Assessment Rationale:

Trechus oromii is an endemic cave adapted species known from a single island, Faial (Azores, Portugal). It has a very small extent of occurrence (EOO = 4 km²) and  reduced area of occupancy (AOO = 4 km²). The species is very rare and only known from a single subpopulation. The area surrounding the cave 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 entrance of the cave where the species occurs. The species is assessed as Critically Endangered (CR).

Geographic Range:

Trechus oromii is a cave adapted endemic species known from Faial (Azores, Portugal) (Borges et al. 2010), occurring in only one lava tube cave (Gruta do Parque do Capelo). The extent of occurrence (EOO) is 4 km² and the maximum estimated area of occupancy (AOO) is 4 km².

Population:

The species is very rare and only known from a single subpopulation in Faial island. The area surrounding the cave is heavily impacted by human disturbance.

Habitat and Ecology

This species occurs inside of a small lave tube located in the Nature Reserve & Recreational Park of Capelo (Faial island) (Borges et al. 2004; Amorim 2015). 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 recreational cave visitation and impact of the management of the Nature Reserve & Recreational Park where the cave is located. However, there are several future potential threats: climatic changes (see Ferreira et al. 2016) that can change the conditions inside the cave; change in the road infraestructure 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). Its habitat is in a regionally protected area (Natural Park of Faial). 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 as future measure of conservation the fencing the entrances of the caves where human intrusion and disturbance has been occurring. A habitat management plan is needed and anticipated to be developed during the coming years.