Abstract:

Hotspot analysis can be used to identify spatial clusters of high (or low) value to ecosystem services (ES) in a study area, helping to further explore study areas with a relatively high or low value of each ES. As one application, this is of great significance to the protection and restoration of the ecological environment in coalfields. In this study, we collected remote sensing data, meteorological data, and soil data (as well as data of other types) from coalfields in Shanxi Province, China from 1986 and 2015 and estimated the soil conservation and water yield using the integrated valuation of ES and trade-offs (InVEST) model, the vegetation net primary productivity based on the Carnegie-Ames-Stanford approach, and the sand fixation service based on the revised wind erosion equation. Furthermore, we identified the spatial distribution of hotspots (and coldspots) of ES using the Getis-Ord G_i^* tool of ArcGIS. The results demonstrated the following: (1) From the perspective of individual ES, the overall spatial distribution of hotspots for soil conservation service did not significantly change from 1986 to 2015, whereas the coldspots of the soil conservation service were mainly transferred from Qinshui Coalfield and Huoxi Coalfield to the Hedong Coalfield. The hotspots of water yield also increased significantly in the eastern part of Qinshui Coalfield, whereas the coldspots of water yield increased mainly in the southern part of Hedong Coalfield. Overall, the hotspots of vegetation production service moved from the south to the northeast of Heqinshui Coalfield, whereas the coldspots of vegetation production service mainly moved from Xishan Coalfield and Qinshui Coalfield to Hedong Coalfield and the Datong Coalfield. The hotspots of sand fixation service transferred from the northwest to the southeast as a whole, and the coldspots of sand fixation service mainly transferred from Qinshui Coalfield to Huoxi Coalfield and the Hedong Coalfield. (2) From the perspective of multiple ES, from 1986 to 2015, Qinshui Coalfield in the southeastern part of the study area, which belongs to the key ecosystem service function supply area, was a hotspot of multiple ecosystem services. Hedong Coalfield and Huoxi Coalfield were also coldspots of multiple ES. (3) From the perspective of different land use types, the hotspots of water yield and vegetation production of cultivated land accounted for a relatively high proportion, meaning their level of service was stronger than those of other services. The hotspots of soil conservation service for forest land and grassland also accounted for the largest proportion of hotspots, meaning the level of soil conservation was high, whereas the water yield of construction land was relatively high. The spatial distribution of ES in coalfields and their changes in terms of hotspots and coldspots were closely related to land use. Accordingly, maintaining a good coupling state between land use and ES will be helpful to provide a scientific basis for regional ecological reconstruction and the sustainable development of coalfields.

Key words: coalfields, ecosystem services, hot spot analysis, land use, spatial pattern