MAIISG

Assessment Rationale:

Turinyphia cavernicola is a single island endemic restricted to the Island of Terceira (Azores, Portugal). It has a very small Extent of Occurrence (EOO = 8 km²) and Area of Occupancy (AOO = 8 km²). The species is very rare and only known from three isolated natural subpopulations. The main current threats to this species are cave visitation by tourists and the impact of agriculture activities. We propose the regular monitoring of the species (every ten years) and fencing the entrances of the caves where human intrusion and disturbance has been occurring. The species is assessed as Endangered (EN), mostly due to its small Extent of Occurrence (EOO) and Area of Occupancy (AOO) and the decline of habitat quality.

Geographic Range:

This is a single island endemic restricted to the Island of Terceira, Azores, Portugal (Borges et al. 2010). The species was originally described from a single cave, the volcanic show pit Algar do Carvão, and later also found in two lava tubes, Gruta da Malha and Furna de Santa Maria, that are located nearby (Pereira et al. 2016). The Extent of Occurrence (EOO) is 8 km2 and the maximum estimated Area of Occupancy (AOO) is 8 km2 .

Population:

Three subpopulations are known on the island, but two of them are very small and located in disturbed lava tubes. The single large subpopulation is located in the show cave Algar do Carvão, which is under intensive pressure due to increasing levels of visitation in the last ten years. Current Population Trend: Decreasing. 

Habitat and Ecology

The species is a troglobite specialist occuring only in humid lava tubes and volcanic pits. The species builds sheet-webs across small holes in volcanic basaltic rock. It usually occurs from twilight conditions near cave openings to deep parts of the caves (Borges and Wunderlich 2008). In the main pit-cave of Algar do Carvão, the construction of the lateral walls of the stairs with stones from the cave allowed the creation of additional supports for the webs. Systems: Terrestrial.

Major Threat(s):

The main current threats to this species are cave visitation by tourists and the impact of agriculture activities. However, there are several future potential threats: climatic changes (see Ferreira et al. 2016) that can change the conditions inside the caves; spread of plantations of Cryptomeria japonica; change in the road infrastructure around the caves; potential human recreational activities with radical cave visitation; and geological events (volcanic activity).

Conservation Actions

The species is protected by regional law (RAA 2008). An area of 40.5 ha around Algar do Carvão was classified as “Regional Natural Monument” by the Regional Decree nr 9/2004/A, of March 23rd 2004, due to its unique volcanic features and its environmental importance. Since pasture intensification is one main threat, it might be important to safeguard the species' survival in the future, and conservation should be extended beyond the current area, possibly allowing the recovery of other caves to original conditions where the species might be reintroduced. Further research is needed into its ecology and life history in order to find extant specimens in additional lava tubes. An area-based management plan is also necessary for the caves, including invertebrate monitoring to contribute to a potential species recovery plan.