Comparative Assessment of Management Strategies for Invasive Aquatic Macrophytes in Freshwater Lakes

Human-driven nutrient enrichment is accelerating the spread of invasive aquatic macrophytes, generating substantial ecological and socio-economic impacts in freshwater ecosystems, including biodiversity loss, deterioration of drinking water quality, reduced fisheries productivity, constraints on recreational use as well as impaired waterborne transport. Consequently, the management of invasive aquatic weeds is now widely regarded as a priority for the conservation and sustainable use of freshwater lakes.

This study critically reviews the main control strategies currently adopted to limit the expansion of highly invasive species such as Salvinia molesta, Eichhornia crassipes, Egeria densa, Pistia stratiotes, and Elodea nuttallii. Starting from 30,659 academic and grey literature articles matching our search criteria across multiple browsers (i.e. Google Scholar, ProQuest, Web of Science, and Scopus), we critically analysed 155 fully relevant articles, focusing on lake morphology, infestation details (year of detection and species involved), strategy characteristics and their effectiveness (reduction in surface coverage and containment in the event of reappearance), as well as the qualitative and quantitative advantages and disadvantages of each method.

Our work also examines the global distribution of such management practices and integrates satellite-based remote sensing data to quantify macrophyte surface coverage in lake environments pre‑ and post‑control. Our results to date have identified three dominant approaches: mechanical removal (in 15.6% of the cases), chemical herbicide application (19.5%), and biological control (28.6%), alongside integrated management combining the former approaches (28.6%) and other treatments (7.8%).

Mechanical harvesting and chemical treatments can rapidly reduce biomass, yet their long-term application is often constrained by high operational costs and, in the case of herbicides, potential environmental risks. Biological control, typically involving specialist insects or herbivorous fish, appears to offer a more sustainable and self-maintaining option (with a recurrence rate of 11.4% of the cases, compared with 33.3% for chemical approaches and 41.7% for mechanical treatments), although its effectiveness depends on predator–prey specificity and the suitability of local climatic conditions.

In terms of geographical distribution, the case studies were unevenly distributed, with 40.8% located in North America (which shows a predominance of chemical treatment accounting for 36.7% of the total, particularly in the United States), 25.0% in Africa (where 70.0% of the cases involved biocontrol), and a smaller share in Oceania and Asia (representing 20.0% and 10.8% of the total, respectively), with an even smaller proportion in Europe and South America.

By comparing the strengths, limitations, and context-dependent requirements of each method, this study supports the selection of appropriate management strategies for future case studies, taking into account ecological characteristics, invasion dynamics, geographic setting, and available economic resources.