Species

BackDiscula tectiformis (Sowerby, 1824)

Discula tectiformis (Sowerby, 1824)

  • Kingdom: Animalia
  • Phylum:
  • Class: Mollusca
  • Order: Gastropoda
  • Family: Hygromiidae
EN Endangered
IUCN Red List Status:

Countries of Occurrence:
Portugal - Madeira

Archipelago(s):
Madeira

Assessor/s:
Seddon, M.B.

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

Contributor/s:

Facilitators / Compilers/s:


Assessment Rationale:

This species has a total extent of occurrence of 42 km2 with the four isolated sub-populations, three on a small hillslope area at the eastern part of the island. The habitat has been subject to changing land-use practice, and declined in quality over the last thirty years. The main range remains vulnerable to rodent predation, fires and other land management changes. It has been assessed as Endangered (EN) B1a b(iii).l

Geographic Range:

This species is endemic to Porto Santo. There are records from the mainland where the species is now largely restricted to the east end of the island, but fossils show it was formerly widespread (Cameron et al. 2006). This species has a total area of occupancy of 16 km2 with the three isolated sub-populations, on two different hillslope areas at the eastern part of the island, and another at west end of the mainland opposite Ilheu de Baixo.

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

Population:

There is no recent population trend data for this species. It is known to be impacted by rodent predation.

Habitat and Ecology

This species occurs in grassland with herbs, on coastal cliffs, rocky slopes and summits. The habitat has been subject to changing land-use practice, and declined in quality over the last thirty years. The site behind the harbour and at the west end of the island are the most vulnerable populations.

Major Threat(s):

These small populations are vulnerable to rodent predation, fires and other habitat loss from tourist developments (hotels, recreational areas, roads).

Conservation Actions

None of the range falls within a designated protected area. Conservation actions include habitat monitoring for indication of population trends, as well as population monitoring to establish impact of the predation on the species.