The EBA comprises the 78 islands of the Tuamotu archipelago, which stretch over nearly 1,500 km² of ocean, and the nine Gambier Islands to the south-east. All politically part of French Polynesia, which is an overseas territory of France (see also EBAs 211-213, and Secondary Area s136). Makatea and Niau are raised atolls, other islands are low atolls, not more than 7 m above sea-level, while Mangareva and some small islets in the Gambier Islands are volcanic.

The native vegetation, mostly Pandanus, Pisonia and Cordia scrub, has now been largely replaced with coconut plantations on many atolls (Davis et al. 1986); the flora of Makatea is rich compared to that of other islands with a dry forest interior.

Most of the restricted-range species are forest and scrub birds, but a number occur in coconut plantations. Prosobonia cancellata, Gallicolumba erythroptera and Ptilinopus coralensis were formerly widespread on the low atolls, but only the last of these is now present on more than a few islands. Vini peruviana was also widespread in the northern Tuamotus, but now occurs at fewer islands. The three raised islands on the other hand have (or had) localized endemics or near-endemics, with Ducula aurorae and Ptilinopus chalcurus at Makatea, Todirhamphus gambieri gertrudae at Niau and (formerly) Todirhamphus gambieri gambieri at Mangareva. Another species, Lanius gambieranus (perhaps actually an endemic Acrocephalus warbler), from the Gambier Islands was described in 1844, but the specimen is apparently lost (D. T. Holyoak in litt. 1996).

In general, information on distribution and population is sparse, as might be expected in an island EBA which covers such a wide region of ocean. Indeed, many of the islands where restricted-range species were recorded by the Whitney Expedition in 1921-1923 have not been visited since, and c.20 atolls have never been ornithologically surveyed at all. There is little recent information for Prosobonia cancellata and Gallicolumba erythroptera in particular.

The conservation situation in the Tuamotus is perhaps slightly more favourable than that in other French Polynesian archipelagos as a result of their geographic spread, isolation, difficulty of access and low human population. However, a few metres rise in sea levels (as now predicted) will quite likely cause the extinction of the rarer species.

In common with many other small-island areas, predation by introduced rats (particularly black rat Rattus rattus) is a current serious threat: for example, Prosobonia cancellata is found only on islands free from this pest, and it is also likely that rats have been responsible for the extinction of Gallicolumba erythroptera from many islands (Seitre and Seitre 1991).

Habitat destruction was a problem on Makatea, where phosphate mining (1917-1964) had confined the entire populations of Ducula aurorae and Ptilinopus chalcurus to the remaining inner forest (c.10 km² in total). These species are, however, relatively common today, with stable populations, and it is likely that they will extend their ranges as the vegetation recovers. The extinction of Vini peruviana, a habitat generalist, from Makatea is more likely the result of a particularly violent hurricane and/or the introduction of predators rather than being due to mining activities (Thibault and Guyot 1987), and illustrates the permanent vulnerability of small-island species to chance events.

Mururoa and Fangataufa atolls in the south-east of the Tuamotus have been used by France for nuclear tests since 1966 (most recently in 1995-1996, but subsequently stopped), and it is likely that these activities will have extirpated populations of Acrocephalus atyphus on Fangataufa at least (J. C. Thibault in litt. 1996).

The Tuamotus lie within the wintering range of the threatened (Vulnerable), restricted-range Bristle-thighed Curlew Numenius tahitiensis, which breeds in Western Alaska (Secondary Area s002). A tentative estimate of c.600 birds was made for the northern Tuamotus in 1989 (Lovegrove et al. 1989); as this represents some 6% of the total population, these islands are clearly important sites for the conservation of the species.

Taiaro Atoll was established as a Strict Nature Reserve in 1977; Ptilinopus coralensis was seen here in 1972 and Acrocephalus atyphus has also been recorded (Holyoak and Thibault 1984).

Recommended citation
BirdLife International (2024) Endemic Bird Area factsheet: Tuamotu archipelago. Downloaded from https://datazone.birdlife.org/eba/factsheet/215 on 23/11/2024.