Worldwide geographical distribution of woody plants of the Aiuaba Ecological Station, Ceará State, Brazil

Abstract

The ‘caatinga’ biome was recently recognized as a Biosphere Reserve by UNESCO, as one of the 37 large natural regions on Earth. Nonetheless, little is known concerning its vegetation and flora and the distribution patterns of ‘caatinga’ species. Vegetation maps available recognize several vegetation formations within this biome, of which the ‘caatinga’ sensu stricto, a xeric formation, is the most extensive, especially within the so called ‘depressão sertaneja’ of Northeastern Brazil. Such vegetation covers 58% of Northeastern Brazil and 11% of the whole country (approx. 800,000 km2). Based on the floristic survey of an area in Ceará, distribution of woody species was studied, using the collections housed at EAC, IPA, K, BM, OXF, FHO, E and literature data. Some species are present only in areas of ‘caatinga’, but many of them occur also in dry forest formations throughout South and Central America. As a general rule, the distribution of the species studied in this project suggest that the caatinga can be considered as one of the nodes for migration between dry areas of South America, and that the flow of species has probably occurred in two ways, as already stated by other researchers.