Table of Content

15 April 2024, Volume 41 Issue 4 Previous Issue   

Weather and Climate

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Prediction of the standardized precipitation evapotranspiration index in the Xinjiang region using the EMD-GWO-LSTM model XU Chaojie, DOU Yan, MENG Qilin 2024, 41 (4):  527-539.  doi: 10.13866/j.azr.2024.04.01 Abstract ( 11 )   HTML ( 2 )   PDF (10705KB) ( 3 )   Drought prediction has always been a major challenge in the field of drought research. Improving the accuracy of drought prediction is the key to solving the drought problem. The standardized precipitation evapotranspiration index (SPEI) was calculated on the basis of the monthly precipitation and average temperature data from 34 meteorological stations in Xinjiang from 1961 to 2019. Dry and wet changes in the Xinjiang region were analyzed. An empirical mode decomposition (EMD)-Gray Wolf Optimizer (GWO)-long short-term memory network is proposed. A combination prediction model based on the data decomposition of LSTM was used to forecast the drought, and the performance of the model was evaluated. The results were as follows: (1) the drought periodicity was stable and the periodicity was long. (2) EMD can effectively optimize the stationarity of data, GWO can optimize the parameters of the prediction model, and the prediction accuracy of the combination model is significantly higher than that of the single prediction model. (3) The accuracy of the results of the four prediction models in descending order was as follows: EMD-GWO-LSTM, GWO-LSTM, GWO-support vector regression (SVR), and LSTM (goodness of fit: 0.972, 0.939, 0.862, 0.830, respectively). The prediction accuracy of the EMD-GWO-LSTM combination prediction model was higher than that of the other three prediction models. The EMD-GWO-LSTM combination prediction model can effectively improve the accuracy of meteorological drought prediction and provide a novel approach for meteorological drought forecasting and drought mitigation in Xinjiang. Figures and Tables | References | Related Articles | Metrics

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Performance evaluation of three daily precipitation products in the upper reaches of the Ili River YIN Ruiqi, LI Qiongfang, CHEN Qihui, ZHANG Jingfang, ZHANG Wei, LIN Yongquan, FANG Kaiyue 2024, 41 (4):  540-549.  doi: 10.13866/j.azr.2024.04.02 Abstract ( 7 )   HTML ( 2 )   PDF (3821KB) ( 2 )   The topographic conditions of the bell in the upper reaches of the Ili River lead to an extremely uneven spatial distribution of precipitation, and it is difficult for limited observation stations to truly determine the spatial and temporal changes in daily precipitation. Therefore, it is necessary to assess the applicability of different precipitation products in the upper reaches of the Ili River. On the basis of seven statistical indicators and the generalized three-cornered hat method, we determined the accuracy and uncertainty of three precipitation products (GPM, ERA5, and CHIRPS) in the upper reaches of the Ili River. The results show that (1) ERA5 showed the highest correlation between POD and FAR, and its moderate and heavy rain precipitation estimates were the most accurate. The root mean square error of GPM was the smallest, and POD and FAR were the lowest. CHIRPS showed the smallest relative bias and mean error, its POD and FAR values were between those of GPM and ERA5, and its light rain precipitation estimates were the most accurate. The accuracy of rainstorm precipitation estimated by the three precipitation products was not high, but ERA5 was better than GPM and CHIRPS. (2) The uncertainty of daily precipitation of ERA5 was between that of GPM and CHIRPS, and the signal-to-noise ratio was the largest. GPM showed the lowest uncertainty of daily precipitation, and the signal-to-noise ratio was between that of ERA5 and CHIRPS. CHIRPS had the largest uncertainty of daily precipitation and the smallest signal-to-noise ratio. (3) The daily precipitation quality of ERA5 was better than that of GPM and CHIRPS, and it can be used to analyze the precipitation characteristics in the upper reaches of the Ili River. GPM had the lowest uncertainty of daily precipitation and is most likely to improve its quality through system calibration. The present findings provide support for hydrological simulation and water resource change analysis in the upper reaches of the Ili River. Figures and Tables | References | Related Articles | Metrics

Land and Water Resources

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Characteristics of soil moisture dynamics and influencing factors of three landscape types at the oasis edge in the middle reaches of the Heihe River HU Guanglu, LIU Peng, LI Jia’nan, TAO Hu, ZHOU Chengqian 2024, 41 (4):  550-565.  doi: 10.13866/j.azr.2024.04.03 Abstract ( 8 )   HTML ( 1 )   PDF (12382KB) ( 3 )   Soil moisture is indispensable for the growth and development of plants in arid zones and determines the dynamics and direction of the succession of arid plant communities. It is particularly important to investigate the dynamic characteristics of soil moisture in different landscape types at the edge of the oasis in the middle reaches of the Heihe River and to develop effective, scientific, and reasonable measures to prevent wind and fix sand to prevent desertification. This study focused on three landscape types—protected forest landscapes, desert-oasis transition zone landscapes, and desert landscapes—at the edge of the oasis in the middle reaches of the Heihe River. HYDRUS-2D model simulation, LSD analysis, and Pearson correlation analysis were used to study the characteristics of soil moisture dynamics and the influencing factors of the three landscape types. The results were as follows: (1) the RMSE of soil volumetric water content ranged from 0.002 to 0.006 cm3·cm-3, MRE ranged from 4.22% to 5.20%, and R2 ranged from 0.725 to 0.967. The simulation results showed a high degree of agreement with the measured data, and the HYDRUS-2D model can be used for simulation studies of soil moisture in this study area. (2) The soil volumetric water content of protected forest landscapes and desert-oasis transition zone landscapes showed a trend of initial increase and subsequent decrease with increasing soil depth, whereas desert landscapes showed a trend of initial decrease and subsequent increase with increasing soil depth. (3) Effective precipitation plays a decisive role in the dynamics of the soil volumetric water content, and precipitation above 9.5 mm significantly increases the soil moisture content and infiltration depth over a short period. The depth of soil moisture infiltration in all periods after precipitation in desert landscapes was higher than that in protected forest landscapes and desert-oasis transition zone landscapes. (4) The soil volumetric water content of the three landscape types was related to factors such as precipitation, evapotranspiration, bulkiness, soil granular composition, and soil water-holding properties. The soil water-holding properties were significantly correlated with factors such as precipitation and evapotranspiration (P<0.01). Of these, precipitation and clay-powder grain content were significantly positively correlated with soil volumetric water content, whereas bulk weight and sand grain content were significantly negatively correlated with soil volumetric water content. Thus, planting windbreak shrubs in the study area can increase the content of soil sticky powder particles, improve the ability of the soil to collect and utilize rainwater, and slow the process of infiltration, thus positively affecting the soil water-holding properties. Figures and Tables | References | Related Articles | Metrics

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Remote sensing retrieval of soil moisture and estimation of vegetation water requirements in the north and south mountains of Lanzhou City ZHANG Hua, YA Haiting, XU Cungang 2024, 41 (4):  566-580.  doi: 10.13866/j.azr.2024.04.04 Abstract ( 9 )   HTML ( 0 )   PDF (17426KB) ( 1 )   To understand the dynamic change characteristics of soil moisture in the arid region of Northwest China, the relationship between vegetation water requirement and soil moisture was explored. The perpendicular drought index (PDI) was determined on the basis of Sentinel-2 L2A and Landsat 8 OLI remote sensing data in combination with 111 soil surface measurements in the 0-10 cm layer. The PDI, modified PDI (MPDI), and vegetation-adjusted PDI (VAPDI) were used to construct a soil moisture inversion model, and four quantitative indicators—determination coefficient (R2), mean absolute error (MAE), mean relative error (MRE), and root mean square error (RMSE)—were used to assess the accuracy of the inversion model. The optimal soil moisture inversion model was selected and used in combination with the soil moisture limiting coefficient. Spatial data of the vegetation area of forest land, grassland, and cultivated land in the study area in 2019 and reference crop evapotranspiration data during the growing season at each station were collected, and a model of the ecological water requirement of vegetation was constructed to explore the spatiotemporal changes in soil moisture and vegetation water requirement in the study area. The results showed that (1) PDI, MPDI, and VAPDI determined using the two data sources showed a linear negative correlation with the measured data to varying degrees, and the coefficient of determination R2 was 0.37, 0.64, and 0.59, respectively. The model evaluation indicators suggested that the soil moisture regression model of MPDI had the highest fitting coefficient of determination. The spatial distribution patterns of soil moisture obtained from the two remote sensing data were consistent. (2) The high-resolution Sentinel-2 L2A soil moisture inversion was more precise, and the overall soil moisture showed a fluctuating growth trend. The multitime average of soil moisture was 23.27%; it showed a trend of initial decrease, followed by an increase and subsequent decrease, with an overall growth rate of 74.07%. (3) The average vegetation water requirement and soil moisture content of the northern and southern mountains of Lanzhou City from April to October showed a trend of fluctuation and decline. The maximum vegetation water requirement between April and October was 3.98×107 m3—observed in July—and the minimum water requirement was 0.97×107 m3—observed in October. With the implementation of the environmental greening project, the northern and southern mountains of Lanzhou City have gradually formed a community structure of multispecies combination from only drought-tolerant herbs and low shrubs. In general, this study provides a reference for the rational use of soil water resources and restoration of vegetation in the two mountains of Lanzhou. Figures and Tables | References | Related Articles | Metrics

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Land use type interpretation and dynamic changes due to water storage projects using support vector machine WANG Jun, CHAI Zhifu, MA Haoyan, ZHAO Zhimeng, WU Jiabin, FU Weiping 2024, 41 (4):  581-589.  doi: 10.13866/j.azr.2024.04.05 Abstract ( 8 )   HTML ( 1 )   PDF (10147KB) ( 2 )   In this study, to further restore and reconstruct the historical process of land use change before and after the construction of a water storage project and better grasp and forecast the direction of land use transfer, adaptive research on land use type interpretation was performed using the support vector machine theory. The adaptive adjustment ability and evolution direction of the land use structure before and after the construction of a water storage project were analyzed by examining the dynamic change in land use. The main conclusions were as follows: (1) The overall classification accuracy of the support vector machine for land use type interpretation is as high as 91.7%, and the Kappa coefficient is 0.90, depending on the advantages of self-learning and self-adaptation. In contrast with the relatively low accuracy observed for cultivated land producers, higher classification and recognition ability was observed other land types such as water bodies and forest land. (2) The Google Earth Engine (GEE) platform was used to examine the evolution process of land use types; it was found that the implementation of the second stage of the “Three-North Shelterbelt” project (2001-2020) significantly increased the area of construction land and forest land and increased the area of forest land by nearly five times compared with the initial stage of implementation in 2000. (3) Since the construction and operation of the project, nearly two-thirds of the area of forest land and construction land have maintained their original appearance, water bodies and unused land have been affected by water conservancy and urban construction projects, and more than 65% of the area has transformed from the original appearance type to other types. The “Three-North Shelterbelt” project accelerated the increase in forest area and improvement in grassland vegetation cover, and the net increase in the transformation of low-cover grassland to medium and high-cover grassland was 48.0% and 50.2%, respectively. Figures and Tables | References | Related Articles | Metrics

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Analysis of spatiotemporal evolution of land use and its driving mechanism in the agro-pastoral ecotone of Gansu Province using Geodetector LI Wenxiu, YAN Zhengang 2024, 41 (4):  590-602.  doi: 10.13866/j.azr.2024.04.06 Abstract ( 8 )   HTML ( 0 )   PDF (14552KB) ( 2 )   This study analyzed the land use structure, dynamics, intensity, and land use conversion of the agro-pastoral ecotone of Gansu Province from 2000 to 2020 using remote sensing (RS), geographic information system (GIS), and Geodetector in combination with social and economic data. (1) From 2000 to 2020, cultivated land, forest land, and grassland were the main land use types in the agro-pastoral ecotone of Gansu Province, and the total proportion of the three was more than 95%. The difference degree of land use structure was less than 0.01, and the structure was generally stable. The overall land use change initially increased and subsequently slowed down over time. (2) The conversion of cultivated land, forest land, and grassland accounted for more than 96% of the total conversion area in the agro-pastoral ecotone of Gansu Province. Land use conversion was observed among all land use types. Converted cultivated lands were mainly converted to forest land and grassland, whereas other land use types were converted to construction land. Land use type changes were mainly concentrated in the Loess hills in central Gansu and the Loess Plateau gully region in eastern Gansu. (3) In the context of long term land use changes, Geodetector demonstrated good applicability. The driving factors for land use changes in the farming-pastoral ecotone of Gansu varied during different periods. These changes were driven by a combination of socioeconomic factors and natural geographic factors, with the former having stronger explanatory power for land use change. Interactions among these factors exhibited either two-factor enhancement or nonlinear enhancement. Two-factor interactions had stronger explanatory power for land use changes than single-factor explanations. Figures and Tables | References | Related Articles | Metrics

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Soil wind erosion and nutrient loss in typical rodent mounds in a degraded alpine grassland in the Yellow River source zone YUE Dalin, LI Guorong, LI Jinfang, LI Xilai, ZHAO Jianyun, ZHU Haili, LIU Yabin, HU Xiasong 2024, 41 (4):  603-617.  doi: 10.13866/j.azr.2024.04.07 Abstract ( 9 )   HTML ( 2 )   PDF (16281KB) ( 1 )   Numerous rodent mounds are found in areas with rodent activity in alpine grasslands in the Yellow River source zone, and soil wind erosion easily occurs owing to the dry and windy climate. The present study investigated the characteristics and trends of soil wind erosion in rodent mounds using plateau pika (Ochotona curzoniae) and plateau zokor (Eospalax baileyi) mounds in 14 test areas at different altitudes and with different vegetation coverage in the Yellow River source basin. Field-simulated wind erosion was used to determine the trends of soil loss and nutrient loss in rodent mounds in different regions under different wind speeds. The results showed a significant difference in the amount of soil loss from wind erosion between the different regions (P<0.05). When the wind speed was low, there was no significant difference in soil loss between the two types of rodent mounds. When the wind speed was increased to 12 m·s-1, the soil loss in the plateau pika mound was greater than that in the plateau zokor mound (P<0.05). When the wind speed increased from 3 to 12 m·s-1, the average increase in soil loss in the two types of mounds was 238.16% and 146.31%, respectively. (2) The wind erosion rate of the mound soil in each test area generally showed a decreasing trend with decreasing wind speed. Vegetation coverage was a significant factor affecting the mound soil loss at low wind speeds and was related to altitude. (3) With an increase in grassland degradation levels, the soil total nitrogen content, available nitrogen, available potassium, and organic matter content decreased significantly, whereas total phosphorus, total potassium, and available phosphorus showed an upward trend. This study shows that the difference in soil wind erosion in different regions of the Yellow River source zone is closely associated with soil moisture content, particle size, and wind speed. Figures and Tables | References | Related Articles | Metrics

Plant Ecology

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Species diversity in Minqin clay sand barrier-artificial Haloxylon ammodendron plantations and the characteristics of soil moisture changes SONG Dacheng, MA Quanlin, LIU Shiquan, WEI Linyuan, WU Hao, DUAN Xiaofeng, GUO Shujiang 2024, 41 (4):  618-628.  doi: 10.13866/j.azr.2024.04.08 Abstract ( 8 )   HTML ( 2 )   PDF (3778KB) ( 2 )   In the present study, clay sand barrier-artificial Haloxylon ammodendron plantations and a mobile sand site (control) in the Minqin desert area were used to investigate the plant species composition, species importance value, dominant species characteristics, species diversity, and soil moisture content. This study explored the long term effects of clay sand barrier-artificial Haloxylon ammodendron plantation construction on regional plant community structure, species diversity, and soil moisture. In total, 12 species belonging to 12 genera and 6 families were recorded in the clay sand barrier-artificial Haloxylon ammodendron plantations in the Minqin desert area, with Chenopodiaceae and Zygophyllaceae being the dominant families. The construction of the artificial sand control system significantly increased the number of plant species in the region (from 4 species to 5-8 species). With an increase in the installation period, the vegetation structure gradually evolved from Agriophyllum squarrosum and Haloxylon ammodendrine (dominant species) to Grubovia dasyphylla, Kali collinum, Limonium aureum, and Haloxylon ammodendrine (dominant species). The life forms also shifted from a single type dominated by annual herbaceous plants to a composite type consisting of annual herbaceous plants, perennial herbaceous plants, and shrubs. Regarding alpha diversity, species richness index, Shannon-Wiener index, Simpson index, Pielou index, and Alatalo index showed an overall unimodal trend, with the highest species number and most even species distribution observed in the 20-year installation site and the lowest species number and most uneven species distribution observed in the control sand site. The Jaccard index of plant community similarity between neighboring sites with various installation periods showed the following order: control sand site > 1-year installation site > 20-year and 40-year installation sites > 1-year and 5-year installation sites > 10-year and 20-year installation sites > 40-year and 60-year installation sites > 5-year and 10-year installation sites. The dissimilarity index and Cody index showed the opposite trend. The fluctuation pattern of the regional soil moisture content was consistent with the trend of plant community succession. Compared with deeper soil layers (40-60 cm), the role of shallow soil layers (10-30 cm) in the natural succession process of regional plants was more pronounced. Figures and Tables | References | Related Articles | Metrics

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Spatiotemporal variation in vegetation coverage in Inner Mongolia and its response to human activities PEI Zhilin, CAO Xiaojuan, WANG Dong, LI Di, WANG Xin, BAI Aiyuan 2024, 41 (4):  629-638.  doi: 10.13866/j.azr.2024.04.09 Abstract ( 8 )   HTML ( 3 )   PDF (13973KB) ( 4 )   In the context of global climate change, the spatiotemporal characteristics of fractional vegetation coverage (FVC) serve as a crucial indicator for assessing ecological environment quality in various regions. However, the specific spatiotemporal variations, change trends, and underlying mechanisms of FVC response to human activities in Inner Mongolia remain undefined. Bridging this knowledge gap is essential for understanding ecological management outcomes and providing a scientific basis for local ecological policies and spatial planning. Using MOD13A1 NDVI data, land cover data, and nighttime light data spanning from 2000 to 2022, we calculated the annual maximum fractional vegetation coverage in Inner Mongolia and explored its spatiotemporal variations. Additionally, we illustrated the change trends in FVC. We conducted pixel-by-pixel correlation analysis to examine the response modes of FVC to human activities. Our findings reveal the following: (1) FVC distribution in Inner Mongolia demonstrated a decreasing trend from northeast to southwest, consistent with the overall precipitation changes in China. Notably, areas along the Yellow River, such as the Houtao Plain and the Qiantao Plain, exhibit relatively higher FVC due to abundant water resources and well-developed agriculture. Overall, FVC showed improvement with a growth rate of 0.0039·a-1, remaining relatively stable in most areas (64.02%) and significantly increasing in 31.64% of the region, all prefecture-level cities showing a positive average annual growth. (2) Changing trends in FVC were predominantly nonsignificant (65.62%), followed by a significant increase (17.36%), an extremely significant increase (13.43%), a significant decrease (3.27%), and an extremely significant decrease (0.32%). Regions experiencing significant and highly significant reductions displayed a strong spatial correlation with newly developed construction land. (3) Regarding human activities in Inner Mongolia, most regions (79.67%) showed no significant influence on FVC changes. In 12.80% of the regions, human activities positively impacted FVC, primarily in grassland and arable land areas surrounding urban zones. Conversely, 7.53% of the regions demonstrated a negative impact of human activities on FVC, chiefly in areas undergoing land cover transitions from arable land to construction land and newly added industrial and mining zones. While most regions showed no significant correlation between FVC variation and human activities, this does undermine the impact of ecological protection policies implemented in China like the “Ecological Protection Red Line” and “Arable Land Red Line.” The effectiveness of these measures lies in preventing land type conversion, such as grassland and arable land to other categories. This not only maintains the stability of FVC within protected areas but also regulates the intensity of human activities. However, the outcomes of these measures are not adequately reflected in nighttime light data. Therefore, while nighttime light data partially reflect the influence of human activity intensity on FVC, its limitations must be fully recognized in the comprehensive evaluation of ecological protection policies. Figures and Tables | References | Related Articles | Metrics

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Dynamic change characteristics and driving forces of vegetation cover in the Ulan Buhe Desert along the Yellow River ZHAO Dongying, MENG Zhongju, MENG Ruibing, MA Ze 2024, 41 (4):  639-649.  doi: 10.13866/j.azr.2024.04.10 Abstract ( 9 )   HTML ( 0 )   PDF (10931KB) ( 2 )   Based on Landsat imagery data from 2001 to 2021, the NDVI and image dichotomous model were used to estimate vegetation cover and explore the spatial and temporal trends and driving forces of vegetation cover in the Ulan Buhe Desert along the Yellow River. This study aimed to provide a theoretical basis for the restoration of vegetation in the Ulan Buhe Desert along the Yellow River and the selection of key areas for future ecological construction. The results showed that (1) the overall vegetation cover in the study area showed a fluctuating upward trend, and the vegetation restoration status was good. The average vegetation cover increased from 0.294 to 0.526, and this increase was most evident from 2007 to 2017. (2) From 2001 to 2021, the transformation of areas regarding levels of vegetation cover in the Ulan Buhe Desert along the Yellow River was more frequent where large areas of 102.00 km2 and 128.82 km2, respectively, transformed from low and lower vegetation cover to medium and higher vegetation cover, respectively. In addition, the vegetation cover in 42.1% of the study area tended to increase significantly, mainly in the near Dengkou section, whereas that in 4.90% of the area tended to decrease significantly, mostly near the Wuhai section, which should be the key area of concern in future ecological restoration efforts. (3) The spatial variability of vegetation cover in this area is mainly driven by human activities and climate factors. The interaction between the driving factors is mainly enhanced by two factors, among which the key interaction factors with the highest degree of influence are land use type and annual average temperature. In this study, the dynamic change characteristics and driving forces of vegetation cover in the Ulan Buhe Desert along the Yellow River were studied in a systematic and stepwise manner, providing theoretical and empirical support for desertification control, rational land use and high-quality development in the study area. Figures and Tables | References | Related Articles | Metrics

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Temporal and spatial characteristics of ecosystem water use efficiency and influencing factors in Yanchi County, Ningxia, China MA Longlong, YI Zhiyuan, WEI Caiyong, ZHOU Feng, LI Mingtao, QIAO Chenglong, DU Lingtong 2024, 41 (4):  650-660.  doi: 10.13866/j.azr.2024.04.11 Abstract ( 9 )   HTML ( 1 )   PDF (11161KB) ( 2 )   Water use efficiency (WUE) is an important measure of the tradeoff between photosynthetic carbon sequestration and water consumption in ecosystems. Estimation of vegetation’ WUE and analysis of the spatiotemporal distribution of vegetation WUE are crucial for ecosystem preservation as well as the wise use and development of water resources in this area. In this study, we assessed the spatial and temporal characteristics of vegetation WUE and its main influencing factors in Salt Lake County from 2000 to 2019 on the basis of GPP and ET data from MODIS. The results were as follows: (1) Both ET and GPP increased significantly from 2000 to 2019 (P<0.01), and the rates of increase were 7.61 mm·a-1 and 7.23 g C·m-2·a-1, respectively. ET and GPP showed obvious heterogeneity in space. (2) Between 2000 and 2019, the vegetation WUE in Yanchi County fluctuated between 0.80 and 1.11 g C·kg-1·H2O, and the multiyear average value was 0.91 g C·kg-1·H2O. The rate of increase was 0.0013 g C·kg-1·H2O·a-1, but it was not significant. The vegetation WUE showed high heterogeneity in space, with high values mainly distributed in the northeast and low values in the southwest. (3) From 2000 to 2019, WUE mainly increased and decreased in 54.70% and in 45.30% of the area, respectively, in Yanchi County. In the future, 61.48% of the area in Yanchi County will show the same change trends in WUE as in the past, and 38.52% of the area will show reversed trends in WUE. (4) The WUE of each land use type in different study periods decreased in the following order: forest land > cultivated land > grassland. (5) There was a significant correlation between WUE and GPP in Yanchi County (P<0.05), whereas variations in GPP were mainly driven by changes in ET, NDVI, and precipitation, indicating that GPP is the main reason for the changes in WUE in Yanchi County. The Yanchi County Ecological Restoration Project not only enhances vegetation productivity but also increases regional water consumption, resulting in fluctuations in the WUE of the regional ecosystem. This suggests that vegetation restoration in Yanchi County has intensified regional water depletion while enhancing vegetation productivity, which provides a theoretical basis for future ecological revegetation and codevelopment of water resources in Yanchi County. Figures and Tables | References | Related Articles | Metrics

Ecology and Environment

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Migration velocity of barchan dunes at the southern margin of the Taklamakan Desert LIU Xin, GAO Xin 2024, 41 (4):  661-673.  doi: 10.13866/j.azr.2024.04.12 Abstract ( 8 )   HTML ( 0 )   PDF (22486KB) ( 2 )   The movement characteristics of barchan dunes in the southern edge of the Taklamakan Desert reveal wind-sand transport features and geomorphological evolution processes, which are of great significance for the systematic prevention of sand and dust disasters in the region. This study used satellite remote sensing images and meteorological reanalysis data to analyze the morphological changes and moving features of six barchan dune groups along the southern edge of the Taklamakan Desert from 2012 to 2022. The results showed that (1) the average moving speed of barchan dunes within the study area was 6.86 m·a-1, and the moving direction was consistent with the prevailing wind direction in the corresponding region; (2) the association between the morphological parameters of barchan dunes within the area was complex; (3) the movement of barchan dunes is jointly influenced by the wind energy environment, topography, climatic conditions, and vegetation coverage, of which the dune height, underlying surface vegetation coverage, average annual rainfall, and surface temperature were negatively correlated with dune moving speed, and these negative correlations were significantly optimized after regional classification; (4) the average sand transport rate in the study area was 77120.5 kg·m-1·a-1, and it was influenced by the underlying surface conditions and the wind energy environment within the region, which provides an important reference for optimizing sand prevention and control measures. The study results reflect the complexity of the moving pattern of the barchan dunes, and the degree of impact varied with the presence of different geographical environmental factors, which necessitates field-specific analysis. Moreover, the dynamic changes in morphological parameters during the evolution of dunes reveal the internal mechanism of dune migration, providing substantial data for studying the evolution characteristics of dunes and a scientific basis for wind prevention and solidifying work and land planning. Figures and Tables | References | Related Articles | Metrics

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Assessment of habitat quality in the Yellow River Basin in Inner Mongolia from 1990 to 2020 LIU Rulong, ZHAO Yuanyuan, CHEN Guoqing, CHI Wenfeng, LIU Zhengjia 2024, 41 (4):  674-683.  doi: 10.13866/j.azr.2024.04.13 Abstract ( 6 )   HTML ( 1 )   PDF (15861KB) ( 1 )   The Yellow River Basin in Inner Mongolia is an important ecological region in China. Exploring changes in habitat quality and their driving factors is important for regional desertification prevention and biodiversity conservation. Using land use/cover data from 1990 to 2020, GIS technology, and the InVEST model, the habitat quality of the region was assessed, and the driving factors of the spatial heterogeneity of habitat quality were analyzed using geographic detectors. The results indicated the following: (1) The overall spatial distribution pattern of habitat quality in the study area was low in the north and high in the south, with a positive spatial correlation and significant spatial clustering. Areas with low habitat quality, accounting for 23.50%, were mainly distributed in the Kubuqi Desert and the southeastern part of the study area. (2) From 1990 to 2020, the habitat quality in the Yellow River Basin in Inner Mongolia showed a trend of initial decrease and then a slight increase. Over the past 30 years, the area with degraded habitat quality, accounting for 11.97%, was mainly concentrated in the northern part of the study area and near the banks of the Yellow River. It is an area of cultivated land expansion and sandy land distribution, with significant human activity interference. Future research on ecological governance and restoration should focus on this area. (3) Natural factors such as DEM, NDVI, and soil type are the main driving factors for spatial differentiation of habitat quality. The interaction of any two determining factors has greater explanatory power for the spatial differentiation of habitat quality than the corresponding single factors. The study results provide reference and guidance for ecological environment protection and restoration research in the Yellow River Basin in Inner Mongolia. Figures and Tables | References | Related Articles | Metrics

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Landscape ecological risk assessment and prediction for the Yarkant River Basin, Xinjiang, China SI Qi, FAN Haoran, DONG Wenming, LIU Xinping 2024, 41 (4):  684-696.  doi: 10.13866/j.azr.2024.04.14 Abstract ( 9 )   HTML ( 1 )   PDF (9032KB) ( 2 )   Landscape ecological risk evaluation is an essential tool for measuring the safety of ecosystems within a certain range. Taking the Yarkant River Basin as the study area, we synthesized the Markov-PLUS model and the landscape ecological risk assessment index to analyze and predict the evolution characteristics of land use and landscape ecological risk and the change trends under multiple future scenarios and to delineate the risk focus management regions. The results were as follows: (1) Cultivated land, water, and impervious surface in the Yarkant River Basin increased, and woodland, grassland, and unused land decreased from 2005 to 2020. In 2035, land use under Scenario I followed the historical development pattern of change. In comparison with Scenario I, cultivated land increased and other land types decreased in Scenario II; woodland, grassland, and water increased and cultivated land, impervious surface, and unused land decreased in Scenario III. (2) From 2005 to 2035, the landscape ecological risk of the Yarkant River Basin as a whole showed an upward trend, and the spatial distribution was characterized by “low in the southwest and high in the northeast.” The risk deterioration area was mainly concentrated in the alluvial plains at lower altitudes, and the risk maintenance area was mainly distributed in the mountains and glaciers at higher altitudes. (3) In comparison with Scenarios I and II, Scenario III had a smaller average value of the landscape ecological risk index, and it was the optimal future scenario to achieve a win-win situation for both ecological protection and economic development in the Yarkant River Basin. (4) The alluvial plain in the northeastern part of the Yarkant River Basin was a stable high-risk region, the edges of the alluvial plain and the mountains in the west were risk-prone regions, and the mountains and glaciers in the south were increasing-risk lagging regions. The results of this study can provide a reference for the optimization of local landscape ecological security patterns and ecological risk prevention or reduction. Figures and Tables | References | Related Articles | Metrics

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Erosion characteristics of shallow landslides under various land-use conditions: An example of the Caijiachuan landslide WANG Xinying, MA Chao, LYU Liqun, ZHANG Yan 2024, 41 (4):  697-705.  doi: 10.13866/j.azr.2024.04.15 Abstract ( 8 )   HTML ( 0 )   PDF (17332KB) ( 2 )   In recent years, drastic and extreme forms of soil erosion, such as landslides, mudflows, and silt dam outbursts, triggered by extreme rainstorms on the Loess Plateau have attracted widespread attention. From October 3 to 6, 2021, a large shallow landslide disaster was triggered by heavy rainfall along the Caijiachuan watershed in Jixian County, Shanxi Province. In this study, the rainfall process, landslide initiation conditions, and erosion characteristics were analyzed using predisaster and postdisaster unmanned aerial vehicle imagery, historical remote sensing images, and rainfall data provided by the National Field Scientific Observatory for Forest Ecosystems in Jixian County, Shanxi Province. The results show that it was a typical “long-duration, low-intensity” rainfall, with a total precipitation of 121.8 mm in the first 72 h of the initiation of the massive, shallow landslides and a rainfall intensity of 33.2 mm·(6h)-1 during the initiation of the landslides. The landslide triggered by this rainstorm required a slightly smaller catchment area and exhibited higher landslide mobility than the landslide triggered by a typical short-duration, high-intensity rainstorm in 2003; however, the slope of the landslide was not significantly different. Thus, the cumulative rainfall in the early stage was the main factor influencing the occurrence and flexibility of the massive landslide disaster. The magnitude of landslide number probability, area probability, and erosion intensity in catchments with different land use types decreased in the following order: farmland catchment>plantation forest catchment>closed catchment. This finding indicated that the land use type and vegetation cover affect the degree of landslide erosion to a certain extent and that an arboreal-dominated watershed is more unfavorable to landslide initiation. Figures and Tables | References | Related Articles | Metrics

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Sustainable development scale of a typical agro-pastoral ecotone based on emergy analysis: A case study of Ulanqab City, Inner Mongolia WANG Xin, HAI Shan 2024, 41 (4):  706-715.  doi: 10.13866/j.azr.2024.04.16 Abstract ( 7 )   HTML ( 2 )   PDF (4009KB) ( 1 )   The emergy method was used to analyze the sustainable development status of the ecological and economic system in Ulanqab City in the agro-pastoral ecotone from 2011 to 2020, in order to determine the reasonable scale of regional development and achieve regional sustainable development. The results show that: from 2011 to 2020, the input emergy (F) of Ulanqab City’s ecological-economic system increased steadily; the output emergy (Y) continued to decrease; the environmental load rate (ELR) continued to increase; the emergy was sustainable for 10 years The indicator (ESI) experienced large fluctuations and declined overall. From 2011 to 2016, the emergy sustainable development index of Ulanqab City was higher than 1, indicating that the development of the ecological-economic system was sustainable. From 2017 to 2020, the emergy sustainable development index was lower than 1, indicating an unsustainable state. Therefore, in the short and medium term, it is necessary to increase investment in renewable resources to alleviate the ecological environment degradation and high environmental load caused by the overuse of non-renewable resources. The industry should carry out technological innovation to reduce production costs, improve production efficiency, promote the output of high-emergy value products, and seek new emerging technologies. High-emergy value output sectors replace low-emergy value output sectors; the natural growth rate of regional population needs to be increased in the long term in order to increase regional emergy demand and output. With advantageous transportation location and abundant resources, we will undertake industrial sectors with high emergy output rates and low environmental load rates in surrounding relatively developed areas to enhance regional sustainable development capabilities. Figures and Tables | References | Related Articles | Metrics