Dissertations / Theses on the topic 'Biologie des invasions'
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Bertelsmeier, Cleo. "Biologie des invasions de fourmis dans un contexte de changement climatique." Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112358/document.
Climate change and biological invasions are both among the greatest threats to biodiversity and their impacts might increase by the end of the century. Among invasive species, ants are a prominent group due to their negative impacts on native species, ecosystem processes, human and animal health, agro-ecosystems and the economy. The objective of this thesis was to forecast future ant invasions – especially in the light of on-going climate change, which is generally thought to favour invasive species by removing thermal barriers. I used three complementary approaches to study the potential of different ant species to invade in the future: species distribution modelling, behavioural experiments and the analysis of a database of ecological traits. I modelled suitable area for 15 of the worst invasive ant species, both currently and with predicted climate change, globally, regionally and within the world’s 34 biodiversity hotspots. Surprisingly, the potential distribution of only five species was predicted to increase (up to 35.8%) with climate change, with most declining by up to 63.3%. The ant invasion hotspots are predominantly in tropical and subtropical regions of South America, Africa, Asia and Oceanic islands, and particularly correspond with biodiversity hotspots. Contrary to general expectations, climate change and biological invasions will not systematically act synergistically for ants. In addition, I found that the impacts of climate change can change over time and even reverse the trend of the impact (i.e., an increase instead of a decrease or vice versa). However, ant invasions will likely remain as a major global problem, especially where invasion hotspots coincide with biodiversity hotspots. The species distribution models have identified large potentially overlapping distributions of several invasive ants. In the future, these species may arrive simultaneously in the same regions and compete with each other. In a series of experiments, I tested behavioural differences among 7 highly invasive ant species (Anoplolepis gracilipes, Paratrechina longicornis, Myrmica rubra, Linepithema humile, Lasius neglectus, Wasmannia auropunctata and Pheidole megacephala). I discovered two different behavioural strategies among invasive ants. Interactions at the colony level, exhibited more complex demographic processes and more variability. Further, I investigated resource competition and differences in resource exploitation. I found significant differences among species, with competitive abilities that were negatively correlated with behavioural dominance. This series of experiments suggests that the ‘mechanisms’ of invasiveness are more complex than previously thought and that different invasive ant species may use different behavioural strategies. Since there are more than 250 exotic species of ants, it would be interesting to identify potential future invaders. In order to identify traits associated with invasiveness in ants, I set up a database with 2193 ant species and 24 ecological characteristics. I performed a preliminary analysis of trait differences between native and invasive ants that shows clearly different clusters of invasive and native species, with exotic species in between. These results could be used as a basis to construct a predictive model of future ant invasions. The different methods used (models, experiments, database) are complementary in that they explore different aspects of the future ant invasions which are likely to be influenced by on-going climate change. The worst invaders of tomorrow may not be the same as today and similarly, areas most at risk are likely to change
Tayeh, Ashraf. "De la lutte biologique à l’invasion : la coccinelle Harmonia axyridis comme espèce modèle." Electronic Thesis or Diss., Montpellier, SupAgro, 2013. http://www.theses.fr/2013NSAM0038.
Biological control is generally considered as an environmentally low-impact solution for pest control. However, the use of foreign control agents may ultimately lead to undesired biological invasions. The Asian harlequin ladybird Harmonia axyridis Pallas (Coleoptera: Coccinellidae) was originally used as a biological control agent of aphids in North America and Europe. This species is now considered as invasive, and can have harmful effects on the environment. The main objective of this thesis is to better understand the impact of mass rearing on life-history traits, with a focus on traits that may be associated with invasion success. To do so, experimental approaches were carried out to monitor changes in life-history traits for three types of populations (biocontrol, native or invasive). The corresponding results indicate that the most important evolutionary changes occur in the biocontrol populations (by contrast with the invasive and native populations). Mass rearing appears to induce significant phenotypic changes in the biocontrol populations, with the most spectacular changes being related to reproductive life-history traits. For instance, biocontrol females reproduce significantly earlier, have a higher daily fecundity, but also exhibit lower life expectancy and lower reproductive lifespan. We also evidence other differences between the native and invasive populations. Cold tolerance and pathogen resistance are also lower in biocontrol populations than in wild populations. Altogether, our findings indicate that adaptations to mass rearing conditions may affect the fitness of H. axyridis populations in natural environments. This suggests that, even if the European biocontrol strain is unable to successfully colonize a natural environment, it may nonetheless impact the invasion dynamics of the species in Europe thanks to the admixture with the invasive American population
Ruland, Florian [Verfasser]. "The Role of Behavioural Changes in Biological Invasions / Florian Ruland." Berlin : Freie Universität Berlin, 2020. http://d-nb.info/1212031970/34.
Tayeh, Ashraf. "De la lutte biologique à l’invasion : la coccinelle Harmonia axyridis comme espèce modèle." Thesis, Montpellier, SupAgro, 2013. http://www.theses.fr/2013NSAM0038/document.
Biological control is generally considered as an environmentally low-impact solution for pest control. However, the use of foreign control agents may ultimately lead to undesired biological invasions. The Asian harlequin ladybird Harmonia axyridis Pallas (Coleoptera: Coccinellidae) was originally used as a biological control agent of aphids in North America and Europe. This species is now considered as invasive, and can have harmful effects on the environment. The main objective of this thesis is to better understand the impact of mass rearing on life-history traits, with a focus on traits that may be associated with invasion success. To do so, experimental approaches were carried out to monitor changes in life-history traits for three types of populations (biocontrol, native or invasive). The corresponding results indicate that the most important evolutionary changes occur in the biocontrol populations (by contrast with the invasive and native populations). Mass rearing appears to induce significant phenotypic changes in the biocontrol populations, with the most spectacular changes being related to reproductive life-history traits. For instance, biocontrol females reproduce significantly earlier, have a higher daily fecundity, but also exhibit lower life expectancy and lower reproductive lifespan. We also evidence other differences between the native and invasive populations. Cold tolerance and pathogen resistance are also lower in biocontrol populations than in wild populations. Altogether, our findings indicate that adaptations to mass rearing conditions may affect the fitness of H. axyridis populations in natural environments. This suggests that, even if the European biocontrol strain is unable to successfully colonize a natural environment, it may nonetheless impact the invasion dynamics of the species in Europe thanks to the admixture with the invasive American population
Datta, Arunava [Verfasser]. "Analysing plant invasions across multiple scales using Ageratina adenophora as a case study / Arunava Datta." Halle, 2018. http://d-nb.info/116213433X/34.
Schittko, Conrad [Verfasser]. "On species invasions in urban grasslands : Interactions with soil biota, functional diversity, and global change / Conrad Schittko." Berlin : Freie Universität Berlin, 2015. http://d-nb.info/1065670230/34.
Thioulouse, Jean. "Structures spatio-temporelles en biologie des populations d'insectes : application à l'étude de l'altise du colza (Psylliodes chrysocephala L.), résultats méthodologiques et biologiques." Lyon 1, 1985. http://www.theses.fr/1985LYO11653.
Lombaert, Eric. "Biologie évolutive d'une espèce envahissante, la coccinelle asiatique Harmonia axyridis." Electronic Thesis or Diss., Montpellier 2, 2011. http://www.theses.fr/2011MON20248.
Biological invasions are a concern because of their increase and their environmental, economic and human health consequences. To become invasive, a population must (i) be introduced, (ii) established itself and (iii) proliferates. Each of these three steps constitutes a challenge, and the processes involved are still poorly understood. This thesis describes a set of research actions which aims at understanding the worldwide successful invasion of the Asian ladybird Harmonia axyridis.We first investigated the introduction step by retracing invasion routes of H. axyridis using microsatellite markers and the ABC (Approximate Bayesian Computation) method. We have shown that the oldest invasive population in the eastern North America acted as a bridgehead of the worldwide invasion by becoming the source of the European, the South American and the African outbreaks. We also found evidence for a genetic admixture event in Europe with a biological control strain.Second, we explored the establishment step. We have shown that invasive populations of H. axyridis endured a genetic purge which significantly reduced adverse effects associated with inbreeding depression. In addition, the admixture event in Europe likely brought phenotypic benefits to this invasive population.We then studied several aspects of the proliferation step. We found that European populations had evolved towards higher dispersal abilities on the invasion front. Moreover, our results show that the use of a flightless biocontrol strain which is still sold in France may have a positive impact on the expansion of the invasive population through heterosis or increased of genetic variance.Finally, we discuss the importance of studying in detail a model species such as H. axyridis to improve our general understanding of the eco-evolutionary mechanisms involved in biological invasions
Wauters, Nina. "Genetical and ecological aspects of the invasion of the tropical fire ant Solenopsis geminata in the Galapagos Islands." Doctoral thesis, Universite Libre de Bruxelles, 2015. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209088.
biodiversity, human health and economy. Their effects are especially important on fragile and
unique insular biotas such as the Galápagos Islands. Ants in particular are keystone species
implicated in ecosystem functioning and biodiversity and they can be dramatic invaders. In
the Galápagos Islands, the tropical fire ant Solenopsis geminata is considered a high-impact
invasive species, though it remains surprisingly poorly studied. The objectives of this work
are to document the invasion of S. geminata in the Galápagos Islands by 1) updating its
distribution; 2) determining its reproduction and dispersal strategies and reconstruct its
invasion history throughout the archipelago and 3) evaluating its impact on the native fauna
(focusing on ants and arthropods communities and endemic land tortoises).
First, we added 66 new records of S. geminata in the Galápagos since 2008. It has
now been recorded on seven islands and 11 islets in a wide range of habitats, including
nesting sites of 24 endemic and/or endangered vertebrate species, for which it constitutes a
potential threat.
Secondly, by combining Bayesian clustering methods, coalescent-based scenario
testing using microsatellite data and historical records, we determined that genetic diversity
of populations of S. geminata collected in Galápagos Islands is significantly lower than the
genetic diversity of populations from native areas (Costa Rica). The Galápagos populations
form three clusters corresponding to an island or groups of islands. They appear to be the
result of a single introduction in the first half of the 19th century, probably from mainland
Ecuador, which acted as a bridgehead population to two subsequent introductions within the
archipelago, corresponding human colonization fluxes in the archipelago.
We sampled ants in all main habitats of Santa Cruz Island. Introduced ant species
were largely prevalent, and S. geminata was the dominant species and was associated with
low evenness of ant communties and lower abundance of native ants. We found that
Galápagos’ ant communities are determined by the vegetation type and altitude, but found
only little evidence for competitively structured assemblages, except in disturbed areas.
The arthropod diversity was investigated in two agricultural sites of Santa Cruz Island
by combining three complementary sampling techniques. More than half of the species were
either endemic or native, but introduced species constituted the majority of the catches.
Solenopsis geminata was by far the most abundant and common species.
Finally, we investigated the mortality of Cheloidis land tortoise’s eggs and hatchlings
in an area infested by S. geminata on Santa Cruz Island with regard to the abundance of fire
ants and the duration of incubation. Egg survival was negatively associated with longer incubation times but we found no direct relation between ant density and tortoise mortality
despite a high abundances of fire ants in the vicinity of the majority of the tortoise burrows.
Our work allows addressing ecological and genetical aspects of the invasion of S.
geminata in the Galápagos Islands. We analyzed our results in the light of an ecoevolutionary
framework presenting different invasion scenarios and discussed S. geminata
as an invasive ant. This provided us with information useful for the study and management of
this invasive species in the Galápagos Islands.
/
Les espèces invasives constituent un défi majeur à cause de leur impact sur la
biodiversité, la santé humaine et l’économie. Leurs effets sont particulièrement importants
sur les environnements insulaires fragiles et uniques comme les île Galápagos. Les fourmis
en particulièr sont des espèces clé de voûte du fonctionnement des écosystèmes et de la
biodiversité. Elles peuvent de ce fait devenir des envahisseurs spectaculaires. Dans les îles
Galápagos, la fourmi de feu tropicale Solenopsis geminata fait partie des espèces invasives
à haut impact et cependant elle a été étonnamment peu étudiée. Les objectifs de ce travail
consistent à documenter l’invasion de S. geminata dans l’archipel des Galápagos: 1) en
mettant à jour sa distribution; 2) en déterminant ses stratégies de reproduction et de
dispersion et en reconstruisant l’histoire de son invasion dans l’archipel et 3) en évaluant son
impact sur la faune native (particulièrement sur les communautés de fourmis et
d’arthropodes et sur les tortues terrestres endémiques).
Tout d’abord, nous avons ajouté 66 nouveaux relevés de S.geminata aux Galápagos
depuis 2008. À ce jour, la fourmi a été observée sur 7 îles et 11 îlots, et ce dans une grande
variété d’habitats. On la trouve également sur les sites de ponte de 24 espèces de vertébrés
endémiques ou en voie de disparition, qu’elle menace ainsi potentiellement.
Ensuite, en combinant des méthodes bayésiennes de regroupement et des
comparaisons de scénarios en se basant sur des séquences microsatellites et des données
historiques, nous avons montré que la diversité génétique des populations de S. geminata
des Galápagos est significativement inférieure à celle des populations des zones d’indigénat
(Costa Rica). Les populations des Galápagos - réparties en 3 groupes correspondant à une
île ou un groupe d’îles – sont le résultat d’une introduction unique ayant eu lieu dans la
première moitié du 19ème siècle. Elles proviennent vraisemblablement de l’Equateur
continental et constituent une population “tête de pont” pour deux introductions ultérieures au
sein de l’archipel. Ces mouvements correspondent aux flux de populations humaines.
Nous avons échantillonné les fourmis dans tous les principaux habitats de l’île de
Santa Cruz. Les fourmis introduites sont largement prévalentes. Solenopsis geminata
constitue l’espèce dominante et se trouve associée avec une faible équitabilité des
communautés de fourmis ainsi qu’avec une diminution de l’abondance des fourmis natives.
Nos résultats indiquent que les communautés de fourmis des Galápagos sont structurées
par le type de végétation et l’altitude, alors que les assemblages de fourmis ne sont pas
structurés compétitivement, à l’exception des zones perturbées.
Nous avons investigué la diversité arthropodienne de deux sites agricoles de l’île de
Santa Cruz en combinant trois méthodes d’échantillonnage complémentaires. Plus de la moitié des espèces collectées étaient soit endémiques, soit natives. Les espèces introduites
ont toutefois constitué la majorité des individus collectés. Solenopsis geminata était de loin la
plus abondante et la plus commune des espèces récoltées.
Enfin, dans une zones infestées par S. geminata sur l’île de Santa Cruz, nous avons
mis en relation la mortalité des oeufs et juvéniles de tortues terrestres Chelonoidis avec
l’abondance des fourmis de feu et la durée d’incubation des oeufs. Le taux de survie des
oeufs est négativement corrélé à leur durée d’incubation. Cependant, malgré de très hautes
abondances de fourmis de feu à proximité des nids de tortues, nous n’avons pas trouvé de
relation directe avec leur mortalité.
Pour conclure, ce travail aborde les aspects génétiques et écologiques de l’invasion
de la fourmi de feu tropicale dans les îles Galápagos. Nos résultats sont analysés au sein
d’un cadre éco-évolutif présentant différents scénarios d’invasion. Nous discutons également
de S. geminata en tant qu’espèce invasive. Nous espérons apporter des informations utiles
dans le cadre de l’étude et du contrôle de cette espèce invasive aux Galápagos.
Doctorat en Sciences
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Foucaud, Julien. "Biologie évolutive d'une fourmi envahissante à la sexualité insolite, Wasmannia auropunctata." École nationale supérieure agronomique (Montpellier), 2007. http://www.theses.fr/2007ENSA0032.
Mandon-Dalger, Isabelle. "Sélection de l'habitat et dynamique d'invasion d'un oiseau introduit, le cas du bulbul orphée à la Réunion." Rennes 1, 2002. http://www.theses.fr/2002REN10043.
Graß, Ingo [Verfasser], and Nina [Akademischer Betreuer] Farwig. "Habitat loss and exotic plant invasions disrupt plant-animal mutualisms in a heterogeneous South African landscape / Ingo Graß. Betreuer: Nina Farwig." Marburg : Philipps-Universität Marburg, 2014. http://d-nb.info/105193494X/34.
Lesieur, Vincent. "Invasion de la punaise américaine Leptoglossus occidentalis en Europe : une contribution à la compréhension des invasions fulgurantes." Thesis, Orléans, 2014. http://www.theses.fr/2014ORLE2045/document.
During the last decades, biological invasions were observed to increase exponentially, at an unprecedented rate and magnitude, in direct relation with the human activities, especially globalization. In this context, some invasive species spread very quickly in the area of introduction. The European invasion of Leptoglossus occidentalis is a good example of this phenomenon. This study aimed at testing some hypotheses to explain the rapidity of this invasion. To reach this goal, we used a multidisciplinary approach combining population genetics (analyzing samples from native and invaded areas) with a study of biological and ecological characteristics of the invasive populations. Through the use of molecular markers and Bayesian methods (ABC), we confirmed previous suspicions and demonstrated that the European invasion proceeded from multiple introductions in distant geographic areas. Our results also indicated that a primarily invaded area of Eastern North America acted as a bridgehead for the invasion in Europe. Moreover, population genetics, combined with an experimental measurement of the bug flight capabilities using flight mills, revealed that the intrinsic capacities of dispersion of this species are particularly high. The environmental conditions of the newly invaded areas in Europe did not constitute a barrier to the invasion of L. occidentalis. Its high degree of polyphagy was confirmed on European conifers, quite all species being susceptible to be exploited, thus favoring population establishment. . Furthermore, this study highlights the ecological threat represented by this insect which can affect the native flora in Europe. Actually, bug damage which can be important, seems to be additive to those of native insects exploiting cone and seed resources, thus decreasing the potential of natural regeneration. This work contributes to improve knowledge on biological invasions, especially to understand the reasons underlying the rapid spread observed in some invasive species, and highlights phenomenon underestimated until recently such as the Bridgehead scenario
Perdereau, Elfie. "Biologie de l'invasion d'un termite américain en France : évolution de l'organisation sociale et conséquences sur le succès invasif." Thesis, Tours, 2010. http://www.theses.fr/2010TOUR4024/document.
The increasing of ecological and economical problems linked to biological invasion phenomenon necessitate a better understanding of mechanisms allowing an invasive success. In social insects, studies are mainly focused on social Hymenoptera, and has demonstrated that social organization of introduced populations presented particular characters allowing their invasive success. The principal objective of my PhD is to characterize the social organization of the introduced populations in Isoptera through the study of the American termite Reticulitermes flavipes introduced in France. The overall of results reveals (i) strong variations of social organization between native and introduced populations presenting a extreme form of neoteny and a strong capacity to colonial fusion; (ii) these variations seem to have evolved after its introduction in France, and (iii) to allow the establishment and expansion of R. flavipes in France, similarly to unicoloniality and polygyny observed in the social invasive Hymenoptera. The possible evolutionary origins of the observed variations between native and introduced populations of R. flavipes are discussed
Urvois, Teddy. "Structure génétique et modélisation de la distribution des populations de deux espèces invasives de Xylosandrus (Scolytinae - Xyleborini) : deux espèces proches aux histoires d’invasion différentes." Electronic Thesis or Diss., Orléans, 2022. https://theses.univ-orleans.fr/prive/accesESR/2022ORLE1031_va.pdf.
Xylosandrus compactus and X. crassiusculus are two ambrosia beetles originating from Southeastern Asia and invasive on several continents, whose atypical biology and ecology favour invasion. During this thesis, a multidisciplinary approach was used to (i) identify the origin of invasive populations and their invasion routes and (ii) determine the areas in which they could spread and establish. Invasion routes were traced using a mitochondrial marker and genomic markers, and the suitable areas for each species were identified using species distribution models (SDM).Despite their ecological and phylogenetic proximity, the two species have different invasion histories. Two lineages were identified in X. compactus, one originating from India or Vietnam, who invaded Africa, and the other from the Shanghai area, who independently invaded the American-Pacific and Europe. X. crassiusculus comprises two very diverging clusters, mostly allopatric and with different ecological niches. Cluster 1 independently invaded Pacific islands and Africa. Cluster 2 is responsible for the invasion in the Americas, Europe, Africa and Oceania, with several independent introductions from multiple sources (including bridgehead, where an invasion occurs from an area already invaded) followed by intra-continental dispersion. For both species, SDM showed suitable areas where the pests are not present yet and which could be invaded. We expect an impact of climate change on their future potential distributions. Conversely, the recent evolution of climate is not responsible for their recent invasion in Europe, which has already been suitable for decades
Menzel, Andreas [Verfasser], Ingolf [Akademischer Betreuer] Kühn, Isabell [Akademischer Betreuer] Hensen, and Maarja [Akademischer Betreuer] Öpik. "Effects of the mycorrhizal symbiosis on plant distributions and alien plant invasions at a large spatial scale / Andreas Menzel ; Ingolf Kühn, Isabell Hensen, Maarja Öpik." Halle, 2016. http://d-nb.info/1116954842/34.
Ebeling, Susan K. [Verfasser], Isabell [Akademischer Betreuer] Hensen, Harald [Akademischer Betreuer] Auge, and Ingo [Akademischer Betreuer] Kowarik. "Does local adaptation facilitate the success of plant invasions? : a case study on Buddleja davidii / Susan K. Ebeling. Betreuer: Isabell Hensen ; Harald Auge ; Ingo Kowarik." Halle, Saale : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2008. http://d-nb.info/102493778X/34.
Grulois, Daphné. "Etude de la dispersion et du recrutement à différentes échelles spatiales chez Undaria pinnatifida, une macro-algue introduite le long des côtes bretonnes." Paris 6, 2010. http://hal.upmc.fr/tel-01111061.
Paul, Hannah-Vanessa Janine [Verfasser], Anna [Akademischer Betreuer] Starzinski-Powitz, and Ernst [Akademischer Betreuer] Stelzer. "Einfluss des Invasions-assoziierten Proteins Shrew-1 auf die E-Cadherin-Expression in epithelialen Endometriose-Zellen / Hannah-Vanessa Janine Paul. Gutachter: Anna Starzinski-Powitz ; Ernst Stelzer." Frankfurt am Main : Univ.-Bibliothek Frankfurt am Main, 2016. http://d-nb.info/1081212160/34.
Bonnaud, Elsa. "Ecologie trophique et impact d'un prédateur introduit (Felis silvestris catus) dans les écosystèmes insulaires." Aix-Marseille 3, 2008. http://www.theses.fr/2008AIX30080.
Biological invasions are the first threat for the island biodiversity. Cats predators introduced on islands, feed on a wide range species. Cats are assumed to have an impact on at least 167 vertebrates on 123 different islands and contributed to the extinction of at least 32 taxa. On Hyeres archipelago, the diet of this predatorwas mainly constituted by introduced mammals and birds. The ship rat, the rabbit and the Mediterranean endemic yelkouan shearwater, represented more than 90% of the biomass ingested by cats. The cat predation on the yelkouan shearwater was strong and recurrent. Cat impact was evaluated by using demographic matrix models. Under such cat predation pressure, the small shearwater population of Port-Cros needs to be sustained by immigrant birds Face to this strong threat of shearwater extirpation, cat eradication was conducted on Port-Cros Island leading to an increase of the shearwater population without any sign of mesopredator release
Herpigny, Basile. "Comparative approach of population biology and functional ecology of Fallopia japonica, F. sachalinensis and F. xbohemica in Belgium." Doctoral thesis, Universite Libre de Bruxelles, 2012. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209627.
susceptibles de sous-tendre des variations de capacité d'invasion, au sein du complexe de plantes envahissantes F. japonica, F. xbohemica et F. sachalinensis en Belgique. Ces trois taxons d'origine asiatique présentent un intérêt majeur en écologie des invasions car ils possèdent une aptitude à l'invasion contrastée bien qu'ils fassent partie du même complexe hybride, aient la même forme de vie, et la même distribution géographique.
En particulier, la thèse examine si Fallopia sachalinensis présente une combinaison particulière de traits fonctionnels liés à la capture et à l'utilisation des ressources susceptible d'expliquer sa capacité d'invasion plus faible. La thèse tâche également de déterminer si les hybrides sont intermédiaires entre les parents pour ces traits ou manifestent des propriétés originales susceptibles
d'entraîner un comportement plus invasif. Les traits fonctionnels pris en considération comprennent notamment l'architecture des parties aériennes, le SLA (surface foliaire spécifique), les teneurs foliaires en nutriments, la vitesse de décomposition des litières et la plasticité phénotypique de ces caractères. La stratégie scientifique repose sur trois approches complémentaires:
- des comparaisons in situ entre les taxons dans des sites ou ils coexistent;
- des cultures en conditions semi-contrôlées au jardin expérimental;
- une expérience de décomposition des litières.
Les résultats mettent en lumière la stratégie unique de capture et d'utilisation des ressources
de F. sachalinensis, ainsi que ses réponses plastiques moins adaptées (moins d'accroissement de la hauteur et de la surface foliaire totale en réponse a l'ombre, et de la biomasse et du nombre de tiges en réponse a une augmentation de la fertilité du sol). Cette stratégie contribue a sa capacité d'invasion plus faible en réduisant son efficacité d'utilisation et de capture de la lumière et des nutriments. D'autre part, l'hybride ne présente pas de valeurs transgressives pour les traits étudiés et est similaire à F. japonica en termes de traits et de plasticité. Toutefois, le nombre limité de
populations hybrides étudiées ne nous permet pas d'en conclure que l'hybride ne présente pas de
variation transgressive a l'échelle européenne. De plus, la variabilité génétique de l'hybride pourrait permettre une évolution future de sa capacité d'invasion, ce qui en fait une priorité pour la prévention et la gestion a l'échelle mondiale. / The objective of the thesis is to examine variation and evolution of functional traits that are susceptible to underlie variation of invasiveness in the invasive complex of Fallopia japonica, F. xbohemica and F. sachalinensis in Belgium. These three taxa originate from Asia and present a major interest in invasion ecology since they display contrasting invasiveness although they are part of the same hybrid complex, have the same life form and distribution area.
In particular, we ask if F. sachalinensis displays a specific combination of functional traits related to resource capture and use that is susceptible to explain its lower invasiveness. We also try to determine if the hybrids have intermediary trait values or if they show specific properties susceptible to increase their invasiveness. Functional traits measured include architecture, SLA (specific leaf area), nutrient foliar concentrations, litter decomposition rate and phenotypic plasticity of the same traits. Scientific strategy uses three different methods:
- in situ comparisons between the taxa in sites where they coexist;
- common gardens with semi controlled conditions;
- litter decomposition experiment.
Results show the unique strategy of F. sachalinensis concerning resource capture and use, as well as its less adaptive plastic responses (smaller increase of height and total leaf area in response to shade, and of biomass and shoot number in response to soil fertility). This strategy contributes to its lower invasiveness through a reduction in light and nutrient capture and use efficiency. The hybrid does not display transgressive variation for the studied traits and is similar to F. japonica concerning its traits and its plasticity. However, the limited number of hybrid accessions does not allow to conclude that the hybrid presents no transgressive variation throughout Europe. Moreover, genetic variability in the hybrid might allow future evolution of its invasiveness, making the hybrid a priority for prevention and management throughout the world.
Doctorat en Sciences
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Thibault, Isabel. "Invasion de la truite arc-en-ciel (Oncorhynchus mykiss) dans l'Est du Québec." Thesis, Université Laval, 2010. http://www.theses.ulaval.ca/2010/27510/27510.pdf.
Duyck, Pierre-François. "Compétition interspécifique et capacités invasives : le cas des Tephritidae de l'île de la Réunion." Phd thesis, Université de la Réunion, 2005. http://tel.archives-ouvertes.fr/tel-00470566.
Martel, Corine. "Invasions biologiques : source(s), profils d'expansion et impacts d'un gastéropode marin, Ocinebrellus inornatus, introduit accidentellement sur les côtes atlantiques françaises." La Rochelle, 2003. http://www.theses.fr/2003LAROS098.
Littoral ecosystems are particularly sensible to biological invasions because of human activities. However, the lack of knowledge on invasion processes fundamental mechanisms can explain the difficulty to determine common biological traits of invasive species and the lack of efficiency of prevention and control methods. We studied the invasion by an exotic marine gastropod, Ocinebrellus inornatus, which is susceptible to involve important economical impacts by feeding on oysters in parks of Marennes-Oléron bay, with the use of an ecological study based on population biology and genetics methods and concepts. At an intraspecific level, we tried to identify the introduction source, to analyse the colonization strategies and then at an interspecific level, to compare biological traits of introduced and resident species, and to evaluate hybridisation risks
Weil, Sarah Sophie. "Le rôle des traits des espèces dans la dispersion à différentes échelles - de la compréhension du passé profond aux processus actuels." Electronic Thesis or Diss., Université Grenoble Alpes, 2023. https://thares.univ-grenoble-alpes.fr/2023GRALV030.pdf.
A pressing challenge in ecology is to unravel the mechanisms that underlie the distribution of life at a global scale. Rare dispersal events across biogeographic barriers and establishment in new regions are central to this: these events determine the distribution of both the dispersing species and of species in the receiving community, and they can open opportunities for speciation. On smaller scales, dispersal is integral to species’ persistence, allowing them to respond to changes in their environment directly through movement or indirectly through adaptation. Not all species have the same ability to disperse and establish. Better understanding these differences has gained new urgency today if we are to accurately assess risks, challenges and conservation opportunities in the context of biological invasions, land-use and climate change. Species’ traits are thought to be an important factor in successful dispersal. For example, large species are often better dispersers than small species, and plants with seeds that can float are more likely to disperse over island archipelagos than those with seeds that sink. However, there have been few tests of theory on how species traits might support dispersal at large biogeographic scales. In this thesis, I combine biogeographic, macroecological and macroevolutionary approaches to identify the role of body size and life-history traits in dispersal, and to test the transferability of trait-dispersal relationships across scales. First, I quantify and compare the role of traits in biogeographic histories of 56 tetrapod clades. Second, I discuss in a conceptual synthesis if and how information from macroevolutionary and biogeographic studies can be used to better understand species present-day biological invasions, as well as present-day extinction risk due to changing environmental conditions. Third, I test conceptual considerations from this work on empirical data, linking the patterns observed in past biogeographic dispersal to present-day biological invasions and range shifts. Together these three strands highlight the importance of taxonomic, geographical and temporal contexts in the role of species traits in dispersal, which is an important step forward to better predictions of species’ abilities to respond to changing environmental conditions
Hess, Manon. "Restauration écologique des communautés végétales après éradication d'espèces invasives : Rôle de la dynamique de colonisation et des effets de priorité Using limiting similarity to enhance invasion resistance: theoretical and practical concerns Priority effects: Emerging principles for invasive plant species management Giving recipient communities a greater head start and including productive species boosts early resistance to invasion." Thesis, Avignon, 2020. http://www.theses.fr/2020AVIG0357.
Invasive plant species cause serious environmental and sanitary issues and their control is today a major challenge. Disturbances involving vegetation removal and an increase in resource availability offer particularly favorable conditions for invasive plant colonization. Establishing a plant cover rapidly sequestering resources could be a relevant strategy to limit invasion. However, little is known about the characteristics enabling newly established communities to exert strong invasion resistance, especially in the early growth stages.In this thesis, I focused on two potential determinants of invasion resistance of herbaceous plant communities in the early growth stages after a major disturbance, which are (1) the concept of limiting similarity, stating that the coexistence of species sharing the same ecological niche is limited by competitive exclusion, and (2) priority effects, which occur when the establishment of a species affects the performance or survival of later arriving species. The application of limiting similarity to control invasive plants appears complex, ineffective and unsuitable for the most common situations. In contrast, integrating priority effects into invasive plant management strategies seems more promising. One strategy consists in restoring a plant cover exerting strong negative priority effects, decreasing the success of subsequent invasive plant establishment. In two greenhouse experiments, I explored the role of priority effects in early invasion resistance. In a first experiment, I manipulated species composition, sowing density and the elapsed time between community sowing and invasion by Ambrosia artemisiifolia, Bothriochloa barbinodis and Cortaderia selloana. A higher invasion resistance was observed when communities produced a high aboveground biomass, which was associated with the presence of productive species. Delaying invasive species arrival also decreased invasion success, but only if it allowed a sufficient increase in biomass production. A second experiment investigated how the identity of the first native colonizer (one of two grasses: Dactylis glomerata and Lolium perenne, or one of two legumes: Onobrychis viciifolia and Trifolium repens) and the timing of species establishment (synchronous vs. sequential sowing) influenced the structuration of the recipient community and its resistance to invasion by A. artemisiifolia. Small differences in assembly history of the recipient community substantially affected community structure, biomass production, soil nutrient content, as well as early invasion resistance. Sequential sowing generally decreased invasion resistance compared with a synchronous sowing. Early colonizers generated priority effects of variable strength most likely via belowground competition, which affected A. artemisiifolia’s invasion success. A prior establishment of the N-fixing legume T. repens particularly boosted A. artemisiifolia’s performance. In conclusions, this thesis work highlights the inadequacy of revegetation strategies based on limiting similarity and reveals promising perspectives of manipulating assembly history and priority effects for designing invasion resistant communities. Assembly history significantly influenced early invasion success by inducing differences in biomass production and resource preemption by the recipient community. Priority effects of newly established communities and associated invasion resistance could be enhanced by (1) giving as much time advance as possible to the recipient community over invasives, (2) introducing species displaying an ability to rapidly produce biomass and preempt soil resources, or (3) avoiding sequential sowing especially when early colonizers are nitrogen-fixing, productive species
Abdelkrim, Jawad. "Structuration génétique de populations introduites de rats Rattus rattus (Berkenhout, 1769) et Rattus norvegicus (Linné, 1758) en milieu insulaire : l'outil génétique au service de l'étude des invasions biologiques et de l'aide à leur gestion." Paris 6, 2005. http://www.theses.fr/2005PA066175.
Zarzoso-Lacoste, Diane. "Vers une meilleure compréhension des interactions trophiques directes et indirectes entre prédateurs invasifs et espèces natives au sein des écosystèmes insulaires." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4330/document.
Introduced predators, particularly cats (Felis silvestris catus) and rats (Rattus spp) are recognized as a major factor of rarefaction and extinction of island bird species. The impact of predation on bird populations is usually assessed through the morphological identification of bird remains in predator diet samples. A review conducted in this thesis highlighted the qualitative and quantitative biases related to the difficulty of detecting and identifying the consumed bird species in predator diet samples. Molecular methods allow the accurate detection and identification of targeted prey DNA in the diet of predators. A large part of the work entailed here has been to optimize the molecular protocol and particularly the key steps of the selection of.taxon-specific primer pairs and the extraction of prey DNA. A comparative study of the performances of both morphological and molecular methods highlighted the strength of the latter in the detection and identification of the bird species preyed by cats and rats on Niau island (French Polynesia). The study of the direct (predation) and indirect (competition for food) trophic interactions between three invasive predators (R. exulans, R. rattus and F. s. catus) and a critically endangered bird, the Tuamotu Kingfisher (Todiramphus gambieiri), demonstrated a very low impact of cats and rats on the population of Tuamotu Kingfisher through predation, but a high potential for food competition between this bird and the two species of rats, particularly for lizards (Scincidae) and some terrestrial arthropods. Finally, management perspectives regarding the conservation of Kingfisher Gambier are proposed and discussed
Falardeau-Côté, Marianne. "L’invasion du lançon du Pacifique en mer de Beaufort : impacts sur la morue arctique et son écosystème." Thesis, Université Laval, 2014. http://www.theses.ulaval.ca/2014/30566/30566.pdf.
Climate change in the Arctic threatens hyper specialized polar species while favouring the invasion of boreal and temperate fish species. In the arctic marine food web, arctic cod (Boreogadus saida) is the key forage fish species. The boreal Pacific sand lance (Ammodytes hexapterus) was recently detected in southeastern Beaufort Sea (Canadian Arctic), numbering as the second most abundant ichthyoplankton species after the arctic cod in 2011. The aim of this research was to elucidate the consequences of this boreal forage fish species invasion on arctic cod during the early life stages. Potential competition was detected during the early juvenile stage but arctic cod strongly relied on big calanoid copepods while Pacific sand lance significantly selected for smaller prey. The forecasted reduction in the size of zooplankton would therefore favour sand lance over arctic cod. The interspecific competition is predicted to amplify as the abundance of sand lance in the Beaufort Sea increases.
Blard, Fabrice. "Les fourmis envahissantes de l'île de La Réunion : interactions compétitives et facteurs d'invasion." La Réunion, 2006. http://elgebar.univ-reunion.fr/login?url=http://thesesenligne.univ.run/06_13-blard.pdf.
Among the six most widespread and damaging invasive ants. Three are present in Reunion Island: Anoplolepis gracilipes, Pheidole megacephala and A. Gracilipes. This study focused on the competitive interactions among these three species and on the factors linked to their invasive success. These ants coexist in lowland anthropogenic habitats: P. Megacephala and S. Geminata were the two dominant species, the densities of their colonies varying with the climatic conditions, whereas A. Gracilipes was rare. They have never been observed in the sampled forests: the importance of the environmental conditions on the dominance of these invasive ants could explain this result. However the low ant species diversity in these habitats provides a niche opportunity for some other invasive ants
Bifolchi, Aline. "Biologie et génétique des populations d'une espèce invasive : le cas du vison d'Amérique (mustela vison Schreber, 1777) en Bretagne." Phd thesis, Université d'Angers, 2007. http://tel.archives-ouvertes.fr/tel-00346327.
Plantamp, Christophe. "Implication de la niche écologique et des indices environnementaux liés à la localisation de la ressource dans le succès invasif du ravageur Drosophila suzukii : des pistes pour le développement du piégeage massif." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1059/document.
In the last few decades, the development of international trade has seen resulting in an acceleration of intercontinental movements of species. These multiple introductions are the cause of many cases of invasion, where species are established and spread. In the new environment, studying factors related to the ecological niche help understanding what happens during the establishment of introduced species within the community resident species. The “empty niche hypothesis”, which predicted that the invasion is possible because a gap exists in the ecological niches of the resident community, is one of the facilitating factors of many cases of invasion. In addition, the strategy of utilization of the resource by the invasive species in the ecological niche may also explain the propensity of a species to invade or not the new environment. The objective of this thesis is to explore the significance of these assumptions in the invasive success, through the example of Drosophila suzukii. Introduced in 2008 in Europe and the US, this species has invaded every continent in less than 7 years. It is the only European species of fruit flies that can lay eggs inside healthy fruits, which are omnipresent, in an ecological niche free of any competitor. It is the cause of dreadful issues for grown fruit and is one of the major pests in production of berries. Better understand its invasion, its ecological niche and habitat selection strategy help better fighting the insect, including methods to disrupt the location of fruit in the environment. This applied context is also an important aspect of this thesis, funded also to optimize the fight by mass trapping
Blight, Olivier. "Ampleur et conséquences écologiques de l’envahissement du littoral corse par la fourmi d’Argentine (Linepithema humile, Mayr)." Aix-Marseille 3, 2010. http://www.theses.fr/2010AIX30049.
The Argentine ant, Linepithema humile, has spread with ease across many zones of the globe with a Mediterranean or subtropical climate, transported from its native range in South America mainly through trade at the end of the 19th century. Today, it is very densely represented in southwestern Europe, along the Portuguese, Spanish, French and Italian coasts. Despite its presence in Corsica for more than 50 years, little data is available on the causes and the consequences of the invasion. The present study therefore seeks to provide comprehensive information on three main axes of research on the Argentine ant, i. E. Its social structure, its distribution and expansion dynamics and how it affects native fauna and flora. As such, the aim here is to provide useful input for the management and control of invasive species. Our study confirms the invasiveness of the Argentine ant along the Corsican coast. Using behavioral, chemical and genetic analyses, we show that it is organized in two supercolonies in Corsica, one of which, the” Corsican” supercolony, constitutes a new entity for Europe. Exploring almost 80 coastal sites, we state the strong expansion of its distribution range over the last 10 years, fuelled by human activities. We also bring to light the resistance to invasion of a dominant native species, Tapinoma nigerrimum, using behavioral tests which may explain the mosaic distribution of the Argentine ant in Corsica. We show that Argentine ants have a major impact on native ants, being able to invade natural areas, and that they can bring about an almost 80% reduction in native community richness. Two factors may explain this ecological success: their wide space occupation, potentially allowing Argentine ants to maintain high competition pressure over the whole habitat, and their high interspecific aggressiveness, which can result in raids on native ant nests or columns. Finally, we studied the direct effect of the elimination of native ants on the seed dispersal of Anchusa crispa, a rare and threatened Corsican-Sardinian endemic species. Argentine ants disperse more seeds than native ants, reduce seed predation from native harvester ants and may facilitate seed germination. These results show for the first time that the Argentine ant can be beneficial to a native endemic plant. This work provides extensive information on the biology and ecology of the Argentine ant, contributes to the ongoing discussion on invasion biology and points towards new path of research
Andrade, Restrepo Martín. "Mathematical modeling and evolutionary processes." Thesis, Sorbonne Paris Cité, 2019. http://www.theses.fr/2019USPCC021.
The research presented in this thesis concerns different topics in the field of Biomathematics. I address diverse questions arising in biology (and related to complex systems) with mathematical and numerical methods. These questions are: (i) Are passive-processes enough to justify the asymmetric distribution of damaged proteins during and after yeast cytokinesis? (ii) What processes are behind the complex patterns of expansion of Amyloid beta in the brains of patients with Alzheimer’s disease? (iii) What is behind the clustering and cline-like dichotomy in models of evolution along environmental gradients? (iv) How does this dichotomy affect the spatial dynamics of invasions and range expansions? (v) How does multi-stability manifest in these models? These questions are approached (at different scales, some fully and some partially) with different theoretical methods. Results are expected to shed light on the biological processes analyzed and to motivate further experimental and empirical work which can help solve lingering uncertainties
Palmas, Pauline. "Ecologie et impacts d'un prédateur introduit au sein d'un hot-spot mondial de biodiversité : le chat haret Felis catus dans l'archipel néo-calédonien." Thesis, Nouvelle Calédonie, 2017. http://www.theses.fr/2017NCAL0006/document.
Feral cat (Felis catus) is one of the most successful and harmful invasive predator species for island biodiversity. The presence of this alien predator species generally lead to dramatic loss of native island biodiversity and represents a serious threat for numerous endemic and threatened species. Feral cats have invaded the whole New-Caledonian archipelago and all its habitats. In this study, we focused on the ecology and impacts of this invasive predator on the outstanding endemic fauna found in the different habitats of the exceptional New-Caledonia biodiversity hotspot. Feral cat diet analyses on 14 selected sites representing the 4 main natural habitats revealed a high diversified diet and high predation rates on native species particularly on squamates, flying foxes and petrels. Among the 44 vertebrates species found into the feral cat diet, 20 are IUCN red-listed threatened species. Cat movements of eleven feral cats fitted with GPS collars have been studied in a western coast Peninsula hosting an important seabird colony. Male cats showed large home ranges while female showed small home ranges. Feral cats exhibited important movements within the studied peninsula linked with the breeding cycles of seabirds. GPS data coupled with dietary informations suggested a predation that concerned both breeding adults and fledgings bird, and at a large geographic scale as some feral cats have their core home range distant to the colony (>3km). We evaluated the effects of a high level but intense cat control on this site that showed a low sustainability of feral cat culling and a rapid recolonization process. Our results are pleading for the future limitation of feral cat impacts and call to focus first abundance limitation measures on maquis mosaic and humid forest habitats This study also provided information on the spatial extent and intensity of future control measures in the special context of a large and highly invaded island
Barrios, Barri Oriol de. "Role of ZEB1 in Tumor Progression: Regulation of Cell Invasion and Senescence." Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/401707.
Els factors de transcripció ZEB (ZEB1 i ZEB2) son àmpliament coneguts pel seu paper en la transició epitelial-mesenquimal (EMT). A través d’aquest procés, les cèl·lules perden les característiques que les defineixen com a epitelials i adquireixen marcadors mesenquimals, augmentant així la seva capacitat invasiva. Tot i això, recentment s’ha descrit que els factors ZEB tenen funcions més enllà de l’EMT, com ara la resistència a la quimioterapia, que promouen la progressió tumoral. En el cas del càncer colorectal (CCR), s’ha descrit que ZEB1 és activat per la via de senyalització de Wnt, activa en un 80% dels casos. En conseqüència, ZEB1 s’expressa en les cèl·lules invasives del front tumoral. Tenint en compte aquests antecedents, l’objectiu general de la Tesi ha estat el de caracteritzar nous mecanismes a través dels quals ZEB1 regula la transformació oncogènica i la progressió tumoral en CCR, més enllà de la inducció de l’EMT. Els objectius específics han estat: 1) descriure el paper de ZEB1 en la regulació de les etapes inicials d’invasivitat, com la remodelació de la matriu extracel·lular; 2) identificar nous gens diana de ZEB1 al front tumoral de CCR, així com caracteritzar la rellevància d’aquestes dianes in vivo; i 3) identificar processos comuns a tots els tipus de càncer que puguin estar regulades per ZEB1 en la progressió del CCR. Els resultats es presenten com a compendi de publicacions. En el primer dels articles (Clin Cancer Res, 2013. 19(5):1071-82), es descriu el paper de ZEB1 en la regulació oposada dels membres del sistema activador del plasminogen (uPA i PAI-1). Aquesta regulació promou la migració de les cèl·lules a través de la matriu extracel·lular. En el segon dels articles (Gut, 2016. doi:10.1136/gutjnl-2015-310838), s’ha identificat un nou mecanisme a través del qual ZEB1 està inhibint l’entrada de les cèl·lules tumorals a l’estat de senescència, un conegut mecanisme supressor tumoral. ZEB1 activa l’inhibidor de la via Wnt DKK1, desencadenant l’activació d’una ruta de senyalització que implica a p53 mutat, MDM2 i CtBP. Aquest darrer coopera amb ZEB1 en la repressió de la histona macroH2A1, clau en la inducció de la senescència.
Merceron, Nastasia. "Processus écologiques et évolutifs impliqués dans le succès de l'introduction de Quercus rubra L. en Europe." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0263/document.
Northern Red Oak (Quercus rubra L.) is a tree native to North America and introduced in Europe at the end of the 17th century as an ornamental and forestry species. The aim of this dissertation is to understand the ecological and evolutionary mechanisms contributing to its dynamics and success in Europe. We demonstrated that this species naturalized and planted insome European countries can easily naturally grow in deciduous and conifer forests. Acorn dispersal away from mother-trees was made possible by scatter-hoarding animals such as squirrels and mice that take away acorns, although the animals still preferred acorns of the native oak Q. robur. During species introduction in a new environment, evolutionary processes can occurand lead to phenotypic and genetic changes. A comparative analysis of the genetic structure and diversity of Q. rubra populations from the native and introduced ranges demonstrated that onlytwo of the three genetic clusters encountered in North America are currently present in Europe.No strong bottleneck event was detected during the introduction of Q. rubra populations in Europe suggesting that multiple introductions could have maintained genetic diversity in introduced populations. A comparative analysis of phenotypic traits showed that introduced populations of Q.rubra present a higher growth compared to that of native populations. A genetic differentiation within European populations is on going regarding phenology of leaf budburst suggesting apossible rapid adaptive evolution since introduction
Drouin, Annick. "Établissement et impacts de la macroalgue non indigène « Codium fragile ssp. fragile » dans les herbiers marins aux îles de la Madeleine." Thesis, Université Laval, 2013. http://www.theses.ulaval.ca/2013/29902/29902.pdf.
Biological invasions are recognized as an important threat to ecosystems, in particular for coastal ecosystems. Native of Asia, the green seaweed Codium fragile ssp. fragile (synonymous of ssp. tomentosoides, herafter Codium) was first observed in eastern Canada in 1989 and has since been proliferous along the coasts of the southern Gulf of the St. Lawrence. This alga is known to establish on rocky shores, but it has recently been observed colonizing soft bottom habitat also, in particular forming dense canopies on eelgrass (Zostera marina) rhizomes. The main objective of this thesis was to identify the impacts of Codium establishment on eelgrass beds of the îles de la Madeleine. The study of Codium recruitment has shown that population expansion is possible within the studied eelgrass beds, but the colonization was rather low. Moreover, the success of Codium establishment in eelgrass beds varied spatially. Where Codium can reach a high biomass, An in situ experiment revealed that areas with high biomass of Codium can negatively effect eelgrass density and carbohydrate storage in rhizomes. A possible cause for these observations could be the shading created by algal cover, affecting clonal growth by eelgrass as well as influencing the plants allowance of energy. However, these effects were not detectable in naturally invaded beds. As shown, negative effects on eelgrass beds only occured when Codium biomass was high, an infrequent phenomenon that varied annually in the naturally invaded beds. It was also shown that thalli of Codium offer a distinctly different habitat than eelgrass shoots, resulting in more diverse and abundant epifauna on Codium. At a larger scale, the presence of Codium in eelgrass beds was found to influence fish distributions, by promoting higher density of certain species. However, no adverse effects were detected on native fauna.
Lejart, Morgane. "Étude du processus invasif de Crassostrea gigas en Bretagne : état des lieux, dynamique et conséquences écologiques." Brest, 2009. http://www.theses.fr/2009BRES2026.
The Pacific oyster, Crassostrea gigas, was introduced in France at the end of the sixties to replace the Portuguese oyster, Crassostrea angulata, decimated by disease. But only since the nineties that wild populations established on Brittany’s shores. The first part of this study shows ail Brittany coasts now to be colonized by C. Gigas. Stocks of wild oysters are estimated at 10000 and 6420 tons in the Bay of Brest, and the Morbihan Bay, respectively. The second part of this study concerns factors determining C. Gigas invasive process dynamics. The responsibility of climate change in the establishment of C. Gigas in Brittany is confirmed. Results also highlight that C. Gigas does not recruit in the subtidal zone, which refutes accusations of European oyster, Ostrea edulis, exclusion. Finally, monitoring of the summer 2008 massive mortalities reveals that wild populations were little impacted. Analysis of ecological consequences of C. Gigas invasion on Brittany shores is done in the last part of this study. Impacts on communities become marked when colonization intensifies with the creation of oyster reefs, which Increase macrofaunal abundance and diversity. Studies on respiration and calcification processes show that total annual carbon production of rocky intertidal communities is increased twenty fold, reaching 761,77 g C m-2 year-1 when high density populations of C. Gigas establish (nearly 700 ind. M-2)
Bardon, Clément. "Inhibition biologique de la dénitrification (BDI) par des métabolites secondaires du complexe d’espèces Fallopia spp." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10308/document.
Nitrogen is often considered as the first limiting factor of plant growth (Vitousek & Howarth, 1991a; LeBauer & Treseder, 2008). Thus studies on plant-driven microbial functioning and selection by secondary metabolites have mostly focused on the effect of plant on the nitrogen (N) cycle (Chapman et al., 2006). Some plants can inhibit the nitrification and the nitrogen mineralization processes in soils through the release of secondary metabolites (Subbarao et al., 2009; Dietz et al., 2013; Heumann et al., 2013). However, while denitrification is considered as a major way of N losses in soils (25-90%) (van der Salm et al., 2007; Radersma & Smit, 2011), the denitrification inhibition by plant secondary metabolites was never demonstrated. However, it has been observed several times that the denitrification in soils near some species was reduced. The invasive complex species Fallopia spp. was shown to reduce denitrification in soils without affecting principal factors known to control this process (Dassonville et al 2011). Our, results demonstrate for the first time, that plants (here Fallopia spp.) can inhibit denitrification through the release of B-type procyanidins that induce physiological changes in denitrifying bacteria under anaerobic conditions. These compounds affect specifically the membrane-bound NO3-reductase through conformational changes. Less sensitive soils denitrifying communities may be selected in soils previously exposed to Fallopia spp. Our finding provides new insight into plant-soil interactions and improves our understanding of plants abilities to shape microbial soil functioning
Fletcher, David. "Biological invasion risk assessment, considering adaptation at multiple scales : the case of topmouth gudgeon Pseudorasbora parva." Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTG029/document.
In this thesis I set out to quantify the risk of invasion from the invasive freshwater fish, Pseudorasbora parva, at a global extent, using traditional correlative ecological niche modelling approaches with the integration of surrogate data representing introduction likelihood (Chapter I). These correlative approaches rely upon key assumptions relating to the presence or absence of local or regional adaptations, and so I subsequently tested for evidence of such adaptations in genetic lineages and in individual populations. This was achieved through analyzing climatic niche differentiation of key genetic lineages in the native and invasive ranges (Chapter II) and by conducting lab experiments comparing thermal responses of important life history traits in populations from contrasting climates (Chapter III). The initial risk assessment did not account for a key factor in invasions; namely, natural dispersal. Natural dispersal has been observed to be subject to selection in vanguard populations of invasive species, and adaptation of dispersal traits can infer additional invasive vigor, allowing the species to spread across the landscape quicker. For this reason, I quantified dispersal, activity and morphological differences, often associated with differential dispersal ability, in populations along a distance-gradient from an invasion front, in order to identify if P. parva is capable of such adaptations.The initial risk mapping study showed that large areas, beyond the current distribution of the species, are climatically suitable. These areas are mainly in North and South America, Australia and New Zealand, and constitute significant scope for spread and impact of this species. When introduction likelihood was included, N. America appears most at risk. I found no evidence to suggest that native genetic lineages represented local adaptations to their respective native climates - there was little or no differentiation of the lineages’ climatic niches in the invasive range. It was also apparent, from the niche comparisons, that the climatic niche in the invaded range constituted a significant shift, compared to the native range. The thermal responses of P. parva life history traits did not differ significantly between populations from a strongly seasonal continental climate and a mild temperate maritime climate. The overall reproductive output of females did not vary according to breeding season temperature, however, temporal reproductive strategy showed a strong response, with lower temperatures inducing a protracted breeding season and higher temperatures inducing rapid and intense reproductive output. The dispersal and morphology-related study identified a strong gradient of morphological change, corresponding with distance from invasion front. This demonstrates a high degree of plasticity in P. parva’s morphology in an invasion context, however this was not linked to either dispersal or activity levels, neither of which was significantly linked to distance from invasion front. Dispersal was best explained by body size, with larger fish more likely to disperse further.Whilst I found no evidence to suggest that the model predictions (Chapter I) were hampered by differentiation at either lineage or population levels, the findings of Chapter II do highlight the uncertainties surrounding the degree of conservatism in such predictions, mainly owing to the fact that past, native, distribution did not accurately predict the current invaded distribution. The results of Chapters II-IV show broad tolerances and great plasticity in P. parva, which likely underpin this species success as a pan-continental invader. The knowledge produced in this thesis provides a useful new resource for the development of management strategies for P. parva and could be usefully enhanced by the additional of analogous studies on native populations, which could help elucidate the source of the observed plasticity
Rey, i. Planellas Sònia. "Biologia, ecologia i efectes de la formiga invasora Lasius neglectus (Hymenoptera, Formicidae) en comunitats d'artròpodes." Doctoral thesis, Universitat Autònoma de Barcelona, 2007. http://hdl.handle.net/10803/3681.
Pels estudis sobre la seva biologia reproductiva es va constatar el seu caràcter poligínic en tota la supercòlonia, amb una gran densitat de reines per supercolònia que es trobaven isolades o bé en grups de 2 o més reines dins de cada niu i sempre amb obreres. Per les dades en increment en pes sec i contingut de greixos des del naixement fins al moment de l'aparellament es va demostrar que les reines de L. neglectus es poden reproduir mitjançant fundació dependent tot i que el valor obtingut de la proporció del mesosoma de reines i obreres (relació entre el volum del tòrax de reines i obreres=23.83±0.15) coincideix amb el de les espècies que fan fundacions independents. Al laboratori també es van obtenir obreres a partir de reines joves acabades de fecundar (fundacions independents, haplo i pleometrótiques). Per les dades en contingut de carbohidrats es demostra que les reines tenen valors entremitjos entre les reines d'espècies que fan vols nupcials i les que no són capaces de volar, tot i que per l'àrea relativa de les ales les reines de L. neglectus han de ser capaces de volar. Tanmateix mai s'ha documentat cap vol nupcial en L. neglectus fins ara. Les reines joves alades fan fecundació intranidal i aquestes reines joves fecundades són adoptades per les reines velles i les obreres dins del mateix niu. Aquesta estratègia evita la depredació de reines joves fecundades després del vol nupcial, moment crític per a l'expansió de la colònia o la dispersió de l'espècie. Per tant aquesta expansió és per gemmació o bé a través de transport passiu, normalment afavorit per l'home. Les taxes de posta de reines velles són el doble que les de reines joves, amb un temps mitjà de desenvolupament de les obreres, però, el doble de llarg.
L'efecte més significatiu de la invasió de L. neglectus, tant a nivell d'abundància com de riquesa d'espècies, es va trobar sobre la resta de formigues natives. En totes les poblacions estudiades la presència de L. neglectus reduïa significativament la probabilitat de trobar espècies de formigues natives tant al sòl com als arbres. En el cas de l'efecte sobre altres artròpodes els resultats eren més variables: alguns artròpodes com ara els àfids es veien afavorits per la seva presència i en canvi altres ordres com ara Aràcnids, Himenòpters i Dípters es veien afectats negativament per la presència de la formiga invasora. Tanmateix aquests efectes, tant en formigues natives com en altres artròpodes, variaven en funció de la població estudiada i depenent de l'hàbitat mostrejat: capçades dels arbres o bé sòl.
En quan a les mesures per controlar aquesta invasió, es va fer un assaig amb insecticides d'una colònia de L. neglectus. Es van atacar tots els fronts possibles d'expansió de la invasió: a) l'interior de cases ocupades amb esquers, b) el perímetre de les cases ocupades amb injeccions amb un insecticida de contacte amb gran persistència al igual que c) els troncs dels arbres i finalment, d) es van tractar totes les capçades dels arbres de la zona ocupada per tal de matar els àfids, que són el principal aliment de L. neglectus. Gràcies al coneixement de les dades biològiques i ecològiques de la supercolònia de L. neglectus el resultat d'aquests tractaments integrats va ser satisfactori ja que disminuïa dràsticament la probabilitat de trobar formigues després del tractament i, a l'any següent al tractament, els nivells inicials de formigues eren molt menors als de l'any abans de tractar. Els tractaments es van fer dos anys seguits amb resultats prometedors i gran satisfacció per part dels habitants de les cases ocupades.
The aim of this work is to study: a) the reproductive biology and ecology of the invasive garden ant Lasius neglectus and b) its effects over other native arthropod communities in invaded communities from Northeast Spain; this last aspect has been studied on three populations. A large scale insecticide treatment of the plague was also made with contact and high persistence insecticides.
Its polygynic character was ascertained by the studies about its reproductive biology, with a great density of queens that were found isolated or in groups of 2 or more queens per nest, always with workers. From data obtained in increase in dry weight and fat contents from eclosion until mating time, it was demonstrated that L. neglectus queens can reproduce through dependent colony founding even though the value obtained from the proportion of the mesosome ratio from queens and workers (queen/worker thorax volume=23.83±0.15) coincides with the independent colony founding species. Workers were also obtained, at the laboratory, from newly mated queens (haplo- and pleometrotic independent foundations). From data in carbohydrate content, queens have intermediate values among the flying queens and those not capable to perform nuptial flights, even though for the relative area of the wings, L. neglectus queens are capable of flying. However it has never been documented a nuptial flight in L. neglectus until now. Queens reproduce by intranidal mating and these fertilized young queens are adopted by the old queens and workers into the same nest. This strategy avoids the possible predation of young fertilized queens after the nuptial flight, a critical moment for the expansion of the colony. Therefore they expand by budding or through passive human transport. The egg laying rates of old queens are two fold than that of young mated queens, with a total development time from egg to worker double than from egg to nanitic for young queens.
The most significant effect of the invasion of L. neglectus, on native arthropods abundance and species richness, was on coexisting native ants. In all the studied populations the presence of L. neglectus reduced dramatically the likelihood of finding native ants on tree canopies and soil. For the effect of L. neglectus on other non-ant arthropods the results were more variable: some arthropods like aphids were favoured by its presence and other orders as Arachnids, Hymenoptera and Diptera were negatively affected for the presence of the invading ant. However these effects, in native ants as well as in other arthropods, vary depending on the studied population and on the sampled habitat: tree canopy or soil surface.
In order to control this invasion, classical treatments with insecticides were applied to one of the supercolonies studied. All the possible expansion fronts of the invasion were attacked with a) an in-house baiting, b) a house perimeter injection treatment, c) tree trunk spraying, and finally d) canopy fogging in order to kill the aphids, which are the main food supply for L. neglectus. Thanks to the knowledge of the biological and ecological features of the supercolony of L. neglectus the results of these integrated treatments were satisfactory. They drastically reduced the probability of finding ants after the treatment and, for the next year after the first treatment, the initial ant levels were lower than those of the year before treating. This treatment was repeated for two years with promising results and great satisfaction of the homeowners.
Javal, Marion. "Invasion du capricorne asiatique Anoplophora glabripennis : génétique, traits d’histoire de vie et écologie." Thesis, Orléans, 2017. http://www.theses.fr/2017ORLE2034/document.
The Asian longhorned Beetle Anoplophora glabripennis provides a good example of insects that benefited from international trade from Asia. It partly invaded North America, where it has been present since the 1990s, and Europe where its presence was detected in the early 2000s. This highly polyphagous species develops in urban trees and can cause their death, highlighting the importance of its management. The aim of this thesis was to use a multidisciplinary approach to study the invasion of A. glabripennis in order to bring new elements to the global understanding of biological invasions. I therefore first wanted to retrace its invasion route through the world. Secondly, I sought to know whether some of its biological characteristics had contributed to the success of its invasion. Finally, I addressed the question of the ecological impact of A. glabripennis by focusing on the alterations of the xylophagous fauna that its presence could have caused. The results obtained in this thesis revealed a complex invasion which includes several introductions as well as a bridgehead scenario between North America and Europe. It also appeared that some traits of the species contributed to shaping its distribution pattern. Notably, its resistance to thermal stress probably favored its installation in various climates. Furthermore, the natural dispersion of A. glabripennis seems very limited, but my results indicated that the species is not limited by its physiological capacities to disperse. Finally, the preliminary study of the invaded fauna did not reveal any effects of the species on the other Ceramycidae for the moment. In the light of the other cases of invasion documented, the case of A. glabripennis highlights the diversity of the characteristics of species becoming invasive, and confirms the difficulty of drawing a typical portrait
Böhme, Katja [Verfasser], and Petra [Akademischer Betreuer] Dersch. "Identification and characterization of regulatory factors and regulatory RNA elements controlling the expression of the primary invasion factors invasin and YadA in Yersinia pseudotuberculosis / Katja Böhme ; Betreuer: Petra Dersch." Braunschweig : Technische Universität Braunschweig, 2010. http://d-nb.info/117582514X/34.
Hammann, Sven [Verfasser]. "Invasion Biology of Mnemiopsis leidyi and its symbionts / Sven Hammann." Kiel : Universitätsbibliothek Kiel, 2012. http://d-nb.info/1029293422/34.
Enders, Martin [Verfasser]. "Creating and evaluating hypothesis networks in invasion biology / Martin Enders." Berlin : Freie Universität Berlin, 2020. http://d-nb.info/1205314857/34.
Hammann, Mareike [Verfasser]. "Invasion ecology of marine macroalgae : the relevance of stress resistance for the invasion success of Gracilaria vermiculophylla and consequences of its spread / Mareike Hammann." Kiel : Universitätsbibliothek Kiel, 2018. http://d-nb.info/1153768542/34.
Gilbert, Mark. "Modelling species invasions in heterogeneous landscapes." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:944d15d3-257a-47e5-acb9-9bdfba26985b.
Gichohi, Nathan W. "Ecological impacts of biological invasions on native birds in Africa." Master's thesis, University of Cape Town, 2010. http://hdl.handle.net/11427/4747.
Scheetz, Emily. "Erythrocyte Biology and its Impact on Plasmodium vivax Invasion." Cleveland, Ohio : Case Western Reserve University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=case1216148822.