3.2 Subject category distribution
The co-occurrence analysis of
subject categories was conducted. As the co-occurrence network from 1998
to 2018 shown in Fig. 2,
Environment Science and Ecology is
the most popular research area (frequency, 1,413) above all. The others
of top 3 are Water Resources
(1,135) and Environmental Sciences (1,029). In addition, Fig. 2 displays
some nodes have high centrality as there are purple outer cycles
surrounding them, the details are shown in Table 1. Among the top 15
subject categories, Environmental Sciences has the highest centrality in
hydrological connectivity. The second is Biodiversity and Conservation,
followed by Geosciences, Multidisciplinary, Ecology, physical Geography.
Therefore, the study of hydrological connectivity is carried out within
the scope of a multidisciplinary diversity, from Environmental Sciences
to Biodiversity, Water Resources, Ecology. Particularly, the Environment
Science and Ecology and Water Resources played predominant roles.
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Please Place Figure 2 and Table 1 here
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