Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Mollusca Gastropoda Stylommatophora Partulidae

Scientific Name: Partula otaheitana
Species Authority: Bruguière, 1792
Common Name(s):
English Polynesian Tree Snails
Taxonomic Notes: This species has controversial taxonomy made more confusing by widespread extinctions of varieties. It is likely that more than one species is involved. Eight subspecies are recognised by Crampton (1916); maybe two are extant in the wild.

Assessment Information [top]

Red List Category & Criteria: Critically Endangered B2ab(ii,iii) ver 3.1
Year Published: 2009
Date Assessed: 2007-10-20
Assessor(s): Coote, T.
Reviewer(s): Cowie, R. & Seddon, M.B.
After the introduction of the carnivorous snail Euglandina rosea to Tahiti in 1977 populations and species began to disappear rapidly as a result of predation. This species disappeared from low altitudes on the main island of Tahiti Nui but small isolated populations persisted in a few places above 1000 m and in one area of Taiarapu Peninsula. These populations were found in surveys in the 1990s and during the intensive surveys of 2003–2005, as well as by botanists during expeditions.
Previously published Red List assessments:
1996 Critically Endangered (CR)
1994 Extinct (Ex)

Geographic Range [top]

Range Description: The species is endemic to Tahiti. Formerly it had a widespread distribution across the island but now it is restricted to the highest altitudes.
Countries occurrence:
French Polynesia (Society Is.)
Estimated area of occupancy (AOO) - km2: 1-10
Continuing decline in area of occupancy (AOO): Yes
Estimated extent of occurrence (EOO) - km2:
Lower elevation limit (metres): 95
Upper elevation limit (metres): 1800
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: It is difficult to assess population sizes because of inaccessible terrain.
Current Population Trend: Decreasing
Additional data:
Population severely fragmented: Yes

Habitat and Ecology [top]

Habitat and Ecology: All remaining populations of this species are restricted to high altitudes (above 950 m) and the associated cloud forest habitat. Before the arrival of Euglandina rosea this species was found in all the valleys at base altitude.
Systems: Terrestrial
Continuing decline in area, extent and/or quality of habitat: Yes

Threats [top]

Major Threat(s): Euglandina rosea remains the principal threat but appears to be less effective a predator at high altitude. That said, some of the populations are seriously threatened. There is also increasing habitat damage due to communications installation and roadside clearances to facilitate better views for tourists in one of the best areas.

Conservation Actions [top]

Conservation Actions: Because of the taxonomic uncertainties and the genetic uniqueness of certain populations there is an urgent need to initiate ex-situ breeding populations. However, for the moment the populations are not considered robust enough to remove the numbers required.

Citation: Coote, T. 2009. Partula otaheitana. The IUCN Red List of Threatened Species 2009: e.T16321A5601670. . Downloaded on 10 October 2015.
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