The Role of Non-Native Plant Species in Modulating Riverbank Erosion: A Systematic Review

Riverbank erosion is a naturally occurring process that influences riparian zone habitats. However, anthropogenic activities are increasing rates of riverbank erosion. Climate change and hydrological and physical modifications drive riparian zone perturbations. Whilst native riparian vegetation can reduce riverbank erosion, the proliferation of non-native riparian plant species has been linked to riverbank instability, with marked changes in fluvial erosional regimes attributed to invasion by species such as Impatiens glandulifera (Himalayan Balsam) or Tamarix (Tamarisk) into riparian zones. Yet, the role of non-native plant species in modulating riverbank erosion remains unclear, in part due to the lack of investigations that quantify geomorphic change. We systematically assessed the relevant ecological and geomorphological literature to determine current understanding and to offer recommendations for future research on non-native plant-riverbank erosion. Included articles focused on a limited number of non-native plant species across a restricted range of habitats types, with dependency on topographic change and generally short study duration obscuring potential causal links or feedback cycles. It is critical in the face of parallel rapid proliferation of riparian non-native plant species and climate change effects, that we improve mechanistic understanding of their role in riverbank erosion.