Tesis sobre el tema "Écosystèmes – Télédétection"
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Touré, Ibra. "Contribution à l'analyse et à la cartographie de divers écosystèmes sahéliens par l'utilisation de la télédétection et des systèmes d'informations géographiques". Nice, 1994. http://www.theses.fr/1994NICE2018.
Texto completoThe Sahel is manifestly the only geographical zone where all efforts aimed at harnessing and managing natural resources are hindered by the insufficiency, or more commonly. The lack, of reliable cartographie data. Moreover. Trational maps on paper increasingly fail to meet the meeds of spatial analysis and aid in planning. This thesis focusses ont the analysis of sahelian ecosystems, and employs a methodological design, based on new techniques of digital cartography, that combines remote data from satellites and geographical information systems. Part one of the thesis outlines the major geographical features of the Sahel zone. Emphasis is placed on the eco-climatic factors and their impact on specitfic ecosystems that are fairly representative of this zone - the "brousse tigrée" of the Tagant-Mauritania area, the Senegal valley and the mangroves of the Saloum river in Senegal. The principles and methods of remote sensing are also recalled, as well as the advantages of sattellite images in the monitoring and analysis of sensitive and poorly known environements. Part two deals with the synergy between remote sensing and geographical information systems. The advantages of each of these two techniques are highilighted, and the study proposes an integration methodology geared towards a better cartographic approach to dynamic ecosystems. Part three demonstrates the efficiency of a geographical information system incorporating satellite images. This procedure is illustrated with reference to the mangroves of the Saloum river mouth. The study finally proposes a series of recommendations and propositions that serve a framework for the transfer and application of these new techniques in the countries composing the Sahel
Kristóf, Dániel. "Application de la télédétection pour la cartographie et le suivi des écosystèmes forestiers : application à la forêt hongroise". Toulouse 3, 2005. http://www.theses.fr/2005TOU30233.
Texto completoMonitoring subtle changes over long time periods using numerous satellite images is a challenging task. In this thesis, possibilities and limitations of the available data and methods are presented through three case studies. In the first one, the objective is to create a digital vegetation map by using a multispectral satellite image. In the second study, forestry applications of novel very high resolution satellite images are examined. Geometric correction and special data extraction methods are of interest. The third case study aims at the quantification of the effects of a water diversion on local forested ecosystems in the north-western part of Hungary. Numerous satellite images are used to carry out quantitative change analysis. The long study period, the large number of images and the objectives of the study require the application and testing of several methods, and the elaboration of new methods, especially for geometric and radiometric corrections and data fusion
Bellet, Valentine. "Intelligence artificielle appliquée aux séries temporelles d'images satellites pour la surveillance des écosystèmes". Electronic Thesis or Diss., Université de Toulouse (2023-....), 2024. http://www.theses.fr/2024TLSES013.
Texto completoIn the context of climate change, ecosystem monitoring is a crucial task. It allows to better understand the changes that affect them and also enables decision-making to preserve them for current and future generations. Land use and land cover (LULC) maps are an essential tool in ecosystem monitoring providing information on different types of physical cover of the Earth's surface (e.g. forests, grasslands, croplands). Nowadays, an increasing number of satellite missions generate huge amounts of free and open data. In particular, satellite image time series (SITS), such as the ones produced by Sentinel-2, offer high temporal, spectral and spatial resolutions and provide relevant information about vegetation dynamics. Combined with machine learning algorithms, they allow the production of frequent and accurate LULC maps. This thesis is focused on the development of pixel-based supervised classification algorithms for the production of LULC maps at large scale. Four main challenges arise in an operational context. Firstly, unprecedented amounts of data are available and the algorithms need to be adapted accordingly. Secondly, with the improvement in spatial, spectral and temporal resolutions, the algorithms should be able to take into account correlations between the spectro-temporal features to extract meaningful representations for the purpose of classification. Thirdly, in wide geographical coverage, the problem of non-stationarity of the data arises, therefore the algorithms should be able to take into account this spatial variability. Fourthly, because of the different satellite orbits or meteorological conditions, the acquisition times are irregular and unaligned between pixels, thus, the algorithms should be able to work with irregular and unaligned SITS. This work has been divided into two main parts. The first PhD contribution is the development of stochastic variational Gaussian Processes (SVGP) on massive data sets. The proposed Gaussian Processes (GP) model can be trained with millions of samples, compared to few thousands for traditional GP methods. The spatial and spectro-temporal structure of the data is taken into account thanks to the inclusion of the spatial information in bespoke composite covariance functions. Besides, this development enables to take into account the spatial information and thus to be robust to the spatial variability of the data. However, the time series are linearly resampled independently from the classification. Therefore, the second PhD contribution is the development of an end-to-end learning by combining a time and space informed kernel interpolator with the previous SVGP classifier. The interpolator embeds irregular and unaligned SITS onto a fixed and reduced size latent representation. The obtained latent representation is given to the SVGP classifier and all the parameters are jointly optimized w.r.t. the classification task. Experiments were run with Sentinel-2 SITS of the full year 2018 over an area of 200 000 km^2 (about 2 billion pixels) in the south of France (27 MGRS tiles), which is representative of an operational setting. Results show that both methods (i.e. SVGP classifier with linearly interpolated time series and the spatially kernel interpolator combined with the SVGP classifier) outperform the method used for current operational systems (i.e. Random Forest with linearly interpolated time series using spatial stratification)
Thiam, Sidy. "Suivi des écosystèmes sahéliens à partir de la télédétection satellitaire : application au delta intérieur du Niger (Mali) et à la région du lac de Guiers (Sénégal)". Paris 1, 1997. http://www.theses.fr/1997PA010696.
Texto completoCadamuro, Laurent. "Structure et Dynamique des écosystèmes inondables (forêt marécageuse, mangrove) du bassin du Sinnamary (Guyane Française)". Phd thesis, Université Paul Sabatier - Toulouse III, 1999. http://tel.archives-ouvertes.fr/tel-00007798.
Texto completoKaptue, Tchuente Armel. "Cartographie des écosystèmes et paramètres biophysiques satellitaires pour l'étude des flux hydriques sur le continent africain". Toulouse 3, 2010. http://thesesups.ups-tlse.fr/994/.
Texto completoIn the context of climate change, the aim of this study is to characterize the heterogeneity of the African continent in order to provide some elements to better understand and quantify surfaces process acting on hydric fluxes. This work is intented to update the double ECOCLIMAP-I database which is constituted by a land cover map and a dassets of land biophysical parameters. To this end, we use remotely sensed data acquired by the latest generation sensors MODIS and SPOT/VEGETATION between 2000 and 2007. During the first step, two methods of classifications has been developed for the mapping of different ecosystems. The first method, which is supervised, is obtained by combining information provided by the both global land cover map GLC2000 and ECOCLIMAP-I using an interactive analysis of MODIS leaf area index (LAI). It has been performed in the framework of the AMMA project to discriminate ecosystems over the western African Region. The second method is hybrid in that it combines k-NN clustering, hierarchical principles and the Fast Fourier Transform (FFT) on the basis of multi-annual NDVI data from SPOT/VEGETATION to identify ecosystems at the whole African continent. Then, methods for the estimation of land surface biophysical variables such as albedo, fractional vegetation cover and leaf area index has been developed and/or applied over the mainland. A statistical approach allows us to determine the contribution of bare soil albedo and vegetation albedo to the constitution of albedo as required in land surface models. After the application of the latter approach over the western african region, we demonstrate the robustness of the method by applying it over the entire mainland. The sensitivity of two land surface scenarios was studied by analysing two simulations with the same atmospheric forcing over the western African Region:one using the ECOCLIMAP-I classification and another using the new physiographic forcing specifically developed over the western African region. Heat and latent flux are mainly driven by the fractional vegetation coverage. The land surface model ISBA can be used to predict the impact of land cover change and accordingly the anthropic pressure on hydric fluxes
Amram, Olivier. "Régionalisation du bilan hydrique à l'aide de mesures satellitaires pour l'étude du fonctionnement des écosystèmes d'Afrique de l'Ouest". Toulouse 3, 1996. http://www.theses.fr/1996TOU30274.
Texto completoEspel, Diane. "Développement d'une boîte à outils pour comprendre et prédire la dynamique spatiale et temporelle des macrophytes submergés : application aux écosystèmes fluviaux". Thesis, Toulouse, INPT, 2020. http://www.theses.fr/2020INPT0083.
Texto completoBecause of their multiple ecological roles, macrophytes are an important component of hydrosystems, and are thus essential to conserve. However, during the summer season, high densities of submerged species cause recurrent problems in certain rivers, especially in urban areas for users and managers, and can have negative consequences for ecosystem health. In a context of global change, the overgrowth of submerged macrophytes calls for new tools to better understand the dynamics of macrophytes meadows and to predict their dynamics according to different environmental scenarios. In this context, this thesis aims to develop a toolbox accompanying a multispecific mechanistic model for the production of submerged aquatic plants, the DEMETHER model. This model simulates the spatial and temporal biomass dynamics for two common species of the mid-part of the Garonne (Myriophyllum spicatum and Ranunculus fluitans) over river section of about one kilometer. It takes into account the variability of local hydromorphological and meteorological conditions. To do this, the model requires determining certain ecophysiological parameters and having spatialized biomass data for its calibration, as well as bathymetric and substrate data. The first phase of this work then consisted in field surveys to characterize the study site and in developing numerical or experimental tools for the acquisition of these data. The first tool developed aims to monitor submerged macrophytes by remote sensing. The method explored here confirmed the potential of high spatial resolution (50 cm) multispectral imagery of Pléiades satellites, processed by machine learning algorithms, to map the distribution of macrophyte beds and quantify their biomass in situ. This approach has also led us to propose an optimized sampling strategy for macrophytes in large rivers for future investigations. This work opens up interesting perspectives for applying the method to drone imagery, and continuing its development for automated monthly monitoring. In parallel, a tool was developed for measuring physiological parameters via oximetry and applied to the two species of interest. The data obtained provide information in particular on the photosynthetic and respiratory capacities of each species in response to limiting factors (light, temperature). The second phase of this work consisted in applying the DEMETHER model to explore different climate change scenarios. Simulations of the macrophyte dynamics in terms of biomass were carried out for current thermal conditions and for a foreseeable rise in temperatures by 2041-2070. The results showed the importance of the temperature sensitivity of certain physiological processes to explain the distribution patterns of the two species studied, highlighting the interest of mechanistic modelling to understand the structuring of macrophyte communities. The first results obtained with this toolbox confirmed its functionality. However, in order to extend its application range, each of the tools developed during the thesis will need to be further improved, in particular to refine the calibration of the DEMETHER model. Specific suggestions have been made to this aim
Kone, Nicolas. "Contribution à l'étude du fonctionnement des écosystèmes naturels en zone soudano-sahélienne (cas du Burkina Faso). Approche de la dynamique de la sécheresse par télédétection". Toulouse 3, 1992. http://www.theses.fr/1992TOU30067.
Texto completoJauffret, Sandrine. "Validation et comparaison de divers indicateurs des changements à long term dans les écosystèmes méditerranéens arides : application au suivi de la désertification dans le Sud tunisien". Aix-Marseille 3, 2001. http://www.theses.fr/2001AIX30066.
Texto completoAs many rangelands surrounding the Mediterranean Basin, the Tunisian arid zone, characterised by scattered steppic vegetation, is commonly viewed as degraded landscapes. In Arid Mediterranean regions, vegetation dynamics is indeed affected by hunian and non-human disturbances and stresses which induce desertification processes. In this context, the objectives of this research were to identify and validate various indicators of long term changes to provide information useful for the management of arid lands. The study is focussed on the understanding of 1) the structure and functioning of ecosystems and 2) the changes that occur in space and time in response to degradation. The ecological indicators allow us to describe different organisation levels from species to the ecosystem and the landscape. The diachronic comparison of vegetation maps of 1975 and 2000 allow a more complete diagnosis about the evolution of ecosystems and landscapes over the last three decades. .
Kaptue, Armel. "Cartographie des écosystèmes et paramètres biophysiques satellitaires pour l'étude des flux hydriques sur le continent africain". Phd thesis, Université Paul Sabatier - Toulouse III, 2010. http://tel.archives-ouvertes.fr/tel-00547510.
Texto completoMuñoz, Sabater Joaquín. "Assimilation de données de télédétection pour le suivi des surfaces continentales : Mise en oeuvre sur un site expérimental". Phd thesis, Université Paul Sabatier - Toulouse III, 2007. http://tel.archives-ouvertes.fr/tel-00157976.
Texto completoKabulu, Djibu Jean-Pierre. "Impacts des activités minières sur les écosystèmes forestiers au Katanga, République Démocratique du Congo". Doctoral thesis, Universite Libre de Bruxelles, 2011. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209822.
Texto completoLes résultats ont montré que l’exploitation minière et la croissance démographique sont deux facteurs de la déforestation, considérés comme les paramètres principaux du processus de changement du paysage au Katanga. L’analyse spatiale, faite grâce à la cartographie et aux systèmes d’information géographique, a permis de faire le calcul d’indices de composition et de configuration du paysage afin d’analyser la structure spatiale des forêts. La structure a été ensuite modélisée pour évaluer les impacts de concessions, des routes et des sites miniers sur la forêt. En fonction de résultats obtenus, on constate que les forêts du Katanga subissent une pression anthropique assez forte et la tendance générale de la fragmentation des forêts est inquiétante. Les habitats forestiers sont entrain d’être transformés en formations savanicoles. Les activités minières ont un impact défavorable sur les forêts de la province. La présence des plusieurs compagnies minières a favorisé l'augmentation des sites miniers et la densification du réseau routier.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Macera, Lisa. "Restauration des écosystèmes de mangroves : évaluation et amélioration des pratiques à travers une étude comparative de projets à l'échelle mondiale". Electronic Thesis or Diss., Université Côte d'Azur, 2024. http://www.theses.fr/2024COAZ2015.
Texto completoMangroves represent unique coastal social-ecosystems situated in tropical and subtropical regions worldwide. They endure both anthropogenic and natural degradations, compromising their ecological functionalities and their numerous contributions to human societies. In response to this situation, a multitude of mangrove restoration projects have been initiated. However, in the long term, a significant portion of these initiatives has failed, highlighting a lack of understanding of the ecosystem and its relationship with human societies. Within this context, this thesis primarily aims to address the following question: How can the effectiveness of mangrove ecological restoration projects be improved? Three research objectives have emerged in response: (i) to assess the restoration projects' effectiveness for nature and society, (ii) to identify gaps leading to poor practices, and finally, (iii) to propose solutions to enhance the projects. To achieve these objectives, a geographic analysis of restoration projects on a global scale was undertaken, examining each of the projects' major phases: design, implementation of restoration measures, and monitoring-evaluation. In the design phase, one of the major identified gaps is the lack of standardized pre-restoration site assessment methods accessible to managers. To address this need, the foundations of the Rapid Assessment Method for Mangroves (RAM MANGROVES) tool were developed. A bibliographic analysis, coupled with semi-structured interviews with experts and supported by a field test, led to a method consisting of 16 ecological and socio-economic descriptors, as well as a standardized field protocol.During the implementation phase, a state of the art of restoration measures and a synthesis of scientific recommendations for their improvement were carried out. This involved a comparative analysis of global restoration projects and an in-depth study of a particular case in the Philippines. These efforts highlighted the crucial importance of a systemic approach integrating ecological, social, and economic aspects to maximize the chances of a restoration project's success. They also confirmed a key point: rehabilitation of conditions conducive to mangrove development should be considered a priority, with replanting only considered if the environmental conditions favourable to the maintenance and development of mangroves have been rehabilitated or were not degraded. This work also illuminated that most scientific recommendations are not adhered to in many mangrove restoration projects.Finally, in the monitoring-evaluation phase, a significant lack of project evaluation was identified. To encourage project holders to undertake this crucial step, a high-resolution remote sensing approach is proposed. This approach was used to evaluate the evolution of the vegetation cover of six restoration sites in Costa Rica, Senegal, Benin, and the Philippines. This analysis utilizes Landsat and Sentinel images. An analysis at multiple spatial and temporal scales was conducted to ensure the robustness of the interpretations. The results revealed a high accuracy of the mapping, with an average Kappa index of 0.95, confirming the reliability of this approach.In summary, the effectiveness of mangrove restoration projects is closely linked to the quality of project design, the relevance of selected restoration measures, the active engagement of local communities, and the use of appropriate monitoring tools
Kemavo, Anoumou. "Potentialités des données de télédétection optique et radar libres d’accès pour l’évaluation et le suivi des écosystèmes forestiers tropicaux : étude de cas au Togo, en République Démocratique du Congo, en Guyane française et en République Dominicaine". Thesis, Paris Est, 2018. http://www.theses.fr/2018PESC2181/document.
Texto completoThis study aims to explore the potential of optical remote sensing and free access radar data for the assessment and monitoring of tropical, dry or wet forest ecosystems. Different test sites located in these tropical forest ecosystems have been selected. These are: the Virunga National Park in the Democratic Republic of Congo (DRC), the Oti-Keran-Mandourie Biosphere Reserve (OKM) and Togodo Wildlife Reserve (RFT) in Togo, the area around the bridge linking the city of Saint-Georges de l'Oyapock and the plain of the Kourou coast in French Guiana and the province of Monté Cristi in the Dominican Republic. Different data were used in this study: for radar images, Sentinel-1 time series, Alos-2 mosaics and, for optical images, Sentinel-2 and Landsat-8. Exogenous data such as GPS points, digital terrain models and reference maps. The methodology approach used consists of pretreatment on optical and radar images. Specific approaches, varying by study site, included: photo detailed interpretation, supervised SVM classification, forest inventory and application of allometric equations, a wavelet decomposition detection approach, a detection approach automatic changes by thresholding and the characterization of these changes. The main results are:PNVI site: land cover maps and forest, non-forest binary maps of 1987, 1997, 2007 and 2017 are produced on the PNVI. Over the 30-year period using the binary maps between 1987 and 2017 the average annual rate of deforestation is 1.07%. This high deforestation rate shows the increasing pressure on forest resources in the Virunga landscape. OKM and RFT site: a classification carried out on a combination of optical and radar images gives slightly better performances than classifications carried out on optical and radar images considered separately. The land cover maps from these classifications were used as a basis for estimating carbon stocks through forest resource assessment. At the Saint-Georges de l'Oyapock site, temporal analysis using wavelet decompositions revealed three main types of changes due to anthropogenic deforestation, seasonal changes and agricultural changes. On the site of the Monté Cristi province in the Dominican Republic, the joint analysis of radar and optical images made it possible to propose a cartography comprising 18 field-controlled land cover classes with an overall accuracy of more than 90%. Historical forest monitoring shows a decline in forest cover. At the same time, we observe a regression of the surface of mangroves between 2015 and 2018.This study has highlighted the immense potential of optical and radar remote sensing data in the characterization, mapping and monitoring of land use layers in tropical ecosystems in different regions of the world and according to seasonal conditions. While each type of remote sensing data has these discriminatory qualities and capabilities, this study has shown that the joint and combined use of two types of data significantly increases the characterization and discrimination of land-use classes and thus increases the chances of reliability of the actions to be carried out
Carlson, Bradley. "Compréhension des patrons spatiaux de diversité et de productivité chez les plantes alpines : application de l'imagerie à haute résolution dans les Alpes françaises". Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAV057/document.
Texto completoThe central aim of this thesis is to contribute to current understanding of environmental drivers of plant diversity and productivity as well as of recent changes in vegetation structure in a temperate alpine context, the French Alps. My approach draws on methods from remote sensing and plant ecology by combining plot-based measures of plant diversity and climate data with high-resolution imagery. Chapter I demonstrates the importance of quantifying snow cover duration for predicting patterns of plant taxonomic and functional diversity, and also highlights the ongoing challenge of modeling spatial gross primary productivity dynamics in alpine landscapes. In Chapter II, I explore the utility of satellite imagery for quantifying environmental conditions experienced by alpine plant communities, and further show how metrics of snow cover duration and peak productivity can be used to differentiate habitat for dominant alpine plant communities. I also explore how functional diversity mediates NDVI responses to highly contrasting snow years. Chapter III provides new evidence of recent shifts occurring in high-elevation plant communities in the French Alps in response to climate and land-use change. Analysis of the forest-grassland ecotone in the Vercors Regional Park shows a strong dynamic of forest expansion in response to overall climate warming and local shifts in grazing-related land-use practices, which supports findings from other studies conducted elsewhere in the Alps and Pyrenees. In the second part of Chapter III, for the first time I present evidence of greening dynamics in a protected area of the French Alps, the Ecrins National Park. I propose that a decrease in snow cover duration and pronounced warming occurring in the 1980s likely contributed to increased canopy productivity in high alpine contexts, and are driving long-term greening in the absence of land-use change. Taken collectively, rather than pushing a specific aspect alpine ecology forward, my work helps to fill out our working knowledge of alpine plant communities and serves to solidify a number of field-based observations by carrying out robust spatial analyses
Moinardeau, Cannelle. "L’éco-pastoralisme un outil adapté pour la gestion conservatoire des écosystèmes très anthropisés ? : le cas des digues artificielles du canal de dérivation de Donzère-Mondragon dans la vallée du Rhône (Vaucluse-Drôme, France)". Thesis, Avignon, 2018. http://www.theses.fr/2018AVIG0345/document.
Texto completoThe main objective of the thesis was to characterize the impacts of different types of pastoral management (cattle, horses, goats) on "new ecosystems" plant communities. Our experimentations were conducted in highly anthropized dykes and embankments of the Donzère-Mondragon reserve in the lower Rhone valley. Various tools were used (i.e. vegetation surveys, soil analyzes, grassland mineral analyzes, remote sensing, GIS, etc.), and at different spatial scales in order to identify the interrelationships between the different levels of vegetation organization and functions. Indeed, the emergence of "new ecosystems" requires managers to reconsider the initial principles of conservation management. Our study showed that, in the short term (3-5 years), grazing systems using herds of herbivores, whose organization is adapted to maintain open habitats, increase species richness, diversity and heterogeneity of plant communities compared to lack of management or mechanical interventions. Moreover, the annual species that appear are appetizing and contribute to increase the forage value of the site grazed by horses. These herbivores also have an impact on the permanent seed bank by increasing both its heterogeneity and the density of viable seeds under the most grazed patches. Grazing of cattle and horses confirm a correlation between the vegetation index (NDVI), biomass and plant species richness. Finally, we evaluated the efficacy of goats’ action on bramble via consumption indices calculated using GIS. Our different results are in the line with those already obtained in natural environments. Future experiments should test the effects of mixed grazing systems, particularly cattle, goats and horses, on the colonization dynamic of competitive shrubs such as brambles. Applied pastoral management should be considered in the medium term, via multi-year contracts to promote the sustainability of this management method and its effects over time
N'Guessan, Kouakou Edouard. "Utilisation des données satellitaires à haute résolution pour l'étude des ressources végétales en Côte d'Ivoire : cas des forêts classées de Badenou et du Haut Sassandra". Toulouse 3, 2004. http://www.theses.fr/2004TOU30006.
Texto completoFischer, Fabian. "Inférence de la structure et dynamique des forêts tropicales humides avec un modèle individu-centré". Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30229.
Texto completoClimate change presents society and science with a challenge that goes beyond the temporal and spatial scales of most practical problems. It therefore requires approaches that reflect the complexity of the Earth's system. This holds particularly true for the biosphere and forest ecosystems, one of the most important sources of uncertainty in climate projections. Concerted data collection efforts, such as forest inventories, trait data bases, and new technologies, such as remote sensing, have considerably increased our ability to observe and analyze the current state of the Earth's vegetation. However, to extrapolate findings into the future and understand the feedbacks between vegetation and climate change, models are needed that assimilate these data and translate them into ecosystem dynamics. Mechanistic and individual-based forest models are a particular promising approach, since they simulate dynamics bottom-up, reconstruct forests tree by tree, and are thus able to predict patterns across scales. This PhD further develops the trait- and individual-based forest growth simulator TROLL, including intraspecific variation and plasticity in tree growth, derives a new method to translate Airborne Lidar data into virtual forest inventories and uses it to infer forest structure and ecosystem dynamics in tropical rain forests. Finally, in line with TROLL's trait-based approach, an update to a global trait base, the Global Wood Density Database is presented, exploring the contribution of evolutionary lineages to wood density variation and mapping wood density across the globe
Fall, Ababacar. "Le Ferlo sénégalais : approche géographique de la vulnérabilité des anthroposystèmes sahéliens". Thesis, Paris 13, 2014. http://www.theses.fr/2014PA131028.
Texto completoThe pastoral anthroposystem of Senegalese Ferlo evolves in an environment historically neglected by agricultural policies because of its characteristics particular biophysics, unfavorable to the agriculture and to the shape of development other than the extensive breeding. This primacy of the itinerant breeding is nowadays more and more disputed by the development of the farming in a context marked by the improvement of the conditions of the rainfall in West-African Sahel, soil depletion in the Groundnut Basin and the multiplication of agricultural development at the valley of the Senegal River. By combining the analysis of remote sensing imagery for mapping land cover changes by the vegetation cover, the study of flora and vegetation landscape and the exploitation of the investigations in villages and camps, this thesis attempts to define the geography of the vulnerability of rural populations and ecosystems which they use. So, pastoralists evolve with daily adaptation strategies in these circles inside Senegal marked by deep ecological instability and by the transformations at work in the Senegalese rural society. These socio-environmental changes contribute to the dynamics of plant landscapes and raise the question of ecosystem degradation
Malounguidi, Mathurin. "Étude diachronique d'occupation du sol par photo-interprétation : interface urbain/rural, zone péri-urbaine de Brazzaville (R.P. Congo)". Toulouse 3, 1988. http://www.theses.fr/1988TOU30251.
Texto completoAllart, Théo. "Relation entre la configuration de l'habitat dans la végétation aquatique submergée et la distribution des poissons". Thèse, 2020. http://depot-e.uqtr.ca/id/eprint/9724/1/eprint9724.pdf.
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