Invasive Asian Knotweeds: Is Bioengineering Beneficial for Soil Chemical Quality and Biodiversity in Riverbank Restoration?

Abstract

Invasive alien species represent a threat to biodiversity at a global scale. Among the most problematic terrestrial plants in France and Europe, Asian knotweeds (Reynoutria spp.) often pose challenges as their management is costly and uncertain. First, managers have to decide whether to act or not. To do so, they need a better understanding of the potential consequences of their management, particularly on the functioning of the ecosystem concerned.
Then, managers have to decide which technique to use. Plant bioengineering techniques are based on the reintroduction of indigenous competitive plant species as seedlings or cuttings. They are increasingly used as they reduce the dominance of the invasive alien species and reintroduce plant diversity. Although many plant bioengineering operations have been carried out, they have only exceptionally been monitored over time, and their effectiveness in restoring plant and soil diversity and ecosystem functioning has never been evaluated. This study assess the effects of Asian knotweeds and their restoration through plant bioengineering on plant communities and soil, based on a detailed analysis of soil chemistry and fauna.