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Preserving the evolutionary potential of floras in biodiversity hotspots


One of the biggest challenges for conservation biology is to provide conservation planners with ways to prioritize effort. Much attention has been focused on biodiversity hotspots1. However, the conservation of evolutionary process is now also acknowledged as a priority in the face of global change2. Phylogenetic diversity (PD) is a biodiversity index that measures the length of evolutionary pathways that connect a given set of taxa3,4. PD therefore identifies sets of taxa that maximize the accumulation of ‘feature diversity’. Recent studies, however, concluded that taxon richness is a good surrogate for PD5,6,7,8,9. Here we show taxon richness to be decoupled from PD, using a biome-wide phylogenetic analysis of the flora of an undisputed biodiversity hotspot—the Cape of South Africa. We demonstrate that this decoupling has real-world importance for conservation planning. Finally, using a database of medicinal and economic plant use10, we demonstrate that PD protection is the best strategy for preserving feature diversity in the Cape. We should be able to use PD to identify those key regions that maximize future options, both for the continuing evolution of life on Earth and for the benefit of society.

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Figure 1: Taxon richness and phylogenetic diversity in the Cape.
Figure 2: Complementarity analysis of PD and genus richness.


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We thank E. Arnold, K. Balele, W. Barrington, N. Bergh, F. Conrad, L. Csiba, C. Cupido, A. Dold, the Fourcade Botanical Club, K. Davis, J. Donaldson, P. Drew, T. Fulcher, G. Gardiner, J. Gittleman, P. Goldblatt, N. Helme, E. Kapinos, A. Khunou, N. B. Lester, A. Mabunda, M. Powell, D. Snijman, K. Tolley, T. Trinder-Smith, A. G. Verboom, E. van Jaarsveld, S. Vetter, C. Williams, M. Wolfson, F. Woodvine, and especially I. Nänni, for assistance; the conservation authorities of the Western, Eastern and Northern Cape in South Africa for granting collecting permits as well as the managers of nature reserves and private landowners; A. Proust/iAfrika for the picture in Fig. 1; and T. Barraclough, M. Chase and H. Possingham for comments on the manuscript. We thank the Darwin Initiative for the Survival of Species, the South African National Biodiversity Institute, the University of Cape Town, the Royal Botanic Gardens Kew, the Bentham-Moxon Trust, the US National Science Foundation, the University of Virginia and the European Commission (HOTSPOTS/EDIT) for funding.

DNA sequences have been deposited at GenBank/EMBL under accession numbers AM234779–AM235167 (see also Supplementary Information)

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Correspondence to Félix Forest or Vincent Savolainen.

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Competing interests

DNA sequences have been deposited at GenBank/EMBL under accession numbers AM234779–AM235167 (see also Supplementary Information). Reprints and permissions information is available at The authors declare no competing financial interests.

Supplementary information

Supplementary Information

This file contains Supplementary Methods, Supplementary Table 1 and Supplementary Figures 1-6. (PDF 1380 kb)

Supplementary Table

This file contains a table listing the taxa included in the phylogenetic analysis of Cape angiosperm genera based on rbcL plastid sequences and associated Genbank/EMBL accession numbers. Genera with one Cape species recorded in the SEPASAL database ( are indicated. (PDF 694 kb)

Supplementary Information

This file contains the phylogenetic tree of the Cape flora (chronogram) and the optimization of the three types of utility. (PDF 564 kb)

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Forest, F., Grenyer, R., Rouget, M. et al. Preserving the evolutionary potential of floras in biodiversity hotspots. Nature 445, 757–760 (2007).

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