# Impact of High Water Levels in Lake Baikal on Rare Plant Species in the Coastal Zone
## 2 Materials and Methods
### Object of Study  
The flora of Lake Baikal shores is distinguished by a prevalence of endemic species, which have evolved in response to unique environmental conditions, thereby facilitating  
Figure 1: Location of study area. The research on high water levels’ impact on rare plant species was carried out on the southeastern coast of Lake Baikal.  
the conservation of paleoendemics and the emergence of neoendemics. However, species exhibiting a combination of unique and specific natural characteristics in their habitats, in conjunction with substantial natural and anthropogenic pressures, are particularly vulnerable. Changes in water regime and recreational load can lead to the disturbance of the natural habitat of rare plant species, potentially leading to their injury and gradual destruction. The species growing on the littoral zone, i.e., the sandy surf strips and gravels along the eastern shore of Lake Baikal, are the first to experience the negative impact of the water-level regime: _Deschampsia turczaninowii_ [PERSON], _Craniospermum subvillosum_ [PERSON], _Corisperum ulopterum_ [PERSON], and _Astragalus sericeocanus_ [PERSON] (Figure 2). According to the Red Data Book of the Republic of Buryatia, all of these species are classified as rare, with no current risk of extinction. However, their population sizes are limited, and their distribution is so restricted that they may face extinction under the threat of unfavorable changes in habitat, whether natural or anthropogenic in origin. These species correspond to category 3 of the Red Data Book of the Russian Federation and Near Threatened (NT) categories of the IUCN Red List [30]. Exogenous geomorphological processes along the lake's shoreline, alterations in water level, contamination, and the accumulation of industrial and domestic waste, along with substantial recreational impact, collectively pose a threat to the viability of these rare populations.  
Figure 2: Rare and endemic plant species: (**a**) _C. subvillosum_; (**b**) _C. ulopterum_; (**c**) _D. turczaninowii_; (**d**) _A. sericeocanus_. Photo by BINM SB RAS, [PERSON] during the vegetation period.  
Deschampsia turczaninowii--herbaceous dense turf polycarpic of the Poaceae family, endemic to the shore of Lake Baikal. It grows on sandy-pebbly, stony substrates near the water's edge, within the splash zone. It is sporadically distributed and does not form closed-stand communities [30].  
Craniospermn subvillosum--herbaceous, short-rooted, rosette-forming perennial plant of the Boraginaceae family. It is an obligate psammophyte; a rare, endemic species; a Paleogene relict of a psammophytic desert-steppe landscape and cenotic group; and a xerophytic ancient Mediterranean flora. It flowers in June and fruits in early July. Its reproduction is by seed. The species grows in patches, small populations, or groups of individuals in a narrow band on coastal sandy surf berms and beaches and rarely on weakly sodded banks and stony slopes [30].  
Coriospermn ulopterum--herbaceous annual plant of the Amaranthaceae family, endemic to the shores of Lake Baikal. It grows on the sandy or sandy-rocky shores of Lake Baikal, mainly as a part of _Leymus secalinus_ communities developing along coastal banks [30].  
Astragalus sericeocanus--herbaceous long-rooted polycarpic plant of the Fabaceae family, endemic to the shores of Lake Baikal. It is a tall plant with ascending 30-50 cm long shoots, whitish-graysh from dense semi-branching white mossy pubescence. Blooms in June to early August and fruits in August. It reproduces by seeds. The geographical distribution of this species is limited to two localities: the southeastern coast of Lake Baikal (Peski area, between the Turka River and the village of Gremyachinsk) and Yarki Island at the mouth of the Upper Angara River [30]. It grows in small populations, often single specimens, on coastal shifting sands. It grows as part of mixed herb-astragalus-oxytropis lanata psammophyte communities devoid of a closed stand vegetation cover.