Biodiversity Data Journal :
Species Conservation Profiles
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Corresponding author: Paulo Alexandre Vieira Borges (pborges@uac.pt)
Academic editor: Pavel Stoev
Received: 18 Dec 2018 | Accepted: 04 Apr 2019 | Published: 24 Apr 2019
© 2019 Paulo Borges, Lucas Lamelas-Lopez, Isabel Amorim, Anja Danielczak, Mário Boieiro, Carla Rego, Sophie Wallon, Rui Nunes, Pedro Cardoso, Axel Hochkirch
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Borges P, Lamelas-Lopez L, Amorim I, Danielczak A, Boieiro M, Rego C, Wallon S, Nunes R, Cardoso P, Hochkirch A (2019) Species conservation profiles of cave-dwelling arthropods from Azores, Portugal. Biodiversity Data Journal 7: e32530. https://doi.org/10.3897/BDJ.7.e32530
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Azorean volcanic cave biodiversity is under considerable pressure due to ongoing threats of pollution, land use change, touristic activities or climate change. In this contribution, we present the IUCN Red List profiles of 15 cave-adapted arthropod species, endemic to the Azorean archipelago, including species belonging to the speciose genus Trechus (Carabidae), which is represented in Azores by seven species. The objective of this paper is to assess all endemic Azorean cave-adapted species and advise on possible future research and conservation actions critical for the long-term survival of the most endangered species.
Most species have a restricted distribution (i.e. occur in one or two caves), very small extent of occurrence (EOO) and a small area of occupancy (AOO). A continuing decline in the number of mature individuals is inferred from the ongoing cave habitat degradation. The two troglobitic species of the homopteran genus Cixius are in great danger of extinction due to major land-use changes in epigean habitats above their known localities. We suggest, as future measures of conservation, the regular monitoring of the species (every five years), the creation of additional protected caves, the limitation of several aggressive activities around the caves (e.g. decreasing pasture intensification) and in some cases the creation of fences in the entrance of the most important caves.
Arthropoda, extinction risk, cave-adapted species, islands, IUCN, troglobionts, Red List
Three archipelagos of Macaronesia (Azores, Madeira, Canaries) have unique arthropod cave biological diversity (
The currently known diversity of Azorean troglobiont arthropods is composed of 17 described species and subspecies and four additional undescribed species (
After a previous assessment of the cave spider Turinyphia cavernicola (
To create the IUCN Red List profiles, we followed the standard procedures as in
Prior to the calculation of area of occupancy (AOO) and extent of occurrence (EOO), the 500 m x 500 m cells obtained from Azorean Biodiversity Portal were filtered to consider only the cells with high level of precision as defined by: 1 – very precise location, usually point UTM data; 2 – literature location not exceeding 25 km2. The centroid for each cell was calculated to obtain the distribution points for each species. The calculation of AOO and EOO was performed using the Geospatial Conservation Assessment Tool (GeoCAT) and using an approximation to the standard IUCN 2 km × 2 km cells (4 km2). Final maps with species distributions were produced using the IUCN standards with Google Earth (kmz files).
Critical information on species threats and conservation were mostly obtained from
Kingdom | Phylum | Class | Order | Family |
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Animalia | Arthropoda | Arachnida | Pseudoscorpion | Syarinidae |
Dinarte Teixeira
Axel Hochkirch
Suppl. material
The extent of occurrence (EOO) is 4 km² and the maximum estimated area of occupancy (AOO) is 4 km².
Pseudoblothrus oromii (Fig.
No decrease in EOO has been registered, but it is inferred from decline due to the vulnerability of its habitat, associated with the degradation of volcanic caves and anthropogenic impact in the surrounding area. Indeed, the cave Gruta da Beira is suffering from the important impact of dairy cattle management and pollution, and, because the cave is very accessible to visitation, the recreational cave visitation can have some impacts which have still not been measured.
No decrease in AOO has been registered, but it is inferred from decline due to the vulnerability of its habitat, associated with the degradation of volcanic caves and anthropogenic impact in the surrounding area (see details above in EOO).
Pseudoblothrus oromii occurs in a single cave, the cave of Gruta da Beira on the island of S. Jorge (Azores, Portugal), that is under intense disturbance (see threats below).
The species is historically only known from a single location.
The area surrounding the cave is heavily impacted by human disturbance.
The species is rare and only known from a single subpopulation in S. Jorge island.
The area surrounding the cave is heavily impacted by human disturbance.
Specimens were found near the entrance of the cave, under rotting wood and other organic litter.
Gruta da Beira is a 200 m long lava tube opening on a slope near an urbanised area. The surrounding area is highly disturbed by agricultural fields, mostly intensive pasture. The recent increase in tourism in Azores is creating opportunities to more organised visits to this cave that, due to its small size, could be highly impacted by recreational activities.
The genus Pseudoblothrus is exclusively cave-dwelling (
The main current threats to this species are the loss of habitat quality due to the impact of agriculture activities, agricultural and domestic pollution and recreational cave visitation. However, there are several future potential threats: climate changes in many habitats in Azores (see
Although the species is protected by regional law (
The species is not utilised.
Insufficient information available.
Further research is needed into its population, ecology and life history. It is necessary to establish a monitoring plan for the invertebrate community in the habitat in order to contribute to the conservation of this species.
Kingdom | Phylum | Class | Order | Family |
---|---|---|---|---|
Animalia | Arthropoda | Arachnida | Pseudoscorpion | Syarinidae |
Dinarte Teixeira
Axel Hochkirch
Suppl. material
The extent of occurrence (EOO) is 1525 km² and the maximum estimated area of occupancy (AOO) is 20 km².
Pseudoblothrus vulcanus is an endemic cave-adapted pseudoscorpion species known from Pico and Terceira islands (Azores, Portugal) (
No decrease in EOO has been registered but it is inferred from decline due to the vulnerability of its habitat, associated with the degradation of volcanic caves and anthropogenic impact in the surrounding area. In Furna do Frei Matias, Gruta das Agulhas and Gruta dos Principiantes, there is a current impact due to cave visitation. In almost of all the caves, agricultural activities and livestock raising, agricultural and domestic pollution are major problems for the underground environment.
No decrease in AOO has been registered, but it is inferred from decline due to the vulnerability of its habitat, associated with the degradation of volcanic caves and anthropogenic impact in the surrounding area (see details above).
This species occurs in eight volcanic caves in Pico (Furna da Baliza, Furna do Frei Matias and Furna Nova) and Terceira (Gruta das Agulhas, Gruta do Coelho, Gruta da Malha, Gruta dos Principiantes and Gruta de Santa Maria) islands that are under several threats, namely: agricultural activities and livestock raising, agricultural and domestic pollution and recreational cave visitation. Additionally, invasive plant species, altering the habitat at the entrance of the caves, might also impact the overall habitat quality in the caves.
Those 8 volcanic caves in Pico and Terceira islands are located in an area heavily impacted by agricultural activities and livestock raising, agricultural and domestic pollution, as well as by recreational cave visitation. Additionally, invasive plant species, altering the habitat at the entrance of the caves, might also impact the overall habitat quality in the caves. Possibly, the species occurred in more caves that have now been destroyed due to agriculture, road and urban development.
Due to ongoing impacts on the caves, the impact of human activities decreases the quality of cave environment.
This species is apparently quite common, occurring in eight volcanic caves. However, the threats described below are believed to be leading to a decrease in population numbers.
The areas surrounding the caves ar heavily impacted by human disturbance.
The species occurs in eight lava tubes, some in protected areas (Natural parks of Pico and Terceira), others are surrounded by highly disturbed or urbanised areas and two being coastal caves.
There is limited information regarding this species ecology and life-history. The genus Pseudoblothrus is exclusively cave-dwelling (
The main current threats to this species are the loss of habitat quality due to the impact of agricultural activities and livestock raising, agricultural and domestic pollution and recreational cave visitation. Additionally, invasive plant species, altering the habitat at the entrance of the caves, might also impact the overall habitat quality in the caves. However, there are several future potential threats: climatic changes will impact many habitats in Azores (see
The species is protected by regional law (
Insufficient information available.
Further research is needed into its population, ecology and life history. The fact that the species is a cave-adapted species and occurs in two islands may imply that we are in the presence of two cryptic species. Therefore, there is the urgent need of a taxonomic revision of this taxon.
Kingdom | Phylum | Class | Order | Family |
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Animalia | Arthropoda | Arachnida | Araneae | Theridiidae |
Sérgio Henriques
Axel Hochkirch
Suppl. material
The extent of occurrence (EOO) is ca. 275 km2 and the maximum estimated area of occupancy (AOO) is 28 km2.
Rugathodes pico is a cave-adapted endemic species known from Pico and Faial (Azores, Portugal) (
The species is a specialised troglobite living in constant humidity conditions. Many caves in Faial and Pico Islands are being impacted by pollution due to intensive cattle production, with changes in ecological conditions of caves in the last 50 years, namely, the change of the N and P abiotic cycles and changes in the water pH (
In Faial and Pico Islands, there are 19 well-surveyed caves and we found subpopulations in only seven. The trend of decline is partly based on the assumption that this species can occur in all these caves and that the absence is due not only to biological reasons (type of cave; age of the lava flow), but mainly to anthropogenic disturbance on caves during the last 50 years. Indeed, there is a strong predominance of intensive pastures and maize in areas theoretically unsuitable for this purpose in many Azorean islands, with the expansion between 2001 and 2011 of pasture intensification to areas more suitable to forest (
Six out of the seven volcanic caves (Gruta da Agostinha, Furna dos Montanheiros, Gruta das Canárias, Gruta do Henrique Maciel, Gruta do Mistério da Silveira I, Gruta do Soldão) (
After a detailed survey of 19 caves in Faial and Pico islands that include most of the range of the species, the species was only found at seven, which is a small number of caves for a predictably larger range (up to 5 times larger) just 50 years ago.
Each cave where the species occurs is affected by different threats, mainly touristic pressure, wine and cattle production with consequent deforestation and nutrient input into caves.
Seven subpopulations of this species can be found across two islands, but most of them are very small and located in disturbed lava tubes. The single large subpopulation is located in Gruta da Agostinha, which is under future threat due to increasing possibility of land-use changes for wine production.
Most of the subpopulations are living in volcanic caves surrounded by agricultural activities and/or domestic pollution and we suspect that the species has disappeared from other caves in the region.
The species is a troglobite specialist, occurring only in humid lava tubes and volcanic pits. In the cave with the larger subpopulation (Gruta da Agostinha), the species occurs in all sections of the cave.
The intensive cattle production in the islands of Faial and Pico has increased considerably in the last twenty years and creates high disturbance and pollution in the cave systems. Touristic pressure and land-use changes to wine production might also be a threat, through reduction in habitat quality.
T. pico adaptations related to cave life are the very pale colour, the long spines and hairs and the extreme length of the legs (
The main current threat to this species is the impact of agricultural activities, namely the expansion of wine production and domestic pollution. However, there are several future potential threats: climatic changes will impact many habitats in the Azores (see
The species is not protected by regional law. Some of the caves are included in the Natural Park of Faial and Pico. Since land-use changes (for Pittosporum undulatum removal, urban development, wine production) is the main current and future 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. The addition of fences around the caves will be an important mitigation measure.
The species is not utilised.
Further research is needed into its ecology and life history in order to find extant specimens in additional caves. An area-based management plan is necessary for the most disturbed caves including invertebrate monitoring to contribute to a potential species recovery plan.
Kingdom | Phylum | Class | Order | Family |
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Animalia | Arthropoda | Malacostraca | Amphipoda | Talitridae |
Dinarte Teixeira
Axel Hochkirch
Suppl. material
The extent of occurrence (EOO) is 4 km² and the maximum estimated area of occupancy (AOO) is 4 km².
Macarorchestia martini is possibly an endemic cave-adapted species known from a single island, Terceira (Azores, Portugal) (
The species is occurring in a single cave, the coastal lava tube of Gruta das Agulhas, Terceira (Azores, Portugal). No decrease in EOO has been registered but it is inferred from decline due to the vulnerability of its habitat, associated with the degradation of volcanic caves and anthropogenic impact in the surrounding area (e.g. agriculture pollution).
This species occurs only in a cave of Terceira island (Gruta das Agulhas) and it is not known if it ever occurred outside it. No decrease in AOO was observed, but it is inferred from decline in habitat quality associated with the degradation of volcanic caves and anthropogenic impact in the surrounding area (e.g. agriculture pollution).
The species is only known on a single island, Terceira (Azores, Portugal) (
The species is only present in one single cave. Stable despite the impending threats.
The area surrounding the cave is heavily impacted by human disturbance and decreases the quality of the cave environment.
The species is rare and only known from a single subpopulation in Terceira island. The area surrounding the cave is heavily impacted by human disturbance.
Only one subpopulation historically known.
The species occurs naturally in a single cave.
Specimens were found at some distance from the entrance of Gruta das Agulhas (a 250 m long lava tube on the seashore, opening some 5 m above the sea level), but where dim light was still available, in high humidity but without permanent water.
The area surrounding the cave is heavily impacted by human disturbance; the aboveground area is disturbed by urbanisation and agricultural fields (pollution by herbicides and pesticides). The easy access to the cave leads to uncontrolled cave visitation with potential impacts on the quality of the ecosystem. Debris is frequently seen in the cave.
There is limited information regarding this species ecology and life history. This species has reduced eyes, but few other adaptations to cave life (
The main current threats to this species are the loss of habitat quality at the cave entrance due to the impact of agriculture activities, agricultural and domestic pollution and recreational cave visitation. However, there are several future potential threats: climatic changes (see
Although the species is protected by regional law (
The species is not utilised.
Insufficient information available.
Further research is needed into its ecology and life history in order to provide a species conservation plan and a management plan that would improve the survival chances of this species for the future. A species conservation plan and a management plan would improve its survival chances for the future. Additional surveys are needed to confirm the troglobiont status of this species (see e.g.
Cave dwelling springtail
Kingdom | Phylum | Class | Order | Family |
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Animalia | Arthropoda | Hexapoda | Collembola | Entomobryidae |
Dinarte Teixeira
Axel Hochkirch
Suppl. material
The extent of occurrence (EOO) is ca. 2828 km² and the maximum estimated area of occupancy (AOO) is 52 km².
Pseudosinella ashmoleorum is an endemic cave-dwelling springtail species known from Faial, Pico and Terceira islands (Azores, Portugal) (
The species occurs naturally in many caves and also in the MSS.
The species occurs naturally in many caves and also in the MSS.
The species occurs in several caves and lava tubes in Faial (Furna Ruim); in Pico (Gruta da Agostinha, Gruta do Henrique Maciel, Gruta do Soldão); in Terceira (Algar do Carvão, Gruta das Agulhas, Gruta dos Balcões, Gruta do Caldeira, Gruta do Coelho, Gruta do Chocolate, Gruta da Madre de Deus) that are under the impact of several important threats, namely: climatic changes in several important habitats in Azores (see
The species is known to be present in 11 caves in 3 different islands that are under the impact of several important threats. The possible additional locations were lost more than 10 years ago, meaning the current trend in number of locations is probably stable despite the impending threats.
The decline in number of individuals is inferred from the decline of habitat quality in many caves. Indeed, the high level of agriculture pollution is dramatically changing the cave ecosystems.
No current population size estimates exist for this species, but it seems to be relatively widespread through several caves and in the MSS of three islands. The areas surrounding the caves are heavily impacted by human disturbance, including nitrates pollution.
The decline in number of subpopulations is inferred from the decline of habitat quality in many caves.
There is limited information regarding this species ecology and life history. It occurs in eleven volcanic caves, some in protected areas (Natural Parks of Pico and Terceira) and some surrounded by disturbed habitats and also in the MSS (mesocavernous shallow stratum) habitats (
The quality of the habitat in most of the caves is decreasing due to the impact of several important threats, namely: agriculture pollution; change in the road and urban infrastructure around the caves; potential human recreational activities with disturbance caused by radical cave visitation; reforestation of the areas with exotic trees with unknown impact.
Pseudosinella ashmoleorum was found in the dark and humid part of caves, with abundant mud or roots from the ceiling (
The main current threats to this species are the loss of habitat quality due to human activities like agriculture pollution, urbanisation and construction and recreational cave visitation. However, there are several future potential threats: climatic changes will impact many habitats in the Azores (see
The species is not protected by regional law. Part of its habitat is in regionally protected areas (Natural Parks of Pico and Terceira). Land-use change is one of the main current and future threats and conservation and restoration measures should be extended beyond the caves. As a future measure of conservation, the restriction of visits to the caves could be considered. A habitat management plan is needed and is anticipated to be developed during the coming years.
The species is not utilised.
Insufficient information available.
Additional research is needed in order to determine the levels of population size, as well as its ecology and life history. It is also necessary to establish a monitoring plan for the invertebrate community in the habitat in order to contribute to the conservation of this species.
Cave planthopper
Kingdom | Phylum | Class | Order | Family |
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Animalia | Arthropoda | Insecta | Hemiptera Fulgoromorpha | Cixiidae |
Anja Danielczak
Axel Hochkirch
Suppl. material
The extent of occurrence (EOO) is 8 km2 and the maximum estimated area of occupancy (AOO) is 8 km2
Cixius cavazoricus is a single island endemic cave planthopper species restricted to Faial Island (Azores, Portugal) (
No decrease in EOO has been registered but it is inferred from decline in the habitat quality.
No decrease in AOO has been registered but it is inferred from decline in the habitat quality.
Two locations, Gruta das Anelares and Gruta do Cabeço do Canto, are threatened by above-cave deforestation which will reduce the amount of roots suitable as food resources. Increasing nitrogen levels derived from the use of pesticides in neighbouring agricultural land are also a threat since they change the necessary cover by native trees and shrubs above ground.
The current trend in number of locations is probably stable despite the impending threats.
The current threats are believed to cause a decrease in the species population numbers at unknown rates.
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 sampling efforts. The species was not found during a fieldwork survey in 2010 and only a single specimen was found in one of the caves in May 2014.
Only two subpopulations historically known. The species was not found during a fieldwork survey in 2010 and only a single specimen was found in one of the caves in May 2014.
This is a troglobitic species that only occurs in two lava tubes in Faial Island (Azores, Portugal) (
Habitat quality is decreasing due to 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 necessary cover by native trees and shrubs above ground.
The species is restricted to the deep dark cave zone (
Cixius cavazoricus is highly threatened by above-cave deforestation which reduces the food resources. Increasing pesticides in neighbouring agricultural land are also a threat. However, there are also several future potential threats: climatic changes will impact many habitats in the Azores (see
The species is protected by regional law (
Insufficient information available.
Further research is needed into its ecology and life history in order to find extant specimens in additional caves. A species conservation plan and a management plan would improve the survival chances of this species for the future.
Cave planthopper
Kingdom | Phylum | Class | Order | Family |
---|---|---|---|---|
Animalia | Arthropoda | Insecta | Hemiptera Fulgoromorpha | Cixiidae |
Anja Danielczak
Axel Hochkirch
Suppl. material
The extent of occurrence (EOO) is 140 km2 and the maximum estimated area of occupancy (AOO) is 40 km2
Cixius azopicavus is a single island endemic cave planthopper species from Pico Island (Azores, Portugal) (
No decrease in EOO has been registered but it is inferred from decline in the habitat quality.
No decrease in AOO has been registered but it is inferred from decline in the habitat quality, including deforestation above the lava tubes, decreasing the amount of roots available, increased nitrogen concentration from the use of pesticides in nearby pastures and increased dryness inside the caves.
Six locations, Furna dos Montanheiros, Gruta das Canárias, Gruta da Agostinha, Gruta do Mistério da Silveira I, Gruta do Soldão and Gruta das Torres, are threatened by above-cave deforestation which will reduce the amount of roots suitable as food resources. Increasing pesticide levels, derived from neighbouring agricultural land, are also a threat.
The current trend in number of locations is probably stable despite the impending threats.
The current threats are believed to cause a decrease in the species population numbers at unknown rates.
The species only occurs in six lava tubes (caves) in Pico Island (Azores) and is particularly rare in terms of abundance in all caves.
Only six subpopulations historically known and some are in danger of extinction. The recent trend in removing exotic and native trees and shrubs for wine fields can be a major threat.
This is a troglobitic species with low dispersal ability (
Threats to this species include deforestation above the lava tubes, decreasing the amount of roots available, increased pesticides in nearby pastures and increased dryness inside the caves.
This is a troglobitic species with low dispersal ability. It is known to feed on roots of the above-cave vegetation. It only occurs in six lava tubes in Pico Island, where it is restricted to the deep dark cave zone (
This species is threatened by above-cave deforestation which will reduce the amount of roots suitable as food resources. The recent trend in removing exotic and native trees and shrubs for wine fields can be a major threat. Increasing pesticides in neighbouring agricultural land are also a threat. However, there are also several future potential threats: climatic changes will impact many habitats in the Azores (see
This species is not protected by law in the Azores, but part of its distribution is included in protected areas namely in a protected landscape area (Furna dos Montanheiros inside de Pico Natural Park) and a natural monument (Gruta das Torres). Degraded habitats should be restored and a strategy needs to be developed to address the future threat by climate change that may change the vegetation cover of caves. A habitat management plan with associated education outreach initiatives is needed and anticipated to be developed during the coming years. It is necessary to establish a monitoring plan for the invertebrate community in the habitat in order to contribute to the conservation of this species.
Species not utilised
Insufficient information available.
Further research is needed into its ecology and life history in order to find extant specimens in additional caves. A species conservation plan and a management plan would improve the survival chances of this species for the future.
Cave ground beetle (English); Carocho cavernícola (Portuguese)
Kingdom | Phylum | Class | Order | Family |
---|---|---|---|---|
Animalia | Arthropoda | Insecta | Coleoptera | Carabidae |
Anja Danielczak
Axel Hochkirch
Suppl. material
The extent of occurrence (EOO) is 8 km2 and the maximum estimated area of occupancy (AOO) is 8 km2
Thalassophilus azoricus is an endemic species from a single island, S. Miguel (Azores, Portugal) (
This species occurs only in a single lava-tube cave in S. Miguel Island (Gruta de Água de Pau) (
This species occurs only in single cave in S. Miguel island (Gruta de Água de Pau). The value of AOO given is an overestimation given that the AOO value is based on cave spatial occupancy, but the species in question might be restricted to a smaller area within the lava tube.
This species occurs only in single cave of S. Miguel island (Gruta de Água de Pau), that is under several threats, namely: i) residential and commercial development in coastal areas; ii) cave visitation by tourists and coastal recreational activities; iii) agriculture activities with cattle pollution; iv) creation of roads or coastal tracks; v) domestic water management.
Only naturally present in a single location. Several caves in this island have been sampled for cave fauna (
The species is very rare and only known from a single population. A continuing decline in the number of mature individuals is inferred from the ongoing cave habitat degradation due to pasture cattle pollution and pollution resulting from fertiliser use.
Occurs naturally in a single cave under current and potential future threats, that include tourist visitation, cattle pollution and climate change. This is believed to be leading to a decrease in population numbers.
Only one subpopulation historically known.
This species occurs in a volcanic cave (a lava tube only 15 m above the sea level and covered by some 70 m of overburden) in the S. Miguel island (Gruta de Água de Pau) (
The habitat is under several current and future threats (visitation, cattle pollution and Climate Change) (see more details below).
This is a troglobiont species with considerable eye reduction, depigmentation and appendage elongation (
The main threats to this species are: i) residential and commercial development in coastal areas; ii) cave visitation by tourists and coastal recreational activities, promoting disturbance; iii) agriculture activities with cattle pollution; iv) creation of roads or coastal tracks; v) domestic water management; and vi) future climatic changes are expected to have impacts on coastal habitats (
The species is protected by regional law (
Species not utilised
Insufficient Information Available
Additional research is needed in order to determine the levels of population size as well as its ecology and life history. It is also necessary to establish a monitoring plan for the invertebrate community in the habitat in order to contribute to the conservation of this species.
Cave ground-beetle (English); Carocho cavernícola (Portuguese)
Kingdom | Phylum | Class | Order | Family |
---|---|---|---|---|
Animalia | Arthropoda | Insecta | Coleoptera | Carabidae |
Anja Danielczak
Axel Hochkirch
Suppl. material
The extent of occurrence (EOO) is 4 km2 and the maximum estimated area of occupancy (AOO) is 4 km2.
Trechus isabelae is a single island endemic cave-adapted species, restricted to S. Jorge (Azores, Portugal) (
This species occurs only in a cave of S. Jorge island (Algar do Morro Pelado). The value of EOO is an overestimation given that the EOO value is restricted to cave size.
This species occurs only in a cave of S. Jorge island (Algar do Morro Pelado). The value of AOO is an overestimation given that the AOO value is restricted to cave size.
This species occurs only in a cave of S. Jorge island (Algar do Morro Pelado) that, in spite of the fact that it has no current known threats, can be under future severe threats (see below).
The single location is the full known historical range. Several caves in this island have been sampled for cave fauna (
The species is very rare and only known from a single subpopulation. The number of individuals caught when the species was discovered was small when compared with other Trechus Azorean species more abundant in traps (e.g. T. terceiranus and T picoensis). The cave where the species occurs is located in a protected area and of difficult access and we assume there is no current impact for the population.
Only one subpopulation historically known.
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 (
The habitat is pristine and well preserved.
This is a cavernicolous (i.e. a troglobitic species) predator and/or saprophagous species. The known specimens were captured only in pitfall traps.
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 will impact many habitats in Azores (see
The species is protected by regional law (
The species is not utilised.
Insufficient information available.
Additional research is needed in order to determine the levels of population size as well as its ecology and life history. A monitoring plan is also necessary for the invertebrate community in the habitat in order to contribute to the conservation of this species.
Cave ground-beetle (English) ; Carocho cavernícola (Portuguese)
Kingdom | Phylum | Class | Order | Family |
---|---|---|---|---|
Animalia | Arthropoda | Insecta | Coleoptera | Carabidae |
Anja Danielczak
Axel Hochkirch
Suppl. material
The extent of occurrence (EOO) is 4 km2 and the maximum estimated area of occupancy (AOO) is 4 km2.
Trechus jorgensis is an endemic cave-adapted species known from a single island, S. Jorge (Azores, Portugal) (
This species occurs only in a cave of S. Jorge island (Algar das Bocas do Fogo). The species is threatened due to the loss of habitat quality, since the volcanic pit has been used as a dump site. In addition, there is ongoing destruction of the surrounding habitat due to the spread of invasive plants.
This species occurs only in a cave of S. Jorge island (Algar das Bocas do Fogo). The species is threatened due to the loss of habitat quality, since the volcanic pit has been used as a dump site. In addition, there is ongoing destruction of the surrounding habitat due to the spread of invasive plants.
This species occurs only in a cave of S. Jorge island (Algar das Bocas do Fogo), which is currently under serious threat.
The single location is the full known historical range.
The species is very rare and only known from a single subpopulation. In all the sampling occasions, only a small number of specimens were collected. The area surrounding the cave is heavily impacted by human activities and used as a dump area.
Only one subpopulation historically known.
This species occurs in a 50 m deep volcanic pit (Algar das Bocas do Fogo, S. Jorge island), whose internal vault is in penumbra (not complete darkness). The surrounding area consists of exotic plantations of Pittosporum undulatum (
The habitat is under severe destruction by being located in a dump area.
This is a cavernicolous (i.e. a troglobitic species) predator and/or saprophagous species. The known specimens were captured only in pitfall traps.
The main current threats to this species are the loss of habitat quality, as the volcanic pit has been used as a dump site, as well as the destruction of the surrounding habitat by invasive plants. However, there are several future potential threats: climatic changes will impact many habitats in Azores (see
Although the species is protected by regional law (
The species is not utilised.
Insufficient information available.
Additional research is needed in order to determine the levels of population size as well as its ecology and life history. A monitoring plan is also necessary for the invertebrate community in the habitat in order to contribute to the conservation of this species.
Cave ground-beetle (English); Carocho cavernícola (Portuguese)
Kingdom | Phylum | Class | Order | Family |
---|---|---|---|---|
Animalia | Arthropoda | Insecta | Coleoptera | Carabidae |
Anja Danielczak
Axel Hochkirch
Suppl. material
The extent of occurrence (EOO) is 12 km2 and the maximum estimated area of occupancy (AOO) is 12 km2.
Trechus montanheirorum is an endemic cave-adapted species known from Pico (Azores, Portugal) (
This species occurs in three caves of Pico island (Furna de Frei Matias, Furna dos Montanheiros and Gruta dos Vimes). No decrease in EOO has been registered, but it is inferred from decline in the habitat quality in two of the caves.
This species occurs in three caves of Pico island (Furna de Frei Matias, Furna dos Montanheiros and Gruta dos Vimes). No decrease in AOO has been registered, but it is inferred from decline in habitat quality in two of the caves.
This species occurs in three caves of Pico island (Furna de Frei Matias, Furna dos Montanheiros and Gruta dos Vimes). In one of the caves (Furna de Frei Matias), the species is threatened by uncontrolled visits and, in the other two, by dairy cattle pollution.
The current trend in number of locations is probably stable despite the impending threats.
The area surrounding one of the the caves (Furna dos Montanheiros) is relatively well protected, but the area surrounding the other two caves is more disturbed. Therefore, we assume relatively few impacts for the population but infer some decrease in density of individuals in at least two of the caves. However, tourism recreational activities could be a problem as well as agriculture management in two of the caves.
The species is relatively abundant in at least one of the caves (Furna dos Montanheiros). The area surrounding one of the caves (Furna dos Montanheiros) is relatively well protected, but the area surrounding the other two caves is more disturbed.
In at least two of the subpopulations, the threats are sufficient for placing the subpopulations at a risk of extinction (Furna do Frei Matias and Gruta dos Vimes).
This species occurs in three caves of Pico island (Furna de Frei Matias, Furna dos Montanheiros and Gruta dos Vimes). This species has some ability to colonise the entrances to the caves, but no specimens were ever collected outside a cave (
There is already some impact from touristic visitation in at least one of the caves (Furna Frei Matias).
This is a cavernicolous (i.e. a troglobitic species) predator and/or saprophagous species.
The main current threats to this species are the loss of habitat quality, due to recreational cave visitation and the impact of pasture lands. In one of the caves (Furna de Frei Matias), the species is threatened by uncontrolled visits and, in the other two, by dairy cattle pollution. However, there are several future potential threats: climatic changes will impact many habitats in the Azores (see
The species is protected by regional law (
The species is not utilised.
Insufficient information available
Additional research is needed in order to determine the levels of population size as well as its ecology and life history. It is also necessary to establish a monitoring plan for the invertebrate community in the habitat in order to contribute to the conservation of this species.
Cave ground-beetle (English); Carocho cavernícola (Portuguese)
Kingdom | Phylum | Class | Order | Family |
---|---|---|---|---|
Animalia | Arthropoda | Insecta | Coleoptera | Carabidae |
Anja Danielczak
Axel Hochkirch
Suppl. material
The extent of occurrence (EOO) is 4 km2 and the maximum estimated area of occupancy (AOO) is 4 km2.
Trechus oromii is a cave-adapted endemic species known from Faial (Azores, Portugal) (
This species occurs only in a cave of Faial island (Gruta do Parque do Capelo). No decrease in EOO has been registered, but it is inferred from decline in the habitat quality.
This species occurs only in a cave of Faial island (Gruta do Parque do Capelo). No decrease in AOO has been registered, but it is inferred from decline in the habitat quality.
This species occurs only in a cave of Faial island (Gruta do Parque do Capelo) that is threatened by the loss of habitat quality, due to recreational cave visitation and to the impact of the management of the Nature Reserve & Recreational Park, where the cave is located.
The single location is the full known historical range.
The area surrounding the cave is heavily impacted by human disturbance. The cave entrance is located in a forest recreational park with several kind of activities and it is frequent to see some uncontrolled cave visitation.
The species is very rare and only known from a single subpopulation in Faial island.
Only one subpopulation historically known.
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.
There is already some impact from construction and human activity in the Forest Park, where it is located. Unfortunately, some uncontrolled cave visitation is frequently seen. In addition, there was a recent reorganisation of the park with some trees removed and new buildings and trails created with unknown impacts on the cave.
This is a cavernicolous (i.e. a troglobitic species) predator and/or saprophagous species.
The main current threats to this species are the loss of habitat quality, due to recreational cave visitation and the impact of the management of the Nature Reserve & Recreational Park, where the cave is located. Unfortunately, some uncontrolled cave visitation is frequently seen. In addition, there was a recent reorganisation of the park with some trees removed and new buildings and trails created with unknown impacts on the cave. However, there are several future potential threats: climatic changes will impact many habitats in the Azores (see
The species is protected by regional law (
The species is not utilised.
Insufficient information available.
Additional research is needed in order to determine the levels of population size, as well as its ecology and life history. It is also necessary to establish a monitoring plan for the invertebrate community in the habitat in order to contribute to the conservation of this species.
Cave ground-beetle (English); Carocho cavernícola (Portuguese)
Kingdom | Phylum | Class | Order | Family |
---|---|---|---|---|
Animalia | Arthropoda | Insecta | Coleoptera | Carabidae |
Anja Danielczak
Axel Hochkirch
Suppl. material
The extent of occurrence (EOO) is 8 km2 and the maximum estimated area of occupancy (AOO) is 8 km2.
Trechus pereirai is an endemic cave-adapted species known from a single island, Pico (Azores, Portugal) (
The species occurs only in two lava-tube caves (Furna das Cabras II -200 m length; and Gruta da Ribeira do Fundo - 200 m length) on the island of Pico (Azores, Portugal). The value of EOO is an overestimation given that the EOO value is based on cave size and not on the actual area occupied by the species which might be smaller. No decrease in EOO has been registered but it is inferred from decline in the habitat quality.
The species occurs only in two lava-tube caves (Furna das Cabras II and Gruta da Ribeira do Fundo) on the island of Pico (Azores, Portugal). The value of AOO given is an overestimation given that the AOO value is based on cave size, but the species in question might be restricted to a smaller area within the lava tube. No decrease in AOO has been registered, but it is inferred from decline in the habitat quality.
The species occurs only in two lava-tube caves (Furna das Cabras II and Gruta da Ribeira do Fundo) on the island of Pico (Azores, Portugal) and which are currently under serious threat.
The current trend in number of locations is probably stable despite the impending threats.
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 recently; and the population in 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.
This is a very rare species and only known from two subpopulations in Pico island (
In at least one of the subpopulations, the threats are sufficient for placing the subpopulations at risk of extinction (Gruta da Ribeira do Fundo).
This species occurs in two small lave tubes located on Pico island (Gruta das Cabras II and Gruta da Ribeira do Fundo) (
Due to human activities involving garbage and solid waste dumping, as well as livestock farming, a loss of habitat quality is inferred.
Trechus pereirai is a cavernicolous (i.e. a troglobitic species) predator and/or saprophagous species.
This species is mainly threatened by human activities, especially garbage dumping and livestock farming affecting his habitat (Gruta da Ribeira do Fundo). However, there are several future potential threats: climatic changes will impact many habitats in the Azores (see
The species is protected by regional law (
The species is not utilised.
Insufficient information available.
Additional research is needed in order to determine the levels of population size as well as its ecology and life history. It is also necessary to establish a monitoring plan for the invertebrate community in the habitat in order to contribute to the conservation of this species.
Cave ground-beetle (English); Carocho cavernícola (Portuguese)
Kingdom | Phylum | Class | Order | Family |
---|---|---|---|---|
Animalia | Arthropoda | Insecta | Coleoptera | Carabidae |
Anja Danielczak
Axel Hochkirch
Suppl. material
The extent of occurrence (EOO) is 285 km2 and the maximum estimated area of occupancy (AOO) is 40 km2.
Trechus picoensis is a cave-adapted endemic species known from Pico (Azores, Portugal) (
It has a relatively small extent of occurrence (EOO = 285 km²) and the area surrounding some of the caves is heavily impacted by human activities, namely agriculture/livestock farming and unregulated visitation to some of the caves.
It has a reduced area of occupancy (AOO = 40 km²) and the area surrounding some of the caves is heavily impacted by human activities.
This species occurs in Pico island in nine lava-tubes (Furna da Baliza, Furna de Frei Matias, Furna das Cabras II, Furna dos Montanheiros, Furna Nova I, Gruta do Gabriel, Gruta do Henrique Maciel, Gruta da Ribeira do Fundo and Gruta das Torres) that are isolated in a sea of pastures and Cryptomeria japonica plantations and under several threats, namely the reduction of habitat quality.
Degradation of the habitat is observed due to human activities: agriculture/livestock farming and unregulated visitation to some of the caves.
The decreasing abundance of some subpopulations is inferred from the decrease in habitat quality and pollution derived from dairy cattle exploitation.
The species is particularly abundant in some of the caves in Pico island.
Some of the subpopulations are under intense threat due to pollution derived from dairy cattle exploitation.
This species occurs in several volcanic caves (lava-tubes) of Pico island. It shows a strong morphological adaptation to cave life (
The area surrounding some of the caves is heavily impacted by human activities: livestock farming/agriculture, timber production (Cryptomeria japonica) and by human intrusion and disturbance.
Trechus picoensis is a cavernicolous (i.e. a troglobitic species) predator and/or saprophagous species.
The main current threats to this species are the loss of habitat quality due to human activities: agriculture/livestock farming, forest logging and unregulated visitation to some of the caves. However, there are several future potential threats: climatic changes will impact many habitats in the Azores (see
The species is not protected by regional law. Some of the caves are in a regionally protected area (Natural Park of Pico). Degraded habitats should be restored, a strategy needs to be developed to address the future threat by climate change that may change the vegetation cover above the caves and the entrance to the caves, most impacted by unregulated human visitation, should be fenced. A habitat management plan is needed and is anticipated to be developed during the coming years.
This species is not utilised
Insufficient information available.
Additional research is needed in order to determine the levels of population size, as well as its ecology and life history. It is also necessary to establish a monitoring plan for the invertebrate community in the habitat in order to contribute to the conservation of this species.
Cave ground-beetle (English); Carocho cavernícola (Portuguese)
Kingdom | Phylum | Class | Order | Family |
---|---|---|---|---|
Animalia | Arthropoda | Insecta | Coleoptera | Carabidae |
Anja Danielczak
Axel Hochkirch
Suppl. material
The extent of occurrence (EOO) is 48 km² and the maximum estimated area of occupancy (AOO) is 44 km².
Trechus terceiranus is a widespread cave-adapted endemic species from Terceira (Azores, Portugal) (
It has an extent of occurrence (EOO) of 48 km² and the species is known from ten isolated subpopulations, but also occurs in "Milieu Souterrain Superficiel“ or ”Mesovoid Shallow Substratum" (MSS).
It has a reduced area of occupancy (AOO = 44 km²), but is common in many caves.
The species occurs in ten volcanic pits and/or lava-tubes (Algar do Carvão, Gruta da Achada, Gruta dos Balcões, Gruta do Caldeira, Gruta do Coelho, Gruta da Malha, Gruta do Natal, Gruta dos Principiantes, Gruta do Chocolate and Gruta de Santa Maria), that are under several potential threats.
The species is known from ten isolated abundant subpopulations, but the area surrounding some of the caves is not protected and we assume some possible future impacts for those isolated subpopulations. It is a widespread cave-adapted endemic species from Terceira (Azores, Portugal).
The species is particularly abundant in Terceira island.
The species is known from ten isolated abundant subpopulations, but the area surrounding some of the caves is not protected and we assume some possible future impacts for those isolated subpopulations.
This species occurs in several volcanic formations (lava tubes and volcanic pits) of Terceira island. This species is distributed by all hypogean environments of Terceira both in the cave and MSS - mesocavernous shallow stratum habitats (
The area surrounding some of the caves is heavily impacted by human activities and, in the Algar do Carvão Show-Cave, there is an ongoing impact from tourism visitation.
Trechus terceiranus is a cavernicolous (i.e. a troglobitic species) predator and/or saprophagous species. Based on monthly data collected from the Algar do Carvão show cave during ten years, we can confirm that this species is active all months of the year, but with a high density between May and September.
The main current threat to this species is cave visitation by tourists and the impact of agriculture activities. However, there are several future potential threats: climatic changes will impact many habitats in the Azores (see
The species is not protected by regional law. Part of its habitat is in a regionally protected area (Natural Park of Terceira). Degraded habitats should be restored and a strategy needs to be developed to address the future threat by climate change. A habitat management plan is needed and is anticipated to be developed during the coming years.
The species is not utilised.
Insufficient information available.
Further research is needed into its ecology and life history in order to find extant specimens. It is necessary to establish a monitoring plan for the invertebrate community in the habitat in order to contribute to the conservation of this species.
In this study, we have studied 15 Azorean endemic arthropods with some level of cave adaptation, grouping the historical data and giving new information about its distribution, habitat, threats and proposals for its conservation. Only three out of the 15 studied species are known from more than one island and the remaining are restricted to single islands. The three more widespread species are one Collembola, one pseudoscorpion and a spider and all of them may need some level of taxomic revision using molecular tools.
However, most of the Azorean cave arthropod species have a very restricted distribution, occupying a unique island and most of the times few caves and therefore they have a very small extent of occurrence (EOO) and area of occupancy (AOO). The lack of new records makes us consider the possibility that one of the species is extinct (Cixius cavazoricus). In fact, the two troglobitic species of the homopteran genus Cixius are under intense disturbance due to major land-use changes in epigean habitats above their known localities. In addition, many others species are in a critical conservation situation and actions should be taken with some urgency, namely the implementation of area-based management plans for the specifc caves.
Formal education and awareness is needed to allow future investments in cave protection that will create conflicts with farmers. The use of images from extreme macro can be a strategy to inform the public about the ecological an aesthetic value of Azorean endemic cave arthropods as was demonstrated by the recent urban outreach initiative at Angra do Heroísmo in Terceira Island (see
Many thanks to the project "Toyota Global Species Programme" that is supporting the IUCN SSC Mid-Atlantic Islands Specialist Group in performing the species conservation profiles of Azorean endemic arthropods. Open access was funded by Project AZORESBIOPORTAL – PORBIOTA (ACORES-01-0145-FEDER-000072). Data were derived from EU projects INTERREGIII B ATLÂNTICO (2004-2006), BIONATURA (2006-2008) and ATLANTISMAR - Mapping coastal and marine biodiversity of the Azores (Ref: M2.1.2/I/027/2011).
For the development of this paper the work of IRA, LLL and RN was partly supported, respectively, by grants FCT-SFRH/BPD/102804/2014, FCT - SFRH/BD/115022/2016 and FRCT-M3.1.2/F/035/2011.
Images taken by Enésima Mendonça and Javier Torrent are open access at AZORESBIOPORTAL led by PAVB. Many thanks to Pedro Oromí for the use of the image of Cixius azopicavus.
PAVB and PC conceived the project. PAVB conceived and drafted the manuscript. LL and RN collected the data. PAVB, LL, IA, CR, RN and MB performed species assessments. AD made the maps. SW and AH contributed with text. All the authors revised the final text.
Distribution of Macarorchestia martini in the Azores islands
Distribution of Pseudosinella ashmoleorum in Azores islands.
Distribution of Pseudoblothrus oromii in Azores islands.
Distribution of Pseudoblothrus vulcanus in Azores islands.
Distribution of Rugathodes pico in Azores islands.
Distribution of Cixius cavazoricus in Azores islands.
Distribution of Cixius azopicavus in Azores islands.
Distribution of Thalassophilus azoricus in Azores islands.
Distribution of Trechus isabelae in Azores.
Distribution of Trechus jorgensis in Azores
Distribution of Trechus montanheirorum in Azores.
Distribution of Trechus oromii in Azores.
Distribution of Trechus pereirai in Azores.
Distribution of Trechus picoensis in Azores.
Distribution of Trechus terceiranus in Azores.