Dissertations / Theses on the topic 'Niche écologique – France'
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Fried, Guillaume. "Variations spatiales et temporelles des communautés adventices des cultures annuelles en France." Dijon, 2007. http://www.theses.fr/2007DIJOS085.
Full textPoyet, Mathilde. "L'opportunité de niche favorise l'invasion de Drosophila suzukii en France." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10169/document.
Full textSuccessful biological invasion is divided into three stages: the introduction of a non-native population on a new geographical area, the establishment of viable populations and their exponential growth in the area of introduction. In 2002, Shea and Chesson proposed the Opportunity Niche Hypothesis in order to explain the success of the establishment and the spread of invasive species. According to these authors, alien species introduced into a new range can jointly benefit from a decrease of the pressure applied by natural enemies and from an increase in the availability of resources. Drosophila suzukii has been reported to be an invasive species. Native of Asia, it has been now widely observed in North America and throughout Western Europe. Since its introduction in 2008, especially in Europe, the invasion of D. suzukii is particularly rapid and, as it grows on ripe fruits, a lot of concerns have been raised on the damage it causes on crops. In our work, we have highlighted some characters of this species as elements that facilitate the success of its invasion. D. suzukii is highly resistant against parasitoids, known as its major natural enemies. We have then showed the existence of a link between the ability to resist to larval parasitoids and a high hemocyte load. Furthermore, thanks to a very large sample, we have illustrated the great polyphagia of this species. This property provides available resources throughout the year. Finally, with a study of tritrophic interactions, we have shown that the nutritional quality of host plants used by D. suzukii can have an impact on the level of resistance to entomophages. Indeed, D. suzukii increases its resistance to several species of parasitoids when it growths on an alkaloid-rich substrate. Our recent results suggest that it would even be able to achieve a form of self-medication. The different studies performed in this thesis seem to confirm that D. suzukii makes the most of niche opportunity to efficiently invade temperate Europe
Faivre, Bruno. "Coexistence et écologie de deux espèces jumelles d'hippolais." Dijon, 1992. http://www.theses.fr/1992DIJOS014.
Full textBeisel, Jean-Nicolas. "Microrépartition des invertébrés benthiques en eau courante : caractéristiques des microhabitats et organisation de leurs peuplements." Metz, 1996. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/1996/Beisel.Jean_Nicolas.SMZ9626.pdf.
Full textThe aim of this is to examine and to understand more accurately (1) the invertebrate communities organization into the different microhabitats of a river bottom, and (2) environmental factors which affect the organization of these communities. A separate sampling of microhabitats was realized on spring and autumn 1993 and 1994 in 12 stations. Community structure was summarized with biocenotic indices for which we have specify the main performances. Simulations allowed us to consider that the mesological traits of the sampled microhabitats influence strongly the appraisal of the study-site community structure, principally because invertebrates display an aggregate distribution. The study of microdistribution factors show that "substrate type", "current velocity" and, to a less extent, "water death" are of primary importance for the organization of microhabitat communities. These mesological traits focus in fact on three ecological characteristics of the habitat :(1) its capacity to offer a great variety of ecological niches for macroinvertebrates, (2) its trophic potentialities and (3) its temporal stability, which respectively determine the total abundance, the taxonomic richness and the equitability of the community. By another way, the different microhabitat types were described by specific taxa which were sampled on. This method allowed us to draw up their qualities for macroinvertebrate. An original approach of spatial heterogeneity of the substrate mosaic allowed us to show the secondary influence of the environmental characteristics of microhabitat surrounding on the community in place. The community organization seems to be related to the number of potential sources of colonization by invertebrates of neighbouring habitats, and by the stability of its environment. Finally, results obtained at a station scale demonstrate in particular that the faunistic equitability depends on the patchiness of the substrate mosaic, which probably highlights, at this scale but also at the microhabitat scale, the environmental stability concept
Coudun, Christophe. "Approche quantitative de la réponse écologique des espèces végétales forestières à l'échelle de la France." Phd thesis, ENGREF (AgroParisTech), 2005. http://tel.archives-ouvertes.fr/tel-00011330.
Full textLes données utilisées sont celles d'EcoPlant, développée à l'Ecole Nationale du Génie Rural des Eaux et des Forêts (ENGREF, Nancy) pour stocker des milliers de relevés phytoécologiques complets (relevés floristiques et caractéristiques climatiques et édaphiques précises), réalisés dans les forêts de France. La définition de 54 courbes de réponse théoriques d'espèces végétales vis-à-vis du pH, et la création de jeux artificiels de données binaires de taille variable pour essayer de re-créer les courbes de réponse théoriques, ont permis de montrer qu'il est difficile de modéliser de manière fiable le comportement des espèces peu fréquentes avec la régression logistique. En effet, nous montrons que 50 à 100 occurrences d'une espèce représentent un seuil minimal pour déterminer précisément l'optimum, l'amplitude et la probabilité maximale de la courbe de réponse écologique des espèces avec la régression logistique, ce qui justifie la nécessité de travailler avec de larges bases de données.
Pour tester la stabilité du comportement écologique des espèces sur de vastes territoires, nous avons comparé la réponse au pH du sol de 46 herbacées forestières entre le nord-est et le nord-ouest de la France, et de 21 herbacées forestières entre les Vosges et le Jura. En contexte de plaine ou de montagne, la majorité des espèces étudiées n'ont pas révélé de différences régionales marquées en terme d'optimum ou d'amplitude écologiques vis-à-vis du pH de l'horizon A du sol. Les quelques différences régionales observées ont été expliquées dans les deux cas par des conditions de compétition différentes dans chaque région. Nous concluons que l'étude de la réponse écologique peut s'effectuer sur de vastes territoires tels que la France, à condition que les conditions de compétition ne soient pas trop différentes selon les régions.
Une caractéristique majeure de la base EcoPlant est de stocker des informations édaphiques et climatiques, couplée à des relevés floristiques effectués sur les mêmes sites. L'étude conjointe de la réponse écologique des espèces végétales vis-à-vis de facteurs climatiques et édaphiques a rarement été menée, puisque la majorité des études étudient la réponse climatique des espèces végétales. Nous illustrons l'importance de prendre en compte des variables édaphiques de nutrition dans les modèles de niche écologique et de distribution géographique des plantes terrestres, par la modélisation de l'écologie et de la distribution de l'Erable champêtre (Acer campestre L.) dans les forêts françaises.
L'ensemble des résultats met en évidence l'intérêt des bases de données importantes et écologiquement complètes telles qu'EcoPlant pour approfondir la connaissance des différentes dimensions de la niche écologique des espèces à l'échelle de vastes territoires.
Cogerino, Laurent. "Les rives aquatiques de grands cours d'eau : caractérisation mésologique et faunistique." Lyon 1, 1989. http://www.theses.fr/1989LYO10136.
Full textPinto, Paulina. "Ecologie et croissance de Abies alba Mill. en peuplements purs et mélangés dans le Massif Vosgien (Nord-est de la France)." Phd thesis, ENGREF (AgroParisTech), 2006. http://pastel.archives-ouvertes.fr/pastel-00003643.
Full textBertrand, Romain. "Réponse spatio-temporelle de la végétation forestière au réchauffement climatique - Évaluation du remaniement de la végétation et caractérisation de l’effet des facteurs écologiques et géographiques le modulant à l’échelle de l’espèce et des communautés." Thesis, Paris, AgroParisTech, 2012. http://www.theses.fr/2012AGPT0065/document.
Full textClimate change is known to cause a spatial redistribution of climatic conditions which is driving poleward and upward range shifts. Such shifts imply a reorganization of plant communities which is still poorly understood. Here we aimed to assess the changes in plant communities' composition induced by climate warming at a global scale and over a long time period, as well as to analyze the effects of ecological and geographical factors that contribute to these changes at the species and community levels. The response of the forest flora to the raising temperature has been studied across the French metropolitan territory (~546,000 km²) from large floristic databases, measured and modeled environmental data, and a modeling approach based on the concept of ecological niche and the bioindicator properties of plant species. First, we showed that the reshuffling of plant communities allowed to recover 0.54°C of the temperature increase between the periods 1965–1986 and 1987–2008 in highland forests (i.e. +1.07°C), while it recovered only 0.02°C in lowland forest (warming = 1.11 °C). This partial compensation demonstrates the current occurrence of a climatic debt in forest vegetation caused by climate warming. The high climatic debt observed in lowland forest compared to the highland one is likely due to extinction and migration debts caused by a wider temperature tolerance of plants in lowland communities and a plant migration capacity (i) limited by the high spatial fragmentation of the lowland forest habitat and (ii) shorter than the shift of thermal conditions in lowland areas, respectively. The ecological and geographical specificity of lowland and highland forests led us to consider two different threats induced by climate change: (i) biotic attrition in lowland areas, and (ii) loss of a specific and an historic biodiversity in highland forest (mountaintop extinction of alpine species due the surface decrease of their potential habitat) likely replaced by more common species assemblage (increase of generalist plants). Second, the effects of abiotic, biotic and geographical factors which can amplify or reduce the magnitude of both the species range shifts and the reshuffling of plant communities induced by global warming were characterized. Last and final summary in the thesis
Leplat, Johann. "Développement saprotrophe de fusarium graminearum : rôle respectif de différents habitats naturels du champignon dans le processus d'infection du blé en Bourgogne ; recherche d'indicateurs prédictifs du risque de fusariose." Phd thesis, Université de Bourgogne, 2012. http://tel.archives-ouvertes.fr/tel-00843896.
Full textRiofrio, Dillon Gabriela. "Évolution de l'acidité et de la disponiblité en azote des sols forestiers français au cours du 20ème siècle : une approche spatio-temporelle et multi-échelle basée sur le caractère bio-indicateur de la flore." Thesis, Paris, AgroParisTech, 2013. http://www.theses.fr/2013AGPT0042/document.
Full textHuman activities have, over the last century, strongly influenced the cycles controlling the levels of acidity and nitrogen availability in nature. Acidifying and eutrophying deposition lead to a change in environmental conditions and particularly to sensitive changes in plant communities' composition.The objective of this Ph.D work is to reconstruct the spatiotemporal evolution of the acidity and nitrogen availability in French forest soils over the 20th century using the bioindicator character of plants, into local and global scales. The use of plants as bioindicator seeks to mitigate the lack of direct measurements of soil conditions and atmospheric deposition, over a wide spatiotemporal extent. First, changes in bioindicated soil pH (indicator of acidity conditions) and C:N (indicator of nitrogen availability status) were computed from approximately 100 000 temporary floristic plots carried out throughout France from 1910 to 2010. They were analyzed using an innovative method of spatiotemporal comparison, where acidic and nonacidic forest areas and coniferous and broadleaved forests were differentiated. Secondly, and always from the bioindicator character of plants, changes in soil conditions between 1972 and 2011 across Villey forest as well as floristic changes they induce related with other environmental changes were analyzed.At the global level, we observed acidification in acidic forest areas (-0.34 pH units on average) and in nonacidic areas (-0.19 pH units on average), respectively, until 1984 and 1997. We demonstrated for the first time (to our knowledge) a cessation of acidification of forest soils and even a decrease in acidity in nonacidic forest areas, as wella as a time lag for acidification between acidic and nonacidic areas. This trend is consistent with the trend of acidifying deposition in France since the early 20th century. Spatially, our results confirm the temporal trends, show a regional geographic pattern of acidification (mainly observed in nonacidic areas), and highlight the high spatial variability of soil pH changes. Concerning the evolution of nitrogen availability conditions, we observed an unexpected decrease in available nitrogen until 1984 and 1997, respectively, in coniferous (+0.79 C:N units on average) and broadleaved forests (+0.74 C:N units on average). A trend to eutrophisation of forest soils was then observed in coniferous and broadleaved forests since 1997 (-0.10 and -0.16 C:N units on average, respectively). This trend is not consistent with the trend of nitrogen atmospheric deposition in France. ”Last and final summary in the thesis.”
Gard, Benjamin. "Processus écologiques et évolutifs influençant la colonisation de l'ambroisie à feuilles d'armoise (Ambrosia artemisiifolia L.) en France." Phd thesis, Université de Bourgogne, 2012. http://tel.archives-ouvertes.fr/tel-00985748.
Full textBaltzinger, Christophe. "Sélection des sites de repos par le cerf (Cervus Elaphus L. ) et le chevreuil (Capreolus Capreolus L. ) vivant en sympatrie en forêt tempérée de moyenne montagne." Paris, Engref, 2003. https://pastel.archives-ouvertes.fr/tel-00005727.
Full textRed Deer (Cervus elaphus) and Roe Deer (Capreolus capreolus) are two abundant cervids in Europe, and they often share the same habitat. Cervids rest for about half of the time. However their bedsite selection criteria have rarely been studied. Our goal is double : i) to describe bedsite selection patterns for each species at different temporospatial scales and ii) to compare those selection patterns between species. The study took place in the Forêt Domaniale du Bougès, Parc National des Cévennes, France. Transect sampling helped us describe the characteristics of 425 bedsites, within 2 winter and 2 summer periods. PCR methodology applied to hair DNA collected on the bedsites proved to be efficient to distinguish between Red and Roe Deer. At the forest stand scale, Red and Roe Deer widely overlap in their use of different stands types as bedding sites. Both cervids tend to avoid adult coniferous stands in winter and summer. Roe Deer is less selective than Red Deer at this scale and uses forest stands relative to their availability. Red Deer is highly selective and shows a marked preference for young coniferous stands. At the microhabitat scale, Red and Roe Deer always search for good visual protection, through a well developed lateral cover. That cover is predominantly composed by conifers for the Red Deer, whereas the Roe Deer also uses deciduous cover when it is available during summer. In winter, Roe Deer beds under a large canopy cover, this cover is larger than for Red Deer. It chooses bedsites near edges whereas Red Deer rests far away from them. We discuss those differences in the selection patterns between the Red Deer, that occupies a wide home range, and the territorial Roe Deer, that lives on a more restricted range
Verollet, Anne. "Les conquérants de l’invisible- L’agglomération chambérienne à l’épreuvedu handicap visuel." Thesis, Lyon 2, 2012. http://www.theses.fr/2012LYO20113.
Full textThis thesis in sociology aims at describing the ambivalent relationship that visually impaired persons, whether they are blind or partially sighted, develop with their urban area, here that of Chambery.First, it shows that, for these disabled persons, urban space is a space where they feel locked in : the reading, the knowledge, the use of this space are restricted, submitted to imperatives such as the walking stick, the locomotion technique, the use of tools provided for them by the city. Living in the private space is also subject to many constraints. The loss of eyesight reduces ontological safety, which is altered by pain and often by loneliness.And yet urban space is the space where visually impaired persons can live and move self- autonomously. Their autonomy is made possible by two actors: on the one hand, the city which carries out urban improvements in its accessibility to conform to the law- sometimes even before the bill was passed as is the case with the city of Chambery which was rewarded for its achievements in favour of disabled persons ; on the other hand, the disabled persons themselves who need to conquer their autonomy at the expense of demanding personal efforts. “ I have to learn my job as a disabled person”, said one of them in an interview. Conquering one’s autonomy shows similarities to ‘’the real-life situation’’…. This conquest not only takes into account the environmental and situational aspect of the handicap, but it also places the blind or partially impaired person in a specific position with regard to urban space. An extension to the sociological analysis of Gibson’s ecological theory relating to perception proposes to consider visually impaired persons in a specific relationship with urban space, conjuring up the concept of ecological niche
Mastrorillo, Sylvain. "Profils écologiques du vairon (Phoxinus phoxinus L. ), de la loche franche (Barbatula barbatula L. ) et du goujon (Gobio gobio L. ) à l'échelle du microhabitat dans trois rivières pyrénéennes." Toulouse, INPT, 1997. http://www.theses.fr/1997INPT009A.
Full textLuce, Jean-Marie. "Ecologie des Cétoines (Coleoptera : Cetoniidae) microcavernicoles de la Forêt de Fontainebleau : niches écologiques, relations interspécifiques et conditions de conservation des populations." Paris, Muséum national d'histoire naturelle, 1995. http://www.theses.fr/1995MNHN0030.
Full textThe Cetoniidae to be found in Fontainebleau are members of the Coleoptera, widespread in Europe, and whose saprophagous larvas live inside cavities of hollow trees. They form a guild which plays a major part in the recycling of ligneous matter in natural forest ecosystems, and they are closely linked to the old states of sylvigenetic cycles. The biology of these species shows noteworthy features suggesting K-type strategies, which is exceptional for coleoptera insects. They undergo a strong decline given the fact they are eliminated by the common forest management. The species Osmoderma eremita (Scopoli, 1763) is part of the priority species of the European directive called " Flora and Fauna Habitats ". They can be used as bioindicators of the biodiversity in saproxylic organisms of forest-type ecosystems, because of their big size and easy identification
Planque, Yann. "Écologie trophique de deux espèces sympatriques de phoques en périphérie de leur aire de répartition." Thesis, La Rochelle, 2021. http://www.theses.fr/2021LAROS032.
Full textHarbour seal (Phoca vitulina) and grey seal (Halichoerus grypus) are two sympatric marine mammal species that are increasingly considered as potential competitors, especially at their European core distributions. The objective of this PhD was to study the foraging strategies and trophic ecology of these species at the limit of their range (Baie de Somme, Eastern English Channel, France), and to investigate the hypothesis of potential interspecific competition. Biotelemetry devices were fitted on 49 individuals to document their movements and dives at sea.The analysis of surface locations and diving behaviour, completed recently by the detection of Prey Capture Attempts (accelerometry), allowed for a better understanding of the two seal species’ foraging strategies and improved the detection of their foraging areas. Trophic niches of the two seal species were then characterised with the analysis of diet, stable isotopes (in the whiskers of the same captured individuals), and foraging areas. A high interspecific trophic overlap was identified between these niches, resulting from the consumption of benthic flatfish in coastal areas, and we suggest that it provides here the basis for potential competition between both species. This study also showed the key role of individual foraging strategies on the ecological conclusions at the scale of the species/sub-population, including that the potential competition may be due to some individual grey seal strategies. Continuing these studies is essential to detect any potential ecological changes that could be trophically-induced
Taquet, Alizée. "Évolution de la résistance aux insecticides au sein d’un complexe d’espèces de ravageurs dans un contexte d’invasion biologique : coût de la résistance et rôle de l’hybridation." Thesis, La Réunion, 2020. http://www.theses.fr/2020LARE0014.
Full textBemisia tabaci is a major insect pest distributed worldwide because of its ability to transmit phytoviruses. Three whitefly species coexist in Reunion Island: the native species IO, and two exotic species MEAM1 and MED-Q, which successively invaded the island in 1997 and 2010. The main control strategy against these species is the use of insecticides, which can lead to the emergence of resistance. The main objective was to understand the evolution of the distribution of the whitefly species, with regards to their insecticide resistance in a context of interspecific hybridization. To this aim, whiteflies were sampled in 56 sites, genotyped at 11 microsatellite markers and for two kdr loci involved in pyrethroid resistance. Fifteen populations were phenotyped for resistance to pymetrozine and acetamiprid using bioassays, and the cost of acetamiprid resistance was evaluated in MEAM1 populations displaying different resistance levels. The two invasive species are mainly found in agroecosystems and both have kdr resistance mutations. Most of the MEAM1 populations were also found to be resistant to acetamiprid, pymetrozine or both pesticides. No fitness costs appeared to be associated with resistance to acetamiprid in MEAM1. On the contrary, the indigenous species IO was mainly sampled in non-crop areas, or at the edge of agrosystems. It has no pyrethroid resistance mutations and is sensitive to the insecticides tested. Finally, the interspecific hybridization (MEAM-IO) observed between IO and MEAM1 did not lead to the introgression of resistant mutations into the indigenous species, but possibly to the introgression of susceptibility in MEAM1
E, Silva Daniel. "Ecologie du hêtre (Fagus sylvatica L.) en marge sud-ouest de son aire de distribution." Thesis, Nancy 1, 2010. http://www.theses.fr/2010NAN10136/document.
Full textIn Europe, climatic series show a global warming and an increase in frequency of summer drought. Climate is considered to be the main factor determining forest species distribution. Consequently, the zones where species are more prone to disappear in Europe are the southern margins, where current climatic conditions are the warmest and the driest of their range. So, an improved understanding of growth and health of forest tree species in these border areas becomes more than a challenge, a necessity. European beech (Fagus sylvatica), a major tree species of European forests with a broad ecological niche, represents a model species for such studies. Recent works based on statistical modelling suggested a sharp reduction of its distribution towards its core range, under future climates. Current presence of the species in lowlands strongly decreases in the south-west of France which corresponds to its southern margin in Western Europe. In this zone, spots of beech trees are however still observed in inventory databases, few stand declines have been noted and the modelled probability of presence of the species under current climate is not null. We therefore thought to redefine the distribution range concept using various descriptors and to characterize climatic, microclimatic and soil constraints that control the niche of this species