Impact of the alien plant Impatiens glandulifera on species diversity of invaded vegetation in the northern foothills of the Tatra Mountains, Central Europe

Abstract

The impact of exotic annual Impatiens glandulifera on invaded European vegetation is ambiguous; there are studies reporting considerable negative as well as weak or even no impact of this invader on species richness and diversity of the invaded communities. The effect of invasion by I. glandulifera on species richness, diversity and the composition of resident vegetation was studied in the northern foothills of the Tatra Mountains in southern Poland. Two approaches were used: comparing diversity measures of the invaded and uninvaded plots and analysing changes in species richness and diversity in plots grouped according to increasing cover percentage of I. glandulifera. Invaded plots harboured 0.27 fewer species per 4 m 2 and had significantly reduced values of the Shannon and Simpson diversity indices and Pielou's measure of evenness. Analysis of changes in diversity measures with the increase in I. glandulifera cover revealed that an increase in I. glandulifera cover was from the onset related to a decrease in the diversity of the invaded plant communities, but after exceeding a 80% cover, this species dramatically reduced the diversity of the invaded vegetation. Non-metric multidimensional scaling analysis indicated a significant shift in the composition of invaded plots in relation to uninvaded plots, which resulted from the proportional increase in the more shade tolerant and nutrients demanding species. Our results suggest that in species-rich vegetation, such as fresh meadows and related communities, I. glandulifera may suppress weak competitors and, thus, negatively impact plant diversity. Keywords Annual exotic plant Á Himalayan Balsam Á Invasive species Á Plant invasions Á Species richness

Micro-habitat and season dependent impact of the invasive Impatiens glandulifera on native vegetation

“…German and European Union nature conservation authorities emphasize the impact on diversity and threat to other species (European Union 2014, Nehring et al 2015). Taking this study and all available ones into account, the impact of I. glandulifera on plant species diversity can be rated to be relatively low (Hejda and Pyšek 2006, Hejda et al 2009, Diekmann et al 2016, Čuda et al 2017 even if some studies showed stronger effects (Hulme and Bremner 2006, Cockel et al 2014, Kiełtyk and Delimat 2019. Indeed, we found a negative impact on the dominant natives, U. dioica and F. ulmaria, but they are in general very common and widespread in Central Europe and thus not expected to be threatened (Schreiber 1958, Weber 1995.…”

Plant palatability and trait responses to experimental warming

“…The results thus indicate that increased palatability due to increased temperature may contribute to reduced performance in cold-adapted species under future climate warming, while at the same time, these changes in palatability may increase the success of warm-adapted species 81 . Invasion success of warm-adapted species might be further strengthened by strong effects on diversity of native communities as found for another Impatiens species 82,83 .…”

CABI UK and Nagoya Protocol triggered benefit sharing

“…Each plant can produce hundreds of seeds which are forcibly ejected up to 7 m away from the parent plant, leading to the development of dense monospecific stands. These monocultures of Himalayan balsam can have negative impacts on native biodiversity, by altering the soil microbial, invertebrate and plant communities (Tanner et al 2013(Tanner et al , 2014Gaggini et al 2018;Kiełtyk and Delimat 2019). As an annual plant, Himalayan balsam stands die back in the autumn and this may have impacts on soil erosion and siltation (Greenwood et al 2020).…”