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Food web structure is of underlying importance to ecological functions and processes. Whilst it is understood that a range of biotic and abiotic factors affect structure, relatively little is known of the role of biodiversity per se in structuring food webs. In this thesis I utilise novel multi-dimensional estimates of food web structure based on stable isotope ratios of nitrogen (δ15N) and carbon (δ13C) to quantify structural responses to changing community diversity. I additionally investigate methodological aspects of sample preparation and stable isotope quantifications of food chains. Using an arthropod prey-predator system, in chapter 2 I demonstrate that tissue selection and lipid extraction are important methodological procedures for deriving accurate δ15N and δ13C signatures. In chapter 3 I test the utility of δ15N to quantify food chain length, and δ13C to trace primary energy sources through to end consumers. Bayesian resampling of variance in sample means for plant and arthropod food chains produces robust isotopic estimates that match known food chain length well despite some error variance, and estimates of δ13C-range that trace trophic transfers. Chapter 4 represents a change in system from lab to field as I determine δ15N and δ13C signatures for plant and invertebrate species within three grassland communities representing a gradient of biodiversity. Quantifications of community bivariate isotopic space using isotopic metrics revealed that greater taxonomic richness increased both diversity of resource space exploited and overlap in resource space. These results therefore suggest that loss of diversity affected structure through altering relative patterns of niche partitioning in resource exploitation amongst community members. In chapter 5, I additionally find evidence that grassland management mediated changes in food web compartmental structure that were associated with differences in generalist invertebrate predator feeding habits. Taken together, these findings develop and demonstrate the utility of isotopic approaches to quantifying food web structure, and provide evidence of important mechanisms by which biodiversity affects food web structure. I conclude that the preservation of natural food web structure and trophic dynamics are further reasons for halting loss of biodiversity.

Submitted by JOSIANE SANTOS DE OLIVEIRA (josianeso) on 2017-09-27T16:50:50Z No. of bitstreams: 1 Arlete Redivo_.pdf: 939388 bytes, checksum: b53b1332885d62fa713b6beafc4afd85 (MD5) / Made available in DSpace on 2017-09-27T16:50:50Z (GMT). No. of bitstreams: 1 Arlete Redivo_.pdf: 939388 bytes, checksum: b53b1332885d62fa713b6beafc4afd85 (MD5) Previous issue date: 2017-06-28 / Nenhuma / O estudo procurou compreender a adoção e a implementação de padrões de produção sustentável na cadeia agroalimentar da soja na região amazônica. As bases teóricas que nortearam a pesquisa foram: Teoria dos Custos de Transação, Visão Baseada em Recursos e Teoria da Troca Social com o propósito de entender como ocorrem as relações contratuais e relacionais para adotar padrões de produção sustentáveis. A abordagem de pesquisa utilizada foi qualitativa, por meio de um estudo de caso. A coleta dos dados ocorreu por intermédio do sistema chamado bola de neve, com um roteiro de questionário semiestruturado, por intermédio do qual foram entrevistados os responsáveis das empresas processadora, certificadora, SEMA, Aprosoja, ICV, CAT, UFMT, EMBRAPA e um grupo de nove produtores de soja pertencentes ao CAT, que atuam na região amazônica, os quais adotam padrões de produção sustentável. A apreciação desses dados ocorreu por meio da técnica da análise de conteúdo cujos resultados apontam que a adoção e a implementação de padrões estão ocorrendo para atender a necessidade do mercado externo. As informações referentes à cadeia agroalimentar da soja permitem contribuir para a validação da teoria da cadeia de suprimentos, a qual, para o modelo estudado, é coordenada por entidades de apoio, com o propósito de integrar os elos da cadeia de suprimentos com o mercado externo. O uso das teorias junto à cadeia agroalimentar da soja à adoção de padrões de produção sustentáveis permitiu descobrir que a governança contratual e relacional que existe entre os elos envolvidos objetiva normatizar, direcionar, incentivar e facilitar práticas menos agressivas ao ambiente. Entre os produtores, para o caso estudado, constatou-se que as teorias complementam-se. Ao finalizar este estudo, conclui-se que esta pesquisa contribui para comprovar que, na região amazônica, existem produtores preocupados em demonstrar que se valem de formatos ambiental e socialmente corretos. Novos estudos, porém, são necessários no sentido de comparar se a governança contratual e relacional está presente em outros modelos de adoção de padrões, bem como, descobrir quais são os principais conflitos e dificuldades encontradas pelos produtores à implementação de padrões de produção sustentável. / This study aimed to understand the adoption and the employment of patterns of sustainable production in the agri-food chain of soybean in the Amazon region. The theoretical guidelines for the research were: Transaction Cost Theory, Resource-Based View and Social Exchange Theory. The objective was to understand how contract and relational connections take place for the adoption of patterns of sustainable production. The research approach used was qualitative with a case study. Data was collected through the Snowball Sampling Technique, with a semi-structured questionnaire script, which was used to interview those in charge of the processing and certifying companies, SEMA, Aprosoja, ICV, CAT, UFMT, EMBRAPA and a group of nine soybean producers associated to CAT who work in the Amazon region and adopt patterns of sustainable production. Data was evaluated through the Content Analysis Technique, whose results suggest that the adoption and employment of patterns are taking place to meet the necessities of the external market. The information related to the soybean agri-food chain contributes to the validation of the supply-chain theory, which, for the model studied, is coordinated by support entities aiming to integrate the supply chain and external market connection. The use of these theories in the soybean agri-food chain and the adoption of patterns of sustainable production allowed to determine that the contract and relational governance existing among the links involved has the objective of standardizing, guiding, encouraging and easing practices which are less aggressive to the environment. For the case studied, among the producers it was concluded that the theories complement each other. With the study finished, it is possible to realize that this research helps prove that, in the Amazon region, there are producers concerned in showing they use correct environmental and social formats. However, new studies are necessary to compare if the contract and relational governance is present in other models of pattern adoption, as well as to discover which are the main conflicts and difficulties faced by the producers to employ patterns of sustainable production.

ABSTRACT Aim: From its inception to its expansion nationally and internationally, the management of a restaurant franchise concept uses various critical success factors to overcome the barriers that they encounter throughout their different growth phases. This study aims to find out what the CSFs are for Swedish restaurant franchisors of different sizes, what barriers they encounter and what their solutions to these problems are. Method: This is a qualitative study. An initial study was performed by open-ended interviews with the CEOs of the Swedish Franchisor organization and the CEO of the Swedish Franchisee organization. Thereafter, ten semi-structured telephone interviews were held with the upper management at Swedish restaurant franchisor companies. Saturation was achieved after 6-8 interviews and the data was analyzed thematically. Results & Conclusions: Small franchisors focus on concept development, finding capital and finding franchisees. Two of the smaller franchisors used crowdfunding to finance their expansion. Larger franchisors focus on standardization, improving their quality and on brand building. The conclusion is that there are significant differences in the CSFs for small and large franchisors. Suggestions for future research: This study is limited in scope and limited in time. For future research, we would recommend a longitudinal study of several newborn franchise systems, to study them over several years and to see which CSFs are more important at different growth stages. Another research approach could be to rank the CSFs by using a quantitative method and work with a larger sample frame of franchisors. Or to study our fastest growing respondent. Contribution of the thesis: The main contribution to literature is that small franchisors focus on selecting the right franchisees and locations, large franchisors focus on developing the concept and on standardization. The main managerial implication is that franchisors of all sizes need to take a broad perspective and plan for different expansion phases. Keywords: Franchising, Franchisee, Franchisor, Critical Success Factors, CSFs, Restaurant Chain, Fast-Food chain, life cycle, expansion, barriers. / This is a study of what the most important tasks are to successfully expand ten franchised restaurant chains in Sweden. These tasks have been studied in various industries and are commonly referred to as "Critical Success Factors." It is interesting to study these tasks since the upper management in any company and industry need to be aware of what the most important tasks are for their company, as well as the need of measuring these tasks. The result of the study was that restaurant franchisors seem to have different CSFs depending on their size. Small franchisors focus more on, e.g., concept development, whereas large franchisors focus more on, e.g., standardization. The managerial implication is that managers in expanding franchise systems need to be aware that the CSFs change over time.

Dans ce travail de thèse, nous avons analysé les résidus des plusieurs contaminants anthropiques dans des prédateurs de la chaîne alimentaire aquatique et des proies de la chaîne terrestre. En effet, la loutre, le grand cormoran et le silure sont prédateurs piscivores au sommet de la chaîne alimentaire, les pesticides organochlorés, les PCBs et les éléments traces métalliques (plomb, cadmium, cuivre et mercure) ont été détectés dans tous les foies de ces prédateurs prélevés dans les bassins de la Loire en France. Les PCBs sont les organochlorés les plus répandus dans les trois espèces, suivi des DDTs. Les valeurs maximales de PCBs ont atteint 1,61, 1,96 et 0,28 mg/kg de poids frais pour les cormorans, les loutres et les silures, respectivement. La concentration du mercure a dépassé la limite toxique pour plus de 40 % des cormorans analysés. L‘effet « cocktail » de ces contaminants sur les trois espèces n‘est pas étudié dans cette thèse. Cependant, Les concentrations des organochlorés et des éléments traces dans ces prédateurs sont généralement modestes ou faibles. Ainsi, Il nous semble que ces contaminants ne constituent pas une menace pour la conservation de ces espèces à court ou moyen terme. Par ailleurs, dans le réseau trophique terrestre, nous avons trouvé que trois rodenticides anticoagulants la chlorophacinone, la bromadiolone et le brodifacoum s‘accumulent dans les limaces de la manière rapide et stable au cours de temps, par contre aucune mortalité n‘a été observée chez les limaces. Le brodifacoum a été détecté dans plus de 90 % des limaces prélevées sur le terrain, et nous avons constaté que ces limaces représentaient un risque élevé d'empoisonnement secondaire pour trois de leurs prédateurs, le hérisson européen, la musaraigne commune et l'étourneau sansonnet. On pourrait donc confirmer que les invertébrés constituent une source non négligeable de rodenticides pour leurs prédateurs.L‘objectif de cette thèse est de montrer l‘influence du régime alimentaire sur la contamination des proies, des prédateurs et d‘évaluer les risques toxicologiques pour ces espèces / In this work, we analyzed the residues of several anthropogenic contaminants in predators of the aquatic food chain and prey of the terrestrial chain. The otter, the great cormorant and the catfish are piscivorous predators at the top of the food chain. Organochlorine pesticides, PCBs and trace elements (lead, cadmium, copper and mercury) were detected in all these predators collected from the basins of the Loire in France. Residue level of PCBs in these predators was the highest followed by DDTs and maximal PCB values reached 1.61, 1.96, and 0.28 mg/kg wet weight for cormorants, otters, and catfish, respectively. The concentration of mercury exceeded the toxic thresholds for more than 40% of the cormorants analyzed. The possible combined effect of these contaminants on the three species has not been studied in this thesis. However, the concentrations of organochlorines and trace elements are generally modest or low. Thus, it seems that these contaminants do not constitute a major threat to the conservation of these species for the short or medium term. Furthermore, in the terrestrial food chain, we found that three anticoagulant rodenticides chlorophacinone, bromadiolone and brodifacoum accumulate in slugs in a stable way over the time, whereas no mortality was observed in slugs. Brodifacoum was detected in more than 90% of the slugs collected in the field, and we found that these slugs represented a high risk of secondary poisoning for three of their predators, European hedgehog, common shrew and European starling. Therefore, it could be confirmed that invertebrates constitute a non-negligible source of rodenticides for their predators.The objective of this thesis is to show the influence of the diet on the contamination of prey, predators and to evaluate the toxicological risks for these species

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Master of Science / Department of Biology / Keith B. Gido / Nonnative species represent a major threat to the continued persistence of native fishes globally, especially in the Colorado River Basin of western North America, where there are now more nonnative than native fishes. In the upper Gila River, a tributary of the Colorado, numerous nonnative fishes have established populations, and predation by these nonnatives has been linked to extirpation of native fishes under low-flow conditions at some locations. Historically, the upper Gila lacked a top piscivore, and it is unclear what mechanisms have allowed the establishment of nonnative piscivores and resultant extension in food chain length. To investigate the phenomenon of increased food chain length through nonnative introductions we explored the influence of autochthonous energy availability on nonnative predator abundance, food chain length, and abundance of other trophic levels. Predictions were that increased basal energy availability would lead to increased nonnative predator abundance and thus increased food chain length, based upon predictions from food web theory. Annual production and biomass of four trophic levels measured across six longitudinally-positioned sites were calculated between June 2008 and June 2009 to test these predictions. In addition, energy demand of trophic levels relative to energy supply was compared across sites using a quantitative food web approach, to evaluate energy limitation across trophic levels. Primary production was found to vary considerably across the upper Gila (1,677-16,276 kcal m-2 yr-1), but production and biomass of other trophic levels was not related to this gradient as predicted. In addition, food chain length demonstrated a marginally-significant negative relationship with primary production (R[superscript]2=0.42, d.f.=5, p=0.16), which was in contrast with predicted responses. These results suggest that energy availability does not appear to be a limiting factor to the production or biomass of consumers. The influence of other mechanisms on food chain length in the upper Gila River, in particular disturbance frequency and intensity, deserve further investigation.

Microplastic pollution (particles < 5mm) is one of the most widespread impacts from modern society. Here, microplastic impacts were investigated through experimental assessments considering different exposure scenarios using mussels and micro-PVC as models. These aimed to investigate mussels\' physiological signs of stress under acute and chronic exposures and microplastics transference, assimilation and retention along food chains. In acute exposures, PVC intake affected mussels\' physiology over time, also influenced by plastics additives and particle concentration. Interactions among exposure factors (time, presence of additives and concentration) were more relevant than their individual effect, indicating the singularity of each contamination scenario. Long-term contact did not affect mussels, indicating the influence of time to acclimation. Microplastics were not assimilated and retained along food chains, but only biotransferred from prey tissues to predators\' tract, showing the influence of prey contamination on the effectiveness of microplastics biotransference. To evaluate risks in nature, microplastic ingestion was investigated in mussels from the Santos Estuary. Santos Estuary contained microplastics in 75% of sampled mussels, an issue of environmental and human concern. This study illustrated that microplastics impacts on mussels vary with microplastics characteristics, exposure scenario and species vulnerability, highlighting the need for more toxicological and risk evaluation studies. / Os microplásticos (< 5mm) são um dos impactos mais difundidos da sociedade moderna. Aqui, eles foram estudados em ensaios experimentais, considerando diferentes composições de exposição de mexilhões à micro-PVCs. O objetivo foi investigar: sinais fisiológicos de estresse sob exposições aguda e crônica; e transferência, assimilação e retenção de microplásticos em cadeias tróficas. Para avaliar seus potenciais riscos na natureza, a ingestão por mexilhões também foi investigada no Estuário de Santos. As exposições agudas afetaram a fisiologia dos mexilhões, sendo influenciadas pelo tempo e concentração de exposição, e pela presença de aditivos plásticos. Interações entre esses fatores (tempo, concentração e aditivos) foram mais relevantes do que eles individualmente, sugerindo a singularidade dos cenários de poluição. A exposição de longo prazo não afetou os mexilhões, indicando a influência do tempo na aclimatação ao microplástico. O PVC não foi assimilado e retido nas cadeias tróficas, mas biotransferido do tecido das presas para o trato dos predadores, mostrando a influência do estado da presa na efetividade da biotransferência dos microplásticos. Dentre os mexilhões coletados, 75% estavam contaminados, revelando uma importante questão socioambiental. Esse trabalho ilustrou a complexidade dos impactos dos microplásticos para a biota marinha, ressaltando a necessidade de mais estudos sobre seus riscos.

Isótopos estáveis de 13C e 15N de fontes basais e consumidores foram utilizados para descrever e quantificar as fontes de matéria orgânica que sustentam as teias alimentares em riachos da Floresta Atlântica em um gradiente altitudinal (Floresta Montana, Submontana e Terras Baixas) e em riachos com diferentes usos do solo floresta, cultivo de eucalipto e pastagem). Os estudos foram realizados no Parque Estadual da Serra do Mar Núcleos Picinguaba e Santa Virgínia e no seu entorno. No gradiente altitudinal os resultados indicam que em floresta Montana os consumidores mostraram dependência das fontes autóctones (principalmente seston), em Submontana as fontes autóctones também são as que mais contribuem para os consumidores, principalmente perifíton. Em Terras Baixas as plantas C3 entram como contribuintes nas teias alimentares, contudo os consumidores continuam assimilando mais C e N do perifíton e seston. Nos diferentes usos do solo, as fontes basais tiveram diferenças isotópicas, com valores mais negativos de 13C em floresta e menos negativos nos riachos alterados e 15N mais positivo na pastagem. A comunidade em riachos de floresta assimila C e N proveniente do seston, enquanto que em cultivo de eucalipto as fontes autóctones (perifíton e seston) contribuem com mais de 70% e gramíneas C4 com 14%. Os riachos de pastagem são ambientes heterotróficos com grande dependência das fontes alóctones (plantas terrestres C3 e gramíneas C4). Destaca-se um aumento na contribuição das fontes alóctones à medida que se muda a cobertura vegetal do entorno, em floresta a contribuição alóctone é de 3%, cultivo de eucalipto 23% e pastagem 58%. Isso se deve principalmente a entrada de C4 nas teias alimentares. / 13C and 15N stable isotopes of basal sources and consumers were used to describe and quantify sources of organic matter supporting food webs in streams of the Atlantic Forest along an elevation range (montane forest, sub-montane and lowland) and in streams with different land uses (forest, eucalyptus and pasture). Studies were carried in the Parque Estadual da Serra do Mar - Picinguaba and Santa Virginia nucleous and its surroundings. Along the elevation range results indicate that consumers in Montane forest showed dependence on autochthonous sources (mainly seston). In sub-montane autochthonous sources are also those that contribute most to consumers, mainly periphyton. In lowlands C3 plants come as contributors in food webs, however most consumers remain assimilating C and N from the seston and periphyton. The basal sources had different isotopic signatures indifferent land uses, with more negative values of 13C in forest streams and less negative in altered streams and 15N values more positive in pasture. The community forest streams assimilated C and N from seston, while in the cultivation of eucalyptus autochthonous sources (periphyton and seston) contribute more than 70% and C4 grasses with 14%. The pasture streams are heterotrophic environments with high reliance on allochthonous sources (C3 terrestrial plants and C4 grasses). Increase in the contribution of allochthonous sources was observed in the following order: forest (3%), eucalyptus (23%), and pasture (58%). This is mainly due to entry of C4 plants in food webs.