Species

BackDisculella spirulina (Cockerell, 1921)

Disculella spirulina (Cockerell, 1921)

  • 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:
Cameron, R., Groh, K., Cuttelod, A. & Neubert, E.

Contributor/s:
Abreu, C. & Teixeira, D.

Facilitators / Compilers/s:


Assessment Rationale:

The species was originally assessed as Vulnerable in the earlier Red Lists (1994), as it had a small area of occupancy, and it was considered as Vulnerable (B and D) in subsequent revisions of the Red List categories and criteria (2000). The species Disculella spirulina was considered by Seddon (2008) to be Vulnerable B2ab(iii) (version 3.1) as it has an area of occupancy of under 60 km2, and is known from 5-10 locations along the coast. It is considered more rare than the other species of Disculella, as it is found in lower abundance at sites. Although there is still plenty of habitat suitable, the restricted distribution and habitat disturbance grant this species the status of Vulnerable (VU) D2. If part of the region was protected, then the reduced risk of disturbance would probably allow the species to be considered as Near Threatened (NT).

Geographic Range:

This species is endemic to the Madeiran archipelago, where it is restricted to the southwestern coast of Madeira, between Paul do Mar and Ponto do Pargo (Seddon 2008). There are at present between 5 and 10 locations (assuming some locations are less accessible and have not been recorded) in this small area of occupancy.

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

Population:

The population trends for this species are not known.

Habitat and Ecology

This species occurs in grassland, scrub and on rocky slopes, where it is typically found on the underside of stones and in litter at the base of crags (Seddon 2008).

Major Threat(s):

The main threats are habitat disturbance, agricultural improvement of grassland (pesticides) and fire. Building development for tourism in the region of Paul do Mar over the last ten years, has reduced the habitat quality in the area.

Conservation Actions

Habitat monitoring is required at selected sites to ensure  disturbance is not impacting the species. There are few protected areas in the range of this species, and establishment of a small area would benefit the species through reduction of the impact of development for tourism.