The butterfly despite its wide Eurosiberian range is considered to be one of the most threatened European species, classified as vulnerable (VU) both in Europe and the European Union, and listed in Appendix II of the Bern Convention, as well as Appendix IV of the Habitats Directive (Van Swaay et al. This small butterfly (with a wing span of about 3 cm) inhabits clearings in wet, usually deciduous forests, and on wet meadows with scattered trees, as well as ecotones on the edges of forests and wet meadows or fens (Meyer ) suggest that microclimatic conditions are more important determinants of habitat quality than the presence of specific host plants.
The orthophotomap of the site in 2003 (b) is also presented so as to document the rapid changes in habitat composition, namely the spreading of forest.
Source of orthophotomaps: Digital Globe (acquired through Google Earth).
The aim of the present study was to fill this gap by investigating a highly isolated population of the species in Poland, where it is in decline and endangered by extinction (Sielezniew habitat were separated by narrow strips of forest, dominated by alders.
About 60% of the largest (0.45 ha) and the outermost west fragment was afforested about 3–4 years earlier, and it is currently covered by deciduous tree seedlings (mainly oaks and hornbeams). Surprisingly, indicate the three separate meadow fragments.
The seasonal population size was assessed at 168 adults, with a well balanced sex ratio.