Tesis sobre el tema "Introduced animals"
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Keplinger, Brandon J. "An experimental study of vertical habitat use and habitat shifts in single-species and mixed-species shoals of native and nonnative congeneric cyprinids". Morgantown, W. Va. : [West Virginia University Libraries], 2007. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5163.
Texto completoPercival, Scott R. "Feeding and substrate preferences of the Japanese shore crab, hemigrapsus sanguineus /". View abstract, 2002. http://library.ccsu.edu/ccsu%5Ftheses/showit.php3?id=1662.
Texto completoThesis advisor: Kim Wilson. " ... in partial fulfillment of the requirements for the degree of Master of Science in Biology." Includes bibliographical references (leaves 54-58). Also available via the World Wide Web.
Cassey, Phillip y n/a. "Comparative Analyses of Successful Establishment Among Introduced Land Birds". Griffith University. Australian School of Environmental Studies, 2002. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20030915.094001.
Texto completoFraser, Elaine J. "An integrative approach to inform invasive species management : the case of American mink (Neovison vison) in West Scotland". Thesis, University of Aberdeen, 2013. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=206603.
Texto completoCarne, Vanessa L. "Ecology of Mediterranean snails in Southern Australian agriculture : a study of Cernuella virgata and Cochlicella acuta on the Yorke Peninsula /". Title page, table of contents and summary only, 2003. http://web4.library.adelaide.edu.au/theses/09PH/09phc2891.pdf.
Texto completoGross, Lee M. "Long-term assessment of predatory fish removal on a pond-breeding amphibian community in central Illinois /". View online, 2009. http://repository.eiu.edu/theses/docs/32211131565136.pdf.
Texto completoPiola, Richard Fabio Biological Earth & Environmental Sciences Faculty of Science UNSW. "Differential tolerance of introduced & native marine invertebrates to heavy metal pollution". Publisher:University of New South Wales. Biological, Earth & Environmental Sciences, 2007. http://handle.unsw.edu.au/1959.4/40673.
Texto completoKasper, Marta L. "The population ecology of an invasive social insect, Vespula germanica (Hymenoptera : vespidae) in South Australia /". Title page, table of contents and abstract only, 2004. http://web4.library.adelaide.edu.au/theses/09PH/09phk1928.pdf.
Texto completoKim, Gene Wook. "Trophic transfer of energy and polychlorinated biphenyls by native and exotic fish in Lake Erie". Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1174664048.
Texto completoHewitt, Chad LeRoy. "Marine biological invasions : the distributional ecology and interactions between native and introduced encrusting organisms". Thesis, Thesis (Ph. D.)--University of Oregon, 1993, 1993. http://hdl.handle.net/1794/9974.
Texto completoMercado, Alida. "Ground beetle (Coleoptera:Carabidae) communities along a successional gradient in southwestern Quebec and notes on the range expansion of introduced species". Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=97966.
Texto completoMiller, Anna Aroha y n/a. "Enemy escapee or trojan horse? : investigation of the parasite burdens of native and introduced marine crabs and bivalves in New Zealand". University of Otago. Department of Zoology, 2007. http://adt.otago.ac.nz./public/adt-NZDU20080131.092837.
Texto completoSheffels, Trevor Robert. "Status of Nutria (Myocastor coypus) Populations in the Pacific Northwest and Development of Associated Control and Management Strategies, with an Emphasis on Metropolitan Habitats". PDXScholar, 2013. https://pdxscholar.library.pdx.edu/open_access_etds/665.
Texto completoSievers, Caya. "Enemy within the gates : reasons for the invasive success of a guppy population (Poecilia reticulata) in Trinidad". Thesis, University of St Andrews, 2010. http://hdl.handle.net/10023/1865.
Texto completoEscoriza, Daniel. "Factors regulating the invasion of two Mediterranean anurans. The role of niche conservatism, species interaction and habitat selection". Doctoral thesis, Universitat de Girona, 2015. http://hdl.handle.net/10803/300902.
Texto completoEls amfibis són un grup en declivi a nivell mundial. Els factors que estan causant aquest declivi no són coneguts, però podria ser multifactorial, en relació amb l'expansió recent de certs patògens i les alteracions dels hàbitats. Un d'aquests factors que es relacionen amb la pèrdua de qualitat dels hàbitats és la introducció d'espècies exòtiques. Aquestes espècies poden competir o depredar sobre les espècies de la comunitat recipient, produint profundes alteracions en l'estructura d'aquestes comunitats. Per aquesta raó és prioritari conèixer que factors actuen facilitant el procés invasiu i quines espècies es poden veure més afectades per la presència d'una espècie exòtica. A Catalunya s'ha establert una espècie de anur d'origen africà, la granota pintada. Introduïda a l'extrem sud de França a inicis del segle XX, aquesta espècie s'ha anat expandint de forma progressiva, fins a arribar pel sud al delta del Llobregat i pel nord el Llenguadoc. Aquesta regió és rica en espècies natives d'amfibis, algunes d'elles endèmiques, i per tant cal conèixer com interacciona aquesta espècie recent arribada amb cadascuna d'aquestes espècies. Nosaltres hem utilitzat un enfocament nou en el moment d'analitzar aquestes interaccions, aplicant la teoria dels morfoespais. El morfoespai és el rang de variació morfològica que s'observa dins d'un acoblament. Aquesta morfologia es correlaciona amb l'ús d'un nínxol, i per tant les analogies morfològiques entre l'espècie invasora i les espècies natives poden servir com una aproximació per valorar el solapament funcional. Aquestes analogies en el morfoespai s'han avaluat també en l'area nativa de l'espècie i entre altres espècies de Discoglossus. La pregunta formulada és "ocupa l'espècie invasora un nínxol vacant, mantenint una distància morfològica similar que a l'acoblament d'origen i que altres espècies del gènere Discoglossus?".
Harper, Kirsten Jennifer. "Trophic niche and detection of the invasive signal crayfish (Pacifastacus leniusculus) in Scotland". Thesis, University of Stirling, 2015. http://hdl.handle.net/1893/22355.
Texto completoCasso, Carrasco Maria. "Genomic analysis of an introduced ascidian and implications for invasiveness". Doctoral thesis, Universitat de Barcelona, 2020. http://hdl.handle.net/10803/673998.
Texto completoDíez, del Molino David. "Genetic diversity and population structure of the non-native Eastern mosquitofish (Gambusia holbrooki) in Mediterranean streams". Doctoral thesis, Universitat de Girona, 2015. http://hdl.handle.net/10803/300440.
Texto completoLa gambúsia és un peix molt voraç i fecund originari de les masses d’aigua dolça del nord-est d’Amèrica, que va a ser introduïda en tot el món pel control biològic de les poblacions de mosquit. En aquesta tesis se analitzen els processos genètics relacionats amb l’èxit invasor de la gambúsia (Gambusia holbrooki) en les conques mediterrànies. Les poblacions de gambusia introduïdes catalanes mantenen els nivells de diversitat genètica presents a les poblacions Americànes que van ser les fonts dels invasors de Europa. En aquestas poblacions introduïdes, els nivells locals i patrons hidrogràfics de diversitat genètica es mantenen entre generacions. Hi a una resposta selectiva als contaminants en les poblacions de gamusia a l’embassament de Flix, riu Ebro, però aquestes pertorbacions humanes no limiten la dispersió de la gambúsia. Finalment, les translocacions d’exemplars per l’home augmenten les oportunitats de colonitzar nous ambients i per això han de ser controlats.
Richardson, Michael John. "Factors limiting the colonization success of an introduced exotic fish (Carassius auratus)". Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=40235.
Texto completoTests for assortative shoaling between brown and gold coloured morphs showed that gold coloured fish exhibited no colour based assortive shoaling, while brown fish showed slight but significant colour preferences for like-coloured fish. This level of shoaling preference did not improve after visual exposure or interaction with native predators, indicating that goldfish showed limited behaviourial responses to predators, and that they were unable to modify their response to a predation threat. Further trials allowing goldfish to interact with either pike (Esox lucius) or bass (Ambloplites rupestris), in both single species groups of predator-naive goldfish, and mixed species conditions of goldfish with predator-experience minnows, showed that goldfish did not alter their behaviour in the presence of minnows (Pimephales notatus) when the predators were not present. However, with the predators present goldfish altered their activities to a more minnow-like pattern and showed a significant improvement in anti-predator behaviour. This improved behaviour continued by goldfish when they were retested on their own, indicating that the goldfish were reacting to the predator and not the minnows. Goldfish colonization may therefore be limited not so much by predation or competition from native cyprinids, but more by the absence/presence of a suitable, native, predator-experienced fish from which to copy the appropriate anti-predator behaviours.
Burrows, Ben Robert. "Do Severe Genetic Bottlenecks Lead to Greater Reproductive Failure?" Thesis, University of Canterbury. Biological Sciences, 2006. http://hdl.handle.net/10092/1344.
Texto completoJacobs, Evert Philippus. "Diet and feeding effects of introduced giraffe in the Eastern Cape". Thesis, Nelson Mandela Metropolitan University, 2008. http://hdl.handle.net/10948/964.
Texto completoOlds, Alexis Amy. "The ichthyofauna of the Wilderness Lakes System, Western Cape, with particular emphasis on alien fish species and their establishment success". Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1005132.
Texto completoParker, Daniel Matthew. "The feeding biology and potential impact of introduced giraffe (Giraffa camelopardalis) in the Eastern Cape Province, South Africa". Thesis, Connect to this title online, 2004. http://eprints.ru.ac.za/48/.
Texto completoKataria, Mitesh. "Environmental valuation, ecosystem services and aquatic species /". Uppsala : Dept. of Economics, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/200765.pdf.
Texto completoPineda, Torres Mari Carmen. "A global wanderer: Biology, phylogeography and resilience of the introduced ascidian "Styela plicata" / Història d’una introducció global: biologia, filogeografia i susceptibilitat a factors ambientals de l’ascidi cosmopolita "Styela alicata"". Doctoral thesis, Universitat de Barcelona, 2012. http://hdl.handle.net/10803/101200.
Texto completoLa ascidia Styela plicata ha sido introducida alrededor del mundo y parece presentar las características necesarias para convertirse en invasora. El objetivo principal de esta tesis Doctoral ha sido incrementar nuestro conocimiento sobre la composición genética de la especie, sus características reproductoras y su habilidad para tolerar condiciones estresantes como adulto pero también a lo largo de las primeras etapas del cliclo de vida. Los resultados han indicado que S. plicata es una introducción antigua, dado que la especie ha estado viajando alrededor del mundo durante los últimos siglos gracias al transporte marítimo. Esta especie habita en puertos, marinas y otras estructuras artificiales, y tolera altas concentraciones de contaminantes. Los adultos pueden responder a niveles moderados de estresores ajustando la producción de proteínas de estrés, pero los primeros estadios del desarrollo son mucho más vulnerables a las condiciones que caracterizan los ambientes en que la especie habita. Un periodo reproductor extenso permite a la especie explotar ventanas temporales de condiciones favorables y confiere a la especie una ventaja competitiva frente a otros organismos con reproducción estacional. Además, la elevada variabilidad genética y la presencia continua de larvas en la columna de agua, garantiza también eventos de reintroducción secundarios y por tanto la dispersión de la especie vía tráfico marítimo. Actualmente, la distribución de S. plicata parece estar limitada por temperaturas elevadas, bajas salinidades y otros factores aún por investigar tales como la competencia y la depredación. La dinámica de las escasas poblaciones en que la especie cohabita con comunidades nativas debería ser estudiada, para detectar los factores que regularían la dispersión de la especie afuera de los ambientes confinados en que actualmente la encontramos.
Tidwell, Kyle Scott. "Quantifying the Impacts of a Novel Predator: the Distinctive Case of the Oregon Spotted Frog (Rana pretiosa) and the Invasive American Bullfrog (Rana (Aquarana) catesbeiana)". Thesis, Portland State University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10259428.
Texto completoThe decline of the Oregon Spotted Frog (Rana pretiosa), a Pacific Northwest endemic now federally listed as threatened, has been attributed to several aspects of ecosystem alteration, primarily habitat degradation and loss. The introduced American Bullfrog (Rana (Aquarana) catesbeiana ) has been widely implicated in those declines, but the basis of that contention has been difficult to characterize. The bullfrog occurring at every site of recent Oregon Spotted Frog extirpation has focused concern about its impact.
Here, I present a suite of interconnected studies that examine the behavioral ecology of both species to better understand the potential for bullfrog-mediated Oregon Spotted Frog extirpation. I quantified Oregon Spotted Frog anti-predator behavior from the only known population successfully co-occurring with bullfrogs (Conboy Lake) and a population devoid of bullfrog impact (Big Marsh), and compared these behaviors to the predatory traits of the bullfrog. The initial study revealed that captive-reared individuals from the Oregon Spotted Frog population that has successfully co-occurred with bullfrogs respond faster to a predatory stimulus (measured as latency to response) than Oregon Spotted Frogs from a population not to exposed to bullfrogs. Subsequent field investigations of the approach distance allowed by a predator stimulus before taking evasive action (termed the flight initiation distance: FID) conducted with the Oregon Spotted Frog population co-occurring with bullfrogs first demonstrated that FID of recently metamorphosed bullfrogs is consistently greater than that of recently metamorphosed Oregon Spotted Frogs. Further, examination of FID across all post-metamorphic age classes of Oregon Spotted Frogs revealed that older frogs do not allow as close approach as recently metamorphosed Oregon Spotted Frogs. This age class shift in FID did not occur in the Oregon Spotted Frog population not exposed to bullfrogs. In the latter population, FID did not differ among age classes.
Since the bullfrog might be driving this age-based change in anti-predator behavior, I explored the variation in strike distance of bullfrogs from the site of co-occurrence in both the field and laboratory to determine the extent of overlap with Oregon Spotted Frog FID. I found that the bullfrog strike distance significantly overlaps the FID of all ages of Oregon Spotted Frogs from the bullfrog-free site but only that of youngest (recently metamorphosed) frogs at the site of co-occurrence. Older Oregon Spotted Frogs from the site of co-occurrence generally escaped at distances greater than the strike distance of bullfrogs.
I also collected > 880 bullfrogs from the site of co-occurrence and analyzed the stomach contents to assess their dietary trends. I found that bullfrogs consume Oregon Spotted Frogs at the site, but do not eat the larger (older) frogs. Moreover, the body size ratio between Oregon Spotted Frogs as prey and bullfrogs as predators suggests that nearly all of the adult size distribution of bullfrogs at Conboy would be incapable of preying on adult Oregon Spotted Frogs.
Collectively, these studies strongly suggest that bullfrogs have altered the escape behavior of Oregon Spotted Frogs at Conboy Lake and that most adult Oregon Spotted Frogs at Conboy may have a size-based release from predation by bullfrogs. Implicit in this finding is that bullfrogs may pose a real threat via predation to other Oregon Spotted Frog populations with which they might come into contact where the distribution of bullfrog body sizes differ substantially from that at Conboy Lake.
Voss, Joshua C. "Forage Adaptability Trials for Forage and Seed Production in Bolivia; Effect of 5 Herbicides on 7 Native Utah Forbs". BYU ScholarsArchive, 2006. https://scholarsarchive.byu.edu/etd/1121.
Texto completoKelley, Amanda. "The Effect of Temperature on Phenotypes of the Invasive European Green Crab: Physiologic Mechanisms that Facilitate Invasion Success". PDXScholar, 2013. https://pdxscholar.library.pdx.edu/open_access_etds/1004.
Texto completoSrean, Pao. "Understanding the ecological success of two worldwide fish invaders (Gambusia holbrooki and Gambusia affinis)". Doctoral thesis, Universitat de Girona, 2015. http://hdl.handle.net/10803/295975.
Texto completoAquesta tesi té com a objectiu contribuir a millorar la comprensió de l'èxit invasor d'aquests dos peixos (Gambusia affinis and G. holbrooki). Es van revisar quatre bases de dades d'Internet i la bibliografia per aclarir la seva història d’introducció i distribució geogràfica, establir les rutes d'introducció i analitzar els predictors del seu èxit invasor. Una meta-anàlisi de l'impactes ecològics de les gambúsies mostra principalment que l'impacte global és: i) similar per a les dues espècies; ii) clar i fort per a peixos, macroinvertebrats, amfibis, i alguns grups de zooplàncton i més variable per als tàxons de nivells tròfics més baixos i a nivell d’ecosistema; iii) general per al nombre d'agressions rebudes i la disminució de la densitat i la biomassa, però més variable per altres variables; i iv) altament heterogeni i dependent del context per una sèrie de característiques. Hem estimat la velocitat crítica de natació mitjana (Ucrit) de G. holbrooki com 14.11 cm s-1, que és inferior a la de molts altres peixos de mida similar i confirma que aquesta espècie és limnòfila i el seu èxit invasor parcialment s'explica per l'alteració hidrològica. No obstant això, vam demostrar que Ucrit i la taxa metabòlica màxima varien notablement amb la mida i el sexe dels peixos, amb valors molt més alts als mascles que a femelles del mateix pes, els quals deuen ser per tant menys vulnerables a cabals forts.
Esposito, Anaïs. "Etude des parasites de la faune piscicole introduite et autochtone de Corse". Electronic Thesis or Diss., Corte, 2024. http://www.theses.fr/2024CORT0005.
Texto completoWith 3,000 km of waterways, Corsica has a particularly dense and complex hydrographic network. This complexity is compounded by the complexity of current fish populations, which is the result of successive waves of species introductions into the island's rivers and reservoirs. Although Corsica's native fish fauna is poorly diversified (only four species), more than twenty introduced species have artificially increased this diversity since the end of the 19th century. The impacts of introduced species on aquatic ecosystems are multiple (e.g., competition, predation, habitat modification, genetic impacts) and among these, the co-introduction of pathogens, including parasites, is of particular concern and still too poorly documented. Moreover, it is interesting to approach this type of subject in an insular environment. The work presented here therefore aims to determine the composition of the parasitofauna of native and introduced fish in Corsica, to assess its richness, to determine whether transfers of parasites from introduced fish to native fish have occurred, and whether the parasites present are likely to have an impact in terms of animal or human health. Sampling campaigns were carried out on a selection of native species (Anguilla anguilla, Salmo trutta, Salariopsis fluviatilis and Atherina boyeri) and introduced species (Phoxinus minnows, Perca fluviatilis, Squalius cephalus and Gobio spp.), four of which were particularly targeted for their accessibility and the parasitological problems they presented. The work carried out enabled us to determine the composition of A. anguilla parasite communities in two lagoons on the eastern plain and, for the first time, in numerous watercourses throughout the island. In addition, this work has highlighted the presence throughout Corsica of invasive parasites: the Monogenea Pseudodactylogyrus bini and P. anguillae and the Nematoda Anguillicola crassus, as well as their maintenance and the increase in their prevalence and abundance in the Biguglia lagoon since the previous decade. These results demonstrate the value of monitoring invasive parasites. The study of S. trutta trout has enabled us to propose a specific determination of Gyrodactylus, which causes pathologies in certain Corsican populations. As for introduced species, work on Phoxinus has revealed the presence of four species in this genus on the island, with the first records of Phoxinus csikii and Phoxinus septimaniae. Parasites of minnows have been studied in Corsica for the first time, and the distribution of Monogenea (Gyrodactylus) has enabled us to trace the secondary introduction routes of their hosts. These results demonstrate the need for taxonomic clarity in parasitology, and the contribution of parasite studies to invasion biology. Although carried out on a small number of fish, the study of Perca fluviatilis parasites revealed the presence of two zoonotic parasites in this fish: the Nematoda Eustrongylides spp. and the Digenea Clinostomum complanatum, both reported for the first time in France, and likely to have an impact on wildlife and human health. These observations confirm the need for a systemic approach such as One Health to this type of problem. Less extensive data were also provided for the first time on the parasitology of other introduced species and those native to Corsica (S. fluviatilis, A. boyeri, S. cephalus and Gobio spp.)
Duron, Quiterie. "Rats invasifs et biodiversité native au sein des forêts denses humides de Nouvelle-Calédonie. : Eléments pour l’amélioration des stratégies de gestion". Thesis, Nouvelle Calédonie, 2016. http://www.theses.fr/2016NCAL0006/document.
Texto completoIntroduced rats (Rattus spp.) are one of the major invasive species threatening native biodiversity on islands worldwide. Twospecies, the black rat (R. rattus) and the Pacifie rat (R. exulans) are sympatric in New Caledonian rainforests, where questionsasto the feasibility and the utility of their control (i.e. local limitation of their abundance) for the conservation of nativebiodiversity remain unanswered. ln response to the lack of a conceptual framework for control projects, we fi rst conducted areview of invasive rat control operations in island natural areas worldwide. Then we sought to characterize and understand thepopulation dynamics of these two sympa tric rat species and the ir interactions with native biodiversity in the rainforest of MontPanié mountain. Lethaltrapping operations and capture-mark-recapture showed that black rats were more abundant thanPacifie rats. Diet analysis revealed that the two species consume both shared and unshared prey likely resulting in astrengthening and a broadening oftheir impacts on native biodiversity, relative to the impact that each species would haveal one. Rats consume a large quantity of fruits and seeds, invertebrates, and Squamates. However, birds, which often justify theimplementation of rat management projects, do not appear here to be one of the ir preferred prey, either as adults or throughnest predation. A potential positive rat impact on seed dispersal was a Iso highlighted through a comparison of seedgermination after seeds had passed through rat versus native frugivore digestive tracts. Finally, we propose lethal trappingstrategies to efficiently control invasive rat populations. A better understanding ofboth rat impacts in sympatric situations,and the link between rat density and the intensity of their effects on biodiversity would allow optimizing rat control strategieswhen eradication is not feas ible
Mulero, Stephen. "Développement d’outils d’écologie moléculaire pour un suivi intégratif des maladies transmises par les mollusques d’eau douce dans un contexte d’émergences et de changements globaux A Multiplex Rapid Diagnostic PCR (RD-PCR) approach for xenomonitoring of human and animal schistosomiases in a One Health context Genetic diversity and relationships of the liver fluke Fasciola hepatica (Trematoda) with native and introduced definitive and intermediate hosts Simultaneous genotyping of gastropods and their trematode parasites using Amplicon Sequencing Pre-zygotic isolation mechanisms between Schistosoma haematobium and Schistosoma bovis parasites: from mating interactions to differential gene expression". Thesis, Perpignan, 2020. http://www.theses.fr/2020PERP0023.
Texto completoGlobal changes, whether climatic or anthropogenic, have various consequences in human and animal health, as well as for worldwide ecosystems. One of the most important is the modification of geographical ranges of species and those of their associated pathogens. It is in this context that in recent years we have witnessed a resurgence in the emergence and re-emergence of infectious diseases around the world. While research efforts in this field are mainly focused on viral diseases, freshwater snail-borne diseases, that affect more than 1 billion peoples around the world, are also subject to these outbreaks, which have become frequent. However, the study of the dynamics of parasites associated with these diseases focuses primarily on the diagnosis and treatment of the definitive hosts, particularly humans. Such an approach does not prevent the transmission of these parasites to humans and even less prevent an emergence event, and the existing tools used to monitor these parasites in the environment are difficult to apply at large scale. This thesis work, therefore aims to provide a more environmental vision of the dynamics of these diseases. With the example of the emergence of urogenital bilharziasis in Corsica, we analysed this emergence by integrating the study of the life history traits of the tropical parasite in question, particularly its thermo tolerance, as well as the role of mollusc intermediate hosts and wild and domestic definitive hosts in the local maintenance of the parasite lifecycle. In a second step, we have developed environmental DNA diagnostic tools for the detection of molluscs hosts in the environment in order to identify areas at risk of emergence, as well as tools for intramolluscal detection of schistosomes to identify active sites of transmission, and thus allow the environmental monitoring of the actors of these diseases. To complete these approaches, we have developed a more generalised environmental metabarcoding tool to characterise freshwater mollusc communities and initiated the development of a similar tool for the characterisation of trematode communities, in order to study the interactions between these organisms. Lastly, we discuss the integration of all these elements into new control strategies against snail-borne diseases
Teullet, Marie. "Les espèces exotiques envahissantes et le droit de la mer : essai de qualification". Thesis, Paris 2, 2014. http://www.theses.fr/2014PA020038.
Texto completoAlien invasive species are a growing concern, but are they an object as any other in international law ? An invasive alien species is a living species which, by its mere presence in an ecosystem outside its natural range, causes deleterious effects which is not the case in its native ecosystem. Is the law of the sea equipped to meet this new threat ? The classification of its effects in international law, and more specifically the law of the sea, is as innovative as capital. The legal treatment of invasive alien species so far has been tied to the struggle for the conservation of biological diversity without wondering, in advance, what its classification is. What if alien invasive species are considered pollution ? Considering this hypothesis means studying instruments of international law, and more precisely those of the law of the sea, as well as marine pollution. If one can allow to identify invasive alien species as a source of pollution, it remains a new form of pollution that has never been recognized before by the instruments of international law : a biological pollution. This pollution, independent of those already existing in international law, implies the need to rethink the definition of marine pollution
Bedecarrats, Alain. "Les peuplements végétaux issus de l'ensemencement des pistes de ski dans les Alpes du Nord : structure et dynamisme". Grenoble 1, 1988. http://www.theses.fr/1988GRE10071.
Texto completoMendes, Filipa dos Santos. "The impact of introduced animals and plants on São Tomé seed-dispersal network". Master's thesis, 2017. http://hdl.handle.net/10316/82870.
Texto completoAs invasões biológicas são um dos principais impulsionadores da perda de biodiversidade em todo o mundo, sendo particularmente perturbadora para as ilhas oceânicas. Essas extinções de espécies implicam a perda de funções do ecossistema, como a dispersão de sementes por animais. Trabalhando no hotspot de endemicidade da ilha de São Tomé, utilizamos análises complexas de rede de última geração para avaliar o impacto de grandes dispersores introduzidos nas redes de dispersão de sementes, formadas por pequenos dispersores endêmicos. As comunidades insulares evoluíram sob baixa pressão seletiva de grandes vertebrados, filtrados pela barreira oceânica para a dispersão. Portanto, a integração de grandes dispersores em São Tomé é susceptível de ter grandes implicações para a dispersão de plantas nativas e introduzidas, modelando o recrutamento de plantas e o futuro das florestas nativas.Durante um ano, compilámos interações entre plantas e os dispersores das suas sementes, através de cinco métodos complementares de amostragem: observações diretas, revisão literária, questionários, análise de excrementos e conteúdos estomacais. Após a reconstrução da rede de dispersão, avaliámos se a origem dos dispersores (nativos vs. introduzidos) ou a largura da sua garganta afeta o seu papel enquanto dispersores de sementes, nomeadamente: número de plantas dispersadas, grau de seletividade (d'), “species strenght” e tamanho das sementes dispersadas. A rede de São Tomé revelou 419 interações entre 22 espécies de dispersores (12 aves, 2 morcegos, 1 cobra e 7 mamíferos não voadores) e 150 espécies de plantas. Duas das plantas mais frequentemente dispersadas, Cecropia peltata e Rubus rosifolius são espécies altamente invasoras. Cada método de amostragem revelou-se principalmente útil para um pequeno grupo de dispersores, fornecendo por isso informação altamente complementar. Os questionários provaram ser o método de amostragem que contribuiu com mais interações, seguido da análise de excrementos e de conteúdos estomacais. Os dispersores nativos e introduzidos não diferiram significativamente em nenhum dos três descritores topológicos analisados, no entanto os dispersores introduzidos tenderam a dispersar espécies com sementes maiores. Esta diferença deve-se especificamente à maior largura da garganta dos dispersores introduzidos. No seu conjunto, estes resultados apontam para um importante potencial perturbador dos dispersores introduzidos, ao alterarem a pressão seletiva em favor de espécies com sementes grandes. Estas diferenças no tamanho das sementes dispersadas não se refletiu contudo em diferenças na topologia das interações estabelecidas, alertando para a necessidade de considerar simultaneamente características biológicas na interpretação das redes de interações.
Biological invasions are a key driver of biodiversity loss worldwide being particularly disruptive on oceanic islands. Such species extinctions entail the loss of ecosystem functions such as seed dispersal by animals. Working in the endemicity hotspot of São Tomé Island, we used state-of-the art complex network analysis to evaluate the impact of large introduced dispersers on seed-dispersal networks formed by small endemic dispersers. Island communities have evolved under low selective pressure from large vertebrates, filtered by the oceanic barrier to dispersal. Therefore, the integration of large dispersers into São Tomé is likely to have large implications for the dispersal of native and introduced plants, shaping plant recruitment and the future of the native forests. During one year, we compiled interactions between plants and seed dispersers through five complementary sampling methods: direct observations, literary review, questionnaires, excrement analysis and stomach contents. After rebuilding the dispersion network, we evaluated whether the origin of the dispersers (natives vs. introduced) or the width of their throat affects their role as seed dispersers, namely: number of plants dispersed, degree of selectivity (d '), "Species strength" and seed size dispersed. The São Tomé network revealed 419 interactions between 22 dispersers species (12 birds, 2 bats, 1 snake and 7 non-flying mammals) and 150 plant species. Two of the most frequently dispersed plants, Cecropia peltata and Rubus rosifolius are highly invasive species. Each sampling method proved to be particularly informative for a small group of dispersers, and therefore their results are largely complementary. The questionnaires proved to be the sampling method that contributed with more interactions, followed by fecal and stomach content analysis. Native and introduced dispersers did not differ significantly in any of the three topological descriptors analyzed, however introduced dispersers tended to disperse species with larger seeds. This difference is largely explained by the larger gape width of the introduced dispersers. Altogether, these results point to an important disruptive potential of introduced dispersers, by altering the selective pressure in favor of species with larger seeds. However, these differences in the size of the dispersed seeds were not reflected in differences in the topological patterns of the interactions, highlighting the need to simultaneously consider biological traits while interpreting interactions networks.
Brawata, Renee Louise. "Is the dingo top dog? : the influence of dingo management on the behaviour of introduced carnivores in arid Australia, with implications for native fauna conservation". Phd thesis, 2012. http://hdl.handle.net/1885/132137.
Texto completoCarne, Vanessa Lynne. "Ecology of Mediterranean snails in Southern Australian agriculture : a study of Cernuella virgata and Cochlicella acuta on the Yorke Peninsula / Vanessa L. Carne". 2003. http://hdl.handle.net/2440/22109.
Texto completoIncludes bibliographical references (leaves 294-333)
2 v. (xxxi, 333 leaves) ; ill. (some col.) ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Thesis (Ph.D.)--University of Adelaide, School of Agriculture and Wine, Discipline of Plant and Pest Science, 2005
Coelho, Ana Isabel Cavaco Pinto. "The dispersal of native and introduced seeds by São Tomé forest birds". Master's thesis, 2016. http://hdl.handle.net/10451/27357.
Texto completoCom a população mundial a aumentar, os impactos antropogénicos nos ecossistemas naturais vão sendo cada vez mais evidentes. Assistimos actualmente a uma elevada taxa de extinção de espécies, e com elas se perdem as funções e os serviços ecossistémicos que prestam, deixando os ecossistemas mais vulneráveis às pressões humanas. Uma dessas funções, essencial à manutenção da dinâmica florestal, é a dispersão de sementes, que nos trópicos é feita essencialmente através de relações mutualistas entre plantas e animais. A eficácia da dispersão pode variar substancialmente em função da espécie dispersora e depende não só da quantidade de sementes que os animais transportam, mas também da qualidade do tratamento que estes proporcionam às sementes. A perda de um dispersor chave num ecossistema pode portanto comprometer a viabilidade das populações de plantas e alterar a dinâmica da vegetação. Os efeitos da perda da biodiversidade são particularmente graves nas ilhas, onde se concentra grande parte das espécies, sobretudo endémicas. Aqui, as espécies evoluíram em isolamento, existindo naturalmente uma menor diversidade de espécies e possivelmente uma menor redundância funcional entre espécies. Estas características fazem com que estes ecossistemas sejam mais frágeis, e é nas ilhas que se tem verificado a maioria das extinções de espécies. Uma das principais ameaças identificadas é a introdução de espécies invasoras, que competem com as espécies nativas, acabando por as excluír. São Tomé é uma pequena ilha oceânica de clima tropical, situada no sistema insular do Golfo da Guiné. Com uma das maiores concentrações de endemismos de todo o mundo, São Tomé está a sofrer as consequências dos impactos humanos, estando a sua biodiversidade bastante ameaçada. Este trabalho tem então como objectivo perceber de que forma as aves estão a contribuir para a dispersão de sementes, uma função ecossistémica essencial para as florestas ricas em endemismos de São Tomé. Para tal, foram definidos três objectivos específicos: (1) avaliar a rede de dispersão de sementes por aves do sub-bosque em floresta de montanha, através da análise dos excrementos de aves capturadas com redes verticais; (2) avaliar a contribuição específica dos pombos como potenciais dispersores de sementes em São Tomé, através da análise de conteúdos de papos de pombos caçados; (3) caracterizar a dispersão de sementes na floresta de montanha, unindo os dados provenientes dos pontos anteriores, ponderados com a abundância relativa das aves. As redes de dispersão de sementes foram construídas analisando as matrizes de interação com o ‘package’ bipartite do programa R. A frequência de interação foi quantificada como o número de excrementos ou papos de cada espécie de ave contendo pelo menos uma semente intacta de cada espécie de planta. Foram capturadas 15 espécies de aves com redes verticais no sub-bosque em floresta de montanha, todas elas endémicas. Confirmámos dispersão de sementes por seis destas espécies, de destacar a contribuição do Olho-grosso (Speirops lugubris), responsável por 88% da frequência de interação. As espécies de plantas nativas dominam esta rede (14 espécies, 70% das espécies identificadas), incluindo algumas espécies endémicas ameaçadas, enquanto que poucas são as espécies introduzidas incorporadas na rede de dispersão (seis espécies, 20% das espécies identificadas). Através de curvas de acumulação de espécies, é possível afirmar que o esforço de captura foi bastante elevado, tendo-se conseguido capturar 71% das espécies de aves que ocorrem na área de estudo e 65% das plantas a serem dispersas. A comparação entre as redes de dispersão de sementes da floresta primária (obô) e da floresta secundária (capoeira) revelou poucas diferenças, o que pode estar relacionado com a proximidade geográfica das áreas de amostragem. Estes resultados sugerem ainda que os dispersores se movem entre os dois tipos de floresta, contribuindo para a disseminação das sementes entre habitats, o que vai facilitar tanto a invasão por espécies introduzidas, como a regeneração de espécies nativas em zonas de floresta degradada. A análise da rede de dispersão de sementes por pombos em São Tomé permitiu verificar a importância das três espécies endémicas caçadas como potenciais dispersores de sementes. Em especial a Rola (Columba malherbii) e o Cécia (Treron sanctithomae), tanto por serem as mais abundantes, como por serem as que mais frequentemente continham sementes no papo. Esta rede é dominada por sementes nativas (53 % da frequência de ocorrência) e apenas uma pequena percentagem de introduzidas (21% da frequência de ocorrência), sendo que uma destas (Cecropia peltata) está incluída na lista das 100 piores espécies invasoras do mundo. Já o Pombo-do-mato (Columba thomensis) é uma espécie mais rara, tendo a sua população vindo a decrescer maioritariamente devido à pressão de caça. É necessária alguma cautela ao analisar estes resultados, uma vez que as sementes nos papos dos pombos teriam ainda de passar por todo o processo de digestão, podendo levar à sua destruição antes de serem depositadas. No entanto, mesmo que poucas sementes resistam à passagem pelo trato digestivo da ave, a probabilidade destas serem dispersas a longa distância é elevada, dada a grande capacidade de voo dos pombos quando comparada com as das restantes aves existentes na ilha. A dispersão de sementes nas florestas de montanha de São Tomé é suportada exclusivamente por aves endémicas, um resultado surpreendente mesmo no contexto de ilhas oceânicas. A grande importância do Olho-grosso como dispersor de sementes resulta não só da frequência com que as dispersa, mas também da sua elevada abundância nestas florestas. Apesar do método utilizado ser dirigido a aves do sub-bosque, foi possível capturar também alguns indivíduos de espécies mais associadas à copa das árvores, como o Neto-de-olho-grosso (Zosterops feae). Foi também possível comprovar que o Pardal (Serinus rufobrunneus) é sobretudo um predador de sementes, já que apenas uma reduzida proporção dos dejectos continha sementes intactas. Os pombos parecem ser quantitativamente pouco relevantes, sobretudo devido à sua abundância reduzida, mas podem constituir importantes dispersores a longa distância e de sementes de maiores dimensões. Foi ainda detetada alguma complementariedade entre os vários dispersores, já que apenas o Tordo (Turdus olivaceofuscus) e o Papafigos (Oriolus crassirostris) foram encontrados a dispersar as sementes maiores (8-10mm). Estes dois dispersores, de maiores dimensões, possuem uma garganta mais larga que lhes permite engolir sementes maiores. A elevada ‘species strength’ destes dispersores reflete isso mesmo: uma grande dependência deles por parte das plantas com sementes maiores, já que estas aves são as únicas capazes de dispersar as suas sementes. O Tchin-tchin-txoló (Ploceus sanctithomae), a Camussela (Ploceus grandis) e o Pastro (Onycognathus fulgidus) já foram observados a consumir frutos e sementes, mas permanecem indicados apenas como potenciais dispersores, pois não foi possível comprovar que desempenhem esta função. Dos nove dispersores de sementes encontrados neste estudo, seis estão ameaçados de extinção, segundo os critérios da IUCN. Este é um facto preocupante, uma vez que a extinção de qualquer um destes dispersores irá ter um impacto negativo na dispersão de sementes, com consequências desconhecidas para a estabilidade do ecossistema. Apesar da importância da dispersão de sementes para a dinâmica florestal, muito pouco se sabe sobre esta função do ecossistema em São Tomé. Este é um trabalho pioneiro nesta área, na medida em que foram dados os primeiros passos para compreender como funciona esta importante função do ecossistema nesta ilha. No entanto ainda há muito por perceber. É preciso uniformizar a metodologia de amostragem e aplicá-la a todos os dispersores e também potenciais dispersores, estendendo a amostragem no espaço e no tempo. É ainda necessário compreender a qualidade do tratamento que cada dispersor dá a cada espécie de planta, inibindo ou aumentando a sua taxa e velocidade de germinação. Para além das aves, focadas neste trabalho, outros grupos de animais terão certamente um papel relevante na dispersão de sementes, nomeadamente os invertebrados, os morcegos frugívoros e alguns dos mamíferos introduzidos, como a Lagaia (Civettictis civetta) e o Macaco (Cercopithecus mona). É também necessário avaliar até que ponto as espécies de plantas introduzidas se comportam como invasoras e de que forma competem com as nativas, diminuindo as suas probabilidades de recrutamento. Finalmente, o transporte das sementes, mesmo que viáveis, não se traduz necessariamente no recrutamento de novos indivíduos: a qualidade do local de deposição é um factor crucial no contributo das aves para a dinâmica populacional dessa planta, e no conjunto, para a dinâmica florestal. Em resumo, esta tese fornece a primeira caracterização da rede de dispersão de sementes de São Tomé, abrindo as portas para um conhecimento mais detalhado e abrangente das interacções biológicas que sustêm as comunidades biológicas nestes ecossistemas.
The island of São Tomé, in the Gulf of Guinea, is a biodiversity hotspot with a remarkable number of endemic species and unique forest ecosystems. Much of its biodiversity is currently threatened by the increasing human population and associated habitat change, which is simultaneously threatening ecosystem functions and services. Seed dispersal is one of such key ecosystem services, essential for forest regeneration. The goal of this work is to understand how forest birds are contributing to the dispersal of both native and introduced seeds in São Tomé, providing the first community-level assessment of species interactions in maintaining ecosystem functions in the island. We collected droppings from mist netted birds and analysed the crop contents of hunted pigeons. All 18 sampled bird species were endemic and nine of them were dispersing seeds. The São Tomé Speirops played a central role as seed disperser. The seed dispersal network is dominated by native plant species, with only a few introduced species being dispersed in the forest. We corrected the frequency of occurrence of seeds in the droppings with independent estimates of bird abundance, and showed that this correction is key to understand disperser contribution to the overall network. Birds are therefore playing a double role, facilitating the dispersal of introduced species but also spreading the native flora. These results highlight a difficult conservation dilemma, since birds might be simultaneously contributing to forest regeneration and to biological invasion.