Interações entre seres humanos e plantas como determinantes para montagem de comunidades vegetais da Caatinga

Abstract

The complex dynamics of ecosystems, given by the variation over time and space in biotic and abiotic conditions, has been translated by Ecology, which over time has gained strength, complexity and connectivity with several other sciences, in an incessant quest to understand the patterns that govern the abundance, composition and diversity of species. However, only recently, the role of humans began to be incorporated in explanations and predictions about these systems dynamics. Within this context, the main objective of this thesis was to understand how plant communities assemble along climatic gradients subjected to different chronic anthropic disturbances in the Brazilian semi-arid region. For this, we also seek to integrate the ecological knowledge of local human populations about the use of plant species with aspects of the Ecology of plant communities, to determine how morphological and physiological characteristics (functional traits) of plants influence the selection and use of species by local human populations. Our results reveal that species use and selection relationships have severe effects on the dynamics of socio-ecological systems. Local human populations select plant species according to important characteristics such as wood density, specific leaf area, leaf thickness. Such selection exerts a strong use pressure on the most desirable species, which can negatively affect the dynamics and resilience of the system. In this sense, the plant communities of the adult and regenerating strata are committed to development, which in turn will affect the supply of ecosystem goods and services to human societies, especially those that directly depend on these resources. The dynamics of plant communities in the Caatinga is, therefore, a complex resulting from the interaction between abiotic factors together with the influence of human beings who are agents capable of influencing the functioning of the ecosystem.