Дисертації з теми "Seabird conservation"
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Rollinson, Dominic Paul. "Understanding and mitigating seabird bycatch in the South African pelagic longline fishery." Doctoral thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/25500.
Повний текст джерелаGaglio, Davide. "Investigating the foraging ecology and energy requirements of a seabird population increasing in an intensely exploited marine environment." Doctoral thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/27020.
Повний текст джерелаSawyer, Thomas R. "Habitat use and breeding performance in an inshore foraging seabird, the Black Guillemot Cepphus grylle." Thesis, University of Glasgow, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312131.
Повний текст джерелаMontrond, Gilson. "Assessing sea turtle, seabird and shark bycatch in artisanal, semi-industrial and industrial of fisheries in the Cabo Verde Archipelago." Master's thesis, Faculty of Science, 2021. http://hdl.handle.net/11427/32854.
Повний текст джерелаNupen, Lisa Jane. "A conservation genetic study of threatened, endemic southern African seabirds." Doctoral thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/13387.
Повний текст джерелаMolecular techniques have a broad, and growing, application in the field of wildlife conservation, ranging from the systematic identification and classification of taxa, through studying genetic connectivity between populations, to parentage and individual barcoding. While they are applied to a wide range of spatial- and temporal-scales, molecular approaches complement traditional methods used to classify, investigate and understand the natural world. This study uses multiple lines of evidence, at various scales, to investigate how seabird biology influences population-level responses to changing environments. The focal area is the Agulhas-Benguela Ecosystem (ABE) along the south-western coast of Africa. Globally, biodiversity loss due to environmental change in marine ecosystems is significantly affecting the phenology, distribution, dispersal patterns, and demographic rates of organisms across trophic-levels. Broad-scale changes are occurring that have consequences for both commercial fisheries and threatened marine top-predators. Seabirds are valuable indicators of the state of marine ecosystems, and changes in their distribution and dispersal patterns may reflect those of species in lower trophic-levels. This is the case in the ABE, where some endemic seabird species are better at responding to changes in their environment than others. Twentieth century shifts in the distribution of key pelagic prey species in the ABE have had serious consequences for endemic seabirds. The African Penguin Spheniscus demersus, Cape _ Gannet Moms capensis and Cape Cormorant Phalacrocorax capensis rely on these pelagic fish, and all three species are threatened and in decline. In this study population genetic and phylogeographic methods are used to: (i) quantify levels of genetic diversity, and determine regional-scale structure within all three focal species; (ii) explore fine-scale population structure in African Penguin; and (iii) compare wild and captive populations of African Penguins. The conservation of genetic diversity is essential for the long-term persistence of species. Population genetics can help us to understand the evolutionary processes that have shaped patterns of genetic diversity in the focal species, and predict how they might respond to further environmental changes. Comparative phylogeography, combined with capture-mark- recapture models based on ringing data and annual census counts, provide the most complete picture of the micro-evolutionary forces at play in this unique ecosystem, and highlight seabird life-history characteristics may facilitate adaptation and survival under novel conditions. This is the first conservation genetic study of endemic seabirds in the ABE. Although the three focal species differ in a number of aspects of their breeding and foraging ecology, and in some life-history characteristics, they have evolved under similar selective pressures across their shared range, and represent natural replicates that allow us to determine the dominant drivers of population genetic change. Flexibility in foraging behaviour and the degree of breeding site fidelity exhibited by each of the three focal species affect the rate and effectiveness of their demographic responses to changes in their environment. Understanding connectivity among seabird populations is crucial for their long-term conservation, and has been investigated in numerous studies of seabird species from around the world. Similar to many of these, this study found very low levels of genetic structure among populations of all three focal species based on DNA sequence data, suggesting long-term gene-flow among them, despite potential physical and non-physical barriers. Overall, the patterns observed suggest that high connectivity characterises their breeding regions, and most breeding colonies, buffering the respective populations against environmental variability. These results were supported by fine-scale analyses of the African Penguin using microsatellite markers that also suggested high levels of gene-flow, which may have masked genetic signatures of the regional- and colony-level bottlenecks experienced by this species. Microsatellite-based genetic diversity and fine-scale structure were also compared among wild and captive populations of African Penguins to assess the genetic consequences of a planned conservation breeding program. The genetic composition of birds in captivity largely reflects that found in wild populations. The success of reintroduction in terms of decreasing extinction risk in the wild is uncertain, and should be implemented as part of a broader management plan that addresses the primary threats to wild populations. Further research is required to improve our understanding of many aspects of endemic southern African marine avifauna and better inform our ability to ensure their continued persistence in this system.
Rice, Edward. "Rory lines : silver lining for seabirds in South Africa's demersal trawl fisheries." Master's thesis, University of Cape Town, 2012. http://hdl.handle.net/11427/10902.
Повний текст джерелаSeabird bycatch in commercial fisheries is one of the major factors causing decreases in many seabird populations. In trawl fisheries, high mortalities have been recorded as a result of seabirds being struck by trawl warps (the cables used to tow the trawl net). Tori (bird-scaring) lines have been used to decrease seabird mortality in some trawl fisheries by up to 90%. However, tori lines are not effective at reducing the number of birds that drift towards the trawl warps while feeding on factory discards alongside the vessel. The Albatross Task Force (ATF) helped to develop and test a new device, the Rory Line (RL), to be used in conjunction with tori lines, and designed to reduce warp strikes by placing a physical barrier between the scupper (where factory discards are released) and the danger zone (where the trawl warps enter the water) at the stern of the vessel. This study tests the efficacy of the RL at reducing the number of birds drifting into the danger zone and the number of birds being struck by the trawl warps.
Votier, Stephen C. "Conservation implications of variation in diet and dietary specialisation in great skuas." Thesis, University of Glasgow, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390768.
Повний текст джерелаMartínez, Abraín Alejandro. "Research applied to the Conservation of Seabirds Breeding on Islands of the Western Mediterranean." Doctoral thesis, Universitat de Barcelona, 2003. http://hdl.handle.net/10803/779.
Повний текст джерелаGrecian, William James. "Factors influencing the marine spatial ecology of seabirds : implications for theory, conservation and management." Thesis, University of Plymouth, 2011. http://hdl.handle.net/10026.1/873.
Повний текст джерелаClay, Thomas Anthony. "Drivers of variation in the migration and foraging strategies of pelagic seabirds." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/267809.
Повний текст джерелаAires, Rafaela Magalhães. "Análises genéticas de carcaças de atobá marrom, Sula leucogaster (Boddaert, 1783), da região centro-norte do Estado do Rio de Janeiro." Universidade do Estado do Rio de Janeiro, 2013. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=9044.
Повний текст джерелаA região da Bacia de Campos está exposta a diversas atividades antrópicas, que interferem diretamente no funcionamento do ecossistêmico marinho. O estudo da fauna marinha na costa centro-norte fluminense mostra grande relevância, diversas aves marinhas residem ou passam grande parte de seu período migratório ao longo da Bacia de Campos, entre elas está Sula leucogaster (Boddaert, 1783). Embora essas aves sejam altamente móveis, suas populações apresentam uma estrutura populacional genética robusta. Com o intuito de verificar a estruturação e as relações evolutivas da população de Sula leucogaster na Bacia de Campos foram recolhidas 91 amostras de encalhe e os dados gerados para esta região foram comparados com dados já publicados de outras bacias oceânicas. A partir da região controle do DNA mitocondrial foram gerados 26 haplótipos, todos exclusivos da Bacia de Campos, muitos raros e apenas oito possuíram frequência comum. As análises mostraram que a população da Bacia de Campos é um estoque genético de Sula leucogaster. Tal fato pode ser atribuído ao comportamento filopátrico e ao hábito costeiro dessa espécie que impede o fluxo gênico entre populações. Além disso, a população da Bacia de Campos detém baixa variabilidade genética e possivelmente está sofrendo efeito gargalo ou seleção purificadora, corroborados por valores do teste Fu, o que é comum para espécies que se dividem em subpopulações. Os dados filogenéticos demonstram um contato recente entre as populações da Bacia de Campos e da ilha de Ascensão. As condições oceanográficas também têm influência na estruturação de populações de Sula leucogaster, visto que a ausência de barreiras e a proximidade geográfica poderiam favorecer contato secundário com o Mar do Caribe, fato não evidenciado nas análises. Sendo assim, a divergência de populações nessa espécie e a baixa variabilidade genética são fatores preocupantes para a manutenção da população de atobás marrons em uma área de grande impacto ambiental
The region of Campos Basin is exposed to various anthropogenic activities that affect directly the behavior of marine ecosystem. The study of marine fauna in North-Central coast of Rio de Janeiro is of great importance, several marine and coastal birds live or spend most of their migratory period along the Campos Basin, between them is Sula leucogaster (Boddaert, 1783). Although these birds are highly mobile, their populations have a robust genetic population structure. In order to check the structure and evolutionary relationships of the population of Sula leucogaster in the Campos Basin, 91 stranding samples were collected, and the data of this region were compared with the published data. From the control region of mitochondrial DNA, 26 haplotypes were identified, all of them being unique to the Campos Basin. Most of these haplotypes were rare, only eight have common frequencies. The analyses show that the population of the Campos Basin is a genetic stock of Sula leucogaster. This fact can be attributed to the filopatric behavior and coastal habit of this species that prevents the gene flow between populations. Moreover, the population of the Campos Basin has low genetic variability and is possibly suffering a bottleneck effect or purifying selection, supported by Fu test values, which is common for species divided into subpopulations. The phylogenetic data demonstrates a recent contact between the populations of the Campos Basin and Ascensão island. The oceanographic conditions also influence the structuring of populations of Sula leucogaster populations, as the absence of barriers and geographical proximity could favor secondary contact with the Caribbean Sea, which was not evident in the analyzes. Thus, the low amount of gene flow and the low genetic variability are worrying factors for the maintenance of the population of brown boobies in this area of high environmental impact
Sherley, Richard Brian. "Factors influencing the demography of endangered seabirds at Robben Island, South Africa : implications and approaches for management and conservation." Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.528091.
Повний текст джерелаGressetvold, Marit. "Identifying Conservative Criteria for (environmental) Assessments of Vulnerability; : Seabirds and Offshore Wind Farms as a Case Study." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-23247.
Повний текст джерелаKloser, Rudolf J. "Seabed biotope characterisation based on acoustic sensing." Thesis, Curtin University, 2007. http://hdl.handle.net/20.500.11937/524.
Повний текст джерелаKloser, Rudolf J. "Seabed biotope characterisation based on acoustic sensing." Curtin University of Technology, Faculty of Science and Engineering, Department of Imaging and Applied Physics, 2007. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=18566.
Повний текст джерелаThese ecological terrain types of soft-smooth, soft-rough, hard-smooth and hard-rough were chosen as they were the most relevant to the biota in their ability to attach on or burrow into the seabed. A seabed scattering model supported this empirical relationship and the overall shape of backscatter to incidence angle relationship for soft and hard seabed types. The correlation between acoustic data (backscatter mean and standard deviation) and the visual and physical samples was most consistent between soft-smooth and hard-rough terrain types for a large range of incidence angles (16o to 70o). Using phenomenological backscatter features segmented into 10 common incidence angle bins from -70o to 70o the length resolution of the data decreased to 0.55 times depth. The decreased resolution was offset by improved near normal incidence (0o to 30o) seabed type discrimination with cross validation error reducing from 32% to 4%. A significant relationship was also established between the acoustic data and the dominant functional groups of fauna. Faunal functional groups were based on the ecological function, feeding mode and substrate preference, with 8 out of the 10 groups predicted with 70% correctness by the four acoustically derived ecological terrain types. Restricting the terrain classification to simple soft and hard using the acoustic backscatter data improved the prediction of three faunal functional groups to greater than 80%. Combining the acoustic bathymetry and backscatter data an example region, Everard Canyon, was interpreted at a range of spatial scales and the ability to predict the preferred habitat of a stalked crinoid demonstrated.
Seabed terrain of soft and hard was predicted from the acoustic backscatter data referenced to a common seabed incidence angle of 40o. This method of analysis was selected due to its combined properties of high spatial resolution, consistent between terrain discrimination at the widest range of incidence angles and consistent data quality checking at varying ranges. Based in part on the research reported in this thesis a mid-depth Simrad EM300 multibeam sonar was purchased for use in Australian waters. A sampling strategy is outlined to map all offshore waters with priority within the 100 m to 1500 m depths.
Arcos, Pros José Manuel. "Foraging Ecology of Seabirds at Sea: Significance of Commercial Fisheries in the NW Mediterranean." Doctoral thesis, Universitat de Barcelona, 2001. http://hdl.handle.net/10803/775.
Повний текст джерелаMorera, Pujol Virginia. "Multi-colony approaches to study migratory and foraging strategies in pelagic seabirds." Doctoral thesis, Universitat de Barcelona, 2020. http://hdl.handle.net/10803/668684.
Повний текст джерелаEl moviment és una característica omnipresent en el regne animal, a les més diverses escales espacio-temporals i amb conseqüències a diferents nivells (individual,. poblacional, específic i fins i tot ecosistèmic). La força impulsora del moviment més predominant i generalitzada és distribució dels recursos en el medi, important tant a gran escala (moviments migratoris) com en els moviments diaris de recerca d’aliment a escala petita. En les aus marines en particular, el moviment té repercussions profundes en les seves característiques morfològiques i de comportament, en la seva història de vida, i la seva història evolutiva. El desenvolupament de dispositius de seguiment més petits, barats i precisos ha promocionat la proliferació d’estudis del moviment animal des d’un punt de vista multi- colònia, de població i fins i tot d’espècie. En aquesta tesi, desenvolupo diferents funcions per testar els biaixos introduïts en l’estudi del moviment, a través de dades de seguiment individual, a nivell de població o espècie. Posteriorment, utilitzo aquestes eines per a analitzar la connectivitat migratòria i la segregació dels hàbitats d’hivernada, des d’un punt de vista multi-colònia, de les baldrigues cendroses de l’Atlàntic (Calonectris borealis), del Mediterrani (C. diomedea), i de Cap Verd (C. edwardsii). Per últim, aplico un mètode innovador de modelatge espacial per a estudiar les distribucions d’alimentació de baldrigues cendroses de l’Atlàntic criant en tres colònies veïnes, per detectar-ne la segregació i descobrir-ne les causes, tant ambientals com comportamentals, incloent com els diferents mecanismes de transferència d’informació entre individus poden afectar a aquestes distribucions. Els resultats d’aquesta tesi tenen rellevància per a la ecologia del moviment en general, ja que són aplicables a dades de moviment individual de qualsevol espècie, independentment de l’aparell de seguiment utilitzat, i en el camp de l’ecologia de les aus marines, ja que proporciona nous coneixements sobre els diferents factors afectant la distribució i l’ús de l’espai, tant durant la cria com durant la hivernada, en aus pelàgiques.
Bjorkland, Rhema Hyacinth. "An Assessment of Sea Turtle, Marine Mammal and Seabird Bycatch in the Wider Caribbean Region." Diss., 2011. http://hdl.handle.net/10161/5632.
Повний текст джерелаSea turtles, marine mammals and sea birds are vulnerable to higher mortality rates as a direct function of incidental capture (bycatch) in marine fisheries. Their migratory behavior exposes them to multiple fishing gear types and fishing practices and efforts to understand the rates of interaction between these taxa and fishing necessarily entails analysis of data over large spatial areas (ocean-basin) and multiple types of fishing activities. The acquisition the requisite data, however, requires considerable resources and many regions in the world are data-poor with respect to bycatch, including the Wider Caribbean Region (WCR) in the west central Atlantic Ocean basin. This dissertation presents the results of multiple strategies used to assess sea turtle, marine mammal and seabird bycatch in the WCR, with a particular focus on sea turtle bycatch. The research incorporated a synthetic review of the literature, expert consultation, statistical techniques, and geospatial analyses to assess the bycatch seascape for the region. I conclude that sea turtle bycatch in the WRC is significantly linked to turtle rookeries, especially those on the continental land mass and in the southern section of the Caribbean basin, in large part because of the near shore artisanal nature of the fisheries and the importance of these habitats for foraging and reproduction. The limited information on marine mammal bycatch does not permit robust inferences, but it clearly identifies threats to at least one vulnerable marine mammal species, the tucuxi (Sotalia fluviatilis). Information on seabird bycatch was even more limited; the most vulnerable seabird populations occur in the higher latitudes (temperate zones) while the seabird populations in the WCR face significant threats from habitat loss and over-exploitation. This dissertation proposes specific recommendations for improving and advancing the information base for a regional, ecosystem-level management and mitigation of bycatch.
Dissertation
Wallace, Sarah. "Testing the role of Baja California generating biodiversity: A test case characterizing the population genetic structure of Cassin's auklet (Ptychoramphus aleuticus)." Thesis, 2012. http://hdl.handle.net/1974/7556.
Повний текст джерелаThesis (Master, Biology) -- Queen's University, 2012-09-28 14:02:24.007
Lamb, Juliet S. "Managing Vegetation to Restore Tern Nesting Habitat in the Gulf of Maine." 2011. https://scholarworks.umass.edu/theses/623.
Повний текст джерелаSpencer, Sarah M. "Diving Behavior and Identification of Sex of Breeding Atlantic Puffins (Fratercula arctica), and Nest-Site Characteristics of Alcids on Petit Manan Island, Maine." 2012. https://scholarworks.umass.edu/theses/812.
Повний текст джерелаRonconi, Robert Alfredo. "Patterns and processes of marine habitat selection: foraging ecology, competition and coexistence among coastal seabirds." Thesis, 2008. http://hdl.handle.net/1828/941.
Повний текст джерелаPattison, Vivian. "A hidden Markov modelling approach to understanding Ancient Murrelet behaviour and foraging habitat." Thesis, 2020. http://hdl.handle.net/1828/11698.
Повний текст джерелаGraduate
2021-04-17