Invasion of Alien Solidago Taxa into Urban Habitats: A Study of Selected Towns in Southern Poland

Abstract In Poland there are three invasive species of the genus Solidago native to North America. In the years 2010-2015 field survey in five tows in Oswiecim Basin and its vicinity was performed which aimed to examine frequency, habitat preferences and basic parameters of populations of these species. Amongst invasive goldenrods S. canadensis (79 localities) and S. gigantea (74) prevailed in the study area and are much more frequent than S. graminifolia (8). Populations of goldenrods were not very abundant and did not occupy large area, however, there were populations exceeding 500 m2 and that had more than 500 ramets except for S. graminifolia which occur at low densities. The Canadian goldenrod S. canadensis tended to occur more frequently in ruderal and segetal habitats than S. gigantea whereas S. graminifolia was encountered only at fallows. Both S. gigantea and S. canadensis were reported to occur in wetland habitats and sometimes formed monospecific stands what prove negative influence on biodiversity.