Previous research in the Ouachita Mountains, Arkansas suggests that, on relatively thin soils overlying bedrock, individual trees locally thicken the regolith by root penetration into bedrock. However, that work was conducted mainly in areas of strongly dipping and contorted rock, where joints and bedding planes susceptible to root penetration are more common and accessible. This project extended this concept to the Cumberland Plateau, Kentucky, with flat, level-bedded sedimentary rocks. Spatial variability of soil thickness was quantified at three nested spatial scales, and statistical relationships with other potential influences of thickness were examined. In addition, soil depth beneath trees was compared to that of non-tree sites by measuring depth to bedrock of stumps and immediately adjacent sites. While soil thickness beneath stumps was greater in the Ouachita Mountains compared to the Kentucky sites, there were no statistically significant differences in the difference between stump and adjacent sites between the two regions. In both regions, however, soils beneath stumps are significantly deeper than adjacent soils. This suggests the local deepening effects of trees occur in flat-bedded as well as steeply dipping lithologies. Regression results at the Cumberland Plateau sites showed no statistically significant relationship between soil depth and geomorphic or stand-level ecological variables, consistent with a major role for individual tree effects. Nested analysis of variance between 10 ha stands, 1.0 ha plots, and 0.1 ha subplots indicates that about 67 percent of total depth variance occurs at, or below, the subplot level of organization. This highly localized variability is consistent with, and most plausibly explained by, individual tree effects. The effects of biomechanical weathering by trees are not limited to areas with strongly dipping and contorted bedrock. Variability of soil depth in the Cumberland Plateau is likely influenced by positive feedbacks from tree root growth, that these interactions occur over multiple generations of growth, and that the effects of trees are the dominant control of local soil thickness. Since lateral lithological variation was minimal, this study also provides evidence that the positive feedback from biomechanical weathering by trees leads to divergent development of soil thickness.

Wave-dominated and mixed tidal and wave energy barrier islands are assumed to have characteristic dune topographies that link to their macroscale form. However, there has been no systematic attempt to describe the linkage between barrier island macroscale form and dune topography. The goal of this thesis was to investigate how dune topographies correspond to a number of barrier island morphologies found along the southeastern U.S. Atlantic coast. Macroscale process-form variables were used to classify 77 islands into seven morphologic clusters. Islands from each cluster were selected and sites characteristic of the range of dune topographies within islands were characterized using three methods: the frequency distribution of elevations, directional spatial autocorrelation of elevation at different distance classes, and FRAGSTATS indices summarizing the patch structure of elevations. Variables derived from each of these methods peaked in their ability to discriminate among barrier island morphologies when the islands were aggregated into three groups. An ordination of those variables revealed a two or three-fold grouping of barrier island dune types that approximated the traditional wave dominated and mixed energy barrier island morphologic classification. These findings suggest that dune topographies converge upon two to three configurations even within the heterogeneity in macroscale island morphology.

Non-point pollution from stormwater runoff is one of the greatest threats to water quality in the United States today, particularly in urban karst settings. In these settings, the use of karst features and injection wells for stormwater management results in virtually untreated water being directed into the karst aquifer. Currently, no policies exist specifically to provide water quality protections to karst environments. This study utilized a combination of karst stormwater quality data, along with survey data collected from MS4 Phase II communities, and an analysis of current federal, local, and state water quality regulations, to assess the need for karst-specific water quality regulations. Water quality data indicate that significant levels of contamination are mobilized during storm events, and often are directed into the karst system via Class V injection wells. Survey data collected from MS4 stakeholders in the karst regions of Kentucky indicate stakeholders are generally unable to explain local karst regulations or the steps taken to develop them. This confusion comes in part from insufficient progress on evaluation criteria available for the MS4 Minimum Control Measures (MCMs). Karst waters are often placed into the legal “gray zone” due in part to differences in definitions of key terms in state and federal regulations. This study recommends the development of regulations specific to karst waters at the state and federal levels through either the adaptation of existing or creation of new policies, which place an emphasis on the integration of water quality monitoring and karst education.

Numerous studies have analyzed isotopic variation of meteoric and dripwater in karst environments for paleoclimate reconstructions or aquifer recharge capacity. What is poorly understood is how the isotopic signal of δ18O and δ2H is transferred through the hydrologic cycle based upon storm type, frequency, intensity, and teleconnection activity in the tropical karst areas. At Harrison’s Cave, Barbados, a Hobo Onset event data logger was attached to a tipping bucket rain gauge to count the tips and record the total rainfall every 10 minutes. In the cave a Hobo data logger was used to record relative humidity and temperature at 10-minute intervals. Rainwater, dripwater, and stream water samples were collected at a weekly resolution and refrigerated before sample analysis. The study period was from July, 2012 to October, 2013, with data from the data loggers only until June, 2013 due to inability to reach the study site. The samples were analyzed using the Picarro Cavity Ring Down Spectroscopy Unit-Water L1102-I through laboratories at the University of Kentucky and the University of Utah. The samples were reported in per mil and calibrated. The teleconnection (NAO, AMO, and ENSO) and other atmospheric data were obtained from the Climate Prediction Center or the NOAA Earth System Research Laboratory-Physical Sciences Division. The weekly isotope signatures were linearly regressed against total rainfall for Harrison’s Cave and surface temperature with no statistically significant correlation, indicating the amount effect was not present at a weekly resolution. The amountweighted precipitation δ18O values were calculated on a monthly basis and compared to TRMM monthly rainfall and island-wide monthly rainfall, and a statistically significant negative correlation was found between both datasets. This confirmed that the amount effect dominates the island’s rainfall isotopic signature at a monthly resolution, and that specific atmospheric influences represented in weekly rainfall were less influential on a weekly basis. It is hypothesized that the variation in weekly rainfall is due to quick initiating, rain-out, and dissipation of convective storm systems over the island. In terms of evaporative influences, the samples do not deviate much from the Global Meteoric Water Line (GMWL), indicating minimal evaporation, which is typical for tropical locations. When the d-excess parameters were calculated, there were distinct variations with minimal evaporation occurring in the 2013 calendar year. This is attributed to coastal storm formation in the tropics.

Station siting, exposure, instrumentation, and time of observations influence longterm climatic records. This thesis compared and analyzed temperature data from four Kentucky Mesonet stations located in Fayette (LXGN), Franklin (LSML), Clark (WNCH), and Bullitt (CRMT) counties to two nearby Automated Surface Observation Systems (ASOS) stations in Kentucky. The ASOS stations are located at Louisville International Airport (Standiford Field - KSDF) and at Lexington Airport (Blue Grass Field - KLEX). The null hypothesis states that there is no significant difference in temperature measurements between the two types of stations. To quantify the differences in temperature measurements, geoprofiles and the following statistical procedures were used: coefficient of determination (R2), coefficient of efficiency (E), index of agreement (d), root mean square error (RMSE), and mean absolute error (MAE). Geoprofiles were developed using GIS, and take into account elevation, slope, hillshading, land use, and aspect for each site to help better understand the influence of local topography. It was found that temperature differences could be related to the advancement of weather patterns, vegetation growth and decay, and changes in the landscape at the stations. KSDF consistently recorded higher temperatures than those at CRMT. The positive bias ranged between 0.27 and 2.41 ºC during the time period of September 2009 to August 2010. KLEX was found to be warmer or cooler, with temperature differences that ranged from -1.42 to 0.22 ºC for LXGN, LSML, and WNCH. The index of agreement at KSDF for mean hourly temperatures, when compared to the Bullitt County mesonet station, ranged from 0.88 to 0.99. Meanwhile, the index of agreement at KLEX was 0.96 to 1.00 when compared to the Franklin, Fayette, and Clark mesonet stations. KLEX recorded temperatures that were higher or lower compared to the Franklin, Fayette, and Clark mesonet stations. At the seasonal scale, fall and summer showed larger differences between the Mesonet and ASOS observations. KSDF consistently recorded higher temperatures ranging up to 2.41 °C during the summer. The index of agreement at KSDF in the fall, when compared to the Bullitt County mesonet station average temperatures, ranged from 0.89 to 0.95, while in the summer it was 0.88 to 0.96. The d index indicates a good agreement between ASOS and mesonet stations in winter. KLEX indicates that the index of agreement, RMSE, and MAE are best during winter for all three stations, while in the fall and summer the agreement was not as strong when compared to the Franklin, Fayette, and Clark mesonet stations. In summary, results indicate that the Kentucky Mesonet and ASOS temperature measurements show significant differences throughout the year; therefore, the alternative hypothesis is accepted. These differences are attributed to biases associated with ASOS observations, nearby artificial sources of heating, equipment/maintenance procedures, and land use and land cover at the site.

Orientador: Cláudio Antonio Di Mauro / Banca: José Mariano Caccia Gouveia / Banca: Ana Paula Marques Ramos / Resumo: Este trabalho buscou identificar áreas para restauração ecológica dentro dos limites da UGRHI 22, localizada no Pontal do Paranapanema, na região oeste do Estado de São Paulo, Brasil. Essa região possui baixos índices de cobertura vegetal nativa, e, diante desse cenário que pode ocasionar desequilíbrio ambiental com prejuízo às atividades humanas e também devido às obrigações previstas em leis, faz-se necessário a definição de áreas nas quais as ações de restauração ecológica devem acontecer com prioridade. Para tanto, utilizou-se a metodologia de Combinação Linear Ponderada, em que as variáveis escolhidas são combinadas, atribuindo-se pesos para cada uma delas de forma a se obter o resultado final. Foram utilizados como fontes de informação e análise os dados de Fragilidade Natural à Erosão, Vulnerabilidade Natural dos Aquíferos à Poluição, Áreas de Preservação Permanente, Inventário Florestal, Conectividade do Estado de São Paulo, Unidades de Conservação e Áreas declaradas como prioritárias por outros instrumentos e definição dos pesos para as variáveis utilizadas foi feita a partir de uma matriz AHP (Analytic Hierarchy Process). Num primeiro momento, os dados foram combinados, gerando uma hierarquização em cinco classes, e partir dessa, foram destacadas as áreas com extensão superior a 5 hectares e que estivesse na classe de maior prioridade. Os resultados mostraram que há áreas prioritárias por toda extensão da UGRHI 22, com destaque para as APPs de forma geral e para as ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work aimed to identify areas for ecological restoration into the of UGRHI 22, located in Pontal do Paranapanema, in the western of the São Paulo State, Brazil. This region has low indices of native vegetation cover and, in face of this scenario that can cause environmental imbalance and affect human activities and also due to legal obligations, it is necessary to define areas in which ecological restorations actions must take place prioritarily. To achieve the results, the Weighted Linear Combination methodology was used, which means that the chosen variables are combined, and weights were assigned for each one of that. The definition of these weights was made by the application of and AHP (Analytic Hierarchy Process) matrix and the data used as sources of information and to the analysis in this work were: Natural Fragility to Erosion, Natural Pollution Aquifer Vulnerability, Permanent Protection Area, Forest Inventory, Connectivity from the São Paulo State, Conservation Units and Areas that were declared as priority by other instruments. At first, the data were combined in order to generate a five classes hierarchy map, and then, the areas within the highest priority class and with extension larger than 5 hectares were selected. The final results showed that are priority areas throughout the extension of the UGRHI 22, with emphasis on the Permanent Protected Areas and the UPHs Right Margin of Lower Paranapanema, Tributaries of Parana River and Santo Anastacio. It was co... (Complete abstract click electronic access below) / Mestre

Orientador: Anderson Luis Hebling Christofoletti / Banca: Thiago Salomão de Azevedo / Banca: Andreia Mendinilha Pancher / Banca: Jozrael Henriques Rezende / Banca: Sylvio Luiz Andreozzi / Resumo: A disponibilidade da água é influenciada pelo comportamento sistêmico do ciclo hidrológico, do qual a vazão, a precipitação e a cobertura vegetal são importantes elementos. Devido às suas características espaciais, a bacia hidrográfica constitui uma unidade geográfica adequada para a realização de estudos ambientais e hidrológicos. As ferramentas de geoprocessamento forneceram suporte metodológico à realização destes estudos, facilitando a obtenção, a organização e a análise espacial. Esta tese analisou a relação entre as variáveis vazão, precipitação, e a densidade da cobertura vegetal, estimada através do índice de vegetação da diferença normalizada, (IVDN), para as sub-bacias hidrográficas dos rios Jacaré-Pepira e Jaú (SP). Também objetivou verificar a viabilidade do uso do IVDN como subsídio à gestão ambiental de bacias hidrográficas. Os resultados mostraram que existe correlação entre as variáveis precipitação, vazão e o IVDN, utilizado como um indicativo das características da cobertura vegetal. Esses resultados indicaram que as vazões médias e mínimas apresentaram maior correlação com o IVDN. Considerando os anos padrão climáticos, secos, chuvosos e habituais, foi possível perceber que nos anos secos esta correlação ficou mais evidente reforçando a compreensão de que maiores densidades de cobertura vegetal aumentam a infiltração e reduzem o escoamento superficial, garantindo uma maior disponibilidade de água para as demandas socioambientais locais. A dinâmica espaço-te... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The systemic behavior of the hydrological cycle, mainly flow, precipitation and vegetation cover influence the availability of water. The watershed is the appropriate geographic unit for environmental and hydrological studies. Geographic Information Systems (GIS), and remote sensing, helping to carry out hydrological studies, making it easier to obtain, organize, and analyze data. The objective of this research was to characterize the main environmental aspects and analyze the relation among flow rate, rainfall, and the vegetation cover variables, estimated by the normalized difference vegetation index (NDVI), for the sub-basins of the Jacaré-Pepira and Jaú rivers (SP). It was also possible to check the viability to use NDVI to manage the environmental conditions of watershed. These results indicated that the average and minimum flows are the variables that showed the highest correlation with the NDVI in both areas. In the dry standard years, the correlation between the IVDN and the flow were more evident. This situation showed that greater intensities of vegetal cover intensify the infiltration and reduce the surface runoff, offering a greater availability of water for the local socio-environmental processes. The dynamics of land use in Jacaré-Pepira was less intense and characterized mainly by pasture and silviculture that do not require short crop cycles. While in Jaú the dynamics were more intense, mainly to the influence of sugarcane cultivation, which presents short cro... (Complete abstract click electronic access below) / Doutor

The production system in Brazil has been increasingly consolidated in the global circuit of food and grain production. The measures promoted by the Brazilian managers during the second half of the 20th century facilitated the expansion of the agricultural frontier, creating proper territories for the development of this economic activity. Thus, the region comprising the Savanna bioma received a big part of the public policies developed as a way of enabling the increase of the agricultural circuit throughout the Brazilian territory. Moreover, this expansion has been accompanied by strong processes of spatial transformations in a considerable part of Brazil, which causes a very accentuated change in the natural and social environments of the places directly involved with this economic activity. In the Northeast, for example, the state of Piauí was included in this organizational logic of the world market at the end of the last century, as this condition has contributed to the new socioenvironmental organizations that have promoted conflict in local ecosystems. Thus, this paper aims at analyzing the environmental dynamics derived from the agricultural expansion that led to the transformation of the landscape in the municipalities of Piauí cerrado, which triggered environmental impacts. Thus, the methodology used in this study is divided into three stages: the first stage is the cabinet one, which involves the bibliographic and cartographic surveys and images. The second stage corresponds to the field to collect the primary data and the photographic records, and the third and last stage corresponds to the synthesis which is the moment of analysis of the results, of the maps that confirm the hypothesis. We also emphasize that the theoretical-methodological model used in the research is the GTP, ie Geosystem, Territory, Landscape, proposed by Bertrand (1971), which provides an understanding of the object from a systemic and inclusive view of all physical and anthropogenic elements that constitute the geographic space, moreover, one can more closely get involved with the relationship between society and nature. Thus, the analysis has concluded that the appropriation of the Piauiense space by the modern agriculture has contributed to diversify and organize several territories of production of grain or small settlements, which have provided the emergence of various social environments very different from each other not only in countryside but also in the city. Thus, the expansion of trade, the splitting of the urban zone into rich and poor areas, the lack of sanitation, the poor accommodation of the urban waste, the releasing of sewage into water sources, the exploitation of minerals, among other aspects, are the main conflicts identified in the surveyed area, which promote, at every moment, dynamics in the local settings. / O sistema produtivo no Brasil vem se consolidando cada dia mais no circuito mundial de produção de alimentos e grãos. As medidas promovidas pelos gestores brasileiros, durante a segunda metade do século XX, foram dando facilidades para a expansão da fronteira agrícola, criando territórios próprios para o desenvolvimento dessa atividade econômica. Assim, a região que compreende o bioma Cerrado recebeu grande parte das políticas públicas elaboradas como meio de viabilizar o incremento do circuito agrícola por todo o território brasileiro. Ademais, essa expansão vem sendo acompanhada de fortes processos de transformações espaciais em boa parte do Brasil, a qual provoca mudança muito acentuada nos ambientes naturais e sociais dos lugares envolvidos diretamente com a atividade econômica. Na região Nordeste, por exemplo, o estado do Piauí passou a integrar esta lógica de organização do mercado mundial, no final do século passado, pois tal condição tem contribuído para as novas organizações socioambientais, que têm promovido conflitos nos ecossistemas locais. Desse modo, este trabalho tem como objetivo geral analisar as dinâmicas ambientais derivadas da expansão da fronteira agrícola que levaram à transformação da paisagem nos municípios do cerrado piauiense que desencadearam impactos socioambientais. Dessa forma, a metodologia utilizada neste estudo está dividida em três etapas: a primeira etapa é a de gabinete a qual envolve os levantamentos bibliográficos, cartográficos e imagens. A segunda etapa corresponde ao campo para coletar os dados primários e registros fotográficos, e a terceira e última etapa corresponde à síntese que constitui o momento de análises dos resultados, dos mapas que comprovam a hipótese. Destacamos também que o modelo teórico-metodológico utilizado na pesquisa é o GTP, ou seja, Geossistema, Território, Paisagem, proposto por Bertrand (1971), o qual proporciona um entendimento do objeto a partir de uma visão sistêmica e integradora de todos os elementos físicos e antrópicos que compõem o espaço geográfico, outrossim, pode-se envolver de maneira mais próxima a relação da sociedade com a natureza. Assim, a análise concluiu que a apropriação do espaço piauiense pela agricultura moderna vem contribuindo para diversificar e organizar vários territórios de produção seja de grãos ou em pequenos assentamentos, os quais têm proporcionado o surgimento de vários ambientes sociais bem distintos uns dos outros não só no campo como na cidade. Assim, a expansão do comércio; a divisão da zona urbana em áreas ricas e pobres; a falta de saneamento básico; a má acomodação do lixo urbano; lançamento de esgotos em mananciais hídricos; a exploração de minerais, dentre outros aspectos, constituem os principais conflitos identificados na área pesquisada que promovem, a cada momento, dinâmicas nos ambientes locais.

Orientador: Marcos César Ferreira / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-25T17:26:57Z (GMT). No. of bitstreams: 1 Rodrigues_MarcoAurelio_D.pdf: 11675716 bytes, checksum: d624e972d5336621b3e58137d9403388 (MD5) Previous issue date: 2014 / Resumo: O estado do Acre possui superfície de 164.079,87 km², equivalendo a 4,26% da região norte do país e 1,92% do território nacional. Localiza-se no extremo sudoeste da Amazônia Brasileira, com limites por fronteiras internacionais com Peru e Bolívia, e com os estados do Amazonas e Rondônia. Sua população totaliza 733.559 habitantes, distribuídos em 22 municípios e área desmatada de 20.234 km2, ou seja, 12,33% do estado e 2,72% da Amazônia Brasileira. O estado possui 45,66% de seu território destinado às unidades de conservação e terras indígenas. Desde 1999 o estado vem desenvolvendo o programa estadual do zoneamento ecológico econômico (ZEE). O objetivo geral da pesquisa foi avaliar o papel do zoneamento ecológico econômico na dinâmica espacial do desmatamento no estado do Acre no período de 1999 a 2010. Entre os objetivos específicos estão elaborar material cartográfico com a dinâmica espacial do desmatamento nas bacias hidrográficas, zonas de gestão territorial do ZEE, unidades fundiárias, municípios e áreas de influência das rodovias BR-364 e BR-317 no período de 1999 a 2010, avaliar os efeitos da formação dos eixos de integração e corredores rodoviários na dinâmica espacial do desmatamento e avaliar a contribuição do zoneamento ecológico econômico para as melhorias das condições socioeconômicas no estado. A metodologia adotada consistiu na análise das relações espaciais através de relatórios de consulta espacial, gráficos e mapas gerados pelo sistema de informações geográficas; elaboração dos mapas temáticos utilizando o ArcGIS 9.3; levantamento e análise de dados de desmatamento do Projeto PRODES/INPE; levantamento e análise de dados socioeconômicos baseados nos indicadores produto interno bruto, índice de desenvolvimento humano e geração de emprego e renda, utilizando informações do IBGE, PNUD, SEPLAN Acre, programa estadual do ZEE, MDS e bibliografia disponível referente à área de estudo e temas abordados na pesquisa. Os principais resultados obtidos foram à elaboração da material cartográfico por temas contendo a análise espacial do desmatamento entre 1999 e 2010, a avaliação das mudanças socioeconômicas ocorridas no período e a análise do papel do ZEE Acre nesse contexto / Abstract: The state of Acre has surface of 164,079.87 km², equivalent to 4.26% of country¿s northern region and 1.92% of national territory. It is located in the extreme southwest of Brazilian Amazon, with limits by international borders with Peru and Bolivia, and states of Amazonas and Rondônia. The population totals 733,559 inhabitants, distributed in 22 municipalities and its deforested area totals 20,234 km2, representing 12.31% of state and 2.72% of Brazilian Amazon. The state owns 45.66% of its territory aimed at conservation units and indigenous lands. Since 1999 this state has been developing the state program of economic ecological zoning (EEZ). The overall objective of the research was to evaluate the role of EEZ in deforestation¿s spatial dynamic in Acre¿s state between 1999 and 2010. Among specific objectives are: elaborate cartographic material of deforestation¿s spatial dynamics in watersheds, EEZ's land management areas, land units, municipalities, influence areas of road BR-364 and BR-317 in period of 1999-2010; evaluate the effects of formation of integration axes and road corridors in deforestation¿s spatial dynamic; measure EEZ contribution for socioeconomic conditions in state. The methodology consisted in the analysis of spatial relationships through spatial query reports, graphs and maps from Geographic Information System (GIS); elaborate thematic maps using ArcGIS 9.3; research and analysis of deforestation data through database PRODES Project from INPE; research and analysis of socioeconomic data based on the following indicators: GDP, Human Development Index and generation of employment and income, using information from IBGE, PNUD, Acre SEPLAN, EEZ state program and MDS and available literature related to the field of study and topics covered in research. The main results were thematic cartographic material with deforestation¿s spatial dynamics between 1999 and 2010; assessment of socioeconomic changes in the period and analyze role of EEZ Acre in this context / Doutorado / Análise Ambiental e Dinâmica Territorial / Doutor em Geografia

La majorité des espèces cultivées en Europe (environ 84 %) nécessitent le service de pollinisation pour produire. Depuis plusieurs années, un important déclin des pollinisateurs est observé. Les populations d’abeilles domestiques, partie intégrante de l’agrobiodiversité, sont des bio-indicateurs sensibles de l’état de l’environnement agricole. Celles-ci sont aujourd’hui affectées par des mortalités importantes. Les interactions entre pesticides et pathogènes sont habituellement évoquées comme causes principales de ces mortalités. Cependant au sein de ces agropaysages, la perte de ressources trophiques en quantité et en diversité contribue également à l’affaiblissement des colonies. La qualité et les quantités de ressources trophiques disponibles dans le paysage influencent également leur activité de ponte et leur dynamique de développement. Au regard de ce contexte, cette thèse vise à analyser les interactions entre différents types de structures paysagères situées dans le département du Gers (32, France) et l’évolution des traits d’histoire de vie des colonies d’abeilles domestiques du genre Apis mellifera L. Elle questionne notamment le rôle de la composante ligneuse dans l’apport de ressources trophiques et ses repercussions sur l’évolution des traits d’histoire de vie. L’approche méthodologique développée consiste (i) en une analyse de l’organisation spatiale des six mosaïques paysagères différenciées par un gradient de présence de ligneux, (ii) en un suivi phénologique des ressources floristiques d’intérêt nectarifère et pollinifère, (iii) en un suivi de la dynamique de développement de 43 colonies observées durant deux ans (2010 et 2011) et (iv) en une analyse des strategies de butinage. Les résultats montrent la présence d’une grande diversité d’espèces floristiques d’intérêt nectarifère et pollinifère en contexte agricole gersois (200). Les ligneux constituent la seule sous-unité fonctionnelle permettant un apport conséquent et pérenne de ressources floristiques, tout au long de la saison en complément des cultures. La composante ligneuse et les surfaces cultivées (Brassica napus et Helianthus annuus) constituent les deux sous-unités les plus mobilisées pour la collecte de nectar. Les ligneux sont particulièrement recherchés au cours des périodes prévernale et vernale (première période) notamment au sein des structures paysagères fermées. La fluctuation des ressources floristiques disponibles impacte plus fortement le développement des colonies au sein des structures paysagères ouvertes que fermées. En effet, sur ces derniers, les ligneux permettent d’atténuer ces impacts notamment en période de disette, rendant les colonies plus résilientes. / Most of the cultivated plants in Europe (84% overall) need pollinators to produce. For several decades, a significant decline in pollinating insects is observed. Honeybees belong to associated agrobiodiversity and are sensitive bio-indicators in agricultural landscapes. They are particularly affected by these losses. Usually, interactions between pesticides and pathogens are seen as the main causes of pollinator populations’ collapse. However, the qualitative and quantitative depletion of food resources in such agricultural landscapes also contribute to the high mortality rates. The spawning activity of the colony’s queen and the metabolic balance of the colony are influenced by the quantity and the quality of plant resources in the landscape. This PhD thesis focuses on the interactions between landscapes structures and honeybees life traits’ evolution in the Gers agricultural department (France). It aims to assess the woody component’s role in supplying trophic resources and its repercussions on the evolution of life traits. The methodology consists (i) in a spatial organization analysis of six landscape mosaics, differentiated by an openess gradient based on the percentage of the woody component cover, (ii) a phenological monitoring of plant resources with pollen and nectar interests, (iii) a monitoring of 43 colonies’ life history traits during two years (2010 and 2011) and (iv) in an analysis of foraging strategies. Results reveal a wide diversity of plant species with nectar and pollen interest in the Gers agricultural context (200). Woody component is the only functional sub-unity which enables a significant and lasting supply of plant resources, during the all season, as additional resources to those of crops. Woody component and cultivated lands (Brassica napus and Helianthus annuus) are the most mobilized sub-unities for nectar gathering. Woody component is particularly looked for in prevernal and vernal periods (first period), above all in closed landscape structures. Variations of available plant resources impact colonies’ development more in open landscape structures than in closed ones. Indeed, in closed landscape structures, woody component enables to reduce consequences, especially in scarcity period, and make colonies more resilient.