Naturalized alien flora of Uzbekistan: species richness, origin and habitats

This is the first study providing an up-to-date account of the alien flora in Uzbekistan and analyzing the relationship between the invasion status (casual, naturalized, invasive) of alien plants in this country and their life histories, regions of origin, and habitat affiliations. The data were collected from literature, herbaria, and field surveys. The check-list includes 252 species, of which 44 are invasive (17.5%), 177 naturalized non-invasive (70.2%, giving 220 naturalized species in total), and 31 casual aliens (12.3%). The family with the highest number of alien species is Asteraceae (53, or 21% of all recorded species), followed by Brassicaceae (21), Poaceae (19), and Solanaceae (15). The most represented genera in the alien flora of Uzbekistan are Amaranthus (8 species), Centaurea, Malva, Solanum, and Vicia (5 each). The majority of the alien flora of Uzbekistan are annuals (138 species, i.e., 57% of the total), followed by perennials (52 species, 21.5%). There are only 13 alien woody species recorded. Invasive species originating from Africa, temperate Asia, and Europe are over-represented, as are naturalized species native to Northern America and Southern America. The majority of species are affiliated with agricultural (204 species) and ruderal habitats (164 species); riparian habitats (68 species) and grasslands (38 species) are also well represented. The pattern of invasions in the country is determined by the interaction of source species pools arriving from native regions, their habitat affiliations, and land use. Our study provides the first step toward science-based management of plant invasions in Uzbekistan. It can support policymakers, authorities, and managers in mitigating the current and future impacts of alien species.