Рhytocenotic characteristics of the communities with participation of the Аlyssum lenense in the Lena River valley

Abstract

The phytocenotic characteristic of the steppe communities with the participation of the springblooming species Alyssum lenense in the middle reaches of the Lena River valley is considered. The objects of the study were 11 communities, described at 4 locations at different distances from Yakutsk in 2019. Тhe species similarity of the communities (Sørensen coefficient K_s) was determined by the formula K_s = 2c / (a+b) · 100. The study area is characterized by a sharply continental climate, which manifests itself in low winter, high summer temperatures and high aridity (average annual rainfall is 192 mm). The Alyssum lenense species is a component of feather stipas, agropyrons, festucas, pulsatillas, artemisiacommutatas, artemisiafrigidas, developed on the southern slopes of the Lena River valley, as well as the grassy layer of the sparse dry pinus forests and their edges, common in the river valley. Communities with the Alyssum lenense participation are of low diversity and include 9 to 19 species. The species diversity of the studied communities is predominantly represented by species of the steppe complex; species with oriental genetic ties predominate. In the biomorph spectrum, rooted plants and turfy cereals, characteristic of dry habitats, are most steadily represented. In the communities with the participation of Alyssum lenense, species listed in the Red Book of the Republic of Sakha (Yakutia) grow – endangered species Gagea pauciflora, reducing the number of populations – Ephedra monosperma. Allium prostratum, A. ramosum, Krascheninnikovia lenensis, and the narrow-local endemic of middle reaches of the Lena River valley – Astragalus lenensis.