Results Temporal trend and regional distribution We identified an increasing trend of empirical research on tourists’ valuation of nature in protected areas from 1977 to 2021, in which different valuation techniques were used (Fig. 2 ).
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Results Temporal trend and regional distribution We identified an increasing trend of empirical research on tourists’ valuation of nature in protected areas from 1977 to 2021, in which different valuation techniques were used (Fig. 2 ).