Habitat preferences of Hamatocaulis vernicosus at the junction of continental and boreal phytogeographical regions (Lithuania)

Based on the Nature Conservation Act, the rare fen moss Hamatocaulis vernicosus (Bern Convention, EU habitat directive) is protected in more than 500 Natura 2000 territories of Europe. Knowledge on its ecology is required to ensure favourable conservation status, meanwhile data from specific regions is still insufficient. The aim of this study was to highlight habitat characteristics specific at the junction of boreal and continental biogeographical regions. The data of 63 study plots included cover and abundance of the plant species, water parameters (conductivity, pH, and concentrations of Ca2+, Fe3+, K+, Mg2+, NH4+, NO3-, and PO43-), topography type and microrelief form. The specific features both in terms of water parameters and vegetation were ascertained. The habitats showed wide variation and high amounts of electrical conductivity, calcium, iron and magnesium. Most associated species were Carex diandra, C. rostrata, Menyanthes trifoliata, and Calliergonella cuspidata. The highest restriction with the most frequent plant communities showed Marchantia polymorpha, Plagiomnium ellipticum, and Rumex acetosa. Thus, the study confirms the general trends known for the habitat preferences of H. vernicosus and highlights the regionally based characteristics related to both water physical-chemical parameters and vegetation. To ensure favourable status of H. vernicosus throughout Europe, conservation measures that consider the particular features of the regional habitats should be applied.