6,536 research outputs found

    Áreas frágeis no Brasil: subsídios à legislação ambiental.

    Get PDF
    Resumo: O presente trabalho traz uma abordagem sobre a conceituação de áreas frágeis, contextualizando-as e informando sobre os tipos, características e localização na paisagem, como uma forma de contribuir para o aperfeiçoamento e a evolução da legislação ambiental do país. Das oito categorias de áreas frágeis abordadas neste trabalho, seis delas encontram-se amparadas pela legislação, apesar de não serem devidamente respeitadas, seja por falta de consciência da sociedade seja pela falta de fiscalização adequada por parte dos órgãos responsáveis. As duas categorias restantes (áreas de recarga de aquíferos e arenização e desertificação), embora ainda não amparadas pela legislação vigente, merecem cuidados semelhantes às demais, não só pela magnitude de suas influências no contexto socio-econômico e ambiental que apresentam, mas principalmente pelas fortes restrições de uso agrícola. De forma conclusiva, este trabalho propõe uma contribuição, direcionada para o aperfeiçoamento e evolução do Código Florestal Brasileiro, considerando os biomas e as particularidades regionais, fundamentada em resultados de pesquisa que, necessariamente, fornecerão as bases para a conservação e sustentabilidade das áreas aqui denominadas frágeis.bitstream/item/48747/1/documentos-87.pd

    Considerações técnicas sobre a aplicação de tecnologias de irrigação em áreas de recarga do Aqüífero Guarani.

    Get PDF
    As áreas de recarga do Aqüífero Guarani são caracterizadas por solos de textura arenosa, com baixa capacidade de armazenamento de água, alta velocidade de infiltração de água e grande suscetibilidade à erosão, exigindo que, para a operação de sistemas de irrigação nessas áreas, sejam considerados diversos aspectos técnicos para minimizar o risco de contaminação das águas subterrâneas, tais como a determinação do período de irrigação e de controle rigoroso da água, além de nutrientes e agrotóxicos aplicados

    Hydrological and erosion response at micro-plot to -catchment scale following forest wildfire, north-central Portugal

    Get PDF
    Wildfires can have important impacts on hydrological and soil erosion processes, due to the destruction of vegetation cover and changes to soil properties. According to Shakesby and Doerr (2006), these wildfire effects are: i) much better known at small spatial scales (especially erosion plots) than at the scale of catchments; ii) much better studied with respect to overland flow and streamflow (and, then, especially peak discharges) than to soil erosion. Following up on a precursor project studying runoff generation and the associated soil losses from micro-plot to slope-scale in Portuguese eucalypt forests, the EROSFIRE-II project addresses the connectivity of these processes across hillslopes as well as within the channel network. This is done in the Colmeal study area in central Portugal, where the outlet of an entirely burnt catchment of roughly 10 ha was instrumented with a gauging station continuously recording water level and tubidity, and five slopes were each equipped with 4 runoff plots of < 0,5 m2 (“micro-plot”) and 4 slope-scale plots as well as 1 slope-scale sediment fence. Starting one month after the August 2008 wildfire, the plots were monitored at 1- to 2-weekly intervals, depending on the occurrence of rainfall. The gauging station became operational at the end of November 2008, since the in-situ construction of an H-flume required several weeks. A preliminary analysis of the data collected till the end of 2008, focusing on two slopes with contrasting slope lengths as well as the gauging station: revealed clear differences in runoff and erosion between: (i) the micro-plot and slope-scale plots on the same hillslope; (ii) the two slopes; (iii) an initial dry period and a subsequent much wetter period; (iv) the slopes and the catchment-scale, also depending on the sampling period. These results suggest that the different processes govern the hydrological and erosion response at different spatial scales as well as for different periods, with soil water repellency playing a role during the initial post-fire period. The current presentation will review these preliminary results based on the data collected during the first year after the wildfire

    Cephalopod identification keys to Histioteuthidae, Cranchiidae and Octopodiformes of the Azores, with an updated check-list

    Get PDF
    This work is a combination of unpublished cephalopod identification keys compiled by Malcolm R. Clarke for the Azores region (Central North Atlantic) and a review of the Octopoda of the Azores by João Gonçalves (MSc Thesis 1993, originally written in Portuguese), updated with recent literature. A regional list of cephalopod species of the Azores is provided totaling 83 species, with identification keys for: i) Histioteuthidae, including five species; ii) Cranchiidae, including eleven species; and iii) Octopodiformes, including Vampyroteuthis infernalis Chun, 1903 (Order Vampyromorpha), three cirrate and fourteen incirrate octopuses. Separate keys are given for Octopodiformes species. The revisions are discussed and a more detailed description of Octopoda species is included.Oma – Observatório do Mar dos Açores ; MARE – Centro de Ciências do Mar e do Ambiente ; IMAR – Instituto do Mar ; DOP – Departamento de Oceanografia e Pescas ; Universidade dos Açoresinfo:eu-repo/semantics/publishedVersio

    Flood hazard mapping by integrating airborne laser scanning data, high resolution images and large scale maps: a case study

    Get PDF
    The assessment and management of flood risks framework impose the mapping of flood hazard in potential flood risks areas. Floods in urban environments may happen due to rainfall extreme events and be exacerbated by saturated or impervious surfaces. Flood risk is greater in urban areas. (...

    Proteolysis in model portuguese cheeses: Effects of rennet and starter culture

    Get PDF
    To shed further light onto the mechanisms of proteolysis that prevail throughout ripening of Portuguese cheeses, model cheeses were manufactured from bovine milk, following as much as possible traditional manufacture practices – using either animal or plant rennet. The individual role upon proteolysis of two (wild) strains of lactic acid bacteria – viz. Lactococcus lactis and Lactobacillus brevis, which are normally found to high viable numbers in said cheeses, was also considered, either as single or mixed cultures. Our experimental results confirmed the influence of rennet on the proteolysis extent, but not on proteolysis depth. On the other hand, the aforementioned strains clearly improved release of medium- and small-sized peptides, and contributed as well to the free amino acid pool in cheese

    Runoff and erosion at the micro-plot and slope scale in a small burnt catchment, central Portugal

    Get PDF
    Wildfires can have important impacts on hydrological processes and soil erosion in forest catchments, due to the destruction of vegetation cover and changes to soil properties. However, the processes involved are non-linear and not fully understood. This has severely limited the understanding on the impacts of wildfires, especially in the up-scaling from hillslopes to catchments; in consequence, current models are poorly adapted for burnt forest conditions. The objective of this presentation is to give an overview of the hydrological response and sediment yield from the micro-plot to slope scale, in the first year following a wildfire (2008/2009) that burnt an entire catchment nearby the Colmeal village, central Portugal. The overview will focus on three slopes inside the catchment, with samples including: • Runoff at micro-plot scale (12 bounded plots) and slope scale (12 open plots); • Sediments and Organic Matter loss at micro-plot scale (12 bounded plots) and slope scale (12 open plots plus 3 Sediment fences); • Rainfall and Soil moisture data; • Soil Water Repellency and Ground Cover data. The analysis of the first year following the wildfire clearly shows the complexity of runoff generation and the associated sediment transport in recently burnt areas, with pronounced differences between hillslopes and across spatial scales as well as with marked variations through time. This work was performed in the framework of the EROSFIRE-II project (PTDC/AGR-CFL/70968/2006) which has as overall aim to predict soil erosion risk in recently burnt forest areas, including common post-fire forest management practices; the project focuses on the simultaneous measurement of runoff and soil erosion at multiple spatial scales.The results to be presented in this session are expected to show how sediment is generated, transported and exported in the Colmeal watershed; and contribute to understand and simulate erosion processes in burnt catchments, including for model development and evaluation

    Variscan deformation of the Hesperian massif in the Lousã mountain range (central Portugal)

    Get PDF
    [Abstract] The occidental region of the Central-Iberian Zone of the Variscan Iberian massif, in the central part of Portugal (Lousã mountain range), has a Variscan tectonostructural organization as the one recognized in the occidental border of the massif, in the Porto-Coimbra-Tomar shear zone. In the Iberian massif we can observe neo-proterozoic metasediments of the “Complexo Xisto-Grauváquico”, and important metasedimentary outcrops of Late Palaeozoic (Ordovician, Silurian and lower Devonian) rocks. Both are affected by the first regional variscan deformation phase (FH1), and later refolded by the second variscan deformation phase (FH2). This second regional variscan phase has a penetrative effect in the massif and develops a dextral, north-south, strike-slip faulting, associated with transpressive kinematic deformation (like a Riedel model) similar to the Porto-Coimbra-Tomar shear zone. Some geological examples observed and studied in the Lousã region are showed and discussed

    Importância das áreas protegidas (por lei) na gestão ambiental sustentável.

    Get PDF
    As áreas protegidas (por lei) são naturalmente frágeis e quando submetidas à ação antrópica inadequada pode resultar em desequilíbrios, nos diversos compartimentos ambientais, tais como água, solo, ar, plantas e demais organismos que integram os ecossistemas. Como objetivo, visou-se apresentar uma abordagem sobre áreas protegidas (frágeis), contextualizando-as sobre os tipos, características e localização na paisagem, aspectos estes fundamentais para o planejamento e gestão sustentáveis, com qualidade ambiental. Os resultados corresponderam a seis categorias de áreas protegidas:a) Topos de morros, encostas e escarpas de serras (bordas de depressões); b) Nascentes de cursos d?água; c) Margens de cursos d?água, várzeas e leitos inundáveis; d) Lagos, lagoas e lagunas; e) Mangues; e f) Restingas. Ficou evidente que a maioria das áreas protegidas possui conexão direta com os recursos hídricos, o que reforça a importância deste trabalho como base para planejamento e gestão sustentáveis, além de ressaltar a necessidade do cumprimento da legislação ambiental. Como recomendação, deve ser priorizada a implantação efetiva de um programa de educação ambiental; fiscalização oficial contínua, a fim de identificar inconformidades quanto à legislação ou adequação de uso; adoção de planos de uso e manejo sustentáveis, protegendo os recursos naturais e biodiversidade.Livro Eletrônic
    corecore