Estudos taxonômicos, filogenéticos e biogeográficos em Aechmea (Bromeliaceae)

Understanding evolutionary and ecological processes and patterns of Atlantic Forest species could help us to characterize the forces responsibles by biodiversity in the region. As example are the processes responsible by disjunct distribution patterns between Atlantic and Amazon forests. Therefore, the main aim of this work was understand process which allows disjunct distribution patterns in some species of Aechmea and diversification of Aechmea subg. Chevaliera. The results were summarized in eight papers organized in three parts on this thesis. In the first one, a taxonomical approach gave support to subsequents studies. Thus, the genus Aechmea is represented in Atlantic Forest at North of Sao Francisco River by 27 species and three of them are disjunct between Atlantic and Amazon Forest. Moreover, it was possible describing one new taxon to the subgenus Chevaliera. In the second part, a study about the sampling sufficiency of species was made, which allow conclude that good representation of environmental spaces of some species are not related to number of samples and forest lodge influences the quality of information about habitat of species. As consequence two species with sampling sufficiency and disjunct distribution were selected to analyse the effect of climatic changes in creating dispersion corridors. In past climatic scenarios the main connection between Northeastern Atlantic Forest and Amazon Forest was by coastal region of Brazilian Northeast. This results hightlight the importance of east coast as possible corridor between the two forest in climatic changes that increased pluviosity and humidity in South America instead the connection throughout caatinga, which is proposed in literature. In the last part, the evolution of subgenus Chevaliera was studied. A dated molecular phylogeny (ETS, matK e phyC) and studies of morphological and niche evolution revealed that the subgenus is polyphyletic. The Amazonian species previously classified as subg. Chevaliera emerges in distinct moments of evolutionary history of Bromelioideae. Two groups emerged gathering the majority of atlantic species. The first one included seven species related to Aechmea multilora complex. The second one gathered eleven species that form the restrict concept of subg. Chevaliera, named here as A. sphaerocephala group. We proposed tranfer to a new genus called Gravatarum all species related to A. multiflora complex. Morphological analyses show that Gravatarum and A. sphaerocephala group converg in body volume and growth form and in inflorescence aspect. However, they differentiate each other by floral bracts margins and petal color. The study of evolutionary dinamics of both groups shows that they share the same morphological and geographical spaces, but they had differents dynamics of occupation of Atlantic Forest, dispersion in available habitats and evolution in environmental spaces in the last three millions of years.