MAIISG

Assessment Rationale:

Chrysotus polychaetus is an endemic species of the Azores (Portugal), being present in Flores, Pico, S. Jorge and Terceira islands. This species has been described as apparently common and widespread through a wide variety of natural and disturbed habitats in the aforementioned islands (Frey 1945). From the historical data, this species potentially has a fairly small Extent of Occurrence (11,957 km2) and a limited Area of Occupancy (80 km2); and it is possible that this species has declined in the past as a result of human activity. The present situation of this species needs to be further assessed, and further research is needed into its population, distribution, threats, ecology and life history. However, despite the incomplete knowledge regarding this species' population, distribution, threats and ecology, this species is unlikely to warrant listing under the most threatened Red List categories. Pending further information, the number of locations could be said to be relatively small, and so the species can be precautionarily assessed as Near Threatened. Conservation of native forests and vegetation, native wet and boggy areas and natural streams and other water bodies could potentially aid this species' conservation.

Geographic Range:

Chrysotus polychaetus is an Azorean-endemic species that was described from the islands of Flores, Pico, S. Jorge, and Terceira (Azores, Portugal) (Borges et al. 2010), known from a wide variety of habitats. Based on the historical data (Frey 1945), the Extent of Occurrence (EOO) would be ca. 11,957 km² and the Area of Occupancy (AOO) would be ca. 80 km².

Population:

No current population size estimates exist for this species. Current Population Trend: Unknown. 

Habitat and Ecology

The ecology and traits of this species are unknown. Adults and most larvae of other species of Dolichopodidae are predators, feeding on other arthropods, with the adults of some species being notable predators of Culicidae (McAlpine et al. 1987). The larvae occupy a wide range of habitats, living generally in moist environments such as soil, moist sand, or rotting organic matter. The larvae pupate in cocoons made of cemented soil particles. Dolichopodidae in general inhabit lightly shaded areas near swamps and streams, or in meadows and woodlands (McAlpine et al. 1987). Other species of the genus Chrysotus are generally heliophilous, being found mainly on the foliage of low herbs, while a number of species seem to prefer wet, sandy banks of ponds and rivers. Chrysotus polychaetus has been found in a wide variety of habitats, mainly in native, deciduous and production forests (Cryptomeria japonica), heathland, and near lakes. Systems: Terrestrial.

Major Threat(s):

A lack of information regarding the present status of this species, precludes an assessment of potential threats. Nevertheless, the ecology of other members of the Dolichopodidae family suggests that this species might be affected by future habitat declines as a consequence of climate change (Ferreira et al. 2016) and increased droughts. Human disturbance and land use changes might have also affected this species.

Conservation Actions

The species is not protected by regional law. The present situation of this species needs to be further assessed, and further research is needed into its population, distribution, threats, ecology and life history. From what is known of its habitat preferences, conservation of native forests, native wet and boggy areas, natural streams and other water bodies could potentially aid this species' conservation. Historically at least, this species was present in areas that are currently included in the Natural Parks of Flores and Pico.