Extinctions and threats to avifaunas on oceanic islands: Tests of influences of human populations and the filter effect
- Published
- Accepted
- Subject Areas
- Conservation Biology, Ecology, Statistics
- Keywords
- avifauna, filter effect, human population, mammalian predators, oceanic islands, path analysis
- Copyright
- © 2015 Zimbler-DeLorenzo et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ PrePrints) and either DOI or URL of the article must be cited.
- Cite this article
- 2015. Extinctions and threats to avifaunas on oceanic islands: Tests of influences of human populations and the filter effect. PeerJ PrePrints 3:e1528v1 https://doi.org/10.7287/peerj.preprints.1528v1
Abstract
Extinctions and threats of extinctions in avifaunas on oceanic islands appear to be influenced by several island characteristics and introduced mammalian predators. These predators may have caused a “filter effect”; low numbers of threatened avian species on some islands might be due to high rates of past extinctions. Using path analysis, we examined these factors and the influence of human population size (as an indicator of human activity) on the number of species extinctions and threatened bird species on islands. Human population size had substantial influences on the number of extinctions (standardized partial regression coefficient ρ = 0.315, N = 172, P = 0.0005) but not on the number of threatened species on oceanic islands (ρ = -0.061, P = 0.43), independent of the number of introductions of predator species. The number of extinctions on islands produced a significant filter effect (viz., had a negative impact; ρ = -0.186, P = 0.003) on the number of currently threatened species. The activities of human populations, including mammalian predators they introduced, have likely resulted in a greater number of bird extinctions on these islands, and producing a significant filter effect, wherein islands with larger human populations now have fewer threatened species.
Author Comment
This is a submission to PeerJ for review.