98 research outputs found
Interactions entre composition fonctionnelle de communautés végétales et formation des sols sans des lits de ravines en cours de restauration écologique
L activitĂ© Ă©rosive des badlands marneux des Alpes du Sud prĂ©sente des consĂ©quences nĂ©gatives pour l homme qui a ainsi cherchĂ© Ă restaurer ces terrains dĂšs le XIXĂšme siĂšcle. Depuis une dizaine d annĂ©es, une stratĂ©gie d ingĂ©nierie Ă©cologique y est dĂ©veloppĂ©e et se concentre sur les lits de ravines, pierres angulaires de leur restauration. La question appliquĂ©e Ă la base de ce travail de thĂšse est d identifier comment l implantation d ouvrages de gĂ©nie Ă©cologique dans lelit de ravines marneuses Ă©rodĂ©es favorise leur restauration Ă©cologique sur le long terme.L objectif de recherche associĂ© Ă cette question est de mieux comprendre comment des communautĂ©s vĂ©gĂ©tales interagissent avec la restauration des sols de lits de ravines Ă©rodĂ©es sur le long terme. Nous avons fait l hypothĂšse que les traits vĂ©gĂ©taux des plantes Ă l Ă©chelle de communautĂ©s constituent un point d entrĂ©e pertinent pour Ă©tudier ces interactions. Dans la premiĂšre partie, nous avons utilisĂ© les traits comme un outil de comprĂ©hension de l effet mĂ©canique des plantes sur les dynamiques gĂ©omorphologiques des lits de ravines en cours de restauration. Nous avons notamment montrĂ© que les traits permettent d expliquer la capacitĂ© de communautĂ©s vĂ©gĂ©tales implantĂ©es Ă favoriser la formation d amas sĂ©dimentaires dans le lit des ravines durant la premiĂšre dĂ©cennie post-travaux. Dans la deuxiĂšme partie, nous nous sommes intĂ©ressĂ©s Ă l Ă©volution potentielle sur le long terme (centaine d annĂ©es) des propriĂ©tĂ©s de ces amas, constituant des sols en devenir. Nous avons montrĂ© que la diversitĂ© ainsi que les valeurs dominantes des traits vĂ©gĂ©taux influencent les propriĂ©tĂ©s de ces sols, notamment la stabilitĂ© des agrĂ©gats et la fertilitĂ© des sols. En plus d ĂȘtre un outil de comprĂ©hension, nous montrons que cette utilisation des traits constitue un outil pour guider les actions de restauration de badlands via l implantation d ouvrages de gĂ©nie Ă©cologique, en apportant des Ă©lĂ©ments sur le devenir gĂ©omorphologique et Ă©cologique post-travaux des systĂšmes sol-plante de lits de ravines.In the French Southern Alps, severe erosion in marly badlands shows negative consequencesfor human populations, who worked to restore these terrains since the XIXth century. For adecade, an ecological engineering strategy is developed and focuses on gully beds, cornerstonesof their restoration. The operational question at the root of this PhD project is to identify towhat extent ecological engineering structures implanted in marly gully beds can foster theirlong-term ecological restoration. The scientific objective related to this question is to betterunderstand how plant communities interact in the long-term with the restoration of soils ingully beds. We hypothesized that plant traits at the community scale is a relevant entry point tostudy these interactions. In the first part, we used traits as a tool to study the mechanical effectof plants on geomorphological dynamics in gully beds under restoration. In particular, weshowed that traits enable us to explain the capacity of plant communities to favor theaccumulation of sediment mounds in gully beds during the first decade after ecologicalengineering works. In the second part, we concentrated on the potential long-term (century)evolution of the properties of these sediment mounds, in the process of becoming real soils. Weshowed that both trait diversity and dominant values of traits interacted with the properties ofthese soils, such as soil aggregate stability and soil fertility. With a strong multidisciplinaryapproach, this work provides results and insights on the interactions between plant traits andecosystem functioning in the specific case of highly eroded semi-natural ecosystems. It alsocontribute to set tools to restore badlands via ecological engineering works, by providinginformation about the long-term geomorphological and ecological evolution of soil-plantsystems in restored gully beds.SAVOIE-SCD - Bib.Ă©lectronique (730659901) / SudocGRENOBLE1/INP-Bib.Ă©lectronique (384210012) / SudocGRENOBLE2/3-Bib.Ă©lectronique (384219901) / SudocSudocFranceF
Modification des traits racinaires le long dâune succession secondaire sur des talus routiers: implications dans la dynamique des communautĂ©s et la protection des sols contre lâĂ©rosion
Les traits fonctionnels des plantes varient au cours des successions secondaires vĂ©gĂ©tales. Alors que certains traits ont Ă©tĂ© largement Ă©tudiĂ©s, les variations des traits racinaires au cours des successions restent relativement peu documentĂ©es. Lâobjectif de cette Ă©tude vise Ă mieux comprendre en quoi des variations de traits racinaires le long dâune succession secondaire contribuent Ă la dynamique de communautĂ©s vĂ©gĂ©tales mĂ©diterranĂ©ennes. Pour cela, quinze communautĂ©s vĂ©gĂ©tales, ĂągĂ©es de 0 Ă 69 ans, ont Ă©tĂ© repĂ©rĂ©es sur des talus en bordures de routes, dans le nord MontpelliĂ©rain. Sur cette chronosĂ©quence, nous nous intĂ©ressons Ă des traits racinaires morphologiques et architecturaux des espĂšces dominantes, reprĂ©sentant 70% de lâabondance vĂ©gĂ©tale. Nous faisons lâhypothĂšse que des traits morphologiques des racines fines (< 2 mm) permettent de mieux comprendre les modifications des stratĂ©gies dâacquisition et de conservation des ressources en nutriments et en eau. Des traits architecturaux, tels que la prĂ©sence dâun pivot, de racines traçantes et/ou adventives, permettent dâĂ©tudier le rĂŽle des racines dans lâancrage et la capacitĂ© des espĂšces Ă coloniser le milieu en rĂ©ponse aux contraintes topographiques liĂ©es Ă la pente des talus. Dans cette communication, nous prĂ©sentons (i) la mĂ©thode retenue pour lâĂ©tude des traits racinaires morphologiques et architecturaux sur des espĂšces de formes de croissance diverses (herbacĂ©es, buissons, arbres) et (ii) discutons des limites et atouts de ces mĂ©thodes. Enfin, nous discutons de lâimplication de ces traits racinaires dans la capacitĂ© des communautĂ©s Ă limiter lâĂ©rosion superficielle des talu
Soil and water bioengineering: practice and research needs for reconciling natural hazard control and ecological restoration
Soil and water bioengineering is a technology that encourages scientists and practitioners to combine their knowledge and skills in the management of ecosystems with a common goal to maximize benefits to both man and the natural environment. It involves techniques that use plants as living building materials, for: (i) natural hazard control (e.g., soil erosion, torrential floods and landslides) and (ii) ecological restoration or nature-based re-introduction of species on degraded lands, river embankments, and disturbed environments. For a bioengineering project to be successful, engineers are required to highlight all the potential benefits and ecosystem services by documenting the technical, ecological, economic and social values. The novel approaches used by bioengineers raise questions for researchers and necessitate innovation from practitioners to design bioengineering concepts and techniques. Our objective in this paper, therefore, is to highlight the practice and research needs in soil and water bioengineering for reconciling natural hazard control and ecological restoration. Firstly, we review the definition and development of bioengineering technology, while stressing issues concerning the design, implementation, and monitoring of bioengineering actions. Secondly, we highlight the need to reconcile natural hazard control and ecological restoration by posing novel practice and research questions
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Ectomycorrhizal fungal communities and their functional traits mediate plantâsoil interactions in trace element contaminated soils
There is an increasing consensus that microbial communities have an important role in mediating ecosystem processes. Trait-based ecology predicts that the impact of the microbial communities on ecosystem functions will be mediated by the expression of their traits at community level. The link between the response of microbial community traits to environmental conditions and its effect on plant functioning is a gap in most current microbial ecology studies. In this study, we analyzed functional traits of ectomycorrhizal fungal species in order to understand the importance of their community assembly for the soilâplant relationships in holm oak trees (Quercus ilex subsp. ballota) growing in a gradient of exposure to anthropogenic trace element (TE) contamination after a metalliferous tailings spill. Particularly, we addressed how the ectomycorrhizal composition and morphological traits at community level mediate plant response to TE contamination and its capacity for phytoremediation. Ectomycorrhizal fungal taxonomy and functional diversity explained a high proportion of variance of tree functional traits, both in roots and leaves. Trees where ectomycorrhizal fungal communities were dominated by the abundant taxa Hebeloma cavipes and Thelephora terrestris showed a conservative root economics spectrum, while trees colonized by rare taxa presented a resource acquisition strategy. Conservative roots presented ectomycorrhizal functional traits characterized by high rhizomorphs formation and low melanization which may be driven by resource limitation. Soil-to-root transfer of TEs was explained substantially by the ectomycorrhizal fungal species composition, with the highest transfer found in trees whose roots were colonized by Hebeloma cavipes. Leaf phosphorus was related to ectomycorrhizal species composition, specifically higher leaf phosphorus was related to the root colonization by Thelephora terrestris. These findings support that ectomycorrhizal fungal community composition and their functional traits mediate plant performance in metal-contaminated soils, and have a high influence on plant capacity for phytoremediation of contaminants. The study also corroborates the overall effects of ectomycorrhizal fungi on ecosystem functioning through their mediation over the plant economics spectrum
Belowground Biodiversity Relates Positively to Ecosystem Services of European Forests
Environmental Biolog
Soil multifunctionality and drought resistance are determined by plant structural traits in restoring grassland
It is increasingly recognized that belowground responses to vegetation change are closely linked to plant functional traits. However, our understanding is limited concerning the relative importance of different plant traits for soil functions and of the mechanisms by which traits influence soil properties in the real world. Here we test the hypothesis that taller species, or those with complex rooting structures, are associated with high rates of nutrient and carbon (C) cycling in grassland. We further hypothesized that communities dominated by species with deeper roots may be more resilient to drought. These hypotheses were tested in a 3âyr grassland restoration experiment on degraded exâarable land in southern England. We sowed three traitâbased plant functional groups, assembled using database derived values of plant traits, and their combinations into bare soil. This formed a range of plant trait syndromes onto which we superimposed a simulated drought 2 yr after initial establishment. We found strong evidence that community weighted mean (CWM) of plant height is negatively associated with soil nitrogen cycling and availability and soil multifunctionality. We propose that this was due to an exploitative resource capture strategy that was inappropriate in shallow chalk soils. Further, complexity of root architecture was positively related to soil multifunctionality throughout the season, with fine fibrous roots being associated with greater rates of nutrient cycling. Drought resistance of soil functions including ecosystem respiration, mineralization, and nitrification were positively related to functional divergence of rooting depth, indicating that, in shallow chalk soils, a range of water capture strategies is necessary to maintain functions. Finally, after 3 yr of the experiment, we did not detect any links between the plant traits and microbial communities, supporting the finding that traits based on plant structure and resource foraging capacity are the main variables driving soil function in the early years of grassland conversion. We suggest that screening recently restored grassland communities for potential soil multifunctionality and drought resilience may be possible based on rooting architecture and plant height. These results indicate that informed assembly of plant communities based on plant traits could aid in the restoration of functioning in degraded soil
Interactions entre composition fonctionnelle de communautés végétales et formation des sols sans des lits de ravines en cours de restauration écologique
In the French Southern Alps, severe erosion in marly badlands shows negative consequencesfor human populations, who worked to restore these terrains since the XIXth century. For adecade, an ecological engineering strategy is developed and focuses on gully beds, cornerstonesof their restoration. The operational question at the root of this PhD project is to identify towhat extent ecological engineering structures implanted in marly gully beds can foster theirlong-term ecological restoration. The scientific objective related to this question is to betterunderstand how plant communities interact in the long-term with the restoration of soils ingully beds. We hypothesized that plant traits at the community scale is a relevant entry point tostudy these interactions. In the first part, we used traits as a tool to study the mechanical effectof plants on geomorphological dynamics in gully beds under restoration. In particular, weshowed that traits enable us to explain the capacity of plant communities to favor theaccumulation of sediment mounds in gully beds during the first decade after ecologicalengineering works. In the second part, we concentrated on the potential long-term (century)evolution of the properties of these sediment mounds, in the process of becoming real soils. Weshowed that both trait diversity and dominant values of traits interacted with the properties ofthese soils, such as soil aggregate stability and soil fertility. With a strong multidisciplinaryapproach, this work provides results and insights on the interactions between plant traits andecosystem functioning in the specific case of highly eroded semi-natural ecosystems. It alsocontribute to set tools to restore badlands via ecological engineering works, by providinginformation about the long-term geomorphological and ecological evolution of soil-plantsystems in restored gully beds.LâactivitĂ© Ă©rosive des badlands marneux des Alpes du Sud prĂ©sente des consĂ©quences nĂ©gatives pour lâhomme qui a ainsi cherchĂ© Ă restaurer ces terrains dĂšs le XIXĂšme siĂšcle. Depuis une dizaine dâannĂ©es, une stratĂ©gie dâingĂ©nierie Ă©cologique y est dĂ©veloppĂ©e et se concentre sur les lits de ravines, pierres angulaires de leur restauration. La question appliquĂ©e Ă la base de ce travail de thĂšse est dâidentifier comment lâimplantation dâouvrages de gĂ©nie Ă©cologique dans lelit de ravines marneuses Ă©rodĂ©es favorise leur restauration Ă©cologique sur le long terme.Lâobjectif de recherche associĂ© Ă cette question est de mieux comprendre comment des communautĂ©s vĂ©gĂ©tales interagissent avec la restauration des sols de lits de ravines Ă©rodĂ©es sur le long terme. Nous avons fait lâhypothĂšse que les traits vĂ©gĂ©taux des plantes Ă lâĂ©chelle de communautĂ©s constituent un point dâentrĂ©e pertinent pour Ă©tudier ces interactions. Dans la premiĂšre partie, nous avons utilisĂ© les traits comme un outil de comprĂ©hension de lâeffet mĂ©canique des plantes sur les dynamiques gĂ©omorphologiques des lits de ravines en cours de restauration. Nous avons notamment montrĂ© que les traits permettent dâexpliquer la capacitĂ© de communautĂ©s vĂ©gĂ©tales implantĂ©es Ă favoriser la formation dâamas sĂ©dimentaires dans le lit des ravines durant la premiĂšre dĂ©cennie post-travaux. Dans la deuxiĂšme partie, nous nous sommes intĂ©ressĂ©s Ă lâĂ©volution potentielle sur le long terme (centaine dâannĂ©es) des propriĂ©tĂ©s de ces amas, constituant des sols en devenir. Nous avons montrĂ© que la diversitĂ© ainsi que les valeurs dominantes des traits vĂ©gĂ©taux influencent les propriĂ©tĂ©s de ces sols, notamment la stabilitĂ© des agrĂ©gats et la fertilitĂ© des sols. En plus dâĂȘtre un outil de comprĂ©hension, nous montrons que cette utilisation des traits constitue un outil pour guider les actions de restauration de badlands via lâimplantation dâouvrages de gĂ©nie Ă©cologique, en apportant des Ă©lĂ©ments sur le devenir gĂ©omorphologique et Ă©cologique post-travaux des systĂšmes sol-plante de lits de ravines
Interactions entre composition fonctionelle de communautés végétales et formation des sols dans les lits de ravines en cours de restauration écologique
(trad auto)The erosive activity of the marl badlands of the Southern Alps has negative consequences for mankind, who has sought to restore these lands since the 19th century. Over the past ten years, an ecological engineering strategy has been developed there and focuses on gully beds, the cornerstones of their restoration. The question applied to the basis of this thesis work is to identify how the establishment of ecological engineering structures in the bed of eroded marl gullies promotes their ecological restoration in the long term. The research objective associated with this question is to better understand how plant communities interact with the restoration of eroded gully bed soils over the long term. We hypothesized that plant traits of plants at the community level are a relevant entry point for studying these interactions. In the first part, we used the features as a tool to understand the mechanical effect of plants on the geomorphological dynamics of gully beds undergoing restoration. In particular, we have shown that the features explain the ability of established plant communities to promote the formation of sedimentary clusters in the gully bed during the first decade after work. In the second part, we looked at the potential long-term evolution (100 years) of the properties of these clusters, which constitute soil in the making. We have shown that the diversity and dominant values of plant traits influence the properties of these soils, including aggregate stability and soil fertility. In addition to being a tool for understanding, we show that this use of features constitutes a tool to guide badlands restoration actions through the implementation of ecological engineering works, by providing elements on the post-work geomorphological and ecological future of soil-plant systems of gully beds.LâactivitĂ© Ă©rosive des badlands marneux des Alpes du Sud prĂ©sente des consĂ©quences nĂ©gatives pour lâhomme qui a ainsi cherchĂ© Ă restaurer ces terrains dĂšs le XIXĂšme siĂšcle. Depuis une dizaine dâannĂ©es, une stratĂ©gie dâingĂ©nierie Ă©cologique y est dĂ©veloppĂ©e et se concentre sur les lits de ravines, pierres angulaires de leur restauration. La question appliquĂ©e Ă la base de ce travail de thĂšse est dâidentifier comment lâimplantation dâouvrages de gĂ©nie Ă©cologique dans le lit de ravines marneuses Ă©rodĂ©es favorise leur restauration Ă©cologique sur le long terme. Lâobjectif de recherche associĂ© Ă cette question est de mieux comprendre comment des communautĂ©s vĂ©gĂ©tales interagissent avec la restauration des sols de lits de ravines Ă©rodĂ©es sur le long terme. Nous avons fait lâhypothĂšse que les traits vĂ©gĂ©taux des plantes Ă lâĂ©chelle de communautĂ©s constituent un point dâentrĂ©e pertinent pour Ă©tudier ces interactions. Dans la premiĂšre partie, nous avons utilisĂ© les traits comme un outil de comprĂ©hension de lâeffet mĂ©canique des plantes sur les dynamiques gĂ©omorphologiques des lits de ravines en cours de restauration. Nous avons notamment montrĂ© que les traits permettent dâexpliquer la capacitĂ© de communautĂ©s vĂ©gĂ©tales implantĂ©es Ă favoriser la formation dâamas sĂ©dimentaires dans le lit des ravines durant la premiĂšre dĂ©cennie post-travaux. Dans la deuxiĂšme partie, nous nous sommes intĂ©ressĂ©s Ă lâĂ©volution potentielle sur le long terme (centaine dâannĂ©es) des propriĂ©tĂ©s de ces amas, constituant des sols en devenir. Nous avons montrĂ© que la diversitĂ© ainsi que les valeurs dominantes des traits vĂ©gĂ©taux influencent les propriĂ©tĂ©s de ces sols, notamment la stabilitĂ© des agrĂ©gats et la fertilitĂ© des sols. En plus dâĂȘtre un outil de comprĂ©hension, nous montrons que cette utilisation des traits constitue un outil pour guider les actions de restauration de badlands via lâimplantation dâouvrages de gĂ©nie Ă©cologique, en apportant des Ă©lĂ©ments sur le devenir gĂ©omorphologique et Ă©cologique post-travaux des systĂšmes sol-plante de lits de ravines
CMS (compact muon solenoid) deneyinde aÄır fiziÄi araĆtırmaları
TEZ6695Tez (YĂŒksek Lisans) -- Ăukurova Ăniversitesi, Adana, 2008.Kaynakça (s.82-84) var.ix, 85 s. : rnk.res. ; 29 cm.A new state of matter called ""quark-gluon plasma"" where quarks and gluons are deconfinement is formed, at the collision of heavy ions with high energy. Physicsts believe that it is possible to understand strong interactions at the fundamental level by searching quark-gluon plasma (QGP) The Large Hadron Collider (LHC) will also collide heavy ions at the nucleon-nucleon center of mass energy of 5.5 TeV in addition to the proton-proton collisions to find stronger evidence for QGP. In this thesis, an overview of heavy ion physics issues that are planned to study in CMS experiment are given.AÄır iyonlar çok yĂŒksek enerjilerde çarpıĆtırıldıklarında kuark ve gluonlar hadronlar içindeki hapislik durumundan kurtularak kuark-gluon plazması (KGP) adı verilen yeni bir madde formu oluĆmaktadır. Fizikçiler kuark-gluon plazmasını inceleyerek kuvvetli etkileĆmeyi temel seviyede anlamayı ĂŒmit etmektedirler. KGP'nın varlıÄına dair daha belirgin kanıtlar elde etmek amacıyla CERN'de bulunan BĂŒyĂŒk Hadron ĂarpıĆtırıcısı (BHĂ), 14 TeV'lik protonları çarpıĆtırmanın yanı sıra 5.5 TeV/nĂŒkleon aÄır iyonları da çarpıĆtıracaktır. Bu çalıĆmada, CMS deneyindeki aÄır iyon çarpıĆmasında gözlenmesi planlanan fizik konuları derlenmiĆtir.Bu çalıĆma Ă.Ă. Bilimsel AraĆtırma Projeleri Birimi Tarafından DesteklenmiĆtir. Proje No:FEF.2006.YL.5
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