# Spatio-Temporal Changes in Ecosystem Quality across the Belt and Road Region
## 4 Results
### Temporal Changes in EQI  
The differences in the continuous EQI values (symbolized by \(\Delta\)EQI) from year 2016 to 2020 were calculated to identify the regions where the EQIs significantly changed according to the criterion of the \"Regional ecological quality evaluation method\" published by the Ministry of Ecology and Environment of the People's Republic of China [32]. Finally, three significance levels were determined (Figure 7) according to the changed EQI value ranges: significantly increased EQI with \(\Delta\)EQI \(>\) 0.05 (in green), no significant EQI changes with \(-0.05<\Delta\)EQI \(\leq\) 0.05 (in yellow) and significantly decreased EQI with \(\Delta\)EQI \(\leq-0.05\) (in red).  
Figure 8 shows the percentages of EQI changes in the 10 eco-geographical zones of the entire study area from 2016 to 2020. Combined with Figure 7, it can be concluded that regions with significantly decreased EQIs occupied 0.45% of the total area, mostly distributed north and central of Central Asia, southeast and central of Russia, southeast and southwest of Australia, and north of West Asia. Central Asia suffered the most serious deterioration in ecosystem quality, accounting for 0.15% of the total study area. This is in accordance with the review of ecological environment patterns across the B&R region performed by [PERSON] et al., which indicated that vegetation ecological factors will cause obvious zonal and gradient reduction on a scale of a few decades to a hundred years [11]. Generally, Central Asia has a temperate continental climate with scarce precipitation and widespread desert grassland, which makes the ecosystem quality of Central Asia poorer. However, regions with a significantly increased EQI occupied 0.22% and the regions with no significant EQI changes occupied 99.33% of the entire study area, which indicates that most of the B&R regions showed no significant change from the years 2016 to 2020.  
Figure 5: Proportions of EQI levels in each eco-geographical zone in 2016 and 2020.  
Figure 6: Percentages of EQI levels in the six ecosystem types in 2016 and 2020.  
Figure 9 shows that the percentages of each ecosystem type area with different EQIs changed from 2016 to 2020 in the four eco-geographical zones, which had significantly decreased EQIs. Generally, the total significantly decreased EQI areas in certain eco-geographical zones are the sum of the significantly decreased EQI areas in each ecosystem type. In the four eco-geographical zones, the cultivated land and grassland experienced significantly decreased EQIs. The forest ecosystem type suffering from significantly decreased EQIs was distributed in Russia and Australia. The shrubland ecosystem had a significantly decreased EQI distributed in Russia. Overall, the cultivated land in Central Asia suffered the most serious deterioration in ecosystem quality in the study period. This is in accordance with the articulate ecosystem in Central Asia that was found to be aggravated by [PERSON] et al. 2022, who pointed out that the interplay between anthropogenic forces and the natural variability in the Interdecadal Pacific Oscillation exacerbated the agricultural drought in Central Asia for nearly 30 years [33].  
Figure 8: Percentages of EQI changes in the 10 eco-geographical zones of the entire study area from 2016 to 2020.  
Figure 7: Regions with no significant EQI changes (in yellow), significantly increased EQI (in green), and significantly decreased EQI (in red) from 2016 to 2020.