The semi-aquatic fly fauna (Diptera) of wetlands of the Åland Islands

Authors

• Olli Autio
• Jukka Salmela

Abstract

Semiaquatic flies (Diptera, Nematocera: Limoniidae, Tipulidae, Pediciidae, Cylindrotomidae, Ptychopteridae, Psychodidae and Dixidae) of wetlands in the Åland Islands were collected from 19 sites withMalaise traps. Sites included openmires, woodedmires, rich fens, Baltic shore meadows, ditches and a grove. A total of 104 species were found of which 58 were recorded for the first time from the Åland Islands. Baltic shore meadows were the most species rich habitat type with 44 species. They were followed by ditches (41 spp.). However, local nematoceran communities of the Åland Islands are on average composed of fewer species than in other parts of southern Finland. Also the known total number of species is lower in the region of Åland than in the other regions of southern Finland. The theory of island biogeography may partly explain this. Åland is situated about 40 km from the nearest continental area. However, the best explanation for the observed species numbermay be that the islands are lacking some of themost species-rich habitats, for example, brooks and springs.