“…The research objects have included watersheds [28,29], forests [30], cultivated land [31], grasslands [32], wetlands [33] and many other subjects. The research content has covered the conception of ecological compensation [34], policy legislation [35], methods [36], the payment order [37] and compensation standards [38]. From the perspective of research methods, the ecological footprint method, market price method, opportunity cost method, conditional value method, environmental preference display method and alternative cost method have been the most often used approaches to calculate ecological compensation amounts [39][40][41].…”