Equilibrium and non-equilibrium dynamics simultaneously operate in the Galápagos islands

Luis M. Valente*, Albert B. Phillimore, Rampal S. Etienne

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

37 Citations (Scopus)
229 Downloads (Pure)

Abstract

Island biotas emerge from the interplay between colonisation, speciation and extinction and are often the scene of spectacular adaptive radiations. A common assumption is that insular diversity is at a dynamic equilibrium, but for remote islands, such as Hawaii or Galapagos, this idea remains untested. Here, we reconstruct the temporal accumulation of terrestrial bird species of the Galapagos using a novel phylogenetic method that estimates rates of biota assembly for an entire community. We show that species richness on the archipelago is in an ascending phase and does not tend towards equilibrium. The majority of the avifauna diversifies at a slow rate, without detectable ecological limits. However, Darwin's finches form an exception: they rapidly reach a carrying capacity and subsequently follow a coalescent-like diversification process. Together, these results suggest that avian diversity of remote islands is rising, and challenge the mutual exclusivity of the non-equilibrium and equilibrium ecological paradigms.

Original languageEnglish
Pages (from-to)844-852
Number of pages9
JournalEcology Letters
Volume18
Issue number8
DOIs
Publication statusPublished - Aug-2015

Keywords

  • Community assembly
  • diversification
  • dynamic equilibrium
  • island biogeography
  • phylogeny
  • ADAPTIVE RADIATION
  • DARWINS FINCHES
  • GENE FLOW
  • PHYLOGENETIC-RELATIONSHIPS
  • MOLECULAR PHYLOGENIES
  • DIVERSITY-DEPENDENCE
  • DIVERSIFICATION
  • EVOLUTION
  • SPECIATION
  • MODEL

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