The causes of southern African spatial patterns in species richness: speciation, extinction and dispersal in the Danthonioideae (Poaceae)

摘要

Aim Four factors (time, dispersal, extinction and speciation) shape the differences in species richness within a clade between two regions. The southern African summer-rainfall Highveld' is less species rich than the adjacent winter-rainfall Greater Cape Floristic Region'. In many clades, this may be the result of a Cape origin of these temperate clades, with later dispersal to the cool uplands of the Highveld. We explored an alternative scenario of a widespread southern African Miocene temperate flora, which survived in the Cape. We used these four factors to seek the more likely scenario for the Danthonioideae.