Biodiversity of arid islands in tropical Africa: the succulents of inselbergs

Abstract

Inselbergs are isolated rock outcrops of considerable geological and geomorphological age. They occur throughout tropical and subtropical Africa and Madagascar. Microclimatically and edaphically they can be considered as arid islands even in perhumid zonobiomes. Thus they bear a flora differing almost totally from the surrounding vegetation. Succulents are amongst the characteristic elements: for the first time a short annotated systematic survey of their occurrence on inselbergs is provided with notes on the geographical distribution and the centres of diversity