Paludomus ajanensis 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Mollusca Gastropoda Sorbeoconcha Paludomidae

Scientific Name: Paludomus ajanensis
Species Authority: Morelet, 1860
Cleopatra ajanensis (Morelet, 1860)
Taxonomic Notes: There is one synonym: Cleopatra ajanensis (Morelet, 1860).

Assessment Information [top]

Red List Category & Criteria: Endangered B1ac(iv)+2ac(iv); D ver 3.1
Year Published: 2009
Date Assessed: 2006-01-11
Assessor(s): Gerlach, J.
Reviewer(s): Miller, R.M., Pollock, C.M. & Seddon, M.B.
This species is assessed as Endangered because its population is estimated to be only 100 adults; a single pollution event in 2002 caused a 20% decline in populations and numbers. The remaining populations undergo extreme fluctuations in the number of mature individuals, most likely due to floodwaters causing periodic high mortality. In addition, the species' extent of occurrence (EOO) is estimated to be 15 km², its area of occupancy (AOO) is 1 km² and it is found in only three locations. It is therefore listed as Endangered, EN B1ac(iv)+2ac(iv); D.
Previously published Red List assessments:
2000 Critically Endangered (CR)
1996 Endangered (EN)

Geographic Range [top]

Range Description: This snail species is endemic to the Seychelles islands of Mahé (Riviere Cascade, Le Niol) and Silhouette (Grande Riviere, Riviere Macabee and west of Mt. Dauban). A record from Somalia is believed to be erroneous.
Countries occurrence:
Seychelles (Seychelles (main island group))
Estimated area of occupancy (AOO) - km2: 1
Continuing decline in area of occupancy (AOO): No
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) - km2: 15
Continuing decline in extent of occurrence (EOO): No
Extreme fluctuations in extent of occurrence (EOO): No
Number of Locations: 3
Continuing decline in number of locations: No
Extreme fluctuations in the number of locations: No
Lower elevation limit (metres): 250
Upper elevation limit (metres): 250
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: In 1994, four populations were known and the total population size was estimated to be 125 individuals. There was a 20% decline in 2002 due to loss of one site, and the associated subpopulations, to pollution. Since 2002, only three sites have been occupied, with a total population of approximately 100 adults.
Current Population Trend: Stable
Additional data:
Number of mature individuals: 100 Continuing decline of mature individuals: No
Extreme fluctuations: Yes Population severely fragmented: No

Habitat and Ecology [top]

Habitat and Ecology: This snail inhabits mid-altitude, shallow, gravel-based pools in high altitude streams (240-250 m a.s.l.).
Systems: Freshwater
Continuing decline in area, extent and/or quality of habitat: No

Threats [top]

Major Threat(s): Pollution has caused the loss of one of the sites the species inhabited. The remaining populations are currently secure from this threat, but vulnerable to changes in water conditions caused by development or habitat change.

Conservation Actions [top]

Conservation Actions: No conservation action has been taken. Legal protection of Silhouette island is required to protect 75% of the known populations. Research is also needed into the species' life history and ecology.

Citation: Gerlach, J. 2009. Paludomus ajanensis. The IUCN Red List of Threatened Species 2009: e.T40092A10305222. . Downloaded on 01 December 2015.
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