The Bashkir Trans-Urals (the eastern part of the Republic of Bashkortostan) includes the low mountains and foothills of the eastern slope of the Southern Urals, as well as the adjacent Sakmaro-Tanalyk and Kizilo-Urtazym plains. The vegetation is forest-steppe and steppe. Despite the small amount of precipitation (350-450 mm/year), there are quite a lot of mires, especially in the northern part of the study area. Mires are located mainly on the slopes of mountains and hills and at their foothills, in endorheic basins, in river floodplains, and often have a large area (up to several hundred hectares). All mires are eutrophic, their vegetation cover includes paludified birch and black alder forests and treeless reed, reed-sedge, moss-sedge plant communities. In 2023, more than 240 mires were identified in the Bashkir Trans-Urals, 60% of the total area of which (more than 8 thousand hectares) were disturbed as a result of drainage and peat extraction. There are very few publications about the distribution and the state of populations of rare plant species in the mires of the study area. The aim of this work is to summarize and to analyze the data on the representation of rare species of vascular plants in the mires of the Bashkir Trans-Urals.

Currently, in the mires of the Bashkir Trans-Urals, 32 rare plant species in need of protection have been identified, including 25 species (Table 1) listed in core list of the Red Data Book of the Republic of Bashkortostan [Martynenko, 2021], as well as 7 species are included in the Appendix II to this book, i.e. “List of flora and fungi that require special attention to their condition in the natural environment and monitoring in the Republic of Bashkortostan” (Carex dioica, Ranunculus lingua, Salix myrtilloides, Salix pyrolifolia, Saussurea parviflora, Baeothryon pumilum, Utricularia intermedia). Two species (Liparis loeselii. and Orchis militaris) are included in the Red Data Book of the Russian Federation [Order ..., 2023].

The largest number of rare mire species belong to the families Orchidaceae (11 species) and Cyperaceae (4 species). About 80% of these rare species are stenotopic and have a fidelity score for the mire ecotope III-V. Therefore, the destruction or degradation of their habitats will lead to the disappearance of their local populations in the Bashkir Trans Urals.

Little is known about the population size of rare species growing in the mires of the Bashkir Trans-Urals. Local populations of these species are often small and usually consist of several dozen, rarely hundreds of individuals (Carex serotina, Dactylorhiza russowii, etc.). For few species, for instance, Orchis militaris, the subpopulation size within the mire can amount to several thousand individuals, but, depending on weather conditions, there are extreme fluctuations in the number of plants in different years. A decrease in the number or disappearance of subpopulations of rare plant species depends on different factors, i.e., fluctuations in the water level in lakeside mires, the habitat degradation along the edges of mires due to grazing and haymaking (Artemisia laciniata), drying out of mires due to a decrease in the groundwater level after droughts (Liparis loeselii, Saxifraga hirculus), drainage, peat extraction, peat fires and recreation.

Currently, populations of rare and protected species of vascular plants have been identified in 58 mires. The most valuable for the protection of rare species of vascular plants are the mire vegetation complexes of the natural monuments “Nurok Mire”, “Karpis Mire”, “Starobalbukovskoye Mire” [Muldashev et al., 2020]. Most of the mires of the Bashkir Trans-Urals, where habitats of rare species have been identified, do not have conservation status. Searching for new locations and monitoring local populations of rare plant species are a necessary for organizing effective protection of the biodiversity of this region, which is characterized by a high degree of agricultural development. Factors causing a reduction or disappearance of local populations of rare species in the mires of the Bashkir Trans-Urals are the consequences of drainage, fluctuations in the water level in lakeside mires, grazing and haymaking along the edges of mires, drought and recreation.