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3. Literature analyses

We understand that the BRI currently is at the early stage, which is still undergoing a global expansion progressing (Hughes et al., 2020), as more countries continue to join the program. In this review, we considered that the potential BRI developments and the resulting impacts are predominantly located across the ECs, given that these regions are mainly composed of developing countries that need urgent economic development and infrastructure construction. In line of this respect, Sixty-six countries were involved in the BRI program that are located among the E and SE Asia, the “Association of Southeast Asian Nations ” (ASEAN), W Asia, S Asia, C Asia, Russia and surrounding countries and C and E Europe (Figure 1). A bibliographic search of relevant literatures was conducted in June 2020, in prior to analysing the desertification patterns in these countries.
The literature search was conducted via “Thomson Reuters© , Web of Science , and Google Scholar through using the key words “Desertification ” + “BRI ” and “Desertification ” + “Each of the BRI countries ”. Based on a preliminary search, we found that the number of journal articles about the topic was relatively limited for the BRI region, suggesting that the desertification along the BRI has not received sufficient research attention, a similar situation to desertification research on wider dryland areas (Martínez-Valderrama et al., 2020). In order to obtain as much information as possible for a comprehensive review, we extended the search to include books, grey literature, newspapers and official webpages. As a result, we initially retrieved 185 items. A further check of each of the items was then done and only those directly relevant to desertification and its control in the BRI region were included in this study. Finally, we found 163 items for a further analysis, including journal articles (103), books and book chapters (16), conference papers (20), grey literature (e.g. policy and governmental documents, 19), newspaper (3) and webpages (2) from 1980s to 2020. The searched literature covers studies that are relevant to desertification over the BRI countries.
We found that between the years of 1980 and 2001, the number of literatures related to desertification in the BRI countries remained at low numbers (no more than 3 items per year) (Figure 2). However, between the years of 2001 and 2020, there was an increase in the concerns about desertification, reflected by the amount of publications and research outputs. The number of publications keep on staying at a high level between 2018 and 2020, over which about 10 items were published per year. All the selected literature was carefully checked to collect the information relevant to the aim of our study, the information was summarized into tables (i.e. Tables 1-5) to facilitate an in-depth and unbiased analysis and comparison. Research progress and future research need were then described and discussed.