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 20 of 50 for “"predation pressure"”.
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A Study of factors influencing a non-cyclic, island population of snowshoe hares
… that on the adjacent mainland. Hare densities, predation rates, reproduction and juvenile survival were all monitored on both Jacquot Island and mainland study areas. Habitat on the study sites was also examined for cover and browse availability. Jacquot Island juveniles had survival rates 3-15 …
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Anti-predator behaviour of Cape fur seals Arctocephalus pusillus pusillus in relation to predation by white sharks Carcharodon carcharias around Seal Island, False Bay, South Africa
… Africa, where recently quantified patterns of predation pressure by white sharks Carcharodon carcharias on Cape fur seals Arctocephalus pusillus pusillus suggested a landscape of fear particularly apposite to this.
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Causes and consequences of mortality and mutilation in the Cape Peninsula baboon population, South Africa
… revealed a baboon population under severe human predation pressure with high levels of permanent injury and mortality, in addition to an adult sex ratio strongly biased towards females. There was no data on the causes or the distribution of deaths and permanent injuries on the Peninsula to inform …
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Effect of Lion Calls on African Elephants (<i>Loxodonta Africana</i>) in Addo Elephant National Park, South Africa
<p>Perceived predation risk alters animals’ behavior. This shift in behavior often comes at the cost of attaining resources. Generally, African elephants (<em>Loxodonta africana</em>) experience little predation pressure; however, the risk of predation by lions (<em>Panthera leo</em>) increases …
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Aspects of the ecology of migrant shorebirds (Aves: Charadrii) at the Berg River estuary, South Africa
… The high density of birds results in a high predation pressure. Although the rate of prey removal by birds is one of the highest recorded in the east Atlantic, it represents only 17% of the annual production of invertebrates. A bird-exclusion experiment confirmed that birds have little impact …
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Using spatial methods to analyse anthropogenic predation risk and movement ecology of white-tailed deer (Odocoileus virginianus)
… behaviour of White-tailed deer in response to predation pressure from human hunters in combination with the biotic and abiotic drivers of predation risk and flight response. Giving wildlife managers greater understanding to influence deer populations, and landscapes, in the future.
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Sponge Community Structure and Anti-Predator Defenses on Temperate Reefs of the South Atlantic Bight
The interaction between predation and anti-predator defenses of prey is important in shaping community structure in all ecosystems. This study examined the relationship between sponge predation and the distribution of sponge anti-predator defenses on temperate reefs in the South Atlantic Bight. …
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Effects of Avian Predators on Stream Fish Assemblages
… can be used to successfully manipulate avian predation pressure. The third chapter uses this technique to examine what effects kingfishers and wading birds are having on stream fish assemblages, and shows that there are effects are on two of the most abundant minnow species, striped shiners …
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INVASION DYNAMICS OF FRESHWATER CRAYFISH IN A MAN-DOMINATED LAND: SPATIO-TEMPORAL, ECOLOGICAL AND HUMAN DIMENSIONS
… with A. pallipes, suggesting stronger predation pressure or indirect effects of the invasive species on resource availability, due to the contrasting functional roles of native versus alien crayfish. Finally, the human dimension in protected areas was explored through visitor surveys in …
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Using parasite communities to discriminate between sympatric morphs of threespine sticklebacks (Gasterosteus aculeatus) in lake Þingvallavatn, Iceland
… that reflect environmental factors like predation pressure and diet. This study explores the potential of parasites as indicators of ecotype differentiation. Fish of three ecotypes of threespine sticklebacks from lake Þingvallavatn (lava, mud and deep-water) were examined for parasites …
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Learning of Dietary Cues By Embryos and Larvae of Ringed Salamanders (Ambystoma Annulatum)
… embryos to learn can prepare them for selective pressures, such as food availability and predation pressure, they will face after hatching. I tested the hypothesis that larval ringed salamanders (Ambystoma annulatum) exposed to a novel food scent as embryos will exhibit a preference for the scent …
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Variation in Behavior of Different Populations and Sex Classes of Paedomorphic Oklahoma Salamanders
… factors interact to create unique selection pressures that influence the behavior of individuals both within and among populations. Intrinsic differences in body size, age, sex, and reproductive status can contribute to behavioral variation among conspecifics. Environmental influences include …
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Behavioral, temporal, and spatial relationships in free-ranging female Anolis carolinensis (Sauria: Polychridae)
… but rarely during courtship (2%) or copula (7%). Predation pressure was minimal as only four predator avoidances were observed. Home range volume and area for males averaged 68.5 m³ and 50.5 m², respectively. For females, home range volume and area were considerable smaller than males, averaging …
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Zooplankton population variability in a warming ocean: Modeling spatiotemporal patterns and drivers within a dynamic shelf ecosystem
… in fall populations due to density-dependent predation pressure. Finally, through the detection of dynamic interactions, we find that C. finmarchicus trophic structure changes both seasonally and spatially, which highlights the complexity of zooplankton population responses to biotic drivers …
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Predator Behavior and Prey Demography in Patchy Habitats
… The potential positive effects of reduced predation pressure from M. flagellum that may accompany loss and fragmentation of Florida scrub is likely to be offset by increased predation rates by habitat and dietary generalist predators that incidentally prey upon S. woodi. Despite the …
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Genomic adaptation to a century of environmental change in zooplankton from the Canadian Shield
… repeatability of native prey responses to novel predation pressure on a phenotypic and genetic level. Chapter 3 re-examines the introduction and spread of Bythotrephes in the Canadian Shield and presents new evidence from microfossils, sediment DNA, and radiocarbon dating to suggest an earlier …
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Using Conditioned Food Aversion (CFA) to reduce Pied Crow (Corbus albus) predation of plover nests
Nest predation is one of the principle constraints on bird breeding success, accounting for 20 to 80% of all nest failures. It can be exacerbated by anthropogenic factors and the resultant increased predation pressure has caused the decline of numerous bird species worldwide. Identifying management …
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Landscape-scale mechanisms of biological pest control in a South Korean agricultural landscape
… model, the consequences for pests of intraguild predation (IGP) between enemies were found to depend on landscape complexity. In landscapes with high amounts of seminatural habitat and low spatial autocorrelation (high configurational complexity), IGP by vertebrate predators led to a release of …
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