The biodiversity hotspot as evolutionary hot-bed: spectacular radiation of Erica in the Cape Floristic Region. Issue 1 (December 2016)

• Record Type: Journal Article
• Authors: Pirie, M.; Oliver, E.; Mugrabi de Kuppler, A.; Gehrke, B.; Le Maitre, N.; Kandziora, M.; Bellstedt, D.
• Is Part Of: BMC evolutionary biology. Volume 16:Issue 1(2016)
• Page Start: 1
• Page End: 11
• Publication Date: 2016-12
• Subjects: Biodiversity -- Cape Floristic Region -- Diversification -- Erica -- Evolution; Evolution (Biology) -- Periodicals; 576.805
• DOI: 10.1186/s12862-016-0764-3
• Languages: English
• ISSNs: 1471-2148

Abstract

Abstract Background The disproportionate species richness of the world's biodiversity hotspots could be explained by low extinction (the evolutionary "museum") and/or high speciation (the "hot-bed") models. We test these models using the largest of the species rich plant groups that characterise the botanically diverse Cape Floristic Region (CFR): the genusErica L. We generate a novel phylogenetic hypothesis informed by nuclear and plastid DNA sequences of c. 60 % of the c. 800Erica species (of which 690 are endemic to the CFR), and use this to estimate clade ages (using RELTIME; BEAST), net diversification rates (GEIGER), and shifts in rates of diversification in different areas (BAMM; MuSSE). Results The diversity ofErica species in the CFR is the result of a single radiation within the last c. 15 million years. Compared to ancestral lineages in the Palearctic, the rate of speciation accelerated across Africa and Madagascar, with a further burst of speciation within the CFR that also exceeds the net diversification rates of other Cape clades. Conclusions Erica exemplifies the "hotbed" model of assemblage through recent speciation, implying that with the advent of the modern Cape a multitude of new niches opened and were successively occupied through local species diversification.