Management and control methods of invasive alien freshwater aquatic plants: a review

Introduced invasive alien aquatic plants (IAAPs) threaten ecosystems due to their excessive growth and have both ecological and economic impacts. To minimize these impacts, effective management of IAAPs is required according to national or international laws and regulations (e.g. the new EU regulation 1143/2014). Prevention of the introduction of IAAPs is considered the most cost effective management option. If/when prevention fails, early detection and rapid response increases the likelihood of eradication of the IAAPs and can minimize on-going management costs. For effective weed control (eradication and/or reduction), a variety of management techniques may be used. The goal or outcome of management interventions may vary depending on the site (i.e. a single waterbody, or a region with multiple waterbodies) and the feasibility of achieving the goal with the tools or methods available. Broadly defined management goals fall into three different categories of, containment, reduction or nuisance control and eradication. Management of IAAP utilises a range of control methods, either alone or in combination, to achieve a successful outcome. Here we review the biological, chemical and mechanical control methods for IAAPs, with a focus on the temperate and subtropical regions of the world and provide a management diagram illustrating the relationships between the state of the ecosystem, the management goals, outcomes and tools.