Invasive Alien Species represent the greatest threat to seabirds globally (Croxall et al. 2012), causing adult mortality and reduced productivity owing to egg and chick predation. Little data exists on the presence of invasive alien species at Bikar Atoll. The atoll is uninhabited by humans, although it is visited by the Marshallese and evidence of a previous ship wreck was noted in 1964 (Amerson, 1967). Polynesian Rat does occur and there are unconfirmed reports of the introduction of another rat species in recent years. Polynesian Rat is ubiquitous throughout the Pacific (IUCN SSC Invasive Species Specialist Group 2012) and has been recorded predating adult seabirds as well as eggs and chicks (Kepler 1967). Black Rat, Feral Cat, Feral Pig and Feral Goat are all plausible but unconfirmed residents. Each can potentially cause declines in seabird colonies, and ungulates can exacerbate the threat from other invasive mammals through habitat modification (Atkinson 1985, Rodríguez et al. 2006, Jones et al. 2008, Duffy 2010). Overall, invasive mammals are suspected to be present and are likely to be having a limiting effect on seabirds, or causing population declines.
Climate change is listed as the third greatest threat to seabirds globally (Croxall et al. 2012). It is predicted to decrease the land area of low-lying Pacific islands and cause complete inundation of some islands (IPCC 1997) leading to substantial population declines (Hatfield et al. 2012). Although no current data or predictions are available specific to this IBA climate change represents a potential threat to this site owing to the risk of future sea level rise leading to inundation, and increased frequency of storms.
BirdLife International (2022) Important Bird Areas factsheet: Moruroa. Downloaded from
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