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Stylodonta studeriana 

Scope: Global
Language: English
Status_ne_offStatus_dd_offStatus_lc_offStatus_nt_offStatus_vu_offStatus_en_onStatus_cr_offStatus_ew_offStatus_ex_off

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Mollusca Gastropoda Stylommatophora Acavidae

Scientific Name: Stylodonta studeriana (Ferussac, 1821)

Assessment Information [top]

Red List Category & Criteria: Endangered B1ab(iii)+2ab(iii) ver 3.1
Year Published: 2009
Date Assessed: 2006-01-11
Annotations:
Needs updating
Assessor(s): Gerlach, J.
Reviewer(s): Pollock, C.M., Miller, R.M. & Seddon, M.B.
Justification:
Although populations are stable, this species has a highly restricted distribution, with an EOO and AOO of only 12 km². It is found in 4 locations. Within this area, it is vulnerable to habitat degradation and fire. Habitat quality is declining, due to invasion by introduced plants, especially Cinnamomum verum. This species is protected within Praslin National Park, but threats to the species' habitat are ongoing.

Geographic Range [top]

Range Description:This snail is endemic to the Seychelles, and is found only on the granitic island of Praslin. Historically it was found on the islands of Curieuse and La Digue, but it is extinct on both islands today. Both its extent of occurrence (EOO) and its area of occupancy (AOO) have been estimated at 12 km².
Countries occurrence:
Native:
Seychelles (Seychelles (main island group))
Additional data:
Estimated area of occupancy (AOO) - km2:12Continuing decline in area of occupancy (AOO):No
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:12
Continuing decline in extent of occurrence (EOO):NoExtreme fluctuations in extent of occurrence (EOO):No
Number of Locations:4Continuing decline in number of locations:No
Extreme fluctuations in the number of locations:NoLower elevation limit (metres):100
Upper elevation limit (metres):300
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:In 2005, the population on Praslin island was estimated at 12,000 individuals.
Current Population Trend:Stable
Additional data:
Number of mature individuals:12000Continuing decline of mature individuals:No
Extreme fluctuations:No

Habitat and Ecology [top]

Habitat and Ecology:This is an arboreal species found in moist lowland woodland areas from 100-300 m, especially on palm trees. It is viviparous: the females give birth to live young, rather than laying eggs.
Systems:Terrestrial
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):5

Threats [top]

Major Threat(s): Habitat degradation and fire threatens this snail throughout its small range. While small-scale farming, resulting in habitat degradation, was a threat in the past, invasive exotic plant species (e.g., Cinnamomum verum) have and continue to directly impact this species' habitat. The impact of these exotic species is expected to remain a threat into the future. Fire is also a minor threat.

Conservation Actions [top]

Conservation Actions: This snail is present and protected in Praslin National Park. Restoration within Praslin National Park is recommended. Invasive species in the Seychelles must be controlled.

Citation: Gerlach, J. 2009. Stylodonta studeriana. The IUCN Red List of Threatened Species 2009: e.T168105A6450150. . Downloaded on 23 September 2017.
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