A survey on the nematoceran (Diptera) communities of southern Finnish wetlands

Abstrakti

We examined the community composition and diversity of nematoceran flies (Diptera) in 14 wetland habitats (springs, mires, streams) located in southern Finland. Based on NMS ordination and Cluster analysis, groundwater influence and vegetation type discriminated the studied communities quite clearly. Atotal of 8,606 specimens belonging to 156 species were identified, distributed as follows: Limoniidae (80 species), Psychodidae (26), Tipulidae (20), Pediciidae (10), Dixidae (9), Cylindrotomidae (4), Ptychopteridae (4), Thaumaleidae (1), Pleciidae (1) and Pachyneuridae (1). The most species rich locality, Ruottaniitty rich fen in Ruovesi, harboured 69 species, while only 12 species were found from the least diverse locality; mean species richness of the studied sites was 40,3. Molophilus pullus (Limoniidae), Tinearia lativentris (Psychodidae) and Dixella nigra (Dixidae) are reported for the first time from Finland and the ecology and distribution of several rare and preliminary red-listed flies are discussed.We conclude that nematocerans have great potential as tools for bioassessment, conservation and monitoring of wetlands in the boreal region. We emphasize the importance of nearly pristine and species rich spring-fed fens in Ruovesi for the biodiversity preservation of Finnish wetlands.