The Dean and Science Faculty Research Committee invites you to a seminar on the Cape Floristic Region as part of celebrating research in the faculty. 


Many plant radiations, including that of the flora of the Cape Floristic Region (CFR), have taken place in the context of topographically complex landscapes. Where past authors working on the Cape flora have emphasized the importance of elevational gradients as stimuli for “ecological speciation” (speciation by adaptive divergence), the archipelagic configuration of the Cape Fold Mountains provides ample scope for geographically-motivated “nonecological speciation”. In this talk, I will argue that the richness of the Cape flora is the outcome of both processes. I will first characterize these, using examples from my research. Then, using data for six Cape plant lineages, I will show that speciation in the CFR occurs predominantly within elevation zones rather than along elevational gradients, that geographic isolation is stronger at high elevations than at low elevations, and that adaptive divergence is weaker at high elevations. The overall picture to emerge is that speciation mechanism in the CFR varies with elevation, with adaptionally-motivated differentiation being prevalent at low elevations, and neutral, non-adaptive divergence being more important at high elevations.