MAIISG

Assessment Rationale:

Athous pomboi is a single island endemic species restricted to Sta. Maria (Azores, Portugal). It has a small extent of occurrence (EOO = 40  km²) and small area of occupancy (AOO = 40 km²). The species is very rare and  known from only a very small native forest fragment (0.09 km²) and some highly disturbed patches dominated by exotic plants. In the past, the species has probably strongly declined due to changes in habitat size and quality. The main current threats to this species are the spread of invasive plants, agriculture activities, Cryptomeria japonica pulp plantations management and habitat degradation in the unique site of native forest. 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). Based upon the small extent of occurrence and associated decline in extent of occurrence, area of occupancy and habitat quality it is assessed as Critically Endangered.

Geographic Range:

Athous pomboi is a single island endemic species restricted to Sta. Maria (Azores, Portugal) (Borges et al. 2010), known from Natural Forest Reserve of Pico Alto. The extent of occurrence (EOO) is 40 km² and the maximum estimated area of occupancy (AOO) is 40 km².

Population:

The species is very rare in all known locations in Sta. Maria island. A continuing decline in the number of mature individuals is inferred due to small patches and the expansion of invasive plants. This species is assessed here as severely fragmented as it is distributed in small isolated patches in Sta. Maria island. At least 50% of its population can be found in subpopulations/in habitat patches that are 1) smaller than would be required to support a viable population, and 2) separated from other habitat patches by a large distance. In fact, the species occurs in  natural forest fragments that are isolated in a sea of pastures and Cryptomeria japonica plantations. Most of the locations will be under severe threat in the next 10 years due to the aggressive spread of the invasive plants Hedychium gardnerianum and Pittosporum undulatum.

Habitat and Ecology

The species occurs in native forests, Cryptomeria japonica plantations and  Acacia spp. exotic forests in S. Maria (Azores), with a range between 100 and 550 m Asl. Adults and larvae are herbivores and feed on plant tissues, being active during the night. Adults are particularly active in summer.

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). One of the most important ongoing threats to this species is the spread of invasive plants (Hedychium gardnerianum), agriculture activities, Cryptomeria japonica pulp plantations management and habitat degradation in the unique site of native forest. 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. Its main native habitat is in a regionally protected area (Natural Park of Santa Maria). Further spread of invasive plants needs to be stopped in order to avoid any future declines of the species. 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 anticipated to be developed during the coming years. Further research is needed into its ecology and life history in order to find extant specimens in additional fragments of exotic forest in S. Maria and obtain information on population size, distribution and trends. It is also necessary an area-based management plan and a monitoring plan for the invertebrate community in the habitat in order to contribute to perform a species potential recovery plan. Monitoring every ten years using the BALA protocol will inform about habitat quality (see e.g. Gaspar et al. 2011).