title: Large-scale phylogenetic analyses reveal the causes of high tropical amphibian diversity.
abstract: Many groups show higher species richness in tropical regions but the underlying causes remain unclear. Despite many competing hypotheses to explain latitudinal diversity gradients, only three processes can directly change species richness across regions: speciation, extinction and dispersal. These processes can be addressed most powerfully using large-scale phylogenetic approaches, but most previous studies have focused on small groups and recent time scales, or did not separate speciation and extinction rates. We investigate the origins of high tropical diversity in amphibians, applying new phylogenetic comparative methods to a tree of 2871 species. Our results show that high tropical diversity is explained by higher speciation in the tropics, higher extinction in temperate regions and limited dispersal out of the tropics compared with colonization of the tropics from temperate regions. These patterns are strongly associated with climate-related variables such as temperature, precipitation and ecosystem energy. Results from models of diversity dependence in speciation rate suggest that temperate clades may have lower carrying capacities and may be more saturated (closer to carrying capacity) than tropical clades. Furthermore, we estimate strikingly low tropical extinction rates over geological time scales, in stark contrast to the dramatic losses of diversity occurring in tropical regions presently.
authors.affiliation: Department of Biological Sciences, The George Washington University, , 2023 G Street NW, Washington, DC 20052, USA, Department of Ecology and Evolutionary Biology, University of Arizona, , Tucson, AZ 85721-0088, USA.
authors.forename: R Alexander
authors.initials: RA
authors.lastname: Pyron
authors.forename: John J
authors.initials: JJ
authors.lastname: Wiens
mesh_terms: D000663:Amphibians / Q000502:physiology*; D063147:Animal Distribution; D000818:Animals; D044822:Biodiversity; D053476:Extinction, Biological; D049810:Genetic Speciation; D005843:Geography; D010802:Phylogeny; D014329:Tropical Climate
keywords: amphibians; diversification; extinction; latitudinal gradients; speciation; species richness
references.citation: Evolution. 2006 Dec;60(12):2604-21
references.pmid: 17263120
references.citation: Science. 2004 Dec 3;306(5702):1783-6
references.pmid: 15486254
references.citation: Syst Biol. 2011 Jul;60(4):451-65
references.pmid: 21551125
references.citation: Am Nat. 2006 Nov;168(5):579-96
references.pmid: 17080358
references.citation: Ecol Lett. 2012 Nov;15(11):1318-1325
references.pmid: 22909289
references.citation: BMC Evol Biol. 2013 Feb 11;13:38
references.pmid: 23398853
references.citation: Proc Biol Sci. 2007 May 7;274(1614):1167-73
references.pmid: 17327208
references.citation: Proc Natl Acad Sci U S A. 2000 Aug 1;97(16):9115-20
references.pmid: 10922067
references.citation: Biol Rev Camb Philos Soc. 2005 Feb;80(1):1-25
references.pmid: 15727036
references.citation: Science. 2006 Oct 6;314(5796):102-6
references.pmid: 17023653
references.citation: Ecol Lett. 2011 Jul;14(7):643-52
references.pmid: 21535341
references.citation: Ecol Lett. 2008 Feb;11(2):173-83
references.pmid: 18070100
references.citation: Syst Biol. 2011 Jul;60(4):466-81
references.pmid: 21540408
references.citation: Am Nat. 2004 Mar;163(3):E1-23
references.pmid: 15026983
references.citation: Ecol Lett. 2010 Nov;13(11):1378-89
references.pmid: 20875038
references.citation: Syst Biol. 2007 Jun;56(3):369-88
references.pmid: 17520502
references.citation: Am Nat. 2007 Apr;169(4):E97-106
references.pmid: 17427118
references.citation: Evolution. 2009 May;63(5):1217-31
references.pmid: 19154386
references.citation: Science. 1987 Jan 9;235(4785):167-71
references.pmid: 17778629
references.citation: Evolution. 2009 Dec;63(12):3258-68
references.pmid: 19663993
references.citation: Evolution. 2010 Jun;64(6):1816-24
references.pmid: 20030708
references.citation: Am Nat. 2012 Oct;180(4):E75-89
references.pmid: 22976017
references.citation: Syst Biol. 2009 Dec;58(6):595-611
references.pmid: 20525612
references.citation: Q Rev Biol. 2011 Jun;86(2):75-96
references.pmid: 21800635
references.citation: Am Nat. 2004 Feb;163(2):192-211
references.pmid: 14970922
references.citation: Nature. 2012 Nov 15;491(7424):444-8
references.pmid: 23123857
references.citation: Ecol Lett. 2007 Apr;10(4):315-31
references.pmid: 17355570
references.citation: Science. 2013 Jan 4;339(6115):74-8
references.pmid: 23258408
references.citation: Nature. 2000 Dec 14;408(6814):847-50
references.pmid: 11130721
references.citation: Proc Biol Sci. 2010 Jul 22;277(1691):2131-8
references.pmid: 20335205
references.citation: Evolution. 2010 Feb 1;64(2):429-43
references.pmid: 19744118
references.citation: Mol Phylogenet Evol. 2011 Nov;61(2):543-83
references.pmid: 21723399
references.citation: Proc Natl Acad Sci U S A. 2007 Jan 16;104(3):887-92
references.pmid: 17213318
references.citation: Science. 2007 Mar 16;315(5818):1574-6
references.pmid: 17363673
references.citation: Ecol Lett. 2012 Aug;15(8):847-55
references.pmid: 22639858
references.citation: Proc Biol Sci. 2009 Mar 22;276(1659):993-4; discussion 995-7
references.pmid: 19129112
references.citation: PLoS Biol. 2012;10(3):e1001292
references.pmid: 22479151
references.citation: Syst Biol. 2010 Dec;59(6):619-33
references.pmid: 20884813
references.citation: Trends Ecol Evol. 2007 Nov;22(11):601-10
references.pmid: 17963995
references.citation: Ecol Lett. 2009 Aug;12(8):735-43
references.pmid: 19558515
references.citation: Ecol Lett. 2012 Mar;15(3):267-77
references.pmid: 22251895
references.citation: Evolution. 2013 Jun;67(6):1741-55
references.pmid: 23730766
references.citation: Proc Biol Sci. 2008 Oct 22;275(1649):2363-71
references.pmid: 18611849
references.citation: Proc Biol Sci. 2012 Apr 7;279(1732):1300-9
references.pmid: 21993508
references.citation: Ecology. 2006 Oct;87(10):2468-78
references.pmid: 17089656
references.citation: Proc Biol Sci. 2012 Jan 7;279(1726):194-201
references.pmid: 21632626
references.citation: Philos Trans R Soc Lond B Biol Sci. 1994 May 28;344(1309):305-11
references.pmid: 7938201
references.citation: Evolution. 2012 Jan;66(1):163-78
references.pmid: 22220872
references.citation: Am Nat. 2006 Dec;168(6):796-804
references.pmid: 17109321
references.citation: Proc Biol Sci. 2006 Sep 22;273(1599):2283-9
references.pmid: 16928629
references.citation: PLoS Biol. 2012 Aug;10(8):e1001381
references.pmid: 22969411
references.citation: Evolution. 2008 Nov;62(11):2775-88
references.pmid: 18752598
references.citation: Trends Ecol Evol. 2004 Dec;19(12):639-44
references.pmid: 16701326
references.citation: Am Nat. 2007 Aug;170 Suppl 2:S86-106
references.pmid: 17874387
references.citation: Proc Natl Acad Sci U S A. 2006 May 16;103(20):7718-22
references.pmid: 16672371