National Park of American Samoa - Tutuila (31293)
American Samoa, Oceania
Site overview
KBA status: confirmed
Year of last assessment: 2012
National site name: National Park of American Samoa - Tutuila
Central coordinates: Latitude: -14.2583, Longitude: -170.6832
System: marine, terrestrial
Elevation (m): 0 to 490
Area of KBA (km2): 11.49926
Protected area coverage (%): 84.47
KBA classification: Global/Regional TBD
Legacy site: Yes
Site details
Rationale for qualifying as KBA: This site qualifies as a Key Biodiversity Area of international significance because it meets one or more previously established criteria and thresholds for identifying sites of biodiversity importance (including Important Bird and Biodiversity Areas, Alliance for Zero Extinction sites, and Key Biodiversity Areas)
Threats
Summary of threats to biodiversity at KBA: 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). Hurricanes have been documented to cause severe population changes in the forest bird species on American Samoa, with some species seeing population decreases of more than 50% four months after a hurricane (Trail et al. 1992). Although no data for seabirds or long term predictions are available specific to this IBA climate change represents a potential threat to this site owing to the risk of future increased frequency of storms. 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. Polynesian Rat is ubiquitous throughout the Pacific (IUCN SSC Invasive Species Specialist Group 2012) and is confirmed to be present along with brown rats and black rats (SPREP, 2000). Rats have been recorded predating adult seabirds as well as eggs and chicks (Kepler 1967). They have precipitated island extinctions in small-bodied, ground-nesting seabirds, but their impacts on larger or arboreal nesting seabirds appear to be lower (Atkinson 1985, Jones et al. 2008). 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 know to be present and are likely to be having a limiting effect on seabirds, or causing population declines. Human disturbance and direct harvesting of seabirds are listed as threats to 26 and 23 of the 97 globally threatened seabirds respectively (Croxall et al. 2012). For Near Threatened and Least Concern species it is likely that human disturbance and consumption affect an even greater proportion, particularly of tropical species, for which major reductions in populations and/or breeding sites are increasingly indicated but seldom quantified, especially across the whole range of the many wide-ranging tropical seabird species (Croxall et al. 2012). Direct harvesting of forest bird species does occur at this site and is known to impact on populations after hurricane impacts (Trail et al. 1992). It is unknown if this direct harvesting affects the seabird populations. The sustainability of such harvests is unknown but it may represent a threat to this population. Seabirds are highly visually oriented and known to become disorientated at night in the presence of artificial light (Bruderer et al., 1999). On archipelagos worldwide, thousands of fledglings of different petrel species are attracted to artificial lights during their first flights from nest-burrows to the sea, a phenomenon called ‘fallout’ (Reed et al. 1985, Telfer et al. 1987, Le Corre et al. 2002, Rodríguez & Rodríguez 2009, Miles et al. 2010, Rodrigues et al. 2011). Grounded birds are vulnerable to starvation, predation, dehydration and collision with vehicles. The prevalence of this potential threat at this site is not known but it may be having a negative impact.
Additional information
References: Atkinson, I. A. E. (1985) The spread of commensal species of Rattus to oceanic islands and their effect on island avifaunas. Pages 35-81 in P. J. Moors, editor. Conservation of island birds. International Council for Bird Preservation, Cambridge, United Kingdom. Bruderer, B., Peter, D. and Steuri, T. (1999) Behavior of migrating birds exposed to Xband radar and a bright light beam. Journal of Experimental Biology 202: 1015–1022. Le Corre, M., Ollivier, A., Ribes, S. and Jouventin, P. (2002) Light-induced mortality of petrels: a 4-year study from Réunion Island (Indian Ocean). Biol. Conserv. 105: 93–102. Croxall, J. P., Butchart, S. H. M., Lascelles, B., Stattersfield, A. J., Sullivan, B., Symes, A. and Taylor, P. (2012) Seabird conservation status, threats and priority actions: a global assessment. Bird Conservation International 22: 1-34. Duffy, D. C. (2010) Changing Seabird Management in Hawai‘i: from exploitation through management to restoration. Waterbirds 33: 193-207. Hatfield, J. S., Reynolds, M. H., Seavy, N. E. and Krause, C. M. (2012) Population dynamics of Hawaiian seabird colonies vulnerable to sea-level rise. Conservation Biology 26: 667-678. IPCC – Intergovernmental Panel On Climate Change (1997) The Regional Impacts of Climate Change. An Assessment of Vulnerability. Geneva. IUCN SSC Invasive Species Specialist Group (2012) Rattus exulans. Global Invasive Species Database. Downloaded from http://www.issg.org/database/species/ecology.asp?si=170&fr=1&sts=sss on 8th October 2012. Jones, H. P., Tershy, B. R., Zavaleta, E. S., Croll, D. A., Keitt, B. S., Finkelstein, M. E. and Howald, G. R. (2008) Severity of the effects of invasive rats on seabirds: a global review. Conservation Biology 22: 16-26. Kepler, B. (1967) Polynesian rat predation on nesting Laysan Albatrosses and other Pacific seabirds. Auk 84: 426-430. Miles, W., Money, S., Luxmoore, R. and Furness, R.W. (2010) Effects of artificial lights and moonlight on petrels at St Kilda. Bird Study 57: 244–251. Reed, J.R., Sincock, J.L. & Hailman, J.P. (1985) Light attraction in endangered Procellariiform birds: reduction by shielding upward radiation. Auk 102: 377–383. Rodrigues, P., Aubrecht, C., Gil, A., Longcore, T. and Elvidge, C. (2011) Remote sensing to map influence of light pollution on Cory’s Shearwater in São Miguel Island, Azores Archipelago. Eur. J. Wildl. Res. doi: 10.1007/s10344-011-0555-5. Rodríguez, A. and Rodríguez, B. (2009) Attraction of petrels to artificial lights in the Canary Islands: effect of the moon phase and age class. Ibis 151: 299–310. Rodríguez, C., Torres, R. and Drummond, H. (2006) Eradicating introduced mammals from a forested tropical island. Biological Conservation 130: 98-105. Telfer, T.C., Sincock, J.L., Byrd, G.V. and Reed, J.R. (1987) Attraction of Hawaiian seabirds to lights: conservation efforts and effects of moon phase. Wildl. Soc. Bull. 15: 406–413. Trail, P., Morrell, A. and Tualauleleli, A. (1992) Declines in land bird populations on Tutuila, American Samoa, 1986-1992. Department of Marine and Wildlife Resources Biological Report Series, No. 32.