Tesis sobre el tema "Plantes des tourbières"
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Leroy, Fabien. "Effets des changements de végétation dans les tourbières à sphaignes sur le cycle du carbone". Thesis, Orléans, 2017. http://www.theses.fr/2017ORLE2029/document.
Peatlands have stored a third of the soil organic Carbon (C) in only 3% of the land area. However, in response to global change, boreal and temperate peatlands may shift from Sphagnum to vascular plant-dominated peatlands that may alter their C-sink function. This thesis aims at providing a better understanding of the vascular plants interactions in a Sphagnum dominated peatland and their implications on the C cycle. This work mainly focus on the invasion of a graminoid plant, Molinia caerulea, through a mesocosm experiment. Results from experiments show that vascular plants are both able to promote the growth of Sphagnum mosses as well as the decomposition of their litter. Molinia caerulea occurrence appears to increase the C sink capacity of Sphagnum peat mesocosms passing of 30 to 220 gC stock m⁻² y⁻1. This capacity of Molinia caerulea to store C is probably due to it high roots productivity. However, it also seems to stimulate the decomposition of ‘old’ C, stored as peat, by stimulating microorganisms activity through roots exudates. These latter also promote the dissolved organic C consumption and CO₂ and CH₄ emissions observed with Molinia caerulea occurrence, as well as the temperature sensitivity of C exports by altering the microbial communities. Molinia caerulea impacts on microorganisms also affect N cycle conducting to a decrease of N₂O emissions in these ecosystems
Kebaili, Caroline. "Impact de l'homme et du climat sur l'histoire démographique de 4 espèces emblématiques de papillons des tourbières de Franche Comté, et implications pour la gestion conservatoire". Electronic Thesis or Diss., Université Grenoble Alpes, 2023. http://www.theses.fr/2023GRALV111.
L’intérêt démontré de l’utilisation conjointe de données génétiques et écologiques pour analyser la connectivité, issue de la proche collaboration entre la recherche et le terrain, illustre la complémentarité de la modélisation et du suivi de terrain pour la conservation de la biodiversité.The erosion of biodiversity is a major issue of the 21st century. The massive loss of species over the past decades has profoundly disrupted ecosystems and compromised the multiple services they provide to human societies. Among the main factors of this erosion are global warming and the degradation or destruction of habitats due to anthropogenic activities. This last factor contributes to increase habitat fragmentation and is deleterious to landscape connectivity. However, it is essential for maintaining species with limited dispersal capacities and/or living in metapopulations.Landscape connectivity is one of the main concerns of managers of natural environments. This is the case for four species of peta bogs butterflies from Jura (the Cranberry fritillary Boloria aquilonaris, the Large heath Coenonympha tullia, the Violet copper Lycaena helle and the Scarce heath Coenonympha hero) which, despite numerous conservation efforts and the protection of their habitat through a LIFE program, still show signs of decline and are included on the French and Franche-Comté IUCN red lists.The objectives of this thesis were (i) to study the population genetic structure and diversity of these species in the Jura massif and to highlight the elements of their post-glacial demographic history which may have contributed to this structuring, (ii) to establish a methodology to model the complex mosaic of environments that make up the landscape in which species live, and (iii) to model the landscape connectivity of species in order to guide future management measures.Genetic analysis revealed variable conservation states for the four species, showing a worrying situation for C. tullia and B. aquilonaris and rather stable for L. helle and C. hero. The demographic history is common and reveals a post-glacial recolonization of the Jura massif from the North. The comparison of genetic and landscape graphs has proven effective in parameterizing complex landscape resistance surfaces and its results have been used to model connectivity, in association with expert ecological data. An area of high conservation concern, located in the center of the massif, has been identified for L. helle, C. tullia and B. aquilonaris, as well as an apparent disconnection with the other regions of the massif, at least for the last two species.The demonstrated interest in the joint use of genetic and ecological data to analyze connectivity, resulting from close collaboration between research and the field, illustrates the complementarity of modeling and field monitoring for the conservation of biodiversity
Comont, Laure. "Étude des processus de stockage de la matière organique et de régénération des tourbières dégradées après exploitation : sites du Russey (Jura français), de la Chaux d’Abel (Jura suisse) et de Baupte (Cotentin, France)". Orléans, 2006. http://www.theses.fr/2006ORLE2047.
Gicquel, Aurélien. "Impact des changements globaux sur le fonctionnement des tourbières : couplage C-N-S et interactions biotiques". Rennes 1, 2012. https://ecm.univ-rennes1.fr/nuxeo/site/esupversions/fc809707-f62e-4b7b-aaa0-3ce961750dde.
In a context of global change, peatlands "sink" function of carbon (C) is likely to switch to a "source" function, releasing into the atmosphere large quantities of C initially stored in the peat. This thesis aims to characterize and quantify at different levels of organization: i) the impact of global warming on Sphagnum-peatland biogeochemical functioning (CNS) and ii) the impact of restoration of peatland abandoned after harvesting of peat on the interactions between recolonizing plants (Eriophorum angustifolium), macrofauna (Lumbricus rubellus) and the microorganisms potentially involved in the regeneration process of peat forming. The peatland functioning and biotic interactions have been studied by coupling C-N-S and isotope tracing 13C-15N-34S. A moderate increase of + 1°C simulated by "Open Top Chambers" (OTCs) significantly reduces C fluxes at the ecosystem level, the primary production of Sphagnum and the microbes are most affected. At the community level, the activity of anaerobic bacteria, fungi and protozoa (estimated by SIP 13C-PLFAs) was significantly slowed. We showed that a soil engineer as the earthworm L. Rubellus played a positive role in recycling organic matter indirectly by providing elements (C > N > S) to the plant. Transfers depend on the functional traits of the organism. At the individual level, we have characterized using NanoSIMS, "anticorrelated" NS transfers from earthworms to peat
Messier, François. "Évaluation de méthodes de lutte aux plantes envahissantes en tourbière: les cas de la quenouille et du roseau". Master's thesis, Université Laval, 2017. http://hdl.handle.net/20.500.11794/27764.
Broad-leaf cattail (Typha latifolia, a native plant in North America) and common reed (Phragmites australis, haplotype M, the exotic Eurasian genotype) are often observed in Sphagnum-dominated peatlands once peat extraction activities have ceased. Both species are tall opportunistic herbs showing highly competitive behavior through vegetative propagation and seed production. They are invasive in peatlands that have been used for peat extraction and could become a major threat to restoration projects by preventing the establishment of desirable plant species and potentially reducing carbon sequestration. Furthermore, seed dispersal could contaminate adjacent commercial peat fields. Dense, nearly monospecific, patches of Cattail and Reed have been recently identified in two bogs located in eastern Canada cutover bogs. The main objective of this project was to evaluate and test methods to prevent the spread of these invasive plants in peatlands. Different control methods, such as repeated stem cutting, tarping and revegetation were tested on cattails and reeds, at Bois-des-Bel (BDB, a restored peatland) and Saint-Alexandre-de-Kamouraska (SAK, an unrestored site). Repeated cuttings (3 times per summer) decreased cattail stem density by 77 % and biomass by 88 % compared to control (no cutting) sites. Field observations suggest that a combination of tarping and planting willows to rapidly establish a dense plant cover could inhibit the regrowth of reeds. This project examines a new aspect of biological invasions in North American peatlands. It contributes to the development of technical and operational expertise regarding invasive plant control, based on experimental evidence. Key words: Broad-leaf cattail, Typha latifolia, common reed, Phragmites australis, peatlands, bog, invasion, control
Fay, Emmanuelle. "La dynamique et l'impact du bouleau envahisseur dans une tourbière de l'Est du Canada". Thesis, Université Laval, 2006. http://www.theses.ulaval.ca/2006/23632/23632.pdf.
Bugnon, Jean-Luc. "Perspectives de restauration des tourbières dans l'est du Québec, réintroduction des sphaignes sur des tourbières extrêmement sèches ayant été exploitées par aspiration et abandonnées et, effets de la présence des plantes vasculaires sur la croissance des sphaignes, sur d'anciens sites d'exploitation de la tourbe par la coupe de blocs". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/mq25519.pdf.
Gicquel, Aurélien. "Impact des changements globaux sur le fonctionnement des tourbières : couplage C-N-S et interactions biotiques". Phd thesis, Université Rennes 1, 2012. http://tel.archives-ouvertes.fr/tel-00734604.
Sall, Papa Malick y Papa Malick Sall. "Phyto-aménagement de tourbières résiduelles : effet du chaulage et de la fertilisation sur la croissance du saule et de l'alpiste roseau et sur la répartition chimique de métaux lourds dans les sols et les plantes". Doctoral thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/31466.
L’objectif général de l’étude est de valoriser deux sites de tourbières résiduelles situés à Lamèque et à La Mousse Acadienne (Nouveau-Brunswick, Canada) pour la production de deux plantes à valeur énergétique, le saule (Salix miyabeana) et l’alpiste roseau (Phalaris arundinacea). Cette réhabilitation est nommée «phyto-aménagement». Par ailleurs, dans un contexte de changements climatiques et d’épuisement des énergies fossiles, le phytoaménagement à base de plantes bioénergétiques présente un intérêt avec l'utilisation de la biomasse agroforestière comme combustible à moindre émission dans les chaudières à biomasse. Les résultats des essais menés en serre sur le sol de la tourbière résiduelle du site Sun Gro indiquent que les doses croissantes de chaux calcique en présence d’une dose d’engrais NPK, ainsi que les doses croissantes d’engrais en présence d’une dose de chaux dolomitique ont un effet significatif sur les paramètres de croissance et de rendements du saule, certaines propriétés édaphiques dont le pH, et les teneurs des métaux Cu, Fe, Mn et Zn sous formes facilement labiles et moyennement labiles dans le sol. Une fraction importante de Cu est liée à la matière organique du sol. Les métaux Fe, Mn et Zn se retrouvent majoritairement fixés par les oxydes du sol. Les essais à petite échelle de saule et d’alpiste roseau cultivés dans les tourbières résiduelles du site La Mousse Acadienne indiquent que ces deux plantes répondent bien à la fertilisation minérale en présence de la chaux dolomitique. En favorisant le développement de la plante, l’apport de l’engrais (NPK) favorise la production de biomasses aériennes ainsi que le prélèvement des cations nutritifs. Les parcelles de saules fertilisées ont fourni un rendement maximum de 6161,6 kg/ha en 16 mois de croissance au moment où les parcelles non fertilisées ont assuré un rendement maximum de 437,0 kg/ha. D’une manière générale, les concentrations des métaux Ca, Mg et Mn sont retrouvées majoritairement dans les parties aériennes des plantes tandis que celles des métaux Al, Cd, Cu, Fe, et Zn sont plus élevées dans les racines. Les concentrations des éléments traces métalliques dans les parties aériennes des plantes sont en deçà des valeurs seuils de toxicité. Les résultats révèlent que le pH du sol est une propriété chimique clé à considérer lors du phyto-aménagement des tourbières résiduelles acides.
The mechanical exploitation of the natural peat bogs produces media called "residual peat bogs" among which the physico-chemical properties, naturally constraining, are degraded. The objective of this study was to evaluate the potential productivity of two energy crops, willow (Salix miyabeana) and the reed canary grass (Phalaris arundinacea), on residual peat bogs situated at Lamèque in New Brunswick (Canada). This type of rehabilitation is named "phyto-management". Moreover, in the climate change context and the depletion of fossil fuels, bioenergy-based phytomanagement is of interest with the use of agroforestry biomass as a lower emission fuel in biomass boilers. The results of glasshouse study conducted on RPB from the site Sun Gro indicated that N-P-K fertilizer and calcitic or dolomitic lime applications have a significant effect on growth and yield parameters of willow as well as on certain edaphic properties such as pH and the content of metallic trace elements (Cu, Fe, Mn, Zn) in the labile and moderately labile fractions. Organic matter matrix is an important binding site for Cu whereas oxide matrix for Fe, Mn and Zn. The small-scale field trials conducted at the Mousse Cannadienne site highlighted that willow and reed canary grass can be grown in the residual peat bogs amended with dolomitic lime and fertlized with complete fertlizer. Fertilizer containing the chemical elements improves growth, uptake of cationic nutrients and productiveness of plants. The fertilized and limed willow plots produced a maximum yield up to 6161.6 kg / ha in 16 months of growth. The limed plots without fertilizer produced 437,0 kg shoot biomass of willow / ha. Generally, the highest concentration of Ca, Mg and Mn is mainly found in the aerial parts of plants whereas those of Al, Cd, Cu, Fe, and Zn are highest in roots. The concentrations of metallic trace elements in shoot plant biomass are below thresholds values of toxicity. The results reveal that the soil pH is a key chemical property to be considered during the phyto-management of acid residual peat bogs.
The mechanical exploitation of the natural peat bogs produces media called "residual peat bogs" among which the physico-chemical properties, naturally constraining, are degraded. The objective of this study was to evaluate the potential productivity of two energy crops, willow (Salix miyabeana) and the reed canary grass (Phalaris arundinacea), on residual peat bogs situated at Lamèque in New Brunswick (Canada). This type of rehabilitation is named "phyto-management". Moreover, in the climate change context and the depletion of fossil fuels, bioenergy-based phytomanagement is of interest with the use of agroforestry biomass as a lower emission fuel in biomass boilers. The results of glasshouse study conducted on RPB from the site Sun Gro indicated that N-P-K fertilizer and calcitic or dolomitic lime applications have a significant effect on growth and yield parameters of willow as well as on certain edaphic properties such as pH and the content of metallic trace elements (Cu, Fe, Mn, Zn) in the labile and moderately labile fractions. Organic matter matrix is an important binding site for Cu whereas oxide matrix for Fe, Mn and Zn. The small-scale field trials conducted at the Mousse Cannadienne site highlighted that willow and reed canary grass can be grown in the residual peat bogs amended with dolomitic lime and fertlized with complete fertlizer. Fertilizer containing the chemical elements improves growth, uptake of cationic nutrients and productiveness of plants. The fertilized and limed willow plots produced a maximum yield up to 6161.6 kg / ha in 16 months of growth. The limed plots without fertilizer produced 437,0 kg shoot biomass of willow / ha. Generally, the highest concentration of Ca, Mg and Mn is mainly found in the aerial parts of plants whereas those of Al, Cd, Cu, Fe, and Zn are highest in roots. The concentrations of metallic trace elements in shoot plant biomass are below thresholds values of toxicity. The results reveal that the soil pH is a key chemical property to be considered during the phyto-management of acid residual peat bogs.
Paitre, Cédric. "Dynamique des marges forestières de milieux tourbeux du Haut-Boréal, Québec nordique". Thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25503/25503.pdf.
Caisse, Gabriel. "Importance de la fertilisation lors du boisement des tourbières résiduelles". Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24833/24833.pdf.
Kuentz, Adèle. "Dynamiques actuelle et holocène de la Puna (Andes sèches du Pérou) à partir des observations de terrain, de la cartographie (SIG) et de la palynologie (Région du Nevado Coropuna)". Clermont-Ferrand 2, 2009. http://www.theses.fr/2009CLF20013.
Muller, Serge. "La végétation du Pays de Bitche (Vosges du Nord) : analyse phytosociologique : application à l'étude synchronique des successions végétales". Paris 11, 1986. http://www.theses.fr/1986PA112076.
This thesis consists in a phytosociological and phytodynamical study of an area on sanstone in the North-East of France. The vegetation has been studied according to the principles of the "sigmatist" method, by using numerical analysis to recognize the plant communities. 19 associations, corresponding to forests, outskirts, heaths, sandy lawns, initial stages and peat bogs are described on the floristical and phytosociological level. Their ecological and chorological features are precised and these communities are compared to their equivalents of Eastern and Central Europe. The different plant successions and series, primary and secondary, progressive and regressive, are then defined by synchronical way, and compared to their equivalents, recognized in other phytogeographical areas. These results are applied to the protective gestion of secondary communities of great floristical and phytogeographical interest, specially heaths, lawns, initial stages and some peat bog communities. In conclusion, the original phytogeographical position of this area, forming an enclave with boreo-continental affinities in the subatlantic belt, is stated
Higgins, Kellina Leslie. "Effet de la végétation sur la variabilité de la profondeur de dégel à petite échelle dans un paysage de tourbières en forêt boréale dans les Territoires du Nord-Ouest". Thèse, 2015. http://hdl.handle.net/1866/12562.
In order to better understand the impacts of climate change on permafrost degradation, it is important to understand the influence of abiotic and biotic factors on permafrost dynamics. While studies allude to the effect of broad vegetation groups on permafrost dynamics at landscape-scale, the role vegetation plays in affecting the spatial variability of active-layer development on the scale of metres, as explored here, is largely unknown. The study was carried out in a boreal forest-peatland landscape in the discontinuous permafrost zone in the southern Northwest Territories (N61°18’, W121°18’). We examined the influence of the following vegetation characteristics on the spatial variability of thaw depth: tree density, shrub cover, leaf area index, and cryptogam presence (lichen and bryophyte). We found that greater tree density was associated with shallower thaw depths while shrub cover (<50cm height) had a negligible influence. Furthermore, thaw depth depended on the cryptogam species cover and microform. This research quantifies the impact of vegetation by strata on thaw depth and may ultimately serve to refine vegetation parameters in ecosystem models and land surface schemes as part of climate models.
Tremblay, Louis. "Reconstitution paléoécologique du développement des mares dans deux tourbières minérotrophes structurées du Québec subarctique". Mémoire, 2010. http://www.archipel.uqam.ca/4704/1/M11784.pdf.
Moisan, Chantale. "Facteurs associés à la présence d’une orchidée rare au Québec : Arethusa bulbosa L". Thèse, 2011. http://hdl.handle.net/1866/6035.
Arethusa bulbosa L. is a peatland orchid rare in Québec because of the small size of its populations and the pressures on its habitat. It is known to be intolerant to edaphic changes of its habitat, and particularly to drainage. To determine if A. bulbosa is a good indicator species of the ecological integrity of peatlands, this study compares plots where the species is present from plots where it is absent. During the summers of 2009 and 2010, 37 peatlands were surveyed in southern Québec. Discriminant analyses were performed to find which natural or anthropogenic factors best explain the difference between plots with or without the orchid. Also, indicator species of the presence of A. bulbosa were found using INDVAL analyses. Overall, the results suggest that A. bulbosa was mostly growing in peatlands characterized by minerotrophic conditions. Two evidences supported this point, the high pH values measured and the presence of indicator species of minerotrophy in plots with the orchid. It is likely that A. bulbosa is favored by a certain interception of light by scattered trees or species growing in lower strata. Finally, despite a high floristic quality assessment index (FQAI) in A. bulbosa plots, it is likely that the species takes advantage of small-scale disturbances in it habitat and is therefore not a good indicator species of peatlands ecological integrity.