A global model of island species–area relationships

Research output: Contribution to journalArticle


  • Tom Matthews
  • François Rigal
  • Kostas A. Triantis
  • Robert J. Whittaker

Colleges, School and Institutes


The increase in species richness with island area (ISAR) is a well-established global pattern, commonly described by the power model, the parameters of which are hypothesized to vary with system isolation and to be indicative of ecological process regimes. We tested a structural equation model of ISAR parameter variation as a function of taxon, isolation, and archipelago configuration, using a globally distributed dataset of 151 ISARs encompassing a range of taxa and archipelago types. The resulting models revealed a negative relationship between ISAR intercept and slope as a function of archipelago species richness, in turn shaped by taxon differences and by the amount and disposition of archipelago area. These results suggest that local-scale (intra-archipelago) processes have a substantial role in determining ISAR form, obscuring the diversity patterns predicted by island theory as a function of archipelago isolation. These findings have implications for the use and interpretation of ISARs as a tool within biogeography, ecology, and conservation.


Original languageEnglish
Pages (from-to)12337–12342
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number25
Early online date30 May 2019
Publication statusPublished - 18 Jun 2019


  • archipelago effects, diversity model, island biogeography, macroecology, species-area relationship