An analysis of publications on invasive macrophytes in aquatic ecosystems

In this study, we performed a scientometric analysis of published scientific papers on the biological invasion of macrophytes in freshwater ecosystems to assess the main trends and gaps in research concerning this group of organisms. The analysis showed that publications on invasive macrophytes increased exponentially in the last decade. However, the activity index (a comparison of the quantitative trends of invasive macrophytes in relation to all of the papers on macrophytes) indicated that invasive macrophytes have not been consistently studied more than other topics in the field of limnology over the last decade. The most studied macrophyte species were Myriophyllum spicatum, Hydrilla verticillata, Phragmites australis and Eichhornia crassipes. Certain gaps were related to the limited number of studies on the important species threatening tropical ecosystems, under-representation of investigations on the impacts of invasive macrophytes on fish and lack of studies associating macrophytes with microorganisms (bacteria and fungi). Studies that encompassed several levels of biological complexity were also scarce, indicating that the studies were fragmented at specific levels. Finally, there was a clear geographical bias, with fewer studies occurring in Neotropical and Afrotropical regions. Identification of these gaps may be useful for addressing future studies that might help evaluate the causes of invasion by macrophytes and the impacts of such invasions on freshwater ecosystems. (AU)