As an important ecological barrier in Southwest China, the Qingjiang river basin plays a vital role in shaping the mountainous terrain. This paper analyzes the Ecosystem Services Value (ESV) using a series of methods based on the data of changes in land use from 2000 to 2015 and the statistical yearbook. The changes in land use between 2000 and 2015 were dominated by forest land, which accounted for 60.63% of the total area, followed by arable landwhich accounted for about 22.26%, while

more »

... d and other land use contribution rates were the lowest, accounting for only about 17.11%. Environmental changes and economic development were uneven. The regional comprehensive strength of En'shi City, Changyang County, and Yidu City were among the highest, while Badong County, Hefeng County, and Wufeng County were among the lowest in the area under study. In addition, the ESV in 2035 was estimated to be 1.56 billion dollars, a decrease of 27.64% when compared with the year 2000. The ESV of Yidu City, Lichuan City, Jianshi County, and Hefeng County grew faster, at the rates of 94.76%, 65.12%, 96.96%, and 92.38%, respectively. However, the ESV of En'shi City, Badong County, Wufeng County and Xuan'en County showed a downward trend, at the rates of −32.53%, −487.80%, −368.07%, and −181.52%, respectively. Sustainability 2017, 9, 2356 2 of 17 and the ESV calculation proposed by is among the most influential. However, these studies did not consider the spatial heterogeneity due to the spatial variation of land use change. At the same time, there has been a paucity of research on the classification of regional ecological systems, apart from such cases as that by Li et al. [16], who analyzed the effect of ecological vulnerability and sensitivity in the ESV of Shiyang river basin in Northwest China. In addition, current studies on spatial and temporal variations of ESV have not fully explored the impact of the coupled human-environment impact on the ESV [17]. The watershed ecosystem provides a variety of services: it provides human beings with clean water; helps irrigate farmland; maintains biodiversity; and promotes economic development with hydro-electric power. However, with the acceleration of industrialization and urbanization, the basin suffers from vegetation deterioration, water loss, expansion of erosion areas, serious degradation of ES functions, and adds to the intense dilemma between economic development and environmental protection [18] . Meanwhile, the urgency for coordination between maintaining basin integrity and cross-regional environmental management is increasing [19] . The watershed ecosystem is a huge compound ES made up of social, economic and natural elements [20] . Due to the regional distribution differences in the river basin, the subsystems differ in the size, shape, number, and type, which affect the energy flow, materials conveyance, and species change in the basin [21] . The watershed ecosystem is maintained through the cycling process of water, carbon, oxygen, nitrogen, and other substances, of which the water resource is the key element in retaining the health of the entire ecosystem and providing for the sustainable development of social economy. Since most ESVs cannot be reflected in the conventional commodity market, it "weighs" less or attracts less attention when making social development decisions. If the value can be quantified, it can make people have a full understanding of the status and role of the watershed ecosystem in supporting economic development, maintaining a healthy ecosystem, and improving human well-being [22] . This awareness is also conducive to helping decision-makers seek reasonable methods of basin resources allocation and ecosystem management [23] . The quantitative assessment of ecosystem services is an important and scientific basis for formulating the ecological compensation mechanism and implementing ecological restoration. The ecological pollution in the Qingjiang river basin not only restricts economic development, but also produces a negative effect on the ecological safety and economy of the middle and lower reaches of the Qingjiang river basin. From March 2016 to early March 2017, our research team investigated the middle and lower reaches of the Qingjiang river basin four times via interviews, as well as online and offline questionnaires. The following facts were revealed: