Abstract
The participation of species of alien origin in the flora of individual regions of the world is increasing. A large proportion of these species pose a threat to biodiversity. Issues of the dynamics of changes in the flora and the scale and pace of the processes, with particular emphasis on the biology, ecology, chorology, and genetic variability of the populations of plants of alien origin, including those alien species which are invasive, have been the subject of many years of research in this field in Poland. The present study is an overview of the state of research on invasive plant species in Poland, including the main results of the basic and applied research which have provided the basis for (i) the preparation of a list of invasive plant species for Poland; (ii) assessing the degree of invasiveness of the species analysed, in accordance with the adoption of criteria and the development of methodological solutions. In this work, a new version of the list of invasive plant species has been prepared on the basis of earlier studies, combining theoretical and practical aspects of definition, and it is compared with the list of invasive alien plant species considered to constitute a threat to the EU and Poland as a member country. The categorization (risk assessment) of invasive alien species along with the identification of the most endangered types of natural habitats is often used in practice in the management of invasive plants in Poland. The results of our research have fed into the formulation of legal regulations at the global and regional levels.