Rapid and recent origin of species richness in the Cape flora of South Africa

Richardson, James E.; Weitz, Frans M.; Fay, Michael F.; Cronk, Quentin; Linder, H. P.; Reeves, Gail; Chase, Mark W.

doi:10.1038/35084067

Cited by 225 publications

(198 citation statements)

References 13 publications

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“…Using the older age estimate of 1.93 Myr for the Andean node yields a more conservative estimate of 1.93-2.78 species per Myr. However, even this minimum estimate exceeds reported species diversification rates for plants either on islands (10,23) or continents (4,6,11,26), providing the most spectacular example of explosive species diversification in plants documented to date. Low sequence divergence, lack of resolution and support, and͞or sparse taxon sampling in phylogenetic studies of other highelevation Andean plant groups (20,21,27,28) (21).…”

Section: Resultsmentioning

confidence: 58%

“…For plants, the idea that island-type diversifications are faster than mainland radiations has been hotly debated without conclusion (4,6,10,11,23,26). The exceptional rates of diversification found for high-elevation Andean plants suggest that island-like diversification driven by ecological opportunity may indeed outpace mainland-type radiations.…”

Section: Resultsmentioning

confidence: 99%

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Island radiation on a continental scale: Exceptional rates of plant diversification after uplift of the Andes

Hughes

Eastwood

2006

Proc. Natl. Acad. Sci. U.S.A.

913

903

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Species radiations provide unique insights into evolutionary processes underlying species diversification and patterns of biodiversity. To compare plant diversification over a similar time period to the recent cichlid fish radiations, which are an order of magnitude faster than documented bird, arthropod, and plant radiations, we focus on the high-altitude flora of the Andes, which is the most species-rich of any tropical mountains. Because of the recent uplift of the northern Andes, the upland environments where much of this rich endemic flora is found have been available for colonization only since the late Pliocene or Pleistocene, 2-4 million years (Myr) ago. Using DNA sequence data we identify a monophyletic group within the genus Lupinus representing 81 species endemic to the Andes. The age of this clade is estimated to be 1.18 -1.76 Myr, implying a diversification rate of 2.49 -3.72 species per Myr. This exceeds previous estimates for plants, providing the most spectacular example of explosive plant species diversification documented to date. Furthermore, it suggests that the high cichlid diversification rates are not unique. Lack of key innovations associated with the Andean Lupinus clade suggests that diversification was driven by ecological opportunities afforded by the emergence of island-like habitats after Andean uplift. Data from other genera indicate that lupines are one of a set of similarly rapid Andean plant radiations, continental in scale and island-like in stimulus, suggesting that the high-elevation Andean flora provides a system that rivals other groups, including cichlids, for understanding rapid species diversification.leguminosae ͉ Lupinus ͉ phylogeny ͉ species diversification S tudies of rapid episodes of species diversification or species radiations have provided a continuously rich source of new insights into the evolutionary processes underlying diversification and modern patterns of biodiversity for the last 150 years (1-6). A striking feature of species radiations is the discrepancy between the very high rates of species diversification reported for cichlid fish radiations in east African rift lakes and all bird, arthropod and plant radiations (2,7,8). This discrepancy has been attributed in part to the recency of the fish radiations (7). Accurate measurement of peak episodes of diversification embedded within older radiations requires fully sampled and resolved phylogenies (9). In the absence of such phylogenies, measurements of diversification rates for most radiations are less precise because they average out episodes of faster and slower speciation. Furthermore, these approaches measure net diversification rates, and the effects of extinction are not assessed. If speciation is concentrated in the early phases of radiations (3,7,10,11), this could explain the discrepancy between the exceptional rates of species diversification reported for very recent [Ͻ2 million years (Myr)] lacustrine fish and other documented bird, arthropod, or plant radiations, which are generally older (Ͼ5...

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Section: Resultsmentioning

confidence: 58%

Section: Resultsmentioning

confidence: 99%

Island radiation on a continental scale: Exceptional rates of plant diversification after uplift of the Andes

Hughes

Eastwood

2006

Proc. Natl. Acad. Sci. U.S.A.

913

903

View full text Add to dashboard Cite

show abstract

“…The phylogeny of this genus is still unknown, so the place of origin of Sebaea can not be suggested yet. Examples showed that the species richness in the Cape flora probably resulted from rapid and recent (7-8 MY) diversification (Cowling and Pressey, 2001;Richardson et al, 2001b). This might also be the case for Sebaea.…”

Section: Biogeographical Implicationsmentioning

confidence: 96%

Monophyly and relationships of the tribe Exaceae (Gentianaceae) inferred from nuclear ribosomal and chloroplast DNA sequences

Yuan

Wohlhauser

Möller

et al. 2003

Molecular Phylogenetics and Evolution

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Both chloroplast trnL (UAA) intron and nuclear ribosomal ITS sequences highly confirmed the monophyly of the tribes of the Gentianaceae defined by the recent classification, and revealed the tribe Exaceae as a basal clade just next to the basal-most lineage, the tribe Saccifolieae. Within the tribe Exaceae, Sebaea (except Sebaea madagascariensis) appeared as the most basal clade as the sister group to the rest of the tribe. The Madagascan endemic genera Gentianothamnus and Tachiadenus were very closely related to each other, together standing as sister to a clade comprising Sebaea madagascariensis, Ornichia, and Exacum. The saprophytic genus Cotylanthera nested deeply inside Exacum. Sebaea madagascariensis was shown closer to the Madagascan endemic genus Ornichia than to any other sampled Sebaea species. Exacum appeared as the most derived taxon within this tribe. The topology of the phylogenetic trees conform with the Gondwana vicariance hypothesis regarding the biogeography of Exaceae. However, no evidence for matching the older relationships within the family to the tectonic history could be corroborated with various divergence time analyses. Divergence dating estimated a post-Gondwana diverging of the Gentianaceae about 50 million years ago (MYA), and the tribe Exaceae as about 40 MYA. The Mozambique Channel land-bridge could have played an important role in the biogeographic history of the tribe Exaceae.

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“…A major component of this species turnover is replacement of individual species by closely related, ecologically similar species (Linder 1985;Linder et al 2006;Rebelo 2006;Richardson et al 2001). Many such groups of closely related, allopatric species are found in the region's most diverse lineages, including the Proteaceae, Restionaceae, and Ericaceae (Linder 2003(Linder , 2005Rebelo 2001).…”

Section: Introductionmentioning

confidence: 99%

Experimental biogeography: the role of environmental gradients in high geographic diversity in Cape Proteaceae

et al. 2009

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One of the fundamental dimensions of biodiversity is the rate of species turnover across geographic distance. The Cape Floristic Region of South Africa has exceptionally high geographic species turnover, much of which is associated with groups of closely related species with mostly or completely non-overlapping distributions. A basic unresolved question about biodiversity in this global hotspot is the relative importance of ecological gradients in generating and maintaining high geographic turnover in the region. We used reciprocal transplant experiments to test the extent to which abiotic environmental factors may limit the distributions of a group of closely related species in the genus Protea (Proteaceae), and thus elevate species turnover in this diverse, iconic family. We tested whether these species have a "home site advantage" in demographic rates (germination, growth, mortality), and also parameterized stage-structured demographic models for the species. Two of the three native species were predicted to have a demographic advantage at their home sites. The models also predicted, however, that species could maintain positive population growth rates at sites beyond their current distribution limits. Thus the experiment suggests that abiotic limitation under current environmental conditions does not fully explain the observed distribution limits or resulting biogeographic pattern. One potentially important mechanism is dispersal limitation, which is consistent with estimates based on genetic data and mechanistic dispersal models, though other mechanisms including competition may also play a role.

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Rapid and recent origin of species richness in the Cape flora of South Africa

Cited by 225 publications

References 13 publications

Island radiation on a continental scale: Exceptional rates of plant diversification after uplift of the Andes

Island radiation on a continental scale: Exceptional rates of plant diversification after uplift of the Andes

Monophyly and relationships of the tribe Exaceae (Gentianaceae) inferred from nuclear ribosomal and chloroplast DNA sequences

Experimental biogeography: the role of environmental gradients in high geographic diversity in Cape Proteaceae

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