Phytogeographical meta-analysis of the caatinga biome

Abstract

This project aims to assess biogeographic patterns in the Caatinga biome. An extensive bibliographic survey was made in order to collect floristic and phytosociological papers made in the Brazilian Caatinga. These surveys will be used for the preparation of the thesis' chapters. The first chapter will address sampling in the Caatinga and methodological subjects, such as sampling effort by state, phytosociological methods used and other topics related to sampling. The second chapter will evaluate the differences between Caatinga of crystalline and sedimentary areas, comparing the life form spectra of Raunkiaer in each area to test differences in subtypes of Caatinga and checking for structural and functional differences in the biological communities of each plant community. The third chapter (to be developed during the interchange, in partnership with researchers of the Royal Botanic Gardens, Kew) will assess the overall diversity of phanerogams in the Caatinga. A checklist of plants will be produced, and the floras of the crystalline and sedimentary Caatingas will be contrasted. We will also evaluate the partition of flora between the woody and herbaceous components of plant communities, since traditionally only woody plants have been studied, underestimating the total richness of the biome. The fourth chapter aim to compare the flora of the Caatinga with the flora of the South American flora and global levels in genus and family levels, using the Kew's global database of genera and families plant distribution. Finally, botanical names will be standardized and we will address the problem of synonymy during the interchange at Kew. When the standardized checklist of Caatinga species is finished, our last chapter will be possible. The last chapter will assess the general patterns of species distribution in crystalline and sedimentary Caatingas. In order to do this, a matrix of species presence/absence must be built and each species must be identified by just one name unequivocally. In order to make this matrix feasible, the project of standardization of names and the production of the checklist (to be developed in Kew) is essential. The pool of species of Caatinga will then be subjected to multivariate analysis in order to assess the general patterns of species distribution. We wil then discuss to which extent the Caatingas of crystalline and sedimentary areas are really distinct. (AU)