ecological strategies, functional ecology, functional traits, morphoanatomical adaptations, tree ecophysiology.

Despite the renowned Amazonian forests, approximately 267,000 km² of the region is covered by natural grasslands and savanna-like formations, which remain understudied. The role of these formations in structuring

vegetation is still poorly understood, especially in the face of increasing degradation events and climate change threats to these landscapes. In this context, the first chapter of this thesis highlights that soil properties influence the functional traits and intraspecific variation of Curatella americana L. (Dilleniaceae), a typical and dominant species in Amazonian open areas, exhibiting both conservative and acquisitive strategies depending on tissue type. The second chapter addresses the structural aspects and floristic composition of four Savanna Park areas in the Amazon, aiming to estimate spatial dynamics and patterns based on phytosociological and floristic data. A total of 3,035 individuals were analyzed in 69 plots, sampling all tree species with DBH ≥ 5 cm. Overall, Amazonian savannas exhibit variations in floristic composition and diversity, with greater richness in the South and lower richness in the North, influenced by biogeographic position. The third chapter analyzed the leaf morphoanatomical adaptations and wood density of five dominant tree species in the Amazon-Cerrado transition zone, revealing coordinated conservative and acquisitive strategies between species. Morphological trait variation is primarily driven by intraspecific effects, suggesting adaptation to environmental conditions. The coexistence of these strategies underscores the functional diversity and resilience of the region to environmental change. These findings provide

insights into the ecophysiological adaptations of tree species in different Amazonian savanna contexts, their functional strategies and the role of ecological strategies in maintaining functionality in tropical ecosystems.