IUCN SSC Mid-Atlantic Island Invertebrates Specialist Group

Species

BackJanulus stephanophorus (Deshayes, 1850)

Janulus stephanophorus (Deshayes, 1850)

  • Kingdom: Animalia
  • Phylum: Mollusca
  • Class: Gastropoda
  • Order: Pulmonata
  • Family: Gastrodontidae
VU Vulnerable
IUCN Red List Status:

Countries of Occurrence:
Portugal - Madeira

Archipelago(s):
Madeira

Assessor/s:
Dinarte Teixeira
Robert A. D. Cameron
M. B. Seddon

Reviewer/s:
Allen, D.J., Groh, K. & Neubert, E.

Contributor/s:

Facilitators / Compilers/s:


Assessment Rationale:

The present species is endemic to the Madeiran Islands (Portugal), where it is found on the Island of Madeira only, at low elevations on the western part of the island and the northern coast. This species has a small area of occupancy (AOO 24 km2 ) and is only known from six sites. This is certainly a rare species, with a scattered distribution which appears to be real, based on the densities found on survey data for the last 40 years. In 2008 Seddon assessed this species as Vulnerable D2, based on five known sites and habitat degradation and loss. The potential threats include forest fires on the southern coast and habitat degradation due to increased agricultural use, landslips and urban expansion. As a consequence, the species is assessed as Vulnerable (VU) under criteria B2ab(iii) given the extremely limited distribution and rarity. 

Geographic Range:

The present species is endemic to the Madeiran Islands (Portugal), where it is found on Madeira Island only at low elevations on the western part of the island and the northern coast. This species has a small area of occupancy (AOO, 20 km2 ) and it is only known from six independent sites at distinct locations. Despite extensive survey efforts on the last 40 years, the restricted range of the species has not been expanded, with only one new site added in recent years (Ribeiera de Sao Jorge, Teixeira pers. comm. 2016)

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

Population:

The species has recently been located at a new site on the Ribeira de Sao Jorge (Teixeira pers. comm. 2016), but other than this there are no recent data on the trend.

Habitat and Ecology

The species occurs in the soil at the base of ferns and trees and amongst leaf litter on rock ledges in deep wooded ravines. It is present along the wetter coast. 

Major Threat(s):

The potential threats to the species include forest fires on the south coast and habitat degradation due to landslips and urban expansion. In the northern part of the island, the Acacia woodland is starting to get into the edge of the Laurisilva and this is likely to impact the habitats in 15 to 20 years in terms of habitat degradation. In the northwestern part of the habitat, there is a return to agriculture and this may also lead to decline in the habitats. 

Conservation Actions

Wells and Chatfield (1992) noted that Seddon (pers. comm. 1990) and Cameron (in litt. 1991) both suggested that the species should be considered as Rare. Seddon (2008) provided an assessment as Vulnerable (D2) based on five known locations. There are no known specific actions in place for this species and most of the known sites lie outside protected areas.