When south goes north: Mediterranean dragonflies (Odonata) conquer Flanders (North-Belgium)

摘要

Since 1980, eight southern dragonfly species have been regularly recorded in Flanders. They show a significant increase in relative abundance, relative area as well as indications of reproduction since the beginning of the nineties, with peak occurrence mainly in the 1995–1999 period. Since 2000, numbers are lower but more species were simultaneously present. Three species, Lestes barbarus, Crocothemis erythraea and Sympetrum fonscolombii, show a combination of earlier arrival, earlier reproduction with a higher frequency and higher maximum ranges and can be considered asstable populations in Flanders. All other southern species show in general a later arrival, only one confirmed or probable reproduction and have much lower maximum ranges. Two other species, reaching their northern limit of distribution in Flanders, Erythromma viridulum and E. lindenii have clearly expanded their relative area since the eighties. Their relative abundance also increased although this shows more fluctuations.