BackTrechus isabelae Borges & Serrano, 2007

Trechus isabelae Borges & Serrano, 2007

Cave ground beetle (English)/ Carocho cavernicola (Portuguese)

  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Class: Insecta
  • Order: Coleoptera
  • Family: Carabidae
VU Vulnerable
IUCN Red List Status:

Countries of Occurrence:
Portugal - Azores


Danielczak, A.

Lamelas-Lopez, L.

Facilitators / Compilers/s:

Assessment Rationale:

Trechus isabelae is an endemic cave adapted species known from a single island, S. Jorge (Azores, Portugal) and volcanic pit. 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 natural subpopulation. However, there are no known current threats for this species, since the volcanic pit where it occurs is in a difficult to access site and located in a protected area. The species is assessed as Vulnerable (VU) with criteria D2 due to potential future threats namely climatic changes with alteration of environmental conditions in the cave, potential human recreational activities, geological events and changes in the management of the surrounding area. These threats could feasibly result in the movement of this species to CR or EX in a very short amount of time.

Geographic Range:

Trechus isabelae is a single island endemic cave adapted species restricted to S. Jorge (Azores, Portugal) (Borges et al. 2010), known from a single cave, the volcanic pit Algar do Morro Pelado (Pereira et al. 2016) located within the regionally protected area of Pico da Esperança e Planalto Central. The extent of occurrence (EOO) is 4 km² and the maximum estimated area of occupancy (AOO) is 4 km².

Portugal - Azores
Extent of Occurrence (EOO):
4 (km2)
Area of Occupancy (AOO):
4 (km2)
Elevation Lower Limit:
1000 (m)
Elevation Upper Limit:
1000 (m)
Biogeographic Realms:
Endemic Azores


The species is very rare and only known from a single subpopulation. The cave where the species occurs is located in a protected area and of difficult access and we assume no current impact for the population.

Habitat and Ecology

This species occurs in a volcanic pit (Algar do Morro Pelado, S. Jorge island) of great dimensions (140 m deep) located at 1000 m Asl. The surrounding area consists of natural grassland (Borges et al. 2007). It is a cavernicolous (i.e. a troglobitic species) predator and/or saprophagous species.

Major Threat(s):

No threats are currently available, since the volcanic pit is located in an inaccessible area and the area is protected. However, there are several future potential threats: climatic changes (see Ferreira et al. 2016) that can change the conditions inside the volcanic pit; change in the road infrastructure around the cave; potential human recreational activities with radical cave visitation; reforestation of the area with exotic trees with unknown impact and geological events (volcanic activity, earthquakes and landslides).

Conservation Actions

The species is protected by regional law (RAA 2011). Its habitat is in a regionally protected area (Natural Park of S. Jorge, within the regionaly protected area of Pico da Esperança e Planalto Central). 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. A habitat management plan is needed and anticipated to be developed during the coming years.