Seabirds are wide-ranging apex-predators and useful bio-indicators of marine systems. Nevertheless, changes are occurring in the marine environment, and seabirds require protection from the deleterious effects of climate change, fisheries, pollution, offshore development, introduced predators and invasive species. The UK supports internationally important populations of seabirds but also has vast wind and wave resources, therefore understanding how seabirds use the marine environment is vital in order to quantify the potential consequences of further exploiting these resources. In this thesis I first describe the range of wave energy converting devices operational or in development in the UK, and review the potential threats and benefits these developments may have for marine birds. I then synthesise data from colony-based surveys with detailed information on population dynamics, foraging ecology and near-colony behaviour, to develop a projection model that identifies important at-sea areas for breeding seabirds. These models show a positive spatial correlation with one of the most intensive at-sea seabird survey datasets, and provide qualitatively similar findings to existing tracking data. This approach has the potential to identify overlap with offshore energy developments, and could be developed to suit a range of species or whole communities and provide a theoretical framework for the study of factors such as colony size regulation. The non-breeding period is a key element of the annual cycle of seabirds and conditions experienced during one season may carry-over to influence the next. Understanding behaviour throughout the annual cycle has implications for both ecological theory and conservation. Bio-logging can provide detailed information on movements away from breeding colonies, and the analysis of stable isotope ratios in body tissues can provide information on foraging during the non-breeding period. I combine these two approaches to describe the migration strategies of northern gannets Morus bassanus breeding at two colonies in the north-west Atlantic, revealing a high degree of both winter site fidelity and dietary consistency between years. These migratory strategies also have carry-over effects with consequences for both body condition and timing of arrival on the breeding grounds. Finally, I investigate the threats posed to seabirds and other marine predators during the non-breeding period by collating information on the distributions of five different species of apex predator wintering in the Northwest African upwelling region. I describe the threat of over-fishing and fisheries bycatch to marine vertebrates in this region, and highlight the need for pelagic marine protected areas to adequately protect migratory animals throughout the annual cycle. In summary, the combination of colony-based studies, bio-logging, stable isotope analysis and modelling techniques can provide a comprehensive understanding of the interactions between individuals and the marine environment over multiple spatial and temporal scales.

As ectothermic marine megafauna, sea turtle physiology and ecology are tightly intertwined with temperature, seasonality, and oceanography. Identifying how turtles respond when exposed to cold water, how they adapt to cold environments when they need to explore cold environments in order to forage, and what foraging resources are exploited by sea turtles are all components central to their conservation. Cold-stunning is a well-documented phenomenon that occurs when water induced decreases in sea turtle body temperature cause turtles to become immobilized and wash ashore. While most cold-stunned turtles are rescued and rehabilitated, we do not know whether cold-stunning is an acute transient occurrence, or a symptom of a bigger environmental problem. Further, while in some environments avoiding cold water is preferential, in other habitats, sea turtles need to inhabit cold environments in order to forage. Along the Eastern Pacific Rim, discrete upwelling locations are characterized by high primary productivity and unusually cold water. In these environments, avoidance is not possible and sea turtles require physiological adaptions to mitigate body temperature decreases in cold water. Little is known about how turtles handle upwelling environments, despite the fact that sea turtles remain in these habitats regardless of water temperature fluctuations. Because upwelling habitats provide increased nutrient presence, and sea turtles are opportunistic foragers, quantification of diet composition will further our understanding of why sea turtles remain in cold water environments year-round. Diet composition in multiple populations of cohabitating sea turtles revealed partitioning that results in reduced inter-specific competition. Further, flexibility in diets provides a wide range of ecosystem services central to habitat resiliency. Therefore, conservation of endangered sea turtles requires complete ecosystem conservation, and complete understanding of the interconnectivity of sea turtles and their environments is crucial.<br>

The aim of this paper is to use isotope analysis of carbon, nitrogen and sulphur from bone and teeth to investigate whether women from the Viking age and early medieval cemetery in Varnhem were local, rather than from a wider area. What is interesting about this area is that it is a Christian cemetery that was taken into use as early as the Viking age (800-1050 AD), a time where the majority of the Swedish population were pagans. It is therefore thought that the majority of the people buried on the cemetery are people from other parts of the landscape, since few other Christian cemeteries are known from his time. I tested my hypothesis with two research questions regarding diet and sulphur isotope ratios. The results from the isotope analysis showed that the women had a rather homogeneous diet and homogeneous sulphur isotope values. These results can strengthen my hypothesis that they were resident in Varnhem.

The discovery of two mass graves in England in 2010 containing the remains of Scandinavian men in their prime from the Viking age against the historical backdrop of Anglo-Saxon England has elicited questions as to whether or not they were victims of ethnic cleansing. Literature studies combined with the results from the post-excavation analyses render the conclusion that the victims in the grave, most likely, were not subjected to ethnic cleansing. It is more plausible that they were Scandinavian mercenaries who were executed during an intense period where a failing England was desperately paying for its own conquest with the Danegeld. The historical documents give the impression that a nation-wide genocide against Danes took place, however the archaeological material and analyses do not fully support this scenario. / Mot bakgrunden av den anglosaxiska perioden i England har upptäckten 2010 i England av två massgravar innehållande kvarlevor av vikingatida skandinaviska män väckt frågor om huruvida offren var utsatta för etnisk rensning. Resultat från analyser av materialet från utgrävningarna i kombination med litteraturstudier leder till slutsatsen att individerna i graven sannolikt inte var offer för etnisk rensning. Det förefaller mer troligt att männen var legosoldater vilka avrättades under den intensiva period då det skuldtyngda England betalade stora summor danagäld till vikingarna. I de historiska källorna beskrivs hur massmord av daner ägde rum över hela landet, dock finns det inget i det arkeologiska materialet eller i analysresultaten som stöder en sådan händelseutveckling.

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I investigated if constructed wetlands provide breeding habitat for the Horned Grebe (Podiceps auritus) in northwest Alberta. Over two years, I conducted bird surveys of 201 borrow-pits (ponds created during road construction) and 18 natural wetlands and collected data on local habitat and landscape features. For subsets of ponds, I also collected water chemistry and invertebrate data, and conducted stable isotope analysis. Grebes occurred on 36% of borrow-pits and produced chicks on 61% of occupied sites in 2007 and 81% in 2008. Grebes occurred more frequently on larger ponds, with more emergent vegetation, and avoided forested ponds that supported beaver activity. Horned Grebes are generalist foragers that did not select nesting ponds based on food-web structure. Twenty-six other bird species used borrow-pits, with distinct assemblages occurring on agricultural versus forested ponds. My study indicates that wetland construction offers a viable method for creating habitat for Horned Grebes and other species. / Ecology

An archaeozoological analysis of the assemblages of animal bones and teeth of Neolithic (Linear and Stroked Pottery cultures; approx. 5500-4200 BC)settlements in Bohemia, provide new elements on the way of life of early farmers. By means of study of animal bones and teeth we can specify the role of domestic and hunting animals in the Neolithic economy, define the herd management strategies for main domestic animals and focus on the environmental reconstruction and investigation of births distribution of domestic animals (for exemple of cattle in the case of this study) through the analysis of the carbon and oxygen isotopic compositions of fossil tooth enamel bioapatite. To achieve these objectives, we can use, except standard archaeozoological methods and stable isotope analysis, more specific procedures, e.g. determination of damaged bones of animals using the ELISA test.

Most albatrosses are critically endangered, endangered or vulnerable due to the deleterious impact of fisheries, pollution, introduced species, habitat alteration, and climate change. Foraging behaviour influences many aspects of seabird biology, and a detailed understanding of foraging ecology is required to better predict the impacts of significant changes to the marine environment. Campbell Albatross (Thalassarche impavida) is a threatened endemic, confined to a small number of locations on Campbell Island, New Zealand and was recently split from the closely related Black-browed Albatross (T. melanophrys). We currently lack much basic information on the foraging behaviour of this species, hindering our ability to understand how change may have occurred in the past and make predictions about it’s long-term future. First, I used GPS loggers and stable isotope analysis of blood to investigate how distribution and foraging effort (distance travelled and duration) varied with sex and breeding stage. I found that Campbell Albatrosses are sexually dimorphic and showed sex-specific foraging behaviour and habitat use – although this varied by stage of reproduction. Because males and females may be vulnerable to different threats, such as interactions with fisheries, I compared the spatial overlap and high resolution spatio-temporal overlaps between fisheries vessels and albatrosses within New Zealand’s Exclusive Economic Zone (EEZ). Albatrosses utilised 32% of the EEZ, however they overlapped with fisheries vessels in only 0.20% of the area. Previous research has demonstrated that the influence of fisheries vessels goes beyond the immediate location of the boat itself. Campbell Albatross have low levels of spatio-temporal overlap with fisheries – with males overlapping more than females. More generally, my results indicate that adding data on fine scale interactions will improve fisheries risk assessments, and provide information needed for the conservation and management of the Campbell Albatross. A key development in recent ecological research has been a greater appreciation that inter-individual variation in foraging behaviour can have profound population-level consequences. Accordingly I tested for individual differences in foraging behaviour in Campbell Albatrosses. The majority of individuals demonstrated both annual and inter-annual individual consistency in foraging locations, and the degree of specialisation was influenced by both sex and year. Consistent terminal latitude and longitude of foraging trips indicated high foraging area fidelity with a degree of flexibility in the fine-scale location. During brooding, females used the Campbell Plateau and showed more consistent behaviours than males, which tended to forage in the Southern Ocean. This adds to a growing body of evidence of individual foraging specialisation among seabirds in general and albatrosses in particular and reveals marked inter-individual differences in vulnerability to threats. In light of the evidence of individual foraging specialisations in the Campbell albatross, I also preformed a literature review of individual foraging specialisations across all seabirds. I found studies examining foraging specialisation for 35 species, with 28 (80%) providing evidence of consistent inter-individual differences (i.e. specialisation). Current studies suggest that specialisation is influenced by environmental variability and resource predictability, however, with limited data in tropical regions, more studies are needed to test these links. In summary, my thesis has provided new information on Campbell Albatross foraging ecology. Sex specific variations in behaviour and habitat use may influence conservation and management strategies. I have been able to contextualise the consistent individual differences in foraging distribution described for this species in light of global patterns of individual foraging specialisation in seabirds and highlight future areas of research.

Large, mesopelagic teleosts have a potentially keystone position in the ecology of the pelagic water column, yet remain relatively unstudied when compared to large, commercially important fishes of the epipelagic zone. In this study, the ecological roles of four large, vertically migrating teleosts, oilfish, Ruvettus pretiosus, escolar, Lepidocybium flavobrunneum, snake mackerel, Gempylus serpens, longnose lancetfish, Alepisaurus ferox, and shortnose lancetfish, Alepisaurus brevirostris, were examined. The stomachs of 61 oilfish, 35 escolar, 33 snake mackerel, and 34 lancetfish were collected from nighttime, pelagic, longline fishing operations in the epipelagic zone of the western North Atlantic Ocean and Gulf of Mexico from 2007 to 2010. Stomach content analysis was used to determine predator-prey interactions. Stable carbon and nitrogen isotope analyses were performed on white dorsal muscle tissue of 38 oilfish, 23 escolar, 28 snake mackerel, and 19 lancetfish also sampled for stomach content analysis. Crustaceans were abundant prey of small oilfish, lancetfish, and to a lesser degree, snake mackerel, and they were absent from large escolar diets. Lancetfish and snake mackerel showed diverse diets that included crustaceans, polychaetes, gymnosomes, salps, cephalopods, and fishes. Large escolar stomachs contained only squid and fish. Stable isotope analyses placed small oilfish in the lowest trophic position of the group, followed by lancetfish and snake mackerel, and large escolar occupied the highest trophic position of the four species.

Stable isotope ratios in rainwater and water vapor act as a tracers of the hydrological cycle. The data on stable isotopic composition in rainwater and water vapor are limited due to the lack of observational studies across the Indian subcontinent and over the ocean. These present day observations are important database to deduce the paleo-climatic condition from geological archives. In majority of the cases, isotopic records are translated into physical factors with the present background knowledge where relationships with physical variables are well established. In case of tropical region, the primary controlling factor identified behind the stable isotopic variations is the amount of rainfall. However recent observations contradict such relationships challenging the role of amount effect and identified source moisture effect on stable isotope ratios in rainwater at Indian stations. The thesis investigated the amount effect relationship of isotopes at seasonal time scales. The long period observation covering 4 years, where daily time interval rainwater samples collected were used for our study. We used two different station locations; Thiruvananthapuram and Bangalore, where monsoonal rainfall is received for Southwest and Northeast periods. The role of mesoscale and synoptic convection and rainout along the transport pathways were found responsible for the isotopic variance. The role of moisture source regions, rainout over the advection pathways, high rainfall producing systems such as depression and cyclones, and continental recycling of water on rainwater and water isotopes ratios were major findings of the thesis work which are detailed in the chapters. Upon knowing the atmospheric and oceanic condition at the moisture source region based on satellite data and reanalysis data set we modeled our observations using the governing equations of isotope fractionation and well accepted Rayliegh’s distillation model. The observations on rainwater and water vapor isotope ratios in oceanic region are extremely limited due to difficulties in conducting sampling. Water vapor and rainwater observations over the Southern Ocean during the expedition of 2013 and estimation of the moisture recycling across the latitudes over the oceanic regions is a novel work in this thesis.