Dissertations / Theses on the topic 'Modélisation de paysage'
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Houillon, Ismaël. "Modélisation du paysage agricole et inférence du risque pour l'accompagnement des réseaux d'épidémiosurveillance : application au paysage agrumicole réunionnais." Thesis, La Réunion, 2022. http://www.theses.fr/2022LARE0014.
Full textPlant disease surveillance is a major food safety issue. Although surveillance methods have been greatly improved in the last decade, especially with risk-based surveillance, implementing effective surveillance is not obvious in some regions. Reunion Island is an excellent example of such territories where organizing plant disease surveillance is a challenge due to its position as a DROM, with a very heterogeneous landscape and limited resources. Since 2012, Huanglongbing (HLB), caused by the bacterium Candidatus Liberibacter, is re-emerging in citrus orchards in Reunion Island and the state services have to organize the surveillance of a fragmented, heterogeneous citrus landscape and this taking into account local policies. We will show here the methods developed to improve the knowledge of the landscape, and thus better understand the potential epidemiological pathways. The approach of photo-interpretation of satellite images and field confirmation has allowed to consolidate the existing incomplete database. We will also show how risk-based surveillance can guide sampling. In the context of HLB surveillance in Reunion, a list of the most connected orchards was used to target sampling of areas most likely to be epidemiological nodes. We were able to show through learning algorithms that elevation and connectivity are variables of major importance in explaining the health status of citrus. Furthermore, the involvement of home gardens in the epidemic was highlighted, supporting the fact that the surveillance of the agricultural compartment alone was not sufficient. An evaluation of the surveillance system was also carried out using the OASIS method. This allowed us to highlight the good functioning of the core of the surveillance chain, despite the fact that positions in the central organization need to be defined and communication with the general public needs to be improved
Duretz, Sylvia. "Modélisation intégrée des flux et transformations d’azote à l’échelle du paysage." Paris 6, 2011. http://www.theses.fr/2011PA066081.
Full textPicard, Coralie. "Modélisation et optimisation de la gestion d’une épidémie : quel impact du paysage ?" Thesis, Montpellier, SupAgro, 2018. http://www.theses.fr/2018NSAM0026/document.
Full textHow to identify effective strategies to manage the epidemics impacting crops?The answer to this question is not obvious because of the complexity of epidemics (they simultaneously depend on biological processes, patch organization in the landscape, and human interventions). To answer that question, models can be used because of their ability to simulate many scenarios. Indeed, they can enable to estimate epidemiological parameters, to assess the efficiency of different management strategies and to optimize them.In this context, we developed a generic framework for in silico optimization of plant disease management strategies at the landscape scale. This framework is based on (i) the characterization of the epidemic dynamics to estimate its key parameters, (ii) the use of a spatially explicit model to simulate the dynamics and management of this disease and (iii) the use of numerical optimization methods to identify efficient management strategies. Here, we apply this approach to sharka, caused by Plum pox virus. This disease has a worldwide impact on the Prunus industry and is associated with huge management costs in many countries. In France, the management strategy for this disease principally consists of orchard surveillance, removal of trees that might contribute to the epidemic propagation, and plantation bans.My PhD indicates that some strategies should be more profitable than the one currently applied in France. These strategies require less orchard surveillance and do not impose any plantation ban. It turns out that some of these strategies are efficient for all tested landscape types, which may be interesting in practice for risk managers. This approach was applied to the sharka, but could be transposed to optimize the management of other epidemics
Depigny, Sylvain. "Le modèle PAYSAGRIExpérimentation de la sensibilité au paysage des agriculteurs comme facteur des évolutions du paysage rural." Phd thesis, AgroParisTech, 2007. http://tel.archives-ouvertes.fr/tel-00203110.
Full textsuggère l'hypothèse d'une sensibilité au paysage de l'agriculteur comme facteur de l'entretien des couverts végétaux des surfaces agricoles.
La parcelle agricole, unité élémentaire choisie du paysage, est définie par un État Fonctionnel Physionomique (EFP), qui renseigne l'agriculteur sur ses potentialités fourragères et paysagères. Chaque système de production agricole est à la fois associé à un objectif de
production et à une finalité paysagère, dictée par la sensibilité au paysage de l'agriculteur. Les pratiques de production courante, considérées optimales, modifient les EFP du parcellaire. Chaque année, les pratiques d'entretien permettent de corriger les physionomies des parcelles agricoles inadaptées aux attentes paysagères de l'agriculteur ; elles initient également une modification pluriannuelle de la conduite du système de production agricole, afin de répondre plus justement aux objectifs fixés.
Les simulations réalisées testent l'impact paysager de différentes populations d'agriculteurs sur un territoire virtuel comportant vingt exploitations agricoles. Chaque population représente une proportion donnée des deux types d'agriculteurs, respectivement deux sensibilités au paysage opposées. Les différences significatives observées soulignent la pertinence de considérer la
sensibilité au paysage des agriculteurs comme un facteur important de la modification des paysages ruraux.
Chiarello, Ernest. "Pyramide stochastique et écologie du paysage : modélisation des structures spatiales par images de synthèse." Lyon 1, 1994. http://www.theses.fr/1994LYO10078.
Full textGirardet, Xavier. "Paysage & [et] infrastructures de transport : modélisation des impacts des infrastructures sur les réseaux écologiques." Phd thesis, Université de Franche-Comté, 2013. http://tel.archives-ouvertes.fr/tel-01069242.
Full textSahraoui, Yohan. "Le paysage, entre esthétique & écologie : modélisation rétrospective à partir de changements d'occupation du sol." Thesis, Besançon, 2016. http://www.theses.fr/2016BESA1022/document.
Full textLandscape is both a backdrop to the lives of human populations and a medium for the life cycle of animal species. Landscape changes induced by land-use and land-cover dynamics affect both these dimensions, the one aesthetic, and the other ecological. Because these rationales areusually studied within different disciplines, little research has been done into how the two clashor combine as and when landscape structures change. This work seeks therefore to model the spatial co-evolution of the aesthetic and ecological functions of landscape retrospectively usingspatial metrics based on land-cover data. It focuses on changes in the urban fringes of two French cities (Paris and Besançon) over the last 30 years. The approach attempts first to use land-cover data to model (1) the landscape preferences of a set of individuals and (2) the ecological connectivity of a set of animal species. Drawing on both multivariate statistical analysis and spatial analysis, the core of this work consists in investigating how the two functions have evolved in convergent or divergent ways over time. The results provide fresh insight into the relationship between landscape aesthetics and landscape ecology and raise questions about the value of spatial modelling for a landscape management approach that endeavours to reconcile the preservation of residents’ living environments and the conservationof biodiversity
Soularue, Jean-Paul. "Évolution de la phénologie des arbres à l'échelle d'un paysage forestier." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14724/document.
Full textTiming of bud burst (TBB) is a key adaptive trait affected by temperature variations. Predicting the evolution of natural forests undergoing environmental variations requires to understand the evolutionary dynamics that have resulted in the strong patterns of differentiation characterized for this trait. It has been shown experimentally that the TBB was strongly correlated with the timing off lowering. This suggests that trees having similar TBB tend to mate preferentially, making assortative mating at TBB the default reproduction regime within tree species. Clinal patterns of genetic differentiation have been mostly interpreted as resulting from divergent selection, however, few studies have considered the peculiar features of timing of bud burst. Through a modelling approach based on quantitative genetics models, we first demonstrate here that the sole interaction between assortative mating at TBB and pollen flow can induce a clinal differentiation among populations without any selection pressure. In a such theoretical context, assortative mating filters pollen flow in presence of environmental gradients and progressively shifts the genetic values of populations. Then, we demonstrate that assortative mating amplifies the adaptive response of populations to co-gradient selection, and constrains it in the case of countergradient selection. Finally, we show that assortative mating differentiates populations even in the case of uniform selection
Bell, Michael. "Emission, dispersion et dépôt d'ammoniac de l'échelle de la parcelle à l’échelle du paysage." Thesis, Rennes, Agrocampus Ouest, 2017. http://www.theses.fr/2017NSARD083.
Full textEmissions of ammonia (NH3) to the atmosphere have been implicated in a web of harmful environmental impacts, from pollution of sensitive terrestrial and aquatic ecosystems to worsening of urban air quality. The application of atmospheric measurements and inverse dispersion modelling may be unique in providing a singular methodology which can quantify emissions of NH3 to the atmosphere from almost any source. However, there are various measurement and modelling techniques and options which may be implemented within the inverse dispersion method, which can be optimised for specific sources. The special case of NH3 in the context of inverse dispersion presents a number of measurement and modelling challenges, all related to the reactive nature of the molecule.This thesis features six experiments carried out in three countries, in which NH3 emissions were quantified from multiple sources across a broad range of scales and system complexities. In each case the inverse dispersion method was adapted to the specific nature of the source being investigated and the uncertainties of NH3 measurement and modelling, where local deposition must be considered. The experiments were undertaken with an emphasis on methodological evaluation, in which novel techniques were developed and alternative methods are compared.This thesis ultimately expands the scope of the inverse dispersion method applied for NH3 to the landscape scale, connecting with integrated nitrogen assessments which may bring forth new understanding into cascade of reactive nitrogen to the environment
Choucair, Ali. "Modélisation paysagère et urbanisation : une entrée de ville." Rouen, 1999. http://www.theses.fr/1999ROUEL318.
Full textFor the past thirty years, city access roads have been subjected to some disorganized development, as they have been object of anarchical implantation, mainly for commercial purposes, without any concern for proper planning. The aim of this doctorate dissertation is an attempt to clarify town planning and architectural solutions that are appropriate to the deteriorating peri-urban landscapes, in order to allow some discussion among the public before being implemented. This objective involves on the one hand a precise graphic restitution of the present situations, and, on the other hand, a panel of possible solutions. Visual tests must be proposed, in order to take benefits of the improvements linked to the reactions of the population concerned. There is therefore in this work an initial phase of analysis, a second phase of modeling, and a final phase of virtual 3d image restitution featuring different possible planning options. The present paper document is accompanied by a cd-rom containing the results of the modeling process, with "3d studio", a software for image processing : * the scene of the national road 14 (n14) from the borough of Boos to Rouen modeled using 3ds format (autodesk tm 3d studio). * the textures library including various types of buildings facades, vegetation, and road signs along the n14 that were scanned and treated using adobe Photoshop tm software. * the animations of three comparative planning options on the maxicoop commercial center at Bonsecours along the n14 road, using the avi format (audio-video interleaved). * a presentation of some modeled images in form of pictures along the road using the bmp format (windows-bitmap). * a general presentation of the thesis using the ppt format (microsoft powerpoint tm software)
Chaudy, Christophe. "Modélisation et rendu d'images réalistes de paysages naturels." Phd thesis, Université Joseph Fourier (Grenoble), 1997. http://tel.archives-ouvertes.fr/tel-00004925.
Full textBourhis, Yoann. "Dynamique de population et dépendance multi-échelle au paysage - modélisation mécaniste appliquée à la protection des cultures." Thesis, Rennes, Agrocampus Ouest, 2016. http://www.theses.fr/2016NSARA079/document.
Full textEnvironmental and health issues call for a switch in crop protection towards less chemically driven strategies. Pest damages on crops result of population dynamics that are influenced by landscape features. Those features may be relocated or dismissed to improve landscapes resistance to pest damages. Here we explore numerically the landscape modification as a crop protection strategy.Landscape features can influence population dynamics through their impact on individuals. Therefore, we developed a multiscale population dynamics model accounting for individual foraging. The foraging process results of (1) the perception of distant features used as resources by the individuals, (2) the localisation of the population along an additional dimension quantifying individual energy supply, (3) an optimisation procedure defining adapted directed motionsWe developed an evolutionary heuristic for landscape modification. It is able to rearrange landscapes with respect to compositional and structural constraints. Population and landscape models were applied to a theoretical landscape planning problem. The mechanistic description of the optimal foraging process enables new and efficient levers for crop protection, building on the disruption of the foraging behaviours. This application enlightens the responsiveness of the simulated population to landscape modifications, as well as the ability of evolutionary algorithms to produce resilient landscapes under agronomic productive constraints
Chaudy, Christophe. "Modélisation et rendu d'images réalistes de paysages naturels." Phd thesis, Grenoble 1, 1997. http://www.theses.fr/1997GRE10040.
Full textVannier, Clémence. "Observation et modélisation spatiale de pratiques agricoles territorialisées à partir de données de télédétection : application au paysage bocager." Phd thesis, Université Rennes 2, 2011. http://tel.archives-ouvertes.fr/tel-00651991.
Full textHouet, Thomas. "Occupation des sols et gestion de l'eau : modélisation prospective en paysage agricole fragmenté (Application au SAGE du Blavet)." Phd thesis, Université Rennes 2, 2006. http://tel.archives-ouvertes.fr/tel-00389835.
Full textL'objectif de ce travail est de produire une démarche méthodologique générique pour élaborer des scénarios prospectifs spatialisés. Fondée sur la méthode des scénarios en prospective, cette démarche se nourrit des apports méthodologiques utilisés en modélisation de systèmes complexes afin d'apporter une dimension spatiale aux scénarios prospectifs. Articulée avec le volet prospectif du SAGE du bassin versant du Blavet (2000 km²), cette démarche a été appliquée à trois petits sous bassins versants représentatifs de la diversité des paysages agricoles bocagers rencontrés. Elle s'organise en quatre phases. La première phase vise à construire « la base » des scénarios. La deuxième phase consiste à construire des scénarios prospectifs pertinents pour éclairer les futurs possibles du territoire étudié. La troisième phase constitue la phase de spatialisation des scénarios. Suivant le type de scénarios (exploratoire ou normatif), la méthode diffère : une plateforme de modélisation dynamique et spatialement explicite (L1) a été utilisée et optimisée dans le cas des scénarios exploratoires ; un SIG a servi pour élaborer les scénarios normatifs. Enfin, la dernière phase consiste à évaluer les scénarios prospectifs spatialisés, leurs impacts sur les ressources en eau et leurs apports pour les gestionnaires et les acteurs locaux.
Les scénarios exploratoires produits ont permis de quantifier et de localiser les influences possibles de la nouvelle réforme de la PAC appliquée en 2006, de l'agrandissement des exploitations agricoles sur l'évolution des modes d'usages des sols et également l'influence des changements de la structure spatiale du parcellaire sur les transferts de flux. Les scénarios normatifs ont permis d'identifier les enjeux de gestion de l'eau entre acteurs locaux et gestionnaires. Au final, la localisation de zones à risque vis-à-vis des ressources en eau et l'identification de leviers d'actions (synergies locales, maîtrise du foncier) confèrent aux scénarios prospectifs un rôle d'outil d'aide à la décision pour les gestionnaires de l'eau et les acteurs locaux.
Serrhini, Kamal. "Evaluation spatiale de la covisibilité d'un aménagement : sémiologie graphique expérimentale et modélisation quantitative." Tours, 2000. http://www.theses.fr/2000TOUR1801.
Full textCaillault, Sébastien. "Le feu, la brousse et la savane : Modélisation spatiale de la dynamique des paysages soudaniens (Burkina Faso)." Phd thesis, Université de Caen, 2011. http://tel.archives-ouvertes.fr/tel-00625721.
Full textDa, Silva Sébastien. "Fouille de données spatiales et modélisation de linéaires de paysages agricoles." Electronic Thesis or Diss., Université de Lorraine, 2014. http://docnum.univ-lorraine.fr/prive/DDOC_T_2014_0156_DA_SILVA.pdf.
Full textThis thesis is part of a partnership between INRA and INRIA in the field of knowledge extraction from spatial databases. The study focuses on the characterization and simulation of agricultural landscapes. More specifically, we focus on linears that structure the agricultural landscape, such as roads, irrigation ditches and hedgerows. Our goal is to model the spatial distribution of hedgerows because of their role in many ecological and environmental processes. We more specifically study how to characterize the spatial structure of hedgerows in two contrasting agricultural landscapes, one located in south-Eastern France (mainly composed of orchards) and the second in Brittany (western France, \emph{bocage}-Type). We determine if the spatial distribution of hedgerows is structured by the position of the more perennial linear landscape features, such as roads and ditches, or not. In such a case, we also detect the circumstances under which this spatial distribution is structured and the scale of these structures. The implementation of the process of Knowledge Discovery in Databases (KDD) is comprised of different preprocessing steps and data mining algorithms which combine mathematical and computational methods. The first part of the thesis focuses on the creation of a statistical spatial index, based on a geometric neighborhood concept and allowing the characterization of structures of hedgerows. Spatial index allows to describe the structures of hedgerows in the landscape. The results show that hedgerows depend on more permanent linear elements at short distances, and that their neighborhood is uniform beyond 150 meters. In addition different neighborhood structures have been identified depending on the orientation of hedgerows in the South-East of France but not in Brittany. The second part of the thesis explores the potential of coupling linearization methods with Markov methods. The linearization methods are based on the use of alternative Hilbert curves: Hilbert adaptive paths. The linearized spatial data thus constructed were then treated with Markov methods. These methods have the advantage of being able to serve both for the machine learning and for the generation of new data, for example in the context of the simulation of a landscape. The results show that the combination of these methods for learning and automatic generation of hedgerows captures some characteristics of the different study landscapes. The first simulations are encouraging despite the need for post-Processing. Finally, this work has enabled the creation of a spatial data mining method based on different tools that support all stages of a classic KDD, from the selection of data to the visualization of results. Furthermore, this method was constructed in such a way that it can also be used for data generation, a component necessary for the simulation of landscapes
Miguet, Paul. "Influence de l’hétérogénéité du paysage sur la distribution et la dynamique des populations." Thesis, Montpellier 2, 2013. http://www.theses.fr/2013MON20152.
Full textThe aim of this thesis is to understand how landscape heterogeneity (i.e. composition, configuration and temporal dynamics) affects populations, especially in farmlands, highly structured by the crop mosaic and rotations. We answer this question theoretically (simulating population dynamics in landscapes with controlled spatial and temporal properties) and empirically (analysing habitat selection by the farmland bird community).We found that landscape composition, configuration and temporal dynamics were all important to explain population dynamics and that the response to landscape heterogeneity depended on species traits (growth rate, dispersal, scale of response to the landscape). The analyse of farmland birds data revealed that crop composition influenced habitat selection for some species, but did not reveal a significant effect of crop configuration on birds. A finer analyse on Skylark showed a positive effect of crop diversity at the territory scale explained by a functional complementation among crops. It suggested that small fields and crop well mixed in the landscape would be beneficial for this species. The effect of spatial and temporal crop heterogeneity should be studied in depth at the right scale on many taxa. A good understanding of the effect of the cultivated matrix on processes would allow us to predict the change in populations when modifying the landscape and would offer new opportunities to manage biodiversity
Mancero, Baquerizo Daniel. "Composition musicale et modélisation de l'espace hétérophonique des Soundscape Compositions." Thesis, Paris 8, 2019. http://www.theses.fr/2019PA080041.
Full textThis work of thesis deals with the musical analysis and modelling of the particular sound events that structure and shape soundscapes. To this end, this work is organized around two complementary approaches: first, it seeks to assess the aesthetic and conceptual implications of acoustic ecology from a poietic perspective. This implies taking into account not only the theoretical principles underlying acoustic ecology, but also a set of criteria characterizing ways of listening from a phenomenological point of view. Secondly, this work introduces a specific dialogical methodology for identifying, describing and modelling the musical functionality of soundscape compositions, while fostering the deployment of other (rather syntactic) compositional techniques. Despite its wide acceptance as a mimetic approach to reconstitute soundscapes through field-recordings, one cannot fail to observe that, over the evolution of the repertoire of soundscape compositions, composers and acoustic designers have developed various compositional strategies that enable them to undertake larger and more sophisticated musical outlets. In this context, this work opens up new perspectives on music composition and musicological research: it is centered around the development of acoustical/musical analysis computer tools, as well as of methodologies supporting a dialogical process towards research and creation for better knowing about musical soundscape composition.On that basis, this work intends to contribute with a set of methodological and computational tools that will enable musicologists and composers to classify and represent the heterophonic field that characterizes the soundscape
Piombini, Arnaud. "Modélisation des choix d'itinéraires pédestres en milieu urbain : approche géographique et paysagère." Phd thesis, Université de Franche-Comté, 2006. http://tel.archives-ouvertes.fr/tel-00167224.
Full textCette recherche a pour objectif d'analyser les choix d'itinéraires pédestres en fonction des paysages urbains. Deux enquêtes sont pour cela mises en œuvre sur les sites de Lille et Besançon. La première a donné lieu au recensement de plus de 500 trajets en marche à pied ; la seconde a permis de qualifier précisément les paysages urbains. En mettant en œuvre plusieurs types d'analyses géographiques en partie inspirées des travaux des économistes et des psychologues, les caractéristiques des déplacements pédestres sont mises en évidence. Des modèles de choix discrets sont ainsi utilisés et le travail proposé conduit à élaborer une méthode originale d'évaluation des paysages urbains perçus par les piétons.
Devaux, Céline. "Modélisation et estimation de la dispersion efficace du pollen de colza à longue distance, dans un paysage agricole et dans un champ." Paris 11, 2006. http://www.theses.fr/2006PA112173.
Full textThis study aimed at building spatially explicit models of oilseed rape pollen dispersal to estimate dispersal kernels and conclude on the proportion of long-distance pollination. These dispersal kernels, that describe the probability of a pollen grain to fertilize a plant at a given distance, were estimated using data collected in a french production area (selommes, loir-et-cher) of 100 km² and containing 170 oilseed rape fields. First male-sterile plants were scattered in the study area to collect pollen grains. Then the genotypes of these pollen grains were retrieved using microsatellite markers. Dispersal kernels were estimated by maximising the likelihood of the genetic data under a mating model adapted to cultivated species. Results of this study showed that (1) sampled pollen clouds were diverse and differentiated, (2) these pollen clouds originated from close and distant fields (several hundred meters) and (3) half of the pollen clouds originated from pollen sources whose position and composition could not be precisely determined. The best-fitted dispersal kernel in this study (geometric) predicts much more long-distance pollination than the exponential functions that are commonly used and than dispersal kernels that were previously fitted within a field. The best-fitted kernel here was then (partially) validated by using it to predict cross-pollination rates observed in twelve canadian sites consisting of commercial fields of several hundred hectares
Gautier, Denis. "Analyse des rapports entre l'organisation spatiale et la gestion des ressources renouvelables appliquée aux paysages de châtaigneraie en Cévennes." Phd thesis, Université d'Avignon, 1996. http://tel.archives-ouvertes.fr/tel-00822584.
Full textDa, Silva Sébastien. "Fouille de données spatiales et modélisation de linéaires de paysages agricoles." Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0156/document.
Full textThis thesis is part of a partnership between INRA and INRIA in the field of knowledge extraction from spatial databases. The study focuses on the characterization and simulation of agricultural landscapes. More specifically, we focus on linears that structure the agricultural landscape, such as roads, irrigation ditches and hedgerows. Our goal is to model the spatial distribution of hedgerows because of their role in many ecological and environmental processes. We more specifically study how to characterize the spatial structure of hedgerows in two contrasting agricultural landscapes, one located in south-Eastern France (mainly composed of orchards) and the second in Brittany (western France, \emph{bocage}-Type). We determine if the spatial distribution of hedgerows is structured by the position of the more perennial linear landscape features, such as roads and ditches, or not. In such a case, we also detect the circumstances under which this spatial distribution is structured and the scale of these structures. The implementation of the process of Knowledge Discovery in Databases (KDD) is comprised of different preprocessing steps and data mining algorithms which combine mathematical and computational methods. The first part of the thesis focuses on the creation of a statistical spatial index, based on a geometric neighborhood concept and allowing the characterization of structures of hedgerows. Spatial index allows to describe the structures of hedgerows in the landscape. The results show that hedgerows depend on more permanent linear elements at short distances, and that their neighborhood is uniform beyond 150 meters. In addition different neighborhood structures have been identified depending on the orientation of hedgerows in the South-East of France but not in Brittany. The second part of the thesis explores the potential of coupling linearization methods with Markov methods. The linearization methods are based on the use of alternative Hilbert curves: Hilbert adaptive paths. The linearized spatial data thus constructed were then treated with Markov methods. These methods have the advantage of being able to serve both for the machine learning and for the generation of new data, for example in the context of the simulation of a landscape. The results show that the combination of these methods for learning and automatic generation of hedgerows captures some characteristics of the different study landscapes. The first simulations are encouraging despite the need for post-Processing. Finally, this work has enabled the creation of a spatial data mining method based on different tools that support all stages of a classic KDD, from the selection of data to the visualization of results. Furthermore, this method was constructed in such a way that it can also be used for data generation, a component necessary for the simulation of landscapes
Rosset, Nicolas. "Simulation rapide d'interactions vent-obstacle. Application à la modélisation de paysages désertiques et à la conception de voiture." Electronic Thesis or Diss., Université Côte d'Azur, 2024. http://www.theses.fr/2024COAZ4054.
Full textThe air being ubiquitous around us, it is a vital element to take into account to simulate natural phenomena, and design object immersed in this fluid. Depending on their size and nature, objects can be transported, deformed or slowed down by contact with air. In this way, wind erodes and shapes natural landscapes, and vehicles are designed to offer them less resistance. Studying these phenomena involves understanding and modeling wind-obstacle interactions. This is a challenging task, given the non-linear nature of the equations governing fluid flow. Accurately representing fluid behavior often requires the use of time-consuming solvers, which severely limits their use in certain contexts. In this thesis, we explore methods for efficiently describing these wind-obstacle influences in order to simulate them and anticipate their impacts in two use cases where the need for rapid results is crucial: Firstly, we focus on car design, proposing a tool to provide aerodynamic feedback to car designers on the shapes they propose. To enable rapid iterations on the design, this feedback on the flow behavior around the proposed shapes must be interactive. In a second step, we study different approaches to modeling desert landscapes, both simulating dunes and describing the patterns created by sand erosion/deposition around buildings. Here, the obstacle - the terrain - is constantly changing as sand is eroded and deposited by the wind. The wind must in turn be updated at each of these stages. These iterations require an appropriate method to avoid excessive computation times. We overcome these problems by proposing methods that seek the best compromise between computation time and accuracy of the phenomena at work in each case. We identify the necessary flow characteristics to limit the complexity of our algorithms, and present learning-based methods to speed up our algorithms. In the case of car design, we show how to train our aid system on instantaneous, synchronized observations, which are richer in information than averaged data. The neural model we obtain, combined with a learned parameterization of shapes, enables us to invert the problem formulation and propose optimized shapes to the designer. We assemble these tools and demonstrate their effectiveness in the case of 2D profiles.In the case of modeling desert landscapes, we note that saltation is the predominant mode of sand transport, which enables us to simplify our algorithm. Coupled with a fast wind simulation, we obtain an efficient method inspired by both natural sciences and computer graphics. We validate our approximations by comparing our results with real-world measurements.Finally, with a view to inverting the sand deposition algorithm for reverse infrastructure design, we describe preliminary results for accelerating air simulation by developing a self-learning formulation predicting averaged wind over a terrain. As this method is based on neural networks, it shows promise for inverse design
Adra, Walaa. "Influence des indicateurs paysagers et de leur échelle d'intégration sur l'habitat d'une espèce avienne : conséquences sur la modélisation de la qualité d'habitat de la Gélinotte dans une perspective de gestion conservatoire." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00858353.
Full textHouet, Thomas. "Occupation des sols et gestion de l'eau : modélisation prospective en paysage agricole fragmenté (Application au Schéma d'Aménagement et de Gestion des Eaux du Blavet)." Rennes 2, 2006. https://tel.archives-ouvertes.fr/tel-00389835.
Full textSince the new European water policy, water managers must restore a “good ecological state” of water resources for 2015. To be efficient and provide sustainability, water policies have to be implemented at a local scale (i. E. Hedgerow or field scale) but they must also adopt a long term vision, i. E. Considering possible future land use changes. The production of prospective scenarios of landcover and landscape feature changes may help water managers to realize more effective water policy controls. The aim of this work is to implement a generic methodology to build spatialized prospective scenarios. Its application is made on three watersheds representative of the Blavet landscape diversity (Brittany, France). The prospective scenarios made have localized at-risk areas towards water resources and identified stakeholders which contribute to consider spatialized prospective scenarios as powerful tools to help decision-makers to manage water resources efficiently and sustainability
Pierret, Pascal. "Activité agricole, organisation de l'espace rural et production de paysage : une démarche de modélisation multi-échelle testée dans le département de la Haute-Marne." Dijon, 1996. http://www.theses.fr/1996DIJOL033.
Full textLe, Ber Françoise. "Modélisation des connaissances et raisonnements pour l'analyse de paysages agraires à partir de données satellitaires." Nancy 1, 1993. http://www.theses.fr/1993NAN10342.
Full textBoncourt, Etienne. "Quantifier la perméabilité des domaines skiables pour la Grenouille rousse (Rana temporaria) : une approche combinant suivi GPS et génétique du paysage." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAV011/document.
Full textAnimal disperal is a key process for maintaining populations and metapopulations. In particular, amphibians move a lot during their life cycle made of seasonal migrations. This makes them sensitive to the structure of the landscape. Indeed, anthropogenic changes such as linear infrastructure can act as ecological barriers for animals and limit gene flow within the landscape. While the effects of roads and railways on animal movements have been widely studied, the effects of infrastructure related to winter sports activities such as ski slopes and lifts are less well known. Thus, the permeability of anthropized mountain environments is little known. This thesis aims to quantify the ecological permeability (or functional connectivity) of ski areas for a widely distributed mountain amphibian: the European common frog (Rana temporaria Linnaeus 1758). To do this, we combine individual movement tracking and landscape genetics studies to better understand the factors influencing frog movements and gene flow within the landscape. Individual tracking is carried out by means of GPS tags and step selection analysis. The landscape genetics study is carried out by gathering DNA samples from three ski areas in Savoie and a control area located in the Vanoise National Park. We tested the influence of several landscape variables related to topography (slope, altitude...), habitats (wetland network, land cover...) or human activities (presence of roads, ski slopes) on gene flow. By using a new method of resistance surface optimization, we show the importance of the wetland network for mountain amphibians. On the one hand, they serve as preferential habitat and, on the other hand, a dense network of wetlands ensures good landscape connectivity for the Common frog. We also highlight that the heterogeneity in effective population sizes in a landscape can distort the genetic distances measured between populations and we recommend the use of techniques to overcome such problems. Our work is important for the sustainable management of ski areas, the development of ski slopes or other recreational infrastructure that can be accompanied by the destruction of wetlands
Schaller, Noémie. "Modélisation des décisions d'assolement des agriculteurs et de l'organisation spatiale des cultures dans les territoires de polyculture-élevage." Phd thesis, AgroParisTech, 2011. http://pastel.archives-ouvertes.fr/pastel-00781098.
Full textSauter, Alain. "Evaluation du paysage et politiques publiques : application à l'agglomération de Montbéliard et à la commune de Morez (Franche-Comté)." Phd thesis, Université de Franche-Comté, 2011. http://tel.archives-ouvertes.fr/tel-00910153.
Full textMilia, Valentin. "Couplage de modèles de chimie quantique et d'algorithmes haute performance pour l'exploration globale du paysage énergétique de systèmes atomiques et moléculaires." Electronic Thesis or Diss., Université de Toulouse (2023-....), 2024. http://www.theses.fr/2024TLSEP095.
Full textThe primary aim of this thesis is to develop efficient methods for characterizing molecular conformations at a quantum level. Various methods devoted to the computation of molecular potential energy are reviewed, as well as the most popular potential energy surfaces (PES) global exploration schemes. In this context, a key contribution of this thesis is the coupling of the robotics-inspired Iterative Global exploration and LOcal Optimization (IGLOO) method, implemented in the MoMA software, with the quantum Density-Functional based Tight-Binding (DFTB) potential, implemented in the deMonNano software. The IGLOO algorithm integrates the motion planning Rapidly-exploring Random Trees (RRT) algorithm with local optimization and structural filtering. A proof of concept has been done through the identification of low-energy conformations of the alanine dipeptide.The IGLOO/DFTB coupling has been applied to the mapping of the PES of three close-sized molecules of the phthalate family (dibutyl phthalate DBP, benzyl butyl phthalate BBP and di-2-ethylhexyl phthalate DEHP), providing detailed insights into their different conformational landscapes. Various geometrical descriptors have been used to analyze their structure-energy relationships. Coulomb interactions, steric hindrance, and dispersive interactions have been found to drive the geometric properties and a strong correlation has been evidenced between the two dihedral angles describing the side-chains orientation of the phthalate molecules. The results demonstrate the method's capability to identify low-energy minima without prior knowledge of the PES.Furthermore, an innovative algorithm for the large-scale generation of molecular structures, including a conformational variety, is presented. It combines molecular graph generation with atom or fragment addition techniques. It is applied to provide an extensive database of 3D structures of hydrogenated amorphous carbon (a-CH) molecules. The analysis of the database generated in this study provides a comprehensive understanding of the relationship between the geometrical and electronic descriptors of a-C:H structures. These properties are compared with those of compact Polycyclic Aromatic Hydrocarbons and linear chains, representing limit cases.Finally, a review is given on methods aiming at identifying saddle points and transition paths between low-energy conformations on the PES. A first step toward the identification of transition paths between low-energy conformations using a motion planning algorithm, known as Transition-based Rapidly-exploring Random Trees (T-RRT), is presented. A similarity measure, designated as the Symmetrized Segment-Path Distance (SSPD), is used to compare the generated trajectories. Subsequently, a clustering technique, namely the Hierarchical Clustering Analysis (HCA), is employed to group similar trajectories in order to identify the common pathways, thereby providing valuable insights into the dynamics of conformational changes. The methodology has been successfully applied to the identification of low-energy paths between two minima of the alanine dipeptide PES.Overall, the research presents significant advancements in the exploration of complex molecular PES at a quantum level including (i) the IGLOO/DFTB coupling (ii) a novel algorithm for 3D structure generation of large-scale molecules and (iii) an original scheme allowing for the identification of multiple transition paths. Correlations between the structural, energetic and electronic properties have been evidenced for the polluting phthalate molecules and astrophysically relevant hydrogenated amorphous carbon (a-CH) molecules. These contributions pave the way for future research, aiming to extend these methods to larger and more complex systems
Boisteau, Benjamin. "Rôle de la structure du paysage dans la distribution spatiale et la régulation des colonies de reproduction du Héron cendré (Ardea cinerea) et modélisation de son expansion future." Rennes 1, 2006. http://www.theses.fr/2006REN1S037.
Full textRebaudo, François. "Modélisation de la dynamique spatio-temporelle d'insectes ravageurs des cultures dans des systèmes socio-écologiques." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2012. http://tel.archives-ouvertes.fr/tel-00836104.
Full textMoreau, Clémence. "Mettre en débat l’état de référence. Analyse des représentations des dynamiques paysagères au prisme des services écosystémiques." Thesis, Montpellier, 2019. http://oatao.univ-toulouse.fr/23867/1/Moreau_23867.pdf.
Full textLavorel, Sandra. "Structure spatiale, perturbations, et dynamique de la coexistence des espèces végétales : de l'expérimentation à la modélisation : l'exemple de friches méditerranéennes." Montpellier 2, 1991. http://www.theses.fr/1991MON20006.
Full textPéron, Guillaume. "Dynamique des populations : apport de la modélisation intégrée à l’échelle du paysage et de la prise en compte de l’hétérogénéité individuelle dans les modèles de capture-recapture." Montpellier 2, 2009. http://www.theses.fr/2009MON20076.
Full textBetween the local and the landscape scales (several connected populations), population dynamics can vary from one extreme to the other. During this thesis work I was interested in two methods that provide more insight into the local and regional dynamics of a population of black-headed gull Chroicocephalus ridibundus studied by capture-recapture of marked individuals. Integrated population models combine the information from population surveys at the landscape scale and information from capture-recapture data, in order to obtain precise estimates for the demographic parameters, in particular the transfer rates between different sites. This method made it possible to prove the effect of the colony size on demography: emigration of young individuals, age at first reproduction, and attraction of adults. This pattern indicates that intra-specific competition is non-negligible on the largest colonies. From then on, one could expect individual heterogeneity, due to competitive ability, which adds to the sex-biased dispersal effect. It is possible to accommodate this heterogeneity of multiple origin using multievent models, in order to obtain well-fitted models, which can be used as a basis for further hypothesis testing, and to simultaneously correct for the bias induced by individual heterogeneity. I worked on senescence, the decline in survival with age, with an application of multievent models and a comparative analysis across 72 species of birds and mammals
Messias, Pereira Nogueira Joana. "Apports de la télédétection globale pour la caractérisation et modélisation du régime des incendies au Brésil : vers une approche des patchs de feux." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT126.
Full textFires are intrinsic disturbances in ecosystems functioning, and affecting species distribution, biogeochemical cycles and biosphere/atmosphere interactions. The spatial and temporal pattern of burnt areas is mainly the consequence of a compromise between fuel biomass availability and its water status. Characterizing and modelling a fire regime then relies on a reliable spatial and temporal evaluation of mainly seasonality and intensity of drought. In fire-prone ecosystems as savannas, the most fire affected biome globally, the only available information on burnt areas are derived from global remote sensing. Despite this information has been widely used for a global assessment of carbon emissions from fires since 2000, uncertainties remain important among data sources available for the scientific community. As well, processes used in the dynamic modelling of burned areas, embedded in vegetation models, are based on empirical equations quantifying the seasonal pattern of drought. For ecosystems like Brazilian savannas where fire information only rely on global remote sensing products, and where the variability in vegetation functional types affects the soil water budget, evaluating uncertainties on these variables is a prerequisite for an adequate modelling of processes. This thesis then aimed at characterizing the fire seasonality and the associated uncertainties in the different Brazilian biomes based on the main sources of global burned area (GFED4, GFED4s, MODIS MCD45A1, ESA FIRECCI) and a panel of drought indices developed by forest services worldwide. This thesis also investigated the same relationships analysis but with burned areas derived from the major dynamic global vegetation models (DGVM) coupled with fire modules, in order to test whether the burned area/drought relationships based on remote sensing are conserved in global models. After a review of the main processes computed in DGVMs, and particularly the new developments on the characterization of fire patches, the second part of this research aimed at evaluating the ability of global remote sensing products at 500m resolution to conserve patch morphologies captured at finer resolutions, for better characterizing fire regimes and evaluate DGVMs performances. The last part of this work used a functional biogeography approach based on fire morphological traits to describe an assemblage of fire events and to compare them between different remote sensing products, in order to evaluate their similarities and discrepancies, or between biomes for a new approach of comparative pyrogeography
Villanueva, Villa Antonio. "Services écosystémiques et paysage : Interactions dans un système socio-écologique à la périphérie de la Ville de Mexico." Thesis, Paris, Institut agronomique, vétérinaire et forestier de France, 2018. http://www.theses.fr/2018IAVF0020.
Full textIn an era dominated by strong anthropogenic transformations, the search for new approaches to reconcile human activities and natural ecosystems is becoming increasingly important. In this sense, the concepts of "Ecosystem Services" and "Socio-Ecological Systems" are increasingly used in different scientific disciplines and are taken into account in political spheres to draw attention to the benefits that humans derive from ecosystems. These concepts lead to the study of complex links between society and nature, where the spatial dimension and landscape characteristics have a strong influence. However, few studies have been applied in a spatial approach.This thesis presents a research on the spatial dimension of Ecosystem Services, in particulary those of the temperate forests of the mountains on the periphery of Mexico City. Ecosystems have an important role to the human well-being through many ecosystem services. These Ecosystem Services are the result of complex interactions between nature and society.The Central Valley (central zone) of Mexico is a priority area for biodiversity conservation due to the high degree of endemism of the fauna and flora species present. In this zone where several protected natural areas are located, a public-private initiative is seeking to create a new conservation category that includes the management of all these areas. This initiative is known as the "Bosque de Agua" (Water Forest). However, in the "Bosque de Agua" the spatial stakes between nature and society are subject to strong anthropic pressures which are due to mining and agricultural activities and to the urban spread of large conurbations. In this space, these pressures lead to the degradation of natural ecosystems. Research is needed to analyse the spatial dimension of interactions between nature and society, by studying the synergy between Socio-Ecological Systems and Ecosystem Services.The thesis introduces the conceptual framework used to study the links between Ecosystem Services and Socio-Ecological Systems. It is considered in this research that Ecosystem Services are at the centre of the "Bosque de Agua" Socio-Ecological Ecological System.In the spatial modelling section, four Ecosystem Services were evaluated (water supply, wood supply, food supply and local climate regulation).The results of this section include a map of Ecosystem Services by identifying hotspots of Ecosystem Services. These results make explicit in space, through geographically weighted regressions, the impact of landscape characteristics on Ecosystem Services.In addition, the spatial coherence of protected natural areas and the spatial distribution of Ecosystem Services were assessed in terms of area. The objective is to create a typology of natural areas according to the surface area of protected and unprotected Ecosystem Services hotspots.Finally, a third result relates to the perception of local inhabitants of the intrinsic capacity of the "Bosque de Agua" to provide Ecosystem Services. This perceived capacity was assessed through field photo questionnaires
Pace, Benoit. "Organisation et usages des espaces en Aquitaine méridionale durant la période romaine (Ier s. a.C. - Ve s. p.C.)." Thesis, Pau, 2020. http://www.theses.fr/2020PAUU1087.
Full textIs research had been defined as an interrogation about the way that mountain spaces, piedmont and plain of southem aquitaine were structured,lay out and used during roman period between end of 1st Century BC and the first hait of 5th entury AD. Positioned at the intersection between Arohaeology and Geomalics (statistical analysis of data, spatial modelling, development and use of GIS) this thesis is based on a diachronie collective research project between the Garonne nd Ebro rivera (POEM - project financed by the Pau and Pyrenees Agglomeration Community (C.DA.P.P.),under the direction of Fr. Réchin).The core of this thesis is the analysis of ancientsetuementsystems and dynamics between the Garonne and the Pyranees.lt s based on the elaboration of an original conceptual data model (CDM)allowing to circumscribe the main factors composing is system and thus takes into account a set of complementary data including all the layers of habitats (urban and rural) vailable; the main artisanal activities;the communication networks as well as the forms of the sacred (religious andfunerary).The problematie developed inthis thesis therefore relate as much to the distribution of settlements as to their setllement trategy induced by their relationship with the environment (hydrographie,topographie,pedological,etc.),or to their creation nd abandonmentdynamics,their functional characterization and their formation into a coherent settlement network in the long term
Cordonnier, Guillaume. "Modèles à couches pour simuler l'évolution de paysages à grande échelle." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAM072/document.
Full textThe development of new technologies allows the interactive visualization of virtual worlds showing an increasing amount of details and spacial extent. The production of plausible landscapes within these worlds becomes a major challenge, not only because the important part that terrain features and ecosystems play in the quality and realism of 3D sceneries, but also from the editing complexity of large landforms at mountain range scales. Interactive authoring is often achieved by coupling editing techniques with computationally and time demanding numerical simulation, whose calibration is harder as the number of non-intuitive parameters increases.This thesis explores new methods for the simulation of large-scale landscapes. Our goal is to improve both the control and the realism of the synthetic scenes. Our strategy to increase the plausibility consist on building our methods on physically and geomorphologically-inspired laws: we develop new solving schemes, which, combined with intuitive control tools, improve user experience.By observing phenomena triggered by compression areas within the Earth's crust, we propose a method for the intuitive control of the uplift based on a metaphor on the sculpting of the tectonic plates. Combined with new efficient methods for fluvial and glacial erosion, this allows for the fast sculpting of large mountain ranges. In order to visualize the resulting landscapes withing human sight, we demonstrate the need of combining the simulation of various phenomena with different time spans, and we propose a stochastic simulation technique to solve this complex cohabitation. This methodology is applied to the simulation of geological processes such as erosion interleaved with ecosystems formation. This method is then implemented on the GPU, combining long term effects (snow fall, phase changes of water) with highly dynamics ones (avalanches, skiers impact).Our methods allow the simulation of the evolution of large scale, visually plausible landscapes, while accounting for user control. These results were validated by user studies as well as comparisons with data obtained from real landscapes
Morel, Charlene. "Des Hommes et des Lœss : modélisation des stratégies d’implantation agricole en Europe tempérée du Néolithique au Moyen âge." Electronic Thesis or Diss., Strasbourg, 2023. http://www.theses.fr/2023STRAG036.
Full textThis thesis’ guiding questions were “did the communities from the Neolithic to the Middle Ages choose strategically where to settle in the loessic landscapes?” and “how can we prove that such strategies existed?”. To answer them, we chose three areas within the European loess belt: Sussex (UK), the Kochersberg plateau (Alsace, France) and the Kladno district (Bohemia, Czech Republic). Then, we built a spatial geoarchaeological modelling to consider both the archaeological biases (post-depositional sedimentary process and state of archaeological research) and the potential attractivity of a given area regarding the fertility and the nearest watercourse. Pooling these parameters together offers a result that we propose to interpret both geographically and statically to answer our main problematics
Dumrongrojwatthana, Pongchai. "Interactions entre élevage bovin et reboisement dans le socio-écosystème des hautes terres de la province de Nan au Nord de la Thaïlande : un processus de modélisation d'accompagnement pour améliorer la gestion du paysage." Thesis, Paris 10, 2010. http://www.theses.fr/2010PA100064/document.
Full textThe expansion of protected and reforestation areas in the head watersheds of northern Thailand, a region severely affected by deforestation during the past decades, is forcing the local farms to adapt rapidly and is at the origin of frequent land use conflicts between farmers and foresters. If the former state that cattle grazing is having a positive effect on forest regeneration, the latter disagree. Based on an interdisciplinary and multi-scale diagnostic analysis, the thesis presents the conception and implementation of a companion modelling (ComMod) process, involving different types of Hmong herders and two government forest agencies, that was designed to mediate such a local land use conflict in Nan province. Three successive sequences of collaborative modelling and simulation activities relying on as many versions of a computer-assisted role-playing game adapted to the evolution of the participants focus of interest were implemented to (i) improve communication, knowledge exchange, and trust between herders and foresters, (ii) simulate the introduction of artificial pastures in the local forest – farm land interface, in association or not with the rotation and collective management of the herds, and (iii) introduce the herders to the use of simulations to explore possible future land use scenarios in their village. Following this collaborative modelling and knowledge integration process, an autonomous agent-based model was built and used to explore, in the laboratory at this stage, several scenarios proposed by the local stakeholders regarding the evolution of livestock rearing practices facing reforestation efforts and the establishment of a new national park. We show how the ComMod process was able to reconcile the two conflicting parties and facilitated the joint adoption of a common action plan relying on an experiment to assess the management of Bracharia ruziziensis pastures under highland environmental conditions. The analysis of interactions between the different types of participants and sources of knowledge involved in this modelling process leads to the proposition of several follow-up activities. One consists in out-scaling this kind of learning by simulating exercises with other communities facing similar land use conflicts, and another deals with the use of the family of models co-constructed with the local stakeholders in teaching and training future renewable resource managers in rural areas
Bellot, Benoit. "Améliorer les connaissances sur les processus écologiques régissant les dynamiques de populations d'auxiliaires de culture : modélisation couplant paysages et populations pour l'aide à l'échantillonnage biologique dans l'espace et le temps." Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1B008/document.
Full textA promising alternative to the chemical control of pests consists in favoring their natural enemies populations by managing the agricultural landscape structure. Identifying favorable spatio-temporal structures can be performed through the exploration of landscape scenarios using coupled models of landscapes and population dynamics. In this approach, population dynamics are simulated on virtual landscapes with controlled properties, and the observation of population patterns allows for the identification of favorable structures. Population modeling however relies on a good knowledge about the ecological processes and their variability within the landscape elements. Current state of knowledge about the ecological mechanisms underlying natural enemies’ of the carabid family population dynamics remains a major obstacle to in silico investigation of favorable landscape scenarios. Literature about the relationship between carabid population and landscape properties allows the formulation of competing hypotheses about these processes. Reducing the number of these hypotheses by analyzing the convergence between their associated population patterns and investigating the stability of their convergence along a landscape gradient appears to be a necessary tep towards a better knowledge about ecological processes. In a first step, we propose a heuristic method based on the simulation of reaction-diffusion models carrying these competing hypotheses. Comparing the population patterns allowed to set a model typology according to their response to the landscape variable, through a classification algorithm, thus reducing the initial number of competing hypotheses. The selection of the most likely hypothesis from this irreducible set must rely on the observation of population patterns on the field. This implies that population patterns are described with spatial and temporal resolutions that are fine enough to select a unique hypothesis among the ones in competition. In the second part, we propose a heuristic method that allows determining a priori sampling strategies that maximize the robustness of ecological hypotheses selection. The simulation of reaction-diffusion models carrying the ecological hypotheses allows to generate virtual population data in space and time. These data are then sampled using strategies differing in the total effort, number of sampling locations, dates and landscape replicates. Population patterns are described from these samples. The sampling strategies are assessed through a classification algorithm that classifies the models according to the associated patterns. The analysis of classification performances, i.e. the ability of the algorithm to discriminate the ecological processes, allows the selection of optimal sampling designs. We also show that the way the sampling effort is distributed between its spatial and temporal components is strongly impacting the ecological processes inference. Reducing the number of competing ecological hypotheses, along with the selection of sampling strategies for optimal model inference both meet a strong need in the process of knowledge improvement about the ecological processes for the exploration of landscape scenarios favoring ecosystem services. In the last chapter, we discuss the implications and future prospects of our work
Li, Zhichao. "Modélisation des relations entre occupation - usage du sol et distribution spatiale du paludisme par télédétection optique et radar : application à un environnement en évolution : région transfrontalière Guyane Française – Brésil." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT144/document.
Full textMalaria remains one of the most common vector-borne diseases what is predominantly located in the tropics. The study area is the cross-border area between French Guiana and Brazil where the level and intra-annuel dynamic of malaria transmission are variable, with the incidence rates which are relatively high in South America. The environmental risk factors, in particular, land use and land cover, significantly influence the presence, density and spatial distribution of disease vectors, Anopheles mosquitoes. Environmental information, population data and health systems database are rarely comparable on both sides of the Guyana-Brazil border which exclude the homogeneous and bilateral vision. Remote sensing permits to spatially characterize the environment on both sides of the border in an almost continuous and complete manner. The objective of this study is to characterize the favorable environment for the development of vectors and the vector-human interaction in the cross-border area between French Guiana and Brazil using remote sensing. A spatial landscape-based hazard index of malaria transmission was developed at the local scale. Such index allows spatializing the contribution of interaction between forest and non-forest areas on malaria transmission which was then implemented in the entire Amazon region. It quantifies and explains the influence of landscape on the interaction between human population and adult vectors. The identification of potential breeding sites of vectors was tested on a regional scale using the optical and SAR fusion for highlighting the spatial distribution of perennial and large wetlands (lakes, rivers, ponds etc.) and the interfaces with urban and forest environments. The distribution of vectors’ density is affected by physical and chemical properties of potential breeding sites which are related to soil typology. A conceptual model of soil evolution adapted to the Amazon region presents that geomorphological characteristics (altitude, curvature, etc.) are indicators of soil evolution. A soil classification was realized at the regional scale using altimetry data and the conceptual model. The methods, land use and land cover and malaria hazard maps established in this thesis will be integrated in the Observatory Sentinel of cross-border which is being built. This study also contributes to the exploitation of new knowledge about malaria transmission mechanism which can be used to define novel prevention strategies at the local and regional scales
Agbanou, Bidossèssi Thierry. "Dynamique de l'occupation du sol dans le secteur Natitingou-Boukombé (nord-ouest bénin) : de l'analyse diachronique à une modélisation prospective." Thesis, Toulouse 2, 2018. http://www.theses.fr/2018TOU20076.
Full textIn Benin, forests and savannahs are the predominant types of land use and constitute dynamic systems whose evolution depends on several environmental and anthropogenic factors. In the Natitingou-Boukombé sector (Northwestern Benin), most of these ecosystems are in degradation due to increased anthropogenic activities. The objective of this study is to quantify the landscape dynamics and explore all possible future land use using remote sensing tools. The data used are mainly Landsat TM satellite images from 1987, ETM+ from 2000, OLIR TIRS from 2016, Modis VCF and NDVI series from 2000 to 2016. A multi-date classification was used to quantify land use changes in this study area.The results show that between 1987 and 2016, the landscape initially dominated by clear forests and wooded savannahs (38.81%) and wooded savannahs and shrubs (25.82%) in 1987 was replaced by land use categories, the most important of which were wooded savannahs and shrubs (40.53%) and cropland and fallow mosaics (50.61%) in 2016. Human activities and climatic disturbances are the main determinants of this land use dynamics. These explanatory factors, combined with the prospective analysis, made it possible to explore three possible future-oriented scenarios by 2031.The Business-As-Usual scenario (BAU) extrapolating current trends shows that by 2031 the landscape of this study area will be dominated by mosaics of crops and fallow land (69.64%), tree and shrub savannahs (21.93%), saxicultural savannahs (3.6%) and agglomerations (2.66%). In the Rapid Economic Growth (REC) scenario, which focuses solely on increasing agricultural production, the landscape will consist mainly of mosaics of crops and fallow land (73.72%), wooded savannahs and shrubs (17.35%), saxicultural savannahs (3.7%) and agglomerations (3.06%). The Coordinated Environmental Sustainability (CED) scenario, which incorporates environmental preservation, presents a landscape essentially composed of mosaics of crops and fallows (67.97%), wooded savannahs and shrubs (22.6%), saxicultural savannahs (3.7%), agglomerations (2.3%), clear forests and wooded savannahs (1.7%) and plantations (1.05%). In the latter scenario, there is therefore an effort to restore wooded savannahs and shrubs, clear forests and wooded savannahs and plantations.This landscape, on which the survival of populations depends, is evolving in the sense of its degradation. And it will get worse by 2031 if nothing is done. But the results obtained in the Coordinated Environmental Sustainability (CED) scenario show that hope is possible if the authorities in charge of land management and the environment integrate the stolen environmental preservation into their decision-making
Collard, Blanche. "Effet de l’organisation spatiale intra-parcellaire des habitats sur le contrôle biologique par conservation : étude et modélisation des déplacements de dermaptères dans les bananeraies Spatial organisation of habitats in agricultural plots affects per-capita predator effect on conservation biological control: an individual based modelling study." Thesis, Avignon, 2019. http://www.theses.fr/2019AVIG0710.
Full textIn this thesis, we investigated whether - and how - the intra-plot spatial patterns of habitats favourable to generalist predators could influence the conservation biological control (CBC) through their foraging behaviour. The general approach of this work is based on a modelling approach guided by experiments on the earwig E. caraibea, a generalist predator in banana fields of Martinique. In an experiment in banana fields, we found that the abundance and activity of earwigs seemed to be influenced by habitat types: banana tree residues appeared to be particularly more favourable to earwigs than bare soil.We developed a spatially explicit and individual-based model (Foragescape) of the foraging movements of an earwig-like predator in a banana field - based on the favourable or unfavourable nature of habitats. We found that the per-capita predator effect was strongly affected by a spatial dilution of predators, induced by favourable habitat addition, but this negative effect could be partially or fully mitigated by their spatial organisation.A key hypothesis of the Foragescape model was found on earwigs in a mesocosm experiment: earwigs movements are slower and more sinuous on residues, a favourable habitat, than on bare soil, an unfavourable habitat. Therefore, the model's predictions on spatial organisation and CBC can to some extent be adapted to the earwigs in banana fields
Jeandet, Louise. "Modélisation numérique des liens entre séismes et glissements de terrain au cours du cycle sismique : processus déclencheurs, distributions de tailles et implications géologiques." Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1B063/document.
Full textInteractions between tectonic processes and erosion have been poorly investigated at short time-scales (<1000 years). However, earthquakes can largely contribute to the erosion of mountain belts by triggering widespread landsliding. Moreover, recent studies have shown that such large erosional events could induce stress changes in the fault environment efficient enough to influence regional seismicity. In this thesis, this problematic is tackled through a numerical approach. Firstly, the development of a simple mechanical model accounting for the complexity and variability of natural hillslopes allowed to demonstrate the role of mechanical parameters (cohesion and friction), and of hillslope shape in the probability density function of landslide sizes. This model has been validated using natural cases of co-seismic landsliding. Secondly, the role of unstable hillslope height on large landslide probability has been demonstrated based on natural data, and the exponential distribution of this unstable height has ben shown. Finally, the potential effect of a large erosional event on seismicity has been explored with a numerical model of seismic cycle, in which has been implemented temporal normal stress variations. The results emphasize the role of eroded sediment volume, but also of the export time of sediments away from the mountain belt. In landscape with high unstable hillslopes, large landslides are favored and in turn, could induce fast an important enough erosion to modify regional seismicity
Mama, Adi. "Anthropisation des paysages au Bénin: dynamique, fragmentation et développement agricole." Doctoral thesis, Universite Libre de Bruxelles, 2013. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209532.
Full textAfin de mieux comprendre l’anthropisation des paysages au Bénin, la dynamique de l’occupation du
sol a été évaluée en zone soudanienne (Nord-Bénin), soudano-guinéenne (Centre-Bénin) et guinéenne (Sud-Bénin) à partir de trois images satellitaires de type Landsat MSS 1972, TM 1986 et ETM+ 2006.
Ces trois zones reflètent assez bien le contexte environnemental et humain de la zone intertropicale.
L’objectif principal de la présente thèse est de quantifier la dynamique paysagère due à l’anthropisation des paysages de forêts-savanes à partir de la télédétection, du système d’information géographique et de l’écologie du paysage.
Nos résultats ont montré que l’équilibre écologique des paysages de forêts-savanes a subi
d’importantes perturbations. L’agriculture itinérante sur brûlis, l’exploitation forestière, la carbonisation, l’urbanisation, les feux de végétation et les plantations ont été identifiés comme les principales forces motrices de ces dynamiques. Les matrices paysagères, qui étaient historiquement constituées de forêts-savanes ont été remplacées par une mosaïque de savanes, de champs-jachères, de sols nus-agglomérations, des plantations forestières et fruitières. L’exploitation des données de télédétection a permis de distinguer 4 grands processus de transformation spatiale des classes d’occupation du sol.
Ainsi, entre 1972 et 2006, les processus dominants dans le paysage ont été la déforestation, la savanisation, le développement agricole marqué par la création suivie de l’agrandissement des taches de champs-jachères.
La quantification des perturbations anthropiques, des indices de la structure spatiale calculés pour
chaque classe d’occupation du sol sur la base de la densité, de l’aire moyenne, de la dominance, de
l’indice de forme et la dimension fractale des taches des classes a permis de détecter un processus global de fragmentation et d’anthropisation des paysages.
Les dynamiques temporelles de la structure et de la composition des paysages de forêts-savanes dans
les 3 zones climatiques du Bénin ont montré une anthropisation illustrée surtout par la fragmentation des forêts-savanes. La simulation des dynamiques à l’horizon 2025 à partir de la chaine de Markov de premier degré a montré que pendant que les champs-jachères, plantations et les sols nus-agglomération s’étendront, les forêts-savanes connaîtrons une forte diminution. En définitive, notre étude a mis en évidence que toutes les trois zones étaient fortement dynamiques. Ces transformations anthropiques vont compromettre dangereusement l’avenir de ces paysages dont dépend la survie des populations locales. Notre approche permet de poser les bases d’une politique rationnelle de conservation et d’aménagement des paysages naturelles en établissant des seuils structuraux minimaux des fragments nécessaires à la préservation de la biodiversité.
Abstract
To understand better the landscape anthropization in Benin, the dynamics of the land use was
estimated in soudanian zone (North-Benin), soudano-Guinean (Centre-Benin) and guinean (south-
Benin) from 3 Landscape satellite images (MSS 1972, TM 1986, and ETM+ 2006), supported by field
visits. These 3 zones reflect well enough the environmental and human context of the intertropical zone. The main objective of the present dissertation was to quantify the landscape dynamics due to the landscapes anthropization of forests-savannahs from the Remote Sensing, Geographic Information System and from Landscape Ecology.
Our results showed that the ecological balance of the forests-savannahs underwent important
disturbances. Slash-and-burn agriculture, logging for timber, carbonization, urbanization, vegetation fire and tree plantations have been identified as the main driving strengths of these dynamics.
The landscape matrix’s, which were historically constituted by forests-savannah, has been substituted by a mosaic of savannah, fields-fallows, grounds nudes-urban area and plantations. The use of Remote Sensing data allowed distinguishing four big spatial transformation processes of the land cover classes.
So, between 1972 and 2006, the dominant processes in the landscape were the deforestation, the
savanization, the agricultural development marked by the creation followed by the enlargement of the
spots of field-fallows. The anthropogical disturbances quantification of the spatial structure indications calculated for every land cover classes on the basis of the density, average area, dominance, shape index and the fractal dimension index of the patches classes allowed detecting a global fragmentation
process and the anthropization of the landscapes.
The temporal dynamics of the structure and composition of the forests-savannahs landscape in the 3 climatic zones area of Benin showed an anthropization illustrated especially by the forest-savannahs fragmentation. The dynamics simulation by 2025 referring to Markov chains of the first degree tendency showed that while fields-fallows, tree plantations and nudes-urban area will extend, forestssavannahs shall know a strong decrease.
After all, our study highlighted that every 3 zones were highly disturbed. These anthropogenic
transformations are dangerously going to compromise the future of these landscapes on which depends the local populations survival.
Our approach allows putting the bases of a rational preservation policy and management natural landscapes by the thresholds establishment of fragments necessary for the biodiversity conservation.
Doctorat en Sciences agronomiques et ingénierie biologique
info:eu-repo/semantics/nonPublished