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Dissertations / Theses on the topic 'Desertification'
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Могильна, Наталія Олексіївна, Наталия Алексеевна Могильная, Nataliia Oleksiivna Mohylna, and Stanley Chizoba Mbelu. "Desertification in Africa." Thesis, Видавництво СумДУ, 2011. http://essuir.sumdu.edu.ua/handle/123456789/10075.
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Tshikesho, Desiderius Raimund. "A study of perceptions, knowledge and understanding of desertification and its causes among decision makers in northern Namibia." Thesis, Rhodes University, 1996. http://hdl.handle.net/10962/d1003664.
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This study was aimed at investigating the perceptions, knowledge and understanding of desertification and its causes among decision makers in northern Namibia. The focus of investigation was on desertification and its major causes as identified in the general literature, viz. deforestation, overgrazing and overcultivation. Particular attention was given to the socioeconomic and cultural factors which are behind these perceived 'ecological' causes of desertification. Furthermore, the respondents were also engaged in the generation of solutions to the problem of desertification and its causes. Data collection was based on semi-structured interviews with the regional governors, councillors and chief headmen from the four northern regions. A qualitative approach was adopted for the research and findings are essentially descriptive and qualitative. It is anticipated that the study will make an important contribution to the current debate on desertification in Namibia, specifically with regard to the perceptions, knowledge and understanding of desertification and its causes among the decision makers in northern Namibia.
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Milich, Lenard B. "Characterizing and relating variability in satellite images of the West African Sudano-Sahel to desertification and food security." Diss., The University of Arizona, 1997. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1997_216_sip1_w.pdf&type=application/pdf.
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Smith, Richard D. "Desertification, overgrazing and soil spatial variability in an arid savanna." Thesis, University of Sheffield, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327643.
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Owusu, Alex B. "Detecting and quantifying the extent of desertification and its impact in the semi-arid Sub-Saharan Africa a case study of the Upper East Region, Ghana /." Fairfax, VA : George Mason University, 2009. http://hdl.handle.net/1920/4576.
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Thesis (Ph.D.)--George Mason University, 2009.Vita: p. 287. Thesis co-directors: Sheryl L. Beach, Guido Cervone. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Earth Systems and Geoinformation Sciences. Title from PDF t.p. (viewed Oct. 11, 2009). Includes bibliographical references (p. 267-286). Also issued in print.
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Hamza, Kanar. "Desertification and political instability in the Tigris and Euphrates river basins /." Full-text of dissertation on the Internet (2.54 MB), 2010. http://www.lib.jmu.edu/general/etd/2010/masters/hamzakh/hamzakh_masters_05-06-2010.pdf.
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Lopes, da Fonseca Ines de Figueiredo Mascarenhas. "Modelling soil properties at the landscape scale in a desertification context." Thesis, King's College London (University of London), 2005. https://kclpure.kcl.ac.uk/portal/en/theses/modelling-soil-properties-at-the-landscape-scale-in-a-desertification-context(ffb67ea2-a86e-4045-bf53-a708b2c5c997).html.
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Long, Marybeth 1967. "Grains of truth : science and the evolution of international desertification policymaking." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/9140.
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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2000.Includes bibliographical references (leaves 321-346).
This study explores changing perceptions of dryland degradation (desertification) as revealed through twentieth century intergovernmental policies. Between the 1930s and 1990s these policies reflected markedly different ideas regarding the nature of the problem (e.g., global or local), its causes (e.g., natural or anthropogenic), and its remedies (e.g., based on modem science or indigenous knowledge). In the 1970s, for example, policies portrayed desertification as a phenomenon of worldwide extent. They identified "irrational systems of productivity" as primarily responsible for the problem and prescribed technological means for its amelioration. In the 1990s policies emphasized the local variability of land degradation. They attributed desertification to complex interactions involving ecological, political and economic factors, and called for decentralized programs and public participation. This thesis argues that the history of desertification as a policy issue does not conform to traditional notions of progress whereby advances in science enable and underwrite advances toward effective governance. In this case, varied framings of the problem, rather than emerging from improved understandings of nature, arose from interactions linking the creation of scientific knowledge with the formation of international environmental institutions. The study identifies four discrete periods of international desertification politics: colonial, modernist, internationalist and pluralist, and undertakes a comparison of expert advisory processes, quantification, and visual representations across the periods. On the basis of this comparison the thesis presents an alternative interpretation of policy change and identifies three processes by which science and international governance were mutually constitutive and evolved in tandem: authorization, inscription, and boundary work. Authorization is the process that determines whose knowledge counts and what methods of knowledge production are valid. Inscription describes the means by which institutional resources and priorities embed problem framings and causal narratives. Boundary work concerns efforts to organize activities, delegate responsibility, and determine rules of participation. In the desertification case, boundary work proved important in delineating realms of science and non-science, lay-expert, natural-social, and local-global. Recognition of these processes opens the way to redefining expertise and redesigning expert advisory processes in current international environmental regimes.
by Marybeth Long.
Ph.D.
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Benkhalti, Abdellah. "Mapping the Desertification Process in Southern Morocco Using Remote Sensing Data." TopSCHOLAR®, 1987. https://digitalcommons.wku.edu/theses/2149.
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Desertification is a problem occurring in arid and semiarid zones all over the world. It is a consequence of mismanagement of the land. Human activities and livestock pressure on such fragile ecosystems lead to a deterioration of the soil by increasing its salinity, lessening its moisture, and covering it with sand and dust. Aerial photographs and satellite images constitute a tool for mapping and monitoring the desertification process. Multispectral data can assist in detecting the indicators of desertification in early stages in order to plan adequate action.
The improvement of the resolution of satellite images and the fact that they are available on a periodic basis make the use of these data suitable for mapping the evolution of desert patches at large scales. The green band of Landsat MSS is used in this study.
Two images taken, respectively, in 1976 and 1985 and covering the province of Ouarzazate in southern Morocco are used to map the desertification process and its evolution in the region. At the scale used and given the ground resolution of the MSS (80 meters), significant changes were found between the two images. However, changes occurring at scale smaller than 80 meter square were impossible to detect by visual interpretation of this band.
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Abbasova, Tahira. "Detection and analysis of changes in desertification in the Caspian Sea Region." Thesis, Stockholms universitet, Institutionen för naturgeografi och kvartärgeologi (INK), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-43241.
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The Caspian Region includes the Caspian Sea and five littoral states: Azerbaijan, Iran, Turkmenistan, Kazakhstan and Russian. 40% of the Caspian coastal zone is arid, 69% of this territory undergone desertification according to international reports. Among the reasons are soil erosion caused by water, wind and irrigation, the salinization of soil, intense bioresources usage, and soil pollution due to oil extraction and production. Desertification is a serious problem, at global, national and local scales. It is important to know what should be sustained or developed in order to protect land from desertification. The generalization of data over desertification processes in Caspian countries, studying the dynamics of this process in space and time could help facilitate measures to counter regional desertification. To understand Caspian Region coastal desertification phenomenon, vegetation cover satellite images for the years 1982 – 2006 were investigated to give map vegetation changes over time. The Normalized Difference Vegetation Index (NDVI) data for this study was derived from the Global Inventory Modeling and Mapping Studies (GIMMS) dataset, with the spatial resolution of 8 km. A coastal strip 160 km from the coast, divided by countries, was investigated. Theanalyses were focused on extent and severity of vegetation cover degradation, and possible causes such as landscape, land use history and culture, climatic changes and policies. The aim was to address questions related to desertification phenomenon, by focusing on Caspian Region time-series of vegetation cover data and investigation patterns of desertification in the region. In this study evidence of land degradation in the Caspian Region countries was found to occur on local scales or sub-national scales rather than across the regional as a whole. Changes in vegetation cover revealed by AVHRR NDVI appeared to be reversible in character and were dependent on the climate conditions, and anthropogenic impact in approximately equal proportions.
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Bradley, Daniel. "A reassessment of desertification processes : the role of social resilience in Senegal." Thesis, University of Leeds, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272618.
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Hutchison, Leah (Leah Ellen Ann). "Determining land use change and desertification in China using remote sensing data." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/114113.
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Thesis: S.B. in Geosciences, Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2004.Cataloged from PDF version of thesis. Some pages in original thesis contain text that run off the edge of the page.
Includes bibliographical references (pages 61-64).
Desertification, the spread of desert-like conditions in arid or semiarid areas due to human influence or to climatic change, affects most arable land in arid and semi-arid China. This project provides an analysis of desertification in northeastern arid and semi-arid China to determine its spatial distribution, severity, and causes. It locates areas of desertification and identifies and ranks in order of importance their anthropogenic and climatological causes. It especially focuses on the savanna transition zone west of Beijing to see if climate factors or increasing population density can be correlated to land cover change. GIS (Geographic Information Systems) software is used to recognize locations of rapid land cover change. Statistical tests, such as unbalanced multi-way ANOVA, determine if climatic or anthropogenic factors can predict if an area is undergoing rapid land cover change. The climate and population data is resampled to an uniform 0.5' scale and converted into qualitative, data before statistical testing. This project tests if land cover change, a more difficult indicator to measure, can be predicted by analyzing trends in vegetation, precipitation, temperature, wind and population. Desertification is more likely and more severe in climates with low precipitation. Areas with low population density tend to have less severe land degradation than areas with medium or high density; this may be due to more intense land use in high population areas.
by Leah Hutchison.
S.B. in Geosciences
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Ferreira, Mirele Paula da Silva. "Changes of attributes of soil submitted to the fallow on core desertification." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=16467.
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FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgicoSoil degradation can occur because of inadequate management, which may result in soil unproductive and, in certain situations, lead to the desertification process. One of the causes of degradation is overgrazing, causing loss of biodiversity of plant strata by the pressure of ramoneio and soil compaction by excessive trampling of animals, bringing implications to the ground in the physical, chemical and biological properties, thereby undermining the sustainability of the agroecosystem. An alternative to recover soil degradation is the practice of fallow, because that is easy to perform and inexpensive to restore soil properties that provides input of organic matter, important soil conditioner. With that aimed to prove the hypothesis that the time of 14 year fallow improves the physical and chemical soil in degraded areas in the process of desertification. The areas selected for the study are located in the municipality of IrauÃuba in the state of CearÃ, Brazil. Soil samples were taken in five areas of overgrazing, in five areas of fallow and in a forest area, is serving as the reference area. Physical and chemical analysis of the soil as soil density, total porosity, flocculation, pH, electrical conductivity, cation exchange capacity (CTC), total organic carbon, carbon management index and physical fractions of organic carbon, were done to assess the changes the physical and chemical attributes of these areas. The management of fallow showed improvements in physical and chemical soil when assessed after 14 years of withdrawal of animals, but when compared to the work done in the same area in 2009, with 7 years of fallow, evidence that the areas are still in the process of degradation. The organic carbon content was higher in the areas of fallow and the fraction with the highest proportion was the organic carbon associated to minerals.
A degradaÃÃo do solo pode ocorrer em funÃÃo do manejo inadequado, o qual pode acarretar na improdutividade do solo e, em certas situaÃÃes, levar ao processo de desertificaÃÃo. Uma das causas da degradaÃÃo à o sobrepastejo, ocasionando perda da biodiversidade do estrato vegetal pela pressÃo do ramoneio e compactaÃÃo do solo pelo pisoteio excessivo dos animais, trazendo implicaÃÃes ao solo nas propriedades fÃsicas, quÃmicas e biolÃgicas, comprometendo assim a sustentabilidade do agrossistema. Uma alternativa para recuperar a degradaÃÃo do solo à a prÃtica do pousio, pois essa à de fÃcil execuÃÃo e de baixo custo para restaurar as propriedades do solo que proporciona aporte de matÃria orgÃnica, importante condicionador do solo. Com isso, objetivou-se comprovar a hipÃtese que o tempo de pousio de 14 anos melhora os atributos fÃsicos e quÃmicos do solo em Ãreas degradadas em processo de desertificaÃÃo. As Ãreas selecionadas para o estudo estÃo localizadas no municÃpio de IrauÃuba, no Estado do CearÃ, Brasil. Foram realizadas coletas de solo em cinco Ãreas de sobrepastejo, em cinco Ãreas de pousio e em uma Ãrea de mata, esta servindo como Ãrea de referÃncia. AnÃlises fÃsicas e quÃmicas do solo como: densidade do solo, porosidade total, grau de floculaÃÃo, pH, condutividade elÃtrica, capacidade de troca de cÃtions (CTC), carbono orgÃnico total, Ãndice de manejo de carbono e fracionamento fÃsico do carbono orgÃnico, foram feitas a fim de avaliar as modificaÃÃes nos atributos fÃsicos e quÃmicos destas Ãreas. O manejo de pousio apresentou melhorias em atributos fÃsicos e quÃmicos do solo quando avaliado apÃs 14 anos de retirada dos animais, mas quando comparada ao trabalho realizado na mesma Ãrea em 2009, com 7 anos de pousio, evidÃncia que as Ãreas ainda estÃo em processo de degradaÃÃo. O teor de carbono orgÃnico foi maior nas Ãreas de pousio e a fraÃÃo com maior proporÃÃo foi o carbono orgÃnico associado aos minerais.
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Bell, Wesley. "Mapping desertification: towards an approach for mapping regional land degradation in drylands." Doctoral thesis, Faculty of Science, 2020. http://hdl.handle.net/11427/32201.
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Land degradation in drylands (desertification) is an issue that potentially impacts nearly half of the world's human population living on over a third of the Earth's land surface. Despite global concern of the impact of desertification on people and the environment, there is no universal method to assess and map desertification. Methods to assess desertification at the local to regional scale that can fit into a broader global desertification narrative are more appropriate. The overall objective of this thesis is to assess regional desertification using field and Earth observation data for the Namaqualand Hardeveld bioregion of South Africa. Field data on the condition of the land from 277 plots was analysed using Latent Class Analysis (LCA) and found to cluster into three separate states. The first state (S1) was comprised primarily of degraded plots. The third state (S3), on the other hand, was comprised primarily of non-degraded plots, while the plots in state two (S2) generally fell between those which were assigned to S1 and S3. Through the LCA, each plot was assigned a probability of belonging to each state, and the most important variables in distinguishing the three states (perennial plant cover and bare ground cover) were identified. A total of 16 remote sensing variables were determined for the project area. Five vegetation indices (NDVI, EVI, SAVI, OSAVI, MSAVI), as well as spectral mixture analysis (SMA) cover estimates for perennial vegetation, bare ground and bare rock were calculated using both Landsat 8 and Sentinel-2A data. These variables were used in a series of Partial Least Squares regression (PLSr) models to predict either the probability of a plot belonging to one of the three latent states, or the field estimated perennial plant and bare ground cover. The best performing PLSr model had ten remote sensing variables predicting the field estimates of cover (R2Ycum = 0.592; Q2cum = 0.554). Both Sentinel-2A and Landsat 8 SMA cover estimates were better at predicting field cover than any of the vegetation indices. Estimates of bare ground and perennial plant cover were projected over the project area using the PLSr model and ground truthed using data from 61 independent field test plots. There was a significant correlation between the PLSr estimates and the field estimates for both perennial plant cover and bare ground cover for the test plots with the best correlation found to be between the PLSr estimate of bare ground and field estimated bare ground cover (r = 0.827, p < 0.001, CI [0.727, 0.893]). The trendline slope and percentile range of a time series of the Landsat SMA bare ground estimate were used to create raster images. These images, along with images for the PLSr bare ground and perennial plant cover estimates, were converted into images representing membership values between zero and one for the habitat condition archetype. These three images were then combined to produce one raster representing the overall membership of the project area to the habitat condition archetype. The importance of five potential drivers of land degradation (elevation, slope aspect, slope steepness, rainfall trend, and land tenure) in predicting PLSrestimated perennial plant and bare ground cover were evaluated using a random forest model. All drivers were found to be important predictors of cover and were included in the construction of the final, multi-band archetype image. If habitat condition classes are designated according to the mean archetype membership value ± one / two standard deviations, then 17% of the project area could be considered moderately degraded, with just over 3% severely degraded. This novel method of assessing and mapping desertification leads to improved accuracy in predicting habitat condition in the context of potential drivers of change. The utility of SMA over traditional vegetation indices is supported for this particular environment. This methodology can be improved with better endmember designation as well as improved spatial data on the potential drivers of change in drylands. The archetype approach ensures less subjectivity in map production, and the retention of pertinent information in map products. The approach developed in this thesis will allow for more accurate desertification reporting for UNCCD member states and will ultimately improve efforts to combat desertification globally.
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Nunes, Alice Maria Rodrigues. "Plant functional response to desertification and land degradation: contribution to restoration strategies." Doctoral thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/18814.
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Doutoramento em Biologia e Ecologia das Alterações GlobaisÉ crucial entender o impacto das alterações climáticas nos ecossistemas áridos, pois estas poderão agravar a desertificação e degradação dos solos, comprometendo o funcionamento dos ecossistemas e os serviços a eles associados. Os atributos funcionais ligam as espécies aos processos do ecossistema, fornecendo um entendimento mecanicista da sua resposta ao clima. O principal objectivo desta tese foi modelar a resposta de ecossistemas áridos ao clima com base em atributos funcionais de plantas (AFP), usando um gradiente climático espacial para prever alterações no tempo. Pretendeu-se assim selecionar um indicador baseado em AFP para monitorizar os efeitos do clima, e contribuir para melhorar as estratégias de gestão e restauro de zonas áridas. Embora a maioria das métricas de diversidade funcional requeiram a quantificação dos AFP no campo, não existia consenso sobre qual o melhor método para ser usado à escala global. Comparámos diferentes métodos, e demonstrámos as vantagens do método dos quadrados pontuais na monitorização de fina-escala dos AFP em zonas áridas. Desconhecia-se quais os principais AFP que respondiam à aridez, o que é essencial para o seu uso como indicadores de alterações no ecossistema. Identificámos nove AFP que respondem à aridez. Esta afectou a respectiva média, e reduziu a diversidade funcional. O uso de gradientes climáticos no espaço para prever alterações no tempo, requer a comparação de ambos os padrões, para a respectiva validação. Verificámos que as variações climáticas entre anos afectam os AFP, indicando que as mudanças funcionais são transitórias. Contudo, a diversidade funcional diminuiu em condições climáticas mais limitantes. Assim, face a uma maior aridez, espera-se que os padrões de resposta no tempo convirjam para os verificados no espaço. Os AFP podem responder de forma mais previsível ao clima do que a diversidade de espécies. Desenvolvemos um indicador de diversidade funcional baseado em múltiplos AFP, que diminuiu de forma monotónica não-linear com a aridez, mostrando ter maior capacidade preditora da resposta ao clima do que a diversidade de espécies. Os factores biofísicos locais modulam o efeito do clima na vegetação. Verificámos que os factores topo-edáficos têm um papel chave nos AFP envolvidos na colonização por arbustos. Os factores climáticos pouco influíram, sugerindo que as alterações climáticas não promoverão a colonização por arbustos. Os AFP podem ser uma ferramenta essencial no restauro de zonas áridas. Apresentámos uma visão geral sobre projectos de restauro, mostrando a necessidade de uma melhor integração dos AFP no restauro de zonas áridas. Ao demonstrar que os AFP são indicadores consistentes do impacto do clima nos ecossistemas, contribuímos para melhorar as previsões dos efeitos das alterações climáticas nas zonas áridas, e desenvolvemos um indicador que pode ser usado para mapear áreas em risco de desertificação e degradação do solo, potencialmente a uma escala global.
It is crucial to anticipate the impacts of climate change on drylands, as it may aggravate desertification and land degradation, hampering ecosystems functioning and associated services. Functional traits determine species’ responses to environment, and their influence on ecosystem processes, thus providing a mechanistic tool to monitor ecosystems’ response to climate. The main aim of this thesis was to model the response of Mediterranean dryland ecosystems to climate, based on plant functional traits (PFT), using a spatial climatic gradient to predict changes over time. It aimed at selecting a traitbased indicator to track climate change effects on drylands, and contribute to improve land management and restoration strategies to mitigate land degradation. Although most trait-based metrics require the quantification of PFT in the field, there is no consensus about the best plant-sampling method to do it, to be used at a global scale. By comparing the performance of different methods, we demonstrated the advantages of the point-intercept method to perform fine-scale monitoring of PFT in drylands. Understanding which PFT respond to climate is essential to their use as indicators of ecosystems´ changes. Yet, this is not well established in drylands. We identified nine PFT responding to aridity. It affected PFT means, and reduced functional diversity. Studying climatic gradients in space to infer changes over time, requires a validation between the two. We found that inter-annual climatic fluctuations greatly affected PFT, indicating that functional changes are transitory. Yet, functional diversity was reduced under more limiting climatic conditions. Hence, we hypothesize that if drier conditions prevail in time, changes over time will approach those found along space. PFT are likely to respond in a more predictable way to environment than species diversity. We built a multi-trait functional diversity indicator, which showed a monotonic non-linear decrease with increasing aridity, responding in a more predictable way to climate than species diversity. Local biophysical factors modulate the effect of climate on plant communities. We explored the relative effect of these factors, and found that topo-edaphic factors played a major role shaping PFT associated to shrub encroachment. Climatic factors had a minor influence, suggesting that climate change will not promote shrub encroachment in Mediterranean drylands. PFT may be an important tool to improve dryland restoration. We provide a comprehensive overview of the current restoration practice in Mediterranean drylands, showing the need for a better integration of trait-based ecology into dryland restoration. By showing that PFT are consistent indicators of the impact of climate on dryland ecosystems, this work contributed to improve predictions on the effects of climate change on drylands, and enabled the development of a trait-based indicator which can be used to map areas at risk of desertification and land degradation, potentially at a global scale.
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Mnsur, Shaban Emhamed Abdsmad. "An evaluation of land degradation and desertification in the Jeffara Plain, Libya." Thesis, Sheffield Hallam University, 2014. http://shura.shu.ac.uk/20069/.
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The research develops the Mediterranean Desertification and Land Use methods and makes then more appropriate for studying land degradation in arid and semi-arid zones. In this research, three approaches were applied to land degradation assessment in the central southern part of the Jeffara Plain in Libya: remote sensing, Mediterranean Desertification and Land Use (MEDALUS) and Universal Soil Loss Equation (USLE).The Mediterranean Desertification and Land Use Method was used to determine the environmentally sensitive areas (ESAs) in the study area. In addition, this model has been developed by adding two parameters: groundwater management and wind speed. These were not directly applied in the original MEDALUS model and their incorporation makes the method more suitable to the arid and semi-arid zones. Landsat images were used for the years 1986, 1996 and 2002 and Spot images for the year 2009. The supervised classification (the enhanced maximum likelihood classification) algorithm was applied to generate land cover maps together with the matrix analysis. They were used to analyse and extract land information covering the changes in the study area; they detected and assessed the changes for the period from 1986 to 2009.In addition to processing the satellite MODIS images, the data were used to identify the relationship between the climate and the vegetation indices (NDVI) for the period from 2001 to 2009.The Universal Soil Loss Equation (USLE) was used with a Geographic Information System (GIS) to determine quantitatively the average annual soil loss in the study area. A GIS file was created for each factor of the USLE: precipitation, soil type, land cover, and slope, combined with the cell-grid modelling procedures in Arc GIS to predict the soil erosion risk. The results obtained from remote sensing demonstrated significant decrease in natural vegetation and significant degradation in most of the land in the study area. About 85% of the study area was 'moderate' or 'severe' in terms of degradation, as defined land cover maps and land degradation maps were produced for the study area. Findings from the Mediterranean Desertification and Land Use method showed that almost 75% of the total study area was sensitive to 'critical' desertification. A map for the environmentally sensitive areas vulnerable to desertification was produced for the study area. In contrast, the results obtained from USLE revealed 'slight' erosion rates in the rangelands and the agricultural lands which together account for 76% of the total land area. A soil erosion map was also produced for the study area.
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Vit, Margaux <1992>. "Desertification and environmental refugees: concrete problems in the context of climate change." Master's Degree Thesis, Università Ca' Foscari Venezia, 2018. http://hdl.handle.net/10579/12162.
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Climate change has been subject of great debate in recent years. Despite differing opinions, climate change is happening now and it is a real and serious issue. The effects of climate change, which are attributed to human activity through greenhouse gases emissions, are tangible and proven; they affect different elements of our planet, such as the atmosphere and the cryosphere, oceans and sea level. Because of climate change impacts on the environment, it influences the drivers of migration, even if it is not a direct driver. In this context, desertification is a process of environmental degradation derived also from climate change. Nowadays, it is one of the most serious environmental emergencies due to dryness, drought and erosion caused by precipitations, together with anthropic factors. As a consequence, land productivity and ecosystem services are reduced, affecting food security, water supply and agricultural productivity, worsening the economic conditions of those depending on agriculture. In addition to that, desertification and climate change (more generically) cause migration, triggering a vicious cycle of cause-effect that is risky for humans. Those who migrate because of climate change affecting the drivers are named “environmental refugees”. There is a huge debate about the definition of this term, and an agreement has not been reached yet. Moreover, given that the Refugee Convention does not include climate change as a reason to receive refugee status, they are not juridically recognized as refugees. Also about that, there is an ongoing debate. Concluding, domestic and international policies are matter of discussion to reduce migration and/or to prepare developed countries to host migrants.
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Kone, Alassane. "Modelling and Decision Support for a Desertification Issue Using Cellular Automata Approach." Electronic Thesis or Diss., Guyane, 2023. http://www.theses.fr/2023YANE0001.
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La désertification, en tant que problématique majeure affectant la vie sur Terre, a d’énormes conséquences qui dégradent la qualité de vie des hommes, leurs activités quotidiennes et leurs moyens de subsistance. Pour lutter contre son avancée, les organisations internationales ont mis en place des actions pour ralentir ou arrêter son expansion et réduire ses impacts.Cette thèse s’inscrit dans la lutte contre la désertification en modélisant le processus de dégradation des terres conduisant à la désertification. Deux modèles sont développés : le premier combine des automates cellulaires continus et l'évaluation MEDALUS, évaluant la désertification sur la base des indices des facteurs sol, végétation, climat et management. Le deuxième modèle simule la dégradation des terres en utilisant le couple automates cellulaires/Modèle MEDALUS, enrichi par des facteurs anthropiques comme les pratiques d'utilisation des terres, le facteur d'exploitabilité et l’appartenance foncière, formant le Modèle Amélioré de Désertification. Ce modèle sert de base au logiciel DESERTIfication Cellular Automata Software (DESERTICAS), permettant de simuler l'évolution spatio- temporelle de la dégradation des terres. DESERTICAS facilite l'exploration de scénarios de dégradation des terres dans le temps et l'espace.Ces modèles développés intègrent des processus dynamiques dans le modèle MEDALUS à la base statique et permettent d’étendre la notion d’état des automates cellulaires classiques à des états continus. L’identification d’un facteur prédominant permet d’agir sur tout le système conduisant à la désertification. Notre étude met en évidence le management, action humaine, comme facteur prédominant affectant indirectement les autres facteurs. Agir positivement sur le management permet d’interrompre les sources de dégradation, de ralentir ou arrêter la dégradation des terres. La théorie du contrôle est également appliquée au modèle d'automates cellulaires développés et permet d’agir sur le facteur prédominant à partir des algorithmes génétiques. En intégrant des actions de protection des terres dans les simulations liées à la désertification, le logiciel DESERTICAS devient un outil d'aide à la décisionDesertification, as a significant challenge impacting life on Earth, has extensive consequences that degrade human life quality, daily activities, and livelihoods. In response, international organizations have implemented actions to slow or stop its progress and reduce its impacts. This thesis focuses on combating desertification by modelling the process of land degradation leading to desertification. Two models are developed: the first combines continuous Cellular Automata and the MEDALUS assessment, evaluating desertification based on soil, vegetation, climate, and management. The second model simulates land degradation using cellular automata approach, enriched with anthropogenic factors like land use practices, exploitability factor and ownership, forming the Enhanced Model of Desertification. This model serves as the basis for DESERTIfication Cellular Automata Software (DESERTICAS), simulating spatio- temporal land degradation evolution. DESERTICAS facilitates scenario exploration by simulating land degradation progression over time and space. The models incorporate dynamic processes into the MEDALUS model, expanding classical Cellular Automata to continuous states. Identifying a predominant factor influencing desertification, management emerges as crucial, affecting other factors indirectly. Positive management actions can interrupt degradation sources, slowing or halting land degradation. The thesis also applies control theory to the Cellular Automata model, aiming to influence the predominant factor using Genetic Algorithms. By integrating land protection actions into desertification simulations, the DESERTICAS software becomes a decision support tool
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Narayanan, Anne Michelle. "Foraging distances and forager population sizes of the desert termite Gnathamitermes tubiformans (Buckley) (Isoptera: Termitidae)." Texas A&M University, 2004. http://hdl.handle.net/1969.1/2762.
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The desert termite Gnathamitermes tubiformans and its unique foraging tubes are a common fixture in rangelands across Arizona, New Mexico, northern Mexico, and Texas. Although it is a native species and has thrived for millions of years, recent droughts have made its activity more visible and raised questions about its impact on vegetation. Since G. tubiformans prefers grasses as food, there has been a concern about competition between livestock and termites. Monitoring of desert termite activity was conducted through two experiments focusing on foraging distances and forager population sizes.
The foraging distances experiment used circular grids in 5 m x 5 m plots to map the movement of marked G. tubiformans released from the center of the grid. Analyses showed no significant correlations between distances moved and abundance or type of vegetation. Movement of marked termites did not favor any compass directions.
The second experiment used a mark-recapture estimation model to predict G. tubiformans forager populations in 5 m x 5 m plots. Linear regression analyses showed a significant positive correlation between size of the forager population and amount of total vegetation. In addition, linear regression analyses showed a significant positive correlation between total estimated number of collected termites during early recruitment and amount of vegetation cover, specifically grasses.
Desertification of rangelands used by G. tubiformans and livestock is a worry with few known solutions. Elucidating answers to this problem involves ferreting out the sources of the degradation. The results of this thesis shed light on the role G. tubiformans plays in its habitat, and infer that degraded habitats with low amounts of vegetation will exhibit low termite populations.
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EL, GASMI BENALI. "Piemont du haut-atlas de midelt "maroc" : phenomene de desertification et perspectives d'amenagement." Toulouse 3, 1987. http://www.theses.fr/1987TOU30039.
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Ce travail porte sur la mise en evidence du phenomene de desertification dans la region du haut-atlas de midelt, maroc, a partir d'etudes de terrain et de la cartographie. On distingue 3 unites ecologiques: - versant calcaire couvert par 1 foret de chene vert; les activites humaines sont le paturage et l'exploitation des bois. - paysage de l'alfa: on y trouve des paturages, des cultures cerealieres et des extractions minieres. - terrasses et glacis du quaternaire recent avec culture intensive avec irrigation. On analyse l'action du climat et celle de l'homme sur la desertification puis on aborde la question de l'amenagement
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CRISTINA, GIULIO. "The hidden potential of digested sewage sludge: a recycling approach to combat desertification." Doctoral thesis, Politecnico di Torino, 2021. http://hdl.handle.net/11583/2903484.
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Corell, Elisabeth. "The negotiable desert : expert knowledge in the negotiations of the Convention to Combat Desertification /." Linköping : Tema, Univ, 1999. http://www.bibl.liu.se/liupubl/disp/disp99/arts191s.htm.
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Lingbeek, Brandon James. "Arthropod diversity response to deforestation and desertification in the Sahel region of western Senegal." Thesis, Tarleton State University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10149640.
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Biodiversity has decreased due to anthropogenic activities, and extinction rates are currently one hundred to one thousand times greater than the background rate. While the connection between deforestation and biodiversity loss is well documented within tropical rainforest ecosystems, comparatively little is known about the effects of desertification on biodiversity in dryland ecosystems. Drylands, which cover nearly half the terrestrial surface and are highly vulnerable to desertification, are among the most endangered ecosystems. To understand how biodiversity responds to environmental degradation in these fragile ecosystems, I studied arthropod diversity within a human-modified landscape suffering from deforestation and desertification in the Sahel of western Senegal. My specific objective was to determine whether arthropod, beetle, spider and ant diversity differed between protected areas of tropical dry forest and surrounding communal lands suffering from desertification. I established 12 quadrats spaced homogenously throughout each protected area as well as adjacent communal land at three different locations (Beersheba, Bandia and Ngazobil). Within each quadrat, I measured canopy closure, characterized vegetation and collected arthropods using pitfall traps during the 2014 dry (May) and rainy (September) seasons.
I collected 123,705 arthropods representing 733 morphospecies, 10,849 beetles representing 216 morphospecies, 4,969 spiders representing 91 morphospecies and 59,183 ants representing 45 morphospecies. Results showed protected areas contained greater arthropod and spider diversity than communal lands, beetle diversity varied depending on location and season, and communal lands contained greater ant diversity than protected areas (P ≤ 0.05). My results illustrate the importance of a multi-taxa approach in understanding biodiversity response to anthropogenic disturbances. Conserving arthropod diversity in the Sahel will require the creation and preservation of more protected areas of a variety of sizes and successional stages as well as the adoption and extension of land-restorative techniques such as Zai and farmer managed natural regeneration (FMNR).
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Pessoa, Carla Daniela de Sales. "Soil Seed Bank in a Caatinga area in Regeneration, Center for Desertification IrauÃuba, CearÃ." Universidade Federal do CearÃ, 2008. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=9200.
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CoordenaÃÃo de AperfeiÃoamento de NÃvel SuperiorO presente trabalho tem como objetivo conhecer os atributos do banco de sementes no solo e verificar quais desses refletem melhor a regeneraÃÃo da caatinga em Ãreas de desertificaÃÃo. Para tanto, investigou-se o banco de sementes no final da estaÃÃo seca, em uma Ãrea de caatinga em processo de degradaÃÃo/desertificaÃÃo, no municÃpio de IrauÃuba, CearÃ. Foram analisados os atributos densidade, composiÃÃo, diversidade e riqueza de espÃcies e cinÃtica de germinaÃÃo. As coletas foram realizadas em trÃs Ãreas, nas fazendas Formigueiro, Cacimba Salgada I e Cacimba Salgada II. Em cada Ãrea foi amostrado o banco de sementes no solo na parcela experimental (pousio) e na parcela em uso contÃnuo (controle). Cada parcela de cada Ãrea foi subdividida em dezesseis parcelas de 10x10m, das quais foram sorteadas cinco para estudo do banco de sementes no solo. No centro de cada uma das cinco parcelas de 100m2 foi retirada amostra de solo de 0,25m2 de Ãrea. A densidade e a composiÃÃo do banco de sementes no solo foram analisadas atravÃs da tÃcnica de emergÃncia de plÃntulas em casa de vegetaÃÃo. O banco foi composto prioritariamente por terÃfitos. As densidades encontradas foram 592, 1804, 2080 sem/m2 para as parcelas experimentais 1, 2 e 3, respectivamente e 680, 1288 e 1408 sem/m2, para as parcelas controle 1, 2 e 3, respectivamente. No parÃmetro riqueza, foram encontrados iguais valores para as parcelas experimento e controle (8 e 2 para as Ãreas 1 e 2, respectivamente), a Ãrea 3 apresentou maior riqueza na parcela em pousio (15 e 10 para as parcelas controle e experimento, respectivamente). Os valores de equabilidade nas parcelas experimento foram de 0,751, 0,041 e 0,740 para as Ãreas 1, 2 e 3, respectivamente, e de 0,613, 0,054 e 0,603 para as Ãreas 1, 2 e 3 das parcelas controle. Em relaÃÃo à diversidade, os valores para as parcelas experimentais 1, 2 e 3 foram 1,562, 0,028, 2,004, respectivamente, e 1274, 0,038 e 1,388 para as parcelas controle, 1, 2 e 3, respectivamente, o que revela uma maior diversidade nas Ãreas em pousio, com exceÃÃo da Ãrea 2. Os aumentos da diversidade e da densidade demonstram a ocorrÃncia de regeneraÃÃo do componente herbÃceo nas Ãreas em pousio.
The objective of this study is to gather knowledge about the attributes of a seed bank at soil level and to verify which of these attributes reflect the best regeneration of the caatinga in areas of desertification. In order to do that, we investigated the seed bank at the end of the dry season in a area of caatinga suffering the process of degradation/desertification, at the municipality of IrauÃuba, CearÃ. We analysed the attributes of density, composition, diversity and richness of species as well as germination dynamics. The collections were realized in three areas, at Formigueiro, Cacimba Salgada I and Cacimba Salgada II farms. In each area, we sampled a seed bank at soil level in the experimental portion (fallow) and at the continuous use portion (control). Each portion of each area was divided in sixteen portions of 10 x 10 m, from which were drawn five portions for the study of the seed bank at soil level. In the center of each one of the five portions of 100 m2, a soil sample of 0,25 m2 was removed. The density and the composition of the seed bank at the soil level were analysed using the plantule outgrowth in greenhouse. The bank was composed primarily by therophytes. The densities found were 592, 1804, 2080 seeds/m2 for the experimental portions 1, 2 and 3, respectively, and 680, 1288 and 1408 seeds/m2 for the control portions 1, 2 and 3, respectively. Regarding the richness parameter, we found equal values for both the experimental and control portions (8 and 2 for areas 1 and 2, respectively); area 3 presented greater richness in the fallow portion (15 and 10 for the control and experimental portions, respectively). The equability values of the experimental portions were equal to 0,751, 0,041 and 0,740 for areas 1,2 and 3 respectively and of 0,613, 0,054 and 0,603 for areas 1,2 and 3 of the control portions. Regarding diversity, the values for the experimental portions 1, 2 and 3 were 1,562, 0,028 and 2,004, respectively, and 1274, 0,038 and 1,388 for the control portions 1,2 and 3, respectively, which reveals a major diversity for the areas of fallow, with exception of area 2. The raising diversity and density demonstrate the occurrence of regeneration of the herbaceous component in the fallow areas.
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Mancal, Ansu. "Adaptive capacity of communities in the areas susceptible to desertification in State of CearÃ." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13533.
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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorThe search for improvements rooted in the skills and resources of the direct beneficiaries is a strategic tool for development given level of commitment, independence and the local empowerment, especially in regions where people face serious problems such as drought. Being a recurring phenomenon of high economic and social impacts and wide geographic coverage in the State of CearÃ, it becomes a challenge both political and academic to find solutions to mitigate the damage and increase the capacity to take benefit from the opportunities that arise; revealing the need to understand how people exposed to this phenomenon adapt to live as best as possible within the constraints in terms of available resources, in other words, understand the Adaptive Capacity of people exposed to this situation. Thus, the objective of this work was to investigate the Adaptive Capacity level of rural communities inserted in the Areas Susceptible to Desertification (ASDs) of State of CearÃ. The Adaptive Capacity Index (ICA) resulted from the aggregation of four capitals (Social, Human, Natural and Economic) weighted according to their importance defined by the Analytic Hierarchy Process (AHP) based on the results of the Delphi methodology. Between the four capitals that constitute the Adaptive Capacity of rural communities in relation to droughts in the ASDs of the State of CearÃ, the Social Capital is the best that communities have and Human Capital is the weakest component. It is concluded that the rural communities of ASDs of the State of Cearà have an average level of Adaptive Capacity in relation to droughts and Human Capital is the most critical determinant of it.
A busca das melhorias enraizada nas habilidades e recursos dos beneficiÃrios diretos constitui uma ferramenta estratÃgica para promover o desenvolvimento dado nÃvel de comprometimento, a independÃncia e o empoderamento local, principalmente nas regiÃes onde se deparam graves problemas como as secas. Sendo um fenÃmeno recorrente, de altos impactos econÃmicos e sociais e de grande abrangÃncia no Estado do CearÃ, torna-se um desafio tanto polÃtico quanto acadÃmico encontrar soluÃÃes que mitiguem os danos causados e aumentem a capacidade de aproveitamento das oportunidades que surgem; revelando a necessidade de entender a forma como os sujeitos sociais expostos a esse fenÃmeno se adaptam para conviver da melhor forma possÃvel dentro das limitaÃÃes em termos de recursos disponÃveis, em outras palavras, compreender a Capacidade Adaptativa das pessoas expostas a essa situaÃÃo. Assim, objetivou-se neste trabalho investigar o nÃvel de Capacidade Adaptativa das comunidades rurais inseridas nas Ãreas SusceptÃveis à DesertificaÃÃo (ASDs) no Estado do CearÃ. O Ãndice de Capacidade Adaptativa (ICA) resultou da agregaÃÃo dos Ãndices de quatro capitais (Social, Humano, Natural e EconÃmico) ponderados de acordo com suas importÃncias definidas pelo mÃtodo de AnÃlise HierÃrquica do Processo (AHP) baseado nos resultados obtidos da metodologia Delphi. Dos quatro capitais que constituem a Capacidade Adaptativa das comunidades rurais em relaÃÃo Ãs secas nas ASDs do Estado do CearÃ, o Capital Social à o que as comunidades apresentam maior avanÃo e o Capital Humano à o mais fraco dos componentes. Conclui-se que as comunidades rurais das ASDs do Estado do Cearà possuem um nÃvel mÃdio da Capacidade Adaptativa em relaÃÃo Ãs secas e o Capital Humano à o determinante mais critico da mesma
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Oune, Omar. "Monitoring desertification in south west Tripoli using multi-temporal remotely sensing data and GIS." Thesis, University of Dundee, 2006. https://discovery.dundee.ac.uk/en/studentTheses/f3249ca1-bcc8-42fb-a88b-fc6382a8f4fd.
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Remotely sensed data has potential value for vegetation change detection and mapping in arid/semi-arid environments, which can be used and analysed to extract information relevant to the understanding of useful information for the study of desert environments and desertification monitoring, assessment and mapping. In Libya, the vast agricultural development which occurred during the last decades was accompanied by desertification ofdifferent areas. Desertification varied in type and degree according to the geographical site, irregularity of rainfall and the prevalence of strong wind which significantly affects the stability of the fragile ecosystem. The potential of this study was to offer answers to the understanding of desertification indicators and has identified criteria for desertification assessment and the creation of land degradation maps using remote sensing data and a geographic information system (GIS). The indicators which mainly impact the study area are wind erosion, vegetation degradation, salinization, and deterioration of water resources etc. Landsat TM imagery has been used as a source of data to monitor land cover and its change over large areas.In this study, multi-temporal Landsat TM imagery has been used in order to map land cover and their changes during five-year intervals from 1988 to 2000. This was achieved by using a soil adjusted vegetation index formula to detect vegetation Thealgorithm classification technique has been used to map vegetation cover, Eolian Mapping (EM) vegetation of various densities, by used the Soil Adjusted Vegetation Index (SA VI) images: TM 1988, TM 1992, TM 1996 and TM 2000. The results of this technique show areas that have vulnerability to wind erosion susceptibility. and change detection algorithm has been used to calculate the vegetation changes in theperiod from 1988 to 2000. This is therefore one land degradation factor that can be created from remotely sensed data. The analysis clearly demonstrates a net decrease in vegetation cover. This situation exemplifies the deterioration of the naturalvegetation cover. The information derived from remotely sensed data has beenintegrated in a GIS to identify relevant factors for developing a spatial model for desertification assessment and mapping. A Geographic Information System was used to combine and interpret a range of parameters (land cover, soil type, topography,climate, etc.).This This study presents an efficient methodology to delineate the land degradation factors in study area, in a GIS environment. In this study have used one of the multi-criteria decision-making techniques, Analytical Hierarchical Process (AHP) which provides a systematic approach for assessing and integrating the impact of various factors,involving several levels. The methodology has been present for computing a composite index of land degradation factors derived from topographical, land cover, soil type and climate data. All data are finally integrated in a GIS environment to prepare a final desertification map. This land degradation factors computed from AHP method not only considers susceptibility of each area to emphasize thevulnerability of land to erosion but also takes into account the factors that are related to desertification.
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Ahmadzadeh, M. R. "Reasoning with uncertainty in remote sensing." Thesis, University of Surrey, 2001. http://epubs.surrey.ac.uk/804/.
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Annaklycheva, Jamal. "Combating desertification in Turkmenistan on the grass roots level example of the central karakum desert /." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=964465272.
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Lee, Fung, and 李峯. "Lay environmental perceptions and their policy implications for mitigating desertification in Minqin County, Gansu Province." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B29227318.
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Pinheiro, Renata Aline Bezerra. "Analysis Process Degradation / Desertification in Basin Creek Warlock Based on DFC, Municipality of Jaguaribe - CearÃ." Universidade Federal do CearÃ, 2011. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=9013.
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FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgicoThis research discusses the problem of degradation / desertification in the in the Feiticeiro stream basin. With an area of 236 KmÂ, is located northwest from the city of Jaguaribe, Ceara, inserted in the Jaguaribe river basin, which has a total area of 75.669 km Â. This study was developed based in the methodology of physical conservationist diagnosis, with the aim of determining the potential for environmental degradation of the basin from the analysis of physical nature: climate index, rainfall erosivity, soil erodibility , average slope of the land, drainage density and index of vegetation cover. With the use of satellite images it was found the state of degradation of vegetation cover through the Normalized Difference Vegetation Index (NDVI). As the risks of anthropogenic desertification process are related to the type and intensity of use of natural resources and the consequences of that directly affect the population, there was a socioeconomic diagnosis from satellite images and data of agricultural production to analyze for use and occupation soil, as well as census data to analyze the population dynamics in relation to migration processes. The results may imply that there was an increase in vegetation cover, giving thus higher rates of protection in relation to risk of physical deterioration and degradation of vegetation. Also occurred between the years in question, the reduction of sites for agricultural use, deducing that there is indeed an indication of improvement in vegetation cover, which is consistent with the variation between different levels of environmental degradation / desertification. Thus, the environmental status of Feiticeiro Stream Basin needs further research to clarify the specific causes of this process of degradation / desertification, and actions to mitigate and combat the problem of desertification.
Esta pesquisa aborda a problemÃtica da degradaÃÃo/desertificaÃÃo da bacia do riacho Feiticeiro. Com uma Ãrea de 236 kmÂ, localiza-se na porÃÃo noroeste do municÃpio de Jaguaribe-CearÃ, inserida na bacia do rio Jaguaribe, que tem uma Ãrea total de 75.669 KmÂ. Este estudo foi desenvolvido à luz da metodologia do DiagnÃstico FÃsico Conservacionista (DFC), com o objetivo de determinar o potencial de degradaÃÃo ambiental da bacia a partir da anÃlise de parÃmetros fÃsicos naturais: Ãndice climÃtico, erosividade da chuva, erodibilidade do solo, declividade mÃdia do terreno, densidade de drenagem fluvial e Ãndice de cobertura vegetal. Com o uso de imagens de satÃlite verificou-se o estado de degradaÃÃo da cobertura vegetal atravÃs do Ãndice de VegetaÃÃo por DiferenÃa Normalizada (NDVI). Como os riscos do processo de desertificaÃÃo antrÃpica estÃo relacionados ao tipo e intensidade de uso dos recursos naturais e as consequÃncias desta afetam diretamente a populaÃÃo, realizou-se um diagnÃstico socioeconÃmico a partir de imagens orbitais e dados da produÃÃo agropecuÃria para anÃlise de uso e ocupaÃÃo do solo, assim como censos populacionais para analisar a dinÃmica populacional em relaÃÃo aos processos migratÃrios. Os resultados permitem inferir que houve um aumento da cobertura vegetal, apresentando, desta forma, melhores Ãndices de proteÃÃo em relaÃÃo aos riscos de degradaÃÃo fÃsica e de degradaÃÃo da vegetaÃÃo. Ocorreu, tambÃm, entre os anos verificados, a reduÃÃo das Ãreas destinadas ao uso agropecuÃrio, deduzindo-se que hÃ, de fato, indicaÃÃo de melhoria na cobertura vegetal, que condiz com a variaÃÃo entre diferentes nÃveis de degradaÃÃo ambiental/desertificaÃÃo. Deste modo, o estado ambiental da bacia do riacho Feiticeiro necessita de mais pesquisas especÃficas para esclarecer as causas desse processo de degradaÃÃo/desertificaÃÃo, assim como aÃÃes para mitigaÃÃo e combate da problemÃtica da desertificaÃÃo.
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Wang, Guiwei. "Automatic information extraction and prediction of karst rocky desertification in Puding using remote sensing data." Thesis, Högskolan i Gävle, Samhällsbyggnad, GIS, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-23988.
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Karst rocky desertification (KRD) is one kind of severe environmental problem existing in southwest of China. Reveal KRD condition is vital to solve the problem. A way to address the problem is by identifying KRD areas, so that policy-makers and researchers may get a better view of the issue and know where the areas affected by the problem are located. The study area is called Puding which is a county located in the central part of Guizhou province. Based on Landsat data, by using GIS and RS techniques, KRD information of Puding was extracted. Furthermore, the study monitored decades of change of the environmental problem in Puding and predicted possible condition in the future. Other researchers and decision makers may get a better view of the issue from the study results. In addition to Landsat data, other used data includes: ASTER Global digital elevation model data, Modis data, Google Earth data and other thematic maps. In the study, expert classification system and spectral features based model two methods were applied to extract KRD information and compare with each other. Their classified rules were taken from previous studies separately. Necessary preprocessing procedures such as atmospheric correction and geometrical correction were performed before extraction. After extraction relevant results were evaluated and analyzed. Predictions were made by cellular automata Markov module. Based on extracted KRD results, the distribution, percentage, change, and prediction of KRD conditions in Puding were presented. The results of the accuracy evaluation showed that the spectral features based model had acceptable performance. However, the KRD results extracted by expert classification system method were poor. The extracted KRD results, including KRD maps and the prediction map, both indicated that KRD areas in Puding were decreased from 1993 (spring) to 2016 (spring) and suggested to pay more attention to KRD areas changes with the seasons
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Kong, Taryn M. "Understanding Land Management and Desertification in the South African Kalahari with Local Knowledge and Perspectives." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/268615.
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Desertification, or land degradation in drylands, is a serious environmental problem in South Africa with tremendous socio-economic consequences. Land users' perspectives on land management practices and knowledge about their rangelands have been poorly represented in the discourse of land degradation in South Africa. We addressed this knowledge gap by examining three participatory methods to capture local knowledge and perspectives, as well as the relation between knowledge, attitude and practice status relative to three land management actions done by livestock farmers in the South African Kalahari. Photo elicitation captured a greater level of detail and new information compared to semi-structured interviews alone, while enhancing researchers' understanding of farmers' knowledge and perception in multiple ways. The photovoice group discussions led to farmers' engagement in reflective dialogues, which facilitated mutual learning among the farmers. We found that a high level of knowledge and positive attitude alone did not always result in actual full scale practice. Situational factors such as limited financial resources, inadequate farm infrastructure, farm size, and land tenure were given by farmers as constraints or challenges to their land management. We further examined how effective local knowledge and remotely sensed data were in assessing the veld condition in the Kalahari Duneveld. The farmers' assessment of veld condition corresponded to field measured grass, shrub and bare ground cover. The three vegetation metrics calculated from remotely sensed images (i.e., Normalized Difference Vegetation Index (NDVI), Soil-Adjusted Vegetation Index (SAVI), and the tasseled cap greenness) all correlated poorly to the measured vegetation cover because of the excess spectral noise caused by the high iron oxide content in the Kalahari sand. Local perspectives and knowledge have potential to augment traditional ground-based rangeland assessment and contribute in the combat against desertification by offering a more holistic view of land management.
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AFRASINEI, GABRIELA MIHAELA. "Study of land degradation and desertification dynamics in North Africa areas using remote sensing techniques." Doctoral thesis, Università degli Studi di Cagliari, 2016. http://hdl.handle.net/11584/266730.
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In fragile-ecosystem arid and semi-arid land, climatic variations, water scarcity and human pressure
accelerate ongoing degradation of natural resources. In order to implement sustainable
management, the ecological state of the land must be known and diachronic studies to monitor and
assess desertification processes are indispensable in this respect. The present study is developed in
the frame of WADIS-MAR (www.wadismar.eu). This is one of the five Demonstration Projects
implemented within the Regional Programme “Sustainable Water Integrated Management (SWIM)”
(www.swim-sm.eu ), funded by the European Commission and which aims to contribute to the
effective implementation and extensive dissemination of sustainable water management policies
and practices in the Southern Mediterranean Region. The WADIS-MAR Project concerns the
realization of an integrated water harvesting and artificial aquifer recharge techniques in two
watersheds in Maghreb Region: Oued Biskra in Algeria and wadi Oum Zessar in Tunisia.
The WADIS MAR Project is coordinated by the Desertification Research Center of the University
of Sassari in partnership with the University of Barcelona (Spain), Institut des Régions Arides
(Tunisia) and Agence Nationale des Ressources Hydrauliques (Algeria) and the international
organization Observatorie du Sahara et du Sahel. The project is coordinated by Prof. Giorgio
Ghiglieri. The project aims at the promotion of an integrated, sustainable water harvesting and
agriculture management in two watersheds in Tunisia and Algeria. As agriculture and animal
husbandry are the two main economic activities in these areas, demand and pressure on natural
resources increase in order to cope with increasing population’s needs. In arid and semiarid study
areas of Algeria and Tunisia, sustainable development of agriculture and resources management
require the understanding of these dynamics as it withstands monitoring of desertification
processes.
Vegetation is the first indicator of decay in the ecosystem functions as it is sensitive to any
disturbance, as well as soil characteristics and dynamics as it is edaphically related to the former.
Satellite remote sensing of land affected by sand encroachment and salinity is a useful tool for
decision support through detection and evaluation of desertification indicating features.
Land cover, land use, soil salinization and sand encroachment are examples of such indicators that
if integrated in a diachronic assessment, can provide quantitative and qualitative information on the
ecological state of the land, particularly degradation tendencies. In recent literature, detecting and
mapping features in saline and sandy environments with remotely sensed imagery has been reported
successful through the use of both multispectral and hyperspectral imagery, yet the limitations to
both image types maintain “no agreed-on best approach to this technology for monitoring and
mapping soil salinity and sand encroachment”. Problems regarding the image classification of
features in these particular areas have been reported by several researchers, either with statistical or
neural/connectionist algorithms for both fuzzy and hard classifications methods.
In this research, salt and sand features were assessed through both visual interpretation and
automated classification approaches, employing historical and present Landsat imagery (from 1984
to 2015).
The decision tree analysis was chosen because of its high flexibility of input data range and type,
the easiness of class extraction through non-parametric, multi-stage classification. It makes no a
priori assumption on class distribution, unlike traditional statistical classifiers. The visual
interpretation mapping of land cover and land use was undergone according to acknowledged
standard nomenclature and methodology, such as CORINE land cover or AFRICOVER 2000,
Global Land Cove 2000 etc. The automated one implies a decision tree (DT) classifier and an
unsupervised classification applied to the principal components (PC) extracted from Knepper ratios
composite in order to assess their validity for the change detection analysis. In the Tunisian study
area, it was possible to conduct a thorough ground truth survey resulting in a record of 400 ground
truth points containing several information layers (ground survey sheet information on various land
components, photographs, reports in various file formats) stored within the a shareable standalone
geodatabase. Spectral data were also acquired in situ using the handheld ASD FieldSpec 3 Jr. Full
Range (350 – 2500 nm) spectroradiometer and samples were taken for X-ray diffraction analysis.
The sampling sites were chosen on the basis of a geomorphological analysis, ancillary data and the
previously interpreted land cover/land use map, specifically generated for this study employing
Landsat 7 and 8 imagery. The spectral campaign has enabled the acquisition of spectral reflectance
measurements of 34 points, of which 14 points for saline surfaces (9 samples); 10 points for sand
encroachment areas (10 samples); 3 points for typical vegetation (halophyte and psammophyte) and
7 points for mixed surfaces.
Five of the eleven indices employed in the Decision Tree construction were constructed throughout
the current study, among which we propose also a salinity index (SMI) for the extraction of highly
saline areas. Their application have resulted in an accuracy of more than 80%. For the error
estimation phase, the interpreted land cover/use map (both areas) and ground truth data (Oum
Zessar area only) supported the results of the 1984 to 2014 salt – affected areas diachronic analysis
obtained through both automatic methods. Although IsoDATA classification maps applied to
Knepper ratios Principal Component Analysis has proven its good potential as an approach of fast
automated, user-independent classifier, accuracy assessment has shown that decision tree outstood
it and was proven to have a substantial advantage over the former. The employment of the Decision
Tree classifier has proven to be more flexible and adequate for the extraction of highly and
moderately saline areas and major land cover types, as it allows multi-source information and
higher user control, with an accuracy of more than 80%.
Integrating results with ancillary spatial data, we could argue driving forces, anthropic vs natural, as
well as source areas, and understand and estimate the metrics of desertification processes. In the
Biskra area (Algeria), results indicate that the expansion of irrigated farmland in the past three
decades contributes to an ongoing secondary salinization of soils, with an increase of over 75%. In
the Oum Zessar area (Tunisia), there was substantial change in several landscape components in the
last decades, related to increased anthropic pressure and settlement, agricultural policies and
national development strategies. One of the most concerning aspects is the expansion of sand
encroached areas over the last three decades of around 27%.
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RIBEIRO, Eberson Pessoa. "Mudanças ambientais e desertificação na bacia hidrográfica do rio Pajeú." Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/17527.
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A bacia hidrográfica do rio Pajeú, por ser uma área localizada em uma região semiárida, torna–se mais vulnerável e susceptível aos efeitos das mudanças ambientais e do processo de desertificação, com sérias implicações econômicas e socioambientais. Assim, a presente Tese teve como objetivo geral identificar e avaliar os diferentes graus de susceptibilidade ambiental da bacia hidrográfica do rio Pajeú à variabilidade climática e ao processo de desertificação. Para atender ao referido objetivo foram traçados os seguintes objetivos específicos: avaliar a variabilidade espaço–temporal da precipitação na bacia hidrográfica do rio Pajeú, empregando o Índice de Anomalia de Chuva (IAC); avaliar o balanço hídrico climatológico e o grau de aridez, além de realizar o mapeamento da classificação climática da bacia hidrográfica do rio Pajeú pelo método de Thornthwaite-Mather (1955); e identificar e analisar a dinâmica espaço–temporal de parâmetros biofísicos na detecção de mudanças ambientais na bacia hidrográfica do rio Pajeú com aplicação de alguns componentes do algoritmo SEBAL. Dessa maneira, os procedimentos metodológicos empregados foram: o Índice de Anomalia de Chuva (IAC) por ser uma técnica utilizada para caracterizar e monitorar a variabilidade espaço–temporal pluviométrica; o Balanço Hídrico Climatológico (BHC) e classificação climática de Thornthwaite-Mather (1955) por possibilitar a determinação do regime hídrico de uma localidade, permitindo avaliar a quantidade de água no solo que pode estar disponível; e a estimativa de alguns parâmetros biofísicos para a detecção de mudanças ambientais na referida bacia hidrográfica, aplicando alguns componentes do algoritmo SEBAL por meio da utilização de produtos MODIS, além do trabalho de campo para validação dos resultados. Os resultados apresentaram uma predominância de IAC negativos para a variabilidade interanual com pontos de inflexão mais extremos nos anos chuvosos, demonstrando também que toda a bacia hidrográfica fica com índice de anomalia entre seco e muito seco. O extrato do BHC revelou elevadas taxas anuais de ETP, bem como a predominância da deficiência hídrica ao longo do ano, deficiência que aumenta em direção à foz do rio Pajeú; já os parâmetros biofísicos revelaram que a porção sul da bacia hidrográfica é a mais degradada, apresentando temperaturas mais elevadas. A partir dos parâmetros e índices avaliados, como também da pesquisa de campo, concluiu–se que a área pesquisada está susceptível a processo de desertificação, em maior grau no Núcleo de Desertificação de Cabrobó devido às condições climáticas e edáficas. No entanto, em toda a bacia hidrográfica há apenas manchas concentradas de degradação ambiental, nas quais a ação antrópica se fez mais intensa.
The Pajeú River watershed, for being an area located in a semi-arid region, is more vulnerable and susceptible to the effects of environmental changes and the desertification process, with serious economic and environmental implications. Thus, the aim of the present study was to identify and assess the different degrees of environmental susceptibility of the Pajeú River watershed to climate variability and the desertification process. For this, the following specific objectives were established: to evaluate the spatiotemporal rainfall variability in the Pajeú River watershed using the Rain Anomaly Index (RAI); to evaluate the climatic water balance and the dryness degree, to perform the mapping of the climatic classification using the Thornthwaite-Mather method (1955); and to identify and analyze the spatiotemporal dynamics of biophysical parameters in detecting environmental changes in the Pajeú River watershed by applying some SEBAL components. Thus, the methodological procedures used were: Rain Anomaly Index (RAI) because it is a technique used to characterize and monitor the rainfall spatiotemporal rainfall variability; the Climatological Water Balance (CWB) and the Thornthwaite-Mather climatic classification (1955) for enabling the determination of the water regime of a given location in order to evaluate the amount of water in the soil that may be available; and the estimation of some biophysical parameters for detecting environmental changes in this watershed by applying some SEBAL components and MODIS products, in addition to the field work to validate the results. The results showed a predominance of negative RAI for the interannual variability with more extreme inflection points in rainy years, also showing that the entire watershed presents anomaly index between dry and very dry. The CWB extract showed high annual ETP rates and prevalence of water stress throughout the year, which is a deficiency that increases toward the mouth of the Pajeú River; and the biophysical parameters revealed that the southern portion of the watershed is the most degraded, with higher temperatures. From the parameters and indexes evaluated and the field work, it was concluded that the study area is susceptible to the desertification process to a greater degree on the Desertification Center of Cabrobó due to climate and soil conditions. However, there are concentrated environmental degradation spots throughout the watershed, in which human action was more intense.
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Maillet, Mariette M. "A desert challenge, appraisal of projects to combat desertification and drought in the West African Sahel." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ36507.pdf.
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Hoang, Viet Anh. "Multi-sensor remote sensing for desertification monitoring in the dry sub-humid coastal lowland of Vietnam." Thesis, University of Newcastle Upon Tyne, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.578239.
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Desertification, even though not a new problem, in recent years has become one of the major global threats widely recognized not only by research community but also by public interest. Traditionally, the term desert is typically used to refer to vast areas of sand dune spreading over thousands miles such as in the Sahara Desert, Africa. However, in the new concept of desertification as a degradation process, today we are facing a new trend of desertification in the sub-humid regions with an accelerating rate because of deforestation, poor agricultural land use practice and overgrazing. Mapping desertification in sub-humid areas, however, is difficult due to cloud cover, poor geo- database infrastructure and limited investment. Current desertification mapping techniques are primarily developed for arid regions and are inappropriate for sub-humid areas, both in terms of scale and ecosystem characterization. There is an obvious need for new monitoring approaches developed specifically for sub-humid areas, which utilize readily available Earth observation systems in a cost effective solution. The goal of this study is to develop an imagery-based mapping method that can be used to monitor desertification in sub-humid areas of Vietnam, which is transferable to areas with similar conditions in South East Asia. Specific objectives are: 1) to characterise the desertification process in sub- humid areas from a remote sensing perspective, 2) to develop a method for desertification mapping which combines advantages of several types of satellite imagery, thus overcoming the limitations in spatial, temporal and spectral resolution of individual satellite image systems, 3) to test and evaluate the new desertification mapping method in the coastal lowlands of Vietnam. In the first step, characterising the desertification, field surveys were conducted in the coastal lowland of Vietnam to understand the background of land processes: vegetation fluctuation in savannah landscape, land use patterns and human activities, land form and soil properties. Archived remote sensing data including Landsat, ASTER, MODIS, MERIS, and different types of SAR imagery were used to investigate the spatial and spectral responses of desertification surfaces. Through this step a set of remote sensing imagery most suitable for sub-humid desertification was selected. Next, different parameters extracted from remote sensing data and their relationships with desertification features were examined. Soil temperature and vegetation index were selected as the components required to develop the Vegetation Temperature Angle Index (VTAI) algorithm. These two parameters have strong relationships with the thermal dynamics of land processes and vegetation moisture stress, thus providing a simple yet robust representation of desertification land spectrum. The methods to extract these parameters are mature and have led to standard products being available from data providers, therefore making the implementation of the mapping method simple and comparable between geographic regions. In addition a method for rapid soil moisture estimation from SAR images was investigated. Soil moisture represents a direct and measurable indicator of dryness and therefore provides an additional dimension to verify the desertification index algorithm. The Vegetation Temperature Angle Index (VTAI), and soil moisture estimation method are evaluated in the coastal lowland of Vietnam using data from ASTER and MODIS, and ENVISAT ASAR imagery. In particular, the efficiency of the VT AI index in detecting the vegetation condition and soil water availability was investigated. The results indicate that the VT AI index is simple to construct and capable of discriminating different variation in vegetation and soil, effectively identifying vegetation stress, and is able to separate inactive vegetation from bare soil. At the same time, soil moisture estimation from SAR images can be used to verify the desertification index, and to provide a weather-independent monitoring method. The VTAI and soil moisture estimation was combined into the Vegetation Temperature Angle and Moisture (VT AMI) index. The new combined index showed improved performance compared to VT AI and produced reliable results across a wider range of land cover and surface conditions. A desertification risk class map of the study area was produced from the VT AMI index. From the results of the testing project, the elements required for effective monitoring and management of sub-humid desertification are discussed in terms of optimal remote sensing imagery and land process characteristics, in order to identify areas at risk of desertification.
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Cebollero, Esther Diez. "An assessment of the use and usefulness of decision support tools in desertification policy and management." Thesis, Cranfield University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501018.
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Technology has penetrated the environmental policy and management field, as maniTesiea oy tne numoer ot compuier-Dasea uecision support loois (DSTs) developed to support the work of end users. DSTs have been reported to support communication between stakeholders, to better monitor the status of the environment, and to better assess the consequences of certain policies. The purpose of this research is to examine the use and usefulness of DSTs to desertification policy and management organisations and thereby determine if DSTs can support the work of these organisations. Five types of DSTs have been considered namely - computer simulation models (CS), computer statistical models. (ST), decision support systems (DSS), geographical information systems (GIS), and remote sensing (RS). The study puts emphasis on desertification polcy and management because (i) desertification is a very serious environmental process that has already affected more than 1.5 billion people all over the world; (ii) desertification does not show any signs of abatement; and, (III) no similar studies within this research area have been found in the literature.
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Mohamed, Tarig A. "MONITORING AND ANALYZING OF DESERTIFICATION TREND IN NORTH SUDAN USING MODIS IMAGES FROM 2000 to 2014." OpenSIUC, 2016. https://opensiuc.lib.siu.edu/theses/2044.
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Desertification is a serious threat that damages the environment in many African countries, as a result of climatic factors and population growth. This research, investigated and monitored the dynamics of the desert area in the Republic of Sudan using geographic information system (GIS) and remote sensing images. The expansion of desertification in Sudan, particularly in Darfur, Kordofan, and Alshymalia states has, increased rapidly. Many efforts have been committed to understanding its dynamics, causes, and impacts. However, the data are still lacking. In this study Moderate-resolution Imaging Spectroradiometer (MODIS) Normalized Different Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), and Gross Primary Productivity (GPP) images were acquired for the months of July, August, and September (growing seasons of the vegetation in the study area) of the years 2000, 2009, and 2014 respectively. Landsat 8 Operational Land Imager (OLI) data were used to compare and validate the result of MODIS data. Artificial Neural Network (ANN) and Spectral Mixture Analysis (SMA) techniques were utilized to produce three classification maps, and to address the issue of the mixed pixel. Post-classification change detection method was used to quantify the change that had occurred in the study area. The results show that the overall classification accuracy for the MODIS data for the year 2000, 2009, and 2014 was 79.52 %, 81.90 %, and 85.76 % respectively, and there was a significant increase in the expansion of the desert area towards the south and southwest of the study area. The temporal period between 2000 and 2009 indicated the greatest conversion of vegetation to desert area. Population growth and climatic changes such as temperature increment and precipitation variation were the major factors that led to the desert expansion. The result of this study will provide the people of Sudan with the information regarding desert area land expansion during the past 14 years, thereby raising awareness about the environmental problem in Sudan.
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Addison, Erin Heather. "Documenting Deforestation at Sidd al-Ahmar, Petra Region, Jordan." Thesis, The University of Arizona, 2006. http://hdl.handle.net/10150/193295.
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This study documented the decline of the forests of the Petra Region of Jordan, as represented at Sidd al-Ahmar, within the Petra Archaeological Park. Biogeographical and anthropological methods were employed to explore the history of the forests. Archaeology and historical narratives provided a portrait of the study area from prehistory to the early 20th century. Aerial surveys from 1924 and 2002 were analyzed to quantify changes in forest cover. Mapping and inventory of indicator species measured short-term change between 2003 and 2006. Interviews, field observation and participant observation in the tourist industry provided a socio-cultural context for quantitative analysis and for recommendations for remediation of pressures on the remaining forest. The research documents a 58% decline in tree cover between 1924-2002, and a decline of 4.23% between 2003-2006. The conclusions question concepts such as "landscape integrity" and the usefulness of non-interventionist ideology in an historic and rapidly changing region.
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Asgedom, Reda Aster. "Diskursanalys på den Etiopiska regeringens nationala handlingsplan om bekämpning av ökenspridning." Thesis, Linköping University, Department of Thematic Studies, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2607.
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In this paper discourse analysis on the Ethiopian National Action Program (NAP) to combat desertification is made. The aim is to describe how the overall image/picture of desertification, its causes, and effects and of possible solutions are presented in the NAP.
The result of this analysis shows that the main cause of desertification is human activities mainly due to the poorly developed socio-economic situation in the dryland areas. It is indicated that an excessive dependency of the rural population on the natural resources, particularly land, is the major cause of land degradation and this deterioration of land is said to have been caused by the rapid population growth, overgrazing, forest clearing as well as past government and institutional failures. In addition it is indicated that the effect of desertification usually involves ecological changes that sap land of its ability to sustain agriculture and human habitation, therefore the most serious threat to human welfare. Desertification diminishes the ability of affected countries to produce food and consequently entail the reduction of regional and global food- producing potential with impacts on world food reserves and food trade. The solution given to mitigate desertification in Ethiopia is that the present strategies are intended to combat desertification, through different action programmes such as improving knowledge on drought and desertification, basic infrastructure, institutional organisations and capacity, awareness and participation as well as empowerment of women.
The analysis also shows that priority was given to socio-economical aspect of the country not directly to combat desertification. It is suggested that in order to mitigate the land degradation, promotion of alternative livelihood is necessarily and this is reported to be achieved through industrialisation, rural credit programmes, intensification and diversification of agriculture, building awareness and access to information, enhancement of institutional organisations, participatory natural resource management, encouraging the private sector in involvement in forest development etc. Finally the analysis identifies different discourses, such as the survivalism, anthropocentrism, ecological modernisation, administrative- rationalism, economic rationalism and democratic pragmatism. Likewise the conflict that prevails between the discourses is discussed.
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Tantawi, Attia Mahmoud Mohamed el. "Climate change in Libya and desertification of Jifara Plain using geographical information system and remote sensing techniques /." [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=97597503X.
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Malatesta, Luca. "Biodiversity and ecosystems dynamics of rangelands on a climatic gradient in face of management and desertification threats." Doctoral thesis, Università degli Studi di Camerino, 2015. http://hdl.handle.net/11581/401734.
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Charrua, Helena Cristina Cochicho. "Desertificação e reversibilidade dos problemas de desertificação." Master's thesis, ISA/UL, 2014. http://hdl.handle.net/10400.5/7425.
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Mestrado em Arquitetura Paisagista - Instituto Superior de AgronomiaThe 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
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Khiry, Manal Awad. "Spectral Mixture Analysis for Monitoring and Mapping Desertification Processes in Semi-arid Areas in North Kordofan State, Sudan." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2007. http://nbn-resolving.de/urn:nbn:de:swb:14-1187262045124-42224.
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Multi-temporal remotely sensed data (MSS, TM and ETM+)were used for monitoring and mapping the desertification processes in North Kordofan State, Sudan.A liear mixture model (LMM) was adopted to analyse and the desertification proccesses by using the image endmembers. interpretation of ancillary data and field observation was adopted to verfiy the role of human impacts in the temporal changes in the study area. The findings of the study proved the powerfull of remotely sensed data in monitoring and mapping the desertification processes and come out with valuable recommendations which could contribute positively in reducing desert encroachment in the area.
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Elhadi, Hanan. "Evaluation of gum arabic reforestation as a measure for combating desertification in the gum belt area of Sudan." Weikersheim Margraf, 2008. http://d-nb.info/993761275/04.
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Stringer, Lindsay C. "Applying the United Nations Convention to Combat Desertification in Africa : scientific and land user dimensions of environmental degradation." Thesis, University of Sheffield, 2004. http://etheses.whiterose.ac.uk/13505/.
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This study takes an integrated approach using theories and methods from both the natural and social sciences to examine western scientific, government, NGO and local land user understandings of land degradation in Swaziland. Of key importance in the research is the United Nations Convention to Combat Desertification (UNCCD), which itself marks a new, integrated approach to sustainable development, promoting concepts of community participation and local level decision-making. Grounded in the theory of political ecology, these concepts are examined in the Swazi context. Local knowledges are integrated with western scientific understandings of land degradation to create hybrid understandings of environmental degradation and to examine issues such as how far, under what conditions and for whom land degradation is problematic. Understandings of soil fertility, drought, changes to woodland areas and soil erosion in three case study villages are critically assessed, as local inputs into policies addressing land degradation are evaluated and reasons behind both individual and collective actions to combat degradation are considered. Issues of access and power are found to dominate natural resource management in Swaziland, as the majority of the power is concentrated in the hands of the minority of the population. Using a community land rehabilitation project as a case study, it is discovered that concepts such as community participation and local level decision-making by democratically elected village committees can cause conflict to develop between new and traditional institutions, as new institutions challenge the traditional balance of power. It is concluded that until changes are made to broader scale governance structures, concepts advocated by the UNCCD will not be implemented to their full potential in Swaziland and this could have important social and ecological implications.
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Hill, Kara J. "Research on Preventing and Remediating the Dust Storms of China: A Case Study Investigating the Development of Salt Water Agriculture." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1306877383.
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Jin, Yutong. "Environmental Input-output Analysis and Its Application to Multi-region Studies." Thesis, The University of Sydney, 2022. https://hdl.handle.net/2123/29591.
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Our world is beleaguered by environmental and socioeconomic problems, such as natural resources degradation, natural hazards, climate change, unemployment, and inequality. Trade supply chains are recognised as important means to address environmental and socio-economic challenges. The world has benefited from trade in many ways, such as promoting economic growth, opening the global market for all countries, and creating jobs. However, trade is likely to increase environmental externalities at both national and global level. Trade can directly affect local environment through overexploitation of natural resources and substantial pollution. One reason for this is that trade is mainly driven by regions’ differing natural resource endowments. Considering the adverse environmental impact of trade and supply chains, as well as their effects on societal and economic development, domestic and international trade supply chains play a key role in addressing regional and global environmental challenges, and thus contribute to achieving Sustainable Development Goals (SDGs) – a global plan adopted by all United Nations (UN) members for a better and more sustainable future.
This thesis applies a quantitative interdisciplinary approach - multiregional input-output (MRIO) analysis to estimate the environmental and socioeconomic impacts of supply chains in three case studies: (i) calculate material footprint in four megacities of China by linking Chinese MRIO to the Global MRIO database Eora, (ii) estimate direct and indirect economic loss and spillovers of desertification in China, as well as the nutrient loss caused by desertification, by applying an improved input-output (IO)-based disaster model, (iii) investigate how Greenhouse Gas (GHG) emissions, land use, and employment will be affected by switching from petroleum-based plastics to bio-based plastics, with an improved IO technique for estimating the substitution effects of bioplastics.
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Neilson, Julia W., Katy Califf, Cesar Cardona, Audrey Copeland, Treuren Will van, Karen L. Josephson, Rob Knight, et al. "Significant Impacts of Increasing Aridity on the Arid Soil Microbiome." AMER SOC MICROBIOLOGY, 2017. http://hdl.handle.net/10150/625716.
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Global deserts occupy one-third of the Earth's surface and contribute significantly to organic carbon storage, a process at risk in dryland ecosystems that are highly vulnerable to climate-driven ecosystem degradation. The forces controlling desert ecosystem degradation rates are poorly understood, particularly with respect to the relevance of the arid-soil microbiome. Here we document correlations between increasing aridity and soil bacterial and archaeal microbiome composition along arid to hyperarid transects traversing the Atacama Desert, Chile. A meta-analysis reveals that Atacama soil microbiomes exhibit a gradient in composition, are distinct from a broad cross-section of nondesert soils, and yet are similar to three deserts from different continents. Community richness and diversity were significantly positively correlated with soil relative humidity (SoilRH). Phylogenetic composition was strongly correlated with SoilRH, temperature, and electrical conductivity. The strongest and most significant correlations between SoilRH and phylum relative abundance were observed for Acidobacteria, Proteobacteria, Planctomycetes, Verrucomicrobia, and Euryarchaeota (Spearman's rank correlation [r(s)] = >0.81; false-discovery rate [q] = <= 0.005), characterized by 10- to 300-fold decreases in the relative abundance of each taxon. In addition, network analysis revealed a deterioration in the density of significant associations between taxa along the arid to hyperarid gradient, a pattern that may compromise the resilience of hyperarid communities because they lack properties associated with communities that are more integrated. In summary, results suggest that arid-soil microbiome stability is sensitive to aridity as demonstrated by decreased community connectivity associated with the transition from the arid class to the hyperarid class and the significant correlations observed between soilRH and both diversity and the relative abundances of key microbial phyla typically dominant in global soils. IMPORTANCE We identify key environmental and geochemical factors that shape the arid soil microbiome along aridity and vegetation gradients spanning over 300 km of the Atacama Desert, Chile. Decreasing average soil relative humidity and increasing temperature explain significant reductions in the diversity and connectivity of these desert soil microbial communities and lead to significant reductions in the abundance of key taxa typically associated with fertile soils. This finding is important because it suggests that predicted climate change-driven increases in aridity may compromise the capacity of the arid-soil microbiome to sustain necessary nutrient cycling and carbon sequestration functions as well as vegetative cover in desert ecosystems, which comprise one-third of the terrestrial biomes on Earth.
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Barreto, Lucas Lopes. "Suscetibilidade ao processo de desertificação no Núcleo dos Sertões dos Inhamuns: o caso da sub-bacia do riacho do Urubu – Mucuim – Arneiroz – CE." reponame:Repositório Institucional da UFC, 2015. http://www.repositorio.ufc.br/handle/riufc/20232.
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BARRETO, Lucas Lopes. Suscetibilidade ao processo de desertificação no Núcleo dos Sertões dos Inhamuns: o caso da sub-bacia do riacho do Urubu – Mucuim – Arneiroz – CE. 2015. 152 f. Dissertação (Mestrado em geografia)- Universidade Federal do Ceará, Fortaleza-CE, 2015.Submitted by Elineudson Ribeiro (elineudsonr@gmail.com) on 2016-10-14T12:56:31Z No. of bitstreams: 1 2015_dis_llbarreto.pdf: 8830368 bytes, checksum: 1e1f96e70a62dab95b2dbaa5e004c9db (MD5)
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Watersheds are areas of significant relevance to geographical studies by witnessing the dynamic, current and previous, landscape, for harboring vast biodiversity and areas are preferably development of societies, contributing to socioeconomic and cultural activities. Because of this potential, the uses made, in some cases, not consistent with the ability to support, resulting in environmental problems. Desertification is the degradation of the quality of natural resources and socioeconomic conditions in dry lands. This degradation process has performance levels. The areas of Brazil that have higher levels of degradation are called Nuclei of Desertification. This research was developed in the sub-basin of the Urubu-Mucuim stream which has an area of 310, 771km² in the municipality of Arneiroz, located in the southwestern portion of the state of Ceará, in Nuclei of Desertification Sertões dos Inhamuns, with the aim of analyzing the performance of desertification on this sub-basin. The methodology used was the Environmental Systems with the application of Geobiofisicos indicators that helped to understand the level of existing desertification. To support this analysis, it was also used as technical field work, the application of interviews and Cartography, which contributed to the production of maps that have scales of 1: 100,000 and 1: 150,000, the satellite images used for mapping were Landsat 8 and RapidEye. The study area is likely the work of desertification; one can see that the geo-environmental characteristics and heavy duty applications made by communities contribute to the framework of degradation. However in some areas the welfare programs mitigate the environmental degradation processes, and there is thus a need for rational use of natural resources policies to mitigate and live with the problem of desertification.
As bacias hidrográficas são áreas de relevância significativa para estudos geográficos por testemunharem as dinâmicas, atuais e pretéritas, da paisagem, por abrigarem vasta biodiversidade e por serem áreas preferencialmente de desenvolvimento das sociedades, contribuindo para atividades socioeconômicas e culturais. Devido a estas potencialidades, os usos feitos, em alguns casos, não condizem com a capacidade de suporte, resultando em problemas ambientais. A desertificação é a degradação da qualidade dos recursos naturais e das condições socioeconômicas nas terras secas. Esse processo de degradação tem níveis de atuação. As áreas do território brasileiro que possuem maiores níveis de degradação são denominadas de Núcleos de Desertificação. A presente pesquisa foi desenvolvida na sub-bacia hidrográfica do riacho do Urubu-Mucuim que possui uma área de 310, 771km², no município de Arneiroz, localizado na porção sudoeste do Estado do Ceará, no Núcleo de Desertificação dos Sertões dos Inhamuns, tendo o objetivo de analisar a atuação da desertificação sobre esta sub-bacia. A metodologia utilizada foi a dos Sistemas Ambientais com a aplicação dos Indicadores Geobiofísicos, que contribuíram para entender o nível de desertificação existente. Para subsidiar esta análise, também foram utilizadas como técnicas o trabalho de campo, a aplicação de entrevistas e a Cartografia, que contribuíram na confecção dos mapas que possuem escalas de 1:100.000 e 1:150.000, as imagens de satélites utilizadas para o mapeamento foram Landsat 8 e Rapideye. A área estudada está susceptível a atuação da desertificação, pode-se perceber que as características geoambientais e os intensos usos feitos pelas comunidades contribuem com o quadro degradação. Porém em algumas áreas os programas assistencialistas atenuam os processos de degradação ambiental, havendo a necessidade de políticas de uso racional dos recursos naturais para mitigar e conviver com a problemática da desertificação.