Assessment Rationale:

Trechus pereirai is an endemic cave adapted species known from a single island, Pico (Azores, Portugal). It has a very small extent of occurrence (EOO = 8 km²) and reduced area of occupancy (AOO = 8 km²).  The species is very rare and only known from two subpopulations (lava tubes of Furna das Cabras II and Gruta da Ribeira do Fundo). The area surrounding one of the caves is heavily impacted by human activities. A habitat management plan is needed and anticipated to be developed during the coming years. We suggest also as future measures of conservation 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 Critically Endangered (CR).

Geographic Range:

Trechus pereirai is a cave adapted endemic species from Pico (Azores, Portugal) (Borges et al. 2010), known from caves of Furna das Cabras II and Gruta da Ribeira do Fundo. The extent of occurrence (EOO) is 8 km² and the maximum estimated area of occupancy (AOO) is 8 km².

Population:

The species is very rare and only known from two subpopulations in Pico island (Amorim 2005). Species abundance may have decreased in one of the caves (Gruta da Ribeira do Fundo) as it has been used as a dump site up till recent; and the population in the the other cave where this species occurs (Furna das Cabras II) may be negatively impacted since the area surrounding the cave is suitable for forest exploitation.

Habitat and Ecology

This species occurs in two small lave tubes located in Pico island (Gruta das Cabras II and Gruta da Ribeira do Fundo) (Borges et al. 2004). It is a cavernicolous (i.e. a troglobitic species) predator and/or saprophagous species.

Major Threat(s):

The main current threats to this species are the loss of habitat quality due to human activities: garbage and solid waste dumping, and livestock farming.  However, there are several future potential threats: climatic changes (see Ferreira et al. 2016) that can change the conditions inside the caves; change in the road infrastructure around the cave; potential human recreational activities with radical cave visitation and geological events (volcanic activity and earthquakes).

Conservation Actions

The species is protected by regional law (RAA 2008). Further research is needed into its ecology and life history in order to find extant specimens.  It is necessary a monitoring plan for the invertebrate community in the habitat in order to contribute to the conservation of this species. We suggest also as future measure of conservation fencing the entrance of the cave where the species occurs. A habitat management plan is needed and anticipated to be developed during the coming years.