Comprehensive Analysis of Invasive Flora of Russia

The article presents the results of an analysis of the invasive flora of Russia based on the materials contained in the database IRIS: Study of Plant Invasions of the Country. The taxonomic, biomorphological, and chorological structure of the invasive flora, as well as the lag-phase of the most aggressive species in their regions of occurrence, have been analyzed. Invasive species (586 species from 351 genera and 87 families) are considered as a group of alien naturalizing neophytes: archaeophytes and ephemerophytes are not included in this category, nor are native species that cause ecological, socioeconomic damage. The invasive flora is characterized by the predominance of unintentionally introduced North American species, which spread from the secondary ranges previously formed in Europe. The leading families in terms of the number of species are Asteraceae, Poaceae, Fabaceae, Rosaceae, Brassicaceae, Amaranthaceae, Apiaceae, Lamiaceae, Boraginaceae, and Plantaginaceae. Annual herbaceous plants are the predominant in the spectrum of life forms (42%), the proportion of perennial herbaceous plants is lower (34%), and woody plants are less represented (24%). In the chorological spectrum, the leading position is occupied by widespread species with Eurasian (32%), American (19%), and Asian (15%) types of natural ranges. The features of the distribution of the taxonomic and life forms of invasive species according to federal districts are described. Relatively few species exhibit the Holarctic type of range, as well as hemicosmopolitan species, which does not support the existing hypothesis of a more successful invasion of species with wide primary ranges. Erigeron canadensis and Acer negundo are the longest-standing invasive species. Their first herbarium specimens were collected in 1781. The lag-phase of invasive species varies from 2 to 220 years. A tendency toward reduction in the lag-phase of growth of alien species during their subsequent dispersal in the country was noted. A new indicator “the territory invasiveness index” is proposed. This indicator reflects the degree of negative impact of alien invasive species. It is noted that the Central and Volga Federal Districts are the most strongly affected, and the North Caucasian Federal District is the least affected. The article highlights the current state of plant invasions in Russia, identifies gaps in research, and outlines ways for further research to document invasions of alien plants.