Ontogenetic Structure and Assessment of Аlyssum lenense (Brassicaceae) Coenopopulations in the Central Yakutia
<b>Abstract</b>—<i>Alyssum lenense</i> Adam. is an early flowering species in Brassicaceae family. In Yakutia, it is distributed along the Lena river valley from its upper reaches and up to 70 degrees north. It usually grows occurs the steppes and on rocky slopes, rarely in dry pine forests. The studied <i>Alyssum lenense</i> coenopopulations from the Central part of the Yakutia are normal, incomplete and young. Coenopopulations with left-handed ontogenetic spectra (with predominance of virginile individuals) are formed on dry steppe slopes of the bedrock bank of the Lena River mostly in a protected area, with no anthropogenic impact, and also on floodplain terrace in pine forest in shady and relatively humid conditions. The centered type of ontogenetic spectra (with predominance of generative individuals) is observed in steppe parts on the slopes of the bedrock bank of the river and on the floodplain terrace exposed to intensive grazing, and also on artificial slope with sloughing soil. Assessment of the state of <i>Alyssum lenense</i> coenopopulations according to organismal and population features showed that the most favourable conditions for the coenopopulations are found in ungrazed areas and related to the protected habitats. Grazing negatively affects species growth density and their organismal features. Thus, the coenopopulations growing on the dry slopes of the bedrock river bank are less resistant to grazing. The ontogenetic survival strategy of <i>A. lenense</i> is defined as stressful.