MAIISG

Assessment Rationale:

Limnephilus atlanticus in an endemic caddisfly species present in six islands of the Azorean archipelago (Faial, Flores, Pico, Terceira, São Jorge and São Miguel) (Borges et al. 2010), being known from eleven Natural Forest Reserves of the islands. It has a large extent of occurrence (EOO =  ca 19,000 km²) and a relatively small area of occupancy (AOO = 108 km²). The species is abundant and  known from at least 11 subpopulations. In the past, the species has probably strongly declined due to changes in habitat size and quality. Human activity, particularly the drainage of wetlands and the contamination of freshwater bodies with agricultural runoff are also major threats to this species. The main current threat in forest floor is the spread of invasive species namely Hedychium gardenerianum. The main future threat to this species will be the habitat decline as a consequence of invasive species and climate change (increasing number of droughts) (Ferreira et al. 2016). The species is assessed as Near Threatened (NT), since the species has an AOO of 108 km² (i.e. < 2,000 km²), and there is a continuing decline in the number of locations.

Geographic Range:

Limnephilus atlanticus in an endemic caddisfly species present in six islands of the Azorean archipelago (Faial, Flores, Pico, Terceira, São Jorge and São Miguel) (Borges et al. 2010). Within these six islands it is known from eleven Natural Forest Reserves:  Morro Alto e Pico da Sé (Flores); Caldeira do Faial (Faial); Mistério da Prainha and Caveiro (Pico); Topo (S. Jorge); Biscoito da Ferraria, Pico Galhardo, Caldeira Sta. Bárbara e Mistérios Negros and Terra Brava (Terceira); Graminhais and Pico da Vara (S. Miguel). The extent of occurrence (EOO) is ca 19,000 km² and the maximum estimated area of occupancy (AOO) is 108 km².

Population:

The species is widespread and relatively abundant, but limited to suitable pristine habitats. At least in some islands the species continues in decline due to native forest destruction and habitat fragmentation and wetland drainage.

Habitat and Ecology

The adults occur mainly in the native forest with twilight activity. They are generalist phytophagous. The larvae construct portable cases from plant and mineral materials. The larvae are aquatic, but are also found in the forest floor in small streams and puddles or in other hiper-humid conditions. The larvae act as active shredders, exhibiting the same basic patterns of food exploitation as its European counterparts (Balibrea et al. 2016). Based on seasonal data from SLAM traps obtained in several islands between 2012 and 2016, the adults are active all year, being most abundant in spring and summer (Borges et al. 2017).

Major Threat(s):

In the past, the species has probably strongly declined due to changes in habitat size and quality (Triantis et al. 2010, Terzopoulou et al. 2015). Based on Ferreira et al. (2016) the habitat will further decline as a consequence of climate change (increasing number of droughts). Human activity, particularly the drainage of wetlands and the contamination of freshwater bodies with agricultural runoff are also major threats to this species. The main current threat in forest floor is the spread of invasive species namely Hedychium gardenerianum.

Conservation Actions

The species is not protected by regional law. Its habitat is in regionally protected areas (Natural Parks of, Faial, Flores, Pico, S. Jorge, Terceira, S. Miguel). Degraded habitats should be restored and a strategy needs to be developed to address the current threat by invasive species and the future threat by climate change. Further research is needed into its ecology and life history in order to understand its dynamics, namely at larvae stage. 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. Monitoring every ten years using the BALA protocol will inform about habitat quality (see e.g. Gaspar et al. 2010).