Dissertations / Theses on the topic 'Grandes Plaines'

La zone hyporhéique est un bioréacteur pouvant influencer le fonctionnement biogéochimique des hydrosystèmes fluviaux. La quantification de son rôle vis-à-vis des flux d'eau et d'éléments dissous transitant dans l'hydrosystème de grande plaine alluviale a été réalisée par modélisation numérique. Le travail de modélisation s'appuie sur des données précédemment acquises sur les sites expérimentaux de Freienbrink (Allemagne), de l'Hers et de la Garonne (France). La démarche de modélisation a consisté à développer un modèle hydrodynamique couplant les équations de Saint Venant (2D) pour les écoulements de surface et les équations de Darcy-Dupuit pour le milieu poreux, ainsi qu'un modèle de transport réactif des formes dissoutes de l'azote minéral et de la matière organique. L'ensemble des conclusions souligne l'importance des échanges transitoires entre cours d'eau et zone hyporhéique qui favorisent le stockage de l'eau et l'activation des processus de dénitrification
The hyporheic zone is a bioreactor which can influence the biogeochemical functioning of fluvial hydrosystems. In this work, quantification of its role on water and solutes fluxes in hydrosystem of large alluvial floodplains was made by modelling approach. The proposed model was applied and validated using data previously measured on experimental sites of Freienbrink (Germany), Hers and Garonne (France). The complete model consists of two additional components: a hydrodynamic component (horizontal 2D Saint Venant equations for river flow and 2D Dupuit equations for hyporheic zone flow) coupled with a reactive solute-transport component for dissolved forms of mineral nitrogen and organic matter. The conclusions highlight the importance of transient exchanges between stream and hyporheic zone which facilitate water storage and denitrification processes activation

Les Européens attirés par les richesses de l'extrême orient, vulgarisées par les croisades, accessibles par la route de la soie ouverte par les Mongols, veulent se soustraire à la rapacité des caravaniers. Par Le Cap, Vasco de Gama mène le Portugal à l'Orient, et Magellan y guide les Espagnols en contournant l'Amérique du Sud. Anglais et Hollandais cherchent la route du Nord-Ouest. Les Français songent à une voie transcontinentale par "la Rivière de l'Ouest" et "la Mer de l'Ouest" entrevue par Verrazzano, tracée par des géographes dont Delisle. Cartier découvre le Saint-Laurent, Champlain prolonge jusqu'aux Grands Lacs. Sollicité par Lewis Cass, Margry distingue Pierre de La Vérendrye (1685-1749). Margry est surpris par cet audacieux personnage entraînant sa famille à la recherche de la "Mer de l'Ouest" ; renseigné par les Indiens et la carte d'Auchagah gravée par Chaussegros ; créant des postes du lac Supérieur au lac Manitoba, et à la Saskatchewan, génant la traite anglo-indienne à la Baie d'Hudson ; découvrant le réseau hydrographique du lac Winnipeg et des lacs adjacents, avec les rivières Winnipic, Saskatchewan, Rouge du Nord, son affluent l'Assiniboine, grossie de la Qu'Appelle et la Souris menant au Missouri, et chez les Mandans peints par Catlin ou vers les Bighorn. Il le voit subir avec constance les pires épreuves : dénigrement, mésestime du ministre, décès de son neveu, massacre du fils aîné et du Père Aulneau. Destitué, puis nommé capitaine et chevalier de Saint-Louis, rétabli commandant à la "Mer de l'Ouest", il obtient enfin la reconnaissance de ses qualités exceptionnelles. Il est admis par les historiens comme l'égal des Cartier, Champlain, Mackenzie, Lewis et Clark
Attrated by Far Eastern luxury reachable through the silk road open by the Mongols, Europeans wished to escape from greedy caravaneers. Vasco de Gama reached the Far East round the Cape of Good Hope, and Magellan reached it surrounding South America. The Dutch and The English sought the North-West road. The French thought about a transcontinental water way throught the "River of the West" and the "Western Sea", of which Verrazzano caught a glimpse, drawn by geographers among them Delisle. Cartier discovered the Saint-Lawrence River, Champlain extented the water way to the Great Lakes. Margry noticed Pierre de La Vérendrye (1685-1749) at the request of Lewis Cass. Margry was astonished by this bold man who dragged his family toward the "Western Sea", under informations picked of from Indians and from the map of Auchagah redrawn by Chaussegros ; building posts from Lake Superior to Lake Superior to Lake Manitoba, and on the Saskatchewan River, putting obstacles upon the Hudson Bay Indian's trade ; discovering the hydrographical net work of Lake Winnipeg and adjacent lakes, with rivers : Winnipic, Saskatchewan, Red from the North and its Assiniboin tributary swelled by the Qu'Appel and The Souris, which led to the Missouri River and the Mandans, and even to the Bighorn. He saw him suffer the worst hardships : defamation, little regards from his Minister, death of his nephew, and his first son and Father Aulneau slaughtered by the Sioux. After he was discharged, his appointement as captain and chevalier of the Saint-Louis Cross, and his restoration has commander to the "Western Sea" post, show recognition for his outstandingly gifted qualities. Historians consider him equal to : Champlain, Lewis and Clark. . .

This dissertation is a study of the Eastern Apache nations and their struggle to survive with their culture intact against numerous enemies intent on destroying them. It is a synthesis of published secondary and primary materials, supported with archival materials, primarily from the Béxar Archives. The Apaches living on the plains have suffered from a lack of a good comprehensive study, even though they played an important role in hindering Spanish expansion in the American Southwest. When the Spanish first encountered the Apaches they were living peacefully on the plains, although they occasionally raided nearby tribes. When the Spanish began settling in the Southwest they changed the dynamics of the region by introducing horses. The Apaches quickly adopted the animals into their culture and used them to dominate their neighbors. Apache power declined in the eighteenth century when their Caddoan enemies acquired guns from the French, and the powerful Comanches gained access to horses and began invading northern Apache territory. Surrounded by enemies, the Apaches increasingly turned to the Spanish for aid and protection rather than trade. The Spanish-Apache peace was fraught with problems. The Spaniards tended to lump all Apaches into one group even though, in reality, each band operated independently. Thus, when one Apache band raided a Spanish outpost, the Spanish considered the peace broken. On the other hand, since Apaches considered each Spanish settlement a distinct "band" they saw nothing wrong in making peace at one Spanish location while continuing to raid another. Eventually the Spanish encouraged other Indians tribes to launch a campaign of unrelenting war against the Apaches. Despite devastating attacks from their enemies, the Apaches were able to survive. When the Mexican Revolution removed the Spanish from the area, the Apaches remained and still occupied portions of the plains as late as the 1870s. Despite the pressures brought to bear upon them the Apaches prevailed, retaining their freedoms longer than almost any other tribe.

La vision du monde rural du haut Moyen Age a été profondément modifiée durant ces dernières décennies grâce à l'archéologie préventive. Les grands travaux d'aménagement franciliens depuis les années 1980 ont offert l'occasion de fouiller de nombreux sites d'habitat avec plusieurs étapes dans cette exploration et un changement d'échelle dans les ouvertures. Jusqu'à cette période, les rares exemples d'habitats connus avaient nourri une vision pessimiste des historiens tels Georges Duby et Robert Fossier (Nissen sous presse) sur les conditions de vie et des pratiques agricoles durant le haut Moyen Age
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Cette thèse entend éclairer la relation étroite qui existe entre la nature éminemment littéraire des poèmes de circonstance et leur dimension politique. En analysant l'oeuvre de 1565 qui n'a jamais fait l'objet d'une étude exclusive. [. . . ]La première partie présente une reconstitution des fêtes et décèle une tension créée chez Ronsard par l'obligation de rester anonyme, tout en s'efforçant de garder indépendante son inspiration poétique. [. . . ]La deuxième partie traite de la "politique de dédicace" qui permet au poète à la fois d'exprimer l'entente cordiale souhaitée par Catherine de Médicis et de conserver son autonomie créatrice marquée par son attitude modeste, réservée et prudente. Enfin, la troisième partie analyse les thèmes traditionnels de la fête et montre la réticence du poète vis-à-vis de la thèse de la transcendance. [. . . ]Loin d'être le signe de la servilité de Ronsard, cette oeuvre destinée au service de la politique présente un poète habile, capable de faire coi͏̈ncider ses idées poètiques avec l'intérêt devenu la matière de sa poèsie.

Mise en parallele des recits hagiographiques en vers (passions et biographies) composes par des clercs en angleterre aux xiie et xiiie siecles, avec les textes latins dont les hagiographes se sont inspires. L'objet de la these est de relever comment les oeuvres vernaculaires ont put s'adapter aux gouts, aux aspirations d'un auditoire laic ignorant de la lettre latine que les auteurs devaient edifier, mais aussi interesser, votre seduire. Ainsi ont ete mesurees la nature et la fonction des modifications apportees par les auteurs vernaculaires, et on a pu juger d'une possible influence et de la litterature religieuse anterieure (chansons de saints du xie siecle), et surtout de la litterature profane (chanson de geste et roman), tant pour ce qui est du mode de performance des oeuvres que de la composition de celles-ci. Cette recherche est menee sur un corpus de vingt-quatre textes, et plus particulierement sur la vie de saint gilles composee par guillaume de berneville, dont l'etude fait l'objet de la derniere partie de la these
Comparaison of hagiographic stories in verse (passions and biographies) compsed by clerics in england in the xii th and xiii th centuries, with the latin texts xhich by the hagiographers had been inspired. The subject of the thesis is to study how vernacular texts had been adapted to the tastes and aspirations of a secular audience that does not know the latin authorities. The authors and to edify, but also interest and fascinate that public. The objective is to mesure the nature and the function of the modifications, and to judge a possible influence of the former religious litterature (saints'liv es of xi th), and specially of litterature (epic and romantic), as regards the performance and the composition of the texts. The coprus includes 24 textes, and the study is specially about st gilles life by guillaume de berneville

Dans certains phénomènes physiques modélisés par des EDP, les coefficients intervenant dans les équations ne sont pas des fonctions déterministes fixées, et dépendent de paramètres qui peuvent varier. Ceci se produit par exemple dans le cadre de la modélisation des écoulements en milieu poreux lorsqu’on décrit le champ de perméabilité par un processus stochastique pour tenir compte de l’incertitude sur ce champs. Dans d’autres cadres, il peut s’agir de paramètres déterministes que l’on cherche à ajuster, par exemple pour optimiser un certain critère sur la solution. La solution u dépend donc non seulement de la variable x d’espace/temps mais aussi d’un vecteur y = (yj) de paramètres potentiellement nombreux, voire en nombre infinis. L’approximation numérique en y de l’application (x,y)-> u(x, y) est donc impossible par les méthodes classiques de type éléments finis, et il faut envisager des approches adaptées aux grandes dimensions. Cette thèse est consacrée à l’étude théorique et l’approximation numérique des EDP paramétriques en grandes dimensions. Pour une large classe d’EDP avec une certaine dépendance anisotrope en les paramètres yj, on étudie de la régularité en y de l’application u et on propose des méthodes d’approximation numérique dont les performances ne subissent pas les détériorations classiquement observées en grande dimension. On cherche en particulier à évaluer la complexité de la classe des solutions {u(y)}, par exemple au sens des épaisseurs de Kolmogorov, afin de comprendre les limites inhérentes des méthodes numériques. On analyse en pratique les propriétés de convergences de diverses méthodes d’approximation avec des polynômes creux
For certain physical phenomenon that are modelled by PDE, the coefficients intervening in the equations are not fixed deterministic functions, but depend on parameters that may vary

Il est désormais bien reconnu que les activités agricoles sont à l'origine d'une grande part de la pollution des nappes souterraines par les ions nitrate. Le cas des plaines alluviales est particulièrement intéressant puisqu'elles associent la présence d'un sol riche et profond, très favorable à l'agriculture, et d'une nappe alluviale peu profonde. Dans ce travail nous nous sommes intéressés à deux types de plaine alluviale. La plaine alluviale de la rivière Alegria (Pays-Basque ; Espagne) représente le cas d'une nappe alluviale avec un cours d'eau de faible importance. La recharge de l'aquifère se fait alors principalement par l'infiltration et la percolation de l'eau à travers la zone non saturée du sol. Dans une telle situation les fuites de nitrate sous les parcelles agricoles influencent donc significativement les concentrations en nitrate de la nappe. La modélisation de deux situations culturales (une culture de pommes de terre en 1993 et une culture de betteraves à sucre en 2002) avec le modèle de culture STICS a permis d'une part de confirmer que les pratiques agricoles avaient un impact significatif sur l'évolution des concentrations en nitrate de la nappe, et d'autre part d'expliquer en partie la diminution des concentrations en nitrate de la nappe qui a été observé entre les études (1993 et 2002). La plaine alluviale de la Garonne correspond à une situation ou les concentrations en solutés de la nappe sont influencées par les échanges nappe-zone non saturée mais également par les échanges nappe-rivière. Le couplage des sorties du modèle STICS (drainage et concentration en nitrate) avec le modèle hydro-biogéochimique 2SWEM a permis de rendre compte de ces deux types d'interactions, et ainsi d'une part d'expliquer la répartition spatiale des concentrations en nitrate dans la nappe alluviale, et d'autre part d'évaluer l'impact de modifications des pratiques agricoles sur ces concentrations (notamment l'effet des Cultures Intermédiaires Piège À Nitrate)
It is now, well recognized that agricultural activities are responsible for an important part of the groundwater nitrate pollution. The case of the alluvial plains is particularly interesting because they associate the presence of a rich and deep soil, very favourable to the agriculture, and shallow alluvial groundwater. In this work we are interested in two types of alluvial plain. The alluvial plain of the Alegria River (Pays-Basque, Spain) represent the case of an alluvial plain with a small river. The recharge of the aquifer is mainly made by the infiltration and the percolation of the water through the not saturated zone of the soil. In such situation the nitrate leaching under the agricultural plots influences significantly the groundwater nitrate concentrations. The modelling of two crops (a potato crop in 1993 and a sugar beet crop in 2002) with the model the STICS soil-crop allowed on one hand to confirm that the agricultural practices had a significant impact on the evolution of the groundwater nitrate concentrations, and on the other hand to explain partially the decrease of the concentrations which was observed between the studies (between 1993 and 2002). The alluvial plain of the Garonne corresponds to a situation where the groundwater solutes concentrations are influenced by the exchanges between not saturated zone and the groundwater but also by the exchanges between groundwater and river. The coupling of the STICS model outputs (drainage and concentration in nitrate) with the hydro-biogeochemical model 2SWEM allowed to simulate these two types of interactions, and so, on one hand to explain the spatial distribution of the groundwater nitrate concentrations, and on the other hand to estimate the impact of modifications of the agricultural practices on these concentrations (notably the effect of the catch crop)

Cette thèse se fonde sur une étude qualitative et comparative menée dans deux TPE de moins de 10 salariés et deux GE de plus de 5 000 salariés. L’objectif est de comprendre et d’expliquer, d’une part, comment se construit le stress professionnel selon la taille de l’entreprise et, d’autre part, les moteurs ou les freins à la prévention et gestion du stress. Je me suis donc intéressée aux représentations socio-professionnelles du stress, aux relations sociales au sein de l’entreprise, à l’expression ou non de la plainte, aux formes de gestion de toute forme de souffrance qui peut être liée au travail, à la régulation des conflits. Les attentes collectives ou individuelles ainsi que le vécu des acteurs confrontés à des réalités similaires mais qui réagissent différemment ont aussi permis de tirer des enseignements sur le rapport au mal-être. Cette recherche a montré que, contrairement à ce que l’on pourrait penser, ce ne sont pas tant les problématiques à gérer qui différent en fonction de la taille de l’entreprise mais les façons de les construire, de les vivre et de les réguler
This thesis is based on a qualitative and comparative study carried out in two Very smallbusinesses (less than ten (10) employees) and two Big businesses (more than five thousand(5.000) employees). The objective is to understand and explain, on the one hand, howprofessional stress is built up according to the size of the company and, on the other hand, thedrivers or constraints to the prevention and management of stress in businesses. I have therefore been interested in socio-professional representations of stress, social relations withinthe company and the expression or not of grievance. I also study forms of pain management atwork and conflicts regulation. Analyzing collective and individual expectations as well as thelife stories of workers confronted with similar realities but reacting differently, made itpossible to learn lessons about workers relationship to discontent.This research has shown that, contrary to what one might think, it is not so much the problemsto be managed which differ according to the business size but the ways to build, regulate andlive with these issues

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior
The research conducted in Barra Grande, Icapuà â CE analyzed in a systematic way the geo environmental aspects of Barra Grande estuary with emphasis on mangrove and other coastal systems associated with it. The methodological foundations were related to the definition of the dynamic processes by identifying flows of matter and energy of the geo environmental diagnosis to highlight the importance of the mangrove estuary and in the maintenance of other coastal ecosystems and biodiversity. In this process, a space-time analysis was made through the preparation of thematic maps and charts showing the occupation of mangrove by economic activities generating impacts (salt, fish and shrimp) that led to environmental degradation and impairment of the ecosystem and its biodiversity. We also analyzed the social mobilization initiatives and environmental education process that arose from the joints of youth groups and NGOs that triggered political and environmental movements in Icapuà generators of change of attitude toward the use and conservation of mangroves. Also noteworthy is the implementation of projects for the rehabilitation of degraded areas and conservation of the wetland, identified and analyzed to provide data for interpreting the potential for social mobilization for the conservation of lowland environmental systems under study. Finally, the research allowed the development of a proposed environmental zoning of the estuary and mangrove swamp, with reference to the demarcation proposed by the Municipal Law No. 298/2000 which established the Environmental Protection Area (EPA) of Barra Grande
A pesquisa realizada na Barra Grande no municÃpio de IcapuÃ-CE, analisou deforma sistÃmica os aspectos geoambientais do estuÃrio Barra Grande com Ãnfase no manguezal e os demais sistemas costeiros associados. Os fundamentos metodolÃgicos foram relacionados com a definiÃÃo dos processos dinÃmicos atravÃs da identificaÃÃo dos fluxos de matÃria e energia do diagnÃstico geoambiental para evidenciar a importÃncia do estuÃrio e do manguezal na manutenÃÃo dos demais ecossistemas costeiros e da biodiversidade. Neste processo, fez-se a anÃlise espaÃo-temporal atravÃs da elaboraÃÃo de mapas e cartas temÃticas evidenciando a ocupaÃÃo do manguezal por atividades econÃmicas geradores de impactos (salinas, pesca e carcinicultura) que levaram à degradaÃÃo ambiental e ao comprometimento do ecossistema e sua biodiversidade. TambÃm foram analisadas as iniciativas de mobilizaÃÃo social e do processo de educaÃÃo ambiental que surgiram de articulaÃÃes de grupos de jovens e ONG que desencadearam movimentos ambientalistas e polÃticos em Icapuà geradores da mudanÃa de atitude diante dos usos e preservaÃÃo do manguezal. Destaca-se tambÃm a implantaÃÃo de projetos voltados para a recuperaÃÃo das Ãreas degradadas e conservaÃÃo do manguezal, identificados e analisados de modo a fornecerem dados para interpretar o potencial social de mobilizaÃÃo para a conservaÃÃo dos sistemas ambientais da planÃcie em estudo. Por fim, a pesquisa possibilitou a elaboraÃÃo de uma proposta de zoneamento ambiental do estuÃrio e manguezal, tendo como referÃncia a demarcaÃÃo proposta pela Lei Municipal N 298/2000 que criou a Ãrea de ProteÃÃo Ambiental (APA) da Barra Grande.

O conhecimento das estruturas, feições e formas numa bacia de drenagem é parte integrante do reconhecimento de sua evolução e dinâmica. Abordando a avaliação geomorfológica e dinâmica, destacamos todos os fatores físicos ambientais inerentes aos processos de formação das estruturas e feições. O presente trabalho tem como objetivo principal propor uma caracterização morfométrica da microbacia do arroio Chuí a partir da identificação do divisor de águas adjacente ao arroio Pastoreio, na região sul do estado do Rio Grande do Sul. A identificação da nascente do arroio, foi realizada preliminarmente pela análise em imagens do satélite Landsat 5 sensor TM do ano 2009 associado a dados do modelo digital de elevação (SRTM), sendo posteriormente identificado por observações em campo. Em campo, foi realizado levantamento topográfico na região do divisor de águas com a finalidade de melhor caracterização das suaves variações morfológicas da área. Em laboratório, foram processados e refinados os dados coletados em campo para modelagem tridimensional da área do divisor de águas dos arroios Chuí e Pastoreio. Em ambiente de SIG (Sistemas de Informações Geográficas) foram realizadas interpolações de cotas altimétricas dos pontos coletados em campo utilizando-se os métodos da krigagem e TIN (triangulated irregular network). Através da análise dos modelos tridimensionais gerados, foi identificado o ponto divisor de águas dos arroios, sendo determinante para a posterior delimitação da microbacia do arroio Chuí. A partir da identificação do divisor de águas e conhecimento da nascente do arroio Chuí, foi possível a definição do limite superior da microbacia, e assim caracterizar com maior precisão suas formas e dimensões. Com o uso dos dados do SRTM corrigidos, para a região sul do estado, foram geradas curvas de nível com precisão de 5m, interpolando suas cotas mais elevadas com a ferramenta Watershed (ArcGIS 10®) e definindo-se a área da microbacia do arroio Chuí com 58.796,72ha. Tais métodos de trabalho mostraram-se eficazes na caracterização morfométrica da área de estudo e proporcionaram subsídios ao mais preciso dimensionamento da microbacia do arroio Chuí, acarretando no melhor manejo dos recursos naturais dispostos.
The knowledge of the structures, features and forms a drainage basin is part of the recognition of his evolution and dynamics. Addressing the geomorphological and dynamic evaluation, we highlight all physical environmental factors inherent to the formation of structures and features. This paper has the main objective to propose a morphometric characterization of the Arroio Chuí basin from the identification of the watershed adjacent to Arroio Pastoreio, the southern state of Rio Grande do Sul. Identifying the source of the Arroyo Chuy, was preliminarily performed by analysis on satellite image Landsat 5 sensor TM of 2009 associated with the digital elevation model (SRTM and later identified by survey in field. In the field, topographic survey was conducted in the watershed region in order to better characterize the soft morphological variations of the area. In the laboratory, were processed and refined data collected in the field for three-dimensional modeling of the watershed of the Arroio Chui and Arroio Pastoreio. In the GIS (Geographic Information Systems) interpolations of elevations points collected in the field using the methods of kriging and TIN (triangulated irregular network) were performed. Through the analysis of three-dimensional models generated, the dividing point of the rivers of waters, being decisive for the further delineation of the Arroio Chuí basin was identified. From the identification of the watershed and the source of knowledge Arroyo Chuy, we define the upper limit of the basin, and so more accurately characterize their shapes and dimensions. With using a digital elevation model SRTM adjusted of the southern state, level curves were generated with an accuracy of 5m, interpolating their highest values with the Watershed tool (ArcGIS®10) and defining the area of the Arroio Chuí basin to 58796.72ha. Such working methods were effective in morphometric characterization of the area and provided subsidies to more accurate sizing of the Arroyo Chuy basin, resulting in better management of natural resources arranged.

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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Este trabalho propôs uma pesquisa interdisciplinar entre a Geologia e a Arqueologia, buscando compreender, a partir de uma perspectiva geoarqueológica, a relação entre a evolução da Planície Costeira do Rio Grande do Sul (PCRS) e a ocupação humana pretérita na área. Nossa área de estudo foi o Litoral Norte do estado, nos limites do município de Arroio do Sal, onde utilizamos o Radar de Penetração de Solo (GPR) para adquirir perfis onde foi possível identificar feições pretéritas que indicaram configurações da planície favoráveis à ocupação humana na região. A partir dos dados coletados na PCRS foi realizada uma interpretação do possível cenário no qual antigos grupos humanos viveram, mostrando a presença de antigas lagoas e lagunas hoje colmatadas. A mesma ferramenta geofísica foi utilizada em aquisições no sambaqui Marambaia I (RS-LN-312). Com as informações obtidas, criamos um mapa indicativo de locais propensos à presença de materiais arqueológicos, esperando diminuir assim erros e custos em futuras escavações e manter a integridade do sítio.
This work is an interdisciplinary research between Geology and Archeology. It aims to understand from a geoarchaelogycal perspective the relationship between the evolution of the northern portion of the coastal plain of the Rio Grande do Sul State (PCRS) and the preterit human occupation in the area. Our study area is located within the limits of the Arroio do Sal municipality. Ground Penetrating Radar (GPR) devices were used to acquire profiles in which were identified past coastal plain features favorable to human occupation of the region. From the data collected an interpretation of the possible scenario in which ancient human groups lived was elaborated, including the presence of currently filled back barrier lakes and lagoons. The same geophysical tool was used for subsurface acquisition in the shell mound named Marambaia I (RS-LN-312). The results have allowed the elaboration of a map of places prone to the presence of archaeological materials, hence hoping to reduce errors and costs in future excavation and therefore to preserve as much as possible the site integrity.

L'Algérie connut sous la colonisation française la constitution d'une armature urbaine nouvelle via la création des "centres européens de peuplement". Notre travail de recherche vise le dégagement du processus général et des procédures relatifs aux projets de création, soit affiliés à des programmes planifiés, ou simples échos d'une logique ponctuelle dictée par opportunités et faits accomplis. Il s'impose avant cela, de relever dans leur contexte historique et géographique, les différentes structures politiques, institutionnelles, administratives et techniques alors impliquées. Il apparaîtra derrière l'œuvre homogène visible de l'armature urbaine formée, une suite de tentatives intimement liées aux contextes dans lesquels elles s'inscrivent, loin du phénomène monolithique et linéaire. La Kabylie du Djurdjura, terrain accidenté, densément peuplé et contraire aux besoins extensifs de la colonisation, aura concentré et amplifié l'action fragmentaire de l'occupation territoriale entre 1857, date tardive de conquête, et l'année 1899 qui clos le peuplement dans la région. Elle constituera pour nous un prétexte pour reconstituer en temps réel, le processus, les procédures et mettre en scène acteurs et projets
Algeria knew under the French colonization the constitution of a new urban reinforcement via the creation of "centre européens de peuplement" (European centres of settlement) this research study aims at the release of the general process and of procedures related to the projects of the creation of these centres, knowing these projects were affiliated to precise programs (systems) or following a specific logic guided by opportunities and facts. It is then essential to raise in their historical and geographic context the multiple political, institutional, administrative and technical structures involved in the colonization projects. It appears that behind an homogenous work representing the urban reinforcement, a territorial action far from the monolithic and linear phenomenon for a succession of attempts intimately related to the context in which it fit. The Kabylia of Djurdjura a rocky mountain ground, densely populated and opposed to the extensive needs of colonization has concentrated and amplified the fragmentary action of a territorial colonization between 1857 (late date of conquest) and 1899 (the official date closing the settlement in the region) will constitute for us an excuse to reconstitute in real time the process, the procedures, the actors and their projects

A área de estudo do presente trabalho é parte integrante da barreira holocênica do estado do Rio Grande do Sul. Apresenta seus limites entre o balneário de Itapeva (município de Torres) ao norte e, ao sul, o balneário de Dunas Altas (município de Palmares do Sul). Este trabalho teve por objetivo obter novas informações referentes às variações sazonais (inverno e verão) morfológicas e sedimentológicas (granulometria e morfoscopia) do sistema praia-duna frontal no Litoral Norte do Rio Grande do Sul, Brasil. Para isso, foram coletadas e analisadas por difração a lazer (granulometria) 26 amostras de sedimentos das dunas frontais (face marinha) e 26 da praia (nos limites instantâneos da zona de espraiamento), bem como as suas características morfológicas através de medição, observação e descrição em campo. Os resultados obtidos demostraram nítida relação sedimentológica entre a praia e a duna frontal quando observados na mesma estação. No ambiente praial, os sedimentos foram caracterizados como areia fina com tendência granocrescente para o norte, bem selecionados, aproximadamente simétricos e mesocúrticos no verão, com tendência a leptocúrticos no inverno. Nas dunas frontais os sedimentos foram classificados como areia fina, com tendência granocrescente para o norte no inverno e um sutil decréscimo no verão, bem selecionados a muito bem selecionados e aproximadamente simétricos, mesocúrticos com tendência leptocúrticos nas duas estações. No inverno, a praia apresentou areias com maior valor de diâmetro médio em relação ao verão, da mesma forma que as a dunas frontais. Quanto à morfoscopia (verão/inverno), os grãos foram classificados como angulosos com média esfericidade. Com relação à análise das variáveis morfológicas, a largura da praia e a pista de vento não apresentaram relação com a altura das dunas frontais. As mesmas tendem a um decréscimo de sul para norte. As maiores alturas de dunas foram encontradas ao sul, onde há maior velocidade dos ventos e em função da orientação da linha de costa que determina uma incidência com maior valor angular do vento dominante proveniente de nordeste.
The study area of this work corresponds to the beach-foredune system of the Holocene barrier of the Rio Grande do Sul state. It presents its boundaries between Itapeva (Torres municipality) to the north and Dunas Altas (Palmares do Sul municipality) to the south. The objective of this work was to obtain new information regarding seasonal (winter and summer) morphological and sedimentological variations (granulometry and morphoscopy) of the beach-foredune system in the northern coast of Rio Grande do Sul, Brazil. For this, 26 samples of sediments of the foredunes (marine face) and 26 of the beach (at the instantaneous limits of the swash zone) were collected and analyzed by laser diffraction (granulometry), as well as their morphological characteristics through the measurement, observation and field description. The results obtained showed a clear sedimentological relationship between the beach and the foredune when considered the same season. At the beach the sediments were characterized as fine sand with a tendency to a northward increase on grain size. These sands are well selected, approximately symmetrical and mesocurtic in the summer, with tendency to leptocurtic in the winter. In the foredunes the sediments were classified as fine sand, with a tendency to a northward increase on grain size in the winter, and a subtle decrease in the summer. These sands are well selected to very well selected and approximately symmetrical, mesocurtic with a leptocurtic tendency in the two seasons. In winter the beach and the foredune presented sands with a higher value of average diameter in relation to the summer. In regard of morphoscopy (summer/winter), the grains were classified as angular with moderate sphericity. Regarding the analysis of the morphological variables, the width of the beach and the wind fetch were not related to the height of the foredunes. They tend to decrease from south to north. The highest heights of dunes were found to the south, where there is higher wind velocity, due to the orientation of the coastline that determines a higher angular value of incidence of the dominant wind coming from the northeast.

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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
CNPQ – Conselho Nacional de Desenvolvimento Científico e Tecnológico
A região costeira do Estado do Rio Grande do Sul é constituída por uma extensa faixa de terras baixas e arenosas dominadas pela ação de ondas, deriva litorânea e demais correntes induzidas por ondas, além da forte ação do vento. O presente estudo teve por objetivo relacionar e detalhar a dinâmica de formação de um antigo ambiente praial localizado em áreas de duas jazidas de areia no município de Osório (RS). A região está inserida na parte norte da Planície Costeira do Rio Grande do Sul, no Sistema Barreira III, de idade pleistocênica (120 a 125 ka). Este sistema contém depósitos de foreshore e shoreface recobertos por sedimentos eólicos. Na região, há um registro significativo de estruturas sedimentares biogênicas marinhas e não marinhas que permitiram demarcar com clareza os depósitos praiais. Além da análise de fácies e processos sedimentares, os dados de paleocorrentes permitiram inferir a paleolinha de praia da Barreira III na região de Osório (RS), traçando um comparativo com o atual regime de ondas, correntes e ventos que atuam na região litorânea do Estado do Rio Grande do Sul.
The coastal region of Rio Grande do Sul consists of a long track of low and sandy dominated by the action of waves, littoral drift and other currents induced by waves as well as the wind strong action. The present study had the objective of relating and specifying the formation dynamics of an ancient beach environment located in the area of two sand mines in the two of Osório, in Rio Grande do Sul. The region is inside the north part of the Coastal Plain of Rio Grande do Sul (Planície Costeira do RS), in Barrier System III, of pleistocenic age (120 to 125 ky). This system contains foreshore and shoreface deposits covered by eolian sediments. In the region, there is a significant register of marine and non-marine biogenic sedimentar strutures that allowed to mark clearly the marine deposits. Besides the analysis of facies and sedimentary processes, paleocurrent data allow infer the beach paleoline of Barrier III in the region of Osório (RS), making a comparison with the present regime of waves, currents and winds that act in the coastal region of Rio Grande do Sul.

A conectividade é um fator chave na manutenção de metacomunidades. A conectividade hidrológica vem sendo estudada ao longo dos anos, porém poucos trabalhos de fato discriminam, apropriadamente, os conceitos de conectividade estrutural e funcional. O sistema Tramandaí possui formação geológica recente, situa-se na região do litoral norte do estado do Rio Grande do Sul e possui 41 lagoas conectadas por canais que foram categorizados previamente através de valores de atrito baseados no custo de dispersão dos peixes. Porém, essas conexões não foram exploradas empiricamente, com isso nosso objetivo é investigar a composição de peixes e a influência da configuração do hábitat na estruturação e dinâmica desta ictiofauna interlagunar. Foram amostrados 56 sítios ao longo de 23 conexões entre as estações quente e fria, onde foram coletados peixes com rede de arrasto e puçá e foram realizados levantamentos da estrutura de hábitat local. As análises mostraram alta correlação entre as espécies das lagoas e das conexões, indicando um efeito de massa no sistema. O tamanho das espécies foi em média pequeno, fortalecendo a ideia de que as margens de ambientes aquáticos servem de berçário e proteção contra a predação. A categorização baseada em valores de atrito prediz uma diferenciação em termos de hábitat e composição de espécies nas conexões. Além disso, foi detectada influência de fatores ambientais como temperatura, fluxo de água e transparência sobre a riqueza – sendo que a temperatura apresentou relação direta e fluxo de água e transparência relação inversa. A temperatura, galhos e troncos, largura, fluxo de água, oxigênio dissolvido e salinidade influenciaram a composição de espécies principalmente no verão. No inverno foi detectada pouca influência do hábitat sobre a composição. Estes resultados indicam que a configuração do hábitat nas conexões é importante para determinar apropriadamente a conectividade interlagunar do sistema, principalmente em períodos de grande ocupação destes ambientes. O gradiente ambiental (espacial e temporal) nas conexões, e a influência do hábitat na composição de espécies, mostram que além do modelo de efeito de massa, a seleção de espécies pelas condições de hábitat é atuante nessa metacomunidade.
The connectivity is a key factor on structuring metacommunities. The hydrological connectivity has been studied along the years, but only a few works indeed properly distinct the concepts of structural and functional connectivity. The Tramandaí system is a geological early formation located in the north coast of the Rio Grande do Sul state in Southern Brazil and has 41 costal lagoons connected by channels. These connections were categorized by friction values based on costs of dispersion for fishes. But, those connections were never explored empirically, and our goal is to investigate the fish composition and the influence of habitat configuration on the fish fauna dynamics and structure along the connections to access the more realistic functional connectivity. 56 sites in 23 connections were sampled in both warm and cold seasons, the fishes were collected by seine and dip net and also habitat surveys were conducted. The data analysis showed high correlation between the lagoons and the connections species, suggesting a mass effect in the system. The species body size were average small, empowering the idea that shore habitats works as nursery areas and for predator avoidance. The connection’s categories based on friction values indeed predict habitats and composition distinctiveness. Environmental features were detected as influent over richness, like the temperature with a direct relation and water flow and transparency in an inverse relation. The temperature, branches and trunks, width, water flow, dissolved oxygen and salinity influenced the species composition along the year and in the summer. In the winter a short influence of the habitat configuration over composition were detected. This results indicate that the habitat configuration in the connections is important to determinate properly the functional connectivity, mainly in high occupation periods in this environments, like in the summer. The environmental gradient (both temporal and spatial) in the connections, and the habitat influence over the species composition, show that not only the mass effect, but also the species sorting acts in this metacommunity.

O Sistema Laguna-Barreira III é o sistema deposicional pleistocênico mais preservado do sul da Planície Costeira do Rio Grande do Sul. A origem dessa unidade está correlacionada ao alto nível do mar do último estágio interglacial, mas até agora pouco se conhece sobre sua evolução e estratigrafia devido à escassez de afloramentos. Uma assembleia de fósseis constituída por milhares de bivalves e gastrópodes foi recuperada de perfurações e sondagens SPT (Standard Penetration Test), em profundidades de até 17 metros, realizadas sobre essa unidade. A caracterização desses fósseis e a análise dos sedimentos e dos dados dos SPTs permitiu identificar depósitos de retrobarreira representando uma sequência retrogradacional caracterizada por fácies de fundo e margem lagunar sobrepostas por fácies eólicas arenosas, recobertas por depósitos de loess. A assembleia de fósseis, encontrada em depósitos de fundo e margem lagunar, é dominada por moluscos bivalves e gastrópodes, em sua maioria característicos de ambiente marinho franco raso (≤ 30 metros), mas também inclui alguns bivalves típicos de ambiente lagunar, como Erodona mactroides e Anomalocardia brasiliana A presença de espécies que não vivem atualmente nessa região sugere a influência de águas costeiras mais quentes durante o último estágio interglacial. O bom estado de preservação da maior parte da assembleia de moluscos, sem sinais de abrasão, bioerosão ou incrustação, indica curto tempo de residência na interface sedimento-água após a morte, seguido por rápido soterramento abaixo da Zona Tafonomicamente Ativa (TAZ). A presença de espécies marinhas juntamente com espécies de ambientes mixohalinos de baixa energia indica o transporte de sedimentos e fauna marinhos para a retrobarreira, o que teria ocorrido durante a fase transgressiva da evolução do Sistema III. Esse processo poderia estar relacionado ao aumento de tempestades durante o último interglacial, promovendo o transporte de grandes quantidades de sedimentos e conchas da face praial para a retrobarreira através de sobrelavagem da barreira (overwash) e abertura de inlets efêmeros.
The Barrier-Lagoon System III is the most preserved Pleistocene depositional system in the southern Coastal Plain of Rio Grande do Sul. The origin of this unit is correlated to the sea-level highstand of the last interglacial stage, but so far very little is known about the evolution and stratigraphy of this unit due to the scarcity of outcrops. A fossil assemblage consisting of thousands of bivalve and gastropod shells were recovered from drilling holes and SPT (Standard Penetration Test) surveys performed at depths up to 17 meters on that unit. The characterization of these fossils in addition to the analysis of the sediments and SPT data allowed to identify backbarrier deposits representing a retrogradational sequence characterized by lagoon bottom and margin facies superposed by sandy aeolian facies, covered by loess deposits. The fossil assemblage found in the lagoon bottom and margin deposits is dominated by bivalve and gastropod molluscs, mostly characteristic of open marine, shallow (≤ 30 meters) environment, but including some Erodona mactroides and Anomalocardia brasiliana, bivalves typical of lagoon environments The presence of species that do not currently live in the region suggests the influence of warmer coastal waters during the last interglacial stage. The good state of preservation of a large part of the molluscan assemblage, with no signs of abrasion, bioerosion or incrustation, indicates short residence time at the sediment-water interface after death, followed by rapid burial below the Taphonomically Active Zone (TAZ). The presence of marine species together with species from low energy mixohaline environments indicates the transport of sediments and marine fauna to the backbarrier, which would have occurred during the transgressive phase of the System III evolution. This process could have been related to increased storminess during the last interglacial, which promoted the transportation of large amounts of sediments and shells from the shoreface to the backbarrier through overwash and opening of ephemeral inlet channels.

Diatomáceas do Quaternário são indicadoras úteis de alterações de habitats locais desde ambientes terrestres até ambientes marinhos profundos, produzindo conhecimento a respeito de alterações do nível da coluna d'água em lagos, mudanças do nível relativo do mar e química da água. Embora extensamente utilizadas por pesquisadores europeus e norte americanos, no Brasil, o potencial paleontológico das diatomáceas ainda é pouco explorado, haja vista o reduzido número de trabalhos publicados em que a análise deste grupo constituiu objetivo central. Para o caso da Planície Costeira do Rio Grande do Sul, o papel suplementar das diatomáceas nos estudos paleoecológicos efetivados torna-se manifesto em função do inexpressivo número de espécies citadas. Além disso, no que tange ao processamento dos dados nestes estudos, a definição de intervalos fundamentou-se em critérios subjetivos dos pesquisadores já que, exceção à parte, não são mencionados procedimentos estatísticos de exame dos resultados quantitativos. Neste contexto, executou-se pesquisa visando reconstituir os sucessivos paleoambientes do sistema lacustre Pinguela-Palmital-Malvas na porção emersa norte da Bacia de Pelotas, durante o Holoceno a partir de 89 amostras do testemunho de sondagem PM-RS-D01 com 4,87 m de profundidade total, utilizando diatomáceas como descritores. Uma maior objetividade dentro deste enfoque foi obtida pela definição de espécies indicadoras de conjuntos de unidades amostrais oriundos de níveis de particionamentos significativos em análises de agrupamento, prática importada do estudo da ecologia de espécies atuais. Desta forma, um pequeno número de espécies representativas para determinado intervalo estratigráfico atuaram como descritoras, a partir das quais inferências paleoambientais puderam ser desenvolvidas. O poço revelou as assembléias de diatomáceas fósseis mais diversificadas para estudos até então conduzidos na Planície Costeira Norte do Rio Grande do Sul. Estas refletiram essencialmente oscilações de habitats decorrentes de atores climáticos e eustáticos que marcaram de maneira evidente duas fases distintas da história evolutiva recente do Sistema Pinguela-Palmital-Malvas. Inicialmente, no período compreendido entre 4.600 +/-70 anos AP e 3.950 +/- 70 anos AP, ocorre alternância entre estratos compostos pela preponderância de tafocenoses mixohalinas e intervalos caracterizados pela supremacia de espécies dulciaqüícolas em um contexto transgressivo. Ali, os registros determinados por Actinocyclus normanii, Cyclotella striata e Diploneis smithii refletem períodos de clima mais seco, quando o volume de água doce drenado para a bacia era menor e a evaporação mais intensa. De forma inversa, Aulacoseira cf. agassizii determinou o esclarecimento de etapas de incremento do afluxo lótico por variação positiva do regime pluviométrico intensificado em decorrência do estabelecimento de condições provavelmente relacionados à vigência do fenômeno El niño. Após 3.950 +/- 70 anos AP, alterações sedimentológicas e bióticas significativas como o estabelecimento de fácies com predomínio de areias e a maior diversidade e abundância de vestígios de espécies perifíticas, caracterizam o início do processo de regressão correlacionável com o registro de diversos pesquisadores do Holoceno da Planície Costeira gaúcha. No entanto, a análise diatomológica revelou heterogeneidade ambiental inédita para o trecho, comprovando a existência de um processo constituído por, pelo menos, cinco rompimentos da tendência predominantemente regressiva bem como de momentos de russurgência de período climático úmido e seco. A manutenção da coerência das interpretações paleoambientais obtidas, quando confrontadas a estudos pregressos, e a detecção de processos originais para a região, assinalam a eficiência dos procedimentos estatísticos empregados baseados no estabelecimento de agrupamentos significativos e destaque à espécies reguladoras destes particionamentos.
Quaternary diatoms are useful indicatives of alterations occurred in local habitats, since terrestrial as well as deep marine environments, producing knowledge concerning alterations of the water column level in lakes, changes in sea level and the chemistry of the water. Although extensively utilized by European and North American researchers, the paleontologic potential of diatoms is still little explored in Brazil, taking into account the small number of papers published on the subject. In the case of the Coastal Plains of Rio Grande do Sul, the supplementary role of diatoms in paleoecological studies is expressed through the inexpressive number of species mentioned in paleolimnological publications. Furthermore, as far as data processing is concerned, the definition zones in these studies was based on subjective criteria once statistical procedures of quantitative results were not mentioned. In this context, a research was conducted aiming to reconstitute paleoenvironments of the lacustrine Pinguela-Palmital-Malvas System, on the emerged portion north of Pelotas Basin during the Holocene. This study is based on 89 subsurface samples from the PM-RSDO1 core (4,87 m of total depth), using diatoms- as descriptors. Thus, a better objectivity was obtained by defining the species indicative of sets of sampling units originated from levels of significant partitioning in grouping analyses, a practice imported from the study of actual ecology. This way, a small number of representative species of a certain stratigraphic interval acted as descriptors, from which paleonenvironmental inferences were drawn. The core revealed the most diversified assemblages of fossil diatoms for studies conducted on the Coastal Plains North of Rio Grande do Sul. Essentially, they reflected oscillations of habitats resulting from climatic and eustatic actors that clearly set two distinct phases of recent evolutionary history of the Pinguela-Palmital-Malvas System. Initially, between 4.600 +/- 70 years BP and 3.950 +/- years BP, an alternation occurred between strata constituted predominantly by mixohaline taphocenoses and intervals characterized by supremacy of freshwater species in a transgressive context. There, records of Actinocyclus normanii, Cyclotella striata and Diploneis smithili reflect periods of a drier climate as the volume of fresh water drained into the basin was smaller and evaporation was more intense. On the contrary, Aulacoseira cf. agassizii determined the clarification on stages of increment of the lotic influx through positive variation of intensive pluviometric regime due to conditions probably related to El niño phenomenon. After 3.950 +/- 70 years AP, significant sedimentological and biotic alterations, like the establishment of facies with sandy and greater diversity and abundance of signs of periphytic species characterize the beginning of the regression process likely to be correlated with the record of several researchers of the Holocene of these Coastal Plains. However, the diatomalogic analysis revealed an environmental heterogeneity unusual for that stretch, proving the existence of a process constituted of at least five ruptures on a predominantly regressive tendency, as well as moments of resurgence of a humid and dry climatic period. The maintenance of these coherent paleoenvironmental interpretations, compared with previous studies, and the discovery of original processes for the region show the efficiency of the statistical procedures here used, based on the establishment of significant groupings and the prominence of regulating species from this partitioning.

L’objectif de cette recherche est de comprendre comment des facteurs d’ordre social et environnemental ont influencé, en Amazonie brésilienne, le peuplement, l’appropriation et l’usage conjugué des ressouces naturelles, dans une région de transition entre des écosystèmes de plaines d’inondation et de terre ferme. L’approche adoptée est historique et ethnographique, afin d’examiner comment les relations de pouvoir et les pratiques sociales sont articulées au régime hydraulique de crues et d’étiages. Le lieu de l’étude est la région du Lago Grande do Curuai, dans la commune de Santarém (État du Pará), au croisement des communes d’Óbidos et Juruti. Je me suis interrogé sur de possibles continuités et ruptures entre les relations de pouvoir actuelles et celles de l’époque coloniale – relations qui influencent la circulation des hommes entre ces deux écosystèmes. Je conclue que les plaines d’inondation (várzeas) sont, aujourd’hui encore, contrôlées par des segments sociaux issus de l’élite locale, formés de propriétaires terriens et d’éleveurs de bovins. Ceux-ci ont construit leur pouvoir pendant la colonie portugaise et ont graditativement impulsé un mouvement vers des terres situées de plus en plus loin dans la terre ferme, avançant sur la forêt. Depuis 1950, l’élevage est la principale activité économique à l’origine de cette expansion, au moyen des pratiques liées à la transhumance du bétail. Parmi les facteurs qui induisent la circulation saisonnière entre la várzea et la terre ferme, la transhumance a reçu une attention particulière dans ce travail. Initialement réservée aux grands fazendeiros, cette pratique s’est popularisée dès les années 1970 parmi les différents profiles d’éleveurs, avec une intensification dans les années 1990. L’élevage repose sur trois pratiques locales qui favorisent la transumance : les « sociétés », les « permissions » et les locations de terrain (arrendamentos). Leur analyse conjointe m’a permis de montrer que les « sociétés » entre grands et petits éleveurs sont à l’origine de l’expansion de l’élevage. Cette activité va bien au-delà d’un « livret d’épargne » ; elle confère du prestige et une opportunité d’accéder régulièrement aux plaines d’inondation. Lors de la création, en 2005, d’un projet d’établissement agro-extractiviste – le PAE Lago Grande – afin de régulariser l’occupation foncière des populations régionales, seuls les terrains de terre ferme ont été intégrés dans la nouvelle unité territoriale. Ceux de várzea en ont été exclus. Les données disponibles permettent de montrer qu’au fond, la structure foncière n’a pas été modifiée. Dès lors, les relations de pouvoir historiquement inscrites dans ce paysage restent relativement inchangées. Enfin, la circulation des populations régionales entre ces deux écosystèmes ainsi que les pratiques de transhumance n’ont pas été prises en compte lors de la mise en œuvre des politiques de gestion territoriale en Amazonie
The aim of this study is to understand the role of the social and environmental order influenced the peopling, land appropriation and the seasonal use of natural resources between floodplains (várzea) and firm land (terra firme) ecosystems in the Brazilian Amazon. I follow an historical and ethnographical approach to examine how social practices and the local power relations influenced the interrelated dynamic between social life and water movements (floods and droughts). The study area is Lago Grande, located in the city of Santarem, Pará State bordering the towns of Óbidos and Juruti. The main question is to investigate if power relations among social groups established and inherited during the colonial living in Lago Grande region are still operating in current times, and how this situation affects the control of transhumance between várzea and terra firme ecosystems. I conclude that the Amazon floodplains are still controlled by local elites, represented by land and livestock owners. The local elite established their socio-political power during colonial times, dominating an increasing process of entering from várzea to terra firme areas (i.e. deforestation). Since 1950, the main economical activity responsible for the expansion of land use from várzea to terra firme was cattle raising through transhumance between both ecosystems. Transumance has received a specific attention in this study, for it is among the main factors encouraging the circulation of local population between várzea and terra firme environments. From 1970’s, large farmers started the transhumance which was later followed by smaller farmers, and intensified through the 1990’s. Cattle ranching builds on three local practices which promote transhumance: “societies”, “permissions” and land rentals (arrendamentos). A joint analysis allowed me to demonstrate that “societies” between large and small farmers sustain the cattle ranching growth. This activity is lucrative and bestows prestige and opportunities to access the floodplains more regularly. In 2005, an Agro-extractivist Settlement was created (PAE Lago Grande) to favor land distribution and better economical opportunities among local populations. Though, the territorial unit included terra firme but not the areas of the várzea ecosystem, vital for the local economy part of the year. Additionally, the PAE also did not alter the land tenure, keeping the same historically constructed power structures it aimed to deconstruct
O objetivo geral desta pesquisa foi compreender como fatores de ordem social e ambientalinfluenciaram o povoamento, a apropriação e o uso conjugado dos recursos naturais em umaregião de transição entre os ecossistemas de várzea e de terra firme na Amazônia brasileira.Adotei uma abordagem histórica e etnográfica para examinar como relações de poder e práticassociais mediaram a articulação da vida social ao regime de cheias e vazantes. A área eleita paraa realização da pesquisa foi a região do Lago Grande, localizada no município de Santarém-PA, na confluência com os municípios de Óbidos e Juruti. Questionei se seria possível, naatualidade, enxergar nas relações entre os segmentos sociais que coabitam a região do LagoGrande continuidades e rupturas com as relações de poder herdadas do período colonial e comotais relações poderiam estar intervindo na circulação humana entre os dois ecossistemas.Conclui-se que as várzeas ainda são controladas por segmentos das elites locais, formadas porproprietários de terras e gado. Estes fundaram seu poder no período colonial e lentamentecomandaram o processo de ampliação dos sistemas de uso da terra para os interiores da terrafirme. Desde 1950, a principal atividade econômica a impulsionar esta expansão tem sido apecuária, por meio da prática da transumância. Entre os diversos fatores que sustentam acirculação sazonal entre a várzea e a terra firme pela população local, a transumância recebeuatenção especial da pesquisa. Iniciada pelos grandes fazendeiros, a transumância se popularizouentre os diversos perfis de criadores a partir das décadas de 1970 e foi intensificada na décadade 1990. Três instituições comandam a atividade pecuária e logo sustentam a transumância: as“sociedades”, as permissões e os arrendamentos. Analisados em conjunto estes institutospermitiram que a pesquisa chegasse à conclusão de que as “sociedades” entre grandes epequenos criadores sustentam o crescimento da pecuária, atividade que muito mais do que umasimples poupança é sinônimo de prestígio e oportunidade de acesso regular a várzea. A criaçãode um projeto de assentamento agroextrativista em 2005, o PAE Lago Grande, anexou apenasa faixa de terra firme da região do Lago Grande, deixando as várzeas de fora. O PAE não anexouas várzeas e não alterou a estrutura fundiária em terra firme. Desta forma, pouco alterou asrelações de poder historicamente construídas. Por fim, considera-se que a circulação realizadaentre as populações regionais entre os dois ecossistemas, de maneira geral, e a transumância,em particular, não vem sendo levada em consideração nas políticas de ordenamento territorialna Amazônia

With more than ¾ of the forest surface of Cameroon allocated to logging, the survival of many rainforest species will depend on the way in which timber production forests will be managed in this country for the next decades. Management decisions to be applied should be directed systematically towards a minimization of the negative impacts on the ecosystem as a whole, including on the animal populations living in these forests. This requires a detailed understanding of the response of wildlife to selective logging as it is currently practised in Central Africa.

This thesis reports results of a longitudinal monitoring of abundances of nine mammal species in a forest concession over a four years period. From 2003 to 2006, four wildlife censuses have been conducted in the active core of FMU 10.030 allocated to the logging company PALLISCO. Our study area covers 176 sq-km and include several logging compartments and unlogged areas.

The diversity of specific responses to the introduction of human activities into the habitat is at the scale of the biological diversity of the habitat itself. A particular attention was paid to two emblematic species of the Cameroonian forests, western lowland gorillas G.g. gorilla and the common chimpanzees Pan troglodytes. During this work, we studied 1) how logging at industrial scale affects the spatial distribution of nine mammal species, including great apes, in timber production forests of South-eastern Cameroon, and 2) the nature of pressures exerted on animal populations within an active forest concession (anthropic, ecological, ethologic, etc).

Our first results indicate that the extraction of valuable timber species generates a spatial reorganization of gorillas and chimpanzees, inducing local modifications of population densities. This spatial reorganization seems to be mainly due to human activities per se rather than to modifications of the habitat structure or changes in the availability of fruits for these species. Compared with other mammals, great apes are at the two extreme opposites of a gradient of sensitivity to the habitat disturbances created by logging. Gorillas, as well as other "generalist" species like duikers, seem to thrive in logged forests, probably attracted in these areas by the secondarisation of the vegetation. Their densities decrease temporarily in logging compartments during logging operations but these species recover quickly, suggesting a repulsive effect of the human presence in the forest rather than a major alteration of the habitat quality for them. Rather "specialist" species seem to react by increasing the size of their foraging area. These are the sitatungas Tragelpahus spekei and bushpigs Potamochoerus porcus, two typical species of swamp forest with Raffia spp. and semi-inundated forests. These particular biotopes in the heart of the production forests seem to be playing the role of refuge zone for these species. Finally, two species were identified as being explicitly vulnerable to logging activities: the chimpanzees and forest elephants Loxodonta africana cyclotis. Their abundances did not recover to original values during the period of study indicating that they still undergo some kind of ecological and/or anthropic pressures after the end of logging operations that is strongly adverse to them.

In order to contrast the ecological and/or anthropic factors ruling gorillas' and chimpanzees' spatial distribution in the habitat, we have used a spatial modelling technique called “Ecological Niche Factor Analysis - ENFA". ENFA-generated models for these two species mainly retained anthropic variables to explain great apes local repartition in the study area. For gorillas, it was mainly explained by the local pattern of logging compartments and the time that passed since the end of logging operations. Globally, this species avoids the areas of forests showing a high rate of human frequentation and is attracted to old logged areas. As for the chimpanzees, their spatial distribution is influenced mainly by the presence of roads which are largely avoided. The periphery of logged compartment seems to be a zone of convergence for chimpanzee communities that have probably been driven out from logging compartments during operations, but these movements of populations would be limited to short distances. The vulnerability of the chimpanzees is consequently explained by the absence of demographic mechanisms enabling them to avoid the disturbed zones while reducing the territorial conflicts.

The general trend in great ape abundances in an active logging concession confirms that even closely related species can show divergent capacities of survival when confronted to human disturbances. Our work highlights that chimpanzee communities demonstrate some spatial inertia, contrarily to gorillas which easily manage to avoid human activities. This inertia would be probably at the origin of its sensitivity to current forestry practices. Our results confirm White & Tutin (2001)'s socio-ecological explanation for the vulnerability of chimpanzees to logging in forests of Central Africa. Knowing this, it is imperative to set up concrete conservation actions aiming at maintaining the chimpanzee populations of in Cameroonian timber production forests.

Practically, selective logging would easily be compatible with the preservation of the majority of rainforests mammals if concrete measures aiming at decreasing the negative impacts of logging were effectively applied. As a general rule, the proximity between logged areas and some zones that can serve as refuge seems to be a determining factor of the persistence of rainforests mammals in logged forests. A line of thought would be thus to ensure safe shifts of populations towards these zones in order to guarantee the avoidance of disturbances and, later, the recovery of densities in logged forests. In this sense, our main recommendation consists in promoting a delimitation of logging compartments into narrow strips so as to reduce the distance to be walked by an animal to geographically avoid human disturbances. Additionally, it is necessary to set up well-designed biomonitoring programmes to follow up trends in wildlife abundances and promote a flexible management that can be adapted according to the evidence of detrimental events to wildlife.

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Avec plus de ¾ de la surface forestière du Cameroun allouée à l'exploitation forestière, la survie de nombreuses espèces de mammifères dépendra de la façon dont seront gérés les massifs de forêt de production de ce pays dans les décennies à venir. Les mesures de gestion à appliquer devraient être orientées systématiquement vers une minimisation des impacts négatifs sur l'écosystème dans son ensemble, y compris sur les populations animales résidant dans ces forêts. Ceci nécessite une compréhension détaillée de la réponse de la grande et moyenne faune à l'exploitation forestière sélective telle qu'elle est effectivement pratiquée en Afrique Centrale.

Cette thèse de doctorat rapporte les résultats d'un suivi longitudinal, sur une période de quatre ans, des abondances de neuf espèces de mammifères au sein d'une concession forestière du Sud-est Cameroun. Au total, quatre recensements de la faune ont été réalisés entre 2003 et 2006 dans la partie active de l'UFA 10.030 allouée à la société PALLISCO. La zone étudiée couvre 176 km2 et englobe plusieurs parcelles annuelles d'abattage ainsi que des compartiments non exploités.

La diversité des réponses spécifiques vis-à-vis de l'introduction d'activités humaines dans l'habitat est à l'échelle de la diversité biologique de l'habitat lui-même. Une attention particulière a été portée sur deux espèces emblématiques des forêts camerounaises, les gorilles des plaines occidentales G.g. gorilla et les chimpanzés communs Pan t. troglodytes. Durant ce travail, nous avons étudié 1) comment l'exploitation forestière à l'échelle industrielle affecte la distribution spatiale de neuf espèces de mammifères, dont les grands singes, dans les massifs de forêt de production du Sud-est Cameroun, et 2) de quelle nature sont les pressions exercées sur les populations animales au sein d'une concession forestière active (anthropique, écologique, éthologique, etc.).

Nos premiers résultats indiquent que l'extraction d'essences précieuses dans les forêts camerounaises génère notamment une réorganisation de la distribution spatiale des gorilles et des chimpanzés, induisant des modifications locales de densité de population. Cette réorganisation spatiale semble être due aux activités humaines elles-mêmes plutôt qu'aux modifications de la structure de l'habitat ou à une diminution de la disponibilité de certaines ressources alimentaires importantes pour ces espèces. Comparés à d'autres mammifères, les grands singes se placent aux deux extrêmes d'un gradient de sensibilité aux perturbations de l'habitat causés par l'exploitation forestière. Les gorilles, ainsi que d'autres espèces "généralistes" comme les céphalophes, semblent prospérer dans les forêts exploitées, probablement attirés dans ces zones par la secondarisation de la végétation. Leurs densités diminuent ponctuellement dans les parcelles d'abattage pendant les opérations d'extraction, mais retrouvent très vite leur niveau initial. Ceci suggère un effet répulsif de la présence humaine sur ces espèces plutôt qu'une altération majeure de la qualité de l'habitat pour ces dernières. D'autres espèces plus "spécialistes" semblent réagir en augmentant la taille de leurs aires de fourragement. Il s'agit des sitatungas Tragelpahus spekei et des potamochères Potamochoerus porcus, deux espèces appréciant les biotopes humides (marécages à Raphia spp. des zones de forêt inondées, etc.). Ces biotopes particuliers, non-affectés par l'exploitation forestière, au coeur des forêts de production semblent servir de refuge pour ces espèces. Enfin, deux espèces ont été identifiées comme étant explicitement très vulnérables aux activités d'exploitation: les chimpanzés et les éléphants des forêts Loxodonta africana cyclotis. Leurs abondances n'ont pas recouvré les valeurs originelles durant la période d'étude, indiquant que ces espèces subissent encore des pressions écologiques et/ou anthropiques jusqu'à quatre ans après la fin des activités d'exploitation forestière.

Afin de contraster les facteurs écologiques et/ou anthropiques régissant la distribution spatiale des gorilles et des chimpanzés, nous avons fait usage d'une technique de modélisation spatiale appelée "Ecological Niche Factor Analysis – ENFA". Les modèles ENFA pour ces deux espèces ont principalement retenu les variables anthropiques pour expliquer la distribution spatiale des grands singes dans l'aire d'étude. Il a ainsi été démontré que la répartition des gorilles était en grande partie expliquée par l'agencement local des AACs et le temps qui s'est écoulé depuis la fin des opérations d'extraction dans celles-ci. De manière générale, cette espèce évite les zones présentant un haut taux de fréquentation humaine et préfère les forêts exploitées quelques années auparavant. Quant aux chimpanzés, leur distribution spatiale est principalement expliquée par la présence de routes et pistes forestières qui sont amplement évitées. La périphérie des zones exploitées semble être une zone de convergence pour les chimpanzés qui y seraient vraisemblablement refoulés lors des perturbations, mais ces mouvements seraient limités à de courtes distances. La vulnérabilité des chimpanzés s'expliquerait dès lors par l'absence de mécanismes démographiques leur permettant d'éviter les zones affectées tout en réduisant les conflits territoriaux résultant d'une réorganisation spatiale.

La tendance globale des variations d'abondance des grands singes au sein d'une concession forestière en cours d'exploitation confirme que même des espèces très proches phylogénétiquement peuvent faire preuve de capacités différentes de survie face aux perturbations anthropiques. Il ressort de nos observations que les communautés de chimpanzés font preuve d'une certaine inertie spatiale, contrairement aux gorilles qui parviennent à éviter les activités humaines. Cette inertie serait probablement à l'origine de sa vulnérabilité face aux pratiques forestières actuelles. Nos résultats viennent confirmer l'hypothèse socio-écologique émise par White & Tutin (2001). Face à ce malheureux constat, il est impératif de mettre en place des mesures concrètes de gestion visant à maintenir les populations de chimpanzés dans les forêts de production camerounaises.

Pratiquement, l'exploitation sélective serait compatible avec la conservation de la plupart des mammifères si certaines mesures de gestion visant à diminuer les impacts négatifs étaient rapidement mises en application. La proximité entre les zones exploitées et les zones pouvant servir de refuge semble être un facteur déterminant de la survie de nombreuses espèces de mammifères dans les forêts de production du Cameroun. Une ligne de réflexion serait donc d'assurer les mouvements de populations vers ces zones-refuge sans heurts afin de garantir l'émigration des populations animales en dehors des zones affectées et la recolonisation ultérieure des forêts exploitées. En ce sens, notre principale recommandation consiste à promouvoir un découpage en assiettes de coupe en bandes relativement étroites (<2,5 km) de façon à réduire la distance à parcourir pour éviter géographiquement les perturbations anthropiques. De même, il serait nécessaire de mettre en place des programmes de suivi régulier des abondances faunistiques afin de permettre une gestion adaptative qui s'ajusterait au vu d'événements critiques pour la faune.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished

Pour decouvrir comment se definit le heros tragique dans le western, il nous a semble pertinent de pratiquer une rigoureuse analyse filmique (decoupages "plan par plan", croquis explicatifs) des oeuvres dans lesquelles il s'est le plus illustre. Nous les avons effectivement envisagees comme une mythologie singuliere, ou, sous diverses defroques, apparait notre figure. Loin de toute perspective chronologique, le regroupement des films a donc ete propose par la facon dont s'y presentait l'evolution interne du heros et de sa mission. Qu'y lit-on? en premier lieu (la premiere partie: "l'homme de nulle part", exemple: l'homme des vallees perdues), il s'apparente a un cavalier solitaire aidant une communaute a lutter contre des "mechants" pour creer une societe dont il sera automatiquement rejete, car l'exclusivite de sa fonction lui interdit de se fixer et d'endosser la carapace d'un citoyen. Puis, lorsque les grands espaces se muent en villes (la deuxieme partie: "le retour du banni", exemple: le train sifflera trois fois), il devient un etre soucieux d'une stabilite sociale que viennent lui contester des agresseurs exterieurs, le forcant a constater sa singularite, au moment d'un combat que lui seul peut assumer. C'est tout naturellement qu'il se retrouve ensuite, dans un ouest embourgeoise, vagabond erratique a la recherche d'une action qui ressemble a son identite perdue (la troisieme partie: "l'appel du vide", exemple: la horde sauvage).

Lagoas costeiras são ecossistemas cruciais para conservação da biodiversidade local e global. O sistema do rio Tramandaí (SRT) apresenta uma série de lagoas costeiras rasas conectadas por canais naturais, e uma saída, via estuário de Tramandaí, para o oceano. Esse sistema é dividido em dois subsistemas, ao norte e ao sul do estuário, resultado de padrões hidrodinâmicos e da influência do vento e que definem características ambientais distintas a esses subsistemas. Um gradiente decrescente, de norte a sul, no estado trófico dessas lagoas já foi verificado. No presente estudo é testada hipótese de variabilidade espacial (lagoas e subsistemas) e temporal (estações do ano) na magnitude de variáveis abióticas e de descritores ecológicos das assembleias de peixes (composição, riqueza, diversidade, dominância) do SRT. Também é avaliada a relação entre variáveis abióticas e descritores das assembleias nesses subsistemas. É comparada a seletividade de captura de um amostrador ativo (rede de arrasto de praia) e de um amostrador passivo (redes de emalhe). Amostragens foram conduzidas de novembro de 2008 a abril de 2010 com rede de arrasto de praia e redes de emalhe, na zona litoral das lagoas Itapeva, Quadros e Malvas no subsistema norte, e nas lagoas Fortaleza, Rondinha e Barros no subsistema sul. Entre abril de 2009 e março de 2010, amostras de água foram coletadas e dez variáveis foram mensuradas em laboratório. Análises de ordenação (NMDS) mostraram clara diferença de composição, abundância numérica (CPUEn) e em biomassa (CPUEb) de espécies entre amostradores. A análises de ANOSIM e SIMPER mostraram baixa similaridade desses parâmetros entre amostradores. Houve diferença no tamanho dos peixes coletados com redes de arrasto e emalhe. Turbidez e DBO5 tiveram médias superiores no subsistema norte, enquanto que condutividade, salinidade, dureza, sólidos totais dissolvidos e transparência de Secchi no subsistema sul. Temporalmente foram verificadas diferenças de temperatura, pH, salinidade, turbidez, dureza, sólidos totais dissolvidos, oxigênio dissolvido, sólidos suspensos e profundidade, mas somente os dados de pH, condutividade, turbidez e DBO5 mostraram interação entre os fatores espaço e tempo. As assembleias das margens rasas da zona litoral foram dominadas por dez espécies, resultando em alta similaridade de composição, CPUEn e CPUEb entre os subsistemas. A riqueza de espécies variou espacial e temporalmente. Diversidade e equitabilidade espacialmente, e CPUEn e CPUEb temporalmente. As assembleias das regiões pelágicas da zona litoral foram dominadas por sete espécies, com dominância numérica das espécies L. anus e A. aff. fasciatus no subsistema norte. A NMDS mostrou similaridades maiores de composição, CPUEn e CPUEb entre amostras de um mesmo subsistema, no entanto, a ANOSIM não apresentou resultados significativos para rejeição das hipóteses nulas. CPUE n e b, diversidade e equitabilidade variaram espacialmente, enquanto a riqueza, temporalmente. A análise de correlação canônica (CCA) mostrou que temperatura, DBO5, sólidos suspensos e dureza responderam por 46% da variabilidade dos dados de abundância numérica das espécies. Os resultados sugerem que amostradores ativos e passivos reproduzem diferentes imagens da assembleia por eles amostrada, indicando que o delineamento amostral para estudos com peixes nesses ecossistemas deve contemplar tais diferenças. As diferenças ambientais dos subsistemas refletem em diferenças na qualidade da água e os resultados obtidos confirmam os pressupostos do gradiente trófico. A estrutura das assembleias de peixes foi mais variável em resposta as condições ambientais em escala espacial, enquanto que temporalmente, houve maior coerência na variabilidade dos dados. As relações das espécies com as variáveis ambientais são discutidas com base no comportamento alimentar e/ou reprodutivo das mesmas e na qualidade do habitat. Tais resultados podem ser úteis como subsídio a elaboração de estudos de manejo costeiro do SRT, sobretudo com relação aos recursos pesqueiros, e na proposição de modelos de estrutura das assembleias de peixes de lagoas costeiras subtropicais.
Coastal lakes ecosystems are crucial for conserving biodiversity both locally and globally. The river Tramandaí system (SRT) comprises a series of shallow coastal lagoons, connected by natural channels, and has an output via Tramandaí estuary into the ocean. This system is divided into two subsystems, north and south of the Tramandaí estuary, as result of hydrodynamic patterns, influence of wind and environmental characteristics that define the subsystems. A trophic gradient decreasing from north to south in those lagoons was identified. In this study is tested the hypothesis of spatial (lagoons and subsystems) and temporal (seasons) variabilities in the amplitude of abiotic variables and descriptors of the fish assemblages (species composition, richness, diversity, dominance) in the SRT. It also assessed the relationship between abiotic variables and descriptors of the fish assemblages in these subsystems. Is compared the selectivity of the active fishing (beach seining) and passive (gill netting) fishing. Sampling was conducted from November 2008 to April 2010 with beach seine and gill nets in the littoral zone of lakes Itapeva, Quadros and Malvas in north subsystem, and Fortaleza, Rondinha and Barros lakes, in south subsystem. Between April 2009 and March 2010 water samples were collected and ten variables were measured in the laboratory. Analyses of ordination (NMDS) showed clear differences in composition, numerical abundance (CPUEn) and biomass (CPUEb) of species between samplers. The analysis of similarity (ANOSIM and SIMPER) showed low similarity of these parameters between nets. There was a difference in the size of the fish caught with beach seine and gill nets. Turbidity and BOD5 averages were higher in the northern subsystem, while the conductivity, salinity, hardness, total dissolved solids and Secchi transparency in the south subsystem. Temporally were observed differences in temperature, pH, salinity, turbidity, hardness, total dissolved solids, dissolved oxygen, suspended solids and depth, but only the data for pH, conductivity, turbidity, BOD5 showed interaction between the factors space and time. The assemblages of the shallow margins of the coastal zone were dominated by ten species resulting in high similarity of composition, CPUEn and CPUEb between subsystems. Species richness varied spatially and temporally, while diversity and evenness only spatially and CPUEn and CPUEb only temporally. The assemblages of the pelagic regions of the coastal zone were dominated by seven species with numerical dominance of L. anus and A. aff. fasciatus in north subsystem. The NMDS showed greatest similarity in composition, CPUEn and CPUEb between samples of the same subsystem, the ANOSIM however, showed no significant results for rejection of the null hypothesis. CPUE n and b, diversity and equitability varied between lakes and subsystems, while the richness between seasons. The canonical correlation analysis (CCA) showed that four variables (temperature, BOD, suspended solids and hardness) account for 46% of data variability of species abundance. Samples of the north subsystem were directly influenced by temperature, BOD and suspended solids while the south subsystem by the hardness. The results suggest that active and passive samplers reproduce different images of the assemblage sampled and indicate that the sampling design for studies of these ecosystems should include such differences. The environmental differences in subsystems reflect in water quality differences and the results confirm the assumptions of a trophic gradient decreasing from north to south in the SRT. The structure of the fish assemblages was more variable in response to environmental conditions in spatial scale between subsystems, while there was greater consistency in the temporal variability of the data. The relationships between the species and environmental variables are discussed based on the feeding behavior and / or reproduction of the same and by habitat quality. These results may be useful as an aid to preparing studies of coastal management of SRT, especially with respect to fisheries, and in proposing models of the structure of the fish assemblages of subtropical coastal lagoons.

The Lower Rio Grande Valley (LRGV) of Texas is an ecologically diverse region in the United States and marks the northernmost extension for many tropical species of plants and animals. Since the early 1900s, 95% of the native Tamaulipan brushlands have been cleared due to agricultural practices and urban development. The plain chachalaca (Ortalis vetula) is a medium sized bird endemic to the native brushlands of the LRGV. In 2003, I trapped and radio-tagged 29 birds (16 males, 13 females) to evaluate the effects of fragmentation on the population dynamics (i.e., survival, mortality, and movements) of this brushland species. My study objectives were to estimate (1) seasonal survival of chachalacas by sex, and (2) ranges, core areas, and movements using radio telemetry. Mammalian predation (43%, n = 6) and unknown (43%, n = 6) deaths accounted for the majority of mortality observed. I found no difference (P > 0.05) in estimated 8-month survival (December 2003-July 2004) between males (S = 0.364, SE = 0.132) and females (S = 0.405, SE = 0.153). In comparing seasonal survival for all birds (males and females combined), I observed a difference (P < 0.05) in survival between the nesting (S = 0.414, SE = 0.103) and breeding seasons (S = 0.917, SE = 0.079). Female ranges (x‾ = 117 ha, range = 42–177 ha) and core areas (x‾ = 23 ha, range = 5–46 ha) during the nesting season were larger than male ranges (x‾ = 41 ha, range = 31–46 ha) and core areas (x‾ =10 ha, range = 7–14 ha) during the same period. During the breeding season, female ranges (x‾ = 59 ha, range = 10–188 ha) and core areas (x‾ = 9 ha, range = 2–33 ha) were similar to male ranges (x‾ = 48 ha, range = 4–130 ha) and core areas (x‾ = 9 ha, range = 1–23 ha). Mean distances between seasons were similar for both sexes (females, nesting, x‾ = 486, breeding, x‾ = 345; males, nesting, x‾ = 184, breeding, x‾ = 292), though females distances generally were greater. Dispersal defined as movement off the Santa Ana National Wildlife Refuge was observed for 3 birds. In 2 cases, a radio-tagged female and male were observed crossing the Rio Grande River (approximately 100-m wide) to habitat in Mexico. Study results suggested mammalian predation may limit the growth of chachalaca populations. Though land use changes such as agricultural uses may not directly limit chachalaca populations in providing cover and food, concentration of populations in remnant native brushlands may serve as ecological “sinks” to the species. Greater range and movement data observed in my study may be attributed to suboptimal habitat (i.e., increased fragmentation) for plain chachalacas.

Ecosystem changes from grassland to shrubland in the Rio Grande Plains are thought to have negative effects on the hydrology of the region. The increase in woody plants, known as woody encroachment, may alter the amount of water moving beyond the root zone of plants. Water moving beyond the root zone is referred to as deep drainage, and has potential to become aquifer recharge. A vegetation manipulation project was designed to understand the effects of woody vegetation removal on soil water dynamics in the recharge zone of the Carrizo-Wilcox aquifer of south Texas. The primary objective of the project was to determine the potential to increase groundwater recharge through woody vegetation removal. To understand the effects of vegetation removal on various soil textures we studied changes in soil water, rooting depth, and the role of water redistribution by woody vegetation. Woody vegetation was removed using common methods of cut-stump and roller chop across three soil types. Soil water contents and changes were measured using neutron moisture meter to a depth of 180 cm. Average rooting depth was determined across three soil types. Soil and stem water stable isotopes were used to understand soil water movement. Rooting depth was determined to between 140 and 160 cm for all soil textures. Soil water content and changes were analyzed at three depth increments: 0-60, 60-120 and 120-180 cm. ANOVA analysis showed that there was no treatment response in average soil profile water in the sandy or sandy loam soils. There was a significant decrease in soil profile water for clay loam soil in response to roller chopping. Changes in soil profile water were the greatest in the sandy roller chopped soils. Below 120 cm, three months had significant differences in change in soil water in the sandy roller chop plot. During dry conditions, Honey mesquite shifts water use to deeper in the soil profile. In clay loam soils under dry conditions there is evidence of water being moved up from below 2 m soil depth to drier shallow soils. Roller chopping in sandy soils is the vegetation removal treatment and soil type most likely to result in water moving beyond the root zone. Although treatments had significant effects on soil moisture dynamics that interacted with soil type, we did not find support for deep drainage effects over the Carrizo-Wilcox aquifer from woody vegetation removal.