MAIISG

Assessment Rationale:

This species is only present in a small area which is under pressure from encroaching quarrying and decline in habitat quality as result of  blown sand during extreme weather events. Based on the existing information and the fact that this species occurs in one location with an area of occupancy of 4 km2,  the species is considered as Critically Endangered (CR) B2ab(iii). The past evaluation of Vulnerable was based on the same information, however the quarry has got closer to the site increasing the threats to the species.

Geographic Range:

T. arinagae occurs at two localities as a fossil/subfossil along the eastern coast of Gran Canaria, Arinaga and Playa Ojo de Garza, north of Aeropuerto de Gando. This species was found as a fossil/subfossil on the island of Fuerteventura (Ibanez et al. 1997). This species is only known living at the summit of the volcano north of Arinaga, where it occupies a narrow strip of rocky habitat above the sandy slopes (300 m x 50 m).

Population:

There is only a very small population (Groh, pers. comm., 2010).

 

Habitat and Ecology

T. arinagae is a terrestrial gastropod, known from rocky summit of volcano.

Major Threat(s):

This species has a small distribution area. The major threat on the northern side is the extraction of gravel and the extension towards the site.  A secondary threat remains from blown sand from the sandy quarry further away from the site during high winds. The presence of the military transmission mast, with the access roads permits additional traffic to the site.

Conservation Actions

This species was listed as Vulnerable (Moliner Gomez 2001), but not listed on the Canary Island Red List nor the Spanish Red List (Verdu and Galante 2009). In terms of conservation measures, the site should be protected as a Special Nature Reserve given that Theba arinagae inhabits this location and is already threatened. Restoration of the habitat is also required.