PARENT SESSION
Poster Session: Ecological Impacts of Invasive Plants
Tuesday, November 4, 2003, 5:00 PM to 7:00 PM
Global Ballroom

American vascular plant species naturalised in the flora of Poland.

Tokarska-Guzik, Barbara¹, ¹ University of Silesia, Katowice, Poland

ABSTRACT- The discovery of the Americas and the consequent breaching of the geographical barrier which was the Atlantic Ocean has had an important role in the process of flora exchange. During the last five hundred years the flora of Poland has been enriched by 103 alien species of American origin which are currently recognised as naturalised. This group is represented by 36 families, of which Asteraceae(27 species), Onagraceae (11) and Rosaceae (11) are the most important. The American flora established in Poland is characterised by the preponderance of long-lived perennial herbs (35), woody plants (34 species) and annuals (32). Among 61 species for which the first record for Poland are available the majority arrived to Poland in the second half of the 19th and in the first half of the 20th centuries. Only six species (Chamomilla suaveolens, Conyza canadensis, Galinsoga parviflora, Amaranthus retroflexus, Oxalis stricta and G. ciliata) are common (occurring in 60-90% of 10 x 10 km squares; the total number of squares for Poland is 3283). Eleven species are abundant (occurring in 20-60% of 10 x 10 km squares), others are locally abundant (26 species occurring in 3-20% of 10 x 10 km squares) and rare. The distribution data for about 7 species needs to be verified and for 30 species distribution maps still need to be produced. The common American species in Poland grow mainly in disturbed habitats. Over 50 species belong to a group most successful in migrating into natural communities. Robinia pseudoacacia, Elodea canadensis, Solidago gigantea, Juncus tenuis, Lupinus polyphyllus, Acer negundo, Solidago canadensis, Padus serotina, Bidens frondosa, Rudbeckia laciniata, Helianthus tuberosus, Echinocystis lobata and Quercus rubra are widely distributed species which also colonise natural habitats. Most of the above-mentioned species have been classified as invasive plants in Poland. Some particular habitat such as watersides are the most endangered and are most easily invaded by American invasive plants and then play a role as a transmitter into other habitats such as bushes and woodland.

Key words: invasive species, naturalised species, alien flora, Poland