Abstract
tImpatiens parviflora (Balsaminaceae) is one of the most widespread invasive plant species in CentralEurope. Nevertheless, both mechanisms and consequences of its invasion are still poorly understood.
Inthis study we attempt to understand the impact of this species on native vegetation.The impact of I. parviflora on native vegetation was studied using removal experiment on permanentplots in oak-hornbeam forests in central Bohemia, Czech Republic. Nine pairs of plots were establishedin invaded vegetation, one plot in each pair stayed invaded and the other served as removal plot andall I. parviflora individuals were repeatedly removed from the plot.
Species composition in 4 subsequentyears was recorded in the plots. Species response to I. parviflora removal was correlated to plant traits toreveal trait characteristics of species suppressed by the invasion.Significant increase in both numbers and cover of native species was observed in removal plots incomparison with invaded plots during the experiment, with the greatest change in first two years afterinvader removal.
Species composition also significantly differed between invaded and removal plots.Species with high affinity to removal plots, i.e. species that are most restricted by I. parviflora invasion,were mostly species with small releasing height and early start of flowering.Our results indicate that I. parviflora has negative impact on native vegetation but that the vegeta-tion can recover within few years after the invader removal. Due to its extensive distribution and highturnover, removal of the species from larger plots is, however, not realistic in practice.