Introdução: Apesar de apresentar grandes prevalências e impactos, a depressão no período perinatal é subdiagnosticada, subtratada e ainda não possui uma consistente diferenciação dos episódios depressivos em outras épocas de vida. Sua etiologia engloba aspectos psicossociais e biológicos ainda controversos. Algumas mulheres expostas a estressores ambientais não desenvolvem estados depressivos no período periparto. A predisposição genética pode ser uma explicação. Estudos que avaliaram o papel de fatores genéticos demonstraram resultados inconsistentes, possivelmente por diferenças metodologias, como a época e a forma da mensuração dos sintomas depressivos, os fatores ambientais avaliados, as metodologias de análise e as diferenças étnicas entre as amostras. Este estudo objetivou investigar interações genético-ambientais na etiologia da depressão periparto, tendo como hipóteses: a) eventos estressores ou a experiência subjetiva de estresse associar-se-iam a uma maior probabilidade de desenvolvimento de sintomas depressivos perinatais em indivíduos portadores de polimorfismos associados com maior vulnerabilidade; b) haveria um efeito diferencial da vulnerabilidade genética aos estressores de acordo com a cor da pele do indivíduo. Métodos: 2847 gestantes de uma coorte prospectiva provenientes de duas cidades brasileiras foram avaliadas no pré-natal e no puerpério. Exploraram-se associações entre variáveis sociodemográficas, e fatores estressores e protetores ambientais com o desenvolvimento de sintomas depressivos perinatais, considerando a predisposição biológica, avaliada por meio de dois polimorfismos funcionais, localizados na região promotora do gene para o transportador de serotonina (5HTTLPR) e do gene para o receptor do hormônio liberador de corticotrofina (CRH1). As associações entre variáveis foram testadas por regressão de Poisson. Testaram-se modelos explicativos para os desfechos utilizando a modelagem de equações estruturais. As interações genético-ambientais foram avaliadas por regressão de Poisson e modelos multigrupos. Resultados: 2822 mulheres foram avaliadas na gestação e 1860 reavaliadas no puerpério. A prevalência de provável depressão na gestação foi de 24,4% e no puerpério, 15,9%. Os modelos com hipóteses associativas para a explicação dos desfechos mostraram que o relato de eventos estressores no último ano teve grande parte do seu efeito mediado pelos níveis de estresse percebido. Estresse percebido foi fator de risco tanto para mulheres brancas como negras, mas relato de eventos estressores foi fator de risco apenas para mulheres brancas. Houve um papel de moderação do 5-HTTLPR e dos haplótipos do CRH1 no efeito ambiental nos estados depressivos perinatais, ampliado quando a cor da pele da mãe foi considerada. Na presença de baixos indicadores de estresse, a presença de nenhuma ou uma cópia do haplótipo do CRH1 foi um fator protetor entre mulheres negras. Na depressão puerperal, ser carreadora da variante longa do 5HTTLPR, teve um efeito protetor na ausência de eventos estressores no último ano. Ao separar por cor, este efeito protetor manteve-se significativo apenas entre mulheres de cor negra. Conclusões: No que se refere à vulnerabilidade genética, os resultados apontaram para algumas semelhanças entre a depressão perinatal e a depressão em outros momentos da vida. A depressão perinatal pode ser um evento importante para o entendimento dos aspectos genéticos da fisiopatologia da depressão em outros momentos da vida. / Introduction: Although presents large prevalences and impacts, peripartum depression are under detected, under assisted and yet do not have a consistent differentiation of depressive episodes at other phases of life. Its etiology includes psychosocial and biological aspects still controversial. A few women exposed to environmental stressors did not develop peripartum depressive states. Genetic predisposition may be an explanation. Studies evaluating the role of genetic factors have shown inconsistent results probably due to methodological differences, such as the period and the way of measurement of depressive symptoms, environmental factors evaluated, analysis methods and ethnic differences between the samples. This study aimed to investigate gene-environment interactions in the etiology of peripartum depression, through these hypotheses: a) the occurrence of stressful events or the subjective experience of stress would associate themselves to a greater probability of developing perinatal depressive symptoms in subjects with polymorphisms associated with greater biological vulnerability; b) there would be a differential effect of genetic vulnerability to environmental stressors according to the individual\'s skin color. Methods: 2847 pregnant women from two Brazilian cities in a prospective cohort study were assessed during the prenatal and postpartum period. Associations between socio-demographic, stressors and protective factors with the development of perinatal depressive symptoms was explored. It was considered the biological predisposition evaluated by two functional polymorphisms located in the promoter region of the gene for the serotonin transporter (5HTTLPR) and the gene for the corticotrophin releasing hormone receptor (CRH1). Associations between variables were tested by Poisson regression. We tested explanatory models for outcomes using structural equation modeling. The geneticenvironmental interactions were assessed by Poisson regression and multigroups models. Results: 2822 women were assessed during pregnancy and 1860 were reassessed during the postpartum period. The prevalence of probable depression during pregnancy was 24.4% and 15.9% during the postpartum period. Models with associative hypotheses to explain the outcomes showed that the report of stressful events in the last 12 months had much of its effect mediated by perceived stress levels. Perceived stress was a risk factor for both white women and black women, but reports of stressful events was a risk factor only for white women. There was a moderating role of the 5-HTTLPR and haplotypes of CRHR1 in the environmental effects on perinatal depressive states. These findings are even more significant when skin color was considered. In the presence of low stress indicators, have no copies or one copy of haplotype CRH1 was a protective factor among black women. In postpartum depression, be a carrier of the long variant of the 5 HTTLPR, had a protective effect in the absence of stressful events in the last year. If we separate by color, this protective effect remained significant only among black women. Conclusions: With regard to genetic vulnerability, the results points to similarities between peripartum depression and depression during other phases of life. Perinatal depression can be an important event for the understanding of the genetic aspects of the pathophysiology of depression.

Introdução: Apesar de apresentar grandes prevalências e impactos, a depressão no período perinatal é subdiagnosticada, subtratada e ainda não possui uma consistente diferenciação dos episódios depressivos em outras épocas de vida. Sua etiologia engloba aspectos psicossociais e biológicos ainda controversos. Algumas mulheres expostas a estressores ambientais não desenvolvem estados depressivos no período periparto. A predisposição genética pode ser uma explicação. Estudos que avaliaram o papel de fatores genéticos demonstraram resultados inconsistentes, possivelmente por diferenças metodologias, como a época e a forma da mensuração dos sintomas depressivos, os fatores ambientais avaliados, as metodologias de análise e as diferenças étnicas entre as amostras. Este estudo objetivou investigar interações genético-ambientais na etiologia da depressão periparto, tendo como hipóteses: a) eventos estressores ou a experiência subjetiva de estresse associar-se-iam a uma maior probabilidade de desenvolvimento de sintomas depressivos perinatais em indivíduos portadores de polimorfismos associados com maior vulnerabilidade; b) haveria um efeito diferencial da vulnerabilidade genética aos estressores de acordo com a cor da pele do indivíduo. Métodos: 2847 gestantes de uma coorte prospectiva provenientes de duas cidades brasileiras foram avaliadas no pré-natal e no puerpério. Exploraram-se associações entre variáveis sociodemográficas, e fatores estressores e protetores ambientais com o desenvolvimento de sintomas depressivos perinatais, considerando a predisposição biológica, avaliada por meio de dois polimorfismos funcionais, localizados na região promotora do gene para o transportador de serotonina (5HTTLPR) e do gene para o receptor do hormônio liberador de corticotrofina (CRH1). As associações entre variáveis foram testadas por regressão de Poisson. Testaram-se modelos explicativos para os desfechos utilizando a modelagem de equações estruturais. As interações genético-ambientais foram avaliadas por regressão de Poisson e modelos multigrupos. Resultados: 2822 mulheres foram avaliadas na gestação e 1860 reavaliadas no puerpério. A prevalência de provável depressão na gestação foi de 24,4% e no puerpério, 15,9%. Os modelos com hipóteses associativas para a explicação dos desfechos mostraram que o relato de eventos estressores no último ano teve grande parte do seu efeito mediado pelos níveis de estresse percebido. Estresse percebido foi fator de risco tanto para mulheres brancas como negras, mas relato de eventos estressores foi fator de risco apenas para mulheres brancas. Houve um papel de moderação do 5-HTTLPR e dos haplótipos do CRH1 no efeito ambiental nos estados depressivos perinatais, ampliado quando a cor da pele da mãe foi considerada. Na presença de baixos indicadores de estresse, a presença de nenhuma ou uma cópia do haplótipo do CRH1 foi um fator protetor entre mulheres negras. Na depressão puerperal, ser carreadora da variante longa do 5HTTLPR, teve um efeito protetor na ausência de eventos estressores no último ano. Ao separar por cor, este efeito protetor manteve-se significativo apenas entre mulheres de cor negra. Conclusões: No que se refere à vulnerabilidade genética, os resultados apontaram para algumas semelhanças entre a depressão perinatal e a depressão em outros momentos da vida. A depressão perinatal pode ser um evento importante para o entendimento dos aspectos genéticos da fisiopatologia da depressão em outros momentos da vida. / Introduction: Although presents large prevalences and impacts, peripartum depression are under detected, under assisted and yet do not have a consistent differentiation of depressive episodes at other phases of life. Its etiology includes psychosocial and biological aspects still controversial. A few women exposed to environmental stressors did not develop peripartum depressive states. Genetic predisposition may be an explanation. Studies evaluating the role of genetic factors have shown inconsistent results probably due to methodological differences, such as the period and the way of measurement of depressive symptoms, environmental factors evaluated, analysis methods and ethnic differences between the samples. This study aimed to investigate gene-environment interactions in the etiology of peripartum depression, through these hypotheses: a) the occurrence of stressful events or the subjective experience of stress would associate themselves to a greater probability of developing perinatal depressive symptoms in subjects with polymorphisms associated with greater biological vulnerability; b) there would be a differential effect of genetic vulnerability to environmental stressors according to the individual\'s skin color. Methods: 2847 pregnant women from two Brazilian cities in a prospective cohort study were assessed during the prenatal and postpartum period. Associations between socio-demographic, stressors and protective factors with the development of perinatal depressive symptoms was explored. It was considered the biological predisposition evaluated by two functional polymorphisms located in the promoter region of the gene for the serotonin transporter (5HTTLPR) and the gene for the corticotrophin releasing hormone receptor (CRH1). Associations between variables were tested by Poisson regression. We tested explanatory models for outcomes using structural equation modeling. The geneticenvironmental interactions were assessed by Poisson regression and multigroups models. Results: 2822 women were assessed during pregnancy and 1860 were reassessed during the postpartum period. The prevalence of probable depression during pregnancy was 24.4% and 15.9% during the postpartum period. Models with associative hypotheses to explain the outcomes showed that the report of stressful events in the last 12 months had much of its effect mediated by perceived stress levels. Perceived stress was a risk factor for both white women and black women, but reports of stressful events was a risk factor only for white women. There was a moderating role of the 5-HTTLPR and haplotypes of CRHR1 in the environmental effects on perinatal depressive states. These findings are even more significant when skin color was considered. In the presence of low stress indicators, have no copies or one copy of haplotype CRH1 was a protective factor among black women. In postpartum depression, be a carrier of the long variant of the 5 HTTLPR, had a protective effect in the absence of stressful events in the last year. If we separate by color, this protective effect remained significant only among black women. Conclusions: With regard to genetic vulnerability, the results points to similarities between peripartum depression and depression during other phases of life. Perinatal depression can be an important event for the understanding of the genetic aspects of the pathophysiology of depression.

Seed size is regarded as a functional trait with very important consequences for the fitness of plant species. Seedlings emerging from larger seeds are more competitive but are more costly to produce than seedlings from smaller seeds. Seed size is also a trait with transgenerational effects, affecting both the fitness of the parent as well as that of the offspring. Theory on the evolution of offspring size predicts an optimum balance between size and number, seen from the parent's perspective; while empirical studies often show selection for larger seeds, seen from the offspring's perspective. Seed size selection arising from post germination traits is, however, often not unidirectional, nor operating with the same strength in all life history stages of the plant. Seed size selection is also environmentally dependent. Even environmental influence might not operate with the same consistency and strength uniformly through the plant's life cycle. This dissertation is intended to study these questions concerning the dynamics of seed size selection in the wild. This work is to my knowledge, the first to document how seed size selection operates through the whole life cycle, with naturally germinated annual plants from the Sonoran Desert. In my first chapter I explored the offspring fitness consequences of seed size in a multiyear observational study using plant demography and relating vital rates (germination, survival, and fecundity) to the size of the seeds that originate individual plants and the environmental variables of precipitation and competition. I detected positive directional selection operating both through survival and fecundity. Water availability increased both survival and fecundity but also strengthened survival selection and had no effect on fecundity selection. Competition detrimental effects were only observed in fecundity but not in plant survival. In my second chapter I ask whether seed size-specific germination could influence seed size selection later in the life cycle. We found that because germination is differential in relation to seed size, the time of optimal conditions for germination in the field would determine the variance of seed size in the germinated fraction and thus influencing the strength of seed size selection operating through survival. In my third chapter I explored the dispersal consequences of phenotypic plasticity in seed provisioning. We found that mother plants that experienced more competition made smaller seeds and affected the seed dispersal process. Smaller seeds were better able to disperse farther away from their mothers and therefore increased their probability of escaping competition in the next growing season. These studies demonstrated that seed size selection varies through the life cycle and in intensity depending on interactions with the environment.

The impact of the relative richness or poverty of the external environment on development has been demonstrated in a variety of species and for a number of physical and cognitive processes. However, a dichotomy exists in the present literature, wherein the physical and social environments are compartmentalized. The present study investigated the potential longitudinal interaction between the social and physical environments on early cognitive development and emotional reactivity. Bobwhite quail (Colinus virginianus) were exposed to different part-time combinations of social and physical enrichment over the first 96 hours following hatch. Developmental trajectories were explored using repeated non-identical maze tasks. The experiment was inconclusive as to the effects of enrichment; however a distinct trend arose as a main effect of age. Chicks were significantly less willing to explore and solve the maze at 72 and 96 hours. Potential explanations concerning experience and physiological maturation are discussed along with sources of variability.

The study was done in Adaa district which is one of the 12 districts in East Shoa zone in Oromia regional state of Ethiopia. It is located southeast of Addis Ababa at 38o51’ 43.63’’ to 39o04’ 58.59’’ E and 8o46’ 16.20’’ to 8o59’ 16.38’’ N, on the western margin of the Great East African Rift Valley. The altitude ranges from 1 500 to ≥ 2 000 meters above sea level. The district has a high potential for mixed livestock and crop production systems. The purpose of this study was to make up for the paucity of information on livestock and environment interaction by assessing the relationship of livestock, soil, water, land, climate and crops under mixed crop-livestock production systems in central Ethiopian highlands. The objectives of the study were: (a) to assess the effect of change in land management on carbon storage and the contribution of livestock to carbon storage; (b) to examine the impact of livestock on natural resources and the environment; (c) to assess the effects of the change in traditional agricultural practices, expansion of factories, slaughter houses, greenhouses and flower farms on water and soil quality; (d) to evaluate the effect of climate change on livestock production under small-scale agriculture; and (e) to recommend options for mitigation and adaptation to environmental changes. The research design was non-experimental and did not involve the manipulation of the situation, circumstances or experiences of the interviewees. The design was comparative research that compared two or more groups on one or more variables, such as the effect of agricultural land use management, tillage type etc. on carbon storage in the soil. This research also applied a longitudinal design that examined variables such as the performance exhibited by groups over time. Purposive sampling was often used to measure the effect of agricultural, industrial effluent and human interferences on the environment by measuring nutrient contents at sources in the soil, water and manure. Biological data were complemented by key socio-economic survey by interviewing individual farmers and focus groups from sampling sites. Secondary data were also reviewed to measure soil degradation and run-off attributed to livestock. Results showed that animal waste and farmyard manure had the highest contribution in the addition of carbon in the soil. This implied that for most of carbon inputs livestock products and by-products had a greater place in the carbon sink. Therefore, livestock production could be considered as one of the major agricultural production systems in soil carbon storage. Similarly, livestock production systems also play an important role in maintaining the eco-system balance through nutrient recycling. On the average, the number of livestock per household for most species increased during the Derge regime in the 1990s compared to the Haile Sellassie regime in the 1970s when people did not own land; and then the number declined in the 2000s except for equines, crossbreeds and oxen. The change to crop intensification led to the change in the purpose for livestock keeping. Farmers started keeping certain types of animals for specific purposes unlike before when livestock was kept for prestige and economic security. The major drive for the change of attitude towards the purpose of keeping livestock was scarcity of resources, mainly feed and water. Equine ownership has significantly increased due to their low off-take rate and their feeding habits which allowed them to survive in harsh environments where feed resources were extremely scarce. There was a significant difference in crop response to manure application. Vegetables produced higher yields with manure than chemical fertilizers. Cereals on the other hand responded more to chemical fertilizers than to manure. Therefore, combining manure and chemical fertilizers was the best option for the sustainability of crop production in the study area. Some of the limitations to the use of manure as an organic fertilizer were inadequate manure production, high labour cost, bulkiness and high cost of transport to the fields and weed infestation. Manure management systems in the study area were affected by livestock husbandry practices. Only crossbred cattle (5%) were zero-grazed and used; and manure was stored in pits as slurry. Indigenous cattle were grazed outdoors in the fields during the day and at night they were kept in kraals near homesteads. There was a substantial loss of nutrients during the day when animals were grazing in the fields through leaching and trampling of dung and urine patches. Indoor or zero grazing of livestock could reduce nutrient losses. The use of manure as fuel in the study area had no significant effect on CO2 emissions at household or local level, but had a negative impact on soil organic carbon storage and soil fertility. Therefore, for improved yield and balanced eco-systems manure burning has to be replaced by other alternative energy sources such as bio-gas and kerosene. The largest carbon equivalent emissions were from CH4 (72.6%), N2O (24%) and CO2 (3.4%) which indicated the need to improve livestock and manure management systems under smallholder agriculture. Overall, there was an indication of a decline in water resources on per capita basis. The major contributing factors were combined pressure of human and animal population on natural resources that led to excessive deforestation, loss of biological diversity, overgrazing, soil degradation and various forms of pollution and contamination. The global climate change also played a role in the decline in water resources due to the decrease in annual precipitation and increasing temperatures. Urbanization and economic growth increased the demand for milk and meat, which required additional water use for each unit of increased animal protein. The demand for milk and meat is expected to double in the next 20 years with an annual growth rate of between 2.5 to 4%. From the sixty-year meteorological data (1951-2009) there was an established increase in rainfall by 2% per annum; and maximum and minimum temperature by 0.08oC per decade, which amounted to a cumulative temperature increase of 0.5oC in the last decade. The increase in precipitation and temperature favoured the adaption of lowland crops like maize and sorghum to highland agro-ecology. Climate prediction models forecasted that most of the highlands in Ethiopia will remain suitable for cereals like wheat and Teff for the next 50 to100 years. However, the perception of farmers indicated that they felt more heat and warm weather than they have experienced before. They reported that rainfall is now more erratic or comes late and stops earlier before plants completed their vegetative growth. / Environmental Sciences / D. Litt. et Phil. (Environmental Science)

Human interactions with nature is developed essentially by the forms and conditions of occupation of the territory, the appropriation of natural resources and social organization adopted to meet the needs expressed by the pattern of consumption of each society. This study aims to analyze the environmental interactions of the coastal plain associated with the mouth of the river San Francisco, city of Pacatuba, indicating the form of land use and occupation. The theoretical and conceptual framework to its foundations the research was based on Bertrand, which provides grants for integrated studies. Initially the studies were conducted to analyze the components of the physical environmental system focused by geology, climatology, geomorphology, water resources, soil conditions and vegetation cover, being carried out bibliographic, cartographic, documentary and electronic source. The methodological procedures consisted also in field trials which demonstrated the performance of various social actors in the landscape configuration of the coastal plain, like the economic activities - cocoicultura, shrimp, rice farming, poultry farming, fish farming, livestock, mining, artisanal fisheries and crafts. The study highlighted the importance of paleoclimate aspects that acted during the Quaternary the Brazilian coast, where relics forms coexist with the current. It is worth noting the presence of protected areas Biological Reserve of Santa Isabel, the Environmental Protection Area of the North Coast. The development of shrimp farming activity did emerge a major environmental problem that permeates local resizing the nutrient flow, decreasing the extraction of subsistence, in the mischaracterization of the mangrove ecosystem on the proletarianization of the local population, among others. The research is completed with the partitioning of the Coastal Plain Landscape Unit in landscape subunits, from the similarities of the environmental conditions and the use and occupation, synthesis of the relationship of its components. / As interações humanas com a natureza desenvolvem-se, essencialmente, pelas formas e condições de ocupação do território, da apropriação dos recursos naturais e da organização social adotada para o atendimento das necessidades expressas pelo padrão de consumo de cada sociedade. O presente estudo teve como objetivo analisar as interações socioambientais da planície costeira associada à foz do rio São Francisco, município de Pacatuba, indicando as formas de uso e ocupação do solo. O referencial teórico-conceitual que alicerçou a pesquisa foi baseado em Bertrand (1972), que oferece subsídios para os estudos integrados. Inicialmente os estudos foram conduzidos para análise dos componentes do sistema ambiental físico focalizados pela Geologia, Climatologia, Geomorfologia, recursos hídricos, Pedologia e cobertura vegetal, sendo realizados levantamentos bibliográficos, cartográficos, documentais e de fonte eletrônica. Os procedimentos metodológicos consistiram, ainda, em pesquisas de campo onde se constatou a atuação de diversos atores sociais na configuração da paisagem da planície costeira, a exemplo das atividades econômicas – cocoicultura, carcinicultura, rizicultura, avicultura, piscicultura, pecuária, mineração, pesca artesanal e artesanato. O estudo realizado destacou a importância dos aspectos paleoclimáticos que atuaram durante o Quaternário no litoral brasileiro, em que formas relíquias coexistem com as atuais. Vale destacar a presença das unidades de conservação Reserva Biológica de Santa Isabel e Área de Proteção Ambiental do Litoral Norte. O desenvolvimento da atividade da carcinicultura fez emergir uma grande problemática ambiental que perpassa por redimensionamentos locais no fluxo de nutrientes, na diminuição do extrativismo de subsistência, na descaracterização do ecossistema manguezal, na proletarização de parte da população ribeirinha, entre outros. A pesquisa é concluída com a compartimentação da Unidade de Paisagem Planície Costeira em Subunidades de Paisagem, a partir das similitudes dos condicionantes ambientais e do uso e ocupação do solo, síntese das relações dos seus componentes.

L’objectif principal de cette thèse a été d’établir une histoire précise des interactions sociétés-environnement durant le dernier millénaire dans deux zones de moyenne montagne, territoires particulièrement sensibles aux aléas naturels ainsi qu’aux évènements politiques, économiques et sociaux à travers un jeu de données multiples issues de différentes disciplines. L’étude de deux séquences sédimentaires lacustres de sites jurassien et alpin, grâce à l’outil palynologique - grains de pollen, spores et microfossiles non-polliniques -, particulièrement développé ici avec la haute-résolution, croisé avec l’étude des données historiques et archivistiques nous a permis, en plus de fournir un corpus complémentaire, de tester une approche comparative (données polliniques vs données cadastrales). Au lac de Remoray (Doubs, massif jurassien, 850 m d’altitude), l’étude a précisé le schéma du processus d’occupation de cette partie de la haute vallée du Doubs. Les données du haut Moyen Âge illustrent une fois de plus que l’idée qu’un désert forestier précédant l’arrivée des moines défricheurs est à nuancer. L’installation des communautés religieuses durant les XIème-XIIIème siècles, et l’influence des pouvoirs seigneuriaux sur cette zone stratégique, semblent toutefois l’étape clef dans la mise en place d’un peuplement durable. Les activités économiques se diversifient et prennent leur essor durant les siècles suivants bien que certaines périodes soient marquées de crises socio-politiques et traversées par les effets, plus ou moins ressentis, du Petit Âge Glaciaire. Il faudra attendre la transition XIXème-XXème siècle pour que les paysages sylvo-pastoraux que nous connaissons actuellement se mettent en place. Situé un peu plus au sud (Savoie, massif de la Chartreuse), notre second site d’étude trouve son origine dans ce qui donne à la montagne une autre identité : les risques naturels. Le site est le témoignage d’une zone dévastée en 1248 de notre ère par un immense glissement de terrain suite à la chute d’une partie du Mont Granier (1933 m d’altitude). Cet évènement, privant une partie de la vallée de cinq paroisses et d’un millier d’habitants, a engendré rapidement un nouveau territoire, aussi bien topographique, végétal que socio-économique. L’observation particulière des sédiments du lac Saint-André formé post-éboulement a offert l’occasion de suivre pas à pas cette reconquête végétale et humaine, appuyé par les approches géologiques, géographiques, archéologiques et historiques qui animent la recherche de façon récurrente. Les résultats obtenus témoignent d’une période de recolonisation végétale suivie d’une reconquête agro-pastorale relativement rapide, avec comme particularité la mise en place d’un territoire viticole. L’enregistrement sédimentaire particulier de ce lac a permis de suivre, en plus des indices d’une agriculture vivrière variée jusqu’au début du XXème siècle, le témoignage pollinique particulier de la vigne qui deviendra petit à petit une monoculture. / The main objective of this thesis was to establish a precise story of the interaction between societies and environment during the last millennium, in two zones of middle mountain area, which are particularly sensitive to the natural hazards as well as to the political, economic and social events, through a set of multiple data. The high-resolution study of two lacustrine sediment cores in two Jura and alpine sites, thanks to the palynological tool - pollen grains, spores and non-pollen palynomorphs - and the study of the historical and archival data allowed us, besides supplying a complementary corpus, to test a comparative approach (pollen vs cadastral data). At Lake Remoray (Doubs, Jura massif, 850 m asl.), the study specified the settlement process. The data of the Early Middle Ages, illustrate one more time that the idea that a forest desert preceding the arrival of the monks land-clearers is to be revised. The installation of religious communities during the XI-XIIIth centuries and the influence of the seigniorial powers in this strategic zone seem however the key stage in the implementation of a sustainable settlement. Economic activities diversify and take their development during the next centuries although certain periods are marked with sociopolitical crises and cross effects, more or less felt, of Little Ice Age. It will be necessary to wait for the XIX-XXth century transition to see the development of the recent silvo-pastoral landscape. Our second site of study finds its origin in what gives to the mountain another identity: the natural risks. The site is the testimony of a zone destroyed in 1248 AD by an immense landslide further to the fall of a part of the Mount Granier (Savoy, massif of the Chartreuse ; 1933 m asl.). This event, depriving the valley of five parishes and a thousand inhabitants quickly engendered a new territory, in terms of topographic, vegetal as well as socioeconomic aspect. The particular observation Lake Saint André lacustrine sequence, formed post-collapse, offered the opportunity to follow step by step this vegetal and human recovery, supported by the geological, geographical, archaeological and historic approaches which liven up the research in a recurring way. The results show of a period of vegetal recolonisation followed by a relatively fast agro-pastoral recovery with, as peculiarity, the implementation of a wine-making territory. The sedimentary recording of this lake allowed following, besides the indications of a varied food-producing farming till the beginning of the XXth century, the particular pollen testimony of the vineyard which will gradually become a monoculture.

The study was done in Adaa district which is one of the 12 districts in East Shoa zone in Oromia regional state of Ethiopia. It is located southeast of Addis Ababa at 38o51’ 43.63’’ to 39o04’ 58.59’’ E and 8o46’ 16.20’’ to 8o59’ 16.38’’ N, on the western margin of the Great East African Rift Valley. The altitude ranges from 1 500 to ≥ 2 000 meters above sea level. The district has a high potential for mixed livestock and crop production systems. The purpose of this study was to make up for the paucity of information on livestock and environment interaction by assessing the relationship of livestock, soil, water, land, climate and crops under mixed crop-livestock production systems in central Ethiopian highlands. The objectives of the study were: (a) to assess the effect of change in land management on carbon storage and the contribution of livestock to carbon storage; (b) to examine the impact of livestock on natural resources and the environment; (c) to assess the effects of the change in traditional agricultural practices, expansion of factories, slaughter houses, greenhouses and flower farms on water and soil quality; (d) to evaluate the effect of climate change on livestock production under small-scale agriculture; and (e) to recommend options for mitigation and adaptation to environmental changes. The research design was non-experimental and did not involve the manipulation of the situation, circumstances or experiences of the interviewees. The design was comparative research that compared two or more groups on one or more variables, such as the effect of agricultural land use management, tillage type etc. on carbon storage in the soil. This research also applied a longitudinal design that examined variables such as the performance exhibited by groups over time. Purposive sampling was often used to measure the effect of agricultural, industrial effluent and human interferences on the environment by measuring nutrient contents at sources in the soil, water and manure. Biological data were complemented by key socio-economic survey by interviewing individual farmers and focus groups from sampling sites. Secondary data were also reviewed to measure soil degradation and run-off attributed to livestock. Results showed that animal waste and farmyard manure had the highest contribution in the addition of carbon in the soil. This implied that for most of carbon inputs livestock products and by-products had a greater place in the carbon sink. Therefore, livestock production could be considered as one of the major agricultural production systems in soil carbon storage. Similarly, livestock production systems also play an important role in maintaining the eco-system balance through nutrient recycling. On the average, the number of livestock per household for most species increased during the Derge regime in the 1990s compared to the Haile Sellassie regime in the 1970s when people did not own land; and then the number declined in the 2000s except for equines, crossbreeds and oxen. The change to crop intensification led to the change in the purpose for livestock keeping. Farmers started keeping certain types of animals for specific purposes unlike before when livestock was kept for prestige and economic security. The major drive for the change of attitude towards the purpose of keeping livestock was scarcity of resources, mainly feed and water. Equine ownership has significantly increased due to their low off-take rate and their feeding habits which allowed them to survive in harsh environments where feed resources were extremely scarce. There was a significant difference in crop response to manure application. Vegetables produced higher yields with manure than chemical fertilizers. Cereals on the other hand responded more to chemical fertilizers than to manure. Therefore, combining manure and chemical fertilizers was the best option for the sustainability of crop production in the study area. Some of the limitations to the use of manure as an organic fertilizer were inadequate manure production, high labour cost, bulkiness and high cost of transport to the fields and weed infestation. Manure management systems in the study area were affected by livestock husbandry practices. Only crossbred cattle (5%) were zero-grazed and used; and manure was stored in pits as slurry. Indigenous cattle were grazed outdoors in the fields during the day and at night they were kept in kraals near homesteads. There was a substantial loss of nutrients during the day when animals were grazing in the fields through leaching and trampling of dung and urine patches. Indoor or zero grazing of livestock could reduce nutrient losses. The use of manure as fuel in the study area had no significant effect on CO2 emissions at household or local level, but had a negative impact on soil organic carbon storage and soil fertility. Therefore, for improved yield and balanced eco-systems manure burning has to be replaced by other alternative energy sources such as bio-gas and kerosene. The largest carbon equivalent emissions were from CH4 (72.6%), N2O (24%) and CO2 (3.4%) which indicated the need to improve livestock and manure management systems under smallholder agriculture. Overall, there was an indication of a decline in water resources on per capita basis. The major contributing factors were combined pressure of human and animal population on natural resources that led to excessive deforestation, loss of biological diversity, overgrazing, soil degradation and various forms of pollution and contamination. The global climate change also played a role in the decline in water resources due to the decrease in annual precipitation and increasing temperatures. Urbanization and economic growth increased the demand for milk and meat, which required additional water use for each unit of increased animal protein. The demand for milk and meat is expected to double in the next 20 years with an annual growth rate of between 2.5 to 4%. From the sixty-year meteorological data (1951-2009) there was an established increase in rainfall by 2% per annum; and maximum and minimum temperature by 0.08oC per decade, which amounted to a cumulative temperature increase of 0.5oC in the last decade. The increase in precipitation and temperature favoured the adaption of lowland crops like maize and sorghum to highland agro-ecology. Climate prediction models forecasted that most of the highlands in Ethiopia will remain suitable for cereals like wheat and Teff for the next 50 to100 years. However, the perception of farmers indicated that they felt more heat and warm weather than they have experienced before. They reported that rainfall is now more erratic or comes late and stops earlier before plants completed their vegetative growth. / Environmental Sciences / D. Litt. et Phil. (Environmental Science)