Tofua and Kao (24507)
Tonga, Oceania
Site overview
KBA status: confirmed
Global KBA criteria: B2
Year of last assessment: 2007
National site name: Tofua and Kao
Central coordinates: Latitude: -19.7501, Longitude: -175.0720
System: marine, terrestrial
Elevation (m): 0 to 558
Area of KBA (km2): 67.4449
Protected area coverage (%): 96.91
KBA classification: Global
Legacy site: Yes
Site details
Site description: The Tofua IBA comprises the whole island of Tofua, a 46.6 sq. km active volcanic island which retains the largest area of biodiversity rich moist tropical forest in Tonga. The island has seven of the ten central Polynesian restricted range species, and is particularly important for the Tongan populations of the Fiji shrikebill Clytorhynchus vitiensis and the blue-crowned lorikeet Vini australis. The island is inhabited and the on-going clearing of forest for kava plantations is a significant conservation concern as is the presence of feral pigs. Very little is documented on the avifauna and biodiversity of Tofua, for instance there are no seabird records from the island.
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. KBA identified in the CEPF Ecosystem Profile of the Polynesia-Micronesia Hotspot (2007). Taxonomy, nomenclature and threat status follow the 2003 IUCN Red List.
Additional biodiversity: Ornithological information The volcanic islands of Tofua (55.4 km2) and Late (17 km2) are recognised as having some of Tonga’s best remaining high diversity native forest and still support large populations of birds and reptiles (Steadman 1998) with Tofua’s forest complement being nearly three times the area of that of Late. However, Tofua’s birds and biodiversity in general is very poorly documented and there are no seabird records from the island. Confirmed records from the island still rely greatly on the Whitney South Seas Expedition which collected on 27-28 July 1925. Dieter Rinke and colleagues visited the island briefly in October 1990 with a single observation documented (Rinke et al 1992). Steadman (2006) records observations made in July 1995 and July 1996 which confirmed one additional species. These are summarised in the table below. Of particular significance is the suite of seven ‘central polynesian’ restricted range species (A2). Non-bird biodiversity: No records.
Delineation rationale: 2012-12-17 (BL Secretariat): original polygon clipped to hi-res coastline following identification in October 2012 of new marine IBA offshore this site; site area consequently changed from 4660 ha to 5506 ha. 2015-10-20 (BL Secretariat): IBA includes the KBA 'Kao and Tofua National Parks' (CEPF Ecosystem Profile 2007).
Habitats
Summary of habitats in KBA: Tofua is an almost circular island eight kilometres across at its widest point. The island contains a five kilometres caldera with a steep sided rim rising to 558 m. Inside, 23 m above sea level is the brackish lake, Lofia, which is 3 km wide. The volcano is still active – inside the northern edge of the caldera three young cones have built up. Lava sometimes pours out from one vent, and smoke, steam and gases constantly blow from the largest vent, a crater 200 m wide. Violent eruptions have occurred in the last hundred years from cracks in the outer slopes, the last eruption was in 1958/9 (Crane 1992). The island is well forested with a moist broadleaf tropical forest over much of the southern half of the island, the northern side has more grassland, scrub and Casuarina equisetifolia reflecting younger and shallower soils. Tofua is inhabited and there are two small villages on the island, although no population was recorded for the island in the 2006 census. The villagers primarily grow kava for consumption in Tongatapu and this involves constant clearing of forest for plantations
Land use: agriculture
| IUCN Habitat | Coverage % | Habitat detail |
|---|---|---|
| Shrubland | 34 | |
| Forest | 50 | |
| Wetlands(Inland) | 16 |
Threats
Summary of threats to biodiversity at KBA: The island is inhabited and the principal activity is forest clearing for kava production. The Whitney Expedition reported feral pigs and feral dogs on the island, both of which would severely affect accessible seabird nesting colonies on the island. Habitat destruction, poaching for food and feathers, and introduced species are the principal threats to remaining Tongan biodiversity (WWF 2001). Introduced pigs, rats and cats can have catastrophic impacts on breeding seabirds and passerines. There are no national parks in Tonga and Rinke (1986b) has suggested that the greatest potential for conservation lies in the protection of uninhabited, forested, and predator-free islands such as ‘Ata, Tofua and Late that are stocked with threatened flora and fauna from inhabited islands. Paleoecology studies suggest many of the target species once occurred on these refuge islands and this approach may offer the best chance for conservation of many threatened species. Although Tofua is inhabited, it has the largest remaining area of biodiversity rich forest in Tonga, such forest is the principal habitat for Tonga’s landbirds, and as such it remains a very important conservation area.
| Threat level 1 | Threat level 2 | Threat level 3 | Timing |
|---|---|---|---|
| Agriculture & aquaculture | Annual & perennial non-timber crops | Small-holder farming | Ongoing |
| Invasive & other problematic species, genes & diseases | Invasive non-native/alien species/diseases | Named species | Ongoing |
Additional information
References: Jenkins, J.A.F. 1980. Seabird records from Tonga-an account based on the literature and recent observations. Notornis 27:205-235. Prescott, N. and P. S. Folaumoetu’i (Editors). 2004. Tonga Biodiversity Stocktaking. Technical Report 1 for the National Biodiversity Strategy and Action Plan. Dept. of Environment, Nuku’alofa. Rinke, D. 1986a. Notes on the avifauna of Niuafo’ou Island, Kingdom of Tonga. Emu 86:145-151. 1986b. The status of wildlife in Tonga. Oryx 20:146-151. 1991. Birds of ‘Ata and Late, and additional notes on the avifauna of Niuafo’ou Island, Kingdom of Tonga. Notornis 38: 131-151. Rinke, D., L.H.Soakai and A.Usback. 1993. Koe Malau: Life and future of the Malau. Brehm Fund for International Bird Conservation, Bonn. Stattersfield, A.J., M.J. Crosby, A.J. Long, and D.C. Wege. 1998. Endemic Bird Areas of the World: Priorities for biodiversity conservation. BirdLife Conservation Series no. 7, BirdLife International, Cambridge, UK. 846 pp. Steadman, D.W. 1998. Status of land birds on selected islands in the Ha’apai Group, Kingdom of Tonga. Pacific Science 52:14-34. 2006. Extinction and Biogeography of Tropical Pacific Birds. University of Chicago Press. Chicago & London. WWF 2001. www.worldwildlife.org/wildworld/profiles/terrestrial/oc/oc0114_full.html