Współwystępowanie Niecierpka drobnokwiatowego Impatiens parviflora i wybranych roślin lasu dębowo-grabowego w Wielkopolskim Parku Narodowym

The aim of this study was to determine the mutual effect of small balsam (Impatiens parviflora) and other elements of phytocoenosis on their position in the community. In the oak−hornbeam forest of the Wielkopolski National Park, Ficaria verna, Carpinus betulus self−seedlings, Vaccinium myrtillus, Galium odoratum, Pteridium aquilinum and tuft grasses were found to have locally strong inhibitory effect on small balsam growth. The effects of the interaction between Impatiens parviflora and other plants of the herbaceous layer depended not only on plant competitiveness but also on how long was the period of their co−occurrence during the growing season (i.e. on species phenology) and local differences of habitat conditions. Wherever Impatiens parviflora was a dominant species the interspecies competitive pressure (w) and species diversity H' of the herbaceous layer were highest.