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Universidade Federal de Lavras (2008)

Vulnerability of the Minas Gerais landscape to global changes : an initial step to a bottom-up approach

Barbosa, João Paulo Rodrigues Alves Delfino

Titre : Vulnerability of the Minas Gerais landscape to global changes : an initial step to a bottom-up approach

Vulnerabilidade da paisagem de Minas Gerais às mudanças globais : um passo inicial para uma abordagem tipo bottom-up

Auteur : Barbosa, João Paulo Rodrigues Alves Delfino

Université de soutenance : Universidade Federal de Lavras

Grade : Doutorado em Agronomia/Fisiologia Vegetal 2008

Résumé
In the last century, the mean air temperature in Minas Gerais increased 1.4oC and the prediction is that the value will rise to almost 3oC at the end of the present century. Together with this warming trend, alterations in the timing and amount of precipitation are also forecasted. This scenario can have an effect on the biochemical and biophysical processes of the landscape, affecting the vegetation functioning, with potential impacts over ecosystems services. This study was an initial step towards the assessment of the vulnerability of the landscape of Minas Gerais to the global changes, in a bottom-up perspective, by the evaluation of the interactions of weather variability with the functional characteristics of three ecosystems : Cerrado, Coffee plantations and eucalypt plantations, in three regions of Minas Gerais : South, West and North. To accomplish this major objective, we first characterized the spatial distribution of recent-past, present and future patterns of temperature and precipitation in Minas Gerais. Second, we integrated the weather information with fire regime data, to verify and predict the susceptibility of fire-prone vegetation to extreme events. We also examined the land cover structure in the study sites. The third step was the investigation of ecosystem functioning by remotely sensed vegetation indices, as well as the functioning at leaf level by a literature survey. Finally, we proposed insights on the assessment of the vulnerability of the landscape of Minas Gerais to drought stress, based on sensitivity of functional parameters to water availability. Although some limitations in the analytic procedure, this study could represent one of few large-spectrum surveys of climate change effects on ecosystem functioning in Minas Gerais, ranging from leaf to landscape. Moreover, we generated a database and proposed a framework based on sensitivity analysis that allowed insights on landscape vulnerability to climate changes and scaling procedures. This database can be used further in more complex simulation modeling of landscape dynamics in diverse time-space scales. The proposed framework could represent a component of the strategy to understand and anticipate the potential effects of global changes on Minas Gerais landscape.

Mots clés : Leaf traits Ecosystem functioning Land cover structure Fire regime Weather variability Extreme episodes Variabilidade climática Características foliares Funcionamento de ecossistemas Queimadas Uso da terra Eventos extremos

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Page publiée le 31 janvier 2015, mise à jour le 4 juillet 2017