Abstract:

Bailongjiang watershed in Gansu belongs to the upper reaches of Yangtze River water conservation area and the environment fragile area with frequent landslides and debris flow. Recently, the high-intensive human activities have caused the deterioration of natural systems. Therefore, it is of great significance to study the changes of ecosystem services and its trade-offs. In this paper, the spatial and temporal changes, spatial aggregation and the trade-offs/synergies between ecosystem services from 1990 to 2014 were quantitatively analyzed via the ecosystem service change index, spatial autocorrelation and correlation coefficient. The results showed that the ESCI ranges of the four typical ecosystem services types, namely, water yield, carbon storage, soil conservation and crop production were different from 1990 to 2014 with the difference of spatial distribution. There are spatial autocorrelation in four typical ecosystem services with obvious clustering characteristics. The cluster character and agglomeration of positive correlation of the local scale is strong, the agglomeration of the negative correlation type is low and scattered, and the spatial heterogeneity is significant. There is a negative correlation trade-offs between the two provisioning services (water yield and crop production), and positive correlation synergies between the two regulating services (carbon stocks and soil conservation). The relationships between the provisioning and regulating services have both trade-offs and synergies. There were both strong positive correlation synergies between water yield and soil conservation, and between water yield and carbon storage, and there were weak negative correlation trade-offs between soil conservation and crop production. As for the numerical relation, the trade-offs/synergies of ecosystem service changed differently in terms of Moran's I and correlation coefficient. There is significant heterogeneity of trade-offs/synergies between ecosystem services on the spatial pattern.

Key words: ecosystem services, spatiotemporal change, trade-offs/synergies, Bailongjiang Watershed in Gansu