Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 14 of 14 for “"propagule pressure"”.
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The eco-evolutionary consequences of multiple introductions for colonizing individuals
… shifts, and reintroductions of rare species. Propagule pressure, which comprises the number of introduction events (propagule number) and the number of individuals per introduction event (propagule size), consistently correlates with a greater probability of population establishment. It is …
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Regional Rarity: Consequences of Dispersal Limitation and Strategies for Reintroduction
… contribute to rarity, including species traits, propagule limitation, ecological requirements, and population level processes such as demographic and environmental stochasticity. Yet, our understanding of species rarity remains limited since few studies have examined how these factors act in …
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Ecological implications of introducing Leucaspius delineatus (Heckel, 1843) and Pseudorasbora parva (Temminck and Schlegel, 1842) into inland waters in England
… The drift dynamics, i.e. timing and intensity (propagule pressure), of sunbleak and topmouth gudgeon were assessed for source populations to determine dispersal potential. Potential risks for native species posed by these two alien cyprinids were assessed with respect to the parasite fauna and …
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Determinants of native and exotic plant species diversity and composition in remnant oak savannas on southeastern Vancouver Island
… different ways. Roads increase both exotic propagule pressure and disturbance, which may facilitate exotic invasion. In contrast, disturbance from roads may increase the likelihood of local extinction for particular natives. Differing climatic preferences within the native and exotic species …
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Biodiversity impacts of Chilean needle grass Nassella neesiana on Australia’s indigenous grasslands
… intact grassland was not invaded, even with high propagule pressure. Gaps of c. 1 m (as opposed to 10-30 cm) were required for establishment. Pin transect sampling demonstrated that increased senescence of Themeda triandra swards correlated with greater invasion. Nassella neesiana was found to …
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Pattern and process of plant invasion in an African savanna ecosystem, with emphasis on multiple spatial and temporal scales
… input into general theories, such as the role of propagule pressure. These components together provide insight into the dynamics of alien plant invasions in an African savanna and protected area system.
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Temporal trends in stream-fish distributions, and species traits as invasiveness drivers in New River (USA) tributaries
… life history. Variables estimating human use and propagule pressure were non-informative. Traits that influenced invasion success were consistent with the hypothesis that human land-use practices have increased the invasibility of highland watersheds by creating novel conditions suited to lowland …
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Allee effects and the persistence of small populations
… evidence is limited. Additionally, social pressure is demanding alternative ‘greener’ tools to achieve eradication of new incursions. The Allee effect is defined as a positive relationship between population size and fitness and is an important factor that underpins the widespread effect of …
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Use of genetic methods for determining patterns and processes during marine biological invasions
… faster and more frequent transoceanic shipping, propagule pressure in the marine environment is likely to further increase, leading to a need for effective strategies for the early detection, prevention and control of marine invasive species. However, such strategies are often difficult to …
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Invasive species: fundamental and applied science
… an adapted version of RIP that incorporates propagule pressure. T. s. scripta was found to have high impact, corroborating its now banned status in the EU, but still a high risk. In Chapter 6, I assess the potential impacts of two readily available fish species in the pet trade: Tanichthys …
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Undercover predators: Vegetation mediates foraging, trophic cascades, and biological control by omnivorous weed seed predators
<p>Weed pressure is the most costly challenge that vegetable growers face, requiring more labor investment than other production inputs. Vertebrate and invertebrate seed predators destroy a large percentage of weed propagules on the soil surface, and their ecosystem services may ease labor …
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Assessing the vulnerability of Antarctic marine ecosystems to invasive non-native species
… greater colonisation (species richness) and propagule pressure (individual abundance) than exposed areas of the hull. The composition of the biological communities did not differ among exposed and niche areas, but did change significantly among the three surveys conducted. Only six species …
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The evolution of caste-specific morphology and colony structure in ants
… a combination of adaptation to ecological pressures and historical constraints. My research goals were to investigate intra and interspecific variation in caste specific morphology and colony structure in a comparative framework to understand how traits evolve relative to species’ ecology. …