Rare, protected, and understudied vascular plant species of the pinewood complex of the Mozh River valley (Kharkiv Region, Ukraine)

The composition of the biota is dynamic and changes for many reasons, making biodiversity research relevant. Studies of rare species that are most vulnerable to anthropogenic pressures are of particular importance. Although the Mozh River flows through the central part of the Kharkiv Region, its valley remains understudied, especially the pine forests and their rare plants. The results of the current study include data from our field research, revision of the Herbarium of V.N. Karazin Kharkiv National University (CWU), and literature sources from the second half of the 20th century to the present. This paper contains an annotated list of 35 species of vascular plants. Each species is provided with the data on its geographical range, distribution in Ukraine, population status and its study history in the Kharkiv Region, conservation status, and the state of its population in the studied forests. We found the localities of two species included in Appendix I of the Bern Convention (Salvinia natans (L.) All. and Jurinea cyanoides (L.) Rchb. and six species included in the Red Data Book of Ukraine (Botrychium lunaria (L.) Sw., Pulsatilla pratensis (L.) Mill., Iris pineticola Klok., Neottia nidus-avis (L.) Rich., Neottia ovata (L.) Hartm., Tulipa quercetorum Klok. & Zoz). We also found 19 species rare in the Kharkiv Region (Lycopodium clavatum L., Athyrium filix-femina (L.) Roth, Ophioglossum vulgatum L., Campanula persicifolia L., Chimaphila umbellata (L.) W.P.C. Barton, Comarum palustre L., Hottonia palustris L., Rubus saxatilis L., Carex pseudocyperus L., etc.). Nine regionally rare plant species have the boreal range type; they occur at the southern limit of their distribution range which indicates the specificity of ecological and climatic conditions formed in the pine forests in the Mozh River valley. In addition, we found five species without conservation status, but they are rare in the region (Caltha palustris L., Catolobus pendulus (L.) Al-Shehbaz, Gratiola officinalis L., Lythrum hyssopifolia L., Rubus polonicus Barr. ex Weston), and, therefore, they are recommended to be included in the next edition of the Official List of the Regionally Rare Plants of the Kharkiv Region. Three species (Buglossoides czernjajevii (Klokov & Des.-Shost.) Czerep., Jacobaea andrzejowskyi (Tzvelev) B.Nord. & Greuter, Sedum album L.) were identified as understudied in the Kharkiv region due to the lack of or insufficient information on their distribution in the study area.