Alien and invasive plant species in plant communitiesof floodplain forests of the Malopolska Upland

During the field studies on the floodplain forests of the Malopolska Upland carried out in2009-2013, the author tried to determine which species of alien and invasive plants could be a threatto the stability of these vegetation communities. Efforts were also made to answer the question,which floodplain forests are particularly vulnerable to the penetration of alien species and in whichlayers of the forest plant community are the best conditions for the development of the individualalien plant species. During the research, a total number of 344 releves were made, of which 90recorded the presence of alien species. The most common were: Impatiensparviflora,Acer negundoand Padus serotina. The highest percentage of releves involving alien species was found in theriverside floodplain forests of Salicetum albo-fragilis and Populetum albae.