Countries of Occurrence:
Saint Helena - British Overseas Territory
Pryce, D. & White, L.
Facilitators / Compilers/s:
This species is currently known from eight locations, all but one of these being in areas with endemic vegetation such as 'Cabbage Tree' woodland (family Asteracea) and Tree Fern (Dicksonia arborescens L'Hér.) Thicket (Mendel, Ashmole and Ashmole 2008). In the 1960s it was found at two further locations away from endemic vegetation (Tsacas and Cogan 1977). The precise ecology of the species is unknown and there is a decline in the quality of endemic habitat across the range of the species due to the spread of alien invasive plant and animal species (e.g. Phormium tenax J.R. Forst. & G. Forst. and Formicidae). It has an extent of occurrence (EOO) of 24 km2 and an area of occupancy (AOO) of 20 km2. Therefore, it is assessed as Vulnerable
Endemic to the island of St Helena where it is restricted to the ‘Green Heartland’ of the island (Tsacas and Cogan 1977; Mendel, Ashmole and Ashmole 2008).
As an endemic species that has been found most often in areas of endemic vegetation, it is likely to have a preference for endemic plants as a food source, although there is currently no specific evidence for this. The quality of endemic habitat across its range is currently declining through invasion by alien plant species (e.g. Phormium tenax J.R. Forst. & G. Forst). There is also increasing pressure from invasive non-native predatory animal species (e.g. Formicidae); it is therefore inferred that the species is declining
This species seems to have a preference for woodland habitat where it is likely to be a stem or leaf miner in an unknown range of species; it probably has a preference for endemic or indigenous plants which are present at the majority of sites where it has been found. It appears to have a preference for damper areas and could therefore be vulnerable to drought.
There has been a general decline in the quality of endemic plant habitat that is present at most of the sites where this species has been found; there has also been an increase in the number of invasive non-native predators (e.g. Formicidae) across all habitats. Global warming is also a potential threat to habitat quality as this appears to be a species that prefers damper areas.
Determining the precise ecology of this species should be considered a priority as until this is known there is little that can be done to conserve it; indeed any research and monitoring of this species would be of value.