3.1 Characteristics of publication outputs
The total publications (3,307) of all types in the SCI-E related to hydrological connectivity from 1998 to 2018 were shown in Fig.1. Among all types of publications, the articles occupy the dominant position, comprising 90% of the total publications, followed by proceedings, reviews, and others. Since Vannote proposed the concept “river continuum” in 1980, hydrological connectivity had gradually come into people’s sight (Vannote et al., 1980). As time comes to 2005, the publications number increased significantly and over 100, 250, and 400 papers were published in 2008, 2014, and 2018, respectively. In addition, it can be seen that although the number of the published papers in 2010, 2012 and 2016 is less than the previous year, the overall trend shows a continuous rise. The annual average was 14.88%, especially in 2017 and 2018, obtained the growth rates of 15.06% and 15.10%, respectively.
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