not just witnesses to growing contemporary threats but also legacies of past human activity. Here, we review the use of dendrochronology, radiocarbon analysis, stable isotope analysis, and DNA analysis to examine ancient tree management. These methods exploit the fact that living trees record information on environmental and anthropogenic selective forces during their own and past generations of growth, making trees living archaeological ‘sites’. The applicability of these methods across prehistoric, historic, and industrial periods means they have the potential to detect evolving anthropogenic threats and can be used to set conservation priorities in rapidly vanishing environments. © 2019 The Author
Padrão sazonal dos casos de malária e a relação com a variabilidade hidrológica no Estado do Amazonas, Brasil
Full text linkINTRODUCTION: Malaria is an infectious disease of high transmission in the Amazon region, but its dynamics and spatial distribution may vary depending on the interaction of environmental, socio-cultural, economic, political and health services factors. OBJECTIVE: To verify the existence of malaria case patterns in consonance with the fluviometric regimes in Amazon basin. METHOD: Methods of descriptive and inferential statistics were used in malaria and water level data for 35 municipalities in the Amazonas State, in the period from 2003 to 2014. RESULTS: The existence of a tendency to modulate the seasonality of malaria cases due to distinct periods of rivers flooding has been demonstrated. Differences were observed in the annual hydrological variability accompanied by different patterns of malaria cases, showing a trend of remodeling of the epidemiological profile as a function of the flood pulse. CONCLUSION: The study suggests the implementation of regional and local strategies considering the hydrological regimes of the Amazon basin, enabling municipal actions to attenuate the malaria in the Amazonas State.INTRODUçÃO: A malária é uma doença infecciosa de alta transmissão na região amazônica, porém sua dinâmica e distribuição espacial podem variar, dependendo da interação de fatores ambientais, socioculturais, econômicos e políticos e serviços de saúde. OBJETIVO: Verificar a existência de padrões de casos de malária em consonância com os regimes fluviométricos da bacia amazônica. MÉTODOS: Foram utilizados métodos de estatística descritiva e inferencial nos dados de casos de malária e nível d’água para 35 municípios do estado do Amazonas, no período de 2003 a 2014. RESULTADOS: A existência de uma tendência que module a sazonalidade dos casos de malária, devido a períodos distintos de inundação dos rios, foi demonstrada. Diferenças foram observadas na variabilidade hidrológica anual, acompanhada por diferentes padrões de casos de malária, mostrando uma tendência de remodelação do perfil epidemiológico em função do pulso de inundação. CONCLUSÃO: O estudo sugere a implementação de estratégias regionais e locais, considerando os regimes hidrológicos da Bacia Amazônica, possibilitando ações municipais de atenuação da malária no estado do Amazonas
Chvalaea yolkamini sp. Nov. (Diptera: Hybotidae), the first Mexican species of genus discovered on Instagram
No full textA new species of Chvalaea Papp & Földvári, 2002 is discovered after a photo on a social network and later collected in nature. Chvalaea yolkamini sp. nov. is described and illustrated here. In addition, for the first time we describe eggs with scanning electron microscopy and report on adult hunting behavior. Copyright © 2020 Magnolia Pres