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Improved knowledge of landscape seasonal variations and phenology at the regional scale is needed for carbon and water flux studies, and biogeochemical, hydrological, and climate models. Amazon vegetation mechanisms and dynamics controlling biosphere-atmosphere interactions are not entirely understood. To better understand these processes, vegetation photosynthetic activity and canopy water and temperature dynamics were analyzed over various types of vegetation in Amazon using satellite data from the Terra-Moderate Resolution Imaging Spectroradiometer (MODIS). The objectives of this dissertation were to 1) assess the spatial and temporal variations of satellite data over the Amazon as a function of vegetation physiognomies for monitoring and discrimination, 2) investigate seasonal vegetation photosynthetic activity and phenology across the forest-cerrado ecotone and conversion areas, and 3) investigate seasonal variations of satellite-based canopy water and land surface temperature in relation to photosynthetic activity over the Amazon basin.The results of this study showed the highly diverse and complex cerrado biome and associated cerrado conversions could be monitored and analyzed with MODIS vegetation index (VI) time series data. The MODIS enhanced vegetation index (EVI) seasonal profiles were found useful in characterizing the spatial and temporal variability in landscape phenology across a climatic gradient of rainfall and sunlight conditions through the rainforest-cerrado ecotone. Significant trends in landscape phenology were observed across the different biomes with strong seasonal shifts resulting from differences in vegetation physiognomic responses to rainfall and sunlight. We also found unique seasonal and temporal patterns of the land surface water index (LSWI) and land surface temperature (LST), which in combination with the EVI provided improved information for monitoring the seasonal ecosystem dynamics of the Amazon rainforest, cerrado, ecotone, and conversion areas. In conclusion, satellite-based, regional scale studies were found to aid in understanding land surface processes and mechanisms at the ecosystem level, providing a "big picture" of landscape dynamics. Coupling this with ground, in-situ measurements, such as from flux towers, can greatly improve the estimation of carbon and water fluxes, and our understanding of the biogeochemistry and climate in very dynamic and changing landscapes.

The Amazon represents more than half of the surviving tropical forest on Earth. However, despite its vast size and diversity, habitat loss is an increasing threat due to the growth of economic activities and infrastructure projects. Carnivores play an important role in reducing herbivore numbers through predation, thereby reducing the risk of over browsing and are particularly susceptible to habitat loss and fragmentation due to their large area requirements, low densities, and slow population growth. Altering herbivore communities via a change in carnivore density and habitat loss may change plant diversity by altering seed dispersal, and seed and seedling survival. The Madeira-Purus interfluvial plain in Brazil is a pristine and yet understudied part of the Amazon. I studied environmental factors affecting occupancy and detection of carnivores and herbivores in the Madeira-Purus interfluvial plain Amazonas state, Brazil. During 2010-12 remote cameras were used to investigate patterns of site occupancy and detection probabilities, as affected by habitat and anthropogenic influences, for several terrestrial mammal groups. Site occupancy and detection varied for all species groups across land protections types. Medium felids and peccaries showed a sharp decline in occupancy from unprotected lands to state-protected sites with the highest occupancy on the federally-protected site. Brocket deer increased in occupancy from unprotected to state-protected lands, and from state-protected to federally-protected lands. Large felid occupancy, however, was exactly the opposite, with the lowest occupancy at the federally-protected site. Species richness at camera sites was the most important covariate, positively influencing occupancy in all species groups. This helps inform wildlife management by providing suggestions to improve future occupancy studies and support for maintaining protected areas for the persistence of viable mammal populations. I found occupancy of many species groups (i.e. peccaries, medium felids and medium rodents) were lowest on state-protected land. Species richness was also lowest on state-protected land, implying a depletion of herbivore and carnivore species in that area, which may be due to local foraging and hunting of forest resources by humans. I recommend stricter laws and enforcement to limit the harvest of forest fruits and nuts and illegal hunting. Repaving local highways will likely increase human influence in these areas and increase pressure on forest resources.

This thesis studies the forest labour process of seringueiros (rubber tappers) in the contemporary Amazon. It investigates labour processes from a Marxist anthropological perspective, focusing on value and exploitation on the capitalist periphery. The analysis is supported by an ethnographic description of contemporary seringais (rubber estates) in the State of Acre, where I was born. This work is organised in three independent parts. Chapters 1 to 4 constitute a study of the local history of rubber estates and their interface with world and national history. They deal with the the cycle of expansion and decline of the rubber trade on the Upper Jurua region of Acre (1870-1943), the renewed prosperity of the extractive economy in the post-war period (1943-1980) and the conflicts between rubber patrons (patroes) and tappers during the last decade (1980-1990). I conclude that the contemporary rubber estate system was a product of regional Brazilian politics rather than a response to the imperatives of the world economy. It developed into its present form as a result of Brazilian State economic policies, which favoured and subsidised a technologically stagnant regional elite in an area marginal to the world market. Another conclusion holds that a forest peasantry with a highly-diversified local economy developed on the contemporary estates. This forest peasantry possesses its own stakes in the forest economy. It is not simply a proletariat forced to remain in the forest and supply the world or national market by virtue of debts. Chapters 5 and 6 describe in detail the trade-post system and the debt system on the basis of field work done on the Tejo River Valley. I describe the trade-post institution as based on the monopoly of natural resources and of trade, supported by state agencies, extracting rents and mercantile profits from a population of rubber tappers operating independent economic units in the heart of the forest. I argue that system is unable to control the forest labour process. I also interpret debt relations as a consequence of the extractive character of the forest economy and not as an imposition of trade-posts. Chapters 7 through 10 proposes the model of a forest house economy, including its social groups, its use of the natural resources, its labour process and its overall working. Far from specialised rubber producers, the rubber tappers' forest house economy is characterised in technical terms by the amplitude of forest niches they occupy (including hunting, collecting and cultivation). The technological and social patterns of this economy possesses ecological and technological characteristics that are essentially different from non-forest peasant economies ("settler" economies in the Amazon), and also from the large-scale productive units (fazendas). My argument favours the inclusion of the tappers' extensive economic strategies in the forest as part of a wider development policy.

Thesis (Ph. D.)--University of Florida, 2005. / Title from title page of source document. Document formatted into pages; contains 326 pages. Includes vita. Includes bibliographical references.

The primary objective of this work is to investigate the potential of utilizing Hadoop and Amazon Redshift in the Amazon Web Services ("AWS") cloud, in order to design and implement a data warehouse, the efficacy of which will be tested afterwards. Contributions of this work include: documenting the technologies in the AWS cloud in Czech, demonstration of the design and performance tests of the data warehouse and the ETL part. Another considerable benefit is the added value to the company for whom the project was designed, and which is currently using the output of the project.

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Amazonia contains the largest expanse of tropical forest in the world and is globally significant as a store of carbon, a regulator of climate and an area of high species diversity. The ability of the Amazonian forests to maintain these important ecological functions is however, increasingly under question in light of recent predictions of climate change. There is currently significant uncertainty in model predictions of how Amazonian forests will respond to predicted future climate change. This thesis reports the finding of two field studies, targeted at understanding the responses of two tropical forest carbon fluxes which are poorly simulated in vegetation models, and two modelling studies, which aim to better quantify uncertainty on model predictions of the effects of current and future climate change on the ecological function of Amazonian forests. The responses of forests to varying magnitudes of seasonal changes in climate which occur across Amazonia can give an important insight into the sensitivity of these forests to climate perturbations and changes. Testing the sensitivity of an Amazonian forest in Tambopata, Peru, to seasonal variations in precipitation and temperature, I find that the stem diameter growth of tropical trees is more sensitive to water availability than temperature changes. The vulnerability of trees to reduced soil water varied between tree classes with different functional traits, including wood density, tree height, tree diameter and tree growth rate. Similarly, I find that the respiration flux from tropical dead wood, at a second site in French Guiana, is highly sensitive to variations in water content. I show that these variations in respiration fluxes can be modelled successfully using seasonal variations in soil water content. To date there are few studies which have comprehensively tested vegetation models using ecological data from Amazon forests. Using data assimilation and nine sources of ecological data I estimate the certainty with which we can parameterise a carbon cycle model to represent the effects of a strong dry season on tropical forests. Using this technique I find, that the carbon balance of Amazonian forests can be very sensitive to reductions in water availability, and that these seasonal changes need to be accurately simulated across models to correctly predict annual carbon budgets. The variability in model responses caused by differences in the way processes are structured and parameterised in vegetation models requires better quantification. Using a model inter-comparison I demonstrate that the relative sensitivity of modelled climate-vegetation feedbacks to changes in ambient air temperature and precipitation is highly variable. I find that although the models showed similar directional responses at both the leaf and canopy scale some models showed a greater sensitivity to temperature and others to drought. I therefore demonstrate the need for greater constraint on modelled responses of Amazonian forests to changes in temperature and precipitation. The impact of climate change on Amazonian forests is an important global issue, yet our knowledge is reliant on our ability to understand the uncertainties on our predictions. Using field data to evaluate and to develop model predictions is a valuable way to reduce the uncertainty associated with modelling future change. This thesis presents an investigation of how tropical forests respond to changes in climate and with what certainty we can model these changes in order to predict the response of Amazon forests to predicted future climate change.