The contribution of vascular plant species to alpha- and beta-diversity in dry and mesophytic meadows in the middle taiga of Karelia

It is known that alpha-diversity values are mainly formed by a small number of relatively common species. In this work, we set the task to outline a list of such species and determine the final value of the coefficient of determination R2 that they provide. For this purpose, we sorted the species in the table according to the maximum R2 between the alpha or beta diversity indices and the number of model species or their total abundance. The work was carried out on the basis of the analysis of data on flora and vegetation of 146 meadow areas in the middle taiga part of the Republic of Karelia. (Northwest Russia). It turned out that the final value of alpha diversity was 80% dependent on the presence of 27% of the species found in the meadows of the region and 86% on the abundance of a slightly smaller number of species. At the same time, 74 % of it depended on the presence of some 7 % of species, and 81 % - on the abundance of about the same number of species. The species that determine patterns of alpha diversity are mostly grassland, and the gradient of alpha diversity is largely determined by the ecological and syntaxonomic gradient between communities. The beta diversity depends much more strongly on stochastic processes, the maximum value of R2 does not reach 0.5 The species that determine the patterns of beta diversity are mostly relatively rare and, according to the biotopic character, are mostly not related to meadows. Presumably, to a large extent, the beta diversity of meadow vegetation is formed by anthropogenic disturbances, and to a lesser extent, by the natural topical heterogeneity of meadow sites.