Map_thumbnail_large_font

Samoana burchi 

Scope: Global
Language: English
Status_ne_offStatus_dd_offStatus_lc_offStatus_nt_offStatus_vu_offStatus_en_offStatus_cr_onStatus_ew_offStatus_ex_off

Translate page into:

Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Mollusca Gastropoda Stylommatophora Partulidae

Scientific Name: Samoana burchi Kondo, 1973
Common Name(s):
English Burch's tree snail, Polynesian Tree Snail
Taxonomic Notes: High altitude species in the wild misidentified as S. attenuata but recently reclassified as S. burchi after molecular analysis (O'Foighil pers. comm.)

Assessment Information [top]

Red List Category & Criteria: Critically Endangered B2ab(iii) ver 3.1
Year Published: 2012
Date Assessed: 2011-09-12
Assessor(s): O'Foighil, D.
Reviewer(s): Barker, G., Cowie, R., Triantis, K., García, N. & Pippard, H.
Contributor(s): Coote, T.
Justification:
The species has only been recorded from two distinct and fragmented locations at Mount Aorai and Atara. Both subpopulations are directly threatened by the invasive predator E. rosea. The area of occupancy has been estimated to be approximately 8 km², and there is evidence of a continuing decline in this area of occupancy, as well as in the quality of the habitat due to invasive species and habitat modification. The species is listed as Critically Endangered.

Continued biosecurity vigilance is critical to prevent further invasive species establishments in this species' habitat. Surveys to determine the current distribution of this species and population size, status and trends are also recommended, as is monitoring of habitat and threats from invasive predators.

Previously published Red List assessments:

Geographic Range [top]

Range Description:This species is endemic to the montane forests of the island of Tahiti, Society Islands. According to Kondo (1973), it was first sampled (but unidentified) in the early 1930s between 1,300 and 1,500 m altitude on the slopes of Mt. Aorai (Tahiti Nui, elevation 2,066 m). In 1970, it was sampled at an altitude of 985 m in the Haoma highlands (Tahiti-Iti), the type locality. The linear distance between the Tahiti-Nui and Tahiti-Iti sites is 35 km (Kondo 1973).

In 2005, Trevor Coote biopsied additional specimens on Mt. Aorai and at approximately 1,000 m altitude on Mt. Atara (Tahiti-Iti) that were positively identified as Samoana burchi using molecular markers as well as diagnostic shell characters (Lee et al. 2009). The species therefore survives in at least one montane forest location in each of the two Tahitian peninsulas, being absent from the intervening low altitude habitat. However, we know very little concerning the actual population size or the extent of its distribution throughout Tahitian montane forests.
Countries occurrence:
Native:
French Polynesia (Society Is.)
Additional data:
Estimated area of occupancy (AOO) - km2:8Continuing decline in area of occupancy (AOO):No
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:
Continuing decline in extent of occurrence (EOO):NoExtreme fluctuations in extent of occurrence (EOO):No
Number of Locations:2Continuing decline in number of locations:No
Extreme fluctuations in the number of locations:NoLower elevation limit (metres):800
Upper elevation limit (metres):2200
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:No specific information on population is available. It is confirmed as existing in two montane locations: Mt. Aorai (Tahiti-Nui) and Mt. Atara (Tahiti-Iti).
Current Population Trend:Unknown
Additional data:
Extreme fluctuations:NoPopulation severely fragmented:Yes
All individuals in one subpopulation:No

Habitat and Ecology [top]

Habitat and Ecology:The species was recorded from high altitude cloud forest.
Systems:Terrestrial
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):0-3
Congregatory:Congregatory (and dispersive)

Use and Trade [top]

Use and Trade: There is no known use or trade.

Threats [top]

Major Threat(s):

The primary threat to this species is posed by the introduced predatory land snail Euglandina rosea. The predator has extirpated most Tahitian valley partulid populations since its introduction in 1975 (Coote and Loève 2003, Coote 2007) and extends at least to an altitude of 1,400 m into the montane forests (Lee et al. 2008 and 2009, Gargominy 2008). Lower elevation populations are therefore directly exposed to the predator, however, it is not clear how serious that exposure is in reality. Persistence of montane Partula otaheitana populations in the presence of E. rosea (Lee et al. 2009) implies that the predator may be relatively ineffective at these altitudes, as predicted by Gerlach (1994), and that native taxa may experience an altitudinal refuge (Gargominy 2008, Lee et al. 2009). Montane Tahitian habitats are relatively inaccessible and undisturbed; but there is some loss of habitat due to anthropogenic action, especially fire (Gargominy 2008).

Conservation Actions [top]

Conservation Actions: Field work to define the current distribution of this species, as well as research on its population status and trends, is required. Identification of priority sites for species conservation (e.g. key biodiversity areas that include threatened land snails) and reducing the impacts of human activities, and invasive species, is also urgently needed

Citation: O'Foighil, D. 2012. Samoana burchi. The IUCN Red List of Threatened Species 2012: e.T168195A1185169. . Downloaded on 18 September 2018.
Disclaimer: To make use of this information, please check the <Terms of Use>.
Feedback: If you see any errors or have any questions or suggestions on what is shown on this page, please provide us with feedback so that we can correct or extend the information provided