MAIISG

Assessment Rationale:

Encarsia estrellae is an endemic species of the Azores (Azores, Portugal), present on at least S. Miguel and Pico islands. This species is present in areas of native and exotic vegetation, but some areas are now highly disturbed. From the current data available, this species has a limited Extent of Occurrence (1,776 km2) and small Area of Occupancy (68 km2). There is a continuing decline in the extent and quality of habitat as a result of the invasion of non-native plants and of human activity. There is little information regarding its population, distribution and threats, and limited information regarding ecology and life history (Manzari et al., 2002). Therefore, we suggest as future measures of conservation: (1) regular monitoring of the species; and (2) control of invasive plant species. Based upon the known distribution and ecology, its small geographic range and the continuing decline of its habitat area and quality, this species is assessed as Endangered (EN).

Geographic Range:

Encarsia estrellae is an Azorean-endemic aphelinid wasp that occurs in São Miguel and Pico (Borges et al. 2010). It does occur in one Natural Forest Reserve on each island: Pico da Vara (Tronqueira) in S. Miguel and from Lagoa do Caiado in Pico. The Extent of Occurrence (EOO) is ca 1,776 km² and the Area of Occupancy (AOO) is 68 km².

Population:

No current population size estimates exist for this species.

Habitat and Ecology

The ecology and traits of this species are mostly unknown. Apheinidae are mainly endoparasitoids, ectoparasitoids or hyperparasitoids of Aleyrodoidea, Aphidoidea, Auchenorrhyncha, Psylloidea and Coccoidea, but also of the eggs of Lepidoptera and Orthoptera and of the eggs, larvae and pupae of Diptera (Goulet and Huber 1993). Encarsia species are mainly parasitoids of Sternorrhyncha, particularly of the Aleyrodidae and Diaspidae. Most have heteronomous life histories with females acting as primary parasitoids and males developing as hyperparasitoids on the same or different species (Hunter and Woolley 2001). Encarsia estrellae specimens have been reared from Aleyrodes singularis, Bemisia sp. and from other unidentified host species (Manzari et al. 2002). Specimens of this species have been collected in areas of native and exotic vegetation, but also in areas becoming highly disturbed.

Major Threat(s):

A lack of complete information regarding the distribution and population status of this species precludes a full assessment of potential threats. Nevertheless, the presence of this species in some areas highly disturbed by human presence, where major historical land use changes took place (Lagoa das Sete Cidades), or where there is an ongoing destruction of the native forest by the spread of invasive plants that are changing the habitat structure and promoting the spread of other exotic species (Tronqueira), might imply that this species is being affected by habitat degradation. Based on Ferreira et al. (2016), habitat declines as a consequence of climate change might also affect this species.

Conservation Actions

The species is not protected by regional law, but it has been collected in some regionally protected areas (Natural Parks of São Miguel and Pico). The São Miguel Natural Park administration is currently starting control measures of the invasive plants. A LIFE PRIOLO project started with a restoration of degraded habitats, increasing the area of pristine forest. A habitat management plan is needed and one is anticipated to be developed during the coming years. Degraded habitats could also be restored in Lagoa das Sete Cidades. A strategy also needs to be developed to address the future threat from climate change; while further research is needed into this species population, distribution, threats, ecology and life history.