| Qinling Mountains is the main water conservation area and ecological protection area in our country.The value of ecology and environmental protection is extremely high,and it has a far-reaching and significant impact on the sustainable development of China’s economy.In order to speed up the construction of the basic framework of the national ecological security pattern of"two screens and three belts",the Qinling-Dabie Mountain ecological barrier will be established,and the mutual promotion of ecological protection and economic development will be realized.This article is based on the Qin Mountains and uses remote sensing,meteorology,soil and other data as the basis to quantitatively evaluate the habitat quality,soil conservation,water production and water quality purification in the study area in 1980,2000and 2018,and analyze the results of Spatio-temporal change characteristics.Finally,the correlation analysis method is used to calculate the balance and synergy between different ecosystem services and the difference in time and space changes,and then the cold and hot areas of the ecosystem services in the study area are divided and judged in order to provide decision support for regional natural resource utilization and management.The main conclusions are as follows:(1)The habitat quality of the study area showed an overall upward trend from 1980 to2018.The habitat quality of the three phases was 0.758,0.796 and 0.792,growth rate of about5%.The habitat quality of Nanzheng County and Hantai District are the lowest in the entire study area but Chang’an and Ningshan County are the highest.The habitat quality of the southwestern part of the study area is lower,and the decline is more obvious.The habitat quality of the central part is relatively low.The counties with higher and obvious growth rates are also mainly distributed in the middle and northeast of the study area.The area with the highest habitat quality value in the third phase of the study area is the Jialing River,and the Nanluo River has the lowest habitat quality.(2)The total soil and water conservation in the study area showed a decreasing trend from 1980 to 2018.The three stages of soil and water conservation were 609.64×10~7tons,516.93×10~7tons and 390.41×10~7tons,respectively.Lintong and Qishan counties have the highest average soil and water conservation in the study area,while Ningshan County and Zhashui County are the counties with the lowest water and soil conservation in the study area.The soil and water conservation in the Danjiang River Basin declined the most during the study years,and the change in the soil and water conservation in the Jialing River Basin was the smallest.Woodland type has the strongest soil and water conservation ability,followed by grassland and cultivated land.(3)The water production in the study area showed an overall downward trend from 1980to 2018.The total water production of the three phases was 346.55×108m~3,233.83×108m~3and 245.87×108m~3,respectively.Shangnan and Tongguan counties have the highest water production per unit area,and Lueyang and Zhashui counties have the lowest water production per unit area;the largest drop in water production per unit area is in Hantai District and Lueyang County,Shangnan county has the smallest decline.The water production in the west has increased significantly,while the south has shown a downward trend.The water production per unit area of the Han River Basin declined the most during the study year,while the Nanluo River declined the least.The woodland type has the highest water production,followed by cultivated land and grassland.(4)In the study area,the highest purification capacity of water is forest land,followed by grassland,arable land,water and construction land.During the study years,the retention of nitrogen and phosphorus decreased,and the output of nitrogen and phosphorus also decreased,but the decline in the output and retention of nitrogen were greater than the decline in the output of phosphorus.Nanluo River had the strongest ability to purify nitrogen,Han River had the strongest ability to purify phosphorus,and Dan River had the largest decrease in water quality during the study years.The highest nitrogen retention and output per unit area were for construction land,and the highest phosphorus retention and output was for cultivated land,which indicated that construction land and cultivated land were the main sources of non-point source pollution in the study area due to human activities.(5)From 1980 to 2018,the relationship between the four ecosystem services in the study area was basically consistent.Habitat quality and soil conservation and water production showed a weaker trade-off relationshipand a strong synergistic relationship with water quality purification.Soil conservation and water productionshoweda strong synergistic relationship and a weak synergistic relationship with water quality purification,water production and water quality purification showed a strong synergistic relationship.The correlation coefficient between habitat quality and water production changed the most during the study years,while the correlation coefficient between habitat quality and water and soil conservation remained basically unchanged.(6)According to the distribution map of the cold and hot spots in the three phases of the study area,4 types of service areas accounted for the smallest area,2 types of service are as accounted for the largest area.In 1980,the hot spots of ecosystem services in Qin Mountains were mainly distributed in the southwest and southeast,and the cold spots in the central and eastern regions were relatively concentrated;In 2000,the hot spots were mainly in the southeast and the cold spots were mainly in the north-central;In 2018,the hot spots were concentrated in the northwest,Central South and east of the study area,and the distribution range of cold spots was consistent with that in 2000.The hot spot area of Jialing River Basin has a significant growth,while the growth rate of Hanjiang River Basin is the smallest. |
