Aquatic Botany 136 (2017) 112–137 Contents lists available at ScienceDirect Aquatic Botany jou rnal homepage: www.elsevier.com/locate/aquabot Review Management and control methods of invasive alien freshwater aquatic plants: A review a,b,∗ c d d d e A. Hussner , I. Stiers , M.J.J.M. Verhofstad , E.S. Bakker , B.M.C. Grutters , J. Haury , f g h i j J.L.C.H. van Valkenburg , G. Brundu , J. Newman , J.S. Clayton , L.W.J. Anderson , i D. Hofstra a Institute of Botany, Heinrich-Heine-University, D-40225 Düsseldorf, Germany b Jackels Umweltdienste GmbH, D-41334 Nettetal, Germany c Plant Biology and Nature Management (APNA), Department of Biology, Vrije Universiteit Brussel, 1050 Brussels, Belgium d Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB, Wageningen, The Netherlands e Department of Ecology, UMR ESE, AGROCAMPUS OUEST, 35042 Rennes Cedex, France f Netherlands Food and Consumer Product Safety Authority, National Reference Centre, P.O. Box 9102, 6700 HC, Wageningen, The Netherlands g Department of Agriculture, University of Sassari, 07100 Sassari, Italy h Centre for Ecology & Hydrology, Wallingford, Oxon, United Kingdom i National Institute of Water and Atmospheric Research, PO Box 11115, Hamilton, New Zealand j Waterweed Solutions, P.O. Box 807, Pt. Reyes Station, CA, 94956, United States a r t i c l e i n f o a b s t r a c t Article history: Introduced invasive alien aquatic plants (IAAPs) threaten ecosystems due to their excessive growth Received 27 April 2016 and have both ecological and economic impacts. To minimize these impacts, effective management of Received in revised form 2 August 2016 IAAPs is required according to national or international laws and regulations (e.g. the new EU regulation Accepted 2 August 2016 1143/2014). Prevention of the introduction of IAAPs is considered the most cost effective management Available online 23 September 2016 option. If/when prevention fails, early detection and rapid response increases the likelihood of eradica- tion of the IAAPs and can minimize on-going management costs. For effective weed control (eradication Keywords: and/or reduction), a variety of management techniques may be used. The goal or outcome of manage- Biological control ment interventions may vary depending on the site (i.e. a single waterbody, or a region with multiple Chemical control Eradication waterbodies) and the feasibility of achieving the goal with the tools or methods available. Broadly defined Early detection management goals fall into three different categories of, containment, reduction or nuisance control and EU regulation 1143/2014 eradication. Management of IAAP utilises a range of control methods, either alone or in combination, to Macrophyte achieve a successful outcome. Here we review the biological, chemical and mechanical control methods Management costs for IAAPs, with a focus on the temperate and subtropical regions of the world and provide a manage- Mechanical control ment diagram illustrating the relationships between the state of the ecosystem, the management goals, Rapid control outcomes and tools. © 2016 Elsevier B.V. All rights reserved. Contents 1. Introduction . 113 1.1. The crucial role of aquatic vegetation for ecosystem functioning . 113 1.2. When does an introduced plant become invasive? . 114 1.3. Social and political context of freshwater invasions: implications for management. .115 2. Methodology. .115 2.1. Definitions . 115 2.1.1. Freshwater aquatic plants . 115 2.1.2. Terminology . 116 3. Prevention, early detection and biology of IAAPs . 116 ∗ Corresponding author at: Institute of Botany, Heinrich-Heine-University, Universitätsstr. 1, Building 26.13.O2, D-40225 Düsseldorf, Germany. E-mail address: [email protected] (A. Hussner). http://dx.doi.org/10.1016/j.aquabot.2016.08.002 0304-3770/© 2016 Elsevier B.V. All rights reserved. A. Hussner et al. / Aquatic Botany 136 (2017) 112–137 113 3.1. Prevention is cheaper than control . 116 3.2. Early warning and rapid response . 116 3.3. Importance of knowledge on weed biology for successful management . 117 3.3.1. Investigating the ecosystems after IAAPs introduction . 117 3.3.2. Vegetative and sexual reproduction of IAAPs . 117 3.3.3. Dispersal of IAAPs . 117 3.3.4. Different growth forms of IAAPs require different management methods . 117 3.4. The crucial role of the habitat type on the potential success of management strategies . 117 3.5. Defining the goal: containment, reduction, eradication . 118 4. Management options for IAAPs and their pros and cons . 118 4.1. Mechanical and physical control methods (Table 2) . 118 4.1.1. Mechanical harvesting and cutting of submerged weeds . 118 4.1.2. Mechanical excavation . 119 4.1.3. Hydro-Venturi (water jets) . 120 4.1.4. Suction dredging (and diver-assisted suction removal) . 120 4.1.5. Manual harvesting (hand-weeding) . 122 4.1.6. Bottom shading with benthic barriers and substrate. .125 4.1.7. Water level drawdown. .126 4.1.8. Dye application. .126 4.1.9. Nutrient reduction . 126 4.2. Biological control (Table 3) . ..