This BioProvince (as defined by Armen Takhtajan) is based on Brazil’s Provinca de la Caatinga and includes the highlands of northeastern Brazil. It extends from Turiacu south to the southern boundary of the state of Espirito Santo. Caatinga is a term that was used by indigenous people to describe open forest or white forest. This the largest dry forest area in South America and one of the richest dry forests in the World, but much of the Caatinga also comprises open shrubby vegetation. A large part of the area has bedrock geology of Proterozoic crystalline rock overlain by Palaezoic and Mesozoic sedimentary basins, and extensive areas of Caatinga are confined to either crystalline or sedimentary intermontane depressions. Large parts of the terrain have an undulating relief, occasionally broken by inselbergs, isolated mountains and escarpments. The climate is semiarid with much potential for evapotranspiration throughout the year combined with low rainfall. Draughts are common and severe ones can last for up to five years. In fact, it is classed as one of Brazil’s most severe landscapes, and with mean annual temperature of 28°C, it is one of the hottest semiarid areas on the Planet. Nevertheless, there is rich flora with an estimated 932 vascular plants and a high level of endemism. Of the succulents and woody plants there are 18 endemic genera and about 318 endemic species (about 34% of the flora), and overall there are at least 390 endemic species and 30 endemic genera including Alvimiantha, Ameroglossum, Anamaria, Apterokarpos, Argyrovernonia, Auxemma, Barnebya, Blanchetia, Blanchetiodendron, Caatinganthus, Dizygostemon, Epostoopsis, Fraunhofera, Glischrothamnos, Godmania, Goniorrhachis, Haptocarpum, Heteranthia, Holoregmia, Hydrothrix, Macvaughia, Mattfeldanthus, Mysanthus, Neesiochloa, Piriadacus, Rayleya, Teixeiranthus and Telmatophila. The vegetation is highly variable in both structure and species composition and largely composed of succulents (mainly Cactaceae and Euphorbiaceae), thory shrubs and terrestrial bromeliads, and many species have water storage facilites. Leafless succulents such as Euphorbia phosphorea and various cacti are fully adapted to the arid environment, but other adpaptations include swollen trunks (Canvanillesia arborea and Chlorisia glaziovii) and underground storage tubers (Carica corumbaensis and Sphondias tuberosa). The former develops barrel-shaped tubers that can be 80 cm long. Other caatinga species such as the bromeliads Tillandsia recurvata and T. streptocarpa can extract water from humid air through their scale-like hairs.
The following accounts for this BioProvince have been written or will be written with particular reference to endemic and locally important species. Accounts available are displayed in green or yellow. Those displayed in red are either in the pipeline or awaiting expert contributions.
|Endemic Vascular Plant Flora|