A new remote-sensing-based indicator for integrating quantity and quality attributes to assess the dynamics of ecosystem assets

Ecological benefits provided by ecosystem assets play an important role in improving human wellbeing. However, there are few feasible methods to combine data on the quantity and quality of ecosystem assets to describe their state and trend. Here, we developed a new remote-sensing-based indicator by synthesizing ecosystem asset quantity and quality data for effective assessment at a regional or national scale. The new indicator includes a typological ecosystem asset index (TEAI) (e.g., forest ecosystem asset index) and an integrated ecosystem asset index (IEAI). The TEAI and IEAI can be used to assess the state and trend of a specific ecosystem or set of regional ecosystems, respectively. We applied the new indicator in the context of ecological protection policy in the Three-Rivers Source Region (TRSR), a region known as the ‘Chinese water tower’. From 2000 to 2015, the IEAI increased by 4.02% due to an increase in the ecosystem asset area (0.2%) and the ecosystem asset quality (0.66% and 0.02% increases in excellent and good level ecosystem assets, respectively). The implementation of ecological protection and ecological restoration programs was the main direct driver of regional ecological asset improvement. Our results suggest the new indicator is feasible for quickly and accurately evaluating the state and trend of ecosystem assets and can be used to guide ecosystem management at a large regional scale.