Distribution and management of Fallopia japonica in riparian biotopes in Slovakia and Austria

Abstract

Globally, invasive species represent a serious threat to biodiversity and to the ecosystem. As an undesirable part of riparian ecosystems, invasive plants form continuous growths on the banks of watercourses. One of the biggest problems at river bank sites is Japanese knotweed, Fallopia japonica (Houtt.) Ronse Decr, which is an extremely invasive and aggressive weed. The topic of the interaction of flow and invasive plant species in shore stands is rich and presents a wide range of possibilities for research. The presented paper brings the results of our studies on the invasions of F. japonica in chosen riparian vegetation sites in Austria and Slovakia from 2011–2020 (36 stands). Our research was aimed at the survey on the changes in the distribution (spread) of F. japonica at the selected river sites; assessment of the impact of the watercourse regime on the spread of F. japonica; monitoring of the population growth dynamics of F. japonica and assessment of possibilities for effective eradication of F. japonica in context of the riparian vegetation management. We used standard techniques of field survey, mapping, flow modeling/simulation, and laboratory experiments. Our research results showed that water streams are not primary invasion starters until there is a flood. As long as flooding does not exceed the critical speed of the water stream, there is no direct damage to the invasive plant. The water body can be a secondary trigger for plant invasion at normal speeds. In addition, F. japonica reproduction ability directly conditions its population dynamic growth. We can report that selective invasion removal adapted to local conditions can be most suitable and beneficial for municipalities.

Spatial patterns and effects of invasive plants on soil microbial activity and diversity along river corridors

“…On one hand, this increases diversity contributing to ecosystem stability at both the local and landscape level. On the other hand, such routes also allow the spread of non-native species, some of them having a truly invasive potential such as Fallopia sp., Helianthus tuberosus or Impatiens glandulifera (Čuda et al 2020;Hejda et al 2009;Vaseková et al 2022).…”

“…This is re ected in theoretical models emphasizing biological processes (river continuum concept; Vanote et al (Besemer et al 2013). In the Carpathian region, they are not spared of the presence of invasive plants, especially in their lower parts crossing human-affected or arti cial habitats (Vaseková et al 2022). Studies on the effects of invasive plants on soil microbiota often focus on taxonomical diversity of soil communities (e.g., Sapsford et al 2022).…”