Access

Letters to Nature

Nature 412, 181-183 (12 July 2001) | doi:10.1038/35084067; Received 17 January 2001; Accepted 29 May 2001

Open Innovation Challenges

naturejobs

More science jobs
Post a job for free

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

James E. Richardson1,2, Frans M. Weitz3,4, Michael F. Fay1, Quentin C. B. Cronk5,6, H. Peter Linder2,4, G. Reeves1 & Mark W. Chase1

  1. Jodrell Laboratory, Royal Botanic Gardens, Richmond, Surrey TW9 3DS, UK
  2. Department of Botany, University of Western Cape, Bellville 7535, Cape Province, South Africa
  3. Bolus Herbarium, Botany Department, University of Cape Town, Rondebosch 7700, South Africa
  4. Institute of Cell and Molecular Biology, University of Edinburgh, Darwin Building, King's Buildings, Mayfield Road, Edinburgh EH9 3JR, UK
  5. Royal Botanic Garden, 20A Inverleith Row, Edinburgh EH3 5LR, UK
  6. Present address: Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, California 95064, USA (J.E.R.); Institute for Systematic Botany, Zollikerstrasse 107, CH8008, Zurich, Switzerland (H.P.L.); Kirstenbosch Research Centre, National Botanical Institute, Rhodes Drive, Newlands 7735, Cape Town, South Africa (G.R.).

Correspondence to: James E. Richardson1,2 Correspondence and requests for material should be addressed to J.E.R. (e-mail: Email: jamesr@darwin.ucsc.edu).

Top

The Cape flora of South Africa grows in a continental area with many diverse and endemic species1, 2, 3, 4. We need to understand the evolutionary origins and ages of such 'hotspots' to conserve them effectively5. In volcanic islands the timing of diversification can be precisely measured with potassium–argon dating. In contrast, the history of these continental species is based upon an incomplete fossil record and relatively imprecise isotopic palaeotemperature signatures. Here we use molecular phylogenetics and precise dating of two island species within the same clade as the continental taxa to show recent speciation in a species-rich genus characteristic of the Cape flora. The results indicate that diversification began approximately 7–8 Myr ago, coincident with extensive aridification caused by changes in ocean currents. The recent origin of endemic species diversity in the Cape flora shows that large continental bursts of speciation can occur rapidly over timescales comparable to those previously associated with oceanic island radiations6, 7.