Relative contribution of in situ speciation and immigration to species richness in selected tropical alpine regions (pie charts on the left). Blue: in situ speciation, green: colonisation, light blue: uncertainty regarding in situ speciation, light green: uncertainty about colonisation. In the right pie charts, colonisation is further decoupled into species derived from other regions with alpine-like climate (black) and species that originated by colonisation from a different biome (red). Uncertainty is indicated by grey.