IUCN SSC Mid-Atlantic Island Invertebrates Specialist Group

Species

BackLeiostyla calathiscus (R.T. Lowe, 1831)

Leiostyla calathiscus (R.T. Lowe, 1831)

  • Kingdom: Animalia
  • Phylum:
  • Class: Mollusca
  • Order: Gastropoda
  • Family: Lauriidae
NT Near Treatened
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.

Facilitators / Compilers/s:


Assessment Rationale:

This species has an small area of occupancy of 14 km2, with four known locations. Some sites are vulnerable to declining quality of habitat due to development for tourism on the island. However, the species lies in plantations on the summits, and so as these habitats are still present after 50 years with the species in abundance, this suggests that the species may merit a lower status than Vulnerable D2 on the basis of its small range and limited threats to the habitat. Revised assessment as Near Threatened (NT), almost meeting criteria B.

Geographic Range:

This species is endemic to Porto Santo. Wollaston (1878) found L. calathiscus on the summits of Pico Branco and Pico do Facho. This species can still be found on Pico de Facho, Pico Branco and Pico de Castello (Seddon 2008). Fossil shells have been obtained from Porto do Frades, Porto do Morena and the Fonte de Areia; this species must have been present since the Late Pleistocene and during the late Weichelselian it was more common at lower altitudes (Cameron et al. 2006).

Regions:
Portugal - Madeira
Extent of Occurrence (EOO):
(km2)
Area of Occupancy (AOO):
14 (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, although the species can be abundant when present in some habitats (Seddon, pers. comm., 2010).

Habitat and Ecology

This species is usually found in the leaf-litter around the base of the trees and low crags or on dead branches and occasionally in crevices on crags. Generally it was found in association with L. monticola in the old conifer plantations.

Major Threat(s):

As this region is subject to tourist activities, the habitat is changing, which might affect the species. Other possible threats come from deforestation, as some sites are in plantations.

Conservation Actions

This species has sparse distribution on Porto Santo, so recommended conservation actions include management of the known sites areas for maintenance of this species and monitoring of the protected areas to ensure no loss of further habitat and subpopulations.