Large-scale phylogenetic analyses reveal the causes of high tropical amphibian diversity

R. Alexander Pyron, John J. Wiens

Research output: Contribution to journalArticlepeer-review

207 Scopus citations


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 newphylogenetic 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.

Original languageEnglish (US)
Article number20131622
JournalProceedings of the Royal Society B: Biological Sciences
Issue number1770
StatePublished - Sep 11 2013


  • Amphibians
  • Diversification
  • Extinction
  • Latitudinal gradients
  • Speciation
  • Species richness

ASJC Scopus subject areas

  • General Immunology and Microbiology
  • General Biochemistry, Genetics and Molecular Biology
  • General Environmental Science
  • General Agricultural and Biological Sciences


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