969 resultados para Brazilian semiarid


Relevância:

60.00% 60.00%

Publicador:

Resumo:

Water scarcity is a reality for the inhabitants of the Brazilian semiarid region. The problem, in quantitative terms , is caused due to local climatic conditions due mostly to a water deficit. Qualitatively, results of multiple uses and resulting contamination by human activities. Eutrophication is presented as a threat to the sustainable use of water resources, in order to favor the predominance of dense populations of cyanobacteria, which can be potentially harmful to human health. The aim of this study is to understand the population dynamics of phytoplankton and cyanobacteria to assess water quality of reservoirs Santa Cruz do Apodi and Pau dos Ferros belonging to bacia Apodi Mossoró-RN . Water samples were collected monthly between October 2011 and May 2012 in reservoirs Santa Cruz do Apodi and Pau dos Ferros, in this latter , in Jan/12 we performed a diel profile . The abiotic variables obtained in the field and in the laboratory were: water temperature , dissolved oxygen , pH , turbidity , transparency , total nitrogen and total phosphorus . Phytoplankton samples were collected with a plankton net and bottle of Van dorn . Were performed : identification , quantification , calculation of biovolume , classification into functional groups and index calculation phytoplankton assembly ( Q ) , cyanotoxins were quantified by ELISA . Statistical analyzes supported the evaluation of the dynamics between biotic and abiotic factors. A questionnaire was conducted to examine the conceptions of the population, education professionals and students. The reservoir of Pau dos Ferros, shallow , turbid and eutrophic showed dominance of the functional group SN throughout the sample period . The phytoplankton biomass ranged from 20 to 70 mm ³ . L - 1, the lowest values coincided with the increase of the mixing zone and transparency, which contributed to the occurrence of a change in species composition phytoplankton . The application of the index Q proved relevant, the reservoir of Pau dos Ferros , depending on the species present , was classified ecologically as bad for almost the entire sample period . The reservoir Santa Cruz do Apodi showed low biomass ( 0.04 and 4.31 mm ³ . L - 1 ) and greater diversity in the phytoplankton composition . According to the index assembly (Q ), it showed moderate condition during most of the period influenced by different functional groups of typical meso- eutrophic environment (K S0, H1, C, F , J , E, D and N) . Associations of diatoms and green algae D and X1 succeeded populations of cyanobacteria in periods marked by greater instability in the system , caused by wind or rain. In summary , the occurrence of drought has a direct influence on the hydrological conditions of the reservoirs , in general, these events, reducing the reservoir level is directly related to decreased water quality and increased density of phytoplankton occurring predominance of cyanobacteria , the index Q reflected well to changes in phytoplankton composition , being a good indicator for biomonitoring of reservoirs in this study and survey of previous conceptions showed the need to work on environmental awareness for the preservation of water resources by conducting workshops for Environmental Education

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Environmental changes and their consequences on the global level have challenged the different fields of study to integrate towards effective solutions to minimize and /or equate the negative impacts of these changes in different types of environments. In this context, the Environmental Perception has been a widely used and relevant in studies that consider the relationship between the environment and human actions, by allowing analysis of perceptions, attitudes and values, key influencers of topophilia that resonates in conservation tool. Allied to Environmental Perception, Integrated Analysis of the Landscape is relevant because it allows to analyze in a systematic way the geographical space where all its elements are interrelated in a way that supports needed to understand the complex physical and human environment of a given environment. In this perspective, we have studied the João do Vale Serrano Complex, located in semiarid of Rio Grande do Norte state, which features a set of landscapes with different faces, which are being replaced by various economic activities and disordered population growth, with consequent exploitation the potential of natural resources. This thesis main goal was to combine the Environmental Perception of rural communities to the of Serrano Complex Landscape Analysis as additional criteria for the definition of Priority Areas for Conservation. The perception data were collected through direct observation, questioning, interviews and application forms to 240 people (100 % of occupied households in the mountain community) during the months of february and august 2011, with theoretical and methodological basis Environmental Perception. Integrated Landscape Analysis was performed by GTP (Geosystem - Territory - Landscape) method, using the Geographic Information System (GIS), using the technique of GIS for mapping the landscape. The results showed that respondents have a sense of topophilia by where they live, hold a vast knowledge of the natural resources in this Serrano Complex, and responded positively regarding the choice of an exclusive area for conservation. The Integrated Analysis of Landscape possible to identify the different forms of existing uses and occupations in Serrano Complex, have caused significant changes in space, especially on the plateau where vegetation was virtually replaced by human dwellings and cashew plantations. Through the maps of slope and environmental vulnerability was identified that areas with high slopes (gullies) are limiting factor for occupation by communities and therefore relevant and amenable to conservation, including by being Permanent Preservation Areas. These results, together, made possible to define a map of Priority Areas for Conservation in Serrano Complex, with three priority categories: low, medium and high. Therefore, the use of these additional criteria are relevant for the definition /designation of Priority Areas for Conservation

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Analisou–se o crescimento dos peixes, a composição das espécies e a produtividade de quatro policultivos (P75, P78, P87 e P207), visando melhorar o manejo e a produtividade pesqueira dos pequenos açudes (0,1–5,0ha) do Semi–Árido brasileiro. Simulou–se as condições desses açudes em viveiros com 120 e 5.000 m2 de área, sem renovação de água, utilizando moderada quantidade de adubo e fertilizante. A biomassa inicial variou de 75 a 207kg há–1, sendo formada por: tilápia do Nilo (Oreochromis niloticus), curimatã pacu (Prochilodus argenteus), carpa comum (Cyprinus carpio), tambaqui (Colossoma macropomum) e tucunaré (Cichla ocellaris). Os peixes apresentaram baixo crescimento (< 0,01g g–1d–1) após 75 dias de criação (P78 e 87). O crescimento do tambaqui, da tilápia e da curimatã foi reduzido após 53 dias (P75). Em moderada biomassa, o crescimento do tambaqui foi inferior ao da carpa e da curimatã (P207). A produtividade da tilápia atingiu 720 kg ha–1ano–1 (P78), sendo reduzida para 220 kg ha–1ano–1 devido ao processo reprodutivo (P75 e P207). A produtividade da carpa de 1.600 kg ha–1ano–1 foi superior a dos outros peixes (P87). A biomassa inicial de 75 kg ha–1 (60:30:4:3:3% de tilápia, tambaqui, carpa, curimatã e tucunaré, respectivamente) otimizou o crescimento e a produtividade dos peixes. A utilização de tilápias monossexadas e o fornecimento da alimentação suplementar ao tambaqui tornam–se imprescindíveis ao policultivo.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Pós-graduação em Agronomia (Proteção de Plantas) - FCA

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Pós-graduação em Agronomia (Proteção de Plantas) - FCA

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Em relação à fauna Culicidae, a Caatinga é um dos biomas mais desconhecidos do Brasil. Há carência de registro de ocorrência de culicídeos, bem como de estudos sobre as interações deles com o ambiente silvestre. Assim, o objetivo deste estudo foi investigar biodiversidade e aspectos ecológicos e epidemiológicos da fauna Culicidae em áreas de conservação do bioma Caatinga. Para isso foram consideradas duas unidades de conservação da Caatinga e realizados 19 levantamentos entomológicos mensais e consecutivos. Foram realizadas coletas de formas imaturas de mosquitos em bromélias, ocos de árvore e criadouros de solo, além da coleta de mosquitos adultos de hábitos diurno, crepuscular e noturno. Ao todo, entre mosquitos adultos e imaturos associados a habitats fitotelmatas, foram coletados 11.456 culicídeos distribuídos em 28 espécies, das quais 11 eram desconhecidas para a ciência. A fauna de imaturos coletados em bromélias e ocos de árvore interferiu na composição da fauna de mosquitos adultos e houve variações na abundância e nos padrões de diversidade de acordo com fitofisionomia do ambiente. Temperatura e umidade foram os parâmetros ambientais mais fortemente associados à abundância de culicídeos. Foram registradas novas ocorrências de anofelinos, coletados em criadouros de solo, ampliando a distribuição das espécies para o semiárido brasileiro. Este é um estudo pioneiro acerca da biodiversidade da fauna Culicidae em áreas de conservação da Caatinga que apresenta uma rica e desconhecida fauna de culicídeos, inédita para a ciência.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Environmental degradation is a global problem that particularly affects areas subject to seasonal climatic variations, such as the brazilian semiarid region, namely the Caatinga Domain. Combined with other negative factors, such as natural resource misuse and disorderly land occupation, the consequences of Environmental Degradation have challenged science in the quest for addressing the resulting social and environmental problems. Accordingly, Environmental Perception methodology, by analyzing the concepts, attitudes and values, (especially those pertaining to environmental conservation) represent an important tool in studies that address the relationship between the environment and human actions. Sustainability Indicators are also relevant tools to assess the possible causes and consequences of environmental problems. Among several Sustainability Indicators available, the PressuresState-Impact-Response (PSIR) method is an analytical tool that permits the grouping of factors affecting sustainability as well as their consequences for nature and human health, and thus indicate mitigating actions for society and the public authorities. From this perspective, three areas of Caatinga were studied in Rio Grande do Norte state: Seridó Ecological Station (ESEC), Municipality of Serra Negra do Norte; Private Natural Reserve Stoessel de Brito (PNRSB), Municipality of Jucurutu; and part of the Serra de Santana, Municipality of Tenente Laurentino Cruz. The areas are both legally protected and unprotected and subject to diferent management protocols, though their share the common characteristic of human misuse of natural resources. In this scenario, this thesis´ main goal was to introduce the rural communities into the conservation process, using the results of Environmental Perception of such communities, combined with the analysis of the sustainability of municipalities through PSIR. Information on Environmental Perception was obtained from primary and secondary data from previous studies carried out in the ESEC Seridó and PRNP Stoessel de Brito. Additional data was obtained through direct observation and interview forms applied to rural communities in the Municipality of Tenente Laurentino Cruz. The results showed that respondents possessed a broad knowledge regarding environmental degradation, its causes and consequences for the caatinga biome. PEIR analysis showed that environmental degradation was smaller in countries with protected areas, as compared to those without. The population´s knowledge about environmental degradation and their acceptance of conservation units, as showed by Environmental Perception Analysis, coupled with the results of PEIR, suggest that those attitudes may foster actions aimed at reduction of environmental degradation in the Caatinga domain

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The objective of this research was to evaluate the influence of the supply of five types of native and exotic cacti Brazilian semiarid northeast on the sensory characteristics of milk of Saanen goats. Five multiparous goats were used with nine weeks of lactation, average live weight of 50 kg ± 4 kg., confined and distributed in a Latin square design 5 x 5 with five experimental diets and five periods. Each period lasted 17 days, with 10 days of adaptation to the diets of the animals and seven days for the data collection. The treatments were defined based on dry matter consisted of: 47.33 to 50.12% of a cactus (“Xiquexique”, “Mandacaru”, “Facheiro” or two species of forage cactus “Miúda” or “Orelha de Elefante Mexicana”) more 18.78 to 19.79% hay of plant “Sabiá” and 31.10 to 32.89% of concentrate. There was not effect of the experimental diets in the physical and chemical composition of milk for fat, total solids and salts, which showed mean values of 3.24%; 11.30% and 0.66%, respectively. However the protein, lactose, nonfat dry extract and freezing point were affected by diets. In the profile of fatty acids was higher concentration of fatty short and medium chain fatty acids, however, there were not changes between treatments, except for the butyric acid (C4:0), with mean values of 4.24% (“Orelha de Elefante Mexicana”) to 6.05% (“Facheiro”). The diets also did not provide sensory changes in milk for the parameters: odor, flavor, aftertaste and overall assessment. The use of the five cactus in the diet of dairy goats do not influence the sensory characteristics and lipid profile of milk. The physical and chemical composition of milk was showed within the minimum requirements of current legislation, except for nonfat dry extract and freezing point.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Geastraceae is a monophyletic family included in the gomphoid-phalloid clade, it is composed only by two genus: Geastrum and Myriostoma. These genus are closely related in their morphology and phylogeny, both showing angiocarpic basidiomata, apical stoma, basidiospores passively released by the bellows mechanism and exoperidium dehiscent in rays, these genus are distinct by the number of stomas and pedicels. Because of dehiscense of exoperidium they are popularly known as “earthstars”. Usually they occur on decomposing leaf-litter and decaying wood. They are, thus, saprophytic, with rare exceptions of ectomycorrhizal species. Geastrum is the most diverse gasteroid genus in Brazil, with an estimated 51 records. However, there are large gaps in the geographic distribution and systematics studies about the Geastrum in this country, especially because of the characteristics found in the Brazilian territory (megadiverse, hotspots and continental size), which makes it a priority area for species inventory. Thus, this work was aimed at realizing inventory of species of Geastrum, which occur in Caatinga and Northeastern Atlantic Rainforest. At least two field expeditions were realized, during about four days on rainy season of 2013 and 2014 in the areas: Reserva Biológica de Guaribas, located in Atlantic Rainforest domain, Paraíba State and Reserva Ecológica Estadual Mata do Pau Ferro, located on “Brejos Paraibanos”, Paraíba State. Furthermore, specimens deposited in the Herbarium of the Universidade Federal do Rio Grande do Norte, which were collected in Parque Nacional Vale do Catimbau, Caatinga of Pernambuco State, were analyzed. The specimens were identified according to analysis of macro and micro morphology based on specific literature. Approximately 400 basidiomata, distributed in 73 exsiccates were analyzed. 21 species were identified, 19 are in specie level, which two are proposed to new species. (Geastrum magnosporum sp. nov. e G. pusillupilosum sp. nov.) and two in genera level (sp. e aff.). We emphasize one new record for Brazil, 12 new records for Paraíba State, four new records for semiarid region in Brazil and six new records to Atlantic Rainforest relicts “Brejo de Altitude”. So, the results improved the knowledge about Geastrum in Paraíba State by 200%, 24 % in Brazilian semiarid region and 55% in Atlantic Rainforest relicts “Brejo de Altitude”, evincing that Northeastern Brazil has high species richness.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The cactus pear has become over the years an important forage alternative for brazilian semiarid region, especially during long periods of drought. Despite its importance for agriculture, its cultivation has dispensed basic crop practices and fundamentals technical-scientific basis about its climatic requirements. Thus, the main objective of this study was to elaborate the agroclimatic zoning of cactus pear (Opuntia sp.) for the state of Paraíba. The agroclimatic zoning of cactus pear was based on climatic indicators outlined in the literature and climatological data of precipitation and temperature (mean, maximum, and minimum) from 97 locations in the state of Paraíba. According to the results, the region of ‘Borborema’ is the most favorable for the cultivation of cactus pear. The regions of ‘Agreste’, ‘Sertão’, and coastal part of Litoral may be used but with restrictions. However, the cultivation of cactus pear is recommended throughout the state of Paraíba, except the coastal part of the Litoral and the region around Areia. In both cases, the inability is due to excessive precipitation.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Reservoirs are artificial ecosystems intermediate between rivers and lakes widely used in the Brazilian semiarid region as a way to provide water supply due to the said region’s water scarcity. The use of water from these supply sources for multiple uses, along with occupation and utilization of its riparian zone without proper management, directly influences the increased nutrient flow into aquatic environments, there with contributing to the acceleration of eutrophication. The semi-arid region is characterized by peculiar weather conditions, such as severe evaporation, high temperatures with little variation throughout the year and long water residence time, making it susceptible to prolonged drought occurrence, which tends to concentrate the nutrients in reservoirs, which favors the development of eutrophic conditions. Moreover, it is common soil use and occupation by carrying out activities with potential environmental impact on natural resources such as agriculture, livestock farming and lack of sanitation. The aim of this study is both to evaluate the water quality of the Cruzeta Reservoir, located in the semiarid region of Rio Grande do Norte, during a prolonged drought period, and assess the quality of its riparian zone soil under different uses, by monitoring physical-chemical variables. Along the prolonged drought, high levels of turbidity, suspended solids, nutrients and chlorophyll a were verified as present, therefore featuring low water quality. In the riparian zone of Cruzeta Reservoir, the areas under use of agriculture and livestock farming appeared as one of the main diffuse sources of nutrients to the said reservoir, featuring the highest levels of phosphorus and nitrogen in the soil, originated from decomposition of animal excreta and from the use of fertilizers, creating a tendency to increased eutrophication of such water supply source. The indicators of water and soil quality are useful for monitoring and evaluating the conservation status of natural resources, allowing the control and mitigation of the reservoir eutrophication process. This study confirmed the hypothesis that the reduction of water level, resulting from prolonged drought event, aggravates the symptoms of eutrophication; and also that using the soil under severalways modifies the physic chemical properties of the soil, having livestock farming and agriculture as the usages with greatest potential towards yielding P and N to the aquatic environment.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Human activities alter soil features, causing the deterioration of its quality. Land use and occupation in drainage basins of water supply reservoirs can change the environmental soil quality and, thus, lead to the expansion of the soil potential of being a diffuse pollution source. In the Brazilian semiarid region, the soils are generally shallow with high susceptibility to erosion, favoring the sediment and nutrients input into the superficial waterbodies, contributing to the eutrophication process. Moreover, this region has high temperatures and high evapotranspiration rates, that are generally higher than the precipitation rates, causing a negative hydric balance and big volume losses by evaporation. The water volume reduction increases the nutrients’ concentration and, therefore, exacerbates the eutrophication process, deteriorating the water quality. Thereby, we hypothesized that the eutrophication process of semiarid reservoirs is intensified both by the extreme climatic events of prolonged drought, and by the diffuse pollution due to the basin land use and occupation. The study aimed to test whether the land use and occupation activities of the basin and the severe drought events intensify the eutrophication process of a semiarid tropical reservoir. To verify the influence of human activities carried out in the water supply of drainage basin on the soil quality and the eutrophication process, we conducted the mapping of the kind of use and occupation, as well the calculation of erosion for each activity and the soil quality evaluation of the riparian zone and water quality of the water supply. For the water analyses, the samplings were carried out monthly in the deeper point, near dam. For the soil, deformed composite samples were taken for the physical and chemical attributes analysis, according to the identified land use and occupation classes. The results showed that extreme droughts drastically reduces the water volume and elevates the nutrients concentration, contributing, thus, to a bigger degradation of water quality. Furthermore, we verified that human activities in the drainage basin promote the diffuse pollution, by increasing the soil susceptibility to erosion and nutrients contents. Summarizing, our results support the investigated hypothesis that activities of land use and occupation and extreme drought generate a combined effect that provide the intensification of eutrophication process of semiarid reservoirs.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Eutrophication is the most common cause of water quality degradation in the world. This process occurs by excessive nutrients inputs, nitrogen and phosphorus, to the aquatic systems resulting in algal and cyanobacterial blooms. In shallow lakes these effects are pronounced due to the higher interaction of the lake with watershed, air and sediment. There are innumerous restoration techniques of eutrophied lakes with a range of successful results but there is only one case of successful lake restoration in Brazil: Paranoá Lake in Brasília city. The Brazilian semiarid region has many artificial lakes, named açudes, which are mostly eutrophic and shallow lakes. The eutrophication in these lakes is reported and the phytoplankton community is dominated by potentially toxic cyanobacteria species, mainly Cylindrospermopsis raciborskii. The aim of this thesis is to test techniques for water quality management which can be easily applied in Brazilian semiarid lakes. Results from a laboratory experiment suggest that the addition of a phosphorus sorbent clay associated with an aluminium based coagulant is an effective technique in removing soluble reactive phosphorus and reducing C. raciborskii growth rate – cyanobacteria potentially toxic dominant in reservoirs of Brazilian semiarid – but this effect is dependent on the biomass in the application moment. Results from a field experiment in mesocosm in a eutrophied lake showed that the addition of aluminium based coagulant and removal of benthivorous fish is more efficient in removing total phosphorus and chlorophyll-a from water column than the isolated application of one of the techniques. Lastly, laboratory tests showed that aluminium based coagulant exhibited good performance in removing turbidity and total phosphorus from water of six reservoirs but the efficiency was reduced by algal biomass and pH. The results of this study showed that the improvement in water quality of eutrophied reservoirs in semiarid region is possible through internal loading control by phosphorus precipitation and inactivation in sediments or inhibition of phosphorus release by benthivorous fishes, and also that these results show are additives in water quality improvement.