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Valuing invasives understanding the Merremia peltata invasion in post-colonial Samoa /Kirkham, William Stuart, Doolittle, William Emery, Knapp, Gregory W., January 2005 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2005. / Supervisors: William Doolittle and Gregory Knapp. Vita. Includes bibliographical references.
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The identification and characterization of Caecidotea racovitzai (Isopoda) as the ecologically important second intermediate host of the invasive trematode Leyogonimus polyoon (Trematoda), and aspects of the natural history of each on Shawano Lake, Wisconsin /Zellmer, Patricia J. January 2009 (has links) (PDF)
Thesis (M.S.)--University of Wisconsin--Stevens Point, 2009. / Submitted in partial fulfillment of the requirements of the degree Master of Science in Natural Resources (Wildlife), College of Natural Resources. Includes bibliographical references (leaves 167-174).
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Mechanisms of species invasion in apple snails: proteome of the egg perivitelline fluid, and proteomic responses of the adults to abiotic stressorsMu, Huawei 01 September 2016 (has links)
The Pomacea apple snails are amphibious operculate freshwater gastropods. They exhibit different stress tolerant abilities as some of them are invasive (e.g., Pomacea maculata and Pomacea canaliculata) and others are non-invasive species (e.g., Pomacea diffusa). By using a comparative approach, I have profiled the perivitelline fluid of P. maculata, compared the physiological and proteomic responses of P. canaliculata and P. diffusa to thermal and hypoxic stressors, and examined their sequence divergences. 74 proteins were identified from the PVF of P. maculata. Comparison of gene expression levels between albumen gland (the organ that secrets PVF) and other organs showed that 24 PVF genes were specifically expressed in albumen gland. Base substitution analysis of PVF and housekeeping orthologs between P. maculata and its congener P. canaliculata showed that these reproductive genes have higher evolutionary rate. The LT50 of P. canaliculata was significantly higher than that of P. diffusa. More than 3,350 proteins were identified from the hepatopancreas of the snails exposed to acute and chronic thermal stress using iTRAQ-coupled mass spectrometry. Chronic exposure caused differential expression of more proteins, with many of them related to restoration of damaged molecules, ubiquitinating dysfunctional molecules, and utilization of energy reserves in both species; but only in P. diffusa there was a shift from carbohydrate to lipid catabolism. Analysis of orthologous genes encoding the differentially expressed proteins revealed nine candidate genes may have undergone positive selection (Ka/Ks > 0.5). A 72 h mortality experiment showed that P. canaliculata is much more tolerant to hypoxia than P. diffusa. The two species were then exposed to four levels of dissolved oxygen (6.7, 4.1, 2.0 and 1.0 mg O2 L-1) for 8 h, and their gill proteins were analyzed using iTRAQ-coupled LC-MS/MS. Compared with P. diffusa, P. canaliculata had more up-regulated signal transduction proteins and down-regulated proteins which are involved in glycolysis and the tricarboxylic acid cycle. Evolutionary analysis indicated that selection has acted on some of the hypoxia responsive genes. The comparative method and results provide a framework for studying the genetic basis of species invasion and predicting their further expansion in a changing climate for non-model species.
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TRAITS UNDERLYING INVASIVENESS: A COMPARISON OF WIDESPREAD AND ENDEMIC SPECIES IN THE GENUS GAMBUSIA (POECILIIDAE)Rehage, Jennifer Schopf 01 January 2003 (has links)
Due to the irreversible nature of biological invasions, prediction has been a key area of emphasis in invasion biology. Specifically, the degree to which species-specific traits may help us predict invasion success is a core issue in the field. My research examined a series of traits and asked whether they were good predictors of invasion success, particularly establishment success. I compared traits among four species of the poeciliid fish Gambusia, two of them highly invasive (G. affinis and G. holbrooki) and two of them non-invasive (G. hispaniolae and G. geiseri).I examined abiotic tolerances, feeding behavior, behavioral responses to novel predation and competition, life histories, and dispersal tendencies. I found the invasive Gambusia species to be more tolerant of low temperatures and to exhibit higher feeding rates and dispersal tendencies than non-invasives. Invasive species were more likely to respond appropriately to novel predation by reducing foraging and activity level and by increasing refuge use, and less likely to show lower foraging success when faced with competitors. Invasives exhibited higher fecundity and juvenile growth rates, and consequently reached maturity sooner than non-invasives. I found no differences in the species' diet breadth or aggressiveness.I then simulated the invasions of simplified pond communities and measured establishment success (with and without novel competitors) and community impact by tracking population trajectories over several months. As predicted from the trait comparisons, I found that in both simulations invasive Gambusia outperformed non-invasives by achieving andvmaintaining larger populations. In the first experiment, only invasive Gambusia were able to successfully establish (non-invasive populations had zero survival). In the second experiment, invasive Gambusia populations were better able to cope with competition and had greater community impact on lower trophic levels than the non-invasives.Overall, species traits were good predictors of establishment success. A species' ability to cope with the abiotic conditions of the invaded community seemed particularly important to whether or not establishment occurred in the study communities. Life history traits and the species' ability to cope with biotic interactions were important to determining the level of establishment species achieved if invaders survived the novel abiotic element.
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Assessing impacts of the Aquatic Invaders in Maine (AIM) workshop on inquiry pedagogy and student learning /Miniutti, Danielle, January 2009 (has links)
Thesis (M.S.) in Teaching--University of Maine, 2009. / Includes vita. Includes bibliographical references (leaves 108-117).
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Arthropod assemblages in a savanna invaded by Opuntia stricta (Cactaceae) in the Kruger National Park, South AfricaHarris, Kyle Robert. January 2009 (has links)
Thesis (M. Sc.(Zoology and Entomology))--University of Pretoria, 2009. / Summary in English.
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The role of stress tolerance on marine invasive musselsMa, Wai-lung, 馬惠龍 January 2013 (has links)
Marine bioinvasion has been increasing exponentially due to intensive human activities. To manage the threats posed by marine bioinvasion, it is important to understand the key factors for invasion success. Stress tolerance is thought to play an important role in the invasion process, however, little is known of the nature of this tolerance, particularly whether stress tolerance is species- or population-specific. To determine this, laboratory experiments were conducted to investigate differential tolerance of populations of a cosmopolitan marine invasive mussel, Perna viridis, and whether stress tolerance can be altered through pre-selection of individuals. Comparisons were firstly made between two local P. viridis populations from the intertidal and subtidal zones to test if stress tolerance was population-specific. Individuals from the intertidal population had higher baseline heart rates, lower critical salinity values, Scrit, for cardiac activity and longer survival duration at low salinity than individuals from the subtidal population, supporting the presence of population level differences in stress tolerance. Mortality of P. viridis was also compared at sites in both their introduced range (Hong Kong) and native range (Indonesia) which revealed that individuals from the Hong Kong population were more stress tolerant than their native counterparts in Indonesia. Using the same experimental approach, the effect of pre-selection to stress (a prior pre-selection to hypoxia and a subsequent exposure to heat) showed that stress tolerance can be enhanced by pre-selection. The second part of this study investigated whether invasive mussels, Brachidontes variabilis and P. virdis, were more stress tolerant than the native, non-invasive, Septifer virgatus. Laboratory experiments compared the Scrit as well as critical temperature, Hcrit for cardiac activity. Mortality and byssus thread production were also measured in a factorial design with different combinations of temperature (16, 24 and 32 °C) and salinity (8, 16, 32 p.s.u) for 15 days. The two invasive mussels had a higher Hcrit and lower Scrit, which indicated a higher stress tolerance, than the non-invasive mussel. The mortality rate of P. viridis was faster than in B. variabilis and S. virgatus at 8 p.s.u. whereas S. virgatus was the only mussel that exhibited mortality in the medium hyposalinity (16 p.s.u.) and showed much slower byssus attachment than the invasive mussels, suggesting that the invasive mussels are more stress tolerant to heat and medium hyposalinity than the non-invasive species. Overall, stress tolerance proved to be higher in the invasive than non-invasive species and was also population-specific with higher stress tolerance in the invasive population, which may be attributed to the selection of more tolerant individuals during the invasion process. Such a process may occur when founding individuals successfully pass through an invasion process, which may increase the overall mean population-level of stress tolerance and explain why invasive species are generally more stress tolerant than native species. Thus stress tolerance plays an important role in invasion success and invasive species with high stress tolerance may be favoured by climate change, including ocean warming and increased precipitation, which may extend their current distribution range. / published_or_final_version / Biological Sciences / Master / Master of Philosophy
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Valuing invasives: understanding the Merremia peltata invasion in post-colonial SamoaKirkham, William Stuart 28 August 2008 (has links)
Not available / text
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Modelling the spread of invasive species across heterogeneous landscapes : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Lincoln University /Pitt, Joel Peter William. January 2008 (has links)
Thesis (Ph. D.) -- Lincoln University, 2008. / Includes case study of Argentine ant in New Zealand. Also available via the World Wide Web.
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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 methodsDudei, Nicole L. January 2009 (has links)
Thesis (M.S.)--Ohio University, August, 2009. / Title from PDF t.p. Includes bibliographical references.
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