IUCN SSC Mid-Atlantic Island Invertebrates Specialist Group

Species

BackSerratorotula coronata (Deshayes, 1850)

Serratorotula coronata (Deshayes, 1850)

  • Kingdom: Animalia
  • Phylum:
  • Class: Mollusca
  • Order: Gastropoda
  • Family: Hygromiidae
EX Extinct
IUCN Red List Status:

Countries of Occurrence:
Portugal - Madeira

Archipelago(s):
Madeira

Assessor/s:
Seddon, M.

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

Contributor/s:

Facilitators / Compilers/s:


Assessment Rationale:

This species was originally assessed under Geomitra coronata. It was previously listed as Endangered, using the version 2.3. of IUCN criteria. It is still considered to be Endangered (EN) B1ab(ii,iii)+2ab(ii,iii), as it has two known locations, and the range and habitats are very localised, with pressures of disturbance from grazing and human recreational activities. The reproductive cycle for this species is longer than other continental equivalents, with few young produced, so species recovery is slow (Seddon, pers. comm., 2009). The previous listing as Endangered was based on similar data, and no additional sites have been recognised close to the other localities in Porto Santo (Seddon 2008). 

Geographic Range:

This species is endemic to the small island of Porto Santo in the Madeiran Archipelago. The majority of the species no longer live in their original natural habitats as the vegetation prior to human colonisation in 1419 was apparently dry forest, and today it is open grassland which is grazed (Seddon 2008). There are subfossil specimens from many parts of the island, however today it survives is two small patches of habitat on the island (Seddon 2008).

Regions:
Portugal - Madeira
Extent of Occurrence (EOO):
36 (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:

Small remnant sub-populations survive, which are very localised.

Habitat and Ecology

The species is found amongst small areas of scree on grassy slopes of two small hills on the island.

Major Threat(s):

The major threats to the species remain the very small area of surviving habitat, which is vulnerable to disturbance by grazing animals, habitat trampling and possible disturbance by shell collectors.

Conservation Actions

This species is not listed on the Habitats Directive list of protected species, although it is one of the most threatened species due to the small area of suitable habitat and the likelihood that this maybe disturbed. Research actions include habitat monitoring as a proxy for population monitoring given the likely small population size.