Species lists available from floristic and phytosociological studies contain important information about species distributions that are useful for making biogeographical inferences and even to evaluate conservation status of species and ecosystems. In the case of the Caatinga, this information may contribute to challenging the pre-established idea that it is a homogeneous vegetation unit. The strong relation between the substrate and the plant assemblages of the Caatinga may characterise different types of vegetation. In this way, the objective of the present study is to evaluate whether differences in the distribution of Cactaceae relate to distinctive types of substrate (sedimentary and crystalline) as much in terms of floristic richness as species density. Concomitantly, we evaluated the conservation status of the Caatinga areas studied. To obtain the data, we undertook a bibliographi...

Species lists available from floristic and phytosociological studies contain important information about species distributions that are useful for making biogeographical inferences and even to evaluate conservation status of species and ecosystems. In the case of the Caatinga, this information may contribute to challenging the pre-established idea that it is a homogeneous vegetation unit. The strong relation between the substrate and the plant assemblages of the Caatinga may characterise different types of vegetation. In this way, the objective of the present study is to evaluate whether differences in the distribution of Cactaceae relate to distinctive types of substrate (sedimentary and crystalline) as much in terms of floristic richness as species density. Concomitantly, we evaluated the conservation status of the Caatinga areas studied. To obtain the data, we undertook a bibliographi...