Made available in DSpace on 2014-12-17T13:56:52Z (GMT). No. of bitstreams: 1 PauloJLN_TESE.pdf: 2504955 bytes, checksum: 9bb23c4d630272ceb14882cfea97f217 (MD5) Previous issue date: 2012-04-13 / In the first decades of 20th century the just instituted Brazilian Republic faced the challenge to modernize the country. Considering that the progress was associated with the exhaustion of the forest reserves and with climatic changes, two big issues were seen as fundamental: To Fight the Droughts and To Defend the Forests; headed by professionals who were dedicated to these ideals. This research starts from the premise that these were the main challenges enforced by nature to the Brazilian development; the general objective was delimited in the search to understand the meaning and the conception of the natural world by this group of professionals who faced the shock between modernizing the country and conserving its natural resources. Aiming to contribute with the construction of the Brazilian environmental history and to bring historical elements to the debate about the environment in the country, the author concentrates his attention to the analyses, the discussions and the actions that preceded the regulation on the use of natural resources and the implementation of the environmental legislation in Brazil, occurred in 1934. The investigation uses as methodological basis the theoretical directions of environmental history, using sources of data still little explored and valued. In such way, it is taken as starting point some published papers about this subject during the period between 1889 and 1934 in two technical magazines the Revista Brazil Ferro-Carril and the Revista do Club de Engenharia. National engineering played a basic role in this process while arguing, projecting and constructing the development. The formulated proposals, after being divulged, had fomented the interchange with other professionals and had favored the advance of ambient questions in Brazil, in the sense to preserve natural resources, to construct more harmonic relations between the society and the nature and to equate the development with the environment preservation / Nas primeiras d?cadas do s?culo XX a rec?m institu?da Rep?blica brasileira enfrentou o desafio de modernizar o pa?s. Considerando que o progresso estava associado ao esgotamento das reservas florestais e ?s altera??es clim?ticas, duas grandes quest?es se destacaram como fundamentais: Combater as Secas e Defender as Florestas; encampadas por profissionais que se dedicaram a esses ideais. Esta investiga??o parte da premissa que esses foram os principais desafios impostos pela natureza ao desenvolvimento brasileiro. O objetivo geral foi delimitado na busca por entender a acep??o e a concep??o do mundo natural por esse conjunto de profissionais diante do embate entre modernizar o pa?s e conservar os recursos naturais. Visando contribuir com a constru??o da hist?ria ambiental brasileira e trazer elementos hist?ricos ao debate sobre o meio ambiente no pa?s, debru?a-se sobre as an?lises, as discuss?es e a??es que antecederam a regulamenta??o do uso dos recursos naturais e a implementa??o da legisla??o ambiental no Brasil, ocorrida em 1934. A investiga??o tem como aporte metodol?gico as dire??es te?ricas da hist?ria ambiental, utilizando fontes de dados pouco exploradas e valorizadas. Para tanto, toma-se como ponto de partida os artigos publicados sobre o tema no per?odo de 1889 a 1934 em dois peri?dicos t?cnicos a Revista Brazil Ferro-Carril e a Revista do Club de Engenharia. A engenharia nacional teve papel fundamental nesse processo ao discutir, projetar e construir o desenvolvimento. As propostas formuladas, ao serem divulgadas, fomentaram o intercambio com outros profissionais e favoreceram o avan?o das quest?es ambientais no Brasil, no sentido de preservar os recursos naturais, construir rela??es mais harm?nicas entre a sociedade e a natureza e equacionar o desenvolvimento e a preserva??o ambiental

Made available in DSpace on 2014-12-17T14:01:59Z (GMT). No. of bitstreams: 1 DanyheltonDFD.pdf: 1227676 bytes, checksum: c8754b4250e0bb6e5391c5ffbe8423a3 (MD5) Previous issue date: 2009-04-30 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Top-down (grazing) and bottom-up (nutrient, light) controls are important in freshwater ecosystems regulation. Relative importance of these factors could change in space and time, but in tropical lakes bottom-up regulation has to been appointed as more influent. Present study aimed to test the hypothesis that phytoplankton growths rate in Armando Ribeiro reservoir, a huge eutrophic reservoir in semi-arid region of Rio Grande do Norte state, is more limited by nutrient available then zooplankton grazing pressure. Bioassay was conduced monthly from September (2008) to August (2009) manipulating two levels of nutrients (with/without addition) and two level of grazers (with/without removal). Experimental design was factorial 2X2 with four treatments (X5), (i) control with water and zooplankton from natural spot ( C ), (ii) with nutrient addition ( +NP ), (iii) with zooplankton remove ( -Z ) and (iv) with zooplankton remove and nutrient addition ( -Z+NP ). For bioassay confection transparent plastic bottles (500ml) was incubate for 4 or 5 days in two different depths, Secchi`s depth (high luminosity) and 3 times Secchi`s depth (low luminosity). Water samples were collected from each bottle in begins and after incubates period for chlorophyll a concentration analysis and zoopalnktonic organisms density. Phytoplankton growths rates were calculated. Bifactorial ANOVA was performance to test if had a significant effect (p<0,005) of nutrient addition and grazers remove as well a significant interaction between factors on phytoplankton growths rates. Effect magnitude was calculated the relative importance of each process. Results show that phytoplankton growth was in generally stimulated by nutrient addition, as while zooplankton remove rarely stimulated phytoplankton growth. Some significant interactions happening between nutrient additions and grazers remove on phytoplankton growth. In conclusion this study suggests that in studied reservoir phytoplankton growth is more controlled by ascendent factors than descendent / A produ??o prim?ria dos ecossistemas aqu?ticos ? regulada por fatores ascendentes, (disponibilidade de luz e nutrientes), e por fatores descendentes (herbivoria). A import?ncia relativa desses fatores pode variar no tempo e no espa?o, mas em lagos tropicais tem sido sugerido que os fatores ascendentes s?o geralmente mais importantes. O presente estudo teve como principal objetivo testar a hip?tese de que o crescimento fitoplanct?nico no reservat?rio Armando Ribeiro Gon?alves, um grande reservat?rio eutr?fico na regi?o semi-?rida do Rio Grande do Norte, ? mais limitado pela disponibilidade de nutrientes do que pela press?o de herbivoria do zoopl?ncton. Bioensaios foram realizados mensalmente entre Setembro (2007) e Agosto (2008), manipulando-se dois n?veis de nutrientes (com/sem adi??o) e dois n?veis de herb?voros (com/sem remo??o). O desenho experimental foi do tipo fatorial 2X2 com quatro tratamentos (x5), (i) controle contendo a ?gua e o pl?ncton natural do ambiente ( C ), (ii) com adi??o de nutrientes ( +NP ), (iii) com remo??o de zoopl?ncton ( -Z ) e (iv) com remo??o de zoopl?ncton e adi??o de nutrientes ( -Z+NP ). Nos bioensaios foram incubadas garrafas pl?sticas transparentes de 500 mL por 4 ou 5 dias em duas profundidades distintas: na profundidade do disco de Secchi (alta luminosidade) e em uma profundidade 3x maior do que a anterior (baixa luminosidade). Amostras de ?gua foram coletadas de cada garrafa no inicio e ap?s o per?odo de incuba??o para an?lises das concentra??es de clorofila a e densidades de organismos zooplanct?nicos. Foi calculada a taxa de crescimento fitoplanct?nico. Uma ANOVA bifatorial foi realizada para testar se houve efeito significativo (p<0,05) da adi??o de nutrientes e da remo??o de herb?voros bem como uma intera??o significativa entre ambos os fatores sobre as taxa de crescimento do fitopl?ncton. A magnitude de cada efeito tamb?m foi calculada para quantificar a import?ncia relativa de cada processo. Os resultados mostram que o crescimento fitoplanct?nico foi geralmente estimulado pela adi??o de nutrientes enquanto a remo??o do zoopl?ncton raramente estimulou o crescimento fitoplanct?nico. Algumas intera??es significativas ocorreram entre os efeitos da adi??o de nutrientes e da remo??o de herb?voros sobre o crescimento fitoplanct?nico. Como conclus?o, esta pesquisa sugere que o crescimento fitoplanct?nico no reservat?rio estudado, ? mais fortemente controlado por fatores ascendentes do que por fatores descendentes

Made available in DSpace on 2014-12-17T15:03:19Z (GMT). No. of bitstreams: 1 GilsonDM.pdf: 1406431 bytes, checksum: ba7f7bf81266e47bd2a8051842929190 (MD5) Previous issue date: 2008-01-04 / The present research has the purpose of planning the management of the water resources of the Serid? River watershed, in the state of Rio Grande do Norte, Brazil. It has an emphasis on the amount of surface water available in this region, to provide a sustainable water supply. Based on data and information collected from public departments responsible for the management of the water resources of the Rio Grande do Norte state, well as on researches related to water resources , a watershed balance was done, and the results suggested the transposition of the waters from the Piranhas-A?u river watershed taken from the Oiticica and Armando Ribeiro Gon?alves reservoirs, integrated with the construction of 2 hidroelectrical plants and 2 elevation stations, to pump the amount of water needed to the expected demand in some public dams of the region until 2020. So, with the use of the surface water potential that exists in the region, it was demonstrated that, on the contrary of the public policies implemented in the past and in the current by the federal and state realm, it is possible to supply the currently water demands and also the future ones, in a sustainable way, without the need of importing outter water to the respective watershed. Finally, it was proposed the implementation of the Water Resources Plan in the Serid? region WRPS, aiming at providing an auto-sustainable development by significantly diminishing the effects of the dry seasons in that region, by considering the economic, social and environmental sustainability / O presente trabalho tem o prop?sito de planejar a utiliza??o e o manejo necess?rio dos recursos h?dricos da bacia do rio Serid?, no Estado do Rio Grande do Norte, com ?nfase na quantidade de ?gua superficial dispon?vel na regi?o, para abastecimento humano priorit?rio, de forma sustent?vel. Com base nos dados e informa??es coletadas junto aos ?rg?os p?blicos respons?veis pela gest?o dos recursos h?dricos no Estado do Rio Grande do Norte, bem como em outros trabalhos relacionados ? linha de pesquisa recursos h?dricos , foi efetuado o balan?o h?drico da bacia em estudo, cujo resultado sugeriu a transposi??o de ?guas da bacia do rio Piranhas-A?u, atrav?s da capta??o nas Barragens Oiticica e Eng? Armando Ribeiro Gon?alves, de modo integrado ? constru??o de 02 (duas) centrais hidrel?tricas e 02 (duas) esta??es elevat?rias, para bombear a ?gua necess?ria ? demanda prevista para o horizonte do ano 2020, para alguns a?udes p?blicos mais importantes da regi?o. Assim, com o aproveitamento do potencial h?drico superficial existente na regi?o, foi demonstrado que, ao contr?rio das pol?ticas p?blicas implementadas no passado e atuais pelos governos federal e estadual, pode-se atender ?s demandas h?dricas atualmente existentes e ?s futuras, de modo sustent?vel, sem a necessidade de importa??o de ?gua ex?gena ? bacia da regi?o. Por fim, foi proposta a implanta??o do Plano de Recursos H?dricos do Serid? PRHS, cujo principal objetivo consiste em propiciar o desenvolvimento auto-sustent?vel, diminuindo significativamente os efeitos das secas na regi?o Serid?, RN, com base nos princ?pios b?sicos de sustentabilidade econ?mica, social e ambiental, que nortearam o estudo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The Brazilian Northeastern Semi - arid during its occupation process was a region of stimulated economic value at the height of cattle breeding and also for its fertile lands, in which urban clusters formed, most of them close to intermittent rivers and streams.With the population densification in the urban nuclei resulted in the search for other places, and the settlement extended to the vast lands that sheltered the interior of these cities, mainly in the areas surrounded by isolated mountain ranges, known as upland forest, endowed with more humid climate, Lush forest and rising springs. Thus, they became favorable environments to the detriment of the natural system, by the continuous use of water, of its natural sources. It is known that the semi-arid region in the Northeast of Brazil suffers from water deficiency, where it is supplied by its hydrographic basins, whose sources are considered by law, permanent preservation areas - APP'S, and aim to establish the continuous sustenance of water supply. The current research seeks to analyze the socioenvironmental dynamics of the springs in Poço das Trincheiras, semi - arid region of Alagoas, with the spatial cut of the research in Serra do Poço, classified as an montane wet forest and due to environmental conditions, Thus forming the Serra do Poço Village. The municipality integrates the hydrographical region of the São Francisco River, and is drained by the sub - basins of the Rio Ipanema, Capiá and Riacho Grande. Poço das Trincheiras is bathed by intermittent rivers, but with many natural sources or watery eyes that originate on the mountains, coming from the outcrop of groundwater. Due to the water stresses and climatic anomalies faced by the living in the backlands, the springs are primordial sources of utilization of the population to overcome problems related to water scarcity, thus establishing a direct relationship between society and nature. For this, the developed research was outlined, starting from the systemic approach, having as category of geographic analysis the landscape. The methodological procedures consist of: bibliographic research, documentary research, experimental research and data treatment. A theoretical reference was made on the theme, later an integrated analysis of the landscape through the characterization of the environmental and socioeconomic constraints of the study area and, finally, the study of these sources. Finally, it is concluded that the springs areas protected by law evidenced in the municipality, especially in the Serra do Poço Village, are in small rural properties, totaling 12 (twelve), serving as local use for the community, whether in the cultivation of subsistence or watering of animals, some disturbed, others degraded by anthropic actions, but that there is no type of inspection or applicability of the legislation in the area. / O Semiárido nordestino brasileiro, durante o seu processo de ocupação, foi uma região de estimulado valor econômico no auge da criação bovina e também por suas terras férteis, nas quais se formaram aglomerados urbanos, a maioria próxima aos rios e riachos intermitentes. O adensamento populacional nos núcleos urbanos resultou na procura de outros locais, sendo que o povoamento se estendeu pelas vastas terras que abrigavam o interior dessas cidades, principalmente para áreas circundadas por serras isoladas, conhecidas como brejos de altitude, dotadas de clima mais úmido, mata exuberante e afloramento de nascentes. Assim, tornaram-se ambientes favoráveis, em face do sistema natural e do uso contínuo de água de suas fontes naturais. Sabe-se que a região semiárida, no Nordeste do Brasil, sofre com a insuficiência hídrica, que é suprida por suas bacias hidrográficas, cujas nascentes são consideradas por lei áreas de preservação permanente – APP’S – e visam a estabelecer o sustento contínuo do fornecimento de água. A pesquisa vigente busca em seu objetivo geral analisar a dinâmica socioambiental das nascentes em Poço das Trincheiras, no semiárido alagoano, sendo o recorte espacial da pesquisa situado em Serra do Poço, classificada como um brejo de altitude que, devido às condições ambientais, foi ocupada, formando assim o Povoado Serra do Poço. O município integra a região hidrográfica do rio São Francisco e é drenado pelas sub-bacias dos rios Ipanema, Capiá e Riacho Grande. Poço das Trincheiras é banhado por rios intermitentes, mas com muitas fontes naturais ou olhos d’água que se originam sobre as serras, provenientes do afloramento das águas subterrâneas. Devido aos estresses hídricos e às anomalias climáticas enfrentados pelos viventes dos sertões, as nascentes são fontes primordiais de utilização da população para vencer problemas relacionados à escassez de água, estabelecendo assim uma relação direta entre sociedade e natureza. Diante disso, a pesquisa desenvolvida delineou-se a partir da abordagem sistêmica, tendo como categoria de análise geográfica a paisagem. Quanto aos procedimentos metodológicos utilizados, eles consistiram em: pesquisa bibliográfica, pesquisa documental, pesquisa experimental e tratamento dos dados. Realizou-se um levantamento teórico acerca da temática, posteriormente fez-se uma análise integrada da paisagem através da caracterização dos condicionantes ambientais e socioeconômicos da área de estudo e, por fim, procedeu-se ao estudo dessas nascentes. Enfim, conclui-se que as nascentes, áreas protegidas por lei, evidenciadas no município, em especial no Povoado Serra do Poço, encontram-se em pequenas propriedades rurais, totalizando 12 (doze), servindo de uso local para a comunidade, seja no cultivo de subsistência ou na dessedentação de animais; verificou-se ainda que algumas são perturbadas e outras são degradadas pelas ações antrópicas, mas não existe nenhum tipo de fiscalização e nem aplicabilidade da legislação na área. / São Cristóvão, SE

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The species composition of the vegetation of Caatinga in three successional stages was characterized by sampling 20 installments, with 20x20m (400m2), in each stage.The initial stage corresponds to areas abandoned for nearly three years, the city of Poco Redondo; intermediate stage is located in the Monumento Natural Grota do Angico situated between the cities of Caninde do Sao Francisco and Poco Redondo, this site is in forest regeneration just over 20 years; and the late stage belongs to the Caatinga fragment found in the Fazenda Sao Pedro, Porto da Folha, which does not suffer human action for over 60 years.All subjects were considered from shrub - woody stratum with CAP (circumference at breast height 1.30 m)> 6 cm, had measured its circumference and height. The additive partitioning model used corresponds to the following formula: × = £ + Ò1 + Ò2, where × is the total diversity, £ is the mean diversity within plots, Ò1 is the diversity between plots of the same area, Ò2 is the diversity between the three areas.In the inicial area 15 species belonging to 8 families and 15 genera were identified. The density and total dominance found in this area were equivalents 818,75ind./ha and 0.89 m2/ha, respectively. The species with the highest importance value was Poincianella pyramidalis. The diversity index of Shannon-Wiener (H ´) and equability index of Pielou (J´) for this area were, respectively, 0.72 and 0.61. The intermediate area showed 15 families, 25 genera and 25 species. The total density was 1611.3 ind/ha, and total dominance was 3.31 m2/ha. P. pyramidalis was the species that showed the highest values of relative density, frequency, dominance and VI. The diversity index was 0.74 and the equability was 0.53. In the area in late stage 22 families, 40 genera and 46 species were identified. The total density was 2741.3 ind/ha and total dominance equal to 13.02 m2/ha. Bauhinia cheilantha had the highest VI. The H ´and J´ indices were 1.07 and 0.64, respectively. The results of the GLM from model ANOVA confirmed that the three areas differ from each other.The graphs obtained from NMDS showed from the ordering of the points that the areasare different in species richness. The analysis of additive partitioning of diversity showed that the £ component was the least contributed to the diversity ×, but the observed value for this component was higher than expected by the null model. The component Ò1 observed was lower than expected by the model, which illustrates the grouping of species generated by the limit of dispersion the same, which hampers migration among the remaining Caatinga.The component that best contributed to the diversity × was Ò2, highlighting the importance of replacement of species along the successional process. / A composicao de especies da vegetacao de Caatinga em tres estagios sucessionais foi caracterizada amostrando-se 20 parcelas, com 20x20m (400m2), em cada estagio.O stagio inicial corresponde a areas abandonadas ha cerca de 3 anos, no municipio de Poco Redondo; o estagio intermediario localiza-se no Monumento Natural Grota do Angico situado entre os municipios de Caninde do Sao Francisco e Poco Redondo, este local esta em regeneracao florestal a pouco mais de 20 anos; o estagio tardio pertence ao fragmento de Caatinga encontrado na fazenda Sao Pedro, Porto da Folha, que nao sofre acao antropica ha mais de 60 anos. Todos os individuos do estrato arbustivo ¡V arboreo com CAP (Circunferencia a altura do peito a 1,30m) > 6 cm tiveram sua circunferencia e altura aferidas.O modelo de particao aditiva utilizado corresponde a seguinte formula: × = £ + Ò1 + Ò2, onde × e a diversidade total, £e a diversidade media dentro das parcelas, Ò1 e a diversidade entre as parcelas da mesma area, Ò2 e a diversidade entre as tres areas. Na area inicial foram identificadas 15 especies pertencentes a 8 familias e 15 generos. A densidade e dominancia total encontradas nesta area foram equivalentes a 818,75 ind/ha e 0,89 m2/ha, respectivamente. A especie com maior valor de importanciafoi Poincianella pyramidalis. O indice de diversidade de Shannon-Wiener (H¡¦) e o indice de equabilidade de Pielou (J¡¦) foram, respectivamente, 0,72 e 0,61. A area intermediaria apresentou 15 familias, 25 generos e 25 especies. A densidade total foi 1611,3 ind/hae a dominancia total foi de a 3,31 m2/ha. P. pyramidalis foi a especie que apresentou os maiores valores de densidade relativa, frequencia, dominancia e VI. O indice de diversidade foi 0,74 e o de equabilidade foi 0,53. Ja na area tardia foram identificadas 22 familias, 40 generos e 46 especies. A densidade total foi 2741,3 ind/ha e a dominancia total 13,02 m2/ha. Bauhinia cheilanthaapresentou o maior VI. Os indices H¡¦ e J¡¦ foram 1,07 e 0,64, respectivamente.Os resultados do GLM do modelo ANOVA confirmaram que as tres areas diferem entre si. Os graficos obtidos a partir do NMDS mostraram a partir do ordenamento dos pontos que as areas sao diferentes em riqueza de especies.A analise da particao aditiva da diversidade mostrou que o componente £ foi o que menos contribuiu para a diversidade ×, porem o valor observado para tal componente foi superior ao esperado pelo modelo nulo. Ja o componente Ò1observado foi inferior ao esperado pelo modelo, o que ilustra o agrupamento de especies gerado pelo limite de dispersao das mesmas, o que dificulta a migracao entre os remanescentes de Caatinga. O componente que melhor contribuiu para a diversidade × foi Ò2, evidenciando a importancia da substituicao das especies ao longo do processo de sucessao.

Irrigation in the Northeast presents itself as an alternative to counter the effects of crises in the traditional activities of the agricultural sector. Based on this premise the Government of the State of Sergipe implemented in the eighties many irrigated areas, to develop the semi-arid region, in order to increase the quality of life for residents by building on agricultural potential demonstrated by the climate, soil and availability of water for irrigation. owever, these projects have failed the success planned for various reasons. Thus, this study aims to analyze the dynamics of water, agricultural production and the profile of irrigation irrigated perimeter California, located in Canindé municipalities de San Francisco and Poço Redondo, in the extreme northwest of the state, in the semi-arid northeast. For this, there were literature surveys, desk reviews, structured interviews with questionnaires to the technical audience of local administration and the irrigators, seeking information about the type of agricultural production, social, economic and environmental. Research shows that driving the water meets technical problems especially in pumping stations resulting in lack of water for irrigation of agricultural crops. Agricultural production is shown to be diverse, but with concentration in Okra culture that predominates in most lots, to have guaranteed market. Technical assistance is cause for dissatisfaction, pointing in field research. The profile of irrigation shows that most settled in the region since the 2000s, and had cultural tradition in the primary sector of the economy also points out that between the social measures adopted, the family allowance is an important public policy and local visibility. hese considerations point to the need to problematize the development policies of the semi-arid northeast, especially the actions aimed at improving irrigated areas. / A irrigação no Nordeste apresenta-se como alternativa para contrapor aos efeitos das crises nas atividades tradicionais do setor agrário. Baseado nesta premissa o Governo do Estado de Sergipe implantou na década de oitenta diversos perímetros irrigados, visando o desenvolvimento da região semiárida, com o intuito de aumentar a qualidade de vida dos habitantes mediante o aproveitamento do potencial agrícola demonstrado pelo clima, solo e disponibilidade de água para a irrigação. Não obstante, estes projetos não lograram o êxito planejado, por razões diversas. Desta forma, este trabalho tem como objetivo analisar o perfil social e a produção agrícola do perímetro irrigado Califórnia, localizado nos municípios de Canindé do São Francisco e Poço Redondo, no extremo noroeste do Estado, no semiárido nordestino. Para isto, realizaram-se levantamentos bibliográficos, análises documentais, entrevistas semiestruturadas com aplicação de questionários ao público técnico da administração local e a irrigantes, buscando informações sobre o tipo de produção agrícola, aspectos sociais, econômicos e ambientais. A pesquisa mostra que condução da água encontra-se com problemas técnicos especialmente nas estações elevatórias acarretando na falta de água para irrigação das culturas agrícolas. A produção agrícola mostra-se diversificada, mas com concentração na cultura do quiabo, que predomina na maioria dos lotes, por ter mercado garantido. A assistência técnica é motivo de insatisfação, apontada na pesquisa de campo. O perfil dos irrigantes evidencia que a maior parte fixou-se na região a partir dos anos 2000, e tinham tradição cultural no setor primário da economia, além disso, aponta que entre as medidas sociais adotadas, a bolsa família é uma política pública importante e de visibilidade local. Tais considerações apontam para a necessidade de problematizar as políticas desenvolvimentistas do semiárido nordestino, especialmente as ações direcionadas a melhoria dos perímetros irrigados.

Le Norte-Chico constitue une zone tampon ayant enregistrée les fluctuations climatiques quaternaires. La fraîcheur des modelés et des formes présents dans la haute cordillère de l’Elqui, va nous permettre de tenter d’expliquer le calendrier de mise en place des éléments du relief. Les indices de terrain nous permettent de mettre en évidence un enchaînement de processus faisant intervenir la notion de relais et de zones tampons dans le transit sédimentaire. Les crises morphogéniques à l’origine des formations de versant et de fond de vallée actuellement visibles résultent d’une réponse plus ou moins directe de l’orogène Andin aux épisodes climatiques ; par conséquent, les résultats obtenus sont confrontés aux résultats d’autres études et dans des sites proches ou non de notre lieu d’étude afin d’apporter des exemples et des arguments aux hypothèses actuelles sur l’évolution des conditions climatiques quaternaires du Norte-Chico. La complexité de la mise en place des éléments du relief nécessite en premier lieu une explication des différentes phases orogéniques ainsi que des évolutions morphoclimatiques ayant abouti à la mise en place des conditions actuelles. Ensuite, la méthodologie nécessaire au travail de terrain et à l’obtention de résultats cohérents est définie et expliquée. Une dernière partie est consacrée à la synthèse de l’enchaînement de mise en place des formations de fond de vallée ; les résultats de cette étude sont également replacés dans un débat scientifique plus large permettant d’appréhender les potentialités apportées par la géomorphologie dans l’étude des paléoenvironnements quaternaires dans le Norte-Chico comme à l’échelle planétaire. / Norte Chico is a buffer zone having registered Quaternary climatic fluctuations. The preservation of landforms and relief present in the Elqui cordillera, make it a rich geomorphological study area, which may provide answers to many of the assumptions Quaternary calendar climate of the region. Freshness and modeled forms present in the high Andes of Elqui, coupled with the presence of datable organic matter, will allow us to to explain the timing of implementation of the elements of relief. Field indices surveys allow us to highlight a series of processes involving the notion of relay and buffer zones in the sediment transport. Morphogenic crises originally training slope and valley floor currently visible result of a more or less direct answer of the Andean orogen to climatic events, so the results are compared with the results of other studies and in sites close or not our place of study to provide examples and arguments to current hypotheses on the evolution of the Quaternary climatic Norte Chico and multiscale way. The complexity of the implementation of the relief units, requires firstly an explanation of the different orogenic phases and developments morphoclimatic leading to the gradual development of current conditions. Second, the methodology necessary fieldwork and consistent results is defined and explained. A final section presents the synthesis of the series of training implementation valley bottom; the results of this study are also viewed in a broader scientific debate to apprehend the potential provided by the geomorphology in the Quaternary paleoenvironmental study of the Norte Chico as globally.

Le nord du Chili est soumis à un contexte climatique aride à semi-aride présentant une variabilité saisonnière et inter-annuelle forte. Dans cette région les zones de haute altitude soutiennent les parties plus basses des bassins versants, mais la ressource en eau reste malgré tout limitée. Afin d'améliorer les méthodes de gestion de l'eau dans ces bassins versants, il est important de préciser le rôle des zones de haute altitude dans le soutien des parties basses, mais aussi de caractériser les modalités de transfert et d'interaction entre les compartiments constitutifs de l'hydrosystème. Ce travail porte sur la caractérisation du fonctionnement hydrologique du bassin versant de l'Elqui depuis la tête de bassin, située au cœur de la cordillère des Andes, jusqu'aux vallées de la zone inférieure situées entre 500 et 2000 mètres d'altitude. En tête de bassin, les processus d'interaction entre les compartiments cryosphériques, hydrologiques et hydrogéologiques, et leurs impacts sur le transfert des masses d'eau vers l'aval de la zone d'étude sont caractérisés. Le comportement hydrologique des sous bassins versant partiellement ou non‑englacés est également étudié. Dans la zone inférieure du bassin, l'étude porte principalement sur les processus d'interactions surface-souterrain en contexte semi‑aride et sur les impacts des forçages climatiques et anthropiques sur ces derniers. Cette étude s'appuie sur plus de 40 ans de données hydro-météorologiques disponibles sur la zone inférieure du bassin, complétés par des mesures hydrologiques sur la zone supérieure (> 2000 mètres d'altitude) et des prélèvements chimiques (majeurs et traces) et isotopiques (²D, 18O) sur la totalité de la zone d'étude, réalisés entre 2011 et 2013.Ces travaux ont montré que le modèle conceptuel de fonctionnement du bassin versant de l'Elqui généralement accepté était incomplet. Dans la zone supérieure, l'étude d'un bassin versant englacé a permis de montrer que le rôle de la cryosphère dépasse la fonction de production d'eau, avec certains compartiments stockant temporairement de l'eau en période humide et la libérant en période sèche. Ce processus permet d'amortir la variabilité temporelle des précipitations et du taux de fonte en altitude. Les analyses physico-chimiques réalisées dans le bassin versant ont également permis d'identifier des compartiments aquifères ignorés jusqu'à maintenant, comme les compartiments volcanique et plutonique. En améliorant les connaissances sur les processus d'interactions entre compartiments cryosphériques, hydrologiques et hydrogéologiques, les résultats de ce travail ont apporté des précisions sur le fonctionnement hydrologique de la zone de haute altitude. Cela a permis l'estimation des impacts potentiels de la variabilité climatique sur ces processus d'interactions et leurs conséquences sur la disponibilité et la qualité de la ressource. Dans la zone inférieure, la caractérisation des interactions surface-souterrain a montré qu'il existe un fort potentiel d'interaction entre le compartiment hydrologique et le compartiment alluvial, mais également entre le compartiment alluvial et le socle plutonique. L'étude des données hydrologiques et physico-chimiques a permis de caractériser le type d'échanges se déroulant entre les compartiments. Dans certains secteurs le processus dominant est la recharge du compartiment alluvial par le compartiment hydrologique, tandis que pour d'autres il existe une alternance entre période de drainage du compartiment alluvial par le compartiment hydrologique et période de recharge du compartiment alluvial. La réponse de ces processus face aux impacts des forçages climatiques et anthropiques contraindra la disponibilité et la qualité de la ressource dans les années à venir. Ainsi, les résultats apportés par ce travail permettront certainement de mieux anticiper les modifications futures du fonctionnement hydrologique des bassins versant montagneux en contexte semi-arides. / The north Chile is affected by an arid to semi-arid climate, associated with a strong seasonal to inter-annual variability. In this region, while mountainous areas are supporting low areas, the availability of water resources remains limited. In order to improve the water management in these basins, it is necessary to precise how the high areas support the low areas, and to characterize water transfers and interaction processes between the constitutive compartments of the hydrosystem. This work concern the characterization of the hydrodynamic behavior of the Elqui watershed from the headwaters, in the Andes, to the valleys, ranging between 500 and 2000 m.a.s.l.In the headwaters, the interactions processes between cryospheric and hydrologic compartments and their impact on water transfers to the low areas are characterized. The behavior of unglacierized or partially glacierized watershed is also studied. In the low area of the watershed, the study mainly considers groundwater-surface water interactions under semi-arid context and the impact of the climatic variability on these processes. This study is based on more than 40 years of hydro-meteorological data available in the lower zone of the basin, completed by hydrological measurements in the upper zone (> 2000 m.a.s.l.) and chemical (majors and traces elements) and isotopic samples (²D, 18O) over the whole study area realized between 2011 and 2013.This work demonstrated that the conceptual model of the Elqui basin hydrological behavior, generally accepted, was incomplete. In the high area (> 2000 m.a.s.l.), the study of a glacierized watershed show that the function of the cryosphere overpass the water production with some compartments storing water during humid periods and draining their water content during dry periods. This process buffers the temporal variability of precipitations and melting rates in the high area. Physico-chemical analysis, allows to identify some ignored aquifer compartments, as the volcanic and plutonic compartments. The results of this study improve the knowledge about interactions processes between cryospheric, hydrologic and hydrogeologic compartments, which precise the hydrological functioning of the high area. The interpretation of the hydrological behavior of the high altitude area allows to better understand the way that it support the low area, and the way that climate variability may affects it.In the low area, results show that the groundwater-surface water interaction potential is good between alluvial and hydrological compartments, but also between the plutonic and the alluvial compartments. The study of hydro-meteorological and physico-chemical data allowed to characterize the type of exchanges that take place between groundwater and surface water. In some sectors the main process is the recharge of the alluvial compartment by the hydrological compartment, while in other sectors the processes show a seasonal variability with periods of alluvial compartment recharge and periods of hydrological compartment support. The answer of these processes face to climatic and anthropic forcing will constrain the evolution of the availability and quality of the water resources in the Elqui basin. Finally, the results of this study will certainly allow to better anticipate the future modifications of the semi-arid mountainous watershed hydrological functioning.

The Permo-Triassic lower Beaufort Group fluvial deposits extend over 100s of kilometres within the Karoo Basin, South Africa. A detailed study of the depositional architecture and stacking patterns of sand bodies within a 900 m thick succession has enabled interpretation of the controls on ancient river channel and overbank processes. Facies include very fine- to medium-grained sandstone, intra-formational conglomerate, mudstone and palaeosols. Channel-belts are dominated by upper flow regime structures, consistent with a flashy to ephemeral fluvial system. The overbank deposits comprise splays interbedded with purple, green and grey mudstone; these floodplain colour changes signify water table fluctuations. A hierarchy of channel-related elements has been established that recognises beds, bedsets, storeys, channel-belts, complexes and complex sets. Each channel-belt may be single- or multi-storey, whereby one storey represents the complete cut and fill cycle of a single migrating river, comprising bar accretion elements and channel-abandonment fill. The abandonment fill elements often consist of heterolithic plugs of climbing ripple-laminated very fine-grained sandstone, or interbedded claystone with siltstone. The Beaufort channel-belts preserve either lateral- or downstream-accretion patterns, or a combination. Each belt has either a lenticular or tabular geometry, recognisable by an erosional base overlain by intra-formational conglomerate lag and barform deposits. Genetically related channel-belts cluster to form complexes, of which two broad styles have been identified: Type A) laterally and vertically stacked channel-belts, and Type B) sub-vertically stacked channel-belts. There is evidence of localised clustering of sub-vertically stacked channel-belts adjacent to extensive overbank mudstone deposits. The apparent lack of a well-defined ‘container’ surface with mappable margins, suggests that this stacked channel-belt architecture represents an avulsion complex rather than a palaeovalley-fill. The lateral and stratigraphic variability in fluvial-overbank architecture is interpreted as the interplay of several controls. Allogenic forcing factors include, tectonic subsidence that influences accommodation, sediment supply, and high frequency climate cycles associated with the flashy discharge regime and expressed in the mudrock colour changes and distribution of palaeosols. The depositional river style, variability in channel-belt stacking patterns and compensational stacking of some channel-belt/splay complexes is interpreted to be the result of autogenic channel avulsion, supported by an absence of significant erosion. The relative merits of basin-axial trunk river and distributive fluvial system (DFS) models are assessed from detailed architectural and stratigraphic outcrop studies.

Los corredores riparios en ambientes semiáridos mediterráneos son ecosistemas de gran biodiversidad y complejidad. En ellos confluyen una gran variedad de perturbaciones naturales capaces de crear un mosaico espacial y temporal con pocos paralelos en otros ecosistemas. Sin embargo, a pesar de su valor, los ecosistemas riparios están amenazados debido a los altos niveles de intervención humana. La construcción de presas (y la consecuente manipulación del caudal) está considerada como la perturbación humana más importante que se cierne sobre ellos. Esta tesis ha tenido como objetivo analizar el ecosistema ripario, abarcando diferentes escalas espaciales y temporales, y centrándose en los factores que influyen en la distribución, estructura, composición, calidad y dinámica de su vegetación, tanto en tramos naturales como hidrológicamente alterados de ríos mediterráneos, concretamente de la Demarcación Hidrográfica del Júcar (Este de España). Para lograr este objetivo, se han hecho los siguientes aportes a la investigación: A) Determinar los patrones de distribución de especies leñosas riparias en el gradiente transversal de la ribera y definir grupos de especies con respuesta similar a las condiciones físicas del hábitat; B) Comparar la respuesta de dichas especies en tramos naturales y alterados hidrológicamente; C) Definir curvas de respuesta y gremios hidrológicos de especies en tramos con régimen natural; D) Establecer los principales factores que determinan la calidad del hábitat ripario y fluvial y los patrones longitudinales de la composición florística, así como de las características del hábitat fluvial en un segmento hidrológicamente alterado; E) Describir los cambios espacio-temporales en la estructura y complejidad de la vegetación, y los cambios temporales en el régimen de caudales del corredor ripario de un tramo hidrológicamente alterado. Los objetivos anteriores fueron abordados con diferentes metodologías que implicaron la combinación de diversas fuentes de información y un esfuerzo importante en la toma de datos en varios lugares de estudio de los ríos Cabriel, Mijares y Serpis. Para cumplir con los objetivos A y B, se llevaron a cabo un muestreo de suelos y un muestreo georreferenciado de vegetación a través de transectos transversales al cauce en dos tramos naturales y tres regulados. Los datos fueron analizados con estadística robusta y multivariante. Para cumplir el objetivo C, el muestreo georreferenciado anterior (junto con un muestreo dendrocronológico) fue acoplado con un modelo hidráulico en los dos tramos naturales, con el fin de obtener la serie temporal de cotas del agua a la que habían estado expuestas cada una de las plantas durante su vida. La respuesta de las especies y su posible agregación en gremios hidrológicos fue comparada mediante estadística robusta en relación a la duración de la inundación, duración de la inundación durante el período de crecimiento, duración continua de la inundación, frecuencia de inundación y elevación de la planta respecto al caudal base. Para lograr el objetivo D, toda la sección regulada del río Serpis (desde la presa Beniarrés - hasta la desembocadura; 40 km) se dividió en segmentos. En cada uno de ellos se llevó a cabo un inventario de flora y se aplicaron índices hidromorfológicos. Los segmentos fueron agrupados de acuerdo a su composición florística y características del hábitat fluvial utilizando diferentes técnicas de estadística multivariante. Finalmente se discutieron los factores principales que controlan los patrones espaciales de la composición florística, las características del hábitat fluvial, la calidad del hábitat ribereño y la heterogeneidad del hábitat fluvial. Para alcanzar el objetivo E, se combinaron series históricas de caudales y su manipulación humana con imágenes aéreas históricas (reveladoras de cambios en la cubierta vegetal) y observaciones de campo de la distribución de edades de la vegetación y morfología del corredor ripario del río Mijares en los últimos 60 años. De esta información, se extrajeron métricas del paisaje e índices hidrológicos para identificar y resumir los cambios espacio-temporales en la estructura de la ribera y en el régimen de caudales. El estudio a escala transversal nos ayudó a comprender en cada uno de los tramos la zonación de las especies leñosas riparias en función de la morfología y características del suelo, revelando que la alteración del caudal puede influir en la modificación de los patrones posicionales de las especies. Se definieron tres gremios hidrológicos: ¿altamente tolerante a la inundación¿, ¿tolerante intermedio¿ y ¿de transición entre ripario y terrestre¿. El estudio a escala longitudinal sugirió que la respuesta de la vegetación a un cambio hidrológico es altamente dependiente de la geomorfología local. Se constató que los factores principales que determinan los patrones hidromorfológicos y florísticos son un régimen de caudales artificial y altamente variable (identificado en los segmentos con peor calidad del hábitat ripario y fluvial), la presencia de estructuras laterales en el cauce y las características geomorfológicas. Como efectos importantes de la regulación del caudal a largo plazo, el estudio a escala espacio-temporal reveló un aumento en la cobertura y densidad de la vegetación leñosa, una deriva en la composición de especies y una disminución en las áreas de sedimento desnudo (esencial para el reclutamiento de las especies riparias pioneras), junto con una reducción sincrónica en la complejidad de la ribera. Estos cambios estarían relacionados con la disminución de la magnitud y variabilidad de los caudales en las últimas seis décadas. Solo una mejor comprensión de los procesos ecohidrológicos y de las implicaciones de la alteración hidrológica sobre los ecosistemas riparios mediterráneos podrá apoyar la integración eficaz de estos sistemas en las decisiones de gestión del agua. / Garófano Gómez, V. (2013). Riparian vegetation patterns according to hydrogeomorphological factors at different spatial and temporal scales in Mediterranean rivers [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/29395 / TESIS