Assessment Rationale:

Seddon (2008) noted that this species is close to meeting the criteria for Near Threatened (version 3.1), as it occurs at over 15 sites with known area of occupancy exceeding 60 km². However, there is no evidence of declining quality of habitat over the last 15 years, and the laurisilva forest in the centre of the island is protected. The region may be subject to changing micro-climate as the result of increased movement of water through use of levada water for generation of electricity. Given the lack of current threats, the species is assessed as Least Concern.

Geographic Range:

This species is endemic to Madeira, where it is found mainly in the central laurisilva forests and on the north coast between São Vicente and Porto Moniz (Seddon 2008).

Population:

There are no recent data to establish population trends, but it is believed to be stable.

Habitat and Ecology

It is often found on wet rock faces and crags resting on Marchantia and dripping grasses in laurisilva forests, usually in the spray zone near waterfalls.

Major Threat(s):

The species is found on rock ledges on large crags and on rocky slopes and hence habitat degradation (blasting crags during road enlargement schemes) and changes to the damp habitats (fire, extraction of water) are two of the major threats to these species.

Conservation Actions

No conservation areas have yet been designated for Leiostyla irrigua. Further research is needed to establish whether there is a clinal range with other similar species, and studies are ongoing (Cameron and Pokrysko, pers. comm., 2010). The range of the species lies partly in the Special Protected Area (Laurisilva de Madeira).