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Impacts of an herbicide and predator cues on a generalist predator in agricultural systemsWrinn, Kerri M. January 2010 (has links)
Title from second page of PDF document. Includes bibliographical references.
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Predator-prey interactions in the spinifex grasslands of central AustraliaPaltridge, Rachel M. January 2005 (has links)
Thesis (Ph. D.)--University of Wollongong, 2005. / Title from PDF t.p. (viewed on Aug. 13, 2005). Includes bibliographical references.
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Influence of habitat complexity in structuring species-specific interactions and trophic linkages on oyster reefs of southeastern North Carolina /Sonnier, Joseph M. January 2006 (has links) (PDF)
Thesis (M.S.)--University of North Carolina at Wilmington, 2006. / Includes bibliographical references (leaves: 53-59)
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The ecology of yikes! environmental forces alter prey perception of predators /Smee, Delbert Lee. January 2006 (has links)
Thesis (Ph. D.)--Georgia Institute of Technology, 2006. / Title from PDF t.p. (viewed on Oct. 28, 2006). Marc Weissburg, Committee Chair ; Mark Hay, Committee Member ; Lin Jiang, Committee Member ; David Dusenbery, Committee Member ; Don Webster, Committee Member. Includes bibliographical references (p. 115-122).
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Divergent anti-predator strategies and risk allocation in juveniles of three North Pacific flatfishes /Boersma, Kate S. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 57-62). Also available on the World Wide Web.
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Interspecific interactions between the introduced Atlantic crab Rhithropanopeus harrisii and the native estuarine crab Hemigrapsus oregonensis in Coos Bay, OregonJordan, James Robertson, 1965- January 1989 (has links)
Typescript.
Includes vita and abstract.
Bibliography: Includes bibliographical references (leaves 45-47). / Rhithropanopeus harrisii is an introduced Atlantic crab in Coos
Bay, Oregon. In Coos Bay, it occurs only in the uppermost estuary
where salinities are seasonally low (<1 0/00). Rhithropanopeus
occurs at higher salinities in its native range, and tolerates
higher salinities in the laboratory. A native crab, Hemigrapsus
oregoneos1s, occurs in the estuary, but not as far up into the
oligohaline and freshwater zones as Rb1tbcopanopeus. In laboratory
experiments, adult Hem1grapsus consume juvenile Rhithropanopeus.
Hemjgrapsus is significantly more aggressive than Rhithropanopeus.
The absence of juvenile Rhithropanopeus at field sites where both
species occur suggests that field interactions may be occurring.
Taken together, these results and observations suggest that there
may be a dynamic zone in the estuary where the distribution of Rhithropanopeus is restricted by Heroigrapsus. Rhithropanopeus may
find a refuge from Hemigrapsus in the oligohaline-freshwater Zones
of the estuary, such that Hemigrapsus may be exerting selective
pressure on the Rhithropanopeus population favoring freshwater adapted
individuals.
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Predation on an introduced marine snail by native crabsBaker, Patrick January 1988 (has links)
Typescript.
Includes vita and abstract.
Bibliography: Includes bibliographical references (leaves 55-58). / Ceratostoma ioornatum is an introduced marine snail in Puget Sound,
Washington. Two of five native species tested as possible predators ate
Ceratostoma. These two species, the crabs Cancer gracilis and
Lopbppaoopeys bellys, did not eat native snails similar to Ceratpstpma,
but ate native and introduced bivalves more than Ceratpstpma. The
reasons for the differences in predation seemed to be explained by shell
strength of the prey species. The presence of Ceratpstpma adds a new
type of prey to the menu of the two crab species
at the sites studied.
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Estudo da remoção de cistos de Giardia spp. e oocistos de Cryptosporidium spp. e avaliação da microfauna em estações de tratamento de esgoto : instrumentos de avaliação e controle do processo / Removal study of Giardia spp. and Cryptosporidium spp. and characterization of microfauna in wastewater treatment plants : assessment instruments and process controlGreinert-Goulart, Juliane Araújo, 1977- 23 August 2018 (has links)
Orientadores: Regina Maura Bueno Franco, Isabel Cristina Vidal Siqueira de Castro, Edson Aparecido Abdul Nour / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-23T10:51:12Z (GMT). No. of bitstreams: 1
Greinert-Goulart_JulianeAraujo_D.pdf: 4997738 bytes, checksum: fddca06ec1f7089f7c5092bfde151876 (MD5)
Previous issue date: 2013 / Resumo: Os protozoários Giardia spp. e Cryptosporidium spp. são importantes patógenos de veiculação hídrica e são responsáveis por diversos surtos epidêmicos relacionados ao consumo de água contaminada. O estudo da remoção de patógenos e da microfauna que compõem sistemas combinados anaeróbio/aeróbio ainda é incipiente no mundo. Este trabalho teve como objetivo Estudar a remoção de cistos de Giardia spp. e oocistos de Cryptosporidium spp. e avaliar a microfauna do sistema combinado anaeróbio/aeróbio de dois sistemas de Tratamento de Esgoto. Na ETE Piçarrão foram colhidas amostras de esgoto bruto, efluente e lodo do Reator Anaeróbio de Fluxo Ascendente (RAFA), lodo recirculado do tanque de aeração, efluente tratado e lodo condicionado e, da estação de tratamento de esgoto em escala de bancada foram colhidas amostras do lodo do filtro anaeróbio, lodo do biofiltro aerado submerso e lodo do decantador e efluente tratado. Os cistos e oocistos foram concentrados mediante centrifugação e filtração em membrana, empregou-se a reação de imunofluorescência direta e confirmação dos protozoários utilizando o corante vital DAPI e DIC. Para a análise da microfauna foram colhidas amostras de lodo ativado do tanque de aeração e do líquido obtido do biofiltro aerado submerso. A análise quantitativa dos micrometazoários e dos protozoários foi realizada em câmara de Sedgwick-Rafter. A análise qualitativa incluiu observação in vivo, culturas e técnicas ciliatológicas. A ETE Piçarrão apresentou eficiências de remoção de cistos de Giardia spp. que variaram de 99,8 a 100%, sendo observadas altas concentrações de cistos de Giardia spp. no esgoto bruto com uma média de 98.333 cistos/L, sendo que a maior parte dos cistos foi removida pelo RAFA e concentrou-se no lodo condicionado. Oocistos de Cryptosporidium spp. foram detectados em apenas 3 meses na ETE Piçarrão e cistos de Giardia spp. foram detectados em todos os 24 meses de análises. O sistema em escala de bancada apresentou eficiência de remoção de praticamente 100% durante todo o estudo demonstrando que a combinação de sistemas anaeróbio/aeróbio, além de remover nutrientes, também contribui para remoção destes parasitos. O sequenciamento das amostras positivas para Cryptosporidium spp. resultou em perfis compatíveis com as espécies C. hominis e C. parvum e para Giardia spp. em perfis compatíveis com a espécie G. duodenalis assembleias AII e BIV. A microfauna do lodo ativado da ETE Piçarrão é diversificada e composta principalmente por organismos indicadores de boas condições operacionais. A microfauna do sistema em escala de bancada que visava remoção de nitrogênio teve composição diferente com relação às espécies e as abundâncias se comparados com aqueles encontrados em sistemas de lodos ativados convencional. Os ciliados Euplotes aediculatus e Sterkiella cavicola isolados da ETE Piçarrão demonstraram potencial predatório sobre oocistos de Cryptosporidium e cistos de Giardia. O estudo da remoção destes parasitos patogênicos ressalta a importância do tratamento de esgotos sanitários para redução do impacto dos efluentes gerados no meio ambiente e na saúde pública; a necessidade de maior controle quanto ao tratamento de lodo condicionado e a utilização da microfauna como uma importante ferramenta na avaliação do desempenho de sistemas de tratamento de esgoto / Abstract: Giardia spp. and Cryptosporidium spp. are important waterborne pathogens responsible for several outbreaks related to consumption of contaminated water. Due to its long-term survival and peculiar behavior during sewage treatment, changes in system performance may result in decreased removal of these protozoa. Removal of pathogens and study of microfauna from combined system anaerobic / aerobic are still incipient in the world. This work aimed to study the removal of Giardia spp. cysts and Cryptosporidium spp. oocysts and evaluate the microfauna of the aerobic system of two wastewater treatment systems. Samples of the WWTP Piçarrão were collected from raw sewage, UASB effluent, UASB sludge, recirculated sludge from the aeration tank, treated effluent and conditioned sludge. Samples of the system bench scale were collected from the anaerobic filter sludge, submerged aerated biofilter sludge and sludge from the clarifier and the treated effluent. The cysts and oocysts were concentrated by centrifugation and membrane filtration. Protozoa were searched using the direct immunofluorescence assay and confirmation of protozoa using the vital dye DAPI and DIC. Samples were taken from the activated sludge of aeration tank and the liquid obtained from the submerged aerated biofilter for the analysis of the microfauna. Quantitative analysis of small metazoans and protozoan were held in Sedgwick-Rafter chamber. Predation assays were performed with ciliates from the two systems studied. WWTP Piçarrão showed removal efficiencies of Giardia spp. ranging from 99.8 to 100%. Raw sewage presented high concentrations of Giardia spp. (average of 98,333 cysts / L). The majority of cysts were removed by UASB and concentrated in the conditioned sludge emphasizing the importance of proper treatment of this residue. Cryptosporidium spp. was detected in 3 months in WWTP Piçarrão and Giardia spp. was detected in all 24 months of analysis. The combined system bench scale attained almost 100% of removal efficiency during the monitoring period demonstrating that the combination of anaerobic / aerobic systems contributes to removal of these parasites. All samples tested positive for Cryptosporidium spp. by immunofluorescence were also positive by PCR. The sequencing reaction resulted in profiles compatible with the species C. hominis and C. parvum, compared to homologous sequences available in GenBank database and Giardia spp. resulted in profiles supporting the species G. duodenalis assemblage IIA and BIV. The microfauna of the activated sludge from the WWTP Piçarrão are diverse and composed mainly of indicator organisms of good operating condition. Microfauna of the bench scale system, which aimed nitrogen removal, had different composition concerning the species and its abundance when compared with those found in conventional activated sludge systems. Free-living ciliates Euplotes aediculatus and Sterkiella cavicola isolated from WWTP Piçarrão demonstrated predatory potential for Cryptosporidium spp. oocysts and Giardia spp. cysts. This study underscores the importance of sewage treatment to reduce the impact of effluents generated in the environment and in public health; the need for greater control regarding the treatment of conditioned sludge generated in sewage treatment plants and the use of microfauna as an important tool for assessing the performance of wastewater treatment systems / Doutorado / Parasitologia / Doutora em Parasitologia
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The feeding ecology and habitat use of lions reintroduced to small, enclosed reserves in the Eastern Cape Province, South AfricaRapson, Jackie Anne January 2005 (has links)
Lions have recently been introduced to a number of small (<300km²), enclosed reserves in the Eastern Cape Province as a draw-card for tourists. However, there have been few studies of lion behaviour or predator prey interactions within small reserves. Thus the aim of this study is to contribute towards a better understanding of the effects of space on diet and habitat use of re-introduced lions. The research was conducted at two small private reserves, Shamwari and Kwandwe. Kills were mostly large (55%, >120kg), adult (41%) and male (39%) and the five most commonly killed species (kudu, black wildebeest, warthog, bushbuck and Blesbuck) comprised 67.9% of all kills and 67.8% of total biomass consumed. In an attempt to overcome the problem of gaps in the kill lists, a subset of data, which excluded kills more than five days apart, was analyzed and this gave similar results to analysis of the full kill lists. Mean daily intake rates varied annually between 2.26 and 5.23kg.FEQ⁻¹ for the full data set and 4.53 and 1 0.46kg.FEQ⁻¹ for the subset. The difference between estimated (calculated using daily intake rates of 5 and 7.12kg.FEQ⁻¹) and observed offtake for each ungulate species reflected the preference ratings for that species. Analysis of bone marrow indicated that: lions killed ungulates in moderate to good condition; condition of culled animals was lower than that of kills; distal bones could be used in analyses; and that that bones exposed to the environment for at least a week could be used to analyze condition of prey. Home ranges and activity centers ranged from 21.42km² to 73.27km² and 2.7lkm² to 17.47km² respectively, which was smaller than expected from previous studies. Although, lions at K wandwe and Shan1wari preferred different vegetation types, at both reserves they generally occupied areas that were structurally similar to what has previously been reported. Continuous monitoring and analyses of diet, including condition of the prey, and habitat use will provide reserve managers with some of the necessary information to enable them to effectively manage their lion populations and to predict and minimize potential problems.
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Modelling dispersal processes in impala-cheetah-lion ecosystems with infection in the lionsMbava, Willard January 2016 (has links)
The study involved the predator-prey interaction of three species namely the predator (Cheetah Acinonyx jubatus), the super-predator (Lion Panthera leo), and their common prey (Impala Aepyceros melampus). The study area is the Kruger National Park. The predator being an endangered species, faces a survival problem. It is frequently killed by the super-predator to reduce competition for prey. The super-predator also scares away the predator o_ its kills. The prey forms the main diet of the predator. The plight of the predator motivated the author to formulate disease and reaction-diffusion models for the species interactions. The purpose of the models were to predict and explain the effect of large competition from the super-predator on the predator population. Important parameters related to additional predator mortality due to presence of super-predator, the disease incidence rate and induced death rate formed the focal points of the analysis. The dynamics of a predator-prey model with disease in super-predator were investigated. The super-predator species is infected with bovine Tuberculosis. In the study, the disease is considered as biological control to allow the predator population to regain from low numbers. The results highlight that in the absence of additional mortality on the predator by the super-predator, the predator population survives extinction. Furthermore, at current levels of disease incidence, the super-predator population is wiped out by the disease. However, the super-predator population survives extinction if the disease incidence rate is low. Persistence of all populations is possible in the case of low disease incidence rate and no additional mortality imparted on the predator. Furthermore, a two-species subsystem, prey and predator, is considered as a special case to determine the effect of super-predator removal from the system, on the survival of the predator. This is treated as a contrasting case from the smaller parks. The results show that the predator population thrives well in the total absence of its main competitor, with its population rising to at least twice the initial value. A reaction-diffusion three-species predator-prey model was formulated and analysed. Stability of the temporal and the spatio-temporal systems, existence and non-existence of stationary steady state solutions were studied. Conditions for the emergence of stationary patterns were deduced. The results show that by choosing the diffusion coeffcient d2 > _D 2 suffciently large, a non-constant positive solution is generated, that is, stationary patterns emerge, depicting dispersal of species. Predators were observed to occupy habitats surrounding prey. However, super-predators were observed to alternate their habitats, from staying away from prey to invading prey habitat. In the investigation, strategies to determine ways in which the predator species could be saved from extinction and its population improved were devised, and these included isolation of the predator from the super-predator.
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