# Impact of High Water Levels in Lake Baikal on Rare Plant Species in the Coastal Zone
## 3 Results and Discussion
The population density ranged from 8 to 30 individuals per 1 m\({}^{2}\). Therefore, the plants inhabiting shallow waters and subject to flooding at elevations above 457.10 m will be affected first. The main bulk of _C. subvillosum_, which is confined to the surf zone, is inundated at water levels from 457.70 m. High water levels combined with wind-wave activity will result in the destruction of its habitat. As an example, the monitoring site of the Transbaikal National Park established in 2015 for observations of _C. subvillosum_[45] has been subjected to erosion and is already half washed away by waves (Figure 5). Figure 5: _C. subvillosum_ monitoring site in the Transbaikal National Park. (**a**) Photo by MBU DO ”Podlemore”, 13 June 2019. (**b**) Photo by BINM SB RAS, Zharnikova M.A., 29 June 2023. C. ulopterum_ is not abundant in the study habitats. It is observed in small populations on sandy hillocks in the vicinity of Goryachinsk and Ust-Barguzin. The population density is 0.03 species per 1 m\({}^{2}\). It is estimated that a minimum of 30 species will be exposed to the inundation zone at a height above 457.60 m. The remaining species are projected to experience detrimental impacts due to the destruction of their habitats by autumn storms. The losses of rare species from inundation were defined under the condition of the static state of the water surface of the lake. However, exogenic relief-forming processes in the coastal zone resulting from an increase in water level lead to the disturbance of ecotopes. Thus, when the water level in the lake increases, shoreline erosion, a reduction in the length and areas of beaches, sand washout, and the erosion of spits in river mouths and bays, especially strongly manifested in the period of active wave activity or during storms, is inevitable. This aspect requires additional research. The cost estimation of damage from the rise of Lake Baikal's water level was carried out in accordance with the standards approved in standardized methods. The total cost damage is calculated by multiplying the tax rate (600 rubles) by the number of individuals lost. Damage to rare plant species listed in the Red Data Book of the Republic of Buryatia at high water levels of Lake Baikal is presented in Table 2.  
It should be noted that the established taxes for causing damage to red-listed plants are uniform and do not depend on the status of the object. In this regard, the implementation of a differential taxation system, tailored to the specific characteristics of each species and their status (i.e., relict, endemic, rare, vulnerable, endangered, etc. ), is deemed essential. Since these categories reflect the quantitative and qualitative composition of the flora, it is advisable to implement a differential system of taxation. For example, the price for a single specimen of C. _subvillosum_ (a relict, endemic, rare species with low abundance) is unreasonably low and should be revised upwards. A review of publications concerning rare and endemic plant species of Lake Baikal's coast [46; 47; 48; 49; 50] identified the necessity for additional research in the following areas: (1) integrated ecological-biological and molecular-genetic studies of plants; (2) the influence of abiotic factors on their condition; (3) the impact of recreational activities; (4) the mechanisms of species adaptation to climatic changes and anthropogenic load; and (5) the development of measures (as well as an assessment of their effectiveness) for the protection, conservation, and restoration of populations. The use of water resources of Lake Baikal must be executed in a manner that ensures that the regulation of water levels does not inflict harm (or, at the very least, causes the least possible damage) to the region's flora and fauna while concurrently minimizing damage to socio-economic objects. At the same time, the preservation of the unique ecological system of Lake Baikal--a UNESCO World Heritage Site--appears to be a priority goal.