Silvio Carlos Rodrigues

Timing of Erosion and Satellite Data: A Multi-resolution Approach to Soil Erosion Risk Mapping

Abstract Erosion reduces soil productivity and causes negative downstream impacts. Erosion processes occur on areas with erodible soils and sloping terrain when high-intensity rainfall coincides with limited vegetation cover. Timing of erosion events has implications on the selection of satellite imagery, used to describe spatial patterns of protective vegetation cover. This study proposes a method for erosion risk mapping with multi-temporal and multi-resolution satellite data. The specific objectives of the study are: (1) to determine when during the year erosion risk is highest using coarse-resolution data, and (2) to assess the optimal timing of available medium-resolution images to spatially represent vegetation cover during the high erosion risk period. Analyses were performed for a 100-km2 pasture area in the Brazilian Cerrados. The first objective was studied by qualitatively comparing three-hourly TRMM rainfall estimates with MODIS NDVI time series for one full year (August 2002–August 2003). November and December were identified as the months with highest erosion risk. The second objective was examined with a time series of six available ASTER images acquired in the same year. Persistent cloud cover limited image acquisition during high erosion risk periods. For each ASTER image the NDVI was calculated and classified into five equally sized classes. Low NDVI was related to high erosion risk and vice versa. A DEM was used to set approximately flat zones to very low erosion risk. The six resulting risk maps were compared with erosion features, visually interpreted from a fine-resolution QuickBird image. Results from the October ASTER image gave highest accuracy (84%), showing that erosion risk mapping in the Brazilian Cerrados can best be performed with images acquired shortly before the first erosion events. The presented approach that uses coarse-resolution temporal data for determining erosion periods and medium-resolution data for effective erosion risk mapping is fast and straightforward. It shows good potential for successful application in other areas with high spatial and temporal variability of vegetation cover.

Automatic identification of erosion gullies with ASTER imagery in the Brazilian Cerrados

Gully erosion is a serious problem at many locations worldwide, but little is known about its importance at large spatial scales. The remote sensing contribution for the spatial assessment of gullies has thus far been confined to visual image interpretation. The current study was conducted to determine whether automatic classification of optical ASTER imagery could accurately discern permanent erosion gullies in the Brazilian Cerrados. A maximum likelihood classifier (MLC) was trained with two classes, gullies and non‐gullies, and applied to images of March (wet season) and August (dry season). Moreover, a bi‐temporal classification was performed by labelling a pixel as gully when both for the March and August image it was classified as such. Validation was done with a gully map obtained from a panchromatic QuickBird image and field data. For mono‐temporal classification, the March image performed much better than the August image, because spectral differences are more pronounced during the wet season. Based on spatial analysis of output maps, the bi‐temporal classification performed best in identifying gullies, as user’s accuracy was above 90%, while two of 17 actual gullies were not detected and two small locations were erroneously identified as gully. The combination of ASTER bands 1, 2, 3, and 4 gave highest accuracies. It is concluded that accurate automatic identification of permanent gullies is possible with optical satellite data. Because the Cerrados occupy a vast area, it is expected that the approach presented could be applied to larger areas with similar characteristics.

Monitoramento de erosão laminar em diferentes usos da terra, Uberlândia - MG

O processo erosivo quando agravado pela acao do homem traz problemas economicos e ambientais, pois influenciam no nivel de estabilidade do ambiente. Este trabalho foi desenvolvido na Fazenda Experimental do Gloria/UFU com o objetivo de analisar e comparar a diferenca do processo de erosao pluvial entre sete tipos de usos da terra. Para isso, foram coletados dados de umidade, escoamento superficial, transporte de sedimentos e ainda imagens da cobertura foliar de cada parcela para a fotocomparacao. Para o experimento foram utilizadas parcelas experimentais ou parcelas de erosao, com inclinacao de 5° e uma calha de captacao da agua em sua parte inferior, permitindo assim que fosse coletado todo o material erodido. Como primeiro resultado foi visto que qualquer tipo de cobertura vegetal auxilia na contencao da erosao, com a interceptacao das gotas da chuva e da radiacao solar por parte das folhas. E visivel tambem que com o escoamento superficial sao transportadas particulas de solo e nutrientes e desta forma, os nutrientes presentes nas camadas superiores do solo sao perdidos facilmente por erosao.

Acúmulo de serrapilheira em fragmentos de mata mesofítica e cerrado stricto senso em Uberlândia-MG

The sustainable way to explore the natural resources according to the environmental fragility is necessary to understand the dynamic processes which evolve the diversity of natural aspects. In this way the present research had for objective collect, manage and present data about the organic matter accumulation, as well as data related to the soil humidity, rainfall, wind and temperature in plots located in two different fragments of Mesophytic Forest and Cerrado (Savanna) at Fazenda Experimental of Gloria, looking for understand the local environmental evolution. The experiments were carried out between July/2007 and January/2008 in two phases: the field work when the measurements were carried out and at the same time the lab work when the material was treated and analyzed. The climate data was performed at a mini meteorological station located at the experiment field and the soil humidity was measured using a Thetra Probe device performed near the collector.

RELAÇOES ENTRE POTENCIAL MATRICIAL NO SOLO E COBERTURA VEGETAL EM UMA ESTAÇÃO EXPERIMENTAL, UBERLÂNDIA - MG

Faz-se neste artigo uma analise sobre a relacao entre o potencial matricial e a cobertura vegetal em uma estacao experimental na Fazenda do Gloria, Uberlândia- MG, com base nos dados obtidos nos tensiometros e na fotocomparacao. Foram adotados os seguintes procedimentos: a. Construcao de duas parcelas de 10 m2 cada, uma com Solo Exposto (SE) e outra com Geotexteis e Gramineas (SG); b. A analise granulometrica dos sedimentos foi baseada na proposta da EMBRAPA; c. Monitoramento de duas baterias de tensiometros nas parcelas com solo exposto e com geotexteis em diferentes profundidades (15, 30, 80 e 120 cm), com o auxilio de um tensimetro digital INFIELD 5; e d. Fotocomparacao com classificacao supervisionada usando software de sensoriamento remoto. Os resultados foram divididos em tres fases: 1. na fase 1, a ocupacao da cobertura vegetal variou entre 0 a 6,4%, destacando-se o tensiometro de 120 cm cm na parcela com geotexteis, que atingiu -20 kPa; 2. na fase 2, com uma taxa de ocupacao variando entre 15,2% a 59,4 % na parcela com geotexteis e gramineas, o potencial matricial chegou a -32,4 kPa na profundidade de 15 cm; e 3. na fase 3, com uma taxa de ocupacao da graminea entre 63,9% a 100% , cita-se o tensiometro de 30 cm, que chegou a -67 kPa.

O MÉTODO DE ANÁLISE HIERÁRQUICA - AHP - COMO AUXÍLIO NA DETERMINAÇÃO DA VULNERABILIDADE AMBIENTAL DA BACIA HIDROGRÁFICA DO RIO PIEDADE (MG)

Resumo: A determinacao da vulnerabilidade ambiental permite avaliar a condicao de risco da area estudada a processos geoambientais, tais como erosao, contaminacao dos solos, dos recursos hidricos, perda de aproveitamento agricola, dentre outros. Dando suporte ao estudo da vulnerabilidade ambiental, o AHP - Analystic Hierarchy Process - Processo Analitico Hierarquico, consiste na criacao de uma hierarquia de decisao que permite obter uma visao global das relacoes inerentes ao processo. Foi necessario executar, individualmente, a comparacao par a par e o cruzamento de quatro criterios de analises considerados decisivos para a determinacao da vulnerabilidade: declividade, uso e ocupacao da terra, pedologia e geologia. Areas de preparo de plantio ou solo exposto mostraram-se mais favoraveis a vulnerabilidade do ambiente, seguidos pelas areas de declividades superiores a 30%. As areas fracamente vulneraveis encontraram-se preferencialmente proximas ao rio Piedade, em seu medio curso, e tambem na porcao noroeste da bacia. Este fato deve-se principalmente a geologia destas areas, que e desfavoravel a ocorrencia de processos contribuintes a vulnerabilidade. O Mapa de Vulnerabilidade Ambiental da bacia hidrografica do rio Piedade, produto final do processamento do metodo AHP, mostra imparcialidade nos resultados e minimiza erros de julgamento durante o processo. Palavras-Chave: Vulnerabilidade Ambiental; AHP; Geoprocessamento; Bacia Hidrografica.

ASPECTOS GEOLÓGICO-GEOMORFOLÓGICOS DO PARQUE ESTADUAL DO IBITIPOCA/ MG: BASE PARA O ENTENDIMENTO DO SEU GEOPATRIMÔNIO

O Parque Estadual do Ibitipoca (PEI) e a unidade de conservacao estadual mais visitada no Estado de Minas Gerais, de acordo com dados dos IEF – Instituto Estadual de Florestas (2012) e essa estatistica vem refletir a grande beleza cenica do seu geopatrimonio, tais como grutas, quedas d’agua, praias fluviais, ponte de pedra etc. O objetivo desse estudo e efetuar a caracterizacao da geologia e do relevo local, de forma a compreender o geopatrimonio la existente. Espera-se que as informacoes aqui disponibilizadas sejam, no futuro, adaptadas e repassadas aos visitantes do parque, promovendo nao apenas a contemplacao, mas o entendimento do geopatrimonio, numa perspectiva de valorizacao dessa vertente da natureza.

The use of geotechnologies in the landscape fragility analysis of medium lower Araguari river basin, Brazil

This paper presents the mapping of environmental fragility of Medium Lower Araguari River Basin,Minas Gerais State - Brazil. This was possible from the analysis of the various environment variablesthat complete the basin system, such as landforms, rocks, soils, land use and vegetable coverage. It wasused as methodological basis the General Systems Theory, the Landscape Ecology and EnvironmentalGeomorphology, together with the application of geospatial technologies and GIS. From the systemicand holistic analysis of the landscape, it was possible to produce various cartographic maps to representthe environmental aspects of the study area, enabling the correlation and the generation of the potentialand emerging fragility maps.The main objective of this work is to test a methodology for assessing thenatural fragility of erosion occurrence by correlating variables in a GIS environment. In this sense, themethod of Weighted Overlay was used in an GIS environment for mapping parameters. The resultsgenerate 2 types of approach, one dealing with the potential of the basin natural weakness in whichwe obtained a distribution of 39.30% of the total area of the basin in the Lower class of fragility, and29.20% Medium Class of Fragility and 26.37% for the High Class of Fragility. A second analysis isperformed by inserting human activities that affect and improve the development of erosion processes,and showed that predominate in the watershed classes of Medium Fragility with 47.35% of the totalarea and 39.28% of the total area with Low Fragility.

Potencial geoturístico das quedas d'água de Indianópolis-MG para o público escolar: unindo ciência e contemplação

The city of Indianopolis is located in the Mineiro Triangle and is recognized by the beauty and diversity of its waterfalls. These attributes have led us to study such city, searching for the identification of the geotouristic potential of its waterfalls for educational activities, as well as select one which shows to be the most suitable for the scholars. The methodology used in the beginning involved bibliographical research about the theme, field work in the area of the waterfalls and, finally, office work, a moment in which data were interpreted and crossed. From the methodology used one has the conclusion that the waterfalls of Indianopolis present a great potential to be used by geotourism, and also the Salto de Furnas (Furnass leap) has presented the Best place for educational activities, due to, among other factors, the facility to access it, lithoestratigraphic richness, preservation state, etc.

Educação ambiental e o ecoturismo na Serra da Bodoquena em Mato Grosso do Sul

The study of the interrelationship of ecotourism with environmental education in the region of Serra da Bodoquena, state of Mato Grosso do Sul - Brazil, specifically in the cities of Bonito and Jardim, is the subject of this article. The relevance of the study is justified due to the fact of Serra da Bodoquena is located in Rio Miranda Hydrographic Basin, occupying a strategic position for connection of biomes: Atlantic Forest, Cerrado and Pantanal. The field research showed that diversification of sites observed can be interpreted through observation and experimentation by experts from different fields of knowledge, being a vast field for the development of numerous studies. Then, by on-site survey of the main environmental characteristics of tourist attractions: Buraco das Araras, Gruta do Lago Azul, Baia Bonita and Rio Formoso, proceeded to the analysis of practice of ecotourism and its educational aspect. It is therefore the need for intensification of educational actions, especially for tourist guides in order to be the main inductors and distributors of information relating to the environment, as well as the realization of attractive studies related to journey offered in attractive, with their assessment of the educational potential of mapping of characteristics and suitability of their different visitors.