Investigation on the trends and characteristics of articles on submerged macrophytes: perception from bibliometrics between 1991 and 2018

Submerged macrophytes, as one of the most important primary producers in shallow lakes and streams, have attracted significant research attention, with relevant studies showing dynamic evolution over the past three decades. Here, we investigated the trends and characteristics of 2,836 relevant articles published between 1991 and 2018 based on bibliometric analysis. Our geographic-based results indicated a scarcity of studies on submerged macrophytes in Africa, but strong international collaboration in this field, especially that between Denmark and China. The top two core journal sources (Hydrobiologia and Aquatic Botany) of studies on submerged macrophytes were determined, with another four important sources also identified. In addition, three trends in abstract word dynamics were found over the last three decades: i.e. most frequent word (‘lake’); increased words (those related to restoration, ecosystem state, model, and macrophyte community); and decreased words (those related to fish and specific macrophyte genera). Furthermore, our case study on four macrophyte genera showed a close relationship between Hydrilla and Vallisneria and between Potamogeton and Myriophyllum, as verified via the topic-article relationships determined using the topic model. The thematic evolution map of keywords used during the last three decades showed a clear shift in scientific fields; for example, Myriophyllum spicatum was an important keyword during 1999 and 2011 but not in other periods. We found that studies on submerged macrophytes developed with an increase in applied ecology topics, such as lake restoration, and basic scientific topics, such as freshwater ecosystems and plant physiology.