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Fire hazard and susceptibility to desertification: a territorial approach in NE Portugal

Figueiredo, Tomás de; Fonseca, Felícia; Pinheiro, Helena
Fonte: RISCOS - Associação Portuguesa de Riscos, Prevenção e Segurança Publicador: RISCOS - Associação Portuguesa de Riscos, Prevenção e Segurança
Tipo: Conferência ou Objeto de Conferência
ENG
Relevância na Pesquisa
37.58%
Continental Portugal endures an increase in desertification susceptibility, a process accelerated by soil degradation and wildfires. This work aims at discussing outcomes of a research, at territorial scale, on fire hazard relations with soil degradation and desertification susceptibility in NE Portugal, specifically in Bragança District, based on GIS desertification susceptibility fire hazard, land cover and soil degradation maps. High and very high fire hazard prevails in near 2/3 of the territory and around 3/4 are susceptible to desertification,falling in the semi-arid and dry sub-humid climatic domains; about 20% of the former fall in the semi-arid. In around 3/4 of the area with high/very high fire hazard soils depict severe or worse degradation status, and in around 40% they are covered by scrublands, where fuel stock is high and social control is negligible. This negative picture asks for measures towards effective soil protection, a key resource for territorial sustainability.

Cariri paraibano : do silêncio do lugar à desertificação

Souza, Bartolomeu Israel de
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Tese de Doutorado Formato: application/pdf
POR
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No presente estudo, tomando por base o processo histórico de ocupação e povoamento do Cariri, a análise qualitativa da vegetação, através de bio-indicadores (diversidade, densidade e estratos) e o uso de técnicas de sensoriamento remoto e geoprocessamento, foi efetuado o mapeamento da desertificação na região. Entre os resultados encontrados, foi verificado que: atualmente (2005/2006), a área atingida por esse processo, em todos os níveis analisados (Moderado, Grave e Muito Grave), corresponde a 77,4% de toda a região; de 1989 a 2005/2006, houve um aumento de cerca de 14,6% em relação a esse tipo de degradação; no período pesquisado, o maior crescimento da desertificação ocorreu no Cariri Ocidental; na identificação e quantificação das áreas desertificadas, o uso de imagens de satélite próximas do final da estação chuvosa na região apresentou respostas mais satisfatórias que as imagens da estação seca; a análise das imagens de satélite através do uso da classificação Não Supervisionada respondeu melhor ao que foi verificado em campo que o IVDN. As áreas onde o processo de desertificação está mais acentuado e concentrado localizam-se nas terras próximas das maiores bacias hidrográficas da região (Paraíba e Taperoá)...

Reabilitação de quatro edifícios no centro histórico da cidade de Viseu

Rodrigues, Sérgio Joaquim Teixeira
Fonte: Universidade Católica Portuguesa Publicador: Universidade Católica Portuguesa
Tipo: Dissertação de Mestrado
Publicado em 31/10/2014 POR
Relevância na Pesquisa
27.38%
No presente relatório, pretende-se expor o percurso realizado ao longo do estágio em regime de atelier. O percurso implicou uma integração numa equipa de trabalho multidisciplinar, com a participação num projeto de reabilitação. A intervenção insidiu num conjunto de quatro edifícios situados em pleno Centro Histórico da Cidade de Viseu. O relatório foi estruturado em duas fases. Na primeira foi realizada uma reflexão teórica sobre a temática que envolve a reabilitação e na segunda apresentada a descrição das atividades e funções desenvolvidas em atelier, apoiadas por um levantamento exaustivo e documentado. O projeto relaciona a problemática da desertificação dos Centros Históricos com uma intervenção pontual, num conjunto edificado do Centro Histórico de Viseu. O programa da intervenção estabelecido previa a reconversão dos quatro edifícios, outrora usados como escritórios com exceção do nº45 que era habitação, numa habitação e num modelo de alojamento misto - hostel e de arrendamento. A realização deste estágio revelou-se de uma enorme importância, não só pela fonte de aprendizagem que proporcionou sobre as complexidades do habitat humano resolvendo desafios numa sociedade em constante mudança...

Desertification in Portugal: causes, consequences and possible solutions

Branco, João; Oliveira, Márcia; Ferreira, Ricardo; Póvoa, Orlanda
Fonte: Repositório Comum de Portugal Publicador: Repositório Comum de Portugal
Tipo: Artigo de Revista Científica
Publicado em 10/01/2014 ENG
Relevância na Pesquisa
37.64%
Although desertification is not a new problem, world-wide population awareness is increasing. This problem has a greater impact in developing countries, where subsistence agriculture leads to very serious consequences as famine and sub-nutrition. However, desertification also affects the developed ones, because of, among other factors, unsustainable practices in the Agriculture and Forestry sectors combined with poor land management and weak policies. Without proper action, over 50 million people worldwide could be displaced by desertification and land degradation in the next decade. This paper, through a literature review, will approach the problem of desertification, with a special focus on the Portuguese case, its causes and consequences as well as some possible solutions. We conclude that driving forces of desertification can be separated into climate variations and Human activities and that its main consequences are environmental and social-economic. We also point out that, though technical solutions are abundant, part of the solution to this issue relays on attracting population back to the country side, involving the local people on the solution finding processes and increase the social benefits of exploring scarce resources...

Quantitative Assessment of Desertification Using Landsat Data on a Regional Scale – A Case Study in the Ordos Plateau, China

Xu, Duanyang; Kang, Xiangwu; Qiu, Dongsheng; Zhuang, Dafang; Pan, Jianjun
Fonte: Molecular Diversity Preservation International (MDPI) Publicador: Molecular Diversity Preservation International (MDPI)
Tipo: Artigo de Revista Científica
Publicado em 12/03/2009 EN
Relevância na Pesquisa
27.79%
Desertification is a serious threat to the ecological environment and social economy in our world and there is a pressing need to develop a reasonable and reproducible method to assess it at different scales. In this paper, the Ordos Plateau in China was selected as the research region and a quantitative method for desertification assessment was developed by using Landsat MSS and TM/ETM+ data on a regional scale. In this method, NDVI, MSDI and land surface albedo were selected as assessment indicators of desertification to represent land surface conditions from vegetation biomass, landscape pattern and micrometeorology. Based on considering the effects of vegetation type and time of images acquired on assessment indictors, assessing rule sets were built and a decision tree approach was used to assess desertification of Ordos Plateau in 1980, 1990 and 2000. The average overall accuracy of three periods was higher than 90%. The results showed that although some local places of Ordos Plateau experienced an expanding trend of desertification, the trend of desertification of Ordos Plateau was an overall decrease in from 1980 to 2000. By analyzing the causes of desertification processes, it was found that climate change could benefit for the reversion of desertification from 1980 to 1990 at a regional scale and human activities might explain the expansion of desertification in this period; however human conservation activities were the main driving factor that induced the reversion of desertification from 1990 to 2000.

How Sustainable Is Government-Sponsored Desertification Rehabilitation in China? Behavior of Households to Changes in Environmental Policies

Liu, Ning; Zhou, Lihua; Hauger, J. Scott
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 31/10/2013 EN
Relevância na Pesquisa
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This paper undertakes a direct, comprehensive assessment of the long-term sustainability of desertification rehabilitation in China under a plausible but worst case scenario where governmental interventions, in the form of payments for environmental services (PES), will cease. The analysis is based on household behavior as well as experimental data. Our econometric results highlight the main obstacles to the sustainability of rehabilitation programs subsequent to cessation of government intervention, including specific shortfalls in households’ preference for a free ride, budget constraints, attitudes, tolerance of and responsibility for desertification, and dissatisfaction with governmental actions. We conclude that desertification rehabilitation is not sustainable in China without continued governmental intervention. The results of this study are intended to support policy makers as they consider future directions for rehabilitation sustainability.

Fuzzy Comprehensive Evaluation-Based Disaster Risk Assessment of Desertification in Horqin Sand Land, China

Wang, Yongfang; Zhang, Jiquan; Guo, Enliang; Sun, Zhongyi
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.73%
Desertification is a typical disaster risk event in which human settlements and living environments are destroyed. Desertification Disaster Risk Assessment can control and prevent the occurrence and development of desertification disasters and reduce their adverse influence on human society. This study presents the methodology and procedure for risk assessment and zoning of desertification disasters in Horqin Sand Land. Based on natural disaster risk theory and the desertification disaster formation mechanism, the Desertification Disaster Risk Index (DDRI) combined hazard, exposure, vulnerability and restorability factors and was developed mainly by using multi-source data and the fuzzy comprehensive evaluation method. The results showed that high risk and middle risk areas account for 28% and 23% of the study area, respectively. They are distributed with an “S” type in the study area. Low risk and very low risk areas account for 21% and 10% of the study area, respectively. They are distributed in the west-central and southwestern parts. Very high risk areas account for 18% of the study area and are distributed in the northeastern parts. The results can be used to know the desertification disaster risk level. It has important theoretical and practical significance to prevention and control of desertification in Horqin Sand Land and even in Northern China.

Gestão ambiental: um estudo sobre a percepção do problema da desertificação no Estado do Rio Grande do Norte; Environmental management: a study on the environmental perception of the desertification of state of Rio Grande do Norte

Dantas, Carlos César Gadelha
Fonte: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Engenharia de Produção; Estratégia; Qualidade; Gestão Ambiental; Gestão da Produção e Operações Publicador: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Engenharia de Produção; Estratégia; Qualidade; Gestão Ambiental; Gestão da Produção e Operações
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
37.82%
The objective of this study was to investigate the environmental perception of: People with common-sense knowledge on the desertification process in RN. People with scientific knowledge on the desertification process in RN. Focal points in the combat at desertification of the RN and public ministery representant with actions in interinstitutional articulations promoter (and/or relative actions) at the desertification process in the RN. The research was carried in the city of Natal-RN and in two small cities of the Seridó region (RN): Caicó and Currais Novos. The research carried, is classified as exploratory and 22 people were interviewed. The research includes: The propension/intensity of the desertification in the RN and in the Seridó region; Evaluation of the knowledge of those interviewed, concerning the subject desertification ; Problems in order to combat desertification; Causes of desertification; The profile of the interviewed. The results of this present study indicate that the a desertification process is more agressive in the Seridó region than in the state of RN, being the two following: the absence of preocupation of the affected population with the process and the escarcity of governamental recurses, indicates how problems greather in the combat to the phenomen. Decreasing of produtivity in the agriculture and increasing of the migration to the urbans centers have been the main consequences of the process...

Participação pública em programas ambientais :um estudo em área suscetível à desertificação no Estado do Rio Grande do Norte; Public participation in environmetal programs: a study in a susceptible of desertification area in the state of Rio Grande do Norte

Vianna, Francisco Magno de Albuquerque
Fonte: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Engenharia de Produção; Estratégia; Qualidade; Gestão Ambiental; Gestão da Produção e Operações Publicador: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Engenharia de Produção; Estratégia; Qualidade; Gestão Ambiental; Gestão da Produção e Operações
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
37.21%
The natural resources degradation and its consequences to the society life have provided several discussions about the evaluation methods and environmental management, and the available means to minimize the effects of man s actions over the environment. Amongst these actions is the encouragement to the community participation in the process of carrying out the environmental programs, considering government and enterprises representatives or residents of certain places as social actors. Within these context, this paper had as a goal the investigation of the public participation in the environmental programs in areas that are susceptible to desertification, specificly in Parelhas/RN. The choice for this town was due to its insertion in an area considered as a desetification nucleous, which is, a region that suffers land degradation as a consequence of climate variations or human activities. Therefore, the research in question, of a descriptive and exploratory type, had as an instrument a structured questionnaire, applied to a sample of 223 people out of an 11,068 over 20 years of age residents population. The data have been tabled from Statistics for Windows Program and later interpreted based on the theoretical reference over the subject. As a result...

Applications of Remote Sensing and Geographic Information System techniques for desertification and land degradation monitoring and assessment in the Tillabéry landscape (Niger); Methoden der Fernerkundung sowie der Geoinformatik in Kombination mit Landschaftsstrukturanalysen und einer Bodenprobennahme in der Tillabéry Region (Niger)

Mansour, Mahamane
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
EN
Relevância na Pesquisa
37.73%
The Sahel region had a moderately good vegetation cover but presently, the land-scape is experiencing serious degradation. Research carried out in the field of desertification has not contributed to reducing or reversing these impacts. The spatio-temporal dynamics and intensities of desertification over 34 years were investigated. As such, the objective of this thesis is to investigate and monitor land degradation and desertification processes by using Remote Sensing, Geoinformatics and Geographic Information System techniques, in combination with landscape metrics and soil erosion models in the Tillabéry landscape. The evaluations of land use / land cover were carried out by classifying from one Landsat Multispectral Scanner (1973-09-30), one Landsat Enhanced Thematic Mapper plus (2001-09-18) and two Landsat TM images (1989-09-29 and 2007-09-27). The results of these classifications revealed an increasing trend in desertification throughout the study period. This study also brings into perspective the usefulness of landscape structure analysis within the context of desertification process analysis. A set of indices were selected to investigate multitemporal change in the Tillabéry landscape. These indices revealed an increase in the percentage of bare areas and also a decrease in shrub areas. The results show further that the Tillabéry landscape has a large number of patches with smaller patch sizes...

Mediterranean Desertification and Land Degradation - Mapping Related Land Use Change Syndromes Based on Satellite Observations

HILL J.; STELLMES M.; UDELHOVEN Th.; ROEDER A.; SOMMER STEFAN
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Articles in Journals Formato: Online
ENG
Relevância na Pesquisa
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Abstract In past decades, the European Mediterranean has undergone widespread land use transformations. These are largely driven by changes of socio-economic frameworks, such as accession to the European Community, and had strong effects on the way the land is being used. Aiming at a systematic description of change processes on a global level, the syndrome concept was proposed to describe archetypical, co-evolutionary patterns of civilization-nature interactions (Schellnhuber et al. 1997), and has been specifically linked to the desertification issue by Downing and LUdeke (2002). In this study, we present an adaptation of the syndrome approach to the Iberian Peninsula. We suggest a data processing and interpretation framework to map the spatial extension of specific syndromes for areas occupied by natural and semi-natural vegetation. The mapping approach is based on the time series analysis of satellite data. We have characterized vegetation dynamics using NDVI estimates from the coarse scale, hypertemporal 1km MEDOKADS archive, which is based on calibrated NOAA-AVHRR images. Results indicate that local patches of abrupt disturbance, mainly by fire, are contrasted by a widespread increase in biomass, which is in large parts attributed to the abandonment of rural areas. Although this questions the dominance of classical desertification traits...

Application of Indicator Systems for Monitoring and Assessment of Desertification from National to Global Scales

SOMMER Stefan; ZUCCA Claudio; GRAINGER Alan; CHERLET Michael; ZOUGMORE Robert; SOKONA Youba; HILL Joachim; DELLA PERUTA Raniero; ROEHRIG Julia; WANG Guosheng
Fonte: JOHN WILEY & SONS LTD Publicador: JOHN WILEY & SONS LTD
Tipo: Articles in Journals Formato: Printed
ENG
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Current initiatives of the UNCCD on defining minimum sets of indicators for monitoring and impact assessment of the implementation of the Convention have acknowledged that an important missing element in this process is an approved methodology of defining affected areas, emphasizing the importance of a more uniform identification methodology. Rather than discussing fixed indicator sets, this paper suggests how the UNCCD community progressively can make use of a flexible framework of analytical approaches that have been recently developed by scientific research, allowing a standardized but flexible use of indicator sets adapted to specific objectives or desertification issues relevant for implementing the Convention. Science has made progress in understanding major issues and proximate causes of dryland degradation such that indicator sets can be accordingly selected from the wealth of existing and documented indicator systems. The selection and combination should be guided according to transparent criteria given by existing indicator frameworks adapted to desertification conceptual frameworks such as the Dryland Development Paradigm (DDP). The concept of desertification issues suggested by recent research could be a pragmatic entry level for selecting area- and theme-specific sets of indicators from existing databases. Working on different dryland sub-types through a meaningful stratification is proposed to delimit and characterize affected areas beyond national levels. Such stratification could be achieved by combining existing Land Use information with additional biophysical and socio-economic data sets. This would allow indicator based monitoring and assessment in a framework of specific dryland degradation issues and their impact on key ecosystem services.; JRC.DDG.H.7-Land management and natural hazards

Monitoring and assessment of land degradation and desertification: Towards new conceptual and integrated approaches

VOGT Juergen; SAFRIEL Uriel; VON MALTITZ Graham; SOKONA Youba; ZOUGMORE Robert; BASTIN Gary; HILL Joachim
Fonte: JOHN WILEY & SONS LTD Publicador: JOHN WILEY & SONS LTD
Tipo: Articles in Journals Formato: Printed
ENG
Relevância na Pesquisa
27.5%
The implementation of the UNCCD needs agreed, scientifically sound and practical methodologies for monitoring and assessing the state and trend of land degradation as well as for monitoring the performance of management programs. The lack of sufficient and integrated monitoring and assessment (M&A) has in the past been identified as a major constraint for combating desertification. Implementing efficient M&A programs, however, requires careful analysis of the information needs of the different stakeholders, a clear scientific concept of the processes and drivers of land degradation and an analysis of the theoretical and practical possibilities for adequate M&A. This paper briefly analyses the information needs of diverse stakeholders, reviews existing M&A systems, and highlights key aspects for a scientifically sound approach to monitoring and assessment. Analysis of these approaches shows that in spite of their relevance, standardised procedures for their implementation at operational scales are lacking. This is partly attributable to the lack of agreed and clear definitions, related difficulties in defining and hence in measuring the attributes chosen to represent land degradation and desertification and the varying degrees of paucity of field data. There is also the urgent need to better integrate bio-physical and socio-economic aspects of desertification through a suitably robust scientific framework that links the drivers...

Estudo da desertificação no Alentejo: causas, consequências e estratégias atenuadoras (caso do Concelho de Arraiolos)

Toureiro, António José Pequito
Fonte: Universidade de Évora Publicador: Universidade de Évora
Tipo: Dissertação de Mestrado
POR
Relevância na Pesquisa
27.5%
A desertificação assume cada vez maior importância, pela degradação do meio ambiente e pela redução das produções agrícolas, que para além do sustento da população, são o motor da indústria e do comércio. O clima e o Homem, são as causas do fenómeno de desertificação. Pelos seus efeitos, sente-se cada vez mais necessidade de perceber e atenuar este fenómeno, através do uso sustentável do solo. A desertificação ocorre em muitos pontos do planeta. Também entre nós, em Portugal, e especialmente no Alentejo. O concelho de Arraiolos, situado no Alentejo Central, não é exceção, e sofre, nos dias que correm de desertificação, como resultado do despovoamento, do abandono da terra (já desflorestada e erosionada), do uso incorreto do solo (que com a atuação dos fatores climáticos, se degrada e desertifica). ***/Abstract - The desertification assumes every time larger importance, because of the degradation of the environment, and because of the reduction of the agricultural productions, that are the human sustain and the motor of the industry and trade. Both climate and Man are the causes of the desertification phenomenon. Because of them it’s necessary to notice and to lessen this phenomenon more and more...

Desertificação e reversibilidade dos problemas de desertificação

Charrua, Helena Cristina Cochicho
Fonte: ISA/UL Publicador: ISA/UL
Tipo: Dissertação de Mestrado
Publicado em //2014 POR
Relevância na Pesquisa
27.73%
Mestrado em Arquitetura Paisagista - Instituto Superior de Agronomia; The desertification process is related to land degradation in arid, semi-arid and dry sub-humid areas resulting from climate change and human activities. The effects of desertification are notorious at local, regional, national and global scale. Land degradation can be caused by erosion, salinization, compaction and reduction of nutrients. As a consequence of land degradation there will be a disruption of biological cycles on which life depends, as well as social development problems. Nowadays it is completely necessary and urgent to combat desertification processes. It's much more effective to prevent the degradation of these lands than reverse this process. The use of ecological restoration techniques are most appropriate for arid ecosystems affected by desertification. Portugal is one of the most affected European countries by desertification, approximately 60% of the territory is susceptible to desertification and drought. Over the past 50 years the area susceptible to desertification has increased. The PANCD is being applied to tackle this problem. The Alqueva Dam construction, Alentejo, has introduced several changes and impacts on the environment that can lead to desertification on this region of Portugal

What Has Caused Desertification in China?

Feng, Qi; Ma, Hua; Jiang, Xuemei; Wang, Xin; Cao, Shixiong
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em 03/11/2015 EN
Relevância na Pesquisa
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Desertification is the result of complex interactions among various factors, including climate change and human activities. However, previous research generally focused on either meteorological factors associated with climate change or human factors associated with human activities, and lacked quantitative assessments of their interaction combined with long-term monitoring. Thus, the roles of climate change and human factors in desertification remain uncertain. To understand the factors that determine whether mitigation programs can contribute to desertification control and vegetation cover improvements in desertified areas of China, and the complex interactions that affect their success, we used a pooled regression model based on panel data to calculate the relative roles of climate change and human activities on the desertified area and on vegetation cover (using the normalized-difference vegetation index, NDVI, which decreases with increasing desertification) from 1983 to 2012. We found similar effect magnitudes for socioeconomic and environmental factors for NDVI but different results for desertification: socioeconomic factors were the dominant factor that affected desertification, accounting for 79.3% of the effects. Climate change accounted for 46.6 and 20.6% of the effects on NDVI and desertification...

Assessing potential desertification environmental impact in life cycle assessment. Part 2: agricultural case study in Spain and Argentina

Civit, Bárbara María; Arena, Alejandro Pablo; Nuñez, Monserrat; Muñoz, Pere; Antón, Assumpció; Rieradevall, Joan
Fonte: Springer Heidelberg Publicador: Springer Heidelberg
Tipo: info:eu-repo/semantics/article; info:ar-repo/semantics/artículo; info:eu-repo/semantics/publishedVersion Formato: application/pdf
ENG
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Purpose Land use in dry lands can result in a final stage where land is completely depleted or entirely degraded causing the desertification phenomenon. The first part (part 1) of this series of two articles proposed a methodology to include desertification in life cycle assessment (LCA). A set of variables to be measured in the life cycle inventory, characterization factors, and an impact assessment method for the life cycle impact assessment phase were proposed. This second part (part 2) aims at showing the application of the model proposed in part 1 on two case studies of agricultural activities. Methods The impact model proposed is applied to plots of land devoted to agricultural activities in two countries: Argentina and Spain. In the agricultural plots of Spain (1SP to 9SP), two crops were analyzed: winter wheat (Triticum aestivum) and rapeseed (RS, Brassica napus). Two crops were considered in the Argentinean case study: rapeseed (RS, B. napus) and digit grass (Digitaria eriantha) (10AR to 17AR). A bare soil state is considered in both countries as a reference state. Both case studies consider only the agricultural stage in the inventory of a complete life cycle assessment study. Both also consider only one impact category in life cycle environmental assessment: desertification impact due to land occupation. Results and discussion On the basis of the obtained results...

Stochastic Desertification

Weissmann, Haim; Shnerb, Nadav M.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 31/12/2013
Relevância na Pesquisa
27.38%
The process of desertification is usually modeled as a first order transition, where a change of an external parameter (e.g. precipitation) leads to a catastrophic bifurcation followed by an ecological regime shift. However, vegetation elements like shrubs and trees undergo a stochastic birth-death process with an absorbing state; such a process supports a second order continuous transition with no hysteresis. We present a numerical study of a minimal model that supports bistability and catastrophic shift on spatial domain with demographic noise and an absorbing state. When the external parameter varies adiabatically the transition is continuous and the front velocity renormalizes to zero at the extinction transition. Below the transition one may identify three modes of desertification: accumulation of local catastrophes, desert invasion and global collapse. A catastrophic regime shift occurs as a dynamical hysteresis, when the pace of environmental variations is too fast. We present some empirical evidence, suggesting that the mid-holocene desertification of the Sahara was, indeed, continuous.

A QUESTÃO CLIMÁTICA DO NORDESTE BRASILEIRO E OS PROCESSOS DE DESERTIFICAÇÃO; THE CLIMATIC ISSUE OF THE BRAZILIAN NORTHEAST AND THE DESERTIFICATION PROCESSES

Bueno Conti, José
Fonte: UFPR Publicador: UFPR
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Formato: application/pdf; application/pdf
Publicado em 18/05/2011 POR
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37.38%
O presente trabalho discute os processos de desertificação na região Nordestedo Brasil, nas áreas de clima Semi-árido, a partir da utilização do métododas séries temporais. O quadro geral da análise indicou 49,7% das sériesapresentando tendência crescente nas médias pluviométricas, configurandouma distribuição geográfica indiferenciada, apresentando, contudo,incidência maior no Rio Grande do Norte, Paraíba e Pernambuco, sobretudono espaço compreendido entre o reverso continental da Borborema e chapadado Apodi e seus prolongamentos meridionais. Tal constatação indicaque a precipitação em nível regional acompanha a tendência de elevação damédia pluviométrica que vem sendo registrada nas últimas décadas, presumivelmenteassociada ao agravamento do efeito de estufa. Por outro lado,50,3% revelaram tendência estável ou decrescente, as primeiras, com distribuiçãogeográfica mal caracterizada, ao passo que as segundas agruparam-se em quatro manchas, sinalizadoras de indícios de desertificação localizada.; This article discusses desertification processes in the semi arid climates atNortheast Brazilian Region...

Dryland Management and Combating Desertification Through Development

Sardinha,Raul Manuel Albuquerque
Fonte: Unidade de Silvicultura e Produtos Florestais Publicador: Unidade de Silvicultura e Produtos Florestais
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2008 EN
Relevância na Pesquisa
27.69%
Although desertification process is not new or site specific, the environmental awareness in a world board scale has enlarged and generated a wider public interest, extensive to the scientific circles and governments. Desertification takes place in all continents except Antarctic and affects the livelihoods of millions of people, including a large proportion of the poor in drylands which occupies about 41% of the Earth's land and are home to more than 2 billion people. The persistence of unresolved stabilization of these fragile lands and the substantial reduction in the provision of ecosystem services as a result of intensive use of resources, incapacity of wide spread adequate technologies for providing increased supply of food, forage and fuel, water scarcity, and climate change puts desertification in among the greatest environmental challenges today and a major impediment to meeting human needs and attainment of the Millennium Development Goals. Scenarios for Climate change add up to environmental degradation associated with desertification bringing new threats of intensification of trends in the expansion of these degraded areas. In Portugal, the predictive scenarios on Climate Change points out the risk line of desertification overtaking already the Tagus River. Although Portugal is far better positioned than other desertification prone dry countries in the tropics and whose intervention examples are revised...