Navegando por Assunto "Floresta"

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Acesso aberto (Open Access)
Análise da contribuição da pecuária bovina nas mudanças de uso da terra: uma abordagem multiescala no estado do Pará.
(Universidade Federal do Pará, 2021-02-19) THALÊS, Marcelo Cordeiro; RUIVO, Maria de Lourdes Pinheiro; http://lattes.cnpq.br/9419564604488031; https://orcid.org/0000-0002-6222-5534
Brazilian Amazon has gone through a number of different economic cycles linked to the exploitation of natural resources, integrated with global markets, which have intensified since the 1960s, most recently through the ongoing expansion of agribusiness. During this process of territorial construction, land use changes have occurred heterogeneously in both space and time, with mechanisms operating at a number of different scales. The present study analyzes the shifts in land use and the contribution of cattle ranching to the process of territorial construction based on monitoring methods and indicators applied at varying scales, from the local to the regional, as a contribution to territorial management. In the Brazilian state of Pará, the study was based on the diachronic cartography of the pioneer fronts, which was used to represent and delimit the regional contrasts among these fronts. The relationship between these pioneer fronts and the dynamics of the deforestation process was also analyzed, by period, between 2002 and 2017, which allowed the territories to be classified as (i) consolidated, in which ranching is being intensified, (ii) expanding, in which the fronts are used as a strategy of occupation, and (iii) areas free of deforestation. In the municipality of Paragominas, located in a territory undergoing consolidation, the landscape dynamics were analyzed by superimposing the maps of land use with those of the agricultural aptitude of the land and the distance to the principal highways, with the aim of developing a model for the restoration of the landscape. The local landscape dynamics can be divided into two principal systems of land use, one that is based on the expansion of the pasture in valleys with sandy soils, and the other, based on mechanized farming, which is currently expanding on the clayey plateaus. The analysis of these two systems provided three important insights for the eventual restoration of the landscape. The first point is that the intensification of land use increases the pressure on the forests, principally in the areas most adequate for farming. The second is that the intensification of land use frees up areas that are inadequate for mechanization, and could potentially be used for the restoration of the forest. The third point is that local governance should be employed to define spatially explicit policies capable of transforming the landscape. In the areas sampled, in southeastern Pará, observations were conducted at specific points for visual description of the characteristics of the pasture, which were used to construct a typology of the process of pasture degradation. When this pasture typology is related to the vegetation indices (NDVI, EVI-2, NDII-5, NDII-7) extracted from Landsat 7 (ETM+) images, it can be noted that the well-formed pasture, which is associated with a reduction in the cover and height of the vegetation, was also related to a reduction in the vegetation indices. In degraded and degrading pasture, there was a lack of precision in the differentiation of the well-formed pasture. The degraded pastures or those undergoing biological degradation were identified better, but still imprecisely in comparison with the well-formed pasture with low vegetation cover, whereas the pasture undergoing agricultural degradation was confused with the well-formed pasture with a medium to high percentage of vegetation cover. This approach has considerable potential for the monitoring of areas of pasture, but needs to be refined. The analyses at different scales reflect the importance of understanding shifts in land use during the process of territorial construction, with the primary objective of transforming this knowledge into an easily-understood diagnostic tool that should facilitate adequate decision-making.
Acesso aberto (Open Access)
Cura ou conservação: um dilema socioambiental na formação continuada de professores da educação
(Universidade Federal do Pará, 2017-04-10) BARBOSA, Lidiane Amaral; RAPOSO, Elinete Oliveira; http://lattes.cnpq.br/6737474841439654; https://orcid.org/ 0000-0001-8995-0296; FREITAS, Nádia Magalhães da Silva; http://lattes.cnpq.br/2982253212145468; https://orcid.org/0000-0003-0042-8640
Climate change, desertification, deforestation, burning, extinction of species of fauna and flora, are some of the issues that mark the environmental crisis and, from this scenario, some questions arise, such as the rationality of the thinking of the present civilization, man as centrality of the universe, the values of domination of nature, the uncontrollable and unsustainable process of production, the reinforcement of the culture of consumption, the constitution of an economized world. It is in this context that the contemporary socioenvironmental challenges are presented: socio-environmental quality and sustainability of cities, mitigation and confront with climate change, water and solid waste management, forest management, growing demand and energy alternatives, among others. The meaning here attributed to the term challenge refers to the possibilities of overcoming the aggravations that matter in unsustainability. This dissertation deals with what today represents one of the contemporary socio-environmental challenges - the forest. Thus, the research was driven by the following question: how teachers, in a process of continuous formation, base their decision-making in the face of a socioenvironmental dilemma involving the forest theme? The research presented a qualitative approach, and occurred in the context of a process of continuous training of teachers of basic education, which aimed to problematize the recent socio-environmental challenges. The analyzes presented referred to the secondary data produced in one of the formative activities, precisely of a case study (fictitious but verisimilious) entitled "Cure or conservation: the questions of human health and the ecosystem", that involved a socio-environmental dilemma, which involved the extraction of an antitumoral bioactive (paclitaxel - commercial name taxol), found in the Taxus brevifolia (pacific yew - vulgar name), present curiously in indigenous lands, in the Amazon. The positioning of the professors, in general lines, manifested the integration of knowledge of two areas: natural sciences and social sciences, approaching them. The teachers called attention to the need to abolish the existing gap between these two areas, constituting a paradigmbreaking movement and dialogues between disciplines. The teachers considered aspects such as identity, culture and traditional knowledge, avoiding positions that exorcize the otherness and the sovereignty of scientific knowledge in relation to others. Socioenvironmental issues are difficult to approach given their complex nature. Thus, thinking about the forest, especially the Amazon rainforest requires a differentiated approach, considering its multidiverse nature, as did the teachers in their positioning. They evoked aspects beyond their specific training, integrating knowledge, in an authentic interdisciplinary attitude in the consideration of the socio-environmental dilemma proposed in the training. The teachers' discussions were legitimate and their positions relevant and current, when considering the aspects involved in the socio-environmental field.
Acesso aberto (Open Access)
Dinâmica da cobertura florestal a partir de análises realizadas em áreas de extração seletiva de madeira no Estado do Pará
(Universidade Federal do Pará, 2023-09-29) ROCHA, Nívia Cristina Vieira; GALBRAITH, David; http://lattes.cnpq.br/2145475131329843; ADAMI, Marcos; http://lattes.cnpq.br/7484071887086439; https://orcid.org/0000-0003-4247-4477
The selective logging in the Amazon region is an activity that holds relevance in social, economic, and environmental aspects. In many cases, this is considered a low environmental impact activity in the forests when compared to deforestation. This research assessed canopy opening in selectively logged areas in Eastern Amazon over different years with reduced impact. Detailed monitoring was conducted in these areas using both hemispherical images and orbital images to evaluate the persistence of impacts over time. Hemispherical photographs were used to measure canopy opening and provide a high-resolution assessment of the logged areas. This study also utilized images obtained from Landsat, Sentinel, and Planet satellites. Spectral Mixture Analysis and enhancement techniques were applied to these orbital images to detect canopy opening impacts caused by selective logging. Hemispherical images revealed that even 17 years after the logging activities ceased, the impacts caused by selective logging were still discernible. Meanwhile, orbital images allowed for the identification of logging at different time intervals depending on their respective resolutions. From the results, this study highlights the importance of the combined use of hemispherical and satellite images to monitor the effects of selective logging over time in the Amazon. This enables a more comprehensive understanding of forest dynamics, the persistence of impacts, and the importance of continuous monitoring in logged areas to assess long-term effects and adopt sustainable management strategies.
Acesso aberto (Open Access)
Dinâmica da paisagem na porção norte da Ilha do Bananal-TO e adjacências ao longo do Quaternário tardio.
(Universidade Federal do Pará, 2019-08-30) MENDES, Laís Aguiar da Silva; COSTA, Marcondes Lima da; http://lattes.cnpq.br/1639498384851302
Paleoclimatic and paleoenvironmental studies aim to understand processes of global landscapes evolution, contributing to the reconstitution of the quaternary landscapes and the climatic and environmental changes to which were submitted during this period of the earth's geological history. Some studies in the Amazon, but especially those led in regions more sensitive, such as ecotones and wetlands, show that these areas underwent various paleoecological changes during the Pleistocene and Holocene. The present study was led in the Bananal Island region located in a transition area between the Amazon and Cerrado biomes. The Bananal Island, considered by many authors the largest river island in the world, occupies an area of about 20,000 km2 and is located between the middle course of the Araguaia River and its tributary by the right branch, the Javaés River, in the state of Tocantins. The northern portion of the island stands out for its complex mosaic of geomorphological features (marginal dikes, abandoned meanders, paleochannels and lakes) and contrasting geobotanical features (forests and savannas), such that reflect the intense hydrodynamic activity in this region. Seasonally it is flooded by rainwater and rising water table, so it is considered a seasonal wetland. The aim of this work is to understand the dynamics of this landscape, based on the mineralogical and chemical composition of soils and sediments and the palynological composition study of lacustrine sediments of this region. Therefore, samples of ravines exposed on the banks of Javaés and Araguaia rivers, sandy bars and lake sediments were collected. Soils and sediments were analyzed for their mineralogy by X-ray diffraction and chemistry by ICP-AES and ICPMS. The sediment cores collected in 2 distinct lakes, one located in the interior of the northern portion of Bananal Island (Quatro Veados Lake) and the other located on the surroundings of the Javaés River (Mata Verde Lake) were analyzed for their palynological content and dated by AMS 14C. The results of this research are presented in 3 articles: the first one treaties about the mineralogy and geochemistry of the soils and sediments of Bananal Island, the bars and ravines along the Javaés River. Therefore, it discusses about the diversified nature of the minerals and chemical elements that the strata and horizons of these surface covers are composed, pointing to geological provenance, as well as the geochemical processes involved in the current and past dynamics of this landscape. The second article presents the dynamics of vegetation over the last 2000 years AP in the interior of Bananal Island and discusses its relationship with local climatic and edaphic conditions. The third article, on the other hand, describes the vegetational succession occurred in the last 400 years AP, based on the pollen record of sediments from a lake located on the Bananal Island surrounds, and analyzes the modern pollen spectrum in the region. The results obtained through this work present a highly diversified landscape in terms of its geoforms, sedimentary and pedogenetic coverings and geobotanical aspects resulting from the various moments of its geological history and which even today is dynamic and intriguing. The soils and sediments of this landscape are varied as their textures (sequences of sandy and clay materials) and mineralogical and chemical compositions, where primary minerals and derivatives of varied degrees of chemical weathering coexist in the same profile, showing moments of contrasting climatic conditions. Even, nowadays it is possible to observe in situ environments with variable dynamics (erosive, sedimentary, pedogenetic, etc.), as well as, several geochemical processes, such as those of oxidation of sandy bars and ravines and also the reductive processes of these ferruginized sands (sometimes, mistakenly confused for lateritic profiles), due to contact with organic acids produced by forest cover and hydromorphic conditions such as they are subjected. Regarding vegetation changes throughout the late Holocene, climate control was observed, but especially edaphic, since this area is seasonally flooded, a fact favored by the clayey nature of the soil surface horizons, the rainfall high rates as a prolonged rainy season (on average 6 months) and extensively flat terrain. Thus, factors such as flood duration and hydromorphism conditions stemming are responsible for controlling the installation of forests and/or savannas that characterize the region. So, the regency of a drier climate with the shortening rainy seasons that causes the water table rise, may represent favorable conditions for the development and advancement of the forest. On the other hand, a wetter climate with longer rainy seasons would cause flooding, covering larger areas and the soils would remain saturated for longer periods, a fact that undermines the advancement of the forest and allows the maintenance or even expansion of savannas, especially those dominated by grasses over the region. However, as already mentioned, the climatic conditions in this region control the expansion of forest formations, but they are not the only protagonists in this process, since the presence of wetland due to low and flat topography, clay soils, soil and sediment saturation is an effective impediment to the forest installation. Another factor responsible for replacing for gallery forest by savanna’s tree, for example, is the channel abandonment, a fact that is currently observed in the region, where it is possible to tread inside these old river beds, many of these places already enriched with species such as Curatella americana and Byrsonima sp among others. The Bananal Island, which is geologically inserted in the context of the Bananal Basin and is bathed by one of the largest hydrographic basins in the Brazilian territory (Araguaia-Tocantins), sets up as an extremely important landscape for understanding the wetlands dynamics and also from the savanna-forest ecotone areas during the Quaternary, since, it fits in both situations. The northern part of the island where this research was developed still needs studies. However, in general, this research has contributed to understand the functional dynamics of this landscape in face of the region climate and environmental changes, as well as to increase the knowledge about the transition landscapes between the Amazon forest and savannas, such as the paleoenvironmental knowledge is still restricted.
Acesso aberto (Open Access)
Impacto da concessão florestal na geração de emprego local: caso de Itapuã do Oeste, Rondônia
(Universidade Federal do Pará, 2018-03-21) RIBEIRO, Jime Rodrigues; AZEVEDO-RAMOS, Claudia; http://lattes.cnpq.br/1968630321407619
In the humid tropics, the system of forest concessions has become the main mechanism for access to public forest resources. In Brazil, the forest concession was inaugurated as a public policy in 2006 through Law No. 11,284 of March 2, also known as the Public Forest Management Act. It had as one of its assumptions the generation of jobs in remote forest areas of Amazon. In order to assess if this impact has been effective around the first areas of forest concession in the country, the municipality of Itapuã do Oeste (Rondônia) was used as a case study. The impact of public policy was verified through the Synthetic Control technique for the period from 2002 to 2015. The impact on the generation of forestry jobs was felt starting in 2014, four years after the beginning of the operation of the concessions and was related to conjunctural factors, such as emergence of new concessions areas in Rondônia, contractual changes through federal resolution and compliance with local workers' qualification requirements. The municipality of Itapuã do Oeste benefited from increased jobs by concentrating the processing of the wood and receiving the demand for labor caused by other municipalities with forest concessions, but without the same structure. From this point of view, the planning of forest concessions in the Amazon would need to obey a regional perspective and in line with national and state development plans that overflow the sphere of environmental entities that now manage the concessions.
Acesso aberto (Open Access)
Interações entre nuvens, chuvas e a biosfera na Amazônia
(Instituto Nacional de Pesquisas da Amazônia, 2005-06) DIAS, Maria Assunção Faus da Silva; COHEN, Júlia Clarinda Paiva; GANDU, Adilson Wagner
A review of results obtained within the Physical Climate component of LBA with respect to the interaction between the biosphere and cloud and rain formation in the Amazon Basin, in different seasons and different regions within the Basin is presented. The deforestation effect and the effect of biomass burning are discussed and the physical processes highlighted based on the data collected in several LBA intensive field campaigns. The complex interactions and the progress in the understanding their evolution based on the new datasets is presented.
Acesso aberto (Open Access)
Método de inversão para a obtenção dos parâmetros elétricos do solo para região amazônica baseado em medições e usando equações parabólicas
(Universidade Federal do Pará, 2015-08-20) OLIVEIRA, Romulo Augusto Nascimento de; MAGNO, Fátima Nazaré Baraúna; http://lattes.cnpq.br/8466611553866661; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
In recent years, due to the rapid development of the technology of radio access digital such as TV Digital and digital audio broadcasting, accompanied by a strong demand for these types of services, it has become of great importance the study the electric field behavior generated by radio stations who will use these technologies as well as knowledge of electrical parameters involved, which are essential in determining of the stations coverage area. This work presents a methodology of inversion through weighted least squares to obtain the equivalent electrical parameters of the vegetation and soil of a typical Amazon forest region using the model based on the formalism of parabolic equations to calculate the electric field strength received by a mobile receiver contained within in this region. To validate this methodology, measurement campaigns were conducted in Benfica, Marituba and Barcarena, State of Pará. Since in Benfica and Marituba was used a frequency of 900 MHz and Barcarena was used the frequency of 1.8 GHz. For the three cities, the measuring system consisted of a laboratory fixed and a mobile station that has been set up to measure and store the instantaneous values of the received signal. The measurements were compared with computer simulations, and so it was possible to estimate the optimal values for the electrical conductivity and relative permittivity of the vegetation that cut the road access to the cities and of the highway soil through the proposed inversion methodology. It was also made a quantitative analysis of these parameters with the values found in the literature which demonstrated the effectiveness of the proposed methodology. Finally, this work presents the results obtained with the inversion method for a rural region located in the center of Brazil, where it was found that the estimated values for soil electrical conductivity were very close to those shown in recent studies to the region.
Acesso aberto (Open Access)
Mulheres, saberes práticos, relações de gênero e a floresta
(Universidade Federal do Pará, 2014-06) SILVA, Rubens Elias da; BONFIM, Fernanda da Silva; SOUZA, Rogério Ribeiro de
This work investigates the role of women collectors of seeds in the construction of practical knowledge with demarche gender relations as a nodal point for the elaboration of this knowledge in inspite of sexual and social divisions of work. The locus of the research is the Maguari community, located inside of National Tapajós Forest, Belterra, Western of Pará. The collectors of seed play the role of learning, to master n and use the resources available in the forest. This role is effectivated in knowledge across generations. Therefore the close contact with the same wedge the identity of the social group and gives them the sense of being and existence. The community forest land area according to our observations are made through social relationships between foresters and collectors of seeds. This association to the work of collectors becomes effective and can provide the capital injection required for social production, and also ensures the permanence of populations living within the forest. From what has been observed in the fieldwork is the existing differences in gender relations that emerge in the possible work tasks within the forest hatching in efficient social cooperation strategies between genders, reflecting discussions about echofeminism.
Acesso aberto (Open Access)
Riqueza e dinâmica espaço-temporal de minhocas (Annelida, Oligochaeta) em um fragmento florestal.
(Universidade Federal do Pará, 2019-07-02) BECKMAN, Ruana Aretha Farias Santiago; LAVELLE, Patrick Marie; http://lattes.cnpq.br/5850683517396587; MARTINS, Marlúcia Bonifácio; http://lattes.cnpq.br/8882047165338427
The richness, distribution and abundance of Oligochaeta species were analyzed in relation to environmental parameters (internal forest precipitation, litter quantity, texture, pH and soil moisture) during 15 months in an area located in the peri-urban region of the municipality of Belém, state of Pará, Brazil, that belongs to Embrapa Eastern Amazon state company with a reserve area that corresponds to 2,706 hectares. In this study were found eight species: Pontoscolex corethrurus, Muller 1857, four species not been described yet and another 3 not determined due to the lack of characters required for identification. Species richness approached that found in other Amazon forest sites, however, most species occured in low abundance and with sparse distribution. It was also noted low functional diversity with all species belonging to the endogenous ecological category. In the study, the predominant species was Pontoscolex corethrurus, which represented 96.94% of the total density while the others summed up 3.06%. P. coretrhurus was dominant in all points in the site and in all periods. Because of this, it was the only species studied in relation to soil and climate attributes. In this study their abundance responded significantly to the internal precipitation while litter quantity, soil texture, pH and soil moisture did not show considerable effects. Demographics showed that this is an Oligochaeta species that can remain on the soil all year long. It also mantains continued population development with their cocoons producing in three months of year. Although the number of species detected did not show drastic reduction, the high dominance of P. corethrurus, the low functional diversity, the rarity and dispersion of native species spatio-temporal distributions offer clear indications for biodiversity loss in soil fauna in this forest remnant. Possibly this is accompanied by loss of soil ecosystem functions, because of isolation and surrounding urbanization.