Assessment Rationale:

Eudarcia atlantica is an endemic species present in Faial, Terceira and S. Miguel islands (Azores, Portugal) (Borges et al. 2010). It has a relatively small area of occupancy (AOO = 36 km²) and a large extent of occurrence (EOO = ca 7,600  km²). The species is widespread and often found on walls and rocks in the coastal habitats with green algae, which grow along with lichens on shaded rocks. Based on Ferreira et al. (2016) the habitat will decline as a consequence of climate change (increasing number of droughts). Based on its small AOO, small number of locations and a continuing decline in AOO and EOO this species is assessed as Endangered.

Geographic Range:

Eudarcia atlantica is an endemic species present in Faial, Terceira and S. Miguel islands (Azores, Portugal) (Borges et al. 2010), known from from costal rocks. Only known from one Natural Forest Reserve at Caldeira do Faial (Faial). The extent of occurrence (EOO) is ca 7,600 km² and the maximum estimated area of occupancy (AOO) is 36 km².

Population:

The species is widespread and often found on walls and rocks in the coastal habitats with green algae, which grow along with lichens on shaded rocks (Henderickx 1995). It presents a stable population.

Habitat and Ecology

Eudarcia atlantica occurs in three Azorean islands (Faial, Terceira and S. Miguel). The larvae live in a portable case that is covered with sand and soil particles, and feed on green algae which grow along with lichens on black lava rocks; larval cases are often found on walls and rocks in the coastal area (Henderickx 1995). Since only females were found, the possibility of parthenogenety was considered by Henderickx 1995. According to this author, larvae and pupae were collected in July, imagos were obtained in August-September. From larvae collected in April in S. Miguel adults emerged in May and June (O. Karsholt, unpubl.). Altitudinal range: 10-200 m.

Major Threat(s):

In the past, the species has probably declined due to changes in habitat size and quality, mostly the creation of pastures  (Triantis et al., 2010). Currently invasive plants Carpobrotus edulis and Hedychium gardnerianum are changing some of the areas and decreasing the quality of the habitat. These changes are decreasing the relative cover of endemic plants and changing the soil cover (decreasing the cover of bryophytes and ferns). Based on Ferreira et al. (2016) the habitat will further decline as a consequence of climate change (increasing number of droughts and habitat shifting & alteration).

Conservation Actions

The species is not protected by regional law. Further research is needed to monitor the species and conservation measures to control the invasive Hedychium gardnerianum and Carpobrotus edulis should be implemented to improve habitat quality for this species. Additional research is needed into its ecology and life history in order to find extant specimens. Degraded habitats should be restored and a strategy needs to be developed to address the future threat by climate change. 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.