The Current State of Populations of Rhaponticum altaicum (Asteraceae) in the Northern and Central Kazakhstan

The article presented the results of the assessment of the current state of Rhaponticum altaicum populations in the Karaganda and Akmola regions (Central and Northern Kazakhstan). The research provided the phytocenotic characteristics of habitats, biological features, and ontogenetic structure of populations, as well as data on the morphological variability of the species. The floristic composition of plant communities with Rh. altaicum was analyzed for the first time. In the plant communities with Rh. altaicum, 67 species from 38 genera and 23 families were identified. Most species were herbaceous perennials (92.5%) or hemicryptophytes (68.7%). Among the ecological groups, mesophytes (32.8%) dominated, and other groups were represented by transitional species: mesoxerophytes, xeromesophytes, mesogyrophytes, and hygromesophytes (49.2%). Therefore, in nature, Rh. altaicum occupied an intermediate place between meadow-bog and meadow communities. The species preferred moist meadows on slightly and moderately saline soils. In the ontogeny of Rh. altaicum, eight age-related states were identified, from seedlings to senile plants. The analysis of morphological indices allowed estimating that Rh. altaicum stem height was the most important: so, under unfavorable growing conditions, the stem height decreased. In the majority of populations, the upper leaf width was a highly variable trait, and the length and width of the lower leaf had low or moderate morphological variability. The highest positive correlation (significant at p = 0.05) was between plant height and lower leaf length, suggesting that taller plants had longer lower leaf blades. The studied populations were mainly dominated by virgin and medium-age generative plants. Sub-senile and senile plants were not detected, which is due to the difficulty of diagnosis as well as to the increasing anthropogenic load and narrow ecological amplitude of Rh. altaicum. Our study provided new insights into Rh. altaicum biology and ecology, thereby contributing to biodiversity conservation at a regional level.