Dissertationen zum Thema „Écologie – Résilience“
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Laurence, Edward. „La résilience des réseaux complexes“. Doctoral thesis, Université Laval, 2020. http://hdl.handle.net/20.500.11794/66989.
Der volle Inhalt der QuelleReal complex systems are often driven by external perturbations toward irreversible transitions of their dynamical state. With the rise of the human footprint on ecosystems, these perturbations will likely become more persistent so that characterizing resilience of complex systems has become a major issue of the 21st century. This thesis focuses on complex systems that exhibit networked interactions where the components present dynamical states. Studying the resilience of these networks demands depicting their dynamical portraits which may feature thousands of dimensions. In this thesis, three contrasting methods are introduced for studying the dynamical properties as a function of the network structure. Apart from the methods themselves, the originality of the thesis lies in the wide vision of resilience analysis, opening with model-based approaches and concluding with data-driven tools. We begin by developing an exact solution to binary cascades on networks (forest fire type) and follow with an optimized algorithm. Because its practical range is restricted to small networks, this method highlights the limitations of using model-based and highly dimensional tools. Wethen introduce a dimension reduction method to predict dynamical bifurcations of networked systems. This contribution builds up on theoretical foundations and expands possible applications of existing frameworks. Finally, we examine the task of extracting the structural causesof perturbations using machine learning. The validity of the developed tool is supported by an extended numerical analysis of spreading, population, and neural dynamics. The results indicate that subtle dynamical anomalies may suffice to infer the causes of perturbations. It also shows the leading role that machine learning may have to play in the future of resilience of real complex systems.
Dardonville, Manon. „Caractérisation des formes d’agriculture et évaluation de leur résilience aux perturbations“. Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0123.
Der volle Inhalt der QuelleIn response to the issues of environmental impact and dependence on fossil resources of modern agriculture, new agriculture models have emerged: regenerative, integrated agriculture, agroforestry, for example. They aim to use ecosystem services provided to farmer (ESF) as a support for agricultural production to replace anthropogenic inputs. Their resilience to climate change and economic market fluctuations, i.e. their capacity to cope with these disturbances, is the subject of intense debate. Yet, knowledge of their resilience would be key to accelerating their adoption by the agricultural community and achieving sustainability goals. In response to this challenge, my PhD thesis aimed to produce knowledge on the resilience of different agriculture cropping models. To achieve this objective, first, I synthesized the literature on the quantitative assessment of resilience, and related concepts such as vulnerability and robustness (V, R, R). A first publication shows that intensification and diversification of production are not systematic factors of VRR and that it is necessary to consider functional, rather than taxonomic, diversity and to adapt agricultural practices, to the pedoclimate and to the availability of local resources, to ensure VRR in the short and long term. A second publication describes the diversity of methods and criteria for analyzing the dynamics used so far and points out the need to develop multi-criteria and multi-performance approaches that go beyond yield analysis alone. Then, I developed and applied a method for assessing the level of ESF to characterize agroecosystems and identify agriculture models. ESF levels were differentiated according to the potential capacity of ESF, the real capacity of ESF, the actual use of ESF for production, and the long-term dynamics of natural capital, which underlies ESF. The potential and real levels of ESF are assessed indirectly with indicators of the quality of the spatial and temporal configuration of the agroecosystem and the impact of cropping practices. The level of ESF used is estimated by the technology implemented to assess ESF real capacity. The dynamics of natural capital is estimated by the aggregation of indicators of erosion sensitivity, soil carbon and phosphorus dynamics and biodiversity. Applied to a case study in Grand Est region in France of 34 agroecosystems contrasted in terms of crop rotation and cropping practices, I identified with a clustering method five agriculture models. Finally, I developed a method to assess the resilience of these agroecosystems and associated agriculture models in the face of disturbances. I analyzed the dynamics of the yield, gross margin and workload considering their average level, variability, trend and/or resistance over the last eight years. I thus showed that models with a high level of ESF and biodiversity, and which increase their natural capital, present a better stability of yield and gross margin but a generally lower level of production. In contrast, intensive systems have higher levels and greater resistance of yields and gross margins but require a greater amount of labor. I have also observed that the systems that use ESF the most have good agronomic and economic performances, resistant to disturbances. Thus, I hypothesize that the combination of a high level of ESF and the optimization of their use would avoid the use of inputs while achieving high, resistant yields. However, to achieve this goal, it would be necessary to increase the levels of potential and used ESF, which are still insufficient in the agroecosystems studied.In summary, this work has produced knowledge on the nature of agriculture models and resilience factors and original methods to assess the levels of ESF and their resilience. Its results show the interest, with a view to resilience, of developing and mobilizing ESF and alert on the importance of restoring natural capital, often degraded by decades of intensive agriculture
Stathopoulos, Marco. „La résilience urbaine : art de la crise et architectures pirates“. Thesis, Paris 8, 2016. http://www.theses.fr/2016PA080096.
Der volle Inhalt der QuelleThe concept of resilience has been adopted by the language and practices of growing global urbanisation, the dominant model of which is planning. However, resilience theory is also questioned, notably for the difficulty it manifests in ensuring predictable results, or for the usage that is made of it by the most neoliberal approaches to planning. This thesis shows that concept of resilience can also be a starting point for questioning planning by introducing other ways of understanding, theorising and designing urban environments. It addresses how urban resilience theory can shed light on specific conceptual frameworks, whose criteria may orient design choices. The research originates in a corpus that has been developed in the field of ecology, opening the way to an urban resilience theory, and explores the singularities of this transition. To overcome the dominant model’s tendency to blur landmarks, and free this process of theorisation from the ambiguity of its frameworks, this thesis adopts the method of analysis through metaphor. It thus proposes the concept of "urban piracy", as an art of designing resilience in urban environments. The metaphor of piracy is constructed along its etymological sense, its archetypes and its history. It gives way to a theorisation that includes the qualitative aspects of the conditions of resilience; the relationship to form, time and place, of a city designed according to its criteria; the symbolism of its theory and its discrepancies vis-à-vis the dominant model; its political, dialogical, experimental and incremental dimension; and finally, the landmarks and the thresholds that orient choices in architectural and urban design
Génin, Alexandre. „Réseaux d'interactions écologiques, stabilité et résilience des écosystèmes“. Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTG031/document.
Der volle Inhalt der QuelleEcological systems are not simple but composed of many different elements(species, for example) interacting with each other. These networks ofinteractions exhibit structural properties that determine ecological systems’ability to absorb and recover from perturbations. Mappinginteractions along with their changes in time and space is therefore key tounderstand and predict empirical communities' response to global changes.In this thesis, we used plant communities as model systems (i) to explore howspatial patterns may help identify feedbacks loops which make communities morefragile to upcoming changes and (ii) to map species interactions in empiricalcommunities and describe how they change along stress gradients and recover fromperturbations. To do so, we used two datasets documenting plant communities insubalpine meadows (USA) and Mediterranean grasslands (France).Our results show that feedback loops can be inferred to some extent from thespatial patterns of plant communities and hence help identify communities thatmay respond more abruptly to perturbations. Going to a more detailed level ofdescription, plant-plant interactions (as measured through spatial associations)were shown to respond strongly and consistently to stress but exhibited a weakresilience to disturbances.This work shows that plant-plant interactions -- which are linked to the response of the community to perturbations -- can be uncovered using spatial patterns. It paves the way towards a better understanding and a better anticipation capacity of how ecological communities might reorganize when subject to disturbances
Lagarde, Adrien. „Économie écologique pour une soutenabilité et résilience écosystémique des pêches face aux changements globaux“. Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0214.
Der volle Inhalt der QuelleAchieving the various objectives of sustainable development, including notably the conservation of the oceans and a sustainable use of fishery resources constitutes a challenge for industrial and artisanal fisheries around the world. Global changes, which affect the ecological and economic dynamics of marine and coastal ecosystems, significantly complicate the achievement of these objectives. By taking into account ecological, economic and social criteria linked respectively to the maintenance of fishery biodiversity, the economic viability of fisheries and food security, this thesis aims at identifying fishing management strategies allowing to ensure the sustainability and resilience of marine fisheries.The research is based on two case studies: the industrial fisheries of the Bay of Biscay and the small coastal coral fisheries of French Polynesia. Several ecological-economic models are developed and calibrated. Dynamic, spatially explicit, multi-fleet, multi-species and stochastic, these models take into account the complexity of the interactions specific to the socio-ecosystems studied, while being part of the family of models of intermediate complexity for ecosystem-based fisheries management. The model parameters are calibrated using both local data relating to the two case studies, and climatic data. The choice of fishing effort as a system control variable takes into account the relative flexibility and diversity of regulatory tools specific to the management systems studied. Particular attention is paid to the multi-species fishing strategies that are the Multi-Species Maximum Economic Yield (MMEY), the Multi-Species Maximum Sustainable Yield (MMSY) or Eco-viability. The strategies, scenarios and projections derived from the models are compared using ecological and economic criteria of sustainability, resilience and viability such as maintaining the profits of the fishing activity over time, maintaining the food production on which island and coastal populations depend and the conservation of ecological functions and biodiversity.Beyond the models, fishing strategies and scenarios constructed for the 2 case studies, this thesis presents a series of important transversal results: first, the analysis highlights the need for temporal, spatial, by species and by type of fishing reallocation of fishing efforts for the sustainability and resilience of marine fisheries. More concretely and precisely, this research shows that a strategy of temporal, spatial, fleet (type of fishing) and targeted species diversification, can promote the sustainability and resilience of the whole fishing system in the face of uncertainties and complexity. The MMEY, MMSY and Eco-viability stochastic strategies appear particularly relevant in this perspective. Thus a better flexibility of fishing fleets, which would depend on global uncertainties and would be function of the ecological and economic context, would support the viability and resilience of fisheries, both artisanal and industrial. In general, these different results highlight the importance of embedding the ecosystem approach within an ecological-economic perspective and the need to plan the development of fisheries through a multi-criteria, adaptive and resilient management in order to minimize future risks
Boiffin, Juliette. „Résilience des pessières à mousses du Québec aux incendies peu sévères : conséquences pour le cycle du carbone à long terme“. Thesis, Université Laval, 2014. http://www.theses.ulaval.ca/2014/30502/30502.pdf.
Der volle Inhalt der QuelleWildfire is a major driver of carbon dynamics in boreal forests. Immediate effects of wildfires include partial consumption of aboveground biomass and the forest floor, and carbon emissions to the atmosphere. Wildfires can also have long-term effect on carbon cycling. Indeed, when resilience of burned forests is exceeded, regenerating ecosystems differ from that of the pre-fire stands in composition, structure and biogeochemical cycles. Predictive models of carbon dynamics in boreal forests rarely take into account such multiple post-fire successional trajectories, which could bias long-term predictions of carbon storage and emissions. This study examined post-fire ecosystem resilience and carbon dynamics of black spruce-feathermoss forests of Quebec. Regeneration of black spruce, jack pine and understory plant communities were inventoried three to five years after the occurrence of a three-year episode of major fire activity in the province. In the studied plots, low burn severity had left intact a thick residual organic layer that impeded black spruce establishment. As a result, stem density of the burned stand decreased, while jack pine became dominant. Ericales resprouted abundantly. Understory regeneration was mainly driven by pre-fire site and stand characteristics. Post-fire understory composition reflected pre-fire species assemblages, because biological legacies were preserved by the low-severity fires. A model was used to simulate wildfires, succession and carbon dynamics at the landscape level, in order to assess the influence of forest floor combustion and post-fire tree regeneration on carbon cycling. After 500 years of simulation, modelling of burn severity and its influence on post-fire tree establishment caused a 13% decrease in predicted landscape carbon stocks. Simulation of the forest floor combustion alone caused a lower decrease in predicted carbon stocks than simulation of low spruce regeneration rates. Modelled fire emissions were mainly driven by variations in annual area burned. Loss of resilience of black spruce-feathermoss forests can have long-term consequences on carbon stocks. The model used in the present study could be further improved by incorporating explicit simulation of understory species dynamics.
Stathopoulos, Marco. „La résilience urbaine : art de la crise et architectures pirates“. Electronic Thesis or Diss., Paris 8, 2016. http://www.theses.fr/2016PA080096.
Der volle Inhalt der QuelleThe concept of resilience has been adopted by the language and practices of growing global urbanisation, the dominant model of which is planning. However, resilience theory is also questioned, notably for the difficulty it manifests in ensuring predictable results, or for the usage that is made of it by the most neoliberal approaches to planning. This thesis shows that concept of resilience can also be a starting point for questioning planning by introducing other ways of understanding, theorising and designing urban environments. It addresses how urban resilience theory can shed light on specific conceptual frameworks, whose criteria may orient design choices. The research originates in a corpus that has been developed in the field of ecology, opening the way to an urban resilience theory, and explores the singularities of this transition. To overcome the dominant model’s tendency to blur landmarks, and free this process of theorisation from the ambiguity of its frameworks, this thesis adopts the method of analysis through metaphor. It thus proposes the concept of "urban piracy", as an art of designing resilience in urban environments. The metaphor of piracy is constructed along its etymological sense, its archetypes and its history. It gives way to a theorisation that includes the qualitative aspects of the conditions of resilience; the relationship to form, time and place, of a city designed according to its criteria; the symbolism of its theory and its discrepancies vis-à-vis the dominant model; its political, dialogical, experimental and incremental dimension; and finally, the landmarks and the thresholds that orient choices in architectural and urban design
Jardim, Arruda André. „Seed ecology and grassland resilience : the case of campo rupestre How have we studied seed rain in grasslands and what do we need to improve for better restoration?“ Thesis, Avignon, 2019. http://www.theses.fr/2019AVIG0353.
Der volle Inhalt der QuelleOur knowledge of tropical old-growth grassland resilience (i.e. resistance to degradation and capacity for recovery) remains limited relative to our knowledge of temperate grasslands. Although highly resilient to endogenous disturbances such fires, the vegetation dynamics in old-growth fire-prone tropical grasslands seems hampered by anthropogenic disturbances, especially topsoil degradation. After topsoil disturbance, the internal species pool (i.e. remaining vegetation and the seed bank) is often depleted or even absent, and natural regeneration depends mainly on seed dispersal from surrounding sites via the seed rain. However, plant communities on areas disturbed by soil removal can remain very different from preserved sites many years after degradation, with almost no recovery of the natural vegetation. Despite extremely relevant, seed dispersal dynamics and resilience of tropical old-growth grasslands after soil disturbance remains much overlooked. In this thesis, I carried out a review and three experimental studies about seed rain and diaspore removal dynamics in grasslands. In CHAPTER1, I did a systematic literature survey about seed rain studies in global grasslands. I (1) assessed where, how and why research on seed rain has been carried out; (2) examined how methodological design and results have been reported; and (3) provided guidelines for future research on seed rain in grasslands. I found a remarkable unbalance in the numbers of studies between grassland types, which becomes even more dissimilar across global climatic ranges when the area covered by each grassland type is take into consideration. I identified significant knowledge gaps in grassland seed rain research. I also found a great disparity of methods and data being reported across studies. Additionally, I found that only a few attempts have been made to assess the seed trap efficiency and no studies to date have proposed any protocol to evaluate the effectiveness of seed sorting methods. Then, in CHAPTER 2, I ran a field experiment to propose a simple standard protocol to evaluate the efficiency of two seed trap types (sticky and funnel traps) and of a seed sorting method to assess the efficient of the methods prior to seed rain studies. As a case of study, in CHAPTER 3 and 4, I studied seed rain and secondary diaspore removal dynamics in preserved areas and in areas degraded by gravel exploitation for road construction in campo rupestre vegetation, a megadiverse edaphic grassland in southeastern Brazil. The small number of seeds captured in the seed rain, indicates seed limitation and suggests a close causal relationship between seed dispersal limitation and the low resilience after soil disturbance. The identification of some relatively abundant species in the seed rain places these species as good targets for reintroduction in future restoration projects. Topsoil removal changed the identity of ants interacting with diaspores, resulting in contrasting outcomes from ant-diaspore interactions. The lack of diaspore removal towards degraded areas indicates that establishment limitation is a factor hampering natural regeneration. Our findings help to explain, at least partially, why natural regeneration is compromised after soil removal, which strongly influences diaspore fate and interactions with potential ground-dwelling dispersers, resulting in different ecological outcomes and strong influencing vegetation dynamics and regeneration. I expect that these results will guide future research on seed dispersal and resilience in grasslands, underpinning decisions on restoration and conservation practices on these threatened environments
O nosso conhecimento sobre a resiliência (isto é, resistência à degradação e capacidade de recuperação) de savanas tropicais permanece muito aquém do nosso conhecimento já adquirido sobre as savanas temperadas. Savanas tropicais, embora altamente resilientes à perturbações endógenas, como o fogo, se mostram extremamente vulneráveis à certas perturbações antrópicas como a degradação do solo, a quais podem ocasionar drástica alteração da dinâmica da vegetação. Após a perturbação da camada superficial do solo, o conjunto interno de espécies (isto é, a vegetação remanescente e o banco de sementes) são frequentemente reduzidos ou até mesmo completamente eliminados. Nestes casos, a regeneração natural depende principalmente da dispersão de sementes da vegetação do entorno através da chuva de sementes. No entanto, comunidades vegetais em áreas perturbadas pela remoção do solo podem permanecer, mesmo após vários anos ao distúrbio original, muito diferentes do ecossistema de referência, apresentando baixíssima capacidade de regeneração natural. A dinâmica de dispersão de sementes em savanas tropicais, apesar de extremamente relevantes para uma melhor compreensão sobre a resiliência desses ecossistemas frente a ações antrópicas, permanece pouco estudada. Nesta tese, realizei uma revisão e três estudos experimentais sobre a dinâmica da chuva de sementes e da remoção de diásporos no campo rupestre, uma savana tropical natural, megadiversa e muito antiga localizada no sudeste do Brasil. No primeiro capítulo, realizei uma pesquisa bibliográfica sistemática sobre estudos de chuva de sementes em áreas não florestais no mundo com os seguintes objetivos: (1) avaliar onde, como e por que as pesquisas sobre chuva de sementes foram realizadas; (2) examinar como o desenho metodológico e os resultados foram relatados; (3) fornecer diretrizes para futuras pesquisas sobre chuva de sementes em áreas não florestais. Nesta revisão, eu encontrei um notável desequilíbrio no número de estudos entre os tipos diferentes tipos de áreas não florestais, o qual se torna ainda mais notável em relação à distribuição dos estudos entre as faixas climáticas globais e em relação à área total recoberta por cada ecossistema (ex. savanas tropicais). Neste estudo, foram identificadas algumas importantes lacunas de conhecimento relativas a estudos sobre a chuva de sementes em áreas não florestais. Foi evidenciado também uma grande disparidade entre os métodos de estudo de chuva de semente e sobre a maneira de reportar os dados observados, o que dificulta comparações entre estudos. Verificamos que apenas algumas tentativas foram feitas para avaliar a eficiência das armadilhas de captura de sementes e que nenhum estudo até o momento propôs algum protocolo para avaliar a eficácia dos métodos de captura de sementes utilizando armadilhas de sementes para áreas não florestais. No segundo capítulo, foi proposto e testado um protocolo simples para avaliar a eficiência de dois tipos de armadilhas de sementes (armadilhas pegajosa e de funil) e a eficácia de um método de busca e triagem de sementes coletas em armadilhas de funil, os quais podem ser realizados previamente aos estudos de chuva de semente. Como casos de estudo, no terceiro e quarto capítulos, pesquisei a dinâmica da chuva de sementes e de remoção secundária de diásporos em áreas preservadas e em áreas degradadas pela exploração de cascalho para a construção de estradas na vegetação do campo rupestre. O pequeno número de sementes capturadas na chuva de sementes indica limitação na dispersão de sementes e sugere uma estreita relação causal entre a limitação de dispersão de sementes e a baixa resiliência observada nestas áreas degradadas após a perturbação do solo.A identificação de espécies relativamente abundantes na chuva de sementes coloca essas espécies como potenciais alvos para futuros projetos de restauração visando a reintrodução de espécies
Blier-Langdeau, Ariane. „La réponse au feu des communautés végétales d'une tourbière ombrotrophe restaurée“. Master's thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/35465.
Der volle Inhalt der QuelleOmbrotrophic peatlands (bogs) are known to be Carbone sink partially because of their resistance and resilience to fire. In a global climatic change context with politics aiming toward a reduction of atmospheric Carbone emission, a quick restoration of every degrade peatlands is desirable. The Canadian horticultural industry developed a promising peatland restoration technique. More than 100 sites were restored in Canada and despite many success indicators, we still hope that restored peatlands are resistantandresilient to fire. Indeed, few studies assess an ecosystem response to a disturbance happening after restorationandnone evaluates the response to fire of restored peatlands. At the end of summer 2014, a fire occurred in a Southern Quebec bog, partially burning a ten years old restored sectoranda natural one nearby providing the first opportunity to study the response to fire of a restored peatland. This research is divided in two objectives: 1) determine if the peat accumulation potentialandplant cover are the same between the burnedandunburned parts of the restored sector one growing season after fireand2) compare the mosses strata recovery between the naturalandthe restored sectors. The phytobiomass production rate was similar between the burnedandunburned parts of the restored sectorandthe burned parts plant cover growths significantly during the first growing season after fire, even reaching a similar level as the unburned parts for some areas. Sphagnumhummocks of the restored sectors showed a better resistanceandrecovery than the one in the natural sector. Thus, this study shows a tendency to resilience to fire of restored ombrotrophic peatlands.
Wuillot, Jean. „Résilience des cours d'eaux tropicaux : réponse des Baetidae (Ephemeroptera) au traitement du Niandan (Guinée) par insecticides antisimulidiens“. Lyon 1, 1991. http://www.theses.fr/1991LYO10126.
Der volle Inhalt der QuelleBernard, Lionel. „Mécanismes fonctionnels de résilience des prairies subalpines au changement global“. Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAV010/document.
Der volle Inhalt der QuelleAlpine grassland ecosystems are presumed to be highly sensitive to climate change, yet their long history of climate variability, and multiple centuries of land use may have selected for mechanisms of ecological resilience to climate variability and climate extremes. We used a large experimental design to explore patterns and mechanisms for responses of subalpine grasslands to combined winter (snow removal) and summer (drought) weather extremes depending on plant functional composition and management. Plant functional composition was manipulated by establishing grass mixtures with three species representing a conservation to exploitation gradient planted at varying relative abundances. Overall, functional composition was the primary determinant of all observed parameters for plant individual performance, intraspecific plant trait responses, litter decomposition and nitrogen recycling processes. The functioning of grassland ecosystems dominated by conservative plants was remarkably resistant to extreme weather treatments, while grassland ecosystems dominated by more exploitative plants were more resilient. Management altered these responses mostly in the case of exploitative communities. Belowground allocation to carbohydrate reserves and to microbial nitrogen pools were identified as two key mechanisms underpinning these resilient responses. Longer-term impacts of climate change may however unfold through the exhaustion of plant reserves and decreasing nitrogen returns to soils via decomposition process
Assaf-Medawar, Eleni. „Les potentialités des interfaces « bâti/non bâti » dans une approche de résilience territoriale et environnementale : recherche appliquée aux Zones d'Activités Economiques de la rive droite du Var (Alpes-Maritimes)“. Electronic Thesis or Diss., Université Côte d'Azur, 2024. http://www.theses.fr/2024COAZ2010.
Der volle Inhalt der QuelleThe thesis addresses the overarching challenge of enhancing the long-term general resilience of the peri-urban territory located on the right bank of the lower Var Valley (06), spanning from Le Broc to Saint-Laurent-du-Var. This area encompasses diverse functions such as housing, agriculture, industry, and natural spaces, all coexisting without functional interrelation. Economic activity zones play a predominant role in this landscape, with the Carros industrial zone alone hosting 600 companies and providing 10,000 jobs.This territory has been rightly considered for several decades as a strategically important area, as indicated by the Regional Land Use Plan (DTA) of Alpes-Maritimes and the Plaine du Var Urban Development Project (OIN Eco-vallée). In reality, it is subjected to intense, difficult-to-regulate urban pressure, particularly affecting agricultural spaces. Moreover, industrial parks present a paradox as they are both dynamic and aging. However, initiatives undertaken inside the industrial parks, such as the approach to industrial and territorial ecology, are typically conducted independently in each park, with little or no connection to neighboring spaces. Conversely, these industrial areas are aging, facing increasing land scarcity and constraints, and landscape quality is neglected. The dynamics of change are further constrained by strong regulatory pressures related to various risks (flooding, fire, technological).The thesis takes the stance that the organization of built and non-built spaces represents an untapped potential for environmental and territorial resilience. The entire right bank of the Var is structured as a nesting of interfaces at different scales: built/non-built; urban/agricultural; agricultural/urban/natural; urban/natural; and agricultural/natural. These spaces harbor substantial potential, especially considering that local economic players view them merely as opportunities to expand economic activities. Instead, these spaces could be perceived and utilized innovatively to enhance the territory economically, socially, and environmentally by creating "recycled landscapes". Implementing such developments not only contributes to the overall ecological enhancement of the territory but also enhances its socio-economic aspects by improving quality of work life and internal functioning, promoting, for instance, soft mobility
Fleurant, Maismy-Mary. „Les changements climatiques à Haïti : pour la résilience socio-écologique des populations par l’adaptation dans le domaine de l’agriculture. Possibilités et limites du droit interne et international“. Doctoral thesis, Université Laval, 2020. http://hdl.handle.net/20.500.11794/66597.
Der volle Inhalt der QuelleThe thesis focuses on Haiti’s implementation of the international legal climate regime with the aim of adapting this country's agriculture to climate change. The general research question raised is to what extent the national legal framework, in line with international legal mechanisms, contributes to the socio-ecological resilience of the populations of Haiti to climate change through adaptation in the field of Agriculture. In response to this question, we hypothesized that the inadequacies and poverty of the national legal and institutional framework and the weaknesses in the implementation of the international legal framework do not contribute to the resilience of the people of Haiti to climate change and adaptation in agriculture. International environmental law is only really effective to the extent that it is implemented at the national level. For developing countries facing great financial and technical difficulties, facilitation remains the best way to achieve this implementation. In our work,we have sought to understand the role of existing national law in achieving Haiti’s objective of resilience and adaptation to climate change in agriculture. We questioned the implementation of international law by this country by analyzing and criticizing the legal measures and institutional reforms undertaken to allow the conventional environmental standard to be effective. We also analyzed the action of the facilitation mechanisms of the international climate and desertification regimes responsible for facilitating technical and financial assistance to developing States Parties, assistance without which a small island developing State like Haiti will find it difficult to achieve its adaptation objectives. This critical analysis of national law, of the way in which the implementation of international law was conducted and of the value of facilitation led us to formulate proposals for modification of the legal and institutional framework with the objective of socio-ecological resilience. ecological of the populations of Haiti by adaptation in the field of agriculture. These proposals were made, after a comparative approach to the implementation of international law by the Dominican Republic, a small island state neighboring Haiti and facing the same challenges of adaptation to climate change.
Roux-Barthès, Amélie. „Biofilms phototrophes de rivières non permanentes : dynamiques de communautés microbiennes et des populations de diatomées et pertinence de leur utilisation en bioindication“. Toulouse 3, 2014. http://thesesups.ups-tlse.fr/2494/.
Der volle Inhalt der QuelleNon permanent streams are an important part of hydrographic network in the world that has been neglected. In the context of Global Change, the study of the communities of non permanent streams becomes a central concern. While the Water Framework Directive requires to member states the monitoring of their water bodies, non permanent streams are outside the scope of standardized protocols when riverbeds are dried, notably those based on benthic diatoms. To improve management policies, it is essential to enlarge knowledge on the dynamics and recolonization processes of phototrophic biofilms, including benthic diatoms, subjected to variable drought intensities. Communities are constrained to adapt to emersion stress thanks to different strategies such as physiological adjustments. Emersion stress is usually associated with others disturbances such as grazing pressure or increasing of UV radiation which can induce an additional pressure for biofilm survival. It can also impact the recolonization processes. For a better understanding of the dynamics of phototrophic benthic communities, we conducted various experiments in controlled conditions and in situ. We showed that drought stress has a strong and durable impact on communities, even after the stress removal, whatever the drought duration. We also noted a great functional resilience despite a non structural resilience which shown a great biofilm plasticity. Diatoms are efficient bioindicators for the assessment of water quality in the world. However, recent works have highlighted uncertainties in the protocol application, from sampling to determination. Owing to the problems of protocol application in dry riverbeds, we tested the reliability of diatom index values associated with different counting methods. Our results show that only a slight modification of the protocol is necessary to adapt BDI to sampling and analyses on dry riverbeds. This allows great perspectives for this application at higher scale
Gomes, Pierre. „Résilience du microbiote ruminal : influence de la source d’énergie alimentaire et du phénotype chez la chèvre et la vache“. Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASA012.
Der volle Inhalt der QuelleA better understanding of the relationship between the host animal and its ruminal microbiota would be the first step to optimize the balance between the use of fiber in ruminant feed and methane production. Two elements of this relationship were studied in this thesis: (1) the structural resilience of the microbiota after a ruminal ecosystem disturbance depending on the dietary energy source, and (2) the microbiota host specificity linked to rumen input and output flows. An innovative procedure of synchronization was developed consisting of emptying, pooling across animals and refiling rumens with the mixed rumen contents. This creates a ruminal ecosystem disturbance and provides the same microbiota to all animals. This procedure was used in 3 experiments on 12 dry goats, 10 lactating goats and 6 dry cows. Bacteria and archaea communities were assessed by 16S rRNA gene sequencing. The rumen microbiota evolved towards a different composition from the one before synchronization in the 2 species fed with a high fiber content diet. On the other hand, with diets rich in fast fermentable carbohydrates or starch, the microbiota of the 2 species go back to compositions close to the initial one before synchronization. Thus, the dietary energy source influences the structural microbiota resilience. A part of the microbiota host specificity is explain by the input and output flow of organic matter in the rumen
Leruste, Amandine. „Trajectoires d’évolution des communautés phytoplanctoniques au cours du processus de restauration écologique des milieux lagunaires méditerranéens“. Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT143/document.
Der volle Inhalt der QuelleLocated at the interface between marine and continental systems, coastal lagoons are among the most diverse and productive ecosystems. These semi-enclosed ecosystems are very vulnerable to nutrient enrichment. In the Languedoc-Roussillon region, anthropogenic pressures have profoundly damaged the coastal lagoons, especially those belonging to the Palavasian complex close to Montpellier. The latter lagoons have been affected by high nutrient loadings from the sewage treatment plant of the Montpellier agglomeration. This resulted in a trophic gradient among the eight lagoons in the complex, from mesotrophy to hypertrophy, with altered primary producer communities by favoring the predominance of the phytoplankton compartment.The phytoplankton responds very fast to environmental variability. The high specific and functional diversity of the phytoplankton carries information regarding the different ecological processes and ecosystem functioning. Hence, phytoplankton has been widely used as an efficient indicator of aquatic ecosystems functioning.In December 2005, the effluents responsible of the eutrophication of the Palavasian lagoons were diverted into the Mediterranean Sea. This measure resulted in a reduction of the inorganic phosphorous and nitrogen loadings to the lagoons from 70 to 83 %, respectively, and initiated a process of ecological restoration. This thesis aimed to improve the understanding of the restoration process of Mediterranean coastal lagoons by studying phytoplankton communities’ trajectories.The analysis of a database comprising fourteen years of observations from 2000 to 2013 established that the restoration of coastal lagoons gave rise to an improvement of the water quality, linked to a drastic reduction of phytoplankton biomass. The time series showed a sharp drop of the Diatoms (3-5 µm), which before the diversion had been particularly enhanced by the nutrient inputs from the effluents. The analysis of phytoplankton trajectories since the nutrient inputs reduction showed a modification of phytoplankton community composition characterized by an increase of the abundances of Green algae and Dinophytes. This modification reflects the change of the origin and the form of available nutrients caused by the re-oligotrophication. It especially emphasizes the importance of benthic fluxes of phosphate and ammonium, for which Green algae are the most competitive. In addition, the benthic stocks of organic matter may represent a resource for mixotrophic species. Picophytoplankton, which was exclusively dominant in the Palavasian lagoons before the diversion, is now temporarily replaced by nano- and microphytoplankton during seasonal blooms. This is related to their specific strategies to acquire and use nutrients. The seasonal variability of taxonomic and functional phytoplankton diversity (cell size, trophic regime, growth) of two lagoons from the Palavasian complex with contrasted trophic status was studied in more detail, and compared to that of an oligotrophic lagoon. This study showed some particularities of the phytoplankton communities to fit to distinct ecosystem functioning, which can be linked to the degradation caused by eutrophication. The restoration is still unfinished today. The phytoplankton biomass increases since 2012 in response to suitable climatic conditions. The phytoplankton of the Palavasian lagoons still quickly responds to a nutrient pulse, highlighting the lagoon vulnerability to an anthropogenic nutrient input
Mirabel, Ariane Sandrine. „Réponse et résilience de la biodiversité d'une Forêt Tropicale après Perturbation Inescapable Taxonomists : Workable Biodiversity Management Based on a Minimum Field Work Post-Disturbance Tree Community Trajectories in a Neotropical Forest 30 Years of Post-disturbance Recruitment in a Neotropical Forest“. Thesis, Guyane, 2018. http://www.theses.fr/2018YANE0006.
Der volle Inhalt der QuelleForest are currently threatened by the global changing context. Maintain the goods and services they provide require clarifying tree community diversity response to disturbance, that determine forest functioning, maintenance and resilience. This is specifically crucial in tropical forests that are both the most threatened regions and those with the highest environmental, social and economic stakes. In this context, this work studies the taxonomic and functional response to disturbance of a Neotropical community. Through post-disturbance diversity trajectories in the long term we examined the ecological processes underlying community response to disturbance, explicit the taxonomic and functional aspects of community recovery, and eventually discussed some perspectives for forest management and modeling. From the monitoring dataset of the Paracou experimental station in French Guiana we examined tree community response to disturbance over the thirty years following a disturbance gradient. First, we developed and tested a diversity estimator tackling the taxonomic uncertainties of forest inventories and improving the accuracy of biodiversity surveys. The estimator based on botanical/vernacular association probability to account of taxonomic uncertainties in various diversity measurement framework. The estimator, further used in this worked, was first calibrated to improve the estimation accuracy and was then validated with real forest inventories. The results allowed designing an inventory protocol optimizing the cost of inventories and the accuracy of the diversity measure. Second, we analyzed the post-disturbance taxonomic and functional trajectories of diversity, composition and redundant at the scale of the whole community. We combined the 30 years of botanical inventories with a large functional dataset encompassing key leaf, root, wood and life-history functional traits. Eventually, we specifically analyzed the post-disturbance recruitment processes and the diversity and composition succession.We highlighted the emergence after disturbance of deterministic processes driving community taxonomic and functional response to disturbance. Deterministic processes favored the recruitment of a restricted pool of pioneer species, similar for to all communities and disturbance intensity. Around fifteen years after disturbance, the recovery of community initial characteristics started with the recovery of stochastic processes driving non-disturbed communities. At the whole-community scale, this succession translated into a cyclic trajectory of taxonomic composition leading to a recovery of the pre-disturbance composition and a maintenance of differences among communities. Disturbance increased both taxonomic richness and evenness until an intensity threshold above which, in accordance with the Intermediate Disturbance Hypothesis, the taxonomic richness decreased and the pioneers became persistently dominant. The functional trajectories however proved decoupled from taxonomic trajectories. Functional diversity increased whatever the disturbance, without any intensity threshold, and functional composition trajectories converged in the functional space without marked differences among communities. This decoupling was explained by the functional redundancy that mitigated the functional impact of disturbance and proved to be the slow parameter of tropical forest recovery.Our results showed a tangible taxonomic and functional recovery of communities after the gradient of disturbance but this recovery proved decades-long. In the light of those results, we discussed the practices of sustainable forest management and several perspectives of forest diversity modeling
Borsali, Amine Habib. „Contribution à l’évaluation de l’impact des incendies sur les écosystèmes forestiers : cas de la Forêt de Fénouane , Commune d’Ain El Hadjer, Wilaya de Saida ( Algérie)“. Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4362.
Der volle Inhalt der QuelleWithin this research was to evaluate dynamic return to short and long-term of the physicochemical and microbiological properties of the burnt grounds and to study to become to it burned vegetable communities. For the study of the ground we analyzed the physical properties, chemical and microbiological of 25 samples of ground taken in the Forest of Fénouane (Wilaya of Saida, Algeria) along a chono-sequence of 2,4,8,13 and 20 years after last. This study made it possible to show the vulnerability of the forest grounds of the semi-arid stage of the Tellian Atlas at the frequencies of fires higher than 1 fire every 20 years. For the study of the effect of fire on the composition of the pine forests with Pinus halepensis Mill.de the forest of Fénouane (Algeria) one used the same small squares and chrono-sequence that selected for the study of the ground. Floristic statements were carried out according to the method sigmatist according to the last fire. The comparative method showed a progressive reconstitution of the pine forests without much variation in their floristic composition. In fact practically the same species existed before fire which reappears afterwards. It arises from the phyto-ecological study that the forest of Fénouane is very fragile and the little of plant species which it contains could decrease to reach a critical level because of the climatic and edaphic aridity accentuated by the fires and the overgrazing
Capdeville, Cécile. „Evaluation des capacités de résistance et de résilience de l'écosystème mangrove en réponse à des apports d'eaux usées domestiques prétraitées“. Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30093/document.
Der volle Inhalt der QuelleMangroves are coastal forests in (sub)tropical regions, located in the intertidal zone. They provide a many ecosystem services to human societies and neighboring ecosystems (resources, habitats, protection). Mangroves are continually affected by natural stresses (salinity, temperature, tidal cycle) but they are also subjected to anthropogenic effluents (aquaculture, urban centers). It was suggested that mangroves may be used for the bio-epuration of domestic wastewaters. This thesis aims at providing elements that will help defining the framework for this specific usage of a natural ecosystem and evaluating the long- and short-term resistance and resilience abilities of mangroves subjected to an anthropic disturbance. To reach these objectives, we used an experimental system set up in the largest mangrove of the island Mayotte. In this system, pretreated wastewaters (PW) are daily discharged in two mangrove zones dominated by Ceriops tagal or Rhizophora mucronata. Several sampling campaigns allowed to monitor in situ the impact of nutrient and freshwater excess on vegetation, crabs, meiofauna, and microbial communities and to determine their resistance and resilience capacities. In this work, PW strongly stimulated vegetation growth, altered the structure of crabs and meiofauna, modified the microbial structure and increased microbial density and activity of microorganisms involved in nitrogen cycle. However, no major dysfunction of the ecosystem (loss of vegetation, strong decrease in crab density) was observed. The monitoring of the ecosystem during two years after the PW discharge was stopped showed a marked ability of the mangrove to recover from the disturbance. Finally, the results indicate that R. mucronata mangrove zone, less disturbed, is more able to receive discharges for bio-epuration of domestic PW by mangrove ecosystem
Grac, Corinne. „Fouille temporelle des indicateurs physico-chimiques et biologiques pour l'évaluation de l'état, des pressions et de la capacité de résilience des rivières“. Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAH015.
Der volle Inhalt der QuelleData from the assessment of river are big data, with complex relationships. Unsupervised data mining methods can be applied on them and give relevant results for their management, if a close collaboration exists between hydroecologists and computer scientists. The extraction of partially ordered patterns from temporal sequences of physicochemical pressures preceding a biological state has been achieved. These temporal patterns allow to identify a part of the pressures involved or not in a degraded ecological status, to specify the importance of the sequences time-length before a biological assessment, to identify the characteristic pressure categories at a regional scale. To go further, we plan to extend these patterns to hydromorphological pressures
Ben, Sassi Meriem. „Impacts d’apports de composts de déchets urbains sur la résistance et la résilience de la microflore du sol à des évènements de type canicule/sécheresse“. Thesis, Avignon, 2012. http://www.theses.fr/2012AVIG0639/document.
Der volle Inhalt der QuelleCurrent climate change and increasing populations’ growth enhance soil and ecosystem services vulnerability. Meteorological models predicted an increase in summer drought and higher air temperature with more frequent occurrence of extreme events like heat-waves and drought. Intensity and duration of these events may affect structure and functions of ecosystems and thereby the biodiversity and the functions of soil. The amendment of soils with composts could be an alternative to prevent and mitigate the effects of drought and heat waves in the Mediterranean agroecosystems. The objectives of this work were to characterize the effects of short and long-term high temperature and/or drought perturbation on soil Mediterranean microbial communities (structures and functions) and to study the impacts of compost amendment on short and long-term functional and taxonomic responses of microbial communities subjected to drought and high temperature. Our work allowed us to evaluate the influence of each factor (drought or high temperature) within the combined perturbation (drought and high temperature) on microbiological and physico-chemical soil properties. The effects of this combined perturbation induced similar or different responses of each of perturbations applied individually involving positive and negative effects on the microbial community. This work had shown threshold resistance duration inducing a change in taxonomic and functional microbial community structure after high temperature and drought perturbation. This abrupt shift in the community response did not allow resilience. Compost amendments improved the physico-chemical soil structure and stimulated indigenous soil microorganisms. However, it seemed that seasonal soil variations history rather than compost amendment influences soil microbial stability
Bachand, Marianne. „Résilience des sapinières aux surabondances des grands herbivores : le contrôle des densités permet-il le retour des composantes taxonomiques et fonctionnelles de l'écosystème?“ Thesis, Université Laval, 2013. http://www.theses.ulaval.ca/2013/30174/30174.pdf.
Der volle Inhalt der QuelleWe combined specific and functional approaches of biodiversity to capture the impact of deer densities on communities of Anticosti Island. With the specific approach, 12 plants, 11 moths and one bird have been identified as indicator of 12 specific patterns of deer densities. The use of plant combinations in comparison with single plant species added indicators for 17 deer density patterns and increased our capacity to estimate deer density. Then, functional syndromes at high and reduced deer densities were identified through analysis of functional traits of communities. For example, plants at high densities (> 15cerfs/km²) had a vegetative reproduction and abiotic pollination and dispersal. They are traits involving few interactions with animals, which could affect the maintenance of biodiversity. In addition, after eight years of succession, reduction of deer density on Anticosti did not allow the return of species composition similar to the one found in a reference stand of balsam fir forest. However, communities at reduced deer densities had similar composition of functional traits to the reference. Finally, the indices of species diversity (e.g. Shannon) did not change according to deer density but the indices of functional diversity (e.g. Rao) did. For example, the variance of some traits, such as vegetative reproduction, was reduced at high deer density. Low variance of a trait can affect the resilience of ecosystems to new disturbances. These results provide a glimpse for the return of afunctional Balsam fir forest on Anticosti Island when deer densities are controlled.
Mohieddinne, Hamza. „Impact du tassement actuel et ancien par les engins sylvicoles sur les pédosystèmes et la végétation“. Thesis, Amiens, 2019. http://www.theses.fr/2019AMIE0020.
Der volle Inhalt der QuelleForest soil rutting and compaction by heavy machines is one of the most important issues concerning the sustainable management of forest. In this thesis, we examined the soil rutting in a forest massif on Northern France (Compiègne forest) using airborne LIDAR (Light Detection And Ranging), then we evaluated the recovery of soil after compaction at multi-decades’ scale. The Digital Terrain Models (DTM) treated using the Local Relief Modelling tool (LRM) were used to suggest an indicator of rutting density (RD). The physical and biological recovery of soil were evaluated using two chronosequences (Podzol and Luvisol) established adopting a space for time substitution approach and covering a period of 45 years. The parameters used to examine the recovery were: the penetration resistance, the soil respiration, the pH, the hydromorphic features, the rooting, and the microarthropod diversity evaluated by the QBS-ar index. As results, the impacted surface by rutting was 40% on average, where it varies at fine scale within the forest management unit. The occurrence of many herbaceous species varies with respect to the rutting density. The surface respiration and the microarthropod diversity were recovered in 10 years on the horizon of 0-10 cm. The penetration resistance showed a progressive recovery starting from the surface to the deeper layers. The complete recovery, of the first 30 cm, was evaluated to be achieved in 60 years for the Luvisol, and in 80 years for the Podzol
Buchheit, Pauline. „Le recueil de multiples finalités de l'environnement en amont d'un diagnostic de vulnérabilité et de résilience : Application à un bassin versant au Laos“. Electronic Thesis or Diss., Paris, Institut agronomique, vétérinaire et forestier de France, 2016. http://www.theses.fr/2016IAVF0008.
Der volle Inhalt der QuelleLao PDR is a landlocked country with low population density, which stands nowadays in a process of regional economic integration, after suffering wars related to decolonization and Cold War during several decades. A very fast economic growth, based on the development of infrastructures of transport and natural resource exploitation, has led to large differentiated impacts on populations and their resource based livelihoods. The concepts of resilience and vulnerability have been used in different disciplines to analyze and manage the dynamics of geographical areas and social groups facing rapid and uncertain changes. Both concepts are used within a variety of frameworks of analysis of society-environment relationships. While all reviewed frameworks take into account multiple scales of analysis in order to tackle the complexity of the studied phenomena, they do not, however, assess vulnerability and resilience at the same scales. In particular, some frameworks are actor-centered, while others are system-centered. The scale and limit of the socioecological system whose resilience or vulnerability is assessed depend on the issues that the authors want to tackle. Before such an assessment, it seems necessary to identify the issues of resilience and vulnerability that we want to address. This task should not be taken over by scientists alone, but by other stakeholders as well. The question is: how can we incorporate multiple viewpoints in the system design? For this, our framework considers a socioecological system both as a specific representation of the environment offered by a stakeholder, and as a set of elements contributing to one function. This system is organized in a hierarchy of levels of observation, in which each level corresponds to an intermediary function. We developed and tested a process to collect system representations of the environment from various stakeholders, that is to say, the way they structure a socioecological system that makes sense to them, according to the purposes that they assign to their environment. This approach has been tested in the catchment area of the Nam Lik river, Fuang district, Vientiane province, where the Nam Lik 1-2 hydropower dam was built in 2010. A series of workshops were held with residents of the study area, employees of local government and Lao National University teachers. At the earliest stage of a vulnerability or resilience assessment in the field study, this thesis proposes a reflection on the possible framings of these concepts, as well as methods to collect them from multiple stakeholders
Delavat, François. „Composition et fonctionnement d'une communauté microbienne au sein d'un drainage minier acide : approches culturales et fonctionnelles“. Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00797981.
Der volle Inhalt der QuelleGarcia, Pierre-Olivier. „Sous l'adaptation, l'immunité : étude sur le discours de l'adaptation au changement climatique“. Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAH025/document.
Der volle Inhalt der QuelleClimate Change Adaptation (CCA) is a category of thought and action. It clusters every practice that seeks to deal and cope with the territorial consequences of climate change. It is proposed in this work to study the discourse of adaptation to CC and to provide immunity as an alternative approach.The first part of this study investigates how this discourse -here defined as the whole set of statements concerning CCA- is set into a specific order. Because of its heterogeneity, this discourse may initially be characterised as opaque. Yet, the study of its evolution along the one of the scientific journal Global Environmental Change, highlights the emergence, over the 2000’s, of the resilience paradigm. This very paradigm reconfigures and sets the CCA discourse into a specific order. From then on, adaptation is no longer understood as the meer adjustment to external climatic stimuli, but as the social group own adaptativity, defined as the capacity to let itself be restructured by any internal or external change.The second part of this study argues in favour of considering immunity as a tacit but nevertheless highly structuring notion within the CCA discourse and within geography and planning theory. Immunity is first approached theoretically by exploring the philosophical anthropology of P. Sloterdijk, that he happened to name general immunology. In order to transfer immunity into geography and planning theory, the sloterdijkian theoretical tools are then discussed and built on with other approaches, including F. Neyrat’s and R. Esposito’s work. Eventually, studying the case of the Netherlands reveals how immunity is at the heart of the order of some specific milieu. Indeed, this country is a paradigmatic case of a planning tradition that immunises society from its geographical milieu and an example of the implementation of CCA public policy.This thesis puts into perspective two contradictory main principles of the contemporary ordering of the milieus: absolute immunity and adaptativity. It shows how CCA resolves this contradiction in a very specific way
Caimi, Annalisa. „Cultures constructives vernaculaires et résilience : entre savoir, pratique et technique : appréhender le vernaculaire en tant que génie du lieu et génie parasinistre“. Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENH011/document.
Der volle Inhalt der QuelleIn areas prone to natural hazards, many of the buildings that make up the built environment are constructed almost exclusively through the experience and the direct observation of local builders, without the support of any architect or engineer. In these regions, communities have developed over time a variety of strategies to cope with natural phenomena through patterns of social behaviours and building approaches intended to prevent and/or to reduce their exposure to local risks. Similarly, local builders have often integrated natural hazards into their daily practices, developing singular techniques, building details or devices aiming to reduce the vulnerability of the built environment. The concept of building culture embraces the social and technical aspects related to the construction process and to the development of corresponding knowledge and know-how, intrinsically reflecting the multiplicity of human societies and their indissoluble connection with the territories they inhabit. The vernacular as characterization of ways of building, living and protecting oneself proves to be a valuable source of practices, techniques and measures, tested over the years and during multiple hazards, for contemporary construction of sustainable, accessible and safe built-environments. This research explores the potential of vernacular building cultures in enhancing local resilience; and this starting from - constructive and behavioural – practices developed by individual people and groups living in contexts geographically exposed to natural hazards. Based on a strong interaction between theory and action, this research undertakes a (re)discovery of vernacular knowledge through two thematic focuses. One examines disaster resilient vernacular provisions and devices which have demonstrated their effectiveness to reduce vulnerability of the built environment to various types of natural hazards. The other one considers ways for their identification and direct contribution to strengthening capacities of communities and institutions for disaster risk management. This research combines a technical analysis with the development of a methodological tool, contributing to set up a project approach strongly rooted into contextual specificities, linking culture and practice, past experience and future needs, disaster response and preparedness
Gallien, Manon. „La résilience des Systèmes Alimentaires de qualité différenciée : approche pour la compréhension des dynamiques de protection de la qualité de l'eau en agriculture“. Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE2067/document.
Der volle Inhalt der QuelleIn 2009, The Grenelle de l'Environnement (French environmental pact) introduced environmental clauses within Geographical Indications (GI) specifications. French Water agencies (agences de l’eau) perceive it as a good opportunity to address the issue of agricultural pollution, by takings actions at the upstream level. In this context, this study examines how certainfood quality processes are proactively setting targets for conserving water. This question led to develop a global approach in order to look at the issues of water quality from the wider angle of environmental preservation. It requires not only to focus on regulation tools of food quality products but also to take into account a larger set of environmental actions. Along the same lines, the theoretical framework of the resilience of food system of differentiated quality has also been developed. It allows to study proactive environmental dynamics set up by stakeholders to deal with perturbations linked to natural resources degradation, such as water. Those perturbations can be factual (measured) or represented, when stakeholders consider a potential risk. This analytical framework has been applied on case studies in viticulture and fruit production in the South-East of France. The results underscore the complexity of environmental dynamics: they are based on a set of complementary actions and require the mobilization of key players, able to engage in a collective dynamics but also to have a wider vision of food systems, both by looking at the vertical dimension (market oriented) and horizontal dimension (link with the local territory)
Ampou, Eghbert Elvan. „Caractérisation de la résilience des communautés benthiques récifales par analyse d'images à très haute résolution multi-sources : le cas du parc national de Bunaken, Indonésie“. Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30305/document.
Der volle Inhalt der QuelleThe INDESO (Infrastructure Development of Space Oceanography) project, in collaboration with the Indonesian Government (Ministry of Marine Affairs and Fisheries - MMAF) and the French company CLS (Collecte Localisation Satellites), promotes the use of space technologies for monitoring coastlines and Indonesian seas. This thesis is part of coral reef monitoring component, led by the IRD (Institute de Recherche pour le Développement). The main objective was to determine wether coral reef habitats on Bunaken Island in Northern Sulawesi are resilient, using (i) newly desgined habitat maps, (ii) in situ data, and a unique 15-year time series of satellite images of different very high resolution (VHR) sensors, and (iii) ancillary data that could explain the changes detected. The results include highly detailed maps of the Bunaken reefs habitat (194 polygons mapped and a census of 175 habitats). The influence of sea level fall on coral mortality during the El-Nino event of 2015 - 2016 is presented in detail, and the importance of this process is also discussed from the interpretation of a unique time series of 15 years of VHR images. The temporal series reveals very different trajectories of the coral habitats. We conclude that Bunaken reefs demonstrate an ability to resileince and without phase shift, but that a definitive diagnosis of their resilience remains difficult to determine by imagery. Habitat trajectories can not be fully interpreted without changing some monitoring paradigms and without using a combination of remote sensing and in situ data
Petit, Marie-Eléonore. „Pérennité, fonctionnalité, efficacité d'une zone humide artificielle (ZHA) en milieu méditerranéen : un nouvel écosystème au service du traitement secondaire des effluents industriels“. Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0439/document.
Der volle Inhalt der QuelleNatural wetlands in Mediterranean areas are rare and vulnerable ecosystems, frequently impacted by various pollutants from nearby environments. In order to decrease industrial activities lethal effects on natural areas, constructed wetlands (CWs) are an interesting opportunity to remediate their pre-treated wastewaters. Such CWs would take advantage with using local plant species, well adapted to Mediterranean climate’s rigors. Nevertheless, CWs planted with Mediterranean plant species are still scarce and poorly studied. Aims of this thesis are thus:• to follow up on planted and adventive biocœnosis of a CW (flora, fauna and phytoplankton), in order to assess a novel ecosystem settlement,• to get better knowledge on its functions and remediation efficiency (physico-chemical and biological parameters),• to question durability of such techno-ecosystems in a context of global changes (with focus on climate).Main result let us know that it only takes a few local plant species, wisely chosen, to allow the settlement of a sustainable and fully functional ecosystem, supporting biodiversity stakes while increasing the remediation of pre-treated wastewaters collected from industrialized catchment. This work assess CWs planted with local helophytes as a powerful tool to treat industrialized catchment wastewaters in Mediterranean area, but researches are still needed to fit each design with each site characteristics, following a sustainable ecological engineering approach
Gueneau, Stéphane. „Vers une évaluation des dispositifs de prise en charge du problème du déclin des forêts tropicales humides“. Thesis, Paris, AgroParisTech, 2011. https://pastel.archives-ouvertes.fr/tel-03690042.
Der volle Inhalt der QuelleDocument 1: Presentation of the doctoral research dossierThis document presents the general framework of the doctoral research dossier. It intends to briefly explain the research methodology, in order to better understand the dual approach adopted and the structure of this doctoral research. On the one hand, the dossier is based on several articles published on the issue of forest certification schemes political transformations. On the other hand, the dossier includes a research on the issue of environmental effectiveness of rainforest management devices. This first document introduces the critical stand, the issues addressed and the disciplines involved in these two approaches. Finally, the prospects offered by this research are mentioned.Document 2: Political transformations induced by the development of forest management certification: the case of FSC.This document analyses the political impact of a forest management certification device: the Forest Steward Council (FSC). It integrates five articles published in academic/scientific books and journals between 2007 and 2011, which were published in the framework of the NORMES research project “Regulation by standards : the instruments of regulations in the governance of sustainable development”, financed by the French National Agency of Research (ANR). The publications are preceded by a framing text which presents the background and the working of the FSC-instrument, and then introduces the texts succinctly.The research activities permit to enhance the understanding of political transformations, induced by the FSC. The institutional innovations which were produced by the FSC will be emphasized, as well as the reach and the limits of this voluntary instrument, the behavorial changes it brings about, and the side-effects it generates, in particular in terms of equity between the concerned players in this field.Finally, the analysis of the public-private relations shows that, far from being a private and isolated instrument, the FSC exerts a certain influence on the elaboration of public politics, and, reciprocally, its development is conditioned by a certain degree of governmental intervention.Document 3: Laying the bases of a benchmark for assessing the devices which corner the deforestation and rainforest degradation problems.This document concentrates on the issue of effectiveness of the devices which tackle the problems of deforestation and rainforest degradation. The starting point of this work is the problem-solving difficulties, despite repeated international statements and devices adopted in recent decades.Based on these observations, the research focuses on evaluation frameworks that would assess the environmental effectiveness of such devices. It starts with a critical analysis of the theoretical framework used to address global environmental issues, specifically the effectiveness of global environmental regimes theories (Underdal, 1992, Young, 1998). Then, an extensive literature review on the rainforest management issues is presented, showing the complexity of the problem. The research pointed out the failures of the current approaches implemented to tackle the deforestation and rainforest degradation. Finally, by using the framework of the Strategic analysis of environmental management (Mermet 1992, 1998, Mermet & a, 2005, 2010), this study demonstrated that despite the complexity of the deforestation and rainforest degradation problem, it is legitimate, useful and possible to construct a referential for evaluation focused on environmental challenges that forests are facing. The basis of this framework is laid out, by detailing the principal elements that will be able to frame the evaluation of the effectiveness of the management of these forests
Albert, Sébastien. „Rupture des interactions mutualistes plantes à fruits charnus-vertébrés frugivores, et conséquences sur la régénération des forêts tropicales dans les Mascareignes“. Thesis, La Réunion, 2020. http://www.theses.fr/2020LARE0035.
Der volle Inhalt der QuelleTropical forests are mostly dominated by fleshy-fruited plants, which are dispersed by frugivorous vertebrates. The global collapse of large vertebrates therefore raises questions about the resilience of these ecosystems, particularly on islands, which concentrate the bulk of extinctions. The Mascarenes are a remarkable system to study disruption of frugivory interactions because the pristine fauna, plethoric until human colonization in the 17th century and now largely extinct, is well known as well as its diverse flora which is particularly at risk. La Réunion is still home to indigenous forests along strong environmental gradients and active volcanism that offers the opportunity to explore the long-term consequences of defaunation. In addition, the varying levels of vertebrate extinctions between La Réunion (main extant frugivore, mass=55 g) and Mauritius (450 g) makes itpossible to use these islands as pseudo-replicates to test various hypotheses. This thesis is organised in three parts which aim to (1) describe the spatial distribution patterns of dispersal traits on La Réunion and Mauritius, and understand the implications for vertebrate extinctions which have been particularly rapid on La Réunion; (2) evaluate the consequences of frugivory disruption on the reconstruction of forest ecosystems on the lava flows of the Piton de la Fournaise; (3) assess the consequences of frugivory disruption on the maintenance of diversity in forests established before human colonisation. (1) Proportions of fleshy-fruited plants strongly decrease with elevation and this decrease is all the more pronounced the larger the fruit are. By comparing the main factors of vertebrate extinctions between La Réunion and Mauritius, we show that the early destruction of favorable lowland habitats on La Réunion probably played a central role in the rapidity of frugivore extinctions. (2) After expanding the chronosequence of the Piton de la Fournaise flows, we show thatfrugivore extinctions have profoundly altered the capacity of lowland forests to rebuild since the 18th century and that the refaunation of ecosystems with alien frugivores mainly benefits alien fleshy-fruited plants. Reinstating dispersal, native large-seeded plants are nevertheless capable of settling on historical flows where recruitment is overwhelmingly dominated by invasive plants. (3) By comparing two reference forests of La Réunion and Mauritius, we show that the Mauritian flying fox allows a much better recruitment of many plant species at Brise-Fer than the Réunion bulbul at Mare-Longue, except for large-seeded plants which regenerate poorly in both islands. An experiment finally shows how the persistence of fruit flesh alone can strongly limit tree recruitment, but that the latter can be modulated by introduced fauna. Our overall worrying results show the urgency to protect large native frugivores wherever they still exist and of encouraging their return where they had disappeared. At the same time, large-scale sowing should be envisaged in protected areas where the maintenance or even the return of native forest dynamics are imperative
Tromeur, Eric. „Concilier enjeux écologiques et économiques pour une gestion écosystémique des pêches“. Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS409.
Der volle Inhalt der QuelleOverfishing affects the structures and dynamics of many marine ecosystems, as well as the associated ecosystem services. To tackle this issue, many scientists and managers are calling for an ecosystem-based fisheries management, integrating the complexity of harvested ecosystems, and based on ecological and economic sustainability objectives. In that perspective, our aim is to build an ecosystem approach to fisheries management, reconciling biodiversity and resilience preservation with the maintenance of high yields and profits. To this aim, we develop bio-economic models of mixed fisheries, composed of species that are either independent or in trophic interactions. We show that maximizing the aggregate catches or profits of a mixed fishery can threaten the biodiversity and resilience of harvested ecosystems, but that economic instruments can address these issues. In uncertain systems, risk aversion also helps reconciling constrasting management goals. We then apply multi-objective management approaches to identify the best strategies from an ecological and economic point of view. Chosen strategies depend on managers' preferences: favoring production implies to focus harvest on small trophic levels, while favoring biodiversity or resilience implies to focus on higher trophic levels. We therefore suggest that diversified fishing patterns could allow reconciling ecological with economic objectives, in order to achieve a sustainable ecosystem approach to fisheries management
Piton, Gabin. „Résilience des écosystèmes prairiaux aux stress climatiques selon l'intensité de gestion. Une approche par le concept de trait fonctionnel microbien Using proxies of microbial community‐weighted means traits to explain the cascading effect of management intensity, soil and plant traits on ecosystem resilience in mountain grasslands The resilience of soil microbial communities to climate change-induced rain regimes differs between conventional and ecological-intensive managed soils across European agroecosystems Implementing ecoenzymes in the trait framework bring new insights on the microbial communitiy composition control on ecosystem functioning“. Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAV070.
Der volle Inhalt der QuelleIn the current context of climate change, associated with increases of climate extremes frequency and intensity, understanding the ecosystem response to climate variability is a central challenge in ecology. Soil microbial communities control most ecosystem processes driving energy and nutrients fluxes. In the context of agriculture management, an important question is to understand the influence of farming practices on soil microbial communities and their capacity to maintain ecosystem functioning under climate change. Ecological-intensive agriculture has been recently proposed as an approach integrating ecological processes in management strategies to optimise agroecosystems functioning and resilience to climate change. Functional ecology might be relevant to address these challenges associated with climate change and ecological-intensification of agriculture.In this PhD thesis, I used the functional trait framework to grassland ecosystems to address how different modalities of management intensity (extensive, conventional-intensive, ecological-intensive management) influence: 1) functional parameters of soil microbial communities; 2) the capacity of these soil microbial communities to maintain ecosystem functioning during and after climatic stresses (Resilience). During my PhD, three experiments have been conducted using different degrees of control of management factors and simulating different kind of climatic stresses, with different durations. Based on grassland agroecosystems in three countries across Europe (France, Switzerland, Portugal), results from the first two experiments of this PhD showed that ecological-intensive management select soil microbial communities with a lower capacity to maintain microbial ecosystem properties during stresses (resistance) but with higher capacity to recover compared with soil microbial communities of soils under conventional-intensive management. Moreover, another study showed that ecological-intensive management promotes beneficial proteolytic soil microbial communities for plant nitrogen uptake under climate change-induced rain regimes. Plant functional traits assessment suggest this management effect on microbial communities composition and resilience to be explained by higher litter phosphorous content in ecological-intensive systems. Indeed, this plant functional trait affect microbial traits, favouring copiotrophic microbial community characterized by a lower nitrogen:phosphorous ratio of their biomass and a lower investment in extracellular enzymes production, two traits decreasing stress resistance but increasing recovery capacities. Thereby, these two experiments stress the relevance of plant traits management to control soil microbial traits and the resilience of soil microbial communities to climate changes. A third experiment tested specifically the impact of a mineral fertilisation event on the resilience of soil microbial communities to different climatic stresses. Results clearly demonstrated that fertilization modify soil microbial community composition and soil microbial traits and decrease ecosystem stability under climatic stresses.Implementing an approach based on the microbial functional trait concept, this thesis brings new insights on the effects of management intensity on grassland ecosystem resilience to climatic stress
Coiffait-Gombault, Clémentine. „Règles d’assemblages et restauration écologique des communautés végétales herbacées méditerranéennes : le cas de la Plaine de La Crau (Bouches-du-Rhône, France)“. Thesis, Avignon, 2011. http://www.theses.fr/2011AVIG0322/document.
Der volle Inhalt der QuelleMediterranean herbaceous ecosystems which are characterized by a high biodiversity have been submitted to a lot of changes in use. Their conservation is not sufficient enough and ecological restoration seems to be an adapted solution to improve conservation efforts as it can mitigate damages induced by human activities. To develop restoration methods adapted to these ecosystems, preliminary researches on the different communities composing an ecosystem and the filters which are responsible for community assemblage before and after disturbance are necessary. Representative of numerous Mediterranean steppe ecosystems, the “Coussouls de Crau” and their ex-arable-fields (Bouches-du-Rhône, France) are the biological models used to identify and study the principal filters potentially responsible for organizing the plant communities. Sheep grazing, trophic changes, competition and reproduction and /or species dispersal, were identified in a first study on steppe regeneration; these filters were then the core of the following three research experiments. We carried out two in-situ restoration protocols (hay transfer and sowing foundation species) and one ex-situ experiment testing interactions between a selection of steppe species. The main results show that reproduction, seed dispersal, soil trophic level, competition, extensive sheep grazing are filters which have a determinant role in structuring the communities, in determining plant composition and partly in explaining the slow dynamics towards the reference steppe. Also, we show that filters interact between them. For applied restoration, the tested methods promote steppe vegetation come back, but in the short term (two or three years after restoration), the composition of restored areas remains different to the reference ecosystem. Even if we understand better the different factors which explain community organization, these results demonstrate that it is difficult to restore it integrally because it is not easy to manipulate and find an equilibrium between the different filters actions. Now it is necessary to continue these fundamental and applied researches, in particular on the maturation and structure of the old herbaceous plant communities
Hernandez, Pauline. „Effet d'une sécheresse extrême sur le fonctionnement de l'écosystème prairial : évaluation du rôle tampon de la composition et de la diversité végétale par approche expérimentale“. Thesis, Clermont-Ferrand 2, 2016. http://www.theses.fr/2016CLF22752/document.
Der volle Inhalt der QuellePermanent grasslands are one of the main forms of land use in Europe. In France, permanent grasslands represent around 40% of Utilised Agricultural Land and support many animal-based farming systems. Current climate change scenarios predict increased climate variability that could result in an increase in extreme events such as drought episodes. These extreme events can significantly alter the structure and functioning of grasslands, with implications for their capacity to provide agricultural, ecological and environmental services. Improved understanding of the resistance and resilience mechanisms of grassland plant communities exposed to extreme drought is therefore critical in order to assess the stability of grassland functions, in particular that of biomass production. This thesis aims at assessing the capacity of permanent grasslands to sustain their production when exposed to an extreme drought event. The study uses an experimental approach and semi-controlled conditions to investigate the role of community composition and functional diversity for drought resistance and resilience in grassland mixtures. Monocultures and mixtures combining grasses and legumes were selected to test the importance of composition and functional diversity for plant community responses during drought and up to a year after the end of water stress. The originality of this work is the use of a functional ecological approach to assess the impacts of species’ interactions via measurements of plant morphological and physiological traits both above- and below-ground. This study demonstrates the importance of white clover (Trifolium repens) in modulating the impact of extreme droughts on biomass production of grassland mixtures. Community composition did not have a buffering effect on biomass production during the drought event but the presence and abundance of white clover in mixtures was linked to higher recovery of biomass production in the long-term. After the extreme drought event, overyielding in mixtures combining grass and white clover could be attributed to mechanisms of nitrogen facilitation and vertical root complementarity for water uptake. Results also show the importance of deep root growth for the establishment of functional complementarity between species and the maintenance of biomass production under extreme drought. Drought had lasting effects on the root system patterns and thus on the underlying mechanisms of the positive effect of white clover on aboveground production. Moreover, this work highlights the key role of heterospecific interactions in the expression of intraspecific traits related to resource acquisition strategies. Heterospecific interactions are thus an important driver of the species performance under extreme drought.We show that the structure and functional composition of the plant community in simplified mixtures are critical for modulating grassland responses to an extreme drought event. In our study, the recovery of aboveground biomass production is mainly related to the presence of white clover and the establishment of positive interactions between species. Changes of species behaviour in response to heterospecific interactions should be taken into account to better predict grassland biomass production under future climatic conditions. From an applied perspective, accounting for the key role of white clover and the inherent variability or neighbour-induced plasticity of intraspecific traits appears important to adapt mixtures of species or varieties to more intense and frequent drought events
Gascon, Emilie. „Conception par l'opportunité pour des villes éco-résilientes aux inondations“. Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLD002/document.
Der volle Inhalt der QuelleIn recognition of the limits of the possibilities of combating floods, a vision of “Living With” floods is developing. The aim is no longer to resist water, but to allow it into the territory and adapt. This strategic approach opens the way to a positive vision of flood risk, in which the opportunities associated with floods can be envisaged.In this context of “Living With”, this piece of research seeks to theorise and promote the emerging method of opportunity-based design as applied to flood eco-resilient cities. This thesis therefore examines how:1. the concept of opportunity constitutes an approach within the theoretical framework of flood eco-resilient cities;2. the opportunity-based approach constitutes a method of design and offers advantages, relevance and potential for the design of flood eco-resilient cities, in particular by comparison with the most common method of risk management.The purpose of this thesis research is to formalise the method of opportunity-based design through a representational tool—an observation grid— in order to facilitate the use and promotion of such design. In order to communicate on —but above all to exploit the results— of the method, a grid for the observation of the strategies associated with urban and landscape projects for opportunity-based design is investigated. This instrument, in particular aimed at architectural, urban and landscape designers, is developed by means of a semantic map. Semantic mapping is the methodological solution employed in this research. It is used to explore and connect the multiple data collected, and to organise them so that their complexity can be understood. The observation grid therefore maps the method employed and constitutes a tool for implementation in opportunity-based design.On the one hand, the results obtained from this research demonstrate, first, that the opportunity-based approach offers potential for design in response to the complexity of urban flood territories. Through diversity and proactiveness, it would seem to be relevant in achieving the balance between natural phenomena and human activities. On the other hand, the risk-based and opportunity-based approaches are different but complementary. What emerges from the mapping process is that the design of flood eco-resilient cities entails a balance between risk and opportunity.Second, these results show that opportunity-based design reflects a logic that generates virtuous cycles between landscape features (soil, vegetation, etc.) and fundamental flows (water, energy, waste, nutrients, etc.) for the production of socio‑eco-environmental benefits. The basis of its action is to reconnect cities with their territories by articulating, in a multifunctional, interdisciplinary and multitemporal way, the synergies between the physical elements of urban territory. It is particularly relevant in that it formulates a new, balanced relationship between human and hydro-ecological systems and offers the potential for a new societal perspective.To sum up, the first important conclusion is that semantic mapping is an effective research tool in that it facilitates the handling and analysis of complex data. The second is that the method theorised, together with the observation grid developed, constitute a change in flood-related design practices. And finally, this thesis establishes a refined theoretical and practical starting point for challenging the risk management paradigm and pursuing further research into flood eco-resilient cities and into “Living With” floods
Jaunatre, Renaud. „Dynamique et restauration d’une steppe méditerranéenne après changements d’usages (La Crau, Bouches-du-Rhône, France)“. Thesis, Avignon, 2012. http://www.theses.fr/2012AVIG0324/document.
Der volle Inhalt der QuelleEcosystem restoration has been identified as one approach to slow down the loss of biodiversity and to protect all the biodiversity-based goods and services from which humankind benefits. Restoration feeds from knowledge coming from both community ecology and restoration ecology. The objectives of the thesis are to provide insights on both the dynamics of a mediterranean steppe after changes in land-use and the implementation of techniques which could be applied to restore this ecosystem after severe anthropogenic disturbances. The thesis takes as a study object the La Crau Mediterranean steppe, and especially former cultivated fields to study the recovery after cultivation and the Cossure large scale rehabilitation project to experiment rehabilitation and restoration techniques. Concerning dynamics after severe exogenous anthropogenic disturbances, we confirmed the low resilience of the steppe plant community both at mid- (30-40 years) and long-term (150 years) while the resilience of soil parameters and mycorrhizal infestation rate are effective on the long-term. Moreover we confirmed the role played by the three filters in the plant community recovery and found that for the La Crau steppe, this is firstly driven by the abiotic filter, then by the dispersion filter and finally by the biotic filter. Given this low resilience, we tested several restoration techniques applied at large-scale within the Cossure rehabilitation project: nurse species seeding, topsoil removal, hay transfer and soil transfer. In order to assess the efficiency of restoration techniques we developed indices to measure the community structure integrity, disentangling lower and higher abundances compared to the reference. The best results were obtained with soil transfer, followed by topsoil removal, then nurse species seeding and finally hay transfer. The research conducted for this thesis shows that current knowledge in ecological restoration makes it possible to restore at least partially some La Crau ecosystem components, but ought to lead us to understand the importance of in situ conservation of natural habitats as a better alternative to restore them after they were destroyed
Longépée, Esméralda. „La résilience des systèmes socio-écologiques des États atolliens dans le contexte du changement climatique : le cas de Kiribati (Pacifique Sud)“. Thesis, La Rochelle, 2014. http://www.theses.fr/2014LAROS007/document.
Der volle Inhalt der QuelleThe threats to states entirely composed of atolls from climate change and associated sea-level rise have been widely publicized. The Republic of Kiribati is an atoll country situated in Pacific Ocean settled by 100,000 inhabitants. Over the past centuries, the atoll communities of Kiribati have developed natural resource management systems that have enabled their survival. Over the past decades, globalization has caused rapid changes, especially regarding lifestyles and relationships of atoll communities to their natural environment. Given the highly integrated nature of the societal system and the ecosystem in the atolls, this thesis addresses the question of the future of atoll countries in the context of climate change by studying the resilience of their social-ecological systems. Resilience is the capacity of a system to absorb disturbance and reorganize while undergoing change so as to still retain essentially the same function, structure, identity, and feedbacks. This thesis postulated that an assessment of social-ecological resilience of climate- and marine-related disturbances required a preliminary analysis of their general resilience. Such assessments are based on conceptual models made from interviews and surveys and from the analysis of aerial imagery. The future of atoll countries is discussed considering different scenario: adaptation, transformation, migration and collapse
Vander, Vorste Ross. „The hyporeic zone as a primary source of invertebrate community resilience in intermittent alluvial rivers : evidence from field and mesocosm experiments“. Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10259/document.
Der volle Inhalt der QuelleUnderstanding community response to disturbance is essential to identifying processes that determine their assembly and to predicting the future effects of climate change on biodiversity and ecosystem functions. Drying (complete loss of surface water) is a natural disturbance affecting 50% of rivers worldwide and is occurring more in perennial rivers due to climate change. However, its effects on aquatic invertebrate communities and the underlying processes contributing to their resilience (i.e. return to pre-drying or undisturbed levels) have not been well quantified. Using 4 congruous field and mesocosm experiments to quantify community resilience and identify its primary sources in environmentally harsh alluvial rivers. First, I found communities in 8 alluvial rivers were highly resilient to moderate and severe drying. Second, I showed that the hyporheic zone (saturated interstitial sediments) can be the primary source of colonists, promoting high community resilience. Third, I found high water temperature and intraspecific competition caused Gammarus pulex, a common benthic detritivore, to migrate into the hyporheic zone. Fourth, I found increasing depth to the water table diminished the hyporheic zone’s role as a source of colonists by reducing survival of G. pulex. My results support an emerging concept that harsh ecosystems are highly resilient and indicate that the effects of drying on biodiversity and ecosystem functions could vary across river systems. In alluvial rivers, the hyporheic zone can contribute strongly to community resilience and management should focus on protecting and restoring vertical connectivity to maximize resilience to climate change
Delfy, Aladin. „paramètres et dispositifs dans la construction de l'habitat durable : le cas de l'écoquartier de Bonne à Grenoble“. Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAG042.
Der volle Inhalt der QuelleOur research addresses the general issue of urban development and how to design sustainable cities through architecture and town planning. Our analysis focused on a study of caserne de Bonne, an ecodistrict located in Grenoble, which is an emblematic city from an ecological viewpoint. Our task was to significantly reduce CO2 gas emissions, limit the greenhouse effect, and preserve biodiversity. We developed our hypothesis to devise satisfactory solutions to fight pollution, reduce the use of fossil fuels, and create innovative ways to employ renewable energy. Our program will start locally, then expand on a regional and national level. We observed that in residential districts, remedies such as reducing transportation generated pollution, conserving energy, treating household waste, and other parameters,can be scaled up and implemented regionally and nationally. As architect and urban planner, we wanted to contribute to this field by providing an analysis of Bonne ecodistrict
Mestre, Irene. „La contribution de la gestion communautaire des ressources pastorales à la résilience des communautés rurales post-soviétiques, le cas du Kirghizistan“. Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE3006.
Der volle Inhalt der QuelleMy research looked at pastoral resources and agropastoral systems after the implementation in 2009 of community-based pasture management over all the territory of Kyrgyzstan. I investigated how the community-based pasture management contributes to the resilience of rural communities. I used multiple embedded case-studies in order to comprehensively embrace the linkages between land-use, resource dynamics and governance. The case-studies were three rural municipalities and their pastures, which form socio-ecological systems. National level was also examined. Data-collection was conducted through extensive field-work in the rural communities, participant observation in NGOs implementing projects in the domain of pasture management at national level, and literature review. I used qualitative data analysis through thematization and basic statistic analysis for quantitative data. The theoretical framework combines the approach of Common-pool resource management by Ostrom (1990) and the resilience of spatial socio-ecological systems by Aschan-Leygonie (2000). Based on them I elaborated a qualitative framework to analyze the contribution of Community-Based Pasture Management (CBPM) on spatial resilience of socio-ecological systems. As pasture, I understand the pastures them-selves as well as all the other resources necessary for their use, e.g. water and access infrastructure. My results show that community-based management fails to create feed-back loops between the environment, the practices and the management measures. Pasture Committees do not carry out formal data collection on resource dynamics, neither on the impacts of use. Their actions merely follow pasture user interests which are potentially led by indigenous knowledge on pasture condition, although there is a need for more research on this point. However, in general, community-based pasture management positively affects the resilience of rural communities. First, by its open-nature, remote and marginalized households can take part in the decision-making. Second, the investment generated allows for repair and maintenance of infrastructure (roads, bridges) giving access to remote pasture, thereby limiting livestock concentration on most accessible pastures. Third, it creates interactions of a new type between agropastoral and non-agropastoral pasture users, as well as between local stakeholders and national-level stakeholders. Thus, community-based pasture management is a factor of the expansion of local socio-ecological systems and of the diversification and intensification of their interactions, within the systems, as well as across scales
Raccary, Bastien. „La transition écologique en chimie analytique : vers une évaluation multicritère basée sur l’analyse du cycle de vie“. Electronic Thesis or Diss., Bordeaux, 2023. http://www.theses.fr/2023BORD0223.
Der volle Inhalt der QuelleIn October 2020, a report by the European Commission revealed that 90% of Europeans are concerned about the environmental impacts of chemical products. The increasing public mistrust, worries over diminishing raw materials and energy resources, and escalating environmental pollution have driven the chemistry community to shift from a productivityfocused approach to a vision geared towards sustainability. Analytical chemistry, which lies at the heart of industrial product development, has also embraced this vision through the concept of Green Analytical Chemistry. By adopting the 12 principles of Green Analytical Chemistry and using tools to assess the sustainability of analytical methods, analytical chemists seek to reduce their environmental footprint. However, none of these tools quantitatively assess the environmental impacts throughout the entire lifecycle of a method. Life Cycle Assessment (LCA) is a recognized environmental evaluation tool framed by ISO 14040/44 standards, aimed at preventing impacts on three protection areas: ecosystem health, human health, and natural resources. LCA offers a complementary alternative to the previously published tools, though it has never been applied to the field of analytical chemistry. The objective of this thesis is to assess the relevance of LCA compared to the greenness evaluation tools and apply it to the analytical chemistry sector, evaluating the opportunities and limitations of such an approach. Two underlying themes are included in this objective: improving and enabling the quantification of environmental impacts in analytical chemistry and democratizing the LCA approach among analytical chemistry operators through the development of a user-friendly LCA-based tool. Firstly, we examine specific environmental evaluation tools in analytical chemistry by comparing them to an LCA-inspired framework. This study allows us to investigate the elements and calculation methods used by these tools to identify the potential benefits of applying LCA in the sector. Next, we apply LCA to two sample preparations to compare their respective environmental impacts and establish the relevance and feasibility of comparative analysis in analytical chemistry. LCA is then applied to a complete analytical method under two scenarios: a "business-as-usual" scenario with "conventional" analytical parameters observed in laboratories and an "eco-design" scenario incorporating optimized characteristics such as extended instrument lifespans and reduced analysis durations. This study assesses LCA's ability to quantify the influence of laboratory decision-making on its environmental impacts, promoting eco-design practices. Following these two LCAs, we propose a prototype of a multicriteria tool applicable to analytical methods. We present the tool's inputs, outputs, and general structure, while offering potential areas for improvement. Finally, while LCA provides an impact-oriented approach, a risk-based approach is necessary to avoid or better anticipate the effects of potential climate-related hazards. The laboratory is a system, and disruption within it can have repercussions on the entire activity. This risk-based approach is discussed, and clues for further development are proposed
Bornot, Yoran. „Peut-on changer les trajectoires de croissance du chêne sessile et du sapin de Douglas suite à une sécheresse en modulant la fertilité du sol ?“ Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0356/document.
Der volle Inhalt der QuelleFertilization and liming are usual practices in agronomy but uncommon in forestry. Experimental liming or fertilization in forest were tested in the 1970’s. The initial aim of these experimentations was to determine if the addition of nutrients on poor or acidic forest soil could increase tree growth or even restore crown condition in case of decline. Physiological studies have established the implication of water availability in soil nutrients uptake and their transport in the sap and also via combined effects in various processes such as cell growth or stomatal control. Recently, extreme drought events responsible of many forest species diebacks have aroused the concern of forest managers. In addition, climate models predict an increase in the frequency and intensity of drought hazards in the future and forest management must be adapted to face them. In this context, and thanks to the current knowledge on the interactions between mineral and water alimentation, we investigate whether nutrient supply could mitigate the negative effects of water deficits by increasing the capacity 1/ to withstand droughts and 2/ to recover optimum growth after the drought induced crisis, i.e. to improve the resilience of trees. Conversely, would the vulnerability of trees to water deficits be increased? To answer this question, we investigated fertilization experiments located in three forests in France and applied on two species, sessile oak and Douglas fir. On each of these sites, selected trees were cored to the pith to determine the annual variations of radial growth from measurements of the tree-rings widths. These growth variations were used as a basis to the calculation of resistance, recovery and resilience indices to drought events, which were quantified using a soil water deficit index computed by the water balance model BILJOU©. On the site of Bercé, the water-use efficiency was estimated from the δ13C of the latewood. Retrospective analyses shown that the radial growth of oak trees in Bercé and Tronçais was significantly increased after the fertilization. Radial growth was then modelled from climate and soil water deficit. Douglas fir radial growth was slightly impacted by the nutrient supply in the Potées site. This analysis highlights the time-limited effect of this nutrient supply on the growth stimulation: no effect subsists more than 10 years after nutrient supply in Bercé and more than 20 years in Tronçais. Despite this transient effect on oak growth, no differences between treatments on the capacity of trees to resist and to recover after drought events was observed. The main factors influencing resistance and recovery of growth were the soil water deficit intensity and duration. These results corroborate δ13C analyzes in oak rings, which, again, were only significantly correlated with climate and were independent of treatment. The lack of modification of the resilience between the treatments, whatever the site and the species studied, is discussed. More broadly, the concept of resilience and its use in dendroecology are questioned
Severi, Claudia. „Social sustainability and resilience of the rural communities : the case of soy producers in Argentina and the expansion of the production from Latin America to Africa“. Thesis, Avignon, 2016. http://www.theses.fr/2016AVIG0674/document.
Der volle Inhalt der QuelleSoy is one of the most important and fast growing food commodities in the global market. Thanks to the introduction of GM soy varieties, Argentina has become the third producer in the world, what entailed significant impacts at environmental, social and economic level. Objective of the study is to assess the social resilience of the rural communities cultivating soy in Argentina and to evaluate the current sustainability of the soy system. At the same time, the analysis of the expansion of the soy production from Latin America to African countries represents an element of continuity in the evaluation of the phenomenon at global level. The case study of the soy system in Argentina – strongly influenced by the introduction of GMOs and the consequent changes in land use, modernization and work organization – with its specific focus on rural communities, highlights how strongly social and ecological resilience are intertwined in the identification of mechanisms to guarantee social sustainability, which, in turn, is strictly interrelated with environmental and economic sustainability. The agricultural sector showed a good capacity of adaptation and reorganization demonstrating being economically performing, but social and environmental costs were heavy, consisting in a deep disruption of the original rural communities structure and of the original natural ecosystem. The soy system appears extremely rigid – because of the hyper specialization and the marked dependence on export – what makes it very vulnerable to changes in the international demand for soy. The current system is strongly criticized by the civil society, blaming it to be the cause of environmental problems and of health risks. To effectively contrast the negative consequences of the soy model, a significant role must be played by policy makers, who should define sustainability policies to enhance the resilience of the rural communities and to move towards more sustainable food production systems
Sukkampatti, Palanisamy Saravanan. „Empreinte géochimique urbaine dans la mégapôle de Chennai sur les sédiments de rivière : gradient amont-aval, sources et résilience“. Thesis, Tours, 2019. http://www.theses.fr/2019TOUR4016.
Der volle Inhalt der QuelleIn this study, an attempt is made to ascertain the present pollution status of Adyar and Cooum River, which are the two important rivers among the six main waterways in the Chennai Megacity, Tamil Nadu, India and greatly influenced by urbanisation in the past three decades. This study is designed 3 main objectives (i) Geochemical footprint of megacity onto river sediments (ii) Endocrine disruptor occurrence: Preliminary study for PAHs, PBDEs, PCBs and Phthalates (iii) Influence of 2015 monsoon hazard onto trace element pollution level of 2 main rivers
Coiffait-Gombault, Clémentine. „Règles d'assemblages et restauration écologique des communautés végétales herbacées méditerranéennes : le cas de la Plaine de La Crau (Bouches-du-Rhône, France)“. Phd thesis, Université d'Avignon, 2011. http://tel.archives-ouvertes.fr/tel-00943535.
Der volle Inhalt der QuelleDelfy, Aladin. „paramètres et dispositifs dans la construction de l'habitat durable : le cas de l'écoquartier de Bonne à Grenoble“. Electronic Thesis or Diss., Strasbourg, 2016. http://www.theses.fr/2016STRAG042.
Der volle Inhalt der QuelleOur research addresses the general issue of urban development and how to design sustainable cities through architecture and town planning. Our analysis focused on a study of caserne de Bonne, an ecodistrict located in Grenoble, which is an emblematic city from an ecological viewpoint. Our task was to significantly reduce CO2 gas emissions, limit the greenhouse effect, and preserve biodiversity. We developed our hypothesis to devise satisfactory solutions to fight pollution, reduce the use of fossil fuels, and create innovative ways to employ renewable energy. Our program will start locally, then expand on a regional and national level. We observed that in residential districts, remedies such as reducing transportation generated pollution, conserving energy, treating household waste, and other parameters,can be scaled up and implemented regionally and nationally. As architect and urban planner, we wanted to contribute to this field by providing an analysis of Bonne ecodistrict
Bruckmann, Laurent. „L'intégration des zones inondables dans la gestion de l'eau et le développement de l'irrigation d'une vallée fluviale sahélienne : le cas des terres de décrue de la moyenne vallée du Sénégal“. Thesis, Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCC214/document.
Der volle Inhalt der QuelleSince the decline of water resources in the 1970s, the middle Senegal river valley is a space dealing with many socio-environmental changes. Public policies have controlled the river with two dams, Manantali and Diama, and made the valley the preferred location for the development of irrigated agriculture for the national supply of rice. Faced to this situation, the floodplains wetlands, characterized by a flood/recession rythm, are forgotten by development policies. The objective of the thesis is to understand how these flood recession lands fit into socio-environmental changes, and finally to define their current roles for local populations into the reorganization of the middle Senegal river valley.The work is based on a study of the socio-ecological system of the floodplain of the middle valley. The methodology thus has several components. A hydrological analysis and a mapping of the dynamics of the flooded areas by remote sensing, showed the importance of the management choices of the Manantali dam in the allocation of water for the flood in the valley. Socio-economic surveys, carried out in four village terroirs and using semi-structured interviews, highlighted the integration of flood-recession related activities into household strategies, and define the economic, food supply and ecological functions between the different agro-ecological units of the floodplain. Finally, factors holding flood-recession related activities have been identified at household level, such as the diversity of ecosystem services, the heritage value of these areas and the integration of households in irrigation
Zwicke, Marine. „Impacts d'une canicule sécheresse sur le fonctionnement et la structure des communautés végétales de l'écosystème prairial“. Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2013. http://tel.archives-ouvertes.fr/tel-01020033.
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