Spatiotemporal changes of ecosystem services value and cross regional ecological compensation in the Yangtze River Basin

Watershed ecological compensation (WEC) aims to enhance watershed environmental protection and ecological security. However, existing studies often ignore the integrity of large-scale watershed and regional heterogeneity in economic development when determining compensation standards and allocating funds, which makes the implementation of WEC policies difficult to achieve the desired goals. This study adopts the ecosystem services value (ESV) method to quantify the ESV changes using land use data of the Yangtze River Basin (YRB) from 2005 to 2020. On this basis, a WEC standards measurement model and a funds optimization allocation model are constructed to determine the theoretical compensation standards and actual funds allocation for eleven regions in the YRB. The results show that: (1) The land-use structure tended to be stable on the whole, with forest and grassland area exceeded 60% of the total. (2) The total ESV in the YRB exhibited a gradual decline from 16,983.19 billion CNY in 2005 to 16,333.36 billion CNY in 2015, followed by a marked increase to 17,520.45 billion CNY in 2020. (3) The theoretical compensation amounts of the entire YRB were 23.86 billion CNY in 2005, 23.46 billion CNY in 2010, 23.13 billion CNY in 2015 and 24.55 billion CNY in 2020 respectively. (4) The actual compensation funds received by the districts in the YRB were all below the theoretical WEC standards as measured by ESV outputs (35.94%, 52.22%, and 83.36%, respectively). In 2020, there was a reversal, with the actual funds reaching 1.33 times the theoretical standard. This study can provide references for governments to construct WEC programs and improve the efficiency of compensation funds applicable to large-scale watersheds.