title: Functional biogeography of oceanic islands and the scaling of functional diversity in the Azores.
abstract: Analyses of species-diversity patterns of remote islands have been crucial to the development of biogeographic theory, yet little is known about corresponding patterns in functional traits on islands and how, for example, they may be affected by the introduction of exotic species. We collated trait data for spiders and beetles and used a functional diversity index (FRic) to test for nonrandomness in the contribution of endemic, other native (also combined as indigenous), and exotic species to functional-trait space across the nine islands of the Azores. In general, for both taxa and for each distributional category, functional diversity increases with species richness, which, in turn scales with island area. Null simulations support the hypothesis that each distributional group contributes to functional diversity in proportion to their species richness. Exotic spiders have added novel trait space to a greater degree than have exotic beetles, likely indicating greater impact of the reduction of immigration filters and/or differential historical losses of indigenous species. Analyses of species occurring in native-forest remnants provide limited indications of the operation of habitat filtering of exotics for three islands, but only for beetles. Although the general linear (not saturating) pattern of trait-space increase with richness of exotics suggests an ongoing process of functional enrichment and accommodation, further work is urgently needed to determine how estimates of extinction debt of indigenous species should be adjusted in the light of these findings.
authors.affiliation: School of Geography and the Environment, University of Oxford, Oxford OX1 3QY, United Kingdom; Centre for Macroecology, Evolution and Climate, Department of Biology, University of Copenhagen, Copenhagen, Denmark; robert.whittaker@ouce.ox.ac.uk.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Whittaker
authors.affiliation: Azorean Biodiversity Group, Centro de Investigação e Tecnologias Agrárias dos Açores (CITA-A), and Platform for Enhancing Ecological Research and Sustainability (PEERS), Departamento de Ciências Agrárias, Universidade dos Açores, São Pedro, 9700-042 Angra do Heroísmo, Terceira, Azores, Portugal;
authors.forename: François
authors.initials: F
authors.lastname: Rigal
authors.affiliation: Azorean Biodiversity Group, Centro de Investigação e Tecnologias Agrárias dos Açores (CITA-A), and Platform for Enhancing Ecological Research and Sustainability (PEERS), Departamento de Ciências Agrárias, Universidade dos Açores, São Pedro, 9700-042 Angra do Heroísmo, Terceira, Azores, Portugal;
authors.forename: Paulo A V
authors.initials: PA
authors.lastname: Borges
authors.affiliation: Azorean Biodiversity Group, Centro de Investigação e Tecnologias Agrárias dos Açores (CITA-A), and Platform for Enhancing Ecological Research and Sustainability (PEERS), Departamento de Ciências Agrárias, Universidade dos Açores, São Pedro, 9700-042 Angra do Heroísmo, Terceira, Azores, Portugal; National Museum of Natural History, Smithsonian Institution, Washington, DC 20560; Finnish Museum of Natural History, University of Helsinki, 00014, Helsinki, Finland;
authors.forename: Pedro
authors.initials: P
authors.lastname: Cardoso
authors.affiliation: Azorean Biodiversity Group, Centro de Investigação e Tecnologias Agrárias dos Açores (CITA-A), and Platform for Enhancing Ecological Research and Sustainability (PEERS), Departamento de Ciências Agrárias, Universidade dos Açores, São Pedro, 9700-042 Angra do Heroísmo, Terceira, Azores, Portugal; Department of Ecology and Taxonomy, Faculty of Biology, National and Kapodistrian University of Athens, GR-15784 Athens, Greece;
authors.forename: Sofia
authors.initials: S
authors.lastname: Terzopoulou
authors.affiliation: Headquarters, Centro Agronómico Tropical de Investigación y Enseñanza, CATIE 7170, Cartago, Turrialba 30501, Costa Rica;
authors.forename: Fernando
authors.initials: F
authors.lastname: Casanoves
authors.affiliation: Complejo Docente el Hatillo, Universidad Nacional Experimental Francisco de Miranda, Apartado 7434, Coro 4101, Venezuela;
authors.forename: Laura
authors.initials: L
authors.lastname: Pla
authors.affiliation: Azorean Biodiversity Group, Centro de Investigação e Tecnologias Agrárias dos Açores (CITA-A), and Platform for Enhancing Ecological Research and Sustainability (PEERS), Departamento de Ciências Agrárias, Universidade dos Açores, São Pedro, 9700-042 Angra do Heroísmo, Terceira, Azores, Portugal; "Rui Nabeiro" Biodiversity Chair, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade de Évora, 7000-890 Évora, Portugal; and.
authors.forename: François
authors.initials: F
authors.lastname: Guilhaumon
authors.affiliation: School of Geography and the Environment, University of Oxford, Oxford OX1 3QY, United Kingdom; Institute of Biological Sciences and Health, Federal University of Alagoas, Maceió, Alagoas, Brazil.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Ladle
authors.affiliation: School of Geography and the Environment, University of Oxford, Oxford OX1 3QY, United Kingdom; Azorean Biodiversity Group, Centro de Investigação e Tecnologias Agrárias dos Açores (CITA-A), and Platform for Enhancing Ecological Research and Sustainability (PEERS), Departamento de Ciências Agrárias, Universidade dos Açores, São Pedro, 9700-042 Angra do Heroísmo, Terceira, Azores, Portugal; Department of Ecology and Taxonomy, Faculty of Biology, National and Kapodistrian University of Athens, GR-15784 Athens, Greece;
authors.forename: Kostas A
authors.initials: KA
authors.lastname: Triantis
mesh_terms: D000818:Animals; D001394:Azores; D044822:Biodiversity; D001517:Coleoptera / Q000502:physiology*; D058974:Phylogeography
keywords: arthropods; assembly rules; habitat destruction; island biogeography; saturation