The Muli coal mine is the largest open-cast coal mine in the Qinghai-Tibet Plateau, and it consists of two independent mining sites named Juhugeng and Jiangcang. It has received much attention due to ...the ecological problems caused by rapid expansion in recent years. The objective of this paper was to monitor the mining area and its surrounding land cover over the period 1976–2016 utilizing Landsat images, and the network structure of land cover changes was determined to visualize the relationships and pattern of the mining-induced land cover changes. In addition, the responses of the surrounding landscape pattern were analysed by constructing gradient transects. The results show that the mining area was increasing in size, especially after 2000 (increased by 71.68 km
2
), and this caused shrinkage of the surrounding lands, including alpine meadow wetland (53.44 km
2
), alpine meadow (6.28 km
2
) and water (6.24 km
2
). The network structure of the mining area revealed the changes in lands surrounding the mining area. The impact of mining development on landscape patterns was mainly distributed within a range of 1–6 km. Alpine meadow wetland was most affected in Juhugeng, while alpine meadow was most affected in Jiangcang. The results of this study provide a reference for the ecological assessment and restoration of the Muli coal mine land.
Land-use/land-cover changes （LUCCs） have links to both human and nature inter- actions. China＇s Land-Use/cover Datasets （CLUDs） were updated regularly at 5-year inter- vals from the late 1980s to ...2010, with standard procedures based on Landsat TM／ETM＋ im- ages. A land-use dynamic regionalization method was proposed to analyze major land-use conversions. The spatiotemporal characteristics, differences, and causes of land-use changes at a national scale were then examined. The main findings are summarized as fol- lows. Land-use changes （LUCs） across China indicated a significant variation in spatial and temporal characteristics in the last 20 years （1990-2010）. The area of cropland change de- creased in the south and increased in the north, but the total area remained almost un- changed. The reclaimed cropland was shifted from the northeast to the northwest. The built-up lands expanded rapidly, were mainly distributed in the east, and gradually spread out to central and western China. Woodland decreased first, and then increased, but desert area was the opposite. Grassland continued decreasing. Different spatial patterns of LUC in China were found between the late 20th century and the early 21st century. The original 13 LUC zones were replaced by 15 units with changes of boundaries in some zones. The main spatial characteristics of these changes included （1） an accelerated expansion of built-up land in the Huang-Huai-Hai region, the southeastern coastal areas, the midstream area of the Yangtze River, and the Sichuan Basin; （2） shifted land reclamation in the north from northeast China and eastern Inner Mongolia to the oasis agricultural areas in northwest China; （3） continuous transformation from rain-fed farmlands in northeast China to paddy fields; and （4） effective- ness of the ＂Grain for Green＂ project in the southern agricultural-pastoral ecotones of Inner Mongolia, the Loess Plateau, and southwestern mountainous areas. In the last two decades, although climate change in the north affected the change in cropland, policy regulation and economic driving forces were still the primary causes of LUC across China. During the first decade of the 21st century, the anthropogenic factors that drove variations in land-use pat- terns have shifted the emphasis from one-way land development to both development and conservation. The ＂dynamic regionalization method＂ was used to analyze changes in the spatial patterns of zoning boundaries, the internal characteristics of zones, and the growth and decrease of units. The results revealed ＂the pattern of the change process,＂ namely the process of LUC and regional differences in characteristics at different stages. The growth and decrease of zones during this dynamic LUC zoning, variations in unit boundaries, and the characteristics of change intensities between the former and latter decades were examined. The patterns of alternative transformation between the ＂pattern＂ and ＂process＂ of land use and the causes for changes in different types and different regions of land use were explored.
As the population has increased and the economy has developed in the Qaidam Basin, the demand for food and energy in the basin has increased, and the contradiction between economic development and ...ecological protection is gradually becoming prominent. In this study, the eco-environmental quality of the Qaidam Basin from 1986 to 2019 was evaluated and analyzed based on the Modified Remote Sensing Ecological Index (MRSEI) retrieved by the Google Earth Engine (GEE) and meteorological and socioeconomic auxiliary data. The results show that (1) the Qaidam Basin had a lower overall level of eco-environmental quality, with higher eco-environmental quality in the southeastern part of the basin and lower eco-environmental quality in the central and northwestern parts of the basin. (2) During the period of 1986 to 2019, the eco-environmental quality of the Qaidam Basin started to reverse in 2003; it decreased first and then increased, and the overall performance showed an upward trend over the past 34 years. The most obvious changes were in the northwestern, northeastern, southwestern and central parts of the basin. The eco-environmental quality continued to decline in the northwestern and rise in the northeastern and southwestern regions, and in the central part, it decreased first and then plateaued. (3) The eco-environmental quality of the Qaidam Basin was affected by both natural and human factors. From 1986 to 2019, the “warm and wet” climate in the basin promoted the growth of vegetation. Furthermore, the optimization of industrial structures alleviated the pressure of agriculture and livestock and jointly improved the ecological environment in the Qaidam Basin.
Land use and land cover change as the core of coupled human-environment systems has become a potential field of land change science （LCS） in the study of global environmental change. Based on ...remotely sensed data of land use change with a spatial resolution of 1 km × 1 km on national scale among every 5 years, this paper designed a new dynamic regionalization according to the comprehensive characteristics of land use change including regional differentiation, physical, economic, and macro-policy factors as well. Spatial pattern of land use change and its driving forces were investigated in China in the early 21 st century. To sum up, land use change pattern of this period was characterized by rapid changes in the whole country. Over the agricultural zones, e.g., Huang-Huai-Hai Plain, the southeast coastal areas and Sichuan Basin, a great proportion of fine arable land were engrossed owing to considerable expansion of the built-up and residential areas, resulting in decrease of paddy land area in southern China. The development of oasis agriculture in Northwest China and the reclamation in Northeast China led to a slight increase in arable land area in northern China. Due to the ＂Grain for Green＂ policy, forest area was significantly increased in the middle and western developing regions, where the vegetation coverage was substantially enlarged, likewise. This paper argued the main driving forces as the implementation of the strategy on land use and regional development, such as policies of ＂Western Development＂, ＂Revitalization of Northeast＂, coupled with rapidly economic development during this period.
•The mining area and the surrounding land cover changes on the southern slope of Qilian Mountains in the northeast of Qinghai Tibet Plateau.•Estimating the surrounding ecosystem services variation ...and loss due to the spatial adjacency effect of the mining areas.•Trade-off analysis between mining benefits and loss of ecosystem service values in fragile Qinghai-Tibet Plateau.
Surface mining can destroy the ecosystems and result in the loss of the service values of the surrounding ecosystems through direct occupation and indirect impact on the neighboring ecosystems. In the Qinghai-Tibet Plateau (QTP), where the ecological system is fragile and sensitive, the mining development has led to a series of ecological and environmental issues and social controversies and aroused much attention in the recent years. This paper selected six typical open-pit coal mines in the Southern Slope of Qilian Mountain (SSQM) in the northern QTP to monitor the changes of mining extent and the surrounding land cover from 1975 to 2016 and estimate the surrounding ecosystem service value (ESV) changes by considering spatial adjacency effects. A trade-off analysis is finally employed to compare the mining benefit and ESV loss associated with the development of mining areas. Results showed that the mining areas increased in six regions, especially after year 2000, which resulted in the decline of wetland, meadow and grassland areas. The regional ecosystem service values decreased with the expansion of mining areas, and the spatial adjacency effect has accelerated with the loss of ecosystem service value, especially the service value of wetlands and hydrological regulation function. The larger the mining extent and unit area value of the surrounding ecosystem services, the greater the ESV loss due to mining activities, and the dispersive and disorderly exploitation of mining areas will also result in a rapid increase in ESV loss, while mining development in areas with lower ESV is more beneficial. The results of this paper are instructive to the development and planning of mineral resources in Qinghai-Tibet Plateau and other ecologically fragile areas.
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New conversion from grassland to cropland was effectively curbed with the implementation of the Grain-to-Green Program (GTGP) in northern China from 1999 to 2010. However, the phenomenon of grassland ...reclamation has significantly increased since 2010. Here, the latest trend of conversion from grassland to cropland was evaluated using a Landsat dataset from 2010 and 2015 in the Mu Us Desert (MUD) of northern China. An object-based approach was chosen to classify grassland and farmland information, and the classification accuracy was 98.33% based on 120 cropland verification points, which were obtained through available Google Earth and field survey data. The area of grassland reclamation increased by 411.29 km
2
from 2010 to 2015 and was mainly distributed in the southeastern and southwestern parts of the MUD, accounting for 9.78% of the total cropland area in 2015. There were two ways to reclaim grassland, including herdsmen cultivating grasslands on their own pastures and grassland reclamation projects implemented by enterprises under the direction of local governments. Exposed cultivated land is more susceptible to wind erosion and eventually leads to decreasing agricultural productivity and desertification. Therefore, strategies to reduce wind erosion on reclaimed grassland in the study area should be implemented as soon as possible, including several alternative cultivation systems and ridge tillage. If conditions permit, conservation tillage should be changed in the MUD.
Alxa League of Inner Mongolia Autonomous Region is a concentrated desert distribution area in China, and the latest desertification process and its driving mechanism under the comprehensive influence ...of the extreme dry climate and intense human activities has attracted much attention. Landsat data, including ETM+ images obtained in 2000, TM images obtained in 2010, and OLI images obtained in 2020, were used to extract three periods of desertification land information using the classification and regression tree (CART) decision tree classification method in Alxa League. The spatio-temporal variation characteristics of desertification land were analyzed by combining the transfer matrix and barycenter migration model; the effects of climate change and human activities on regional desertification evolution were separated and recombined using the multiple regression residual analysis method and by considering the influence of non-zonal factors. The results showed that from 2000 to 2020, the overall area of desertification land in Alxa League was reduced, the desertification degree was alleviated, the desertification trend was reversed, and the desertification degree in the northern part of the region was more serious than in the southern part. The barycenter of the slight, moderate, and severe desertification land migrated to the southeast, whereas the serious desertification land’s barycenter migrated to the northwest in the period of 2000–2010; however, all of them hardly moved from 2010 to 2020. The degree of desertification reversal in the south was more significant than in the north. Regional desertification reversal was mainly influenced by the combination of human activities and climate change, and the area accounted for 61.5%; meanwhile, the localized desertification development was mainly affected by human activities and accounted for 76.8%.
Since the 1980s, with rapid economic development and increased attention given to ecological protection, China has launched a series of ecological-restoration programs to restore the local ...environment through afforestation and natural forest protection. The evaluation of vegetation restoration is an important part of evaluating the effectiveness of ecological restoration. The Loess Plateau is an area where ecological problems are concentrated, and it is a key area of ecological construction in China. This paper takes the Loess Plateau as the research area, using remote sensing and geographic information technology combined with ecosystem structural changes and an improved residual model to study vegetation restoration. The following main conclusions were drawn: (1) From 1990 to 2000, the farmland area increased by 3084.81 km2, resulting in the encroachment of a large area of grassland and shrubland. (2) With the implementation of ecological engineering, the area of returning farmland to forest and grassland reached 18,001.88 km2; in this period, the NDVI of vegetation increased rapidly, and the area that increased comprised 91.90% of the total area, of which the area of significant increase reached 65.78%. The quality of vegetation was restored to a great extent, and ecological engineering played a major role in this stage. (3) Under the background of large-scale implementation of ecological restoration, the urban area of the Loess Plateau continues to expand.
The Mu Us Sandy Land (MUSL) has undergone climate changes and shifts in human activities driven by a series of ecological restoration projects in recent decades. We analyze the spatiotemporal ...dynamics of vegetation in this region using the satellite-retrieved normalized difference vegetation index (NDVI) from the Global Inventory Modeling and Mapping Studies (GIMMS) and Moderate Resolution Imaging and Spectroradiometer (MODIS) datasets during the past 33 years. The results show that (1) the vegetation in 53.46% of the MUSL exhibited an upward trend, and 34.45% of the area displayed a large increase, mainly in the eastern part of the MUSL region, including most of Shenmu County, Yuyang District, Hengshan County, and Jingbian County. (2) By the end of 2014, the rapid increase in vegetation encompassed 16.85% of the total area of the study region due to the construction of ecological engineering projects. (3) Based on the residual regression method, the area of positive effects accounted for 55.07% of the total area, and the vegetation in the study area was positively affected by human activities. Our study suggests that these multiple ecological restoration programs contributed to the accelerated greening trend in the MUSL region and highlights the importance of human intervention in regional vegetation growth under climate change conditions.
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•Obtained a time-series data set of aeolian desertification.•Application of a quantitative method (Path Analysis Model) for identifying the cause of aeoian desertification.•A network ...of intercorrelations of human activities and climate in determining rarea is identified.•The influence of the interaction between human activities and climate change on aeolian desertification is obvious.
As is a land degradation process caused by an uncoordinated Human-Earth relationship, aeolian desertification has threatened the safety of eco-environmental and the development of social economy in northern China. Although most studies focus on the causes or driving forces of aeolian desertification with climatic and anthropogenic factors, lack of the impact analysis of the relationship between climate change and human activities, the driving mechanism still remain unclear. In the present study, first the spatial patterns of aeolian desertification land from 1975 to 2015 were obtained by visual interpretation in Mu Us Sandy Land with satellite data. Then, climatic (i.e., temperature, precipitation, relative humidity, and wind speed), and socio-economic data (i.e., population density, livestock, woodland area, and farmland area) were combined with the aeolian desertification pattern to investigate the direct and indirect effects of climate change and human activities on the aeolian desertification via the path analysis model. The results are as follows: (1) During the past 4 decades, the aeolian desertification in Mu Us Sandy Land showed a trend of “violent development-slow reversal” with extremely severe aeolian desertified land as the main representative. The aeolian desertified land area reached 57,778.32 km2 by 2015. (2) Overall, human activities accounted for 50.96% of the relative influence on aeolian desertification land net growth rate, followed by climate 49.04%, with the temperature, livestock, and population as dominate factors. (3) Path analysis identified a network of inter-correlations of human activities and climate in determining aeolian desertification land net growth rate. (4) The direct correlation of aeolian desertification land net growth rate with human activities was significantly weakened if removing the effects of climate. These results reveal the relative importance of human activities and climate and their complex interconnections in regulating aeolian desertification process.
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