A comparative study on the spatial distribution characteristics and the driving factors of protected river systems between China and the United States of America

The National Water Park System (NWPS) in China and the National Wild and Scenic Rivers System (NWSRS) in the United States represent typical protected river systems (PRSs) for conservation of water resources. This study used spatial analysis methods to characterize and compare the aggregated distribution of two types of PRSs and further explored the reasons for their differences in spatial distribution. The results showed that the highest concentrations of National Water Parks (NWPs) were along the east coast and adjacent central areas, accounting for 69.48% of all 878 units, and 59.45% of the NWPs were concentrated in the plain area characterized by a high temperature, high humidity and high nighttime light. The spatial distribution of NWPs was positively correlated with altitude, drainage density, population density, GDP/km², and dam density in each province, while not correlated with forest coverage. In contrast, National Wild and Scenic Rivers (NWSRs) were concentrated along west coasts areas, accounting for 56.88% of all 218 units, and 78.84% of NWSRs were concentrated in mountainous areas near coastlines, characterized by a high humidity and low nighttime light. The spatial distribution of NWSRs in each state was positively correlated with areas of high forest coverage, while negatively related to altitude. There was no correlation between the NWSRs distribution with population density, GDP/km², dam density and drainage density. The differences in spatial distribution and driving factors of protected rivers (PRs) between the two countries reflected their differences in conservation objectives, ideology, and governance system of protected areas.