Structure of the Coenopopulations of Dracocephalum ruyschiana L. (Lamiaceae, Magnoliopsida) in the Altai Mountains (Russia) in Various Years

The structure of two coenopopulations (CP 1 and CP 2) of Dracocephalum ruyschiana L. located in different ecological and cenotic conditions of the Altai Mountains is considered for various years. The monomodality of the ontogenetic spectra with the predominance of mature generative individuals has been established. In the ontogenetic spectra, there is an accumulation of young plants and a reduction in the proportion of old individuals. A density drop in CP 1 from 2004 to 2022 and an increase in CP 2 from 2008 to 2022 were revealed. The calculated demographic indicators and those of the development rate confirm the rejuvenation of the studied CPs. According to the delta-omega classification, CP 1 develops from aging to mature, while the type of CP 2 has not changed, it remains mature. Our CP analysis shows a significant vulnerability of the demographic indicators from nonsimultaneous germination of seeds due to their different dormancy and the amount of precipitation. In addition, the changes in the ontogenetic structure and demographic indicators in 2022 are caused by overgrowth of the communities with shrubs, namely, Caragana arborescens Lam., Spiraea trilobata L., and Cotoneaster niger (Ehrh.) Fr. in CP 1, and the presence of plant debris in CP 2.