Дисертації з теми "Biological invasions impact"
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Riley, Leslie Anne. "Estimating invasive species impact interaction strengths, abundance and the role of productivity in a freshwater invasion /." Pullman, Wash. : Washington State University, 2008. http://www.dissertations.wsu.edu/Dissertations/Fall2008/l_riley_111808.pdf.
Повний текст джерелаFournier, Alice. "Modéliser et prédire les invasions biologiques." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS144/document.
Повний текст джерелаBiologicals invasions, the second cause of biodiversity loss worldwide, represent a major threat that our societies have to face. Invasive species correspond to species that, due to human activities, cross geographic and reproduction barriers and expand into new areas in large numbers. This spread into new ecosystems may have severe socio-economic or ecological impacts. The most efficient way to limit these impacts is to predict and avoid biological invasions before they occur by setting up appropriate management plans.The aim of this PhD thesis is to demonstrate that existing predictive models can be further developed and combined together to improve biological invasion predictions. All of the methods developed in this thesis have been applied to social Hymenoptera: ant species (Formicidae) and the Asian hornet (Vespa velutina nigrithorax), but they are generalizable to any other taxa. The questions asked are: can we predict future invader species? Can we improve the spatial predictions of their distribution? Can we predict invasive species impact?First, I show in this thesis that it is possible to develop a model that detects future invasive species, even before they have had the chance to be moved outside their native range. I apply this screening tool to more than 2000 ant species, provide a list of the 15 ant species that are highly likely to become invasive and map their global suitability to highlights the area the most at risk from these invasions. All continents are threatened by at least one of these potential invasions. Second, I set up a methodological framework to improve species distribution predictions by combining multi-scale drivers. I apply this method to the invasive Asian hornet, identify its high affinity habitats, and use this information to refine suitability maps. I show that integrating multiple drivers, while still respecting their scale of effect, produced a potential range 55.9% smaller than that predicted using a climatic model alone. Finally, I propose a method to predict invasive species impacts in a spatially explicit way and I apply it to the estimate the Asian hornet’s impact on honeybee colonies in France. To do so, I estimate the Asian hornet nest density across France and combine it with an agent-based hive model to estimate honeybee mortality risk. I show that up to 41% of the honeybee colonies are likely to collapse due to the Asian hornet.Overall, these studies demonstrate how modelling techniques can provide valuable inputs to improve invasive species management decision by offering tools to optimize prevention strategies and target areas, species or habitats where action is needed in priority. Biological invasions involve our scientific, political and cultural perceptions in an intricate way; this PhD thesis highlights the usefulness of bringing together modelling techniques and the rest of biological invasion knowledge to better grasp invasion science complexity
Dudei, Nicole L. "The impact of the Richmondian Invasion on paleobiogeographic distribution of taxa in the Late Ordovician C₄ sequence (Richmondian Stage, Cincinnati, Ohio) including a comparison of range reconstruction methods." Ohio : Ohio University, 2009. http://www.ohiolink.edu/etd/view.cgi?ohiou1245437297.
Повний текст джерелаCarol, Bruguera Joaquim. "Ecology of an invasive fish (Silurus glanis) in Catalan reservoirs." Doctoral thesis, Universitat de Girona, 2007. http://hdl.handle.net/10803/7870.
Повний текст джерелаThe aim of this thesis is to provide the first data on the ecology of European Catfish (Silurus glanis) introduced to the Iberian Peninsula and to appraise its ecological impact on native biota. We sampled the fish assemblage of 14 Catalan reservoirs (Spain). The European catfish is nowadays introduced in four Iberian river basins: in the Ebro river basin for 30 years, in the Ter and Tajo river basin for a few years and we report the first record for the Llobregat river basin. We demonstrate the utility of comparing early and late invasion stages to understand the ecological changes caused by invasive species: recent introductions of catfish had smaller and younger catfish with growth rates higher than old and native populations and preying on fish instead of crayfish for old introductions. We also report the first published telemetry data for catfish.
Miró, Pastó Alexandre. "Fish as local stressors of Pyrenean high mountain lakes: Arrival process and impact on amphibians and other organisms." Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/384835.
Повний текст джерелаLuruli, Ndivhuwo Mord. "Distribution and impact of the Argentine ant, Linepithema humile (Mayr), in South Africa." Thesis, Stellenbosch : Stellenbosch University, 2007. http://hdl.handle.net/10019.1/19640.
Повний текст джерелаENGLISH ABSTRACT: Invasion by the notorious tramp species, the Argentine ant (Linepithema humile Mayr) (Hymenoptera: Formicidae) has caused major concern around the globe, owing to its displacement of native ant species and other invertebrates where it invades. This species was first recorded in South Africa in 1901 in Stellenbosch, Western Cape Province (WCP), and has now become a significant pest in most urban and agricultural areas in the country. The Argentine ant has received relatively little attention in South Africa compared to other countries (e.g. California, North America). To date the extent of invasion by this species countrywide, as well as its impact on the local ant fauna inside protected areas, has not been quantified. In this study, the impact of the Argentine ant on native ant fauna inside three protected areas in the WCP (Helderberg Nature Reserve (HNR), Jonkershoek Nature Reserve (JNR) and Kogelberg Biosphere Reserve KBR)) was assessed. Species richness and diversity were compared between invaded and uninvaded bait stations at each protected area. Several native ant species were found to be displaced by the Argentine ant from all three protected areas, although three species: Meranoplus peringueyi, Monomorium sp. 8 and Tetramorium quadrispinosum, were found coexisting with it. Invaded bait stations had significantly lower ant species richness and species turnover than uninvaded bait stations. Uninvaded bait stations contained eight times more native ant species than invaded bait stations. Thus, the invasion of protected areas by the Argentine ant has severe negative consequences for the species richness and assemblage structure of native ants, leading to the biotic homogenization of these local ant communities. The distribution range of the Argentine ant inside the three protected areas (HNR, JNR, KBR), as well as microhabitat preferences that may facilitate the spread of this species inside these reserves, was also assessed. Helderberg Nature Reserve was the most invaded protected area, with the highest level of the Argentine ant occupancy, while JNR and KBR had lower occupancy levels. At all the three protected areas, this species was dominant at lower altitudinal areas, and also showed a clear preference for areas with high anthropogenic disturbances, i.e. around buildings and on lawns (picnic areas). In this study, there was no evidence that moisture availability facilitates the distribution and spread of the Argentine ant inside these reserves. Finally, a combination of published literature records, museum records and records collected in the current study was used to quantify the current distributional extent of the Argentine ant throughout urban South Africa. This is the first study quantifying the distribution and extent of invasion by the Argentine ant throughout the country. The Argentine ant was found in six of the nine South African Provinces, and its extent of occurrence includes approximately half of the country’s land surface area. Discontinuities in the distribution of the Argentine ant across the country revealed that range expansion of the Argentine ant in South Africa is occurring predominantly via human-mediated jump dispersal, rather than naturally via nest diffusion. This study clearly demonstrated that the Argentine ant is well established across South Africa as well as inside protected areas. The Argentine ant invasion was influenced by the presence of human modified landscapes (i.e. buildings) both at low and high altitude, and this was associated with higher rates of native ant species displacement at these areas. Therefore, limiting the development of recreational areas, such as buildings and picnic sites inside protected areas will result in the lower rate of spread of the Argentine ant. This will in turn lower the extent of displacement of native ant species.
AFRIKAANSE OPSOMMING: Indringing deur die Argentynse mier (Linepithema humile Mayr) (Hymenoptera: Formicidae) is ‘n bron van groot kommer regoor die wêreld, as gevolg van sy vermoë om inheemse mier spesies en ander ongewerweldes te verplaas. Hierdie spesie is vir die eerste keer aangeteken in Suid-Afrika in 1901, in Stellenbosch, Weskaap Provinsie (WCP), en het ‘n belangrike pes geword in die meeste stedelike en landelike gebiede in die land. Die Argentynse mier het betreklik min aandag gekry in Suid-Afrika, in vergelyking met ander lande (bv. California, Noord Amerika). Tans is die omvang van die landwye indringing van hierdie spesie, sowel as sy impak op die plaaslike mier fauna binne beskermde areas, nog nie bepaal nie. In hierdie studie word die impak van die Argentynse mier op die inheemse mier fauna binne drie beskermde areas in die WCP (Helderberg Natuurreservaat (HNR), Jonkershoek Natuurreservaat (JNR) en Kogelberg Biosfeerreservaat (KBR)) bepaal. Spesierykheid en diversiteit was vergelyk tussen ingedringde en oningedringde lokaas stasies in elke beskermde area. Verskeie inheemse mier spesies was deur die Argentynse mier verplaas in al drie beskermde areas, alhoewel drie spesies: Meranoplus peringueyi, Monomorium sp. 8 en Tetramorium quadrispinosum het saam met dit voorgekom. Ingedringde lokaas stasies het beduidend laer mier spesierykheid en spesies omset gehad as oningedringde lokaas stasies. Dus, die indringing van beskermde areas deur die Argentynse mier het ernstige negatiewe gevolge vir die spesierykheid en gemeenskap struktuur van inheemse miere, wat lei tot die biotiese verarming van hierdie plaaslike mier gemeenskappe. Die verspreidingsarea van die Argentynse mier binne die drie beskermde areas (HNR, JNR, KBR), en die mikrohabitat voorkeure wat die verspreiding van die spesie binne hierdie reservate kan vergemaklik, was ook vasgestel. Helderberg Natuurreservaat was die mees ingedringde beskermde area, met die hoogste vlak van Argentynse mier besetting, terwyl JNR en KBR laer besettingsvlakke gehad het. By al drie die beskermde areas was hierdie spesie dominant by laer hoogtes bo seevlak en het ‘n duidelike voorkeur getoon vir areas met hoë menslike versteuring d.i. rondom geboue en op grasperke (piekniek areas). In hierdie studie was daar geen bewyse dat vog beskikbaarheid die voorkoms en verspreiding van die Argentynse mier binne die reservate vergemaklik nie. Ten slotte, ‘n kombinasie van gepubliseerde literatuur verslae, museum dokumente en verslae wat in hierdie studie versamel is, was gebruik om die huidige verspreidingsomvang van die Argentynse mier te bepaal. Dit is die eerste studie wat die verspreiding en omvang van indringing in stedelike Suid Afrika van die Argentynse mier dwarsdeur die land bepaal. Die Argentynse mier is gevind in ses van die nege provinsies in Suid-Afrika, en die omvang van sy voorkoms sluit bykans die helfte van die land se landoppervlaksarea in. Onderbrekings in die verspreiding van die Argentynse mier deur die land het blootgelê dat die uitbreiding van die voorkomsgebied van die Argentynse mier in Suid-Afrika hoofsaaklik gebeur deur mens bemiddelde verspreiding eerder as natuurlike nesverspreiding. Hierdie studie het duidelik gedemonstreer dat die Argentynse mier goed gevestig is regoor Suid-Afrika sowel as in beskermde areas. Die Argentynse mier indringing was beïnvloed deur mensgewysigde landskappe (d.i. geboue) by lae en hoë hoogtes bo seevlak, en dit was verwant aan hoër vlakke van verplasing van inheemse mier species in hierdie areas. Dus, die beperking van ontwikkeling van rekreasie areas, soos geboue en piekniekareas, in beskermde gebiede sal lei tot laer vlakke van verspreiding van die Argentynse mier. Dit sal, op sy beurt, die omvang van verplasing van die inheemse mier spesies verminder.
Ellis, Bonnie Kathleen. "Alternate states in a large oligotrophic lake a retrospective analysis of nutrient loading and food web change /." [Missoula, Mont.] : The University of Montana, 2008. http://etd.lib.umt.edu/theses/available/etd-03292007-094249/unrestricted/ellis06.pdf.
Повний текст джерелаGaigher, Rene. "The invasive ant Pheidole megacephala on an oceanic island : impact, control and community-level response to management." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/79877.
Повний текст джерелаENGLISH ABSTRACT: Invasive species are among the most important global conservation threats. Their management is one of the key conservation challenges that will have to be addressed in the next few decades. The study of real invasions and their management in natural ecosystems provides an opportunity to gain important information on theoretical and applied aspects of biological invasions. This project focuses on the broader ecological context of invasive ant management in an ecologically sensitive island habitat. The thesis has three main components: 1) assessing the role of the invasive ant Pheidole megacephala in the ecosystem and evaluating its threat to the system, 2) evaluating a low-impact management program for the ant, and 3) using a community-level approach to assess ecosystem response to ant removal. The ant occupied almost 30% of the island‘s total land area and reached extremely high densities in some areas. The ant was associated with exotic hemipteran scale insects through trophobiotic mutualisms that facilitated high ant and hemipteran abundances. The highly destructive scale insect Pulvinaria urbicola was among the hemipterans that benefited from ant attendance. High levels of hemipteran feeding resulted in dieback of functionally important and threatened native Pisonia trees, which represented a significant threat to the forest ecosystem. A management program was initiated in response to this threat, consisting of baiting with selective hydramethylnon-based bait delivered in bait stations, accompanied by detailed pre-and post-baiting monitoring. The method was highly effective at suppressing the ants, whilst preventing bait uptake by non-target organisms. It was also cost-effective and adaptable to ant density in the field, but was only effective over short distances. The method may be applicable to other sensitive environments with similar challenges. After ant control, the ant-scale mutualism was decoupled and the Pu. urbicola population collapsed. There were variable responses in different taxa to the removal of these highly abundant exotic species, the most important of which was the recovery in Pisonia trees. Shoot condition and foliage density improved and there was a decrease in sooty mold. Herbivory on Pisonia increased due to recovery of native canopy herbivores, but the overall impact was far less than that of the exotic hemipterans. Soil surface arthropods, a group that may have been vulnerable to the treatment method, were unaffected by baiting. Instead, they increased significantly after ant removal, confirming the ant‘s impact on other arthropods. Other ant diversity and non-ant arthropod abundance increased post-baiting, including the endemic ant Pheidole flavens farquharensis and some functionally important insects such as the Indian cockroach. Natural enemies that interacted predictably with the mutualists were influenced by management. Predators of hemipterans increased significantly after ant removal and were instrumental in the scale population collapse, whereas parasitoids of hemipterans that benefited from the mutualism declined. Additionally, groups that were unrelated to the mutualism were indirectly influenced by management. The natural enemy assemblage as a whole showed recovery to pre-invasion conditions. The study shows how widely interconnected and influential the ant was in the ecosystem. It highlights the threat of the species in natural systems as well as the complex responses following invasive ant removal. Yet, it also demonstrates the potential to safely and effectively manage the species, thereby raising the opportunity for ecosystem recovery.
AFRIKAANSE OPSOMMING: Indringerspesies is van die belangrikste globale bedreigings vir natuurbewaring. Hulle bestuur is van die grootste bewaringsuitdagings wat in die volgende paar dekades aangespreek moet word. Die studie van werklike invalle en hul bestuur in natuurlike ekosisteme bied 'n geleentheid om belangrike inligting te verkry oor teoretiese en toegepaste aspekte van biologiese indringing. Hierdie projek fokus op die breër ekologiese konteks van uitheemse mier bestuur in 'n ekologies sensitiewe eiland habitat. Die tesis het drie hoofkomponente: 1) die beoordeling van die rol van die indringer mier Pheidole megacephala in die ekosisteem en evaluering van sy bedreiging vir die sisteem, 2) die evaluering van 'n lae-impak bestuursprogram vir die mier, en 3) die gebruik van 'n gemeenskaps-vlak benadering om ekosisteem reaksie op mierverwydering te assesseer. Die mier het byna 30% van die totale landoppervlak van die eiland beslaan en het in party areas baie hoë digthede bereik. Die mier was geassosieer met uitheemse dopluis spesies in mutualismes wat hoë mier en dopluis getalle gefasiliteer het. Die hoogs beskadigende dopluis Pulvinaria urbicola was een van die spesies wat bevoordeel is deur die mutualisme. Hoë vlakke van dopluis voeding het die terugsterwe van funksioneel belangrike, bedreidge inheemse Pisonia bome veroorsaak, wat ʼn groot bedreiging vir die ekosisteem verteenwoordig het. ‗n Bestuursprogram is geïmplimenteer as gevolg van hierdie bedreiging, wat bestaan het uit selektiewe hidrametielnoon-gebaseerde lokaas wat in die veld geplaas is in lokaashouers, vergesel deur intensiewe monitering voor en na lokaasplasing. Die metode was hoogs effektief in die onderdrukking van die miere en het lokaasinname deur nie-teiken organismes verhoed. Dit was ook koste-effektief en aanpasbaar volgens mierdigtheid in die veld, maar was slegs effektief oor kort afstande. Die metode mag van toepassing wees in ander sensitiewe omgewings met soortgelyke uitdagings. Na mierbeheer is die mier-dopluis mutualisme ontkoppel en die Pu. urbicola bevolking het drasties verminder. Daar was verskillende reaksies in verskillende taxa tot die verwydering van die oorvloedryke eksotiese spesies, maar die belangrikste reaksie was die herstel van Pisonia bome. Spruittoestand en blaardigtheid het verbeter en daar was ʼn afname in roetskimmel. Herbivorie op Pisonia het toegeneem as gevolg van ʼn herstel in inheemse herbivore, maar die algehele impak was veel minder as dié van die eksotiese dopluis. Grondoppervlak gelidpotiges, 'n groep wat kwesbaar kon wees vir die behandelingsmetode, was onaangeraak deur die lokaas, maar het beduidend na mierverwydering vermeerder. Mierdiversiteit het vermeerder en die Seychelles endemiese mier Pheidole flavens farquharensis is hervestig. Ander gelidpotiges het ook vermeerder, insluitend funksioneel belangrike spesies soos die Indiese kakkerlak. Natuurlike vyande wat geassosieer was met die mutualiste is beïnvloed deur die mierbestuur. Predatore van dopluis het beduidend toegeneem na mierverwydering en was hoogs betrokke by die vermindering van dopluis, terwyl parasiete van dopluis, wat voordeel getrek het uit die mutualisme, gedaal het. Daarbenewens is groepe wat onverwant was aan die mutualisme indirek beïnvloed deur mierbestuur. Die algehele natuurlike vyand gemeenskap het herstel na pre-indringing toestand. Die studie toon hoe wydverbind en invloedryk die mier was in die ekosisteem. Dit beklemtoon die bedreiging van die spesies in natuurlike stelsels asook die komplekse reaksies wat uitheemse mierverwydering volg. Tog demonstreer dit die potensiaal om die spesies veilig en doeltreffend te bestuur, en sodoende die geleentheid vir ekosisteemherstel te skep.
Meffin, Ross. "Invasion success and impacts of Hieracium lepidulum in a New Zealand tussock grassland and montane forest." Lincoln University, 2010. http://hdl.handle.net/10182/1808.
Повний текст джерелаLe, Yannou-Cateine Maureen. "La myrmécochorie en nouvelle-Calédonie : importance du contexte et impact des fourmis introduites sur ce service." Thesis, Nouvelle Calédonie, 2017. http://www.theses.fr/2017NCAL0007/document.
Повний текст джерелаThe biosphere is experiencing a biodiversity crisis, which for islands are the epicenter. Biological invasions are there, one of the main drivers, especially regarding the alteration of mutualistic relationships for the functioning and the maintenance of ecosystems. Thus, during our work in New Caledonia, we focused on a key group for ecosystem functions: ants, and their involvement in seed dispersal (myrmecochory). We carried out the first assessment of this mutualism in New Caledonia with the identification of indigenous myrmechorous plants, with a preponderance of species on ultramafic soils. Then, we evaluated the magnitude of seed dispersal by ants on these soils. After the characterisation of ant communities across an anthropic disturbance gradient, we evaluated seed dispersal capabilities of exotic ant compared to native ones. Solenopsis geminata appears to offer a more efficient seed dispersal than natives. On the other hand, Wasmannia auropunctata excludes native species without ensuring effective dispersal. In the context of an intense disturbance regime, our work illustrates a neo-assembled community of ants, dominated by exotic ones, some of which could provide a function relay with respect to maintaining the dynamic of maquis. Our work illustrates the “context dependency” of invasive species’ impacts as a function of anthropogenic disturbance’s level. It also discusses the possible contribution of these ants in a context of restoration after disturbance of habitats on ultramafic substrates, or even their use in ecological engineering program
Schoeman, Colin Stefan. "Synergistic impact of invasive alien plants and the alien Argentine ant on local ant assemblages in the Western Cape." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/21759.
Повний текст джерелаENGLISH ABSTRACT: Alien trees, Pinus spp. and Eucalyptus spp., affect ants negatively in the Cape Floristic Region (CFR), a global biodiversity hotspot in South Africa. They reduce ant abundance and species richness, thus also changing ant assemblage structure. This is alarming, because almost 1300 species of plant species in the CFR are dispersed by certain indigenous ants, and thus there is concern for an indirect effect on indigenous plant assemblages. One of the most impacting ant species on seed dispersal is the invasive Argentine ant (Linepithema humile (Mayr)), which discards seeds outside its nest, where they do not germinate. Ten sites, on Vergelegen Wine Estate, were selected to explore these effects of alien plants. These varied from invaded to non-invaded sites. Each site consisted of six sampling points, which in turn consisted of four pitfall traps left out for seven days, during December 2005, February 2006, May 2006 and September 2006. Forty species of ant were sampled, and various analyses used to illustrate the comparative effects of plant invasion. All analytical methods showed that invasive alien plants had a significant impact on the abundance and richness of the ant species assemblage, by creating a dense canopy cover that changed the abiotic environment of the epigaeic ants’ habitat. Furthermore, increased alien tree invasion correlated significantly with Argentine ant abundances. The Argentine ant displaced Pheidole capensis and Camponotus spp., while it decreased the abundances of commonly-occurring indigenous ants, such as Lepisiota capensis and Plagiolepis spp. Displacement by the Argentine ant may be a result of indirect competition for food resources. The effects of invasive aliens are synergistic in that there is a cascade effects from initial plant invasions to subsequent animal invasion.
AFRIKAANSE OPSOMMING: Indringer bome, Pinus en Eucalyptus, affekteer miere op negatiewe wyse in die Kaap Florsitiese Streek (KFR), ‘n area in Suid Afrika van belang t.o.v. globale biodiversiteit. Hierdie uitheemse indringer bome verminder hulle hoeveelheid en spesies rykheid. Die bogenoemde is kommerwekkend omdat meer as 1300 plant spesies in the KFR versprei word deur miere. Die verandering in hoeveelheid en versameling van inheemse miere kan dus ernstige implikasies hê op die saad verspreiding van inheemse plant spesies. Een van die mees verwoestende effekte op saad verspreiding is veroorsaak deur die indringer Argentynse mier (Linepithema humile (Mayr)), wat sade neer werp buite hulle neste, waar hulle nie suksesvol kan ontkiem nie. Tien monsterings-tereine was geselekteer om die bogenoemde effekte te ondersoek op Vergelegen Landgoed. Hierdie het afgewissel van indringer tot skoon tereine. Elke terrein is op ses versamelings-plekke gemonster, met vier pitvalle, wat oopgelê het vir sewe dae gedurende Desember 2005, Februarie 2006, Mei 2006 en September 2006. 40 spesies van miere was gemonster. Indringer plante het ‚n betekenisvolle impak gehad het op die hoeveelheid en rykheid van die mier gemeenskappe, deur die skepping van ‚n dig baldakyn wat die abiotiese omgewing van die miere se habitat verander het. Die vermeerdering van indringer plante veroorsaak die vermeerdering van Argentyne miere. Kanonieke Mede-Respons Analise illustreer dat die Argentynse mier Pheidole capensis en Camponotus spp. verplaas het, terwyl dit ander inheemse mier getalle verminder het, soos Lepisiota capensis en Plagiolepis spp. Die verplasing deur die Argentynse mier mag die resultaat wees van indirekte wedywering vir hulpbronne. Die effekte van indringer species is dus sinergisties deur dat ‚n kaskade effek ontstaan vanaf plant tot dier indringer spesies.
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.
Повний текст джерелаJaeger, Andrea L. "Invasive species impacts on ecosystem structure and function." Diss., Connect to online resource - MSU authorized users, 2006.
Знайти повний текст джерелаKadye, Wilbert Takawira. "Assessing the impacts of invasive non-native African sharptooth catfish Clarias Gariepinus." Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1005070.
Повний текст джерелаMcClees, Whitney Elizabeth. "Anthropogenic Effects on the Fouling Community: Impacts of Biological Invasions and Anthropogenic Structures on Community Structure." PDXScholar, 2017. https://pdxscholar.library.pdx.edu/open_access_etds/3883.
Повний текст джерелаCordonnier, Marion. "Impacts of global changes on biological invasions and interspecific hybridization within the Tetramorium caespitum ant species complex." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1243/document.
Повний текст джерелаClimate change, urbanization, biological invasions and interspecific hybridization are major current threats to biodiversity. The objective of this thesis was to assess their interactive effects in Tetramorium ant species from the Rhône-Saône valley in France. Using a broad array of tools from several fields of biology, I worked on almost two thousand colonies from five Tetramorium species including T. immigrans and T. caespitum. Both climate and urbanization limited the ranges of these species, and urbanization impacted their distributions simultaneously at several spatial scales. The occurrence probabilities of T. immigrans depended on the interaction between climatic and urban factors. Several introductions from external sources seemed to have given rise to four genetically distinct populations of T. immigrans, making it likely that it is not native to the northernmost urban areas. Hybridization and introgression between T. immigrans and T. caespitum was frequent in zones of sympatry, and the detection of nuclear DNA backcrosses and mitochondrial-nuclear DNA discordance between the two species suggested that hybridization lead to fertile offspring (i.e. introgression). Cuticular hydrocarbon profiles were clearly differentiated between the two species and were correlated to heightened interspecific aggression against heterospecifics. Both species presented a monogyne polyandrous mating system, in which hybrid queens but no hybrid fathers contributed to hybrid offspring. Few studies on interspecific hybridization have addressed global change or biological invasions. These concepts are infrequently studied together, and their interactive effects are overlooked in the current literature. Taking these interrelationships into account and exploring multiple scales are essential to better understand the processes that generate patterns of genetic exchange
Miniutti, Danielle. "Assessing Impacts of the Aquatic Invaders in Maine (AIM) Workshop on Inquiry Pedagogy and Student Learning." Fogler Library, University of Maine, 2009. http://www.library.umaine.edu/theses/pdf/MiniuttiD2009.pdf.
Повний текст джерелаKrapfl, Kurt J. "IMPACTS OF HEMLOCK WOOLLY ADELGID ON TSUGA CANADENSIS FOREST COMMUNITIES IN GREAT SMOKY MOUNTAINS NATIONAL PARK, USA." OpenSIUC, 2010. https://opensiuc.lib.siu.edu/theses/175.
Повний текст джерелаPoulette, Megan Marie. "ECOSYSTEM IMPACTS OF THE INVASIVE SHRUB LONICERA MAACKII ARE INFLUENCED BY ASSOCIATIONS WITH NATIVE TREE SPECIES." UKnowledge, 2012. http://uknowledge.uky.edu/biology_etds/6.
Повний текст джерелаSurget, Gwladys. "Processus adaptatifs des végétaux marins face au changement climatique à différentes échelles de temps et d'espace : dynamique de populations, métabolomique, écophysiologie et potentiels de valorisation." Thesis, Brest, 2017. http://www.theses.fr/2017BRES0056/document.
Повний текст джерелаThree model species with a large distribution along European coasts, along a latitudinal gradient from Norway to Portugal was chosen: Sargassum muticum, Codium fragile and Gracilaria vermiculophylla. The aims of this PhD thesis were to study the phenology, ecophysiology and the metabolom of these non-native marine macrophytes and their ability to cope with a variation of environmental factors 1) at a population scale, 2) along the latitudinal gradient (in relation with the global climatic change) and to propose 3) bio-inspired molecules for industrial purposes. The latitudinal gradient corresponding to a thermic gradient, allows to imitate the global warming as climatic change ¡mpacts are most of the time only visible at decennial scale.Monitorings of ecology, metabolome and potential impacts of these macroalgae, at a population scale, allowed to study the development and life cycle of these models. In particular, G. vermiculophylla exhibited a specific phenology (with a majority of small vegetative fragments, <3cm) in the Bay of Brest and a highly tolerance to burial until 12 cm depth in the sediment by acclimatizing its metabolome together with the ability to maintain a dormancy physiology. This engineer species modifies deeply muddy shores of this Bay. Latitunal gradients's monitoring highlighted the phenological plasticity and a contrasted invasive potential of C.fragile between latitudes. During low spring tides, species exhibited an acclimation of their photophysiology between latitudes with photoinhibition process related to induce environmental stress. Furthermore, this work showed the multifunctional properties of polyphenols enriched extracts with antioxidant, photoprotective or osteogenic activities, highlighting the emergence of original bio-inspired pathways for cosmetic or biomaterial applications
Enríquez, Lenis Martha Lucía. "The invasion of the Argentine ant Linepithema humile in Mediterranean ecosystems: impacts and efficacy of winter aggregations extirpation as a control methods." Doctoral thesis, Universitat de Girona, 2012. http://hdl.handle.net/10803/101512.
Повний текст джерелаEs van comparar les característiques i els efectes de la invasió de la formiga argentina sobre la comunitat de formigues natives, i altres artròpodes. Es va avaluar l'efecte de l'extirpació d’agregacions de nius d’hivern, la selecció de llocs de nidificació i l'ús de nius artificials com a eina de control, i es va mesurar la seva taxa d'expansió. Es va trobar que la invasió provoca canvis importants en la comunitat de formigues natives. La temperatura ambiental influeix en l'expansió, i les pertorbacions de l'hàbitat podrien afavorir una propagació més ràpida. L'extirpació disminueix la seva abundància i pertorba la seva dinàmica poblacional. L'extirpació s'ha de fer al marge de la invasió, i s'ha de centrar en nius situats sota les pedres més grans que és on hi ha més probabilitat de trobar nius madurs. Finalment, aquest mètode es proposa principalment per al control de la invasió en àrees tancades o aïllades.
Franke, Morgan Elizabeth. "Understanding Invasive Species Impacts on Reclaimed Surface-Mined Lands." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/73660.
Повний текст джерелаMaster of Science in Life Sciences
Rocha, Kortz Alessandra. "Biodiversity change in the Cerrado following invasive pine tree establishment." Thesis, University of St Andrews, 2017. http://hdl.handle.net/10023/12220.
Повний текст джерелаFilho, Walter Mesquita. "Invasão e estabelecimento de Digitonthopagus gazella (Coleoptera, Scarabaeidae) em Selvíria, MS e seus impactos na comunidade de besouros coprófagos nativos durante 22 anos." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/11/11146/tde-04012018-151155/.
Повний текст джерелаBiological invasions are one of the major threats to the global biodiversity. The use of exotic species as agents of biological control is one way to contribute to invasions. In some cases, the introduced species became invasive. The tunneler dung beetle (DB) Digothophagus gazella is a good example. Released in many countries, including Brazil, to improve dung pad removal, the species quickly spread to new ones, where it is considered as an invasive species. The objective of this thesis was to evaluate impacts of D. gazella on the abundance, alfa-diversity and turnover of a native DB community in Brazil. Another exotic DB species, the dweller Labarrus pseudolividus, was present in the study area. The community was sampled weekly, at the same location, from November 1989 until November 2015 using a black light trap. The exotic species was first recorded four years after the beginning of sampling. The invasion by D. gazella changed significantly the native community. Abundance, diversity and richness were increasing during the first years, however they all decreased since the invasion. Species with the same nesting behavior of D. gazella (tunneler) were not able to recover from the impacts, with turnover, abundance and species richness continuously decreasing after the invasion. Dweller species on the contrary were able to partially recovery after some years, rebound its abundance and turnover since year 15. Results from the turnover analysis of the current community, which is native and exotic, showed that it has been influenced by both exotic species. Following the decrease in abundance of D. gazella and native species, L. pseudolividus was able to increase its abundance, leading to stabilization of the turnover despite the opposite observed in the native community. Since the invasion by D. gazella, weather variables became less important on the changes observed.
Gidoin, Cindy. "Impacts écologiques de l’invasion d’un insecte prédateur de graines (Hymenoptera Torymidae) dans un écosystème forestier méditerranéen." Thesis, Montpellier, SupAgro, 2014. http://www.theses.fr/2014NSAM0015/document.
Повний текст джерелаBiological invasions produce novel species assemblages in communities that likely result in novel interspecific interactions. Ecological impacts of invasions may be: (i) indirect, if the invader enters competition with resident species, and (ii) indirect if the invader is a predator or a parasite of resident species. Both indirect and direct ecological invasion impacts are likely to apply to invasive wasps of the Megastigmus genus (Hymenoptera: Torymidae), which exploit narrow ecological niches that overlap with those of resident insect species, and contribute to high mortality levels in host plant populations due to their high specialization on seeds. This thesis aimed at testing such predictions by studying the impacts of the invasion of M. schimitscheki on: (i) its resident competitor for the seed resource M. pinsapinis, and (ii) the expanding populations of its obligatory host the Atlas cedar (Cedrus atlantica) in southeastern France.An extensive spatio-temporal survey of Megastigmus spp. populations indicated that the rapid expansion of M. schimitscheki was associated with a strong decline of M. pinsapinis. A mechanistic-statistical modelling approach allowed us to show that an earlier phenology of M. schimitscheki had a stronger explanatory power of both invasion success and the competitive exclusion of the resident than temporal variation in resource supply.A theoretical approach of the indirect impact of M. schimitscheki on C. atlantica expansion dynamics was based on reaction-diffusion models. We showed that an Allee effect resulting from seed predation at the expansion front of a host population may increase the genetic contribution of host individuals situated in the bulk of the expansion front. Interestingly, this phenomenon results in a limited erosion of genetic diversity during the expansion phase of the host population.The empirical and theoretical approaches developed showed that the invasion of M. schimitscheki in French cedar forests had a strong and negative indirect impact on the demography of a resident species, but, parallely, such invasion may directly favour the maintenance of genetic diversity in expanding host plant populations
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.
Повний текст джерелаFeral 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
Korsu, K. (Kai). "Ecology and impacts of nonnative salmonids with special reference to brook trout (Salvelinus fontinalis Mitchill) in North Europe." Doctoral thesis, University of Oulu, 2008. http://urn.fi/urn:isbn:9789514288647.
Повний текст джерелаDaga, Vanessa Salete. "Variações espaciais e temporais na abundância das espécies introduzidas em um hotspot de biodiversidade global, rio Iguaçu, Paraná, Brasil: impactos sobre a ictiofauna nativa." Universidade Estadual do Oeste do Parana, 2010. http://tede.unioeste.br:8080/tede/handle/tede/1955.
Повний текст джерелаThe objective of this study was to evaluate the composition and structure of the assemblages of native and nonnative fish along the temporal and spatial gradient on the Iguaçu River, and their relations with environmental variables in five reservoirs. Samples were collected from January 2004 to December 2008, with periodicity quarterly in reservoirs Foz do Areia, Segredo and Salto Caxias, while in reservoirs Salto Santiago and Salto Osório samples were bimonthly. Catches were made with the aid of gillnets (mesh size of 2.4 to 16 cm) and trammel nets (witches, 6, 7 and 8 cm between non-adjacent), operated on the surface, margin and bottom, exposed for 24 hours with checked at 8:00, 16:00 and 22:00 hours. Fish caught were identified, measured and weighed. The community structure was evaluated by its attributes of species (richness), abundance (biomass and number of individuals) and diversity index of Shannon. The environmental variables were plotted on a matrix (physics and chemistry) and is summarized by principal component analysis (PCA). To summarize the data on the composition and structure of the assemblages of native and nonnative fish, analysis of non-metric multidimensional scaling (NMDS) was used. The degree of association between multivariate matrices (environmental variables and the composition and structure of the assemblages of native fish and non-native) was assessed by means of a Procrustes routine. During the study period were collected from 152,007 specimens, 148,084 individuals of native species and 3,923 specimens of non-native species, which were divided into six orders, 16 families, 32 genera and 50 species. The most abundant native species were Astyanax sp. B (40.1%), Astyanax sp. C (19.1%) and Pimelodus britskii (9.1%). The non-native species were more abundant Odontesthes bonariensis (85.1%), Prochilodus lineatus (7.5%) and Tilapia rendalli (4.9%). The distribution of abundance in numbers and weight was higher in Salto Santiago, both native and non native. Spatial and temporal differences were apparent for wealth, for both native and non native, but the Shannon diversity index showed significant differences only for native species. The composition and structure of the assembly of native and nonnative fish showed significant differences along the longitudinal gradient of the Iguaçu River. The physical and chemical variables (water temperature, water transparency, pH and electrical conductivity) were significant for the separation of the reservoirs along the longitudinal gradient. Procrustes analysis showed that an association exists between the physical and chemical variables, and the spatial arrangement of the composition and structure of the assemblages of native fish.
O objetivo deste trabalho foi avaliar a composição e estrutura da assembleia de peixes nativos e não nativos, ao longo do gradiente espacial e temporal no rio Iguaçu e, suas relações com as variáveis ambientais em cinco reservatórios. As amostragens foram realizadas de janeiro de 2004 à dezembro de 2008, com periodicidade trimestral nos reservatórios de Foz do Areia, Segredo e Salto Caxias, enquanto que nos reservatórios de Salto Santiago e Salto Osório as amostragens foram bimestrais. As capturas foram realizadas com o auxílio de redes de espera simples (malhas de 2,4 a 16 cm) e tresmalhos (feiticeiras de 6, 7 e 8 cm entre nós não adjacentes), operadas na superfície, margem e fundo, expostas por 24 horas com revistas às 8:00, 16:00 e 22:00 horas. Os peixes capturados foram identificados, medidos e pesados. A estrutura da comunidade foi avaliada pelos seus atributos número de espécies (riqueza), abundância (biomassa e número de indivíduos) e índice de diversidade de Shannon. As variáveis ambientais foram plotadas em uma matriz (física e química), sendo essa sumarizada pela análise de componentes principais (PCA). Para sumarizar os dados de composição e estrutura da assembleia de peixes nativos e não nativos, a análise de escalonamento multidimensional não-métrico (NMDS) foi utilizada. O grau de associação entre as matrizes multivariadas (variáveis ambientais e composição e estrutura da assembleia de peixes nativos e não nativos) foi avaliado por meio de uma rotina Procrustes. Durante o período amostral foram coletados 152.007 exemplares, sendo 148.084 indivíduos de espécies nativas e 3.923 exemplares de espécies não nativas, que foram distribuídos em seis ordens, 16 famílias, 32 gêneros e 50 espécies. As espécies nativas mais abundantes foram Astyanax sp. B (40,1%), Astyanax sp. C (19,1%) e Pimelodus britskii (9,1%). As espécies não nativas mais abundantes foram Odontesthes bonariensis (85,1%), Prochilodus lineatus (7,5%) e Tilapia rendalli (4,9%). A distribuição de abundância, em número de indivíduos e peso foi maior em Salto Santiago, tanto para espécies nativas como não nativas. Diferenças espaciais e temporais significativas foram verificadas para a riqueza, tanto para espécies nativas como não nativas, entretanto o índice de diversidade de Shannon, mostrou diferenças significativas somente para as espécies nativas. A composição e estrutura da assembleia de peixes nativos e não nativos, apresentaram diferenças significativas ao longo do gradiente longitudinal do rio Iguaçu. As variáveis físicas e químicas (temperatura da água, transparência da água, pH e condutividade elétrica), foram significativas para a separação dos reservatórios ao longo do gradiente longitudinal. A análise de Procrustes mostrou que existe associação entre as variáveis físicas e químicas, e o arranjo espacial da composição e estrutura da assembleia de peixes nativos.
Britton-Simmons, Kevin. "Establishment, spread, and impact of the introduced Japanese seaweed, Sargassum muticum, in the San Juan Islands, Washington /." 2003. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3108062.
Повний текст джерелаMendes, 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.
Повний текст джерелаAs 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.
Hladík, Marek. "Studie ekosystémových dopadů invaze bolševníku velkolepého (Heracleum mantegazzianum)." Master's thesis, 2011. http://www.nusl.cz/ntk/nusl-297259.
Повний текст джерелаLee, Marissa Ruth. "Leaf Traits, Neighbors, and Abiotic Factors: Ways That Context Can Mediate the Impact of Invasive Species on Nitrogen Cycling." Diss., 2016. http://hdl.handle.net/10161/12143.
Повний текст джерелаSpecies invasions are more prevalent than ever before. While the addition of a species can dramatically change critical ecosystem processes, factors that mediate the direction and magnitude of those impacts have received less attention. A better understanding of the factors that mediate invasion impacts on ecosystem functioning is needed in order to target which exotic species will be most harmful and which systems are most vulnerable. The role of invasion on nitrogen (N) cycling is particularly important since N cycling controls ecosystem services that provision human health, e.g. nutrient retention and water quality.
We conducted a meta-analysis and in-depth studies focused on the invasive grass species, Microstegium vimineum, to better understand how (i) plant characteristics, (ii) invader abundance and neighbor identity, and (iii) environmental conditions mediate the impacts of invasion on N pools and fluxes. The results of our global meta-analysis support the concept that invasive species and reference community traits such as leaf %N and leaf C:N are useful for understanding invasion impacts on soil N cycling, but that trait dissimilarities between invaded and reference communities are most informative. Regarding the in-depth studies of Microstegium, we did not find evidence to suggest that invasion increases net nitrification as other studies have shown. Instead, we found that an interaction between its abundance and the neighboring plant identify were important for determining soil nitrate concentrations and net nitrification rates in the greenhouse. In field, we found that variability in environmental conditions mediated the impact of Microstegium invasion on soil N pools and fluxes, primarily net ammonification, between sites through direct, indirect, and interactive pathways. Notably, we detected a scenario in which forest openness has a negative direct effect and indirect positive effect on ammonification in sites with high soil moisture and organic matter. Collectively, our findings suggest that dissimilarity in plant community traits, neighbor identity, and environmental conditions can be important drivers of invasion impacts on ecosystem N cycling and should be considered when evaluating the ecosystem impacts of invasive species across heterogeneous landscapes.
Dissertation
Hu, Li-Yuan, and 胡皪元. "Impacts of the Heavy Metals Invasion on Mechanisms of Biological Phosphorus Removal under Short-Term Temperature Conditions." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/68427391074215741888.
Повний текст джерела國立暨南國際大學
土木工程學系
96
This study mainly investigated the effects of heavy metal category(Zn2+、Cu2+)and concentration (0~2 mgl-1) on the anaerobic/aerobic reactions, including phosphorus release/uptake, polyhydroxyalkanoates (PHAs) synthesis/degradation, and total intercellular glycogen (carbohydrate) synthesis/degradation of the activated sludge under short-term temperature conditions. The performance of the B-SBR activated sludge, which was acclimated by the condition of sludge retention time (SRT) 10 days until reaching steady state, maintained the removal ratios of COD and PO43--P above 90%. In order to realize the operational strategy for EBPR system under metal(s) invasion situation, the performances of batch experiments of phosphate release and uptake, PHAs synthesis/degradation, and total intercellular glycogen synthesis/degradation were used as indicators to investigate the effects of heavy metal category and concentration on phosphate removal ability and toxic inhibition of microorganisms under different temperature conditions (10℃~30℃). Results of batch experiments under the condition of without any metal addition showed that specific substrate utilization rate(SSUR), specific release/uptake phosphorus rates(SPRR,SPUR), PHAs and intercellular glycogen synthesis/degradation rates were increased with the increase of the temperature . However, the microorganisms in aerobic phase lost the ability to degrade PHAs under 10℃ situation. In addition, the temperature order of the tolerant ability of microorganisms to heavy metals invasion was 20℃>30℃>10℃. On the other hand, toxicity of Zn2+ was greater than that of Cu2+. It was also found in the study that, the microorganism was unable to decompose the intercellular carbohydrate to provide the energy (NADH2) needed for synthesizing PHAs while the intercellular carbohydrate decomposition mechanism was suppressed by heavy metal(s). This phenomenon might be the major reason resulting in insufficient production of PHAs for phosphate uptake and the decrease of total intercellular glycogen synthesis rate in aerobic phase. In addition, the existence of heavy metal(s) also influenced the decomposition of PHAs in aerobic phase. At the same time, the phosphate removal ability was further deteriorated due to the insufficient of intercellular carbohydrate and external toxic inhibition. Thus, it could be known that the increase or decrease of PHAs and total intercellular carbohydrate was influenced and impeded by each other both in anaerobic/aerobic phase.
Lin, Jyun-Yen, and 林俊延. "Impacts of the Heavy Metals Copper Invasion on Enzymatic Kinetic Reaction in Biological Phosphorus Removal under Different Temperature Conditions." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/48754861170060006403.
Повний текст джерела國立暨南國際大學
土木工程學系
97
The purpose of this study mainly investigated the effects of heavy metals copper invasion on phosphorus release/uptake, polyhydroxyalkanoates(PHAs)synthesis/ degradation, and intercellular enzymatic activity of Acetyl-CoA Synthetase and Polyphosphate Kinase of the activated sludge during the anaerobic/aerobic reactions under short-term temperature conditions. The efficiency of the activated sludge of B-SBR system which was acclimated until steady state basing on the condition of sludge retention time(SRT)10 days showed that the removal ratio of COD and PO43--P could be maintained above 90%. In order to realize the optimal operation in EBPR system when heavy metal invaded, this study focused on the mechanism of phosphate release/uptake, PHAs synthesis/degradation to investigate the effects of microorganism suffering from different copper concentrations (0~4 mgl-1) and temperatures (10℃~30℃). Experimental results showed that under none added heavy metals, the specific substrate utilization rate, specific release/uptake phosphorus rates, PHAs synthesis / degradation rates, and enzymatic activity of Acetyl-CoA Synthetase and Polyphosphate Kinase significantly increased from 10℃ to 20℃ while none of heavy metal was adding; but there was no significant difference bewteen 20℃ and 30℃. In addition, specific substrate utilization rate, specific phosphorus uptake rate, PHAs synthesis/degradation rates, and enzymatic activity of Acetyl-CoA Synthetase and Polyphosphate Kinase were distinctly decreased while concentration of heavy metals increased. However, the addition of copper metal did not influence the mechanism of phosphorus release. This research also discovered two strong relationships between PHAs synthesis rate and enzymatic activity of Acetyl-CoA Synthetase, and between specific uptake phosphorus rate and Polyphosphate Kinase. It was illustrated that the inhibition of PHAs synthesis rate resulted from the temperature or toxicity effect on Acetyl-CoA Synthetase activity. Also, the phenomenon was similar to the relation between specific uptake phosphorus rate and Polyphosphate Kinase activity. In addition, applied of Lineweaver-Burk equation and coefficient of inhibition, it was demonstrated that the type of inhibition was mix-competitive inhibition, and the inhibitor mainly combined with free enzyme when the copper invaded. Thus, it could be known that the low temperature caused the metabolism in organism decreased; and the copper ions occupied the sites for combing enzyme. Besides, polyphosphate in intercellular could carry out the detoxification process when the inhibitor existed. It caused the phosphate continuously released even at aerobic stage. Consequently, this study proved that the mechanism of enhanced biological phosphate removal fluctuated easily by toxic inhibitors invasion.
Major, Heather L. "Impacts of introduced Norway rats (Rattus norvegicus) on least auklets (Aethia pusilla) breeding at Kiska Island, Aleutian Islands, Alaska during 2001-2003 /." 2004.
Знайти повний текст джерелаMiloch, Daniela. "El impacto de la introducción de Salmónidos sobre los anfibios de los pastizales de altura de Sierras Grandes (Córdoba, Argentina)." Bachelor's thesis, 2016. http://hdl.handle.net/11086/5470.
Повний текст джерелаEntre los diversos y complejos factores que afectan negativamente a los anfibios a nivel global, uno de los principales es la introducción de especies exóticas. Onchorrynchus mykiss y Salvelinus fontinalis son peces predadores con gran potencial invasivo que se introdujeron hace casi un siglo en ríos y arroyos de las Sierras Pampeanas Centrales (SPC), Argentina. El objetivo de este trabajo es comparar los requeri mientos de hábitat de las truchas con los de cuatro especies de anfibios (Rhinella arenarum, Rhinella achalensis, Hypsiboas cordobae y Odontophrynus achalensis) que utilizan arroyos de los pastizales de altura de las SPC y evaluar el impacto de cada especie de predador sobre la ocurrencia y abundancia de estas especies. Se realizaron 126 transectas en ríos y arroyos de los pastizales de altura de las SPC en las que se registró ocurrencia y abundancia de peces y anfibios así como también variables de hábitat. Los requerimientos de hábitat para cada especie fueron caracterizados y comparados mediante métodos multivariados. Para evaluar si los peces introducidos condicionaron la ocurrencia y abundancia de anfibios, se utilizaron Modelos Lineales Generalizados (MLG). Los resultados indican que tanto las truchas como los anfibios del sistema tienen requerimientos de hábitat similares, sin embargo la distribución de dos especies endémicas del sistema (Hypsiboas cordobae y Odontophrynus achalensis) está condicionada por la invasión de peces exóticos. El presente trabajo, aporta evidencia sobre el impacto negativo que generan los salmónidos introducidos sobre dos especies endémicas de las SPC. Esta información podría resultar relevante para considerar el manejo de las poblaciones de salmónidos con fines de conservación para especies de anfibios endémicas y vulnerables.