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Leroy, Clémentine. "Sensibilité des abeilles sauvages face aux transformations du paysage dans les agroécosystèmes : Utilisation d'une approche écophysiologique pour évaluer l'influence des ressources florales sur la condition corporelle des abeilles sauvages". Electronic Thesis or Diss., Avignon, 2023. http://www.theses.fr/2023AVIG0616.
Pełny tekst źródłaThe actual context of bee species decline raises the actual needs of finding and thinking about more proactive and relevant conservation and restoration measures. In this initiative, the use of new biological metrics that can link individual bee responses to environmental alteration with populationlevel responses could represent an interesting opportunity. We hypothesized that physiological indicators could communicate the actual individual bee sensitivity to environmental changes and act as early warning signals of bee population decline or sustainability. Physiological markers can for example, provide helpful information on the interface between bee populations and their resources. Those indicators are indeed very promising and already show benefits and success for numerous organisms and numerous environmental perturbations they have to cope with, namely chemicals, climate change and landscape resources. In that extent, we used such ecophysiological approach to measure the effects of floral resources abundance, availability and richness on female’s bee body condition. We approximate bee body condition as a compilation of body mass, and nutritional healthindicators (proteins, triglycerides and proteins) contents. Firstly, we examined the effect of seminatural elements (temporary and permanent grasslands, fallows and woody moorlands) on the reproductive success and the body condition of a mason bee in apple orchards from south of France. Parallelly, we tested the effect of a land-use index (compilation of farmers practices including mowing, grazing and fertilizing) and floral diversity from agroecosystems habitats on the health state of wild bee communities in Belgium and Germany thanks to the multilevel approach of the European NutriB² project. This thesis work shows that metrics of body condition can be useful to improve our understanding of pollinator responses to habitat quality with a focus on nutrition. In particular, the measure of body mass and proteins content seem to be of particular interest to attest for individual sensitivity. Additional physiological health parameters including stoichiometry and pathogen loads also provide valuable information on the health state of wild bees and are also the focus of working groups within the european project. We can optimistically assume that the acquisition of this knowledge and its application in practice, in conjunction with these other disciplinary fields and with players involved in pollinator conservation, could enable us to refine and co-construct wild bee conservation or restoration strategies to combat bee decline
Foltz, Jane. "Structure d’une communauté de propithèques de Milne-Edwards (Propithecus edwardsi) dans une forêt fragmentée malgache : approches démographique, génétique et comportementale". Strasbourg, 2009. http://www.theses.fr/2009STRA6088.
Pełny tekst źródłaHabitat destruction represents a major threat to biodiversity. Nonetheless, the highly complex interactions between habitat destruction and species extinction are poorly understood. The present study was conducted at the Ialatsara forest’s station, located in the east center of Madagascar. The total surface of this forest station is of 2500 hectares, but nowadays the natural forest only covers 500 hectares. It is divided into 6 fragments that are not connected to each other anymore. In spite of its critical state, this forest shelters the Milne-Edwards’ sifaka (Propithecus edwardsi), a strepsirrhine primate that belongs to the Indridae family. According to recent IUCN evaluations, this species is threatened with extinction (EN(A2cd)). In 2005, a preliminary census of the Ialatsara’s sifaka community counted 43 individuals divided into 8 groups. Our study is part of a conservation program aimed at maintaining and even increasing the population of Propithecus edwardsi. By means of a multi disciplinary approach we assessed the impact of forest fragmentation on the demographic and genetic parameters of the sifaka community. We also analyzed the social dynamic of this specie in such a fragmented habitat both globally and at different levels of analysis. Taken together our results are essential to determine the social system of the Milne-Edwards’ sifaka and to adjust our conservation efforts in order to set up a suitable and long-term management program
Pereboom, Vincent. "Mode d'utilisation du milieu fragmenté par une espèce forestière aux habitudes discrètes". Angers, 2006. http://www.theses.fr/2006ANGE0032.
Pełny tekst źródłaThe destruction of forests, a main issue in biological conservation, is one of the greatest threat in biodiversity worldwide. In Europe and North America, however, the maintenance of populations is put in jeopardy by the destruction of trees outside of forests and hedgerows. In order to acquire new insights in the impact of habitat fragmentation, I chose a species regarded as forest specialist and recognised as vulnerable to forest degradation, the Pine marten Martes martes, as a model. I studied habitat and corridor use by Pine martens by radio-tracking 24 martens in France on two different sites. The marten was shown as being a species not dependant on old growth forest, as was previously considered, but instead on the presence of trees in the close vicinity, be they forest groves or hedgerows
Plante, Sabrina, i Sabrina Plante. "Effets simples et cumulés des perturbations humaines sur l'utilisation de l'habitat et la survie du caribou migrateur". Doctoral thesis, Université Laval, 2020. http://hdl.handle.net/20.500.11794/38097.
Pełny tekst źródłaLes perturbations humaines sont en augmentation dans de nombreuses régions du monde et entraînent des conséquences graves sur les écosystèmes. Les régions nordiques et arctiques pourraient être particulièrement touchées par le développement anthropique à cause du fort potentiel en ressources naturelles et la faible résilience de ces écosystèmes. Le caribou migrateur (Rangifer tarandus) est au coeur de ces préoccupations puisqu’il constitue une espèce clé de cet écosystème. La majorité des troupeaux de caribous est toutefois en déclin et la nature généralisée et parfois synchrone de ces déclins suggère que des changements globaux, comme les changements climatiques et le développement anthropique, pourraient être responsables. Dans le nord du Québec et au Labrador, les caribous migrateurs des troupeaux Rivière-aux-Feuilles (TRAF) et Rivière-George (TRG) ne font pas exception à la tendance observée. Ces troupeaux ont subi une importante diminution au cours des dernières décennies. Simultanément à ces déclins, la région a connu une augmentation marquée des activités humaines, particulièrement dans le secteur minier. Toutefois, la contribution des perturbations humaines aux déclins de populations actuellement observés reste inconnue. Dans le cadre de cette thèse, je me suis intéressée à quantifier les effets des perturbations humaines sur l’utilisation de l’espace et la survie des caribous migrateurs du TRAF et TRG. Mes travaux sont divisés en quatre objectifs : 1) Évaluer les effets des perturbations humaines sur le comportement des caribous en évaluant l’impact des infrastructures linéaires sur les déplacements et en estimant les zones d’influence autour des infrastructures; 2) Évaluer la perte cumulée d’habitat associée à l’évitement des perturbations; 3) Évaluer l’effet des perturbations humaines sur la vulnérabilité des caribous à la chasse sportive; 4) Évaluer les effets des perturbations humaines sur le risque de mortalité des caribous et leur importance relative par rapport aux facteurs naturels; Mes travaux ont démontré que les caribous migrateurs répondent aux perturbations humaines à différentes échelles spatiotemporelles. À fine échelle, les caribous accéléraient leurs déplacements lors de la traversée d’une route. Une des routes sur l’aire de répartition du TRAF (route Raglan) semblait jouer un rôle de barrière aux mouvements des caribous. Les caribous évitaient les infrastructures sur des distances pouvant aller jusqu’à 23 km et l’évitement semblait exacerbé durant la période de chasse sportive. À plus large échelle, l’évitement des infrastructures s’est traduit en une perte cumulée d’habitat qui pouvait atteindre jusqu’à 30% des aires saisonnières et jusqu’à 37% des habitats fortement utilisés par les caribous. Mes travaux ont également démontré que la vulnérabilité des caribous à la chasse sportive était principalement affectée par les caractéristiques du paysage qui influencent la visibilité et l’accessibilité des chasseurs aux zones de chasse. Les caribous étaient plus vulnérables sur les lacs gelés, près des infrastructures de chasse, comme les pourvoiries et les routes, et dans les terrains moins accidentés. Ces résultats suggèrent que le développement anthropique pourrait augmenter l’accessibilité des chasseurs sur l’aire de répartition des caribous et donc augmenter leur vulnérabilité à la chasse. Finalement, mes travaux ont permis de démontrer que les perturbations humaines ont des effets négatifs limités sur le risque de mortalité des caribous. Leurs effets étaient typiquement moins forts que les facteurs naturels, tels que les patrons individuels d’utilisation de l’habitat, le risque de prédation et les conditions météorologiques, pour expliquer les variations du risque de mortalité des caribous. Ces résultats suggèrent que les impacts des perturbations humaines sur la survie des caribous sont limités, mais sont néanmoins présents. Le développement humain se poursuit dans les régions nordiques, ce qui pourrait rendre les caribous de plus en plus vulnérables aux impacts négatifs des perturbations humaines. Le niveau actuel de développement anthropique étant actuellement faible dans la région, il est possible de suggérer un changement dans l’élaboration et l’application de mesures de gestion pour les populations de caribou migrateur. Au lieu de tenter de mettre en place des mesures de gestion et de restauration coûteuses, il est encore possible aujourd’hui de restreindre le développement dans les zones critiques pour le caribou. Une approche proactive serait plus efficace afin de limiter les impacts négatifs sur la distribution et l’abondance des caribou. Les changements climatiques constituent une menace grandissante pour les populations de caribous, l’atténuation des impacts anthropiques pourrait donc augmenter la résilience des populations à ces changements globaux.
Human disturbances are increasing worldwide and have led to serious and irreversible consequences on natural ecosystems. Northern and Arctic regions may be particularly affected by anthropogenic development because of the high potential for the extraction of natural resources and the poor resilience of these ecosystems. Migratory caribou (Rangifer tarandus) are at the heart of these concerns raised by anthropogenic development in northern regions because they represent a key species of this ecosystem. Most caribou populations, however, are declining and the generalized and sometimes synchronous nature of these declines suggest that global changes, such as climate change and human development, may be responsible. In northern Québec and Labrador, Canada, migratory caribou of the Rivière-aux-Feuilles (RFH) and Rivière-George herds (RGH) are no exception to the current worldwide trend of decline. These herds have experienced an important decline in the last decades. Simultaneous to these declines, the region has experienced a rapid increase in human development, mainly owing to the mining sector. Yet, the contribution of human disturbance to the herds’ decline remains to be investigated. In this thesis, I assessed the effects of human disturbances on space use and survival of migratory caribou of the RFH and RGH. My work is divided into four objectives: 1) Evaluating human disturbance effects on caribou behavior, by evaluating the effect of linear features on caribou movements and by estimating the zones of influence of infrastructure; 2) Evaluating the cumulative habitat loss associated with the avoidance of infrastructure; 3) Evaluating human disturbance effects on caribou vulnerability to sport hunting; 4) Evaluating human disturbance effects on the mortality risk of caribou and their importance relative to that of natural factors. My results revealed that migratory caribou react to human disturbance at various spatiotemporal scales. At a fine scale, caribou increased their movement rate when crossing roads. One of the road in the Rivière-aux-Feuilles range (Raglan road) also appeared to act as a barrier to caribou movement. Caribou also avoided infrastructure over distances reaching as much as 23 km, and avoidance was exacerbated during the sport hunting period. At a larger scale, avoidance of infrastructures resulted in a cumulative habitat loss that could reach as much as 30% of the area of seasonal ranges, and 37% of high-quality habitat available for caribou. My work also revealed that caribou vulnerability to sport hunting was mainly affected by landscape characteristics influencing visibility and accessibility for sport hunters. Caribou were more vulnerable on frozen lakes, near hunting infrastructure such as roads and outfitter camps, and in less rugged terrain. These results suggest that human development could increase hunters’ accessibility to the landscape and thus, increase caribou vulnerability to sport hunting. Lastly, my work also showed that human disturbances have a limited impact on the mortality risk of caribou. These effects were typically less strong than natural factors, such as individual patterns of habitat use, predation risk and weather conditions, on caribou survival. These results suggest that the impacts of human disturbances are limited at the currently low state of development in northern Québec and Labrador, but are nevertheless observable. Anthropogenic development is continuing in northern regions, thus caribou could become increasingly vulnerable to the negative impacts of human disturbance. Because the current level of development in the RFH and RGH ranges is still low, it is appropriate to suggest a shift in the planning and implementation of management actions for population of migratory caribou. Instead of pursuing costly management and restoration activities after disturbance, it would be more effective to limit the area and intensity of development across the critical habitat of caribou. Such proactive approaches would be more efficient and effective at limiting declines in the distribution and abundance of caribou. Climate change is a growing threat for caribou populations; the mitigation of anthropogenic impacts could increase the resilience of these populations to global change.
Human disturbances are increasing worldwide and have led to serious and irreversible consequences on natural ecosystems. Northern and Arctic regions may be particularly affected by anthropogenic development because of the high potential for the extraction of natural resources and the poor resilience of these ecosystems. Migratory caribou (Rangifer tarandus) are at the heart of these concerns raised by anthropogenic development in northern regions because they represent a key species of this ecosystem. Most caribou populations, however, are declining and the generalized and sometimes synchronous nature of these declines suggest that global changes, such as climate change and human development, may be responsible. In northern Québec and Labrador, Canada, migratory caribou of the Rivière-aux-Feuilles (RFH) and Rivière-George herds (RGH) are no exception to the current worldwide trend of decline. These herds have experienced an important decline in the last decades. Simultaneous to these declines, the region has experienced a rapid increase in human development, mainly owing to the mining sector. Yet, the contribution of human disturbance to the herds’ decline remains to be investigated. In this thesis, I assessed the effects of human disturbances on space use and survival of migratory caribou of the RFH and RGH. My work is divided into four objectives: 1) Evaluating human disturbance effects on caribou behavior, by evaluating the effect of linear features on caribou movements and by estimating the zones of influence of infrastructure; 2) Evaluating the cumulative habitat loss associated with the avoidance of infrastructure; 3) Evaluating human disturbance effects on caribou vulnerability to sport hunting; 4) Evaluating human disturbance effects on the mortality risk of caribou and their importance relative to that of natural factors. My results revealed that migratory caribou react to human disturbance at various spatiotemporal scales. At a fine scale, caribou increased their movement rate when crossing roads. One of the road in the Rivière-aux-Feuilles range (Raglan road) also appeared to act as a barrier to caribou movement. Caribou also avoided infrastructure over distances reaching as much as 23 km, and avoidance was exacerbated during the sport hunting period. At a larger scale, avoidance of infrastructures resulted in a cumulative habitat loss that could reach as much as 30% of the area of seasonal ranges, and 37% of high-quality habitat available for caribou. My work also revealed that caribou vulnerability to sport hunting was mainly affected by landscape characteristics influencing visibility and accessibility for sport hunters. Caribou were more vulnerable on frozen lakes, near hunting infrastructure such as roads and outfitter camps, and in less rugged terrain. These results suggest that human development could increase hunters’ accessibility to the landscape and thus, increase caribou vulnerability to sport hunting. Lastly, my work also showed that human disturbances have a limited impact on the mortality risk of caribou. These effects were typically less strong than natural factors, such as individual patterns of habitat use, predation risk and weather conditions, on caribou survival. These results suggest that the impacts of human disturbances are limited at the currently low state of development in northern Québec and Labrador, but are nevertheless observable. Anthropogenic development is continuing in northern regions, thus caribou could become increasingly vulnerable to the negative impacts of human disturbance. Because the current level of development in the RFH and RGH ranges is still low, it is appropriate to suggest a shift in the planning and implementation of management actions for population of migratory caribou. Instead of pursuing costly management and restoration activities after disturbance, it would be more effective to limit the area and intensity of development across the critical habitat of caribou. Such proactive approaches would be more efficient and effective at limiting declines in the distribution and abundance of caribou. Climate change is a growing threat for caribou populations; the mitigation of anthropogenic impacts could increase the resilience of these populations to global change.
Znidi, Manel. "Habiter la grotte à Tataouine (sud tunisien) : de la maison creusée à la maison construite". Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0169/document.
Pełny tekst źródłaThe objective of this work is to contribute to the academic debate on the vernacular habitat. This multidisciplinary study combines three disciplines of architecture, anthropology and sociology to study the troglodyte habitat at Tataouine, a mountainous region in sourthen Tunisia at the edge of the Sahara.In this reseach work, we study the processus of mutations of this troglodyte habitat. The changes affect housing practices and lead to a new relationship with habitat. The reconstruction of the old theoretical writing on the corpus of study confronted with the results of the courses allows to rephrase the original characteristics of the troglodyte house and to take note of the current changes in this domestic architectural space.Rapid urbanization generates new configurations and new relationships between environments. The objective of our study is to know: to what extent has the phenomenon of urbanization of fected troglodyte habitat? What are the forms of readjustment adapted by the population to deal with changes in lifestyles? Today, only the two villages of Chenini and Douiret are still inhabited. The morphology of the evolution in tie and in space of troglodyte habitat in these two villages should be examined. What are the new ways of living? What are the new forms of construction? To what extent is the cave still used?
Gervais, Amélie. "De la communauté à l’individu : influence de l’intensité agricole et du paysage sur les bourdons (Bombus spp.) du Sud du Québec". Doctoral thesis, Université Laval, 2020. http://hdl.handle.net/20.500.11794/66288.
Pełny tekst źródłaPollinators are essential to natural ecosystems and crop production. However, they are in decline and many causes are possible: climate changes, diseases, parasites, loss of natural habitats, loss of floral resources, landscape homogenization and agricultural intensification. In southern Québec, a west-east gradient, from intensively managed landscapes in the west to a more extensive production in the east is present. In this context, it is quite interesting to see how pollinators, such as bumble bees, cope with such an important agricultural gradient. To test the importance of agricultural landscape composition on bumble bees, we investigated three different levels of organization: 1) individual, 2) colonies and 3) communities. To evaluate the impact of the landscape on the individuals and colonies levels, we placed 80 colonies of Bombus impatiens on 20 different sites in the gradient during the spring and summer of 2016. Landscapes were characterized within 1 km from the colonies using orthophotos and the landscape components were categorized following: intensive crops, extensive crops, flowering crops, forests, urban areas and aquatic environment (lakes, rivers). Each week, we counted the number of workers entering and exiting colonies and a total of four workers per colony were captured, measured and had their pollen load identified. Worker size was not influenced by the landscape. However, their foraging behavior seemed affected since the ins and outs of workers dropped in more intensive landscape. Furthermore, pollen species collected by workers were different in more intensive landscapes compared to those of more extensive landscapes. For the colony level, each one had its weight taken every week and at its death, its final weight, the number of queens produced and the presence of Aphomia sociella were noted. Colonies placed in the landscape with a high proportion of intensive crops gained less weight and lived almost two weeks less than colonies in more extensive landscape. The proportion of flowering crops in the landscape had the opposite effect by increasing both the weight and the life expectancy of colonies. The number of queens produced and the probability of being predated by A. sociella were not linked to landscape composition. At the community level, another study took place from 2006 to 2016 on 40 farms from the same agricultural gradient. A total of 4726 bumble bee queens were captured using yellow window traps. The landscape was described again using orthophotos and the same categories, but at a 500 m radius instead. The proportions of intensive and flowering crops as well as the proportions of forests each influenced the abundance and occurrence of some species, but they were not the most important variables explaining the bumble bee community structure. The functional traits were, in fact, more important to explain the abundance of species, where smaller and underground nesters species were more abundant, in all the landscapes. The results presented in this thesis bring even more evidence that landscape has an important impact on bumble bees at every level. Furthermore, we highlight once more that intensive cropping systems are truly detrimental to bumble bee persistence in agroecosystems.
Houde, Nicolas. "La manipulation des ressources alimentaires et du risque de prédation afin d'augmenter la vulnérabilité du cerf de Virginie à la chasse". Master's thesis, Université Laval, 2016. http://hdl.handle.net/20.500.11794/27089.
Pełny tekst źródłaA trade-off between forage acquisition and predation avoidance often drives space use by prey herbivores. We tested the effects of manipulating forage production and residual forest cover on white-tailed deer (Odocoileus virginianus) space use and vulnerability to hunting on Anticosti Island. Our results demonstrated that deer space use and deer vulnerability to hunting could be modified by different structural components of the habitat. Forage productivity led to higher deer use of managed habitats, whereas decreased residual forest cover increased deer vulnerability to hunting. These results provide useful insights for wildlife managers who have to deal with conflicting goals such as maintaining hunter satisfaction with increased observations of deer while reducing deer densities which are undesirable in many economic and ecological aspects.
Rioux, Jérôme. "Effets de la coupe avec la protection des petites tiges marchandes (CPPTM) et de la coupe avec la protection de la haute régénération et des sols (CPHRS) sur la faune de la pessière noire à mousses de l'Est". Thesis, Université Laval, 2006. http://www.theses.ulaval.ca/2006/24072/24072.pdf.
Pełny tekst źródłaHuillet, Laetitia. "Tendances spatio-temporelles de répartition chez les oiseaux hivernants durant 26 ans d'étalement urbain à Québec". Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24161/24161.pdf.
Pełny tekst źródłaQuébec City, along with other North American cities, has experienced a very rapid growth in area in the last three decades. We assessed the consequences of urban sprawl on wintering bird trends by determining, among 29 wintering species, those whose trends were correlated to habitat change resulting from urban sprawl. We used data from Christmas Bird Counts (CBC) of Québec City and a series of aerial photos taken between 1978-2003. The Québec Christmas Bird Count territory (a 460 km² circle) is divided in 75 census plots. In order to study land use trends of these plots we scanned and georeferenced 6 series of aerial photos taken between 1978 and 2003 and measured “Green” (parks, residential zones, etc.) and “Grey” (industrial, commercial, etc.) urban areas, agricultural lands, fallow lands and forest patches. We proceeded in two steps. First, we calculated a specific habitat area index for each census plot, species, and year of the study (this habitat index took into account species associations to each land use). Then we measured the relationship between population trends and corresponding habitat change for 1) all the species and 2) individual species. Most species were associated to « green » urban areas and avoided agricultural areas. A large number of species showed a significant habitat gain. Species that had the highest habitat gains showed the highest increase in their population trends. Population trends for at least seven species were strongly associated with local habitat change. However, in most species, association explained by urban sprawl per se is not clear, numerous factors could play a major role in population trends.
Devoucoux, Pierrick. "Conséquences et impacts prévisibles d'une perte d'habitat majeure sur une espèce menacée aux exigences écologiques complexes : effets de la mise en place du contournement ferroviaire à grande vitesse Nîmes-Montpellier sur la dynamique de la population d'Outarde canepetière des Costières de Nîmes". Thesis, Poitiers, 2014. http://www.theses.fr/2014POIT2285/document.
Pełny tekst źródłaUrbanization and increasing transport infrastructure construction are known as the main cause of biodiversity loss. By habitat loss and landscape fragmentation they cause, these structures impact populations. Our work sought to assess, on a case of complex ecological requirements, foreseeable impacts of the establishment of a High Speed Line (HSL) and their consequences. We studied the population of Little Bustard Tetrax Tetrax of the Costières nîmoise area. Within its own range scale, this population is an exception: it reaches locally unusually high densities and develops distributions patterns never met previously. We sought to identify local variations in distribution and their correlation with habitat parameters in a wide range of spatial scales, to model the expected distribution patterns and expected impacts of future infrastructure
Montuire, Sophie. "Communautés de mammifères et environnements : l'apport des faunes aux reconstitutions des milieux en Europe depuis le Pliocène et l'impact des changements climatiques sur la diversité". Montpellier 2, 1994. http://www.theses.fr/1994MON20214.
Pełny tekst źródłaHadley, Adam. "Winter habitat use by Boreal Chickadee flocks within a managed forest landscape". Thesis, Université Laval, 2006. http://www.theses.ulaval.ca/2006/23847/23847.pdf.
Pełny tekst źródłaResident bird species inhabiting northern latitudes are considered to be the species most exposed to the effects of habitat loss and fragmentation of boreal forests. Despite the fact that their population dynamics appear to be strongly determined by events occurring during the non-breeding season, we have little knowledge of the winter ecology of boreal birds. My objective was to determine how increasing edge densities and reducing the proportion of mature boreal forest will affect a resident bird species. I recorded movements of 85 unmarked and seven colour banded winter flocks of the little-known Boreal Chickadee (Poecile hudsonica), in a 66 km2 boreal forest harvested for timber near Quebec City, Quebec, Canada. From January-March (2004 and 2005), I followed flocks on snowshoes and recorded their paths in real time using a handheld GPS receiver. Using marked individuals, I found winter Boreal Chickadee flocks included an average of 4 individuals, occupied a mean winter home range of 14.7 ha and showed stable membership. Based on 74 km of flock movements, Boreal Chickadees strongly preferred mature forest (>7 m in height), used regenerating forest (4-7 m) to a lesser extent and avoided younger stands (<4 m) and open areas. Chickadee flocks showed no response to forest edges when using mature forest stands. However, inside regenerating forest, flocks were significantly closer to both open edges (41 ± 6 m) and mature forest boundaries (11 ± 2 m) than would be expected from random use of the habitat. Boreal Chickadee flocks did not avoid exposed edges during harsh weather conditions. In fact, on colder days, they were found disproportionately more often along edges between mature and regenerating stands. Increasing edge densities, resulting from clearcutting in boreal forest, does not necessarily reduce the winter suitability of remaining forest patches, even under inclement weather. However, I conclude that forest harvesting will result in a reduction of optimal wintering habitat for this species.
Bennour, Myriam. "La patrimonialisation des arbres urbains : le cas de Tunis". Thesis, Paris, AgroParisTech, 2014. http://www.theses.fr/2014AGPT0079.
Pełny tekst źródłaThis thesis is part of a geographical and anthropological field. It analyzes historic and contemporary relationships between Tunisians and trees in the city. Taking as a case study the city of Tunis, it aims to show that there is, from the beginning of colonization, among Tunisians a complex process of appropriation but also rejection of trees depending on their public or private location, and their personal history.Multiple values are indeed associated with trees. Analysis of the interviews shows that these values are based primarily on individual memory, family practices and social memory. Before colonization, the Medina had few trees in public space because the spatial organization drew its roots from the traditional settlement pattern, which did little or no appeal to trees in private patios. In addition, the traditional urban law did not use trees in public space. Upon initiation of the French Protectorate, the capital has been extended beyond the walls with the city called European. Large avenues and streets were lined up with rows of trees. New species were then widely introduced and disseminated, modeled on the French cities of that time.After independence, the capital swelled by the spread of rural migration, wealthy Tunisians lived in new neighborhoods that combined European style and Tunisian traditions (especially in the north). Rural Tunisians in search of a better life have occupied smaller areas (west and south). The capital has become a socially heterogeneous space marked by abundance and different types of trees in public and private spaces of the various neighborhoods.This thesis is a first step in the interpretation of urban living from recent history, marked by the functional, symbolic and aesthetic uses of trees. It shows that today the trees in Tunis are or become social, individual and collective markers that define different types of heritage; private, collective and public. This heritage process is not necessarily tied to an institutional setting
Beardsell, Andréanne. "Écologie de la nidification de la buse pattue dans le Haut-Arctique et vulnérabilité des nids aux risques géomorphologiques". Master's thesis, Université Laval, 2016. http://hdl.handle.net/20.500.11794/26921.
Pełny tekst źródłaThe physical characteristics of a nest site are thought to influence both its use by birds and the outcome of breeding attempts. The rough-legged hawk (Buteo lagopus) built a massive nest, which can be reused several years, along cliffs and slopes in the Arctic. These steep habitats are exposed to mass movements which may result in the destruction of critical sites for hawks. We examined the relationships between several environmental variables, patterns of nest reuse and reproductive output in rough-legged hawks. We also assessed nest vulnerability to mass movements and identified environmental factors associated with the persistence of nesting structures. The study was conducted on Bylot Island (Nunavut) from 2007 to 2015. Nest use probability increased with the nearest distance to breeding conspecific, with lemming density and for sheltered nest. Hawk nests inaccessible to foxes and facing away from the north were associated with a high reproductive success. Reproductive success was also positively related to summer lemming density and negatively related to rainfall. Our results suggest that nest site physical characteristics offering a favorable microclimate and protection from weather and predators provide the highest-quality site. Hawks that bred in a newly-built nest had similar success compared to those that used pre-existing nests, suggesting that building a new nest entailed no short term reproductive costs. Among 82 known nests, nearly a third were destroyed during the study and among those still intact, more than half are exposed to a moderate to high risk of being destroyed. The probability of nest destruction was high for nests built on unconsolidated sediments and positively associated with heavy rainfall. The anticipated increase in precipitation due to climate change is likely to increase the exposure of nest to mass movements which could ultimately reduce the availability of suitable sites for the reproduction of this raptor.
Lozach, Sophie. "Habitats benthiques marins du bassin oriental de la Manche : enjeux écologiques dans le contexte d’extraction de granulats marins". Thesis, Lille 1, 2011. http://www.theses.fr/2011LIL10163/document.
Pełny tekst źródłaThe natural variation in the coarse sediment benthic community was investigated over a four-year period in the context of an aggregate extraction licence project in the eastern Channel paleovalleys deposits. Six surveys were conducted: twice a year (mid-April: pre- recruitment and the end of August: post-recruitment) in 2007, 2009 and 2010. The data set obtained shows on one hand that the coarse sediment of the benthic community of the eastern English Channel paleovalleys presents an outstanding constancy over time and on another hand, it brings out new pieces of knowledge on benthic habitats typology in offshore coarse sediments (EUNIS). A complementary study on functional features showed that this benthic community has a high resistance to physical disturbance, but lower resilience. This knowledge on benthic community structure and functioning allowed the making of assumptions on the consequences of marine aggregate extraction at this site. An adaptive management of this human activity has then been proposed by the implementation of a benthic monitoring responding to ecological issues associated with marine sediment dredging. Results obtained during this study will also be a substantial input to scientific understanding of dredging impacts should the licence be delivered by French authorities
Cateau, Eugénie. "Réponse des coléoptères saproxyliques aptères aux perturbations anthropiques des forêts et des paysages". Thesis, Toulouse, INPT, 2016. http://www.theses.fr/2016INPT0045/document.
Pełny tekst źródłaTo enable species migration in a global warming context, public policies try to improve European natural network (Green and Blue infrastructure, old trees network...). These measures might be adapted to the high-dispersal species, but there is a lack of knowledge concerning the ability of the low-dispersal species to move using these networks. Lots of these species remain poorly known. Considering forest ecosystems, ightless saproxylic beetles are supposed to be dispersal limited species because of they are small, unable to y and have trophic exigencies. The aim of this study is to understand how dispersal limited species evolve temporally and spatially in the landscape. Flightless saproxylic beetles have been sampled by sieving litter in front of ten trees per stand, using a modied Winkler and extracted through an adapted Berlese. This standardization of the methods lead to sample an average of 97,2% of the species targeted in each forest. A monthly survey during two years has shown that the species are present in the litter throughout the year and that they are stable over two years. The best season to sample them appeared to be autumn and spring. Comparison between old growth forests and harvested stands in the French Pyrénnées has shown that harvesting does not impact signi cantly the target species. Their repartitions were highly dierent between the studied valleys, which is assumed to result from the dierence in the past human impact. In the highly fragmented landscape (Coteaux de Gascogne, SW France), very few ightless saproxylic species have been sampled. Surprisingly, this experiment has shown that the landscape characteristics explain better these dispersal limited species' repartitions than the forest characteristics. For half of them, landscape composition in the 1850's explain better the repartition than the current one. A threshold of 15% of forest cover appeared to be determinant for one species (Dienerella clathrata). We showed that the studied species use the edges (at least to move through them) whatever their characteristics may be. As soon as they are present in the forest, they are in the connected edge. Moving abilities of 3 species have been approached by measuring the running speed in laboratory. This experiment showed a mean of running speed of 1,6m.h -1. These dierent elements lead us to conclude that the ightless saproxylic beetles are mobile in the landscape. All these results, and the fact that species richness is correlated to the landscape anthropisation, leads us to conclude that this taxonomic group can support human impact at small spatial and temporal scale, but are poorly resilient to large and long anthropisation
Mercader, Manon. "Rôle des infrastructures portuaires dans le maintien des populations de poissons côtiers : apports de la restauration écologique". Thesis, Perpignan, 2018. http://www.theses.fr/2018PERP0027/document.
Pełny tekst źródłaHabitat loss caused by urban sprawl has harmful consequences on marine biodiversity. With a view to maintaining biodiversity and fish stocks, it may be worthwhile to restore some ecological features in anthropized areas. The aim of this thesis was to estimate the potential role of ports as habitat for juvenile coastal fish and to evaluate how this role can be improvedthrough restoration actions. Tank experiments revealed that juvenile survival rate on artificial habitats used for restoration purpose could be equivalent to that observed on natural habitat. The assessment of the spatial distribution of juvenile at the scale of a seascape permitted to estimate that harbors could host densities of juvenile that were between 50 to 90% of thoseobserved in natural sites. Within harbors densities were highly dependent on the type of habitat, featureless dock hosting the lowest densities. Subsequently, based on case studies, this work demonstrated that harbors rehabilitation could significantly enhance juvenile densities at the habitat scale. Densities on restored habitat might reach those observed in natural habitats.However, at the scale of the whole harbor benefits were low. This work suggests that harbors have a real potential as an alternative juvenile habitat, especially if restoration actions are undergone. However, for more efficiency, restoration projects should be led at the scale of the whole site and include a diversity of artificial habitats. Thereby, restoration approaches shouldbe considered as a complementary tool to protection measures in a seascape integrated management approach of coastal areas
Bouchoucha, Marc. "Les zones portuaires peuvent-elles servir de nourriceries alternatives pour les poissons marins côtiers ? : cas des sars en Méditerranée Nord-occidentale". Thesis, Perpignan, 2017. http://www.theses.fr/2017PERP0046/document.
Pełny tekst źródłaDuring their life cycle, most of the marine coastal fish species use nursery grounds which quality influence their recruitment and then the conservation of their populations. However, the construction of ports impair irremediably fish nursery function of the coastal areas impacted. The ultimate aim of the PhD research was to assess if ports could provide suitable alternative nursery habitats for coastal fish species. Firstly, abundances of the juveniles of four Diplodus species were surveyed in five marinas located along the French Mediterranean coast. This showed that coastal fishes can successfully settle and grow inside these artificialized coastal areas. Moreover, increasing the complexity of port habitats can considerably enhance their suitability for juveniles, especially at the youngest stages. Secondly, body condition, growth rate and metal contamination in the juveniles of two Diplodus species (D. sargus and D. vulgaris) were compared between different ports and natural areas in the Bay of Toulon. Juvenile growth and condition can be equivalent between fish collected from ports and from adjacent natural areas. Contamination levels in fish were low, even in highly polluted areas. Finally, otolith composition in the juveniles of D. sargus and D. vulgaris was investigated in three ports and two natural areas in the Bay of Toulon. None of the port related had systematically higher concentrations in otoliths from Diplodus juveniles collected in ports. Therefore, otolith microchemistry cannot provide a unique and reliable fingerprint discriminating ports and natural areas. Nevertheless, otolith microchemistry could provide an effective natural tag to determine the contribution of ports to adult stocks provided that a library of all potential juvenile habitat fingerprints is established. All these results confirm that ports can be used as alternative nursery habitats by marine coastal fishes. Ecological engineering projects aiming at increasing structural complexity of port habitats seem promising for biodiversity and fish stock conservation
Padié, Sophie. "Réponse des cervidés à la chasse : stratégies d’utilisation de l’espace à multiples échelles et conséquences sur la végétation". Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20185.
Pełny tekst źródłaHunting – similarly to natural predation – induces behavioural responses of hunted individuals which aims at avoiding or reducing risk. Particularly, changes in space use are frequently observed, but the articulation and determinants of these changes at multiple spatial scales are still poorly understood. Also, although it has been suggested that these changes might cascade on the vegetation, this remains to be tested. To fill these gaps, I (1) studied a hunted roe deer population living in an agricultural landscape in southern France where roe deer can find open risky habitats and woody covers; and (2) tested black-tailed deer behavioural response to an experimental hunt in a predator- and hunting-free population in the Haïda-Gwaii archipelago (BC, Canada). I also investigated the possible cascading effects on the vegetation. I showed that roe deer responded to increased hunting pressure at multiple scales, reducing their use of the risky habitats and, in specific situations, their distance to the nearest cover. At day-time those two responses were coupled at the individual level. Generally, landscape openness constrained individual responses and strategies. In the hunting-for-fear experiment conducted on Haida Gwaii, I found that only the deer less-tolerant to human disturbance avoided the hunting area. A simultaneous reduction in browsing pressure on two out of the four plant species monitored was found however. I integrated these results in a general discussion on the possible role of hunting as a tool to manage abundant deer populations and their impacts on the vegetation
Tourenq, Christophe. "Valeurs et fonctions des rizières pour les communautés d'oiseaux d'eau en Camargue". Montpellier 2, 2000. http://www.theses.fr/2000MON20206.
Pełny tekst źródłaGagné, Nancy. "Comparison of the effects on small mammals of regeneration methods in the boreal balsam fir forest = (Comparaison des effets sur les petits mammifères des méthodes de régénération de la sapinière boréale) /". 1997. http://proquest.umi.com/pqdweb?did=737015801&sid=9&Fmt=2&clientId=9268&RQT=309&VName=PQD.
Pełny tekst źródłaBujold, Frédéric. "Impacts de l'éclaircie précommerciale sur le lièvre d'Amérique dans la sapinière à bouleau blanc de l'Est /". 2004. http://proquest.umi.com/pqdweb?did=845761621&sid=4&Fmt=2&clientId=9268&RQT=309&VName=PQD.
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