The objective of this paper is to present a method for mapping burnt areas in Brazilian Amazonia using Terra MODIS data. The proposed approach is based on image segmentation of the shade fraction images derived from MODIS, using a non-supervised classification algorithm followed by an image editing procedure for minimizing misclassifications. Acre State, the focus of this study, is located in the western region of Brazilian Amazonia and undergoing tropical deforestation. The extended dry season in 2005 affected this region creating conditions for extensive forest fires in addition to fires associated with deforestation and land management. The high temporal resolution of MODIS provides information for studying the resulting burnt areas. Landsat 5 TM images and field observations were also used as ground data for supporting and validating the MODIS results. Multitemporal analysis with MODIS showed that about 6500 km 2 of land surface were burnt in Acre State. Of this, 3700 km 2 corresponded to the previously deforested areas and 2800 km 2 corresponded to areas of standing forests. This type of information and its timely availability are critical for regional and global environmental studies. The results showed that daily MODIS sensor data are useful sources of information for mapping burnt areas, and the proposed method can be used in an operational project in Brazilian Amazonia.
The Ecuadorian Amazon is considered a biodiverse region, and at the same time contains the largest number of oil blocks and oilfields in the country. Oil exploitation requires the implementation of oil facilities and related infrastructure, such as roads, water, and energy supply, for operation. These large engineering works can alter the dynamics of the Amazonian natural ecosystems. This paper analyzes the land use and land cover (LULC) change and relates spatial patterns within an oil block located in the province of Orellana, Ecuador. The study was processed in two phases, the first corresponding to the collection and classification of LULC classes within the oil block. The second phase concerned the calculation of landscape metrics, with the purpose of quantitatively characterizing each class. This analysis was carried out for the pre-concession, post-concession scenarios of the oil block and the current scenario of the region. The results revealed that the low predominance of forest cover within the study region is not directly associated with the beginning of the Block 47 concession. On the other hand, a significant reduction of the Coca River was evidenced for the 2018 scenario.
The expansion of hydroelectric dams that is planned, and under construction, in the Amazon basin is a proposal to generate “clean” energy, with the purposes of meeting the regional energy demand, and the insertion of Brazil into the international economic market. However, this type of megaproject can change the dynamics of natural ecosystems. In the present article, the spatiotemporal patterns of deforestation according to distance from the reservoir in the vicinity of the lake of Tucuruí, and within a radius of 30 km from it, are analyzed. A linear spectral mixture model of segmented Landsat-thematic mapper (TM), enhanced thematic mapper plus (ETM+), and operational land imager (OLI) images, and proximity analysis were used for the mapping of the land-cover classes in the vicinity of the artificial lake of Tucuruí. Likewise, landscape metrics were determined with the purpose of quantifying the reduction of primary forest, as a mechanism of loss of ecosystem services in the region. These methods were also used for the evaluation of the influence of the distance from the reservoir on the expansion of anthropogenic activities. This methodology was used for the scenarios of pre-inauguration, completion of phase I, beginning of construction phase II, full completion of the Tucuruí hydroelectric project, and the current scenario of the region. The results showed that the highest deforestation rate occurred in the first period of the analysis, due to the areas submerged by the reservoir and due to the anthropogenic disturbances, such as timber extraction, road construction, and the conversion of forests into large areas of agribusiness.
This paper analyzes the spatial pattern of changes in land cover in the municipality of Breu Branco, one of the seven municipalities directly affected by the Tucuruí reservoir, in the Brazilian Amazon. The analysis was performed using images Landsat satellite. It was carried out the mapping of the land cover classes and the quantitative characterization of the classes present in the municipality, during the periods of pre-inauguration, completion of phase I, beginning of phase II of construction and completion of the works of the Tucuruí hydroelectric power plant. The study was carried out in two phases, the first one corresponds to the application of the linear mixing model in segmented Landsat-TM images, executed for the mapping of the land cover classes. The second phase refers to the calculation of the landscape metrics, in order to characterize the classes quantitatively. The results revealed changes in the spatial pattern of forest cover in the municipality of Breu Branco, during the 26 years of analysis. The scenarios of 1999 and 2010 were the ones that presented the greatest expansion of deforested areas, referring to the scenarios of the phase II of construction of the Tucuruí hydroelectric power plant. The high level of fragmentation is associated with local highways and roads in the region, allowing connectivity between urban spots, facilitating access to new areas and converting forests into large areas for agribusiness.
Este artigo trata das tensões entre nacionais e estrangeiros em Belém do Pará nas primeiras décadas da República. A presença significativa de imigrantes, em grande parte portugueses na cidade de Belém, proporcionou o acirramento de tensões étnicas, onde nacionalismo transfigurou-se em antilusitanismo. O projeto republicado de modernização e consolidação de uma identidade nacional, por meio da missão do cruzador José Bonifácio de nacionalização da pesca no litoral brasileiro adensou as tensões entre trabalhadores, levando em 1920 a um ataque a várias casas comerciais de estrangeiros em Belém, incluído o apedrejamento do consulado português. Os periódicos paraenses designaram os envolvidos como “jacobinos” pelo seu caráter violento. Neste sentido analisamos a difusão dessas ideias nacionalistas entre os anos de 1890 a 1920 no Pará e as implicações no mundo do trabalho amazônico.
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