IUCN SSC Mid-Atlantic Island Invertebrates Specialist Group

Species

BackDiscula rotula (R.T. Lowe, 1831)

Discula rotula (R.T. Lowe, 1831)

  • Kingdom: Animalia
  • Phylum:
  • Class: Mollusca
  • Order: Gastropoda
  • Family: Hygromiidae
LC Least Concern
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. & Neubert, E.

Contributor/s:

Facilitators / Compilers/s:


Assessment Rationale:

This species is present over most of the eastern part of the island, however the total extent of occurrence is 16 km2 and the species  is vulnerable to predation by small rodents, so Seddon (2008) suggested the species should be assessed as Near Threatened.  The habitat has been subject to changing land-use practice, and as such the quality of the habitat has declined over the last thirty years, although the main area falls within a designated protected area and the species is abundant within its range. Given the current range, the habitats which have stabilised  and the current stable situation, the species assessment is revised as Least Concern (LC).

Geographic Range:

This species is endemic to the Madeiran islands, where is only found on Porto Santo on the hills at the eastern end of the island, but where it is abundant (Seddon 2008).

Regions:
Portugal - Madeira
Extent of Occurrence (EOO):
16 (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 data on population trends, however the species was recorded as local but abundant in 1980-1990's (Seddon 2008).

Habitat and Ecology

This species is usually found besides and under rocks on grassland slopes.

Major Threat(s):

The habitat has been subject to changing land-use practice, and as such the quality of the habitat has declined over the last thirty years (Seddon 2008) and the species is vulnerable to predation by small rodents.

Conservation Actions

Survey on the impact of rodents on adult populations as well as control of rodents are recommended.