Souza, Alexandre Fadigas deSilva, Augusto César da2023-05-172023-05-172023-02-16SILVA, Augusto César da. Padrões biogeográficos e estratégias ecológicas no domínio caatinga e na diagonal seca brasileira. Orientador: Alexandre Fadigas de Souza. 2023. 250f. Tese (Doutorado em Ecologia) - Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, 2023.https://repositorio.ufrn.br/handle/123456789/52459The distribution and functioning of vegetation in seasonally dry environments, its internal structure and the organization of its functional attributes are still poorly understood. This thesis divided into three chapters aimed to understanding the organization of dominance patterns and functional structure and their main determinants in the Caatinga and Brazilian dry diagonal. The first chapter aimed to delineate subregions of dominance in the Caatinga domain, considering species abundances, and to evaluate the determinants of their spatial distribution. Sub-regions were identified and mapped, partitioning interpolated NMDS ordering axes using the “K-means” method. We used a selection of GLM models to identify the set of variables that explained bias across subregions. We identified 10 sub-regions of dominance regulated by the combined fractions of aridity, topography and soil, stability of the biome in the Pleistocene and the historical effect of indigenous activities. In the second chapter, we identified the functional strategies of the species in the Caatinga within the scope of the CSR theory and global functional spectrum. Classification of species in the Competitor, Stressotolerant and Ruderal (CSR) strategies and functional spectrum used leaf functional (leaf area, leaf dry matter content, leaf nitrogen, leaf mass per area) and structural (maximum plant height and wood density) data of the species. We used the StratFY matrix and a phylogenetic PCA to generate CSR strategies and functional correlations. In the Caatinga, 47% of the species showed a predominance of competitor-stressor strategies. Additionally, two functional groups separated species divided with large and small leaves along the functional space. Leaf attributes were determinant for the organization of functional strategies of the species in the Caatinga. In the third chapter, we tested how the relationship between current or historical environmental and human filters determines the structuring of functional attributes in the Brazilian dry diagonal (Caatinga-Cerrado-Pantanal). These relationships were identified and tested through an extended RLQ analysis. We find two functional gradients along the dry diagonal, two functional gradients related to categorical attributes of the leaf (simple and compound) fruit (dry and fleshy), and presence of latex are filtered by the elevation, soil granulometry and evapotranspiration. In this thesis we can observe that the spatial structuring patterns of abundance and their functional strategies are regulated by multiple environmental and human filters. We emphasize here the importance of leaf attributes for the organization of species strategies in the Caatinga, as well as the importance of categorical attributes of leaf, fruit and latex in the structuring of communities in the Brazilian dry diagonal.Acesso AbertoAmbientes secosAtributos funcionaisBiorregionalizaçãoTeoria CSREfeitos humanosFiltros ambientaisdoctoralThesisCNPQ::CIENCIAS BIOLOGICAS::ECOLOGIA