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Changes in land use and land cover are known to impact ecosystem services and functions. In this study, land use characteristics were combined with global and China‐specific ecosystem coefficients to quantify land‐use and ecosystem service changes in Charchan Oasis. Results indicated that: (i) the total values of ecosystem services in Charchan Oasis were increased 8·4 M$ from 1972 to 2013; (ii) the aggregated ecosystem service values for water bodies, grasslands, forest lands, and barren lands were 98·90% of the total value for all land types; (iii) waste treatment, soil formation, biodiversity protection, and water supply were ecological functions with the highest service values, contributing approximately 65% of the total service values; and (iv) ecosystem service values estimated in this study were inelastic with respect to the value coefficients, therefore, the estimation results were believable. Copyright © 2016 John Wiley & Sons, Ltd.

Satellite data and the published coefficients about the world's and China's ecosystem were used to analyze the effects of land-use changes on the ecosystem service in the Yanqi Basin. Both economic developments and arid, fragile ecosystems have strongly affected the land use. A sensitivity analysis determined the effect of manipulating the coefficients on the estimated values. Results indicated that (1) the total value of ecosystem services in the Yanqi Basin were 9,374.66, 10,450.52, 9,964.20, and 9,8707.77 million Yuan in 1990, 2000, 2005, and 2011, respectively. The net increase in ecosystem service values were about 496.11 million Yuan within 1990-2011; (2) The aggregated ecosystem service values of water body, wetlands, grasslands, and croplands were about 99.25 % of the total value; (3) Waste treatment and soil formation were the top two ecological functions with high service values and contributing about 61.70 % of the total service values; and (4) Ecosystem service values estimated in this study were inelastic with respect to the value coefficients; therefore, the estimation was robust in spite of uncertainties on the value coefficients. A reasonable land-use plan should be based on rigorous environmental impact analyses for maintaining stability and sustainable development of the Yanqi Basin.

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Bosten Lake, a typical rump lake in an oasis in northwest China, was chosen to evaluate the distribution, sources, pollution status, and potential ecological risk of heavy metals. Sediment samples were collected from the lake, and results showed that the values of the eight heavy metals all fell within the Second Soil National Standard, while the average and maximum values of the metals were higher than the background values of the study. Multivariate statistical analysis showed that sediment concentrations of Cd, Pb, Hg, and Zn were mainly influenced by man sources. In comparison, Cu, Ni, Cr, and As were primarily natural in origin. Enrichment factor analysis (EF) and the geo-accumulation index evaluation method (I geo) showed that Cd, Hg, and Pb fell under low and partial serious pollution levels, while Zn, As, Cr, Ni, and Cu mainly were characterized under no pollution and low pollution levels. The potential ecological hazards index (RI) showed that among the eight heavy metals, Pb, Hg, and Cd posed the highest potential ecological risk, with potential ecological hazards indices (RI) of 29.06, 27.71, and 21.54 %, respectively. These findings demonstrated that recent economic development in the area of the basin has led to heavy metal accumulation in the surface sediments of the lake.

Ecosystem service and human activity assessment are essential for effective natural resources allocation; however, these were seldom researched in arid region. This study used the theory proposed by Millennium Ecosystem Assessment to analyse ecosystem services provided by the floodplain forest in the lower reaches of the Tarim River. Results showed the following: (a) In the research area, the ecosystem service values of approximately US$216.78 × 108 occurring from 1972 to 2015 showed a decreasing trend; (b) the total ecosystem service values for floodplain forest and water area for all land use and land cover types accounted for 87.43% of the total value in the research area, and water supply, biodiversity protection, and waste treatment accounted for 55% of the total function values—these were the highest service values; (c) this research showed that the estimated ecosystem service values of research area were inelastic to value coefficients. This study showed that future work should allow land use and Ecological Water Conveyance Project to follow with rigorous environmental impact analyses. These analyses will be crucial to maintain the stability and sustainable development in the lower reaches of the Tarim River and also can provide references for research in the arid regions of Northwest China and Central Asia.

Urban green space (UGS) is crucial to the healthy development of urban residents. However, UGS that is accessible can benefit residents to an even greater degree. Based on the two-step floating catchment area model (2SFCA) and the location quotient (LQ), we analyzed the changes from 1999 to 2019 in UGS walking accessibility and equity in built-up areas of Urumqi at different administrative levels, and how UGS policy affects the improvement of accessibility. The results showed that UGS accessibility and equity are not evenly distributed at different administrative levels and UGS categories. Although the overall UGS accessibility and equity has improved with policy implementation, these changes are caused by metro-level UGS construction in urban fringe areas. The improvement in UGS accessibility at the neighborhood level in densely populated areas is neglected, which leads to a mismatch between UGS construction and population distribution. In addition, the accessibility of UGS is also limited by geographical location, population density, road distribution, and water shortage in arid metropolitan Urumqi. Our research results provide a theoretical basis for Urumqi and other cities in the optimization of UGS structure and the realization of social equity.