Abstract:Increasing anthropogenic activities have significantly altered ecosystems in arid oasis regions. Estimating the impact on a wide range of ecosystem services is important for decision making and the sustainable development of these regions. This study analyzed time-series Landsat data to determine the influences of oasis land-use changes on the ecosystem services in the Kashgar region in Northwest China. The following results were found. The total value of the ecosystem services in the Kashgar region were approximately $10, 845.3, $11,218.6, $10,291.7, and $10,127.3 million in 1986, 1996, 2005, and 2015, respectively. The water supply, waste treatment, biodiversity protection, and recreation and cultural services were the four ecosystem services with the highest service value, contributing 77.05% of the total ecosystem services. The combined contribution rate of food production and raw material value was only about 4.02%, relatively small. The sensitivity analysis indicated that the estimated total ecosystem service value (ESV) for this study area was relatively inelastic with respect to the value coefficients. The findings of this study will be crucial for maintaining the stability and sustainable development of the oasis region, where socio-economic development and the integrity of the natural ecosystem complement each other. Furthermore, the results provide a scientific basis for decision makers in land use management, and provide a reference for researchers in the Northwest China.

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The growing urbanization of oasis cities in arid and semi-arid regions of Northwest China has an adverse influence on the fragile local ecological system. Therefore, improved understanding of the coupling and coordination between urban expansion (UE) and ecosystem services value (ESv) is critical to long term sustainable development. Here, we study the urbanization trend of a typical oasis city of Northwest China (Kashgar) using Landsat TM/ETM+/OLI imagery from 1990 to 2015. Land use types are classified and the spatio-temporal features of UE are analyzed; ESv of each land use types and the ecosystem services function (ESf) are determined; the driving factors of UE and the spatio-temporal change of ESv are analyzed; and the coupling and coordination relationship between UE and ESv is quantitatively determined. Results show that: (1) The land use structure has changed significantly between 1990 and 2015, with construction land (40.51 km2) showing the highest growth and farmland (28.42 km2). (2) UE values during 2000–2005 (16.65 km2) and 2010–2015 (21.09 km2) are relatively large, and during 1990–2015, the city extended from the center to the outskirts at a dynamic growth rate of 13.17% and a comprehensive expansion index of 1.54‰. (3) The total ESv was reduced by CNY 35.76 million (USD ~ 5.26 million), ranked from high to low as: waste treatment (CNY 9.94 million, USD ~1.46 million), water source conservation (CNY 7.95 million, USD ~ 1.17 million), soil formation (CNY 4.60 million, USD ~ 0.68 million), biodiversity protection (CNY 3.37 million, USD ~ 0.5 million), climate regulation (CNY 3.15 million, USD ~ 0.46 million), food production (CNY 2.83 million, USD ~ 0.42 million), gas regulation (CNY 1.96 million, USD ~ 0.29 million), entertainment and leisure (CNY 1.26 million, USD ~ 0.19 million), and raw materials (CNY 0.68 million, USD ~ 0.1 million). (4) The coupling degree between UE and ESv is relatively small (<0.5), though this value has increased yearly. The coordination degree between UE and ESv is relatively low, indicating that UE already poses a serious danger to the ecological environment. (5) The rapid growth of the population and economy and government policies are the main driving factors of intensive UE. Increasing climatic factors such as precipitation, temperature, and runoff impact ESv in some positive ways whereas UE leads to a reduction of ESv. Our results here can help to guide long-term sustainable development of arid regions, reasonable urban planning of oasis cities, and protection of the local ecological environment.

In this study, we used long time series Landsat data and ecosystem services coefficients for global and Chinese ecosystems during 1978–2018 to estimate the influences of land-use change on ecosystem services (ES) in Kaidu–Kongque River Basin (KKRB), where both socioeconomic progress and the arid, fragile natural environment have considerable affected land-use change. The results showed that (1) the total value of ES in the KKRB was about USD 8111.5, 7995.31, 8275.74, 8131.91, and 8016.38 million in 1978, 1988, 1998, 2008, and 2018, respectively. The net ecosystem service value (ESV) loss was about USD 116.19 million for 1978–1988, the net ESV profit was about USD 280.43 million for 1988–1998, and the net ESV loss was about USD 259.36 million for 1998–2018. (2) Water supply and waste treatment function were the top two ecological functions with high service value; their combined contribution rate was 59.3%, indicating that the regulating service function in this study area is higher than the provision services function. (3) The high to low ranking for each ecosystem function based on their contribution rate to overall ES value was water supply > waste treatment > climate regulation > biodiversity protection > recreation and culture > soil formation > gas regulation > food production > raw material. These results are significant for the continuation of the integrity and sustainability of the mountain–oasis–desert region ecosystem, where socioeconomic progress and the fragile characteristics of the natural ecosystem complement each other. The results of this study provide scientific evidence for governmental decision makers and local residents and offer a reference for environmental researchers in northwest China.