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Biological invasions on oceanic islands: Implications for island ecosystems and avifauna

Pearson, Dean E. 2009. Biological invasions on oceanic islands: Implications for island ecosystems and avifauna. In: Chae, H.Y.; Choi, C.Y.; Nam, H.Y., eds. Seabirds in danger: Invasive species and conservation of island ecosystem; proceeding, 3rd international symposium on migratory birds; 25 September 2009; Mokpo, Korea. Shinan, Korea: National Park Migratory Birds Center. p. 3-16.

Biological invasions present a global threat to biodiversity, but oceanic islands are the systems hardest hit by invasions. Islands are generally depauperate in species richness, trophic complexity, and functional diversity relative to comparable mainland ecosystems. This situation results in low biotic resistance to invasion and many empty niches for invaders to exploit. It also results in island species being poorly adapted for dealing with predators, herbivores, and strong competitors. Hence, invaders tend to be more successful on oceanic islands and their impacts tend to be much stronger, often resulting in species extinctions and restructuring of communities and ecosystem functions. Birds play particularly important ecological roles on oceanic islands, where they are generally the most diverse terrestrial vertebrate group due to the general absence of mammals and low diversity of reptiles and amphibians. As a result, birds can completely dominate or contribute very strongly to various key functional roles such as herbivory, pollination, seed dispersal, predation, ecosystem engineering, and nutrient transport. For similar reasons, island birds are very susceptible to invader impacts and are important system-level transmitters of invader impacts. Invasive species management on islands is challenging, but some of the same factors that render islands particularly sensitive to biological invasions also favor successful invasive species management. The small size and isolation of many islands ensures relatively small invader populations and discrete management areas that facilitate extirpation of the invader and its exclusion following eradication. In recent decades, island invasives management has focused on extirpation of exotic species and hundreds of islands have been cleared of exotic predators, herbivores, and sometimes plants. In most situations, invader extirpation has helped to restore the system, but in numerous cases restoration has failed due to complex side effects. Taking a broader community-level approach to invasive species management on islands will help improve success and reduce unexpected deleterious side effects.

Keywords: biological invasions, oceanic islands, birds, invasive species

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Title: RMRS Other Publications: Biological invasions on oceanic islands: Implications for island ecosystems and avifauna
Electronic Publish Date: April 4, 2012
Last Update:
April 4, 2012

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