IUCN SSC Mid-Atlantic Island Invertebrates Specialist Group

Species

BackHystricella turricula Lowe, 1831

Hystricella turricula Lowe, 1831

Cima Discula

  • Kingdom: Animalia
  • Phylum:
  • Class: Mollusca
  • Order: Gastropoda
  • Family: Hygromiidae
VU Vulnerable
IUCN Red List Status:

Countries of Occurrence:
Portugal - Madeira

Archipelago(s):
Madeira

Assessor/s:
Seddon, M.B.

Reviewer/s:
Groh, K., Cameron, R., Cuttelod, A. & Neubert, E.

Contributor/s:
Cameron, R.

Facilitators / Compilers/s:


Assessment Rationale:

Seddon (2008) suggested a revised assessment of Critically Endangered B1ab(iii) (version 3.1) given the survey work by Cook and Cameron (1999-2001; Cameron, pers. comm, 2010) confirming the small extent of occurrence (under 10 km2) and declining quality of habitat. However the offshore islet where it is present is now protected, and hence the quality of habitat is probably not declining over the whole range of the species and a lower risk of extinction is now thought more appropriate, hence it is confirmed as listed as Vulnerable D2; no change from previous Red List assessments.

Geographic Range:

This species is endemic to the Madeiran islands: it is restricted to the islet of Ilheu de Cima, south-east of the main island of Porto Santo (Seddon 2008).

Regions:
Portugal - Madeira
Extent of Occurrence (EOO):
(km2)
Area of Occupancy (AOO):
8 (km2)
Elevation Lower Limit:
(m)
Elevation Upper Limit:
(m)
Biogeographic Realms:
Palearctic
Presence:
Extant
Origin:
Endemic Madeira
Seasonality:
Resident

Population:

This species is only present on an offshore islet and there are no recent data on population trends.

Habitat and Ecology

This species is found beneath large blocks of basalt scattered on the grassy slopes (Seddon 2008).

Major Threat(s):

Although the vegetation on the island has been subjected to grazing, at present the levels of threat to the species are uncertain. Any activity that disturbs the vegetation around the basalt blocks where the species is found could lead to disturbance of the species.

Conservation Actions

This species is listed on the EU Habitats and Species Directive Annex II and the Council of Europe Bern Convention Appendix 2. At present the range lies in a protected area. Further research on habitat status and monitoring would be recommended for this species which is found in a protected area.