Monitoring of species diversity in the herbaceous layer of mixed forests on the central Russian plain

The diversity and structure of the herbaceous layer were monitored on a transect through mixed forests in the Malinskaya Biogeocenotic Station (Moscow oblast, Russia). The data obtained in 1987 and 1997 were compared. The parameters of species rank distribution, number of species, and entropy estimate of specie diversity only slightly changed during that period. The total coverage and abundance changed substantially; statistically significant changes in the contributions of species to the community were revealed. Estimates of changes in the community status of species belonging to different ecological groups on the Ellenberg scale served as the basis to demonstrate that soils were eutrophicated and the climate became more continental during the period of the study. Transformations of the vegetation structure were found to be equilibrium; and the community, to exhibit elements of self-organization.