title: Bird assemblage vulnerability depends on the diversity and biogeographic histories of islands.
abstract: Biodiversity is widely acknowledged to influence the magnitude and stability of a large array of ecosystem properties, with biodiverse systems thought to be more functionally robust. As such, diverse systems may be safer harbors for vulnerable species, resulting in a positive association between biodiversity and the collective vulnerability of species in an assemblage, or "assemblage vulnerability." We find that, for 35 islands across Northern Melanesia, bird assemblage vulnerability and biodiversity are positively associated. This relationship is highly contingent on Pleistocene connectivity, suggesting that biogeographic history-a factor often overlooked in biodiversity and ecosystem-functioning studies-may influence contemporary ecological processes. In the face of biodiversity loss attributable to anthropogenic drivers, reduced ecosystem functioning may erode the safe harbors of vulnerable assemblages. Paradoxically, these results suggest that biodiverse systems, as more robust systems, may experience greater biodiversity loss over ecological time because they harbor more vulnerable species accumulated over evolutionary time.
authors.affiliation: Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, NY 10027; Department of Ornithology, American Museum of Natural History, New York, NY 10024; bcw2115@columbia.edu.
authors.forename: Brian C
authors.initials: BC
authors.lastname: Weeks
authors.affiliation: Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, NY 10027; Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom;
authors.forename: Nichar
authors.initials: N
authors.lastname: Gregory
authors.affiliation: Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, NY 10027; Earth Institute Center for Environmental Studies, Columbia University, New York, NY 10027.
authors.forename: Shahid
authors.initials: S
authors.lastname: Naeem
mesh_terms: D000818:Animals; D044822:Biodiversity; D005075:Biological Evolution; D001717:Birds / Q000502:physiology*; D003247:Conservation of Natural Resources; D017753:Ecosystem; D062312:Islands; D008542:Melanesia; D058974:Phylogeography; D011157:Population Dynamics / Q000639:trends
keywords: biodiversity; ecosystem functioning; extinction risk; historical biogeography; species loss