The spatial-temporal pattern of hotspots and coldspots of ecosystem services at the watershed scale

There is a great significance for ecological protection planning to identify the hotspots and coldspots of ecosystem services and to research their spatial-temporal patterns. Nowadays,direct classification is used in identification of the hotspots and coldspots of ecosystem services,but there is no comprehensive research on the characteristics of their spatial relationships. Taking the Yanhe River basin as an example,comprehensive multi-source data integration was used to simulate the changes in the spatial-temporal patterns of hotspots and coldspots of four ecosystem services( soil conservation,vegetation carbon sequestration,water yield,and flood regulation). The main conclusions of this paper are as follows: ①During 2001-2012,the soil conservation service in the Yanhe River basin was higher in the lower reaches than in the upper reaches,while its growth in the middle reaches was rapid. The ecosystem services of vegetation carbon sequestration and flood regulation were strong in the southern region of the basin and were rising in the middle and lower reaches. The distribution pattern of water yield fit a model of "high value in north and south,and low value in middle",which shows a downward trend in the upper reaches of the basin and an upward trend in the middle and lower reaches. ② The hotspots of ecosystem services are mainly distributed in the south of the middle and lower reaches of Yanhe,while the coldspots are mainly distributed in the upper reaches of Yanhe. The four ecosystem services were all strong in the south of the middle and lower reaches of the Yanhe River. The area with the highest efficiency of ecosystem service protection was the upper reaches of Yanhe. ③ The ecosystem services of soil conservation,vegetation carbon sequestration,and flood regulation were better in forest lands in the Yanhe River basin than they were in other land-use types,while the water yield service was weaker.The wetlands were the opposite. Soil conservation and vegetation carbon sequestration were relatively better in grasslands than in other land-use types. The four services were stronger in cultivated land than in bare land,and the four services were much weaker in bare land than in other land-use types. The land-use type with the highest conservation efficiencies of soil conservation,vegetation carbon sequestration,and flood regulation was wetlands,and the land-use type with the highest conservation efficiency of water yield was forest lands. The results of th