Abstract
Charophyte algae is a very sensitive group of organisms occupying Kazakhstan waterbodies. They are distributed throughout the country; however, not enough studies have been conducted, especially in the southern region. Research carried out in 2019–2022 identified 33 habitats of charophyte algae in the south and southeastern regions of Kazakhstan, including 15 new to Kazakhstan. Bioindicators and the statistical analysis of 223 species of nine phyla of microalgae associated with charophytes revealed that the main factors influencing the distribution of algal diversity may be habitat altitude and hydrology. The habitat altitude of about 700 m above sea level was shown to be the boundary between the different diversity distributions. The application of bioindicator methods can expand our knowledge on the ecology of the charophyte species in Kazakhstan. The study of algal diversity in charophyte habitats can serve as a tool for tracking climate change under potential future climate warming.