Navegando por Assunto "Ecossistema"

Agora exibindo 1 - 12 de 12

Acesso aberto (Open Access)
Balanço de água em área de cultivo de soja no Leste da Amazônia
(Universidade Federal do Pará, 2007) BISPO, Carlos José Capela; RIBEIRO, Aristides; http://lattes.cnpq.br/8652338930029697; ROCHA, Edson José Paulino da; http://lattes.cnpq.br/2313369423727020
The expansion of the agricultural frontier, driven mainly by soy cultivation (Glycine max (L) Merrill), covers a large regional extent and is highly important to understanding the changing face of Amazonia. A field observation experiment was established to study water balance components of the soy agriculture ecosystem and analyze the impact of the water balance associated with forest conversion. The experiment also evaluated the crop’s need for water according to its development phase. For the water balance study, the BRS Candeia cultivar was used along with its respective phenological phases. The experiment measured soil water storage, precipitation, plant cover water interception, superficial drainage of soil water, evapotranspiration (Etc), and water content retained by the soy plant. Water infiltration in the soil was also measured. Interception and superficial drainage were 45,9% and 1% of the precipitation, respectively. The greatest evapotranspiration occurred during the flowering phase (R1-R2) with a gradual decline in values until crop harvest and a cycle average of 3,80mm.day-1, which was very similar to that found in forest. The period between the vegetative phase (V) and fruiting (R3-R4) was when the plant presents the greatest percentage of water, declining gradually during the grain-forming phase (R5). Overall, no water deficiency occured in the mean soil water balance. Precipitation was greater than the amount necessary to compensate for evapotranspiration and supply adequate water storage, creating a surplus of water in the soil.
Acesso aberto (Open Access)
Comunidades macrobentônicas da Reserva Biológica do Lago Piratuba (Amapá – Brasil)
(Universidade Federal do Pará, 2008) ALMEIDA, Mayk Ferreira de; ROSA FILHO, José Souto; http://lattes.cnpq.br/3223362071251898; ALBERNAZ, Ana Luisa Kerti Mangabeira; http://lattes.cnpq.br/1220240487835422
The structure of the macrobenthic communities was characterized in different climatic periods and areas of the Reserva Biológica do Lago Piratuba (Amapá-Brazil). The samplings occurred on June and November of 2005 (Meridional belt lake - lakes Comprido de cima, Bacia, Lodão, Grande, Comprido de Baixo, Canal Tobaco and estuary of the river Araguari) and of 2006 (eastern belt lake - lakes Piratuba, Jussara, Escara, Trindade, Maresia, Boiado and the Duarte stream and seven places in the coast (areas vegetated and not vegetated). At each site four samples had been collected, with a corer (0.0079 m2) buried 20 cm in the sediment. After collection samples were passed in a 0.3 mm mesh and the retained organisms were fixed in formalin 5%. The structure of the communities varied seasonally, with severe modifications in density, specific composition, richness, eveness and diversity among sampling occasions and environments (lakes/coast). A total of 54 taxa had been identified belonging to phyla: Annelida, Arthropoda, Mollusca and Nemertea. In the rainy seasonal it was recorded 36 taxa, and in the dry seasonal 42 taxa were recorded. Annelida was the most abundant taxon, representing always more than 48% of total organisms. In the lakes Insecta larvae, Mollusca and Oligochaeta were the dominant taxa. In the coast, Polychaeta and Crustacea were dominant. It was recorded 32 taxa in the lakes and mean density of 667 ind.m-2. In the coast 34 taxa were recorded and 1353 ind.m-2. The coastal non-vegetated area was richer and denser and showed the higher eveness. Benthic fauna from the Meridional belt lake and the Eastern belt lake behavioured distinctively among seasons. Three sub-environments had been identified based on the benthic fauna: freshwater environment - majority of the lakes of the Eastern belt, dominated by insects; transition environment (freshwater/coast) with mixed fauna (Polychaeta and Insecta); and coastal environment, with Polychaeta and Crustacea. The environmental characteristics best correlated with spatialtemporal changes in the benthic communities structure were water pH, electric conductivity and turbidity.
Acesso aberto (Open Access)
Consistência e uso das informações sobre ameaça no processo participativo de indicação de áreas prioritárias para a conservação da Amazônia
(Universidade Federal do Pará, 2014-02-27) CASTRO, Rodrigo Baia; ALBERNAZ, Ana Luisa Kerti Mangabeira; http://lattes.cnpq.br/1220240487835422
Despite academic progress, planning for conservation has failed in performing actions that prioritize biodiversity conservation. New strategies have been proposed to increase the effectiveness of conservation plans, including the realization of decision-making processes with broad participation, facilitate social acceptance of the shares. This article analyzes how information about the threats were used in the decision-making for indicating priority areas for the conservation of the Amazon, in the coordination of the Brazilian Government in 2006 process. First we verified the consistency of information on threats attributed to new areas indicated, and then assess whether the existence, levels and types of threats defined by the participants influenced the indication areas for conservation. The results show that there have been some successes in recognition of threats, but also some inconsistencies, especially in assigned levels and types of low intensity threats such as fishing. The decision making process is also not fully used this information for the indication of areas for conservation. The lack of information about the motivations of these inconsistencies leave no doubt as to the presence of political opportunism, but point out that the participatory process should be allocated a larger effort to combine the participatory decision support systems process in order to generate a priority order more quantitative and less dependent on the individual selection of the participants, to reflect more directly to actual emergency deployment.
Acesso aberto (Open Access)
Desenvolvimento sustentável e uso dos recursos naturais em áreas de várzea do território do baixo Tocantins da Amazônia paraense: limites, desafios e possibilidades
(Universidade Federal do Pará, 2016-06-19) REIS, Adebaro Alves dos; ALMEIDA, Oriana Trindade de; http://lattes.cnpq.br/0325909843645279
The central goal of this thesis is to understand and analyze the dynamics of sustainable use the natural resource by the cabocla-riverside populations aiming the application of sustainable development concept and, starting the observation the everyday the way of life, the use of natural resources and the process of diversified production as empirical elements required to think a new pattern of development, in other words, the sustainable, anchored to traditional knowledges of cabocla-riverside populations of lowland areas the territory of Baixo Tocantins of Amazon Paraense. Like this, sought , starting of theoric debate, develop a criticizes to modern science, with specificity to instrumental rationality, that promoted fragmentation the relationship between man and nature, through development of destructive activities the natural resources that compromise the own human life , the same time, was introduced an approach of interdisciplinarity as one possibility of articulation in different areas of knowledge for a intervention under perspectives of dimensions the social life and natural. The study to elaborate this thesis has as universe the Baixo Tocantins territory, where it considered the lowland ecosystems of municipalities Abaetetuba and Igarapé-Miri, in their components considered strategic like: riverside communities, agro ecosystem and riverside population, constitutive the Tocantins river margin. For this, was reconstituted of synthetic mode, the historical trajectory of this territory through of occupation, development, and use of natural resources, which were analyzed from adaptive productive dynamics , and use of natural resources in their multiple activities of management of lowland ecosystem focused for production and management of açaí , agroforestry systems (SAFs), agriculture, creating of small and medium-sized animals , creation of fishes, vegetal extractivism and animal , shrimp fishery and fish on lowland ecosystem. This practices of use the natural resources, traditionally employed by inhabitants of lowland areas makes part of one lifestyle, that secularly has guaranteed the production of knowledge acquired/inherited of past generations, how management and use nature resources of this agrosystem. The productive diversity strategies, management and multiple uses the nature resources follows the rhythms imposed by nature of adaptation capacity of relation with natural conditions of lowland areas, such as : flood process, flood and ebb the rivers, erosion/ deposition , environmental impacts by great developmental projects, elevated levels of the rivers , among others factors, keeping a high degree of interrelationship balanced with nature. Can mean that, in the lowland ecosystem, man and nature are completed, creating a single standard of sustainable development.
Acesso aberto (Open Access)
Dinâmica do carbono em pequenas bacias de drenagem sob uso de agricultura familiar na Amazônia Oriental
(Universidade Federal do Pará, 2007) ROSA, Maria Beatriz Silva da; FIGUEIREDO, Ricardo de Oliveira; http://lattes.cnpq.br/2388049759708934
This research was designed to evaluate carbon dynamics in Eastern Amazon, where the main land use is small holder farming, and was conducted in three small catchments. Carbon dynamics was evaluated considering hydrological and biogeochemical measurements in Cumaru, Pachibá and São João streams from June 2006 to May 2007. Aquatic environment and fluvial hydrogeochemistry were characterized through in situ measures of electrical conductivity, temperature, pH and dissolved oxygen concentration. Water samples were collected and analyzed to determine dissolved organic carbon (DOC) concentrations and carbon dioxide partial pressures (pCO2). Concentrations of dissolved inorganic carbon (DIC) were calculated from pCO2 values. Despite being calculated from pCO2 values, CO2 fluxes were also measured in situ. Instantaneous discharge was measured in each month field campaign and used to calculate DOC annual fluxes. Soil and land use characterization in the study watersheds, as well as precipitation and discharge rates, were considered for results interpretation. Main results were: 1) Stream water physic-chemical characteristics in the study catchments respond to the acid soils, riparian vegetation, and the hydrological and biogeochemical processes in the terrestrial and aquatic ecosystems, and present some seasonal variation. 2) Dissolved carbon concentrations was correlated with pH and dissolved oxygen in stream water; 3) DOC fluxes weighted by area were higher than in other Amazonian watersheds and even higher during rainy season; 4) DOC fluxes and CO2 evasion seem to respond positively to riparian vegetation and mature forest, and negatively to agriculture; 5) CO2 evasion rates were higher than in other Amazonian rivers corroborating the hypothesis that small catchments are important sources of atmospheric CO2 in the region.
Acesso aberto (Open Access)
Efeito do tamanho da área florestada, grau de isolamento e distância de estradas na estruturação de comunidades de aranhas em Alter do Chão, Santarém, Pará
(Universidade Federal do Pará, 2008-10-24) SILVA, Bruno José Ferreira da; BONALDO, Alexandre Bragio; http://lattes.cnpq.br/8721994758453503; ALBERNAZ, Ana Luisa Kerti Mangabeira; http://lattes.cnpq.br/1220240487835422
As forest destruction and fragmentation advance throughout the Brazilian Amazon, it has become important to determine how these processes affect the fauna in various vegetation types in order to predict impacts and the conservation value of habitat fragments for different animal taxa. Invertebrates are useful bio-indicators because of their adaptive and dispersal potential and intimate connections with the environment. The use of spiders to evaluate forest fragmentation is recent and only slightly employed, although the group is mega-diverse and biologically tied to environmental composition and structure. This study used spiders to evaluate the effects of forest fragment size, degree of isolation, and distance to roads in 15 forest islands in a savanna matrix and 6 areas of continuous forest, in Alter do Chão district, Santarém municipality, Pará state, Brazil. Capture of spiders involved 252 man-hours of effort with an entomological umbrella and manual nocturnal collections. Transects of 250 m were collected three times, and the summed results of each transect comprised a sample unit. In total, 7751 spiders were captured, including 5477 immature and 2274 adult specimens in 306 species belonging to 32 families. Spider community characteristics, analyzed by MDS (Multidimensional Scaling) with Bray-Curtis distance, showed separation between continuous forest and forest fragment habitats. For species with more than 10 individuals in the collections, an analysis was made of the response to the first dimension of ordination, and a direct ordination was made using characteristics of each collection area (distance from the forest island to continuous forest, area of forest fragment, and form index of the forest island). GLM analysis, used to evaluate the effects of environmental degradation, showed significant differences for number of trees in each forest fragment and for distance to roads: forest fragmentation was significant to spider communities only in terms of size of forest fragment (on axis 1 of the MDS). An ANOVA used to compare species richness showed greater richness in continuous forest, differing from the result of rarefaction curves that predict slightly higher species richness in forest islands. The hierarchical standard of the spider community was obtained with the Nestedness Temperature Calculator Program–Nestcalc.
Acesso aberto (Open Access)
Fauna associada as bromelias Cannistran aff. giganteum (Baker) L. B. Smith e Neoregelia cruenta (R. Graham) L. B. Smith de restinga do litoral norte do Estado de São Paulo
(Universidade Estadual de Campinas, 1981) FERREIRA, Clara Pantoja; BENSON, Woodruff Whitman; http://lattes.cnpq.br/7116492347323901
An experimental set up for the study of tablets coating in a two-dimensional spouted bed that uses vibration of the perforated base to enhance the circulation of the particles was developed. An acrylic rectangular upper section (4x32 cm) with fixed 4x4 cm draft plates was adjusted over 3 different convergent secctions (inclination 50') with 4x4 cm, 4x6 cm or 4x8 cm bases and contained 800g, 1100g or 1300g of tablets, Air (0,8 to 1,6 m3/min) forced by a 7,5 cv blower, was cooled down to 55°C and spouted this bed. The lenticular tablets (0,12g; 0,25g., 0,44g) were coated with a polymeric aqucous solution (11% solids). A two-fiuid atomizer (air pressure 82,7 1(.Pa) was used, inserted lateraily, near the bed base, and showed no influence on the movement of the particles. The experimental characterization of the tablets circulation rates was emphasized, using a magnet (0,4062 g) that followed the particles, activating a bobbin located at the upper end of the draf plates, The electric pulses were processed by a data acquisition sistem and the cicie time distribution curves were adjusted by the Modiíied Spline fit technique. The mean of the cicie t.in e distribution creased with are increase of the bed load and the size of the ta.blets in ali comparative tests. The vibration (10 Hz, 8 mm amplitude) reduced the mean of the cicie time distribution by more than 10%, and also decreased its variance. The vibration ais() aí ected the maxirnum pressure drop (40% reduction) and the minimum spouting velocity The vibro spouted bed showedhigher- adhesion efficency (73 to 88%) than the non-vibrated spouted bed (66 to 79%) in ali equivalent situations and the complete coating of the smailer tablets dema.nded iess processing time due to higher surface arca circulation rate.
Acesso aberto (Open Access)
Incidência de malária no Estado do Pará e suas relações com a variabilidade climática regional
(Universidade Federal do Pará, 2007-11-23) PARENTE, Andressa Tavares; SOUZA, Everaldo Barreiros de; http://lattes.cnpq.br/6257794694839685
The objective of the present work is to approach a diagnostic study on the malaria incidence in four different regions over the Pará state in the eastern Amazon, seeking its relationships with the regional climate variability, with the population growth and rates of deforestation. Time series containing 35 years of annual data (1970-2005) and 14 years of monthly data are used. The percentiles technique was employed in order to establish five categories or classes of the malaria incidence rates and precipitation for each municipal district.Results based on the analyses using annual data showed that the cities present different factors that contribute to the endemic profile. The growth of the population has direct relationship with the increased malaria incidence in Anajás, Itaituba and Santana do Araguaia. In Anajás, the precipitation was not a decisive factor in the occurrence of the parasitosis. In Santana do Araguaia and Viseu the highest rates of the malaria incidence occurred in years with rainfall deficit. For Viseu, the normal precipitation pattern also categorized high malaria incidence. Concerning the deforestation rates from 1988 until 1995, the curves of malaria incidence follow the deforestation rates. From 1995 onwards, it was evidenced consecutive years of high rates of malaria incidence just after the years characterized with higher deforestation rates, as observed during 1995, 2000 and 2004. Composites analyses based on objective selection of the indices of malaria occurrence categorized by the percentiles, allowed to define annual features of the regional climate variability in each city. In general, years with higher malaria indices area associated with the Pacific El Niño and warmer than normal oceanic conditions over the north Atlantic basin, while the years with lower malaria indices are related to the Pacific La Niña and no significant signal in the tropical Atlantic Ocean. Results obtained from monthly data base, using composites based on objective selection of climate events observed over Pacific and Atlantic Oceans, it was investigated the response of such mechanisms on the monthly evolution of the malaria incidence over the Pará state. The El Niño composites revealed "negative" impacts, i.e., systematic and significant increase in cases of malaria occurring in a sequence of months in Itaituba and Santana do Araguaia. For Anajás and Viseu, the El Niño scenario is associated with "positive" impacts i.e., malaria incidence in the medium and low categories. Concerning La Niña composites, a widespread response over most of Pará state is verified, with predominance of higher malaria incidence in the four cities and processing persistently during the consecutive months from December to May. The composites for the positive dipole events in the intertropical Atlantic showed intra-regionally differentiated 11 malaria indices over the state, with Anajás and Itaituba presenting predominance of increased cases, while in Santana do Araguaia and Viseu presented several months with normal rates and below than average. Except for Itaituba, composites for the negative dipole events in the intertropical Atlantic evidenced malaria incidence in the medium and low categories, evolving from November to May.
Acesso aberto (Open Access)
Novel Microsatellite Markers for Brazilian Mangrove Oysters ( Crassostrea gasar ) and their Cross-Amplification in Crassostrea rhizophorae
(Universidade Federal do Pará, 2016-08) BALDEZ, Renata do Socorro Corrêa; MELO, Mauro Andre Damasceno de; SAMPAIO, Maria Iracilda da Cunha; TAGLIARO, Claudia Helena
A microsatellite CT/GT enriched genomic library was developed for Crassostrea gasar and twelve new polymorphic loci were isolated and characterized. The markers were successfully amplified from 25 individuals of Crassostrea gasar and 11 cross-amplified individuals of Crassostrea rhizophorae. There was no evidence of linkage between loci in either species.
Acesso aberto (Open Access)
Radiation balance in a soybean ecosystem in the Amazon
(2010-12) SOUZA, Paulo Jorge de Oliveira Ponte de; ROCHA, Edson José Paulino da; RIBEIRO, Aristides; SOUZA, Everaldo Barreiros de
The continuous advance of the agricultural border in the Amazon has been worrying the scientific community due to the possible environmental impacts caused by this change in land use. The present work evaluated the behavior of the radiation balance components over the soybean crop (Glycine Max (L.) Merryl) in an Amazon area of continuous advance of the agricultural border. The radiation components were continuously monitored during the soybean cycle in 2006 and 2007 in an area of 200 ha. The soybean cultivation in the Amazon presented an abrupt change in the radiation balance components, with the consequent reduction in the energy available to the environment due to the increase in the surface reflection. There was a significant contribution of the diffuse radiation component in the soybean interception during cloudy conditions, even under incomplete canopy covering. Moreover, after the canopy closure, a similar interaction between soybean and solar radiation occurs, regardless of the cloud condition.
Acesso aberto (Open Access)
Selectivity curves of the capture of mangrove crab (Ucides cordatus) on the northern coast of Brazil using bayesian inference
(Instituto Internacional de Ecologia, 2016-06) FURTADO JUNIOR, Ivan; ABRUNHOSA, Fernando Araujo; HOLANDA, Francisco Carlos Alberto Fonteles; TAVARES, Marcia Cristina da Silva
Fishing selectivity of the mangrove crab Ucides cordatus in the north coast of Brazil can be defined as the fisherman's ability to capture and select individuals from a certain size or sex (or a combination of these factors) which suggests an empirical selectivity. Considering this hypothesis, we calculated the selectivity curves for males and females crabs using the logit function of the logistic model in the formulation. The Bayesian inference consisted of obtaining the posterior distribution by applying the Markov chain Monte Carlo (MCMC) method to software R using the OpenBUGS, BRugs, and R2WinBUGS libraries. The estimated results of width average carapace selection for males and females compared with previous studies reporting the average width of the carapace of sexual maturity allow us to confirm the hypothesis that most mature individuals do not suffer from fishing pressure; thus, ensuring their sustainability.
Acesso aberto (Open Access)
Solar radiation use efficiency by soybean under field conditions in the Amazon region
(2009-10) SOUZA, Paulo Jorge de Oliveira Ponte de; RIBEIRO, Aristides; ROCHA, Edson José Paulino da; FARIAS, José Renato Bouças; LOUREIRO, Renata Silva de; BISPO, Carlos José Capela; SAMPAIO, Leila Sobral
The objective of this work was to evaluate the efficiency of soybean (Glycine max) in intercepting and using solar radiation under natural field conditions, in the Amazon region, Brazil. The meteorological data and the values of soybean growth and leaf area were obtained from an agrometeorological experiment carried out in Paragominas, Pará state, during 2007 and 2008. The radiation use efficiency (RUE) was obtained from the ratio between the above-ground biomass production and the intercepted photosynthetically active radiation (PAR) accumulated to 99 and 95 days after sowing, in 2007 and 2008, respectively. Climatic conditions during the experiment were very distinct, with reduction in rainfall in 2007, which began during the soybean mid-cycle, due to the El Niño phenomenon. An important reduction in the leaf area index and biomass production was observed during 2007. Under natural field conditions in the Amazon region, the values of RUE were 1.46 and 1.99 g MJ-1 PAR in the 2007 and 2008 experiments, respectively. The probable reason for the differences found between these years might be associated to the water restriction in 2007 coupled with the higher air temperature and vapor pressure deficit, and also to the increase in the fraction of diffuse radiation that reached the land surface in 2008.