IUCN SSC Mid-Atlantic Island Invertebrates Specialist Group

Species

BackBalea nitida Mousson, 1858

Balea nitida Mousson, 1858

Snail

  • Kingdom: Animalia
  • Phylum:
  • Class: Mollusca
  • Order: Gastropoda
  • Family: Clausiliiae
NT Near Treatened
IUCN Red List Status:

Countries of Occurrence:
Portugal - Azores

Archipelago(s):
Azores

Reviewer/s:
Groh, K., Seddon, M.B. & Badia Boher, J.A.

Contributor/s:

Facilitators / Compilers/s:


Assessment Rationale:

This species is endemic to the Azores Islands, where it is found on Ilha das Flores and Corvo Islet. This species is found on rocks in Laurisilva and Pittosporum woodland, on walls and alongside roads in Hydangea bushes. The species may be under-recorded in Flores, and hence it is estimated to occur at nine to 20 locations. There is a possibility that there is competitive interaction with Balea sarsii based on the balance of frequencies between both species in a survey (Cameron pers. comm. 2016). As a consequence, the species is assessed as Near Threatened (NT). Further research is recommended to look for further locations of the species in Flores Island, as well as population monitoring on both islands. 

Geographic Range:

This species is endemic to the Azores Islands (Portugal), in the eastern Atlantic Ocean. On Ilha das Flores it is found on the lower altitudes on the western, northern and eastern coasts (Frias Martin 2008, Atlas data). It is also known from Corvo Islet, from one site (Frias Martin, pers. comm. 2016). It was present at seven out of 18 sampling sites on Flores (Cameron pers. comm. 2016). It is possible that there are other locations on Flores, and as such it is estimated as nine to 20 locations.

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

Population:

There are little data on the population status on the Azores Island. Cameron (pers. comm. 2016) noted that the species was found at seven out of 18 sampling sites. The population trend is unknown, but possibly declining (Cameron pers. comm. 2016). The population density was not high at sampled sites.

Current Population Trend: Decreasing

Habitat and Ecology

This species is found on rocks in woodland, on walls and alongside roads in Hydangea bushes. Also found in Laurisilva and Pittosporum forests.

Systems: Terrestrial 

Major Threat(s):

There is a possibility that there is competitive interaction with Balea sarsii based on the balance of frequencies between both species in a survey (Cameron pers. comm. 2016).

Conservation Actions

Specimen collection is regulated on Ilha das Flores. It is found partly within a protected area, but there are no known conservation actions in place for the species. Monitoring of known populations on Flores and Corvo to establish whether the species is still present is recommended.