Vatu-i-Ra (20328)
Fiji, Oceania
Site overview
KBA status: confirmed
Global KBA criteria: B1, D1a
Year of last assessment: 2006
National site name: Vatu-i-Ra
Central coordinates: Latitude: -17.3667, Longitude: 178.4333
System: marine, terrestrial
Elevation (m): 0 to 65
Area of KBA (km2): 0.0233
Protected area coverage (%): 90.35
KBA classification: Global
Legacy site: Yes
Site details
Site description: Vatu-i-Ra is a small island approximately 100m by 300m wide, comprising two small hills connected by a narrow neck. The higher north-east side and each end of the island are composed of volcanic rock. The rest of the islands consists of flat coral sand, not far above spring high tide level.
Rationale for qualifying as KBA: This site qualifies as a Key Biodiversity Area of international significance that meets the thresholds for at least one criterion described in the Global Standard for the Identification of KBAs.
Additional biodiversity: Vatu-i-Ra is one of the most regularly monitored sites in Fiji with data available from over 15 survey visits extending back to 1963. The island qualifies as an IBA owing to its internationally significant population of Black Noddy. It can be difficult to compare between survey years as different methods have been used to count seabird populations. Counts of apparently occupied nests were lower in 1963 (1500 estimated by Morris) and 1974 (4550 - Tarburton 1978) than in recent years with total nest counts of c.26,000 in 2003 (BirdLife International 2003), c.29,000 in 2008 (Roneil et al. 2008) and c.21,000 in 2011 (BirdLife International, unpublished data). However, estimates of the number of adults during regular visits between 1974 and 1981 based on mark-recapture extrapolations from a banded sample of birds fluctuate between 10,865 and 58,203 (Tarburton 1987). These estimates are roughly comparable with total population estimates we can derive from the number of apparently occupied nests between 2003 and 2011 (based on a ratio of 1 nest: 3 adults including non-breeding birds). Elsewhere, Black Noddy populations show considerable within-season, inter-annual and decadal population fluctuations (Congdon et al. 2007), so it is not yet possible to detect long-term population trends, or to definitively say whether the removal of rats from the island is allowing a population increase. As a tree-nesting species Black Noddy is not highly susceptible to egg-predation by rats. While Black Noddies from Vatu-i-Ra have been shown to disperse as far as the Solomon Islands during the non-breeding season (Tarburton 1987), the species is predominantly sedentary, often roosting within breeding colonies during the non-breeding season, and it is considered a principally near-shore species (BirdLife International Foraging Range Database). The site also supports key populations of a number of other seabird species. Estimates of the number of breeding seabirds have remained relatively constant with: Red-footed Booby - 300–500 nests in 1963 (Morris undated), 400 nests in 1974 (Tarburton 1978), 400 individuals in 2003 (BirdLife International 2003), 600 individuals in 2006 (Environment Consultants 2006), 500 individuals in 2007 (Nature Fiji-Mareqeti Viti 2007) and 500 individuals in 2010 (Rosenstein 2010); Lesser Frigatebird - 500–700 pairs in 1963, 250 pairs in 1974, 150–250 non-breeders in 2003, >500 in 2008 (Morris undated; Tarburton 1978; Roneil et al. 2008); Brown Noddy - 80 pairs in 1970s, 50–100 pairs in 2003 (Tarburton 1986; BirdLife International 2003); White-tailed Tropicbird - one pair in 1974, one bird seen in 2003 (Tarburton 1978; BirdLife International 2003); and Black-naped Tern - 20-115 birds recorded over the period. No firm conclusions can be drawn yet, but there is some evidence of increased nesting in recent years of some ground-nesting species, those most likely to suffer egg-predation by rats. These include Bridled Tern - 14 pairs in 1974, 200 pairs in 2003 and >500 adults in 2011 (Tarburton 1986; BirdLife International 2003; BirdLife International unpublished data, 2011); Brown Booby - no historic breeding recorded but small numbers of nests from 2006 onwards and up to 150 adults counted after 2006 (Environment Consultants 2006; Nature Fiji-Mareqeti Viti 2007); and Crested Tern - recorded in very low numbers historically before counts increased post 2003 to 120 in 2008 and with the first breeding record of 250 pairs in 2011 (Roneil et al. 2008; Bird 2011). Other species breeding on Vatu-i-Ra is the Eastern Reef Heron (1 pair in 1974; 2 birds in 2003) and possibly Polynesian Starling (BirdLife International unpublished data); and some migrants visit including shorebirds and Barn Owl. Non-bird biodiversity: Turtles have been reported to nest on the beach. An endemic skink, Pygmy Snake-eyed Skink, also occurs on Vatu-i-Ra.
Other site values: The island is uninhabited but is regularly visited by fishers and occasional tourists on dive trips. The island is under the Native Tenure and is owned by the Nagilogilo clan.
Habitats
Summary of habitats in KBA: Most of the islands is covered by vegetation, with taller Pisonia trees in the centre and on the outside shorter shrub-like trees (possibly Hibiscus tiliaceus). Several exposed areas, including one slope of the main hill at the southern end of the island become covered with couch-grass after sufficient rain (Tarburton 1978).
Land use: fisheries/aquaculture | nature conservation and research | not utilised | tourism/recreation
| IUCN Habitat | Coverage % | Habitat detail |
|---|---|---|
| Marine Neritic | 45 | |
| Marine Intertidal | 5 | |
| Marine Coastal/Supratidal | 5 | |
| Forest | 45 |
Threats
Summary of threats to biodiversity at KBA: The major threat to the island's avifauna is the introduction of alien invasive species to the site. Human disturbance by fishers and tourists on diving trips could disrupt seabird breeding, particularly of ground-nesting species. Opportunistic harvest of chicks and eggs for food represents a potential threat.
| Threat level 1 | Threat level 2 | Threat level 3 | Timing |
|---|---|---|---|
| Invasive & other problematic species, genes & diseases | Invasive non-native/alien species/diseases | Unspecified species | Only in the past and unlikely to return |
| Human intrusions & disturbance | Recreational activities | Ongoing | |
| Human intrusions & disturbance | Work & other activities | Ongoing | |
| Climate change & severe weather | Storms & flooding | Only in the future |
Additional information
References: Barrit, W.K.(1979/1980) Seabird observations in Fijian waters. Sea Swallow 30:22-36. Bird, J. P. et al. (in prep.) The identification of marine Important Bird Areas in the western South Pacific. Bird, J. (2011) eBird: An online database of bird distribution and abundance [web application]. Version 2. eBird, Ithaca, New York. Available: http://www.ebird.org. (Accessed: January 1, 2012). BirdLife International (2003) Field Report No. 19: Bird Survey of Vatu-i-Ra Island, 18-19 and 22-23 December 2003. BirdLife International, Suva, Fiji. Congdon, B. C., Erwin, C. A., Peck, D. R., Baker, G. B., Double, M. C. and O’Neill, P. (2007) Vulnerability of seabirds on the Great Barrier Reef to climate change. In: Climate Change and the Great Barrier Reef: a vulnerability assessment. Great Barrier Reef Marine Park Authority and Australian Greenhouse Office, Townsville, QLD, Australia, pp. 465-497. Environment Consultants (2006) First Monitoring Survey of Vatuira Island, Lomaiviti, Fiji - August 15-20, 2006. Unpublished report to BirdLife International. Morris, R. O. (Undated) Unpublished notes on birds observed in Fiji. NatureFiji-MareqetiViti (2007) Second Monitoring Survey of Vatuira Island, Lomaiviti, Fiji - June 8-11, 2007. Unpublished report to BirdLife International. Roneil, J., Seniloli, E., Cranwell, S. and Tuamoto, T. (2008) Third Monitoring Survey of Vatu-i-Ra Island, Lomaiviti, Fiji - January 14-17, 2008. Unpublished report to BirdLife International. Rosenstein, M. (2010) eBird: An online database of bird distribution and abundance [web application]. Version 2. eBird, Ithaca, New York. Available: http://www.ebird.org. (Accessed: February 2, 2011). Tarburton, M.K.(1978) Some recent observations on seabirds breeding in Fiji. Notornis 25: 303-316. Tarburton M.K.(1987) Migration and breeding strategy of the Black Noddy, Fiji. Emu 87: 50-52.