Floristic diversity of African and South American inselbergs: a comparative analysis

Inselbergs are isolated rock outcrops that rise abruptly above the surrounding plains. Granitic and gneissic inselbergs are geologically and geo-morphologically old and are geographically widespread. Inselbergs form micro-climatically and edaphically dry growth sites that bear a highly specialized vegetation. Based on physiognomic criteria a number of habitat types can be distinguished (e.g. ephemeral flush vegetation, monocotyledonous mats, rock pools) that are widespread on inselbergs. In Africa, the eastern and southeastern part of the continent support the species-richest inselbergs. In particular in the savanna biomes the ephemeral flush vegetation forms the species-richest habitat. In South America, southern Venezuela and the Brazilian Mata Atlantica region are important centers of diversity for inselberg plant communities.