Die Libellenfauna der Ostseeinseln Wollin (NW Polen) und Usedom (NO Deutschland) mit angrenzendem Festland – Frühjahrsaspekt 2018, und Anmerkungen zum Vorkommen von Coenagrion armatum (Charpentier, 1840)

In May 2018, 34 dragonfly species were recorded on Wolin (21), Usedom (30) and the adjacent mainland (21). The most frequent spring species in the area were Coenagrion puella, Libellula quadrimaculata, C. pulchellum, Ischnura elegans, Erythromma najas, Brachytron pratense and Cordulia aenea. C. lunulatum and Calopteryx virgo were recorded for the first time on Usedom, while Anax parthenope, Libellula fulva and Leucorrhinia caudalis were recorded for the first time on Wolin. The occurrence of Coenagrion armatum, which had been recorded in 2016 on Usedom, could not be confirmed. The quantitative results of the survey are given for different types of water bodies (ditches, pools, ponds, lakes, bog lakes). The average number of species per water body was highest in bog lakes (7.5) and lowest (3.4) in temporary pools. In comparison to older studies from the area, the flight season started 13.7 days earlier in 2018 than in years documented prior to 1989. This might be explained by climatic changes. The species composition, however, has remained rather stable – at least on Usedom and the mainland. On Wolin, climatic factors as well as habitat loss and transformation have led to a species composition that is different from the one recorded in the first half of the 1970s.