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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Cultural and ecological relationships among consumers, food, and landscapes; implications for stewarding bear-human-salmon systems

Adams, Megan Sara 02 May 2019 (has links)
Human activity modifies the behaviour of large vertebrates and their acquisition of key resources. Despite the predation risk and competition for similar food resources that humans impose, wildlife consumers must acquire key foods across the landscape. Predation risk can modify foraging behaviour, yet we know little about the potential consequences, especially on large spatial scales. Humans may also affect food availability for wildlife by competing for shared prey, which most current harvest prescriptions fail to recognize. Against this background of threats to consumer-resource interactions, my research employed new conceptual, analytical, and practical approaches to seek not only new generalizable insight but also applied solutions. Addressing these goals, I characterized foraging behaviour by grizzly bears (Ursus arctos horribilis) on a focal prey, Pacific salmon (Oncorhynchus spp.), at multiple spatial scales. I predicted how human activity – both as modifications to landscapes and as salmon harvest – might affect bear-salmon interactions. I co-conceived, designed, and carried out this work through a framework of community engagement, which I crafted in collaboration with Indigenous communities in coastal British Columbia (BC). The framework (Chapter 2) identifies how scientists and communities can engage throughout the research process to work towards shared priorities, despite potential challenges in differences of knowledge systems or capacities. Methodologically, I used ratios of stable carbon (δ13C) and nitrogen (δ15N) isotopes in bear hair to estimate relative contributions of salmon in the annual diet of bears and employed existing data on landscape modification and salmon fisheries (i.e., escapement and catch) to characterize human activity and to measure associated variation in salmon consumption by bears. My first empirical contribution (Chapter 3) characterized spatial patterns of annual salmon consumption by grizzly bears across BC. I found substantial differences in salmon consumption within and among grizzly and black (U. americanus) bears in a large coastal region and across BC. Visualizing variation in consumer-resource interactions could guide conservation and management efforts that seek to protect predator-prey associations and marine subsidies for terrestrial ecosystems. I also investigated potential drivers of salmon consumption by bears in interior and coastal watersheds that varied in disturbance (Chapter 4). I found that human footprint in riparian areas of salmon-bearing watersheds affected bear diets more than the amount of salmon biomass available, showing that human activity can disrupt an otherwise strong predator-prey association. My community-based research occurred at the scale of a single large watershed, where I demonstrated how the Wuikinuxv First Nation might design their salmon management prescriptions according to their cultural values (Chapter 5). Despite a reduced abundance of salmon in the area, I identified harvest options that would trade-off benefits to local people and bears equally. In general, my dissertation research contributes to our understanding of the role humans increasingly play in mediating consumer-resource interactions. I also highlight how scientific research can support the leadership that local management can provide in mitigating human impacts to sustain an iconic predator-prey interaction of ecological, economic, and cultural importance. / Graduate / 2020-04-23
52

Understanding conservation conflicts surrounding predation and game shooting interests

Swan, George Julius Fraser January 2017 (has links)
Many predatory species cause negative impacts on human interests by threatening game, livestock or human safety. These impacts can create conflicts where stakeholders differ over wildlife management and when one party is perceived to exert their interests at the expense of the other. Finding effective methods to mitigate conservation conflicts requires an interdisciplinary perspective that investigates (i) the reality of the apparent impacts, (ii) the efficacy of any methods intended to remedy them and (iii) the perceptions, motivations and objectives of key stakeholders. In this thesis, I investigated a conservation conflict in the U.K. surrounding predators and game management. I did so with specific reference to the common buzzard Buteo buteo, a species that, due to predation of released pheasants Phasianus colchicus, is both subject to illegal persecution and on- going controversy concerning the licenced selective removal of ‘problem individuals’. I first review the literature to assess the ecological evidence that certain ‘problem individuals’ can be both disproportionately responsible in impacts upon human interests and more likely to reoffend. I show that while there is evidence for these animals across many different taxa, the benefits of their removal can sometimes be short-lived. I highlight possible indirect impacts of selective management and identify it as a potential compromise between different stakeholder groups. Next, I evaluate the performance of Bayesian stable isotope mixing models (BSIMMs) in quantifying the diets of wild animals. By comparing indirect and direct observations of buzzard foraging, I demonstrate that, with the correct selection of trophic discrimination factors, stable isotope analyses can provide a reliable picture of dietary composition that mirrors direct observations. I then apply these mixing models to evaluate the ecological basis of selective removal of ‘problem buzzards’. The results suggest that the consumption by buzzards of released pheasants is not limited to release pens where gamekeepers perceive buzzard predation to be a problem. However, I then show that stable isotope analysis of blood sampled from two of the four buzzards caught inside pens indicates frequent consumption of released pheasants, relative to the rest of the buzzard population. These results suggest that, while some pheasant consumption may go undetected, selecting only buzzards inside pens for removal is likely to target ‘problem birds’. I then investigate buzzard foraging and breeding ecology on land managed for pheasant shooting. I find that buzzards nest at higher density in areas with greater abundances of pheasants and rabbits Oryctolagus cuniculus. However, records of provisioning from nest cameras showed that only rabbits were caught in proportion to their abundance and only rabbit provisioning rate was associated with buzzard productivity. I suggest that the positive relationship between buzzard and pheasant abundance, although seemingly unconnected to pheasant predation, might influence how gamekeepers perceive buzzard impact. Next, I conduct semi-structured interviews on the subject of predator control with 20 gamekeepers across the south of England, to explore the underlying beliefs, norms and information sources that motivate their behaviour. From these interviews, I identify a number of separate, but interconnected, motivations that influence predator control including professional norms, potential penalties, and interpretations of what is ‘natural’. The influences of these motivations are discussed in detail and a conceptual model, incorporating the theory of planned behaviour, is developed. Finally, the key contributions of this thesis are drawn together and discussed in their wider context. Taken together, the results of this thesis illustrate how predator management occurs simultaneously within social and ecological contexts that incorporate the individual attributes of both predators and people. The results of this thesis have direct implications for the management of predators, the representation of stakeholder perspectives and the design of conflict mitigation measures.
53

Application of δ13C, δ15N and δ34S for the reconstruction of diet and migration at Boğazköy, Central Anatolia

Caldeira, Claudia Filipa Nunes January 2017 (has links)
The patterns of human diet and migration of the population of Boğazköy in north-central Anatolia were investigated through the application of carbon (δ13C), nitrogen (δ15N) and sulphur (δ34S) stable isotope analysis of bone collagen. The materials used for this research include human and faunal bone samples dating from the Bronze Age to the Roman period. This is the first isotopic study conducted at Boğazköy and for these time periods in north-central Anatolia. The aim of the research was both to reconstruct the dietary habits and mobility patterns of this community as well as investigating the usefulness of δ34S analysis as a dietary tool in this region of Anatolia. Examining the diet and economy at Boğazköy through an isotopic perspective provides a clearer understanding of the life of the inhabitants of the city and sheds light of the political and sociological changes observed during this period in Anatolia. Analysis across different periods revealed that the Bronze Age stands out with the most enriched δ15N (9.9±0.8‰) and δ34S (12.6±3.0‰) values, suggesting a higher consumption of protein in relation to later periods and/or foreign origin for these individuals. With the exception of the Bronze Age, dietary behaviours were very similar across all phases of occupation and do not differ significantly from those observed at other Anatolian sites. The δ13C (‒18.6±0.4‰) and δ15N (9.0±0.9‰) average values for the Iron Age, Hellenistic and Roman periods suggested a diet predominantly based on C3 terrestrial sources. Variations between individuals, implying the consumption of different levels of animal protein, were not directly connected to sex or age. The δ13C results for several of the domestic animals suggest inclusion of C4 plants in their diets. Slight elevated δ13C values for humans indicates the consumption of these animals or the variability of C3 plant values, which may relate to the aridity of this region. The δ15N results suggest the consumption of low quantities of meat, dairy products and/or the contribution of pulses. The application of δ34S has also provided insight into Boğazköy’s economy by suggesting the use of transhumance as a herding strategy during the Iron Age. The presence of foreigners during the Hittite period is also implied by the δ34S results from the human samples. These indicate a coastal provenance where sea-spray effect was visible; however, the lack of a δ34S baseline data for large regions of Anatolia hinders further interpretation of the results.
54

Slaget vid Tollense : Professionella krigare i bronsålderns Nordeuropa / The battlefield of the Tollense : Professional warriors in Bronze Age Northern Europe

Reinhold, Linn January 2019 (has links)
Abstract 3200 years ago a massive battle took place at the river Tollense in MecklenburgVorpommern, Germany, possibly involving thousands of people. 130 victims have been found so far. Several show signs of former violence. Axes, wooden clubs, knives and a vast number of arrowheads have been found among the human skeletal remains. According to isotope analyses on tooth enamel from human remains at the site, a considerable amount of the victims did not originate from the local area. The isotope analyses divided the victims into two major groups, one local and the other probably originating from Central Europe. In other words, the battlefield of the Tollense were not fought by local farmers and craftsmen. This, together with the extent of the battle, the weapon finds and traumata on the human remains, has led archaeologists to assume that the battle was fought by professional warriors. If this is true, the battlefield of the Tollense would be the first of its kind in the Northern European Bronze Age. Sammanfattning Uppsatsen diskuterar omfattningen och karaktären av slaget vid floden Tollense som utspelade sig för 3200 år sedan i vad som idag är Nordtyskland. Slagfältet har uppmärksammats för att vara den första konflikten med professionella krigare i bronsålderns Nordeuropa. Tidigare forskning om ämnet saknar en konsekvent definition av begreppet professionell krigare. För att avgöra om det var professionella krigare som stred vid Tollense definierar uppsatsen begreppet utifrån teoretiska perspektiv såsom antropologiska klassifikationer av hövdingadömen, krigare och soldater, men också genom att belysa kontaktnätverken och den långväga handel som växte fram under bronsåldern. Omfattningen och karaktären av slaget vid Tollense beskrivs utifrån hur många människor som deltog på slagfältet samt vilka arkeologiska fynd som talar för huruvida de var professionella krigare och inte lokala bönder och hantverkare som drabbade samman. Uppsatsen är en klassisk litteraturstudie. Utgrävningarna vid Tollense pågår i skrivande stund, vilket innebär att det inte finns någon slutpublikation med färdigställda resultat. För att besvara frågeställningarna om antalet deltagare i konflikten samt huruvida de var professionella krigare eller inte, redogör uppsatsen för analyser av de mänskliga kvarlevorna som återfunnits vid Tollense och vapnen som användes på slagfältet. Avslutningsvis ger uppsatsen en personlig tolkning av vad fyndmaterialet säger om hur många människor som var involverade i konflikten och vad som talar för att de var professionella krigare. Diskussionen lyfter fram hövdingadömen som centraliserade och hierarkiska samhällsstrukturer och hur detta möjliggör organiserad krigföring.
55

Marked in life and death: identifying biological markers of social differentiation in late prehistoric Portugal

Waterman, Anna Joy 01 May 2012 (has links)
This dissertation research is a bioarchaeological investigation of Late Neolithic through Early Bronze Age (3600-1800 BC) burial populations from the Portuguese Estremadura. In this project macroscopic and isotopic analyses of skeletal and dental materials are used to gather information pertaining to diet, health status, and inter-lifetime mobility patterns for individuals interred at different burials within a small geographic area with the goal of evaluating the level of social differentiation in the region. The archaeological record for the transition between the Late Neolithic and the Early Bronze Age in southwestern Portugal demonstrates clear evidence of the rise of a socially-complex, non-state society. During the Early Bronze Age, however, this region underwent a period of social `devolution' which cumulated in widespread settlement abandonment. To date, it is unclear to what extent sociopolitical or environmental factors contributed to this social collapse. This study seeks to expand our knowledge of social differentiation in the Late Neolithic to Early Bronze Age of the Estremadura region of Portugal and provide insight into social structure during the emergence and collapse of early complex societies in Iberia. The results of this study found that there were statistically significant differences in dietary, mobility and demographic patterns between burials that suggest socially distinct populations were interred at different sites. In particular, one burial site, Cova da Moura, diverged significantly from the other sampled burial populations. However, based upon the data presented here, it was not possible to tie these biological markers of differentiation to particular aspects of Late Neolithic to Early Bronze Age social organization. Therefore, while this study successfully identified differences between burial populations, at this time, it is not possibly to relate these to particular hierarchical structures. It is suggested that aspects of burial practices in the region confound biologically-based investigations of social organization in a similar way that they have impeded researchers' abilities to identify elite versus non-elite individuals through grave goods alone. Nonetheless, despite these obstacles, this work provides strong evidence of population heterogeneity in the region, and has implications for our understanding of the evolution of complex societies in the Iberian Peninsula and elsewhere.
56

A MULTI-INDICATOR APPROACH TO UNDERSTANDING THE DIAGENESIS OF CARBONATES IN PENNSYLVANIAN MUDROCKS OF THE MIDLAND BASIN

Reis, Alex J. 01 January 2018 (has links)
The Late Pennsylvanian was a time of frequent, rapid glacioeustatic sea-level changes. These changes were recorded in the Wolfcamp D Formation of the Midland Basin as a series of cyclothems similar to those studied in the Midcontinent region (e.g., Algeo and Heckel, 2008). This study focuses on identifying the mechanisms and controls on carbonate deposition and diagenesis through the Upper Pennsylvanian Wolfcamp D Formation and evaluating the potential for these layers to be stratigraphically significant. A stepwise progression of diagenetic processes was identified through the use of δ13Ccarb and δ18Ocarb, bulk geochemical and petrographic analysis, and scanning electron microscopy. Carbonate deposition and early-burial diagenesis appears to be strongly influenced by frequent changes in sea-level and benthic redox conditions. The transition to deep-burial diagenesis was controlled by the thermal gradient in the basin and the extent of diagenesis by the amount of clays and organic matter in the surrounding mudrocks. Further diagenesis was induced through interactions with a brine following clay diagenesis. The presence of multiple phases of diagenesis in this system further highlights the need for several lines of inquiry when evaluating the post-depositional evolution of carbonates in a mud-rich setting.
57

A JOINT XRF-δ<sup>13</sup>C<sub>carb</sub> CHEMOSTRATIGRAPHIC APPROACH FOR CHARACTERIZING PALEO-ENVIRONMENTAL PROCESSES IN THE MUDSTONE-DOMINATED WOLFCAMP FORMATION OF WEST TEXAS

Tamakloe, Frank 01 January 2019 (has links)
The Late Paleozoic Ice Age represents a dynamic period in Earth system history recording a shift from icehouse to greenhouse conditions. Concomitant with this change was a series high-frequency, high-amplitude sea level fluctuations leading to the deposition of “Kansas type” cyclothems in the Mid-Continent, and a similar rhythmic expression of interbedded shales and carbonates in the Midland Basin. Stable isotope geochemistry is a particularly powerful tool when examining these mud-rich successions because changes in organic matter partitioning may be recorded first in δ13CDIC of sea-water and consequently in δ13Ccarb of marine rocks. The δ13Ccarb record may also illuminate early and late-stage diagenetic processes and associated destruction of organic matter. This study used high-resolution x-ray fluorescence (XRF) and δ13Ccarb measurements to analyze paleo-environmental conditions in two cores within the Midland Basin Wolfcamp Formation. Using this approach, the combination of more positive δ13Ccarb measurements and enrichment of redox-sensitive elements reflect conditions more favorable for organic matter enrichment in the distal core. Additionally, four (< 6 in.) early-diagenetic intervals have been identified representing prolonged periods of reduced or non-deposition based on sharp negative δ13Ccarb excursions. These horizons are proposed as potential chronostratigraphic tie-points between the two core localities.
58

Stable carbon isotope ratio of polycyclic aromatic hydrocarbons (PAHs) in the environment: validation of isolation and stable carbon isotope analysis methods

Kim, Moon Koo 15 November 2004 (has links)
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous, toxic contaminants that are released to the environment from various petrogenic and pyrogenic sources. In an effort to more clearly identify and trace sources of PAHs in the environment, purification and compound specific isotope analysis methods were developed to accurately measure the stable carbon isotope ratio of individual PAHs. Development of the method included improving accuracy and precision of the isotopic measurement by producing highly pure extracts using various chromatographic techniques. The method was refined by improving compound separations using purification techniques and high resolution chromatographic columns. The purification method consists of alumina/silica gel column chromatography, gel permeation chromatography and thin layer chromatography. The mean recovery of PAHs after the purification procedure was approximately 80 %. Sample purities after purification were verified by GC/FID and full scan mass spectrometry. To better resolve peaks and provide more accurate stable carbon isotope measurements, various gas chromatographic conditions were evaluated. The precision of the method ranged between 0.08 and 0.43 . The analytical protocols were evaluated to confirm compositional and stable isotopic integrity during purification and stable isotopic analysis. To confirm the utility of the purification and isotope analysis methods, various environmental samples from marine, land and lacustrine environments were analyzed. The isolates were analyzed for the composition and the stable carbon isotope ratios of PAHs. The stable carbon isotope ratio was measured by GC/IRMS and the results, along with quantitative compound compositions, were used to characterize and identify the contaminant sources. The sources of the PAHs in the study areas were differentiated by PAH molecular ratios and confirmed by stable carbon isotope ratios. This study confirms that compound specific isotope analysis of pollutants by GC/IRMS can be used to identify PAH sources in environmental samples. The study also confirms that the purification and stable carbon isotope analysis methods that were developed can be used to accurately measure the stable carbon isotope ratios of PAHs in environmental samples for the purpose of source identification. GC/IRMS measurement of stable isotopic compositions can be an effective fingerprinting method when used in conjunction with traditional molecular composition methods.
59

Role of landscape composition and geographical location on breeding philopatry in grassland passerines : a stable isotope approach

Brewster, Katherine Rose 01 April 2009
Grassland bird populations in North America are in steady decline. Despite declining faster and more consistently than any other group of birds, grassland songbird populations are relatively understudied and little is known about factors driving breeding-site philopatry and dispersal. Landscape and habitat composition may influence fidelity of grassland songbirds to a breeding area. As predicted by the theory of the <i>Ideal Free Distribution</i>, high-quality sites are likely to have a higher percentage of return breeders than low-quality sites because higher quality sites should have more or better-quality resources birds need for improved fitness. Using stable hydrogen isotope (äD) analysis, I approximated minimum fidelity rates of two grassland songbirds to two landscape (grass- vs crop-dominated landscapes) and two habitat (native grass vs planted grass) types. I hypothesized that grassland songbirds would return more readily to higher quality sites. For Spragues Pipit (<i>Anthus spragueii</i>), a habitat specialist, this would mean returning more readily to native grass habitat in grass dominated landscapes. I expected no difference in return rate of Savannah Sparrow (<i>Passerculus sandwichensis</i>), a habitat generalist, to either habitat or landscape. However, I found that the proportion of non-returning breeders was not influenced by landscape or habitat for either species. Furthermore, I examined attributes (distance from capture point to nearest crop and to the nearest road, as well as the percentage of native grass, planted grass, water and woody vegetation within landscape and territory buffers around the capture point) of the landscape and territory of each individual to determine if specific landscape or territory characteristics influenced their return rate to a breeding area. Neither species showed an affinity or aversion to any of the landscape or territory characteristics considered.<p> At a larger scale, geographical position within the breeding range may influence dispersal rates of migratory songbirds. Given that environmental factors often change in a clinal manner, central populations presumably experience the most favorable environmental conditions and peripheral populations the least favorable. Therefore, geographically peripheral locations likely occur in ecologically marginal or stressful conditions, resulting in higher dispersal rates of migratory birds. I examined the differences in dispersal rates of two grassland songbirds at two geographically distinct locations; one centrally located in the Spragues Pipit breeding range (Last Mountain Lake area, SK, Canada) and one at the periphery (Bowdoin National Wildlife Refuge, MT, USA). As expected, Spragues Pipits at the Bowdoin National Wildlife Refuge had a significantly larger dispersal rate than at the Last Mountain Lake area. Savannah Sparrow dispersal rates did not differ between locations at the more conservative outlier classification. These results provide some limited evidence that geographical position within the breeding range can influence dispersal rates.<p> Using äD analysis, I found that local amount-weighted growing-season deuterium in precipitation (äDp) at locations within grassland ecosystems differed from those long-term (45+ year) models described by stable hydrogen isotope ratio basemaps, illustrated in Hobson and Wassenaar (1997), Meehan et al. (2004) and Bowen et al. (2005). Therefore, I describe how äDp values were corrected from the long-term isoscape value predicted by Bowen et al. (2005). This method of determining year-specific local weighted growing-season äDp is an improvement upon the currently used Bowen et al. (2005) isoscape that is based on long-term precipitation patterns. To improve assignment of individuals to origins based on their äDf values, future research should incorporate year-to-year variation by applying year-specific corrections to the Bowen et al. (2005) isoscape.<p> More research is needed to determine the factors affecting the philopatry and dispersal of grassland songbirds in order to conserve them.
60

The Observed Stable Carbon Isotope Fractionation Effects of a Chloroform and 1,1,1-Trichloroethane Dechlorinating Culture

Chan, Calvin 21 November 2012 (has links)
Little is known about the enzyme-substrate interactions occurring during the dechlorination of chloroform (CF) and 1,1,1-trichloroethane (1,1,1-TCA) by the enrichment culture containing Dehalobacters, hereafter called DHB-CF/MEL. Compound specific isotope analysis (CSIA) is used to investigate the factors which may affect the isotope fractionation observed for CF and 1,1,1-TCA dechlorination. This thesis reports the first isotope enrichment factors observed for CF biodegradation at -27.5‰ ± 0.9‰, thus providing fundamental information for comparing isotope enrichment factors observed during trichlorinated alkane degradation by DHB-CF/MEL. The thesis also reports how the presence of CF and 1,1,1-TCA influences isotope fractionation and explores the possible influence of substrate inhibition on isotope fractionation during 1,1,1-TCA dechlorination. The data suggests that substrate inhibition during 1,1,1-TCA dechlorination by DHB-CF/MEL may not affect carbon isotope fractionation. The results suggest that CSIA is a promising monitoring tool even for the simultaneous biodegradation of CF and 1,1,1-TCA at different 1,1,1-TCA starting concentration.

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