IUCN SSC Mid-Atlantic Island Invertebrates Specialist Group


BackCixius cavazoricus Hoch, 1991

Cixius cavazoricus Hoch, 1991

Cave lacehopper (English)

  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Class: Insecta
  • Order: Hemiptera Fulgoromorpha
  • Family: Cixiidae
CR Critically Endangered
IUCN Red List Status:

Countries of Occurrence:
Portugal - Azores


Danielczak, A.

Lamelas-Lopez, L.

Facilitators / Compilers/s:

Assessment Rationale:

Cixius cavazoricus is a cave lacehopper species endemic to Faial (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 genetically isolated natural subpopulations. The main threat to this species is above cave deforestation which will reduce the amount of suitable roots as food resources, increased nitrogen levels derived from the use of pesticides in neighbouring pastures and increased dryness due to climate change. We suggest as future measure 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), mostly due to fragmentation of the two subpopulations, very small EOO and AOO, declining of AOO and current high degradation of the habitat.

Geographic Range:

Cixius cavazoricus is a single island endemic cave lacehopper species restricted to Faial Island (Azores, Portugal) (Borges et al. 2010). The species only occurs in two small caves (Gruta das Anelares and Gruta do Cabeço do Canto) and recent field work failed to find it in one of the locations. Its area of occupancy is 8 km² and extent of occurrence is 8 km².

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


Cixius cavazoricus is an obligate cave species known to occur in two lava tubes in Faial Island (Azores, Portugal). The species is extremely rare since only a few specimens have been found despite the efforts in sampling it. The species was not found during a fieldwork survey in 2010 and a single specimen was found in one of the caves in May 2014. This species is assessed here as severely fragmented as at least 50% of the subpopulations exist in populations where there is little genetic exchange, and which are non viable.

Habitat and Ecology

This is a troglobitic species that only occurs in two lava tubes in Faial Island (Azores, Portugal) (Hoch 1991). The species is restricted to the deep dark cave zone, presents low dispersal ability it is known to feed on roots of the above cave vegetation.

Major Threat(s):

Cixius cavazoricus is highly threatened by above cave deforestation which reduces the food resources. Increasing nitrogen levels derived from the use of pesticides in neighbouring agricultural land are also a threat since they change the adequate cover by native trees and shrubs above ground. However, there are also 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 caves; 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), and one of the caves is in the Natural Park of Faial. Monitoring is needed to access population trends and confirm if the species is no longer present in one of its locations. Measures should be taken to prevent deforestation in the areas above the caves where this species occurs to prevent reduction of food resources for this species. A habitat management plan is needed and anticipated to be developed during the coming years.