title: Evolution of a hotspot genus: geographic variation in speciation and extinction rates in Banksia (Proteaceae).
abstract: BACKGROUND
  Hotspots of angiosperm species richness and endemism in Mediterranean-climate regions are among the most striking, but least well-understood, geographic patterns of biodiversity. Recent studies have emphasized the importance of rapid diversification within hotspots, compared to non-hotspot regions, as a major contributor to these patterns. We constructed the first near-complete phylogeny of Banksia (Proteaceae) to test whether diversification rates have differed between lineages confined to the southwest Australian hotspot and those found throughout southern, eastern and northern Australia. We then tested for variation in diversification rates among the bioclimatic zones within the southwest hotspot itself.
  
  
  RESULTS
  Although Banksia species richness in the southwest is ten times that of the rest of the continent, we find little evidence for more rapid diversification in the southwest, although this result is inconclusive. However, we find firmer support for substantial rate variation within the southwest hotspot, with more rapid diversification in the semi-arid heaths and shrublands, compared to the high-rainfall forests. Most of the Banksia diversity of the southwest appears to be generated in the heaths and shrublands, with a high migration rate out of this zone boosting diversity of the adjacent forest zone.
  
  
  CONCLUSIONS
  The geographic pattern of diversification in Banksia appears more complex than can be characterized by a simple hotspot vs. non-hotspot comparison, but in general, these findings contrast with the view that the high diversity of Mediterranean hotspots is underpinned by rapid radiations. Steady accumulation of species at unexceptional rates, but over long periods of time, may also have contributed substantially to the great botanical richness of these regions.
authors: Macroevolution and Macroecology Group, Research School of Biology, Australian National University, Canberra, ACT 0200, Australia. marcel.cardillo@anu.edu.au
authors: Marcel
authors: M
authors: Cardillo
authors: Renae
authors: R
authors: Pratt
mesh_terms: D001315:Australia; D044822:Biodiversity; D002980:Climate; D019143:Evolution, Molecular; D049810:Genetic Speciation; D014644:Genetic Variation; D005843:Geography; D010802:Phylogeny; D039105:Proteaceae / Q000145:classification / Q000235:genetics*
references: Mol Phylogenet Evol. 2009 Apr;51(1):1-4
references: 19269338
references: PLoS One. 2012;7(11):e50974
references: 23209839
references: Proc Biol Sci. 2000 Nov 22;267(1459):2267-72
references: 11413642
references: Syst Biol. 2011 Jul;60(4):451-65
references: 21551125
references: BMC Evol Biol. 2007 Nov 08;7:214
references: 17996036
references: Science. 2005 Sep 9;309(5741):1722-5
references: 16151011
references: Bioinformatics. 2011 Feb 15;27(4):592-3
references: 21169378
references: Mol Phylogenet Evol. 2007 Jun;43(3):1106-17
references: 17434758
references: Trends Ecol Evol. 1996 Sep;11(9):362-6
references: 21237880
references: Mol Phylogenet Evol. 2009 Apr;51(1):44-53
references: 18411064
references: Syst Biol. 2009 Jun;58(3):367-80
references: 20525591
references: Mol Ecol Resour. 2012 Mar;12(2):299-311
references: 22085307
references: Evolution. 2010 Mar 1;64(3):745-60
references: 19804404
references: Proc Natl Acad Sci U S A. 2009 Jan 6;106(1):221-5
references: 19116275
references: BMC Evol Biol. 2013 Feb 11;13:38
references: 23398853
references: Philos Trans R Soc Lond B Biol Sci. 2008 Sep 27;363(1506):3097-105
references: 18579472
references: Syst Biol. 2007 Oct;56(5):701-10
references: 17849325
references: Biol Rev Camb Philos Soc. 2003 Nov;78(4):597-638
references: 14700393