Challenges to the conservation of threatened species in alkaline fens: Study of Bagno Bubnów PLB060001

The objective of the present study is to draw attention to the problem of protecting alkaline fens (EU habitat 7230) and related plant species. The distribution, habitat conditions and vegetation structure of the phytocoenoses in which protected species diagnostic of eutrophic low-sedge alkaline fens of the Caricion davallianae alliance occurred in the area of PLB060001 Bagno Bubnów were therefore described. The findings of the research conducted in the years 2021–2022 enabled the identification of factors that pose a threat to their occurrence. The following species were documented: Epipactis palustris (44 locations), Carex davalliana (25), Pedicularis sceptrum-carolinum (3), Pedicularis palustris (1), Pinguicula vulgaris subsp. bicolor (1), Tofieldia calyculata (1). The species under study exhibit a diverse ecological spectrum. They occurred in diverse phytocoenoses, usually in Molinion meadows or Scheuchzerio-Carcietea nigrae low-sedge alkaline fens and were predominantly recorded on eutrophic, organic or mineral-organic, neutral or alkaline soils. The C:N ratio ranging from 12.20 to 13.55 on average, with high calcium content, and high level of base saturation which indicates eutrophic soils with advanced mineralisation and humification of organic matter. An analysis of the syntaxonomic structure of the examined phytocoenoses and soil conditions has revealed a potential risk of habitat loss due to drying out. The PCA revealed that moisture is a key element in maintaining protected species of alkaline fens and exerts a fundamental influence on the phytosociological variability of the investigated phytocoenoses of PLB060001 Bagno Bubnów site.