Countries of Occurrence:
Portugal - Madeira
Cameron, R., Groh, K., Neubert, E., Seddon, M.B., Allen, D.J. & Badia Boher, J.A
Groh, K., Seddon, M.B. & Cameron, R.
Facilitators / Compilers/s:
This species is currently known from a single locality in the Ilhéu de Baixo, which was discovered in 2014, and the species was formerly known from mainland Porto Santo, however recent surveys there (2011-2015) found no recent records, which suggests that the species could be extinct there, although, given the subterranean nature of this species, it is very difficult to be detected in surveys. The species is assessed as Critically Endangered (EN B1ab(iii)+B2ab(iii), D) based on its occurrence in a single locality, the likelihood of habitat degradation as result of landslides and the increased frequency of droughts, and a population of mature individuals of less than 50 individuals. Further research is needed to look for further subpopulations on the Islet of Baixo. Also, the protected status of Ilhéu de Baixo should provide a better likelihood of the longer-term survival of the species.
This species is endemic to the Madeiran Archipelago (Lowe 1855, Paiva 1867, Abreu and Teixeira 2008, Domingues and Alves 2016), where it was rediscovered by Teixeira in 2014 (SPNM 2016, D. Teixeira pers. comm. 2016) at a single locality on the offshore Ilhéu de Baixo. Historically, the species was known from mainland Porto Santo, however recent surveys (2011-2015) on that island suggest that the species could be extinct there, however, this is a subterranean species found in the soil, which makes it difficult to be found. All past records are from the Quaternary deposits of Zimbral da Areia (Wollaston 1878) and Pico do Maçarico, at Porto Santo (Seddon 2008). Wollaston (1878) adds further records on Madeira Island, however, the localities and the taxonomic status of the samples are uncertain.
The Ilhéu de Baixo subpopulation is estimated to have less than 50 mature individuals. There are no data on the population trend, and population monitoring might be useful to check the status of this rare species.
The species is found in ravine areas, in loose terrain and associated with grasses on Ilhéu de Baixo, under stones or buried in the soil (D. Teixeira pers. comm. 2016). A continuing decline in habitat quality is inferred from the increased frequency of droughts due to climate change.
The main threats are continuous landslides, which could lead to habitat fragmentation or loss, potential predation by native carabids (Eurygnatus latrellei latrellei and Scarites abbreviatus cimensis) and climate change, through increased frequency of drought periods (D. Teixeira pers. comm. 2016). The possible recolonization by rodents such as mice and rats, although improbable, should be taken into account.
There was a habitat restoration and predator eradication (mice Mus musculus) programme on the Baixo Islet during the LIFE "Ilhéus do Porto Santo" Project. There is an ongoing periodical monitoring scheme as part of post-LIFE project (2016-2020).