Assessment Rationale:

Heteroderes azoricus is an endemic species present in Flores, Faial, Graciosa, Terceira, S. Miguel and Sta. Maria islands (Azores, Portugal). It has a large extent of occurrence (EOO = ca 39,000  km²) and a relatively small area of occupancy (AOO = 200 km²). The species is common and  known from at least 35 fragmented subpopulations in six islands. In the past, the species has probably strongly declined due to changes in habitat size and quality. The main threats to this species are currently agriculture activities, Cryptomeria japonica plantations management as well as invasive plants that are promoting dramatic changes in the low altitude habitats. Based upon the small area of occupancy and a continuing decline in EOO, AOO, habitat quality it is assessed as Endangered.

Geographic Range:

Heteroderes azoricus is an endemic species present in Flores, Faial, Graciosa, Terceira, S. Miguel and Sta. Maria islands (Azores, Portugal) (Borges et al. 2010), known from the Natural Forest Reserve of Pico Alto in Santa Maria. The extent of occurrence (EOO) is ca 39,000 km² and the maximum estimated area of occupancy (AOO) is 200 km².

Population:

H. azoricus is a widespread and particularly abundant species in several habitats. A decline in the population abundance is inferred as a consequence of the spread invasive plant species, exotic forest cut, intensive pasture management and urban development. This species is assessed here as severely fragmented as at least 50% of its population can be found in subpopulations that are 1) smaller than would be required to support a viable population, and 2) separated from other habitat patches by a large distance.

Habitat and Ecology

The species occurs in several habitats, like native forests, exotic forests, lava formations, grasslands and in agricultural land-uses of the Flores, Faial, Graciosa, Terceira, S. Miguel and Sta. Maria islands (Azores). It is widespread by the low altitude habitats in the archipelago (altitudinal range between 0 and 300 m). Adults and larvae are herbivores and feed on plant tissues. It is common to find many individuals under the bark of exotic trees.

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). Currently agriculture activities, Cryptomeria japonica plantations management as well as invasive plants are promoting dramatic changes in the low altitude habitats. Based on Ferreira et al. (2016) the habitat will further decline as a consequence of climate changes (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). In the remaining islands the species range is outside protected areas. 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. Further research is needed into its ecology and life history in order to find extant specimens in historical sites and in additional low elevation sites and obtain information on population size, distribution and trends. It is also necessary a monitoring plan for the invertebrate community in the habitat in order to contribute to perform a species potential recovery plan. A monitoring every ten years using the BALA protocol will inform about habitat quality (see e.g. Gaspar et al. 2011).