Changes in species diversity and floristic composition over sixty years in plant communities with Aflatunia ulmifolia in mountainous Kazakhstan

Background: The impact of environmental drivers of biodiversity change on the native vegetation of Kazakhstan is so far poorly understood. Aims: To compare historical and contemporary data on the floristic composition of plant communities with Aflatunia ulmifolia against the backdrop of sixty years of climate and land-use change. Methods: In 2021-2022, we revisited a river gorge in the Dzhungarskiy Alatau that had been originally surveyed in 1962. We estimated floristic composition and abundance of species on the Drude scale, and evaluated floristic similarity and abundance change between our dataset and that of 1962. Results: In total, 226 species belonging to 166 genera and 52 families were recorded. The vast majority were native, and only 8 species were exotic. Historical surveys recorded 104 species, and recent surveys, 199 species, the surveys from the two observation periods sharing only 77 species. The Sorensen similarity coefficient was the highest for native shrubs (0.8), and the lowest for native herbaceous plants (0.46). The increase in floristic diversity was largely due to the increase in the number of herbaceous species, mostly perennial forbs. Conclusions: The observed changes could be a result of increased frequency of shallow landslides, grazing exclusion, and growing human presence.