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The objective of this study was to map and discriminate variations of vegetation net primary production (NPP) from the effects of precipitation variability and thereby identify the effects of grazing on NPP variations in the Xilingol Grassland. Satellite-based simulations of NPP collected over 14-year period and residuals method were used to normalize the effects of interannual precipitation on NPP. A fixed-size moving-window method was developed in this paper to quantify the annual grazing pressure (defined as grazing pressure index, GPI) on the regional scale, using vegetation cover images from 2001 to 2014. Temporal and spatial analysis methods were conducted to show patterns and trends of GPI and NPP residuals (NPP res ), and further to examine the effects of grazing pressure changes on variations of NPP res . Our results showed 80.7% of the study area experienced increasing NPP res and 18.5% with significantly increasing trends ( p  < 0.05). 76.7% of the study area showed decreasing grazing pressure, and 11.8% of areas experienced significantly decreasing trends ( p  < 0.05), with a small patches scattered distribution pattern. The negative correlations between NPP res and GPI were found in 94.6% of the study area, and 41.9% with significant correlation ( p  < 0.05); and long-term decreasing grazing pressure had positive impacts on vegetation NPP. They indicate grazing is a main driving factor of variations in vegetation NPP other than precipitation in Xilingol Grassland. The spatial patterns and temporal trends of NPP res , grazing pressure and responses of NPP res to grazing pressure changes varied among three main grassland types. [ABSTRACT FROM AUTHOR]

As one of the most intensively eroded regions worldwide, soil erosion assessment is currently gaining further momentum in the Loess Plateau (LP), China. However, there exist very few review studies that assess soil erosion in relation to land use and land cover (LULC), climate, and ecosystem services (ESs) at multiple temporal and spatial scales in the LP. Thus, this review provides a comprehensive review of the interactions among soil erosion assessment, climate change, LULC change, and ESs at different scales. We focused on the academic literature published in the English language and analyzed the coverage of soil erosion across 109 publications. Our results highlighted three aspects: (1) studies dealing with the effects of LULC change on soil erosion are abundant. A recent surge in research interest is to explore a threshold of vegetation cover to support a sustainable eco-hydrological environment in the LP. However, the impacts of multiple stressors on soil erosion have received limited attention. (2) The short-term soil erosion assessment dominated the published studies. Cross-spatial-scale and long-term erosion assessments have received little attention. (3) 43% of reviewed papers used a field measurement method to assess soil erosion with the validation of measurement methods. 41% of reviewed papers used empirical models to assess soil erosion, but the modeling validation remains an unsolved problem. Then, three recommendations are listed as follows: (1) the combined impacts of LULC and climate change on soil erosion need to be further examined. (2) Long-term and cross-spatial-scale soil erosion assessments need to be established. (3) Soil erosion modeling accuracy on a large scale needs to be developed. • The assessment of multiple stressors on soil erosion has received limited attention. • Poor coverage of multi-spatial scale and long-term soil erosion assessment. • Large scale soil erosion modeling validation remains an unsolved problem. • A recent surge in academic interest is to explore thresholds of vegetation cover in the Loess Plateau. [ABSTRACT FROM AUTHOR]

[Display omitted] • The vegetation cover status of 9 provinces in the Yellow River basin was analyzed. • The water poverty status of 9 provinces in the Yellow River basin is analyzed. • There is a U-shaped relationship between vegetation cover and water poverty. • There were differences in the effects of vegetation cover on WPI components. Vegetation plays an important role in improving the water resource environment. Faced with the serious water poverty problem in various regions of China, whether vegetation restoration can further alleviate water poverty needs to be studied urgently. Taking 9 provinces in the Yellow River basin in China as an example, this paper first uses the framework of the existing water poverty index (WPI) to calculate the WPI of each province over the years from 1999 to 2019 and evaluate the water poverty status of each province. Later, the normalized difference vegetation index (NDVI) was used to analyze the vegetation restoration status of each area. Finally, using provincial panel data for the study area from 1999 to 2019, a comprehensive feasible generalized least squares (FGLS) model was used to analyze the impact of vegetation cover on water poverty. It was found that there was no pure linear relationship between vegetation cover and water poverty; instead, there was a significant U-shaped relationship. Moreover, the influence of vegetation cover on each component of the WPI has certain differences. This research advances knowledge on the relationship between vegetation cover and water poverty and provides ideas for effectively alleviating regional water poverty. [ABSTRACT FROM AUTHOR]

• Spatiotemporal variation in vegetation on the Loess Plateau was investigated. • Precipitation was the greatest driving factor. • There was a bivariate or nonlinear enhancement between all factors. • Key factors' adaptation range or type suitable for vegetation cover was identified. Vegetation, being a core component of ecosystems, is known to be influenced by natural and anthropogenic factors. Studying vegetation cover dynamics variation and its drivers is critical to understanding the interactions between vegetation and ecosystems. The Loess Plateau (LP) is located in a semi-arid and semi-humid region with severe soil erosion and fragile ecology. This paper used the annual maximum Normalized Difference Vegetation Index (NDVI ymax) and growing season mean NDVI (NDVI gsmean) as the vegetation cover indicator. The vegetation cover variation of LP from 2000 to 2020 was analyzed using Sen's slope and Mann-Kendall test. Then the influence of natural and anthropogenic factors on the driving mechanisms of spatial vegetation differentiation was explored by the Geodetector model. The results revealed that the growth trends of NDVI ymax and NDVI gsmean were 0.075/10 years and 0.038/10 years, respectively, and the areas with improved vegetation cover accounted for 92.67 % and 88.58 % of the total area. The vegetation cover of the southeastern and northern parts of the LP decreased significantly; however, the central, southwestern, and northeastern parts exhibited a remarkable improvement. Precipitation, vegetation type, soil type, temperature, and land use type were the key driving forces, ranked differently on NDVI ymax and NDVI gsmean. However, precipitation was the most critical factor both on NDVI ymax and NDVI gsmean. The interaction detection showed non-linear and mutual enhancement, with no independent factor. The findings of our study can assist in identifying the vegetation cover status of the LP, as well as the driving forces, which can provide theoretical support for the formulation of environmental conservation policies. [ABSTRACT FROM AUTHOR]

Differences among regions in the meteorological, surface, and vegetation cover characteristics lead to differences in sediment transport. In this paper, field data were measured above five surface types in the arid zone of northern China to analyze the vertical distribution of sediments in the near-surface transport layer (0-50 cm) and total sediment transport. We were able to express the sediment flux in this zone as an exponential function for all surface types. Sediment transport differed among the surfaces, with the greatest transport above mobile dunes, followed by cultivated land, semi-fixed dunes, fixed dunes, and a shrub community. Vegetation coverage is important for reducing wind erosion and increasing the proportion of the creep sediment transport. With increasing vegetation cover, the soil erosion decreased; the amount for the mobile dunes was 659 times that of the shrub community, and 8 times for fixed dunes. The proportion of sediment transported by creeping differed among the five surface types, with a minimum of 33% for the mobile dunes, and maximum of 44% for the shrub community. [ABSTRACT FROM AUTHOR]

Summary: Soil moisture is an effective water source for plant growth in the semi-arid Loess Plateau of China. Characterizing the response of deep soil moisture to land use and afforestation is important for the sustainability of vegetation restoration in this region. In this paper, the dynamics of soil moisture were quantified to evaluate the effect of land use on soil moisture at a depth of 2m. Specifically, the gravimetric soil moisture content was measured in the soil layer between 0 and 8m for five land use types in the Longtan catchment of the western Loess Plateau. The land use types included traditional farmland, native grassland, and lands converted from traditional farmland (pasture grassland, shrubland and forestland). Results indicate that the deep soil moisture content decreased more than 35% after land use conversion, and a soil moisture deficit appeared in all types of land with introduced vegetation. The introduced vegetation decreased the soil moisture content to levels lower than the reference value representing no human impact in the entire 0–8m soil profile. No significant differences appeared between different land use types and introduced vegetation covers, especially in deeper soil layers, regardless of which plant species were introduced. High planting density was found to be the main reason for the severe deficit of soil moisture. Landscape management activities such as tillage activities, micro-topography reconstruction, and fallowed farmland affected soil moisture in both shallow and deep soil layers. Tillage and micro-topography reconstruction can be used as effective countermeasures to reduce the soil moisture deficit due to their ability to increase soil moisture content. For sustainable vegetation restoration in a vulnerable semi-arid region, the plant density should be optimized with local soil moisture conditions and appropriate landscape management practices. [Copyright &y& Elsevier]

Abstract: For the fragile-ecosystem arid land, the macro and integral information about the land cover types and area is important for the restoration and the improvement of the ecological environment. In this paper, the arid Gaotai County of Gansu Province, China, was taken as a study case to discuss classified method of the arid land based on various indexes. Taking the advantages of different temporal images into account, two TM images acquired in October and June respectively were selected to conduct the research. Firstly, a series of indexes such as NDVI, vegetation coverage, MNDWI, Albedo, Wetness and SI were calculated. Secondly, combining Robert algorithms and artificial experience methods, the integrated index threshold for distinguishing vegetation from other land types was calculated. Thirdly, using the threshold and decision tree classifier, the middle-high and low coverage vegetation were extracted from both two images. Fourthly, the vegetation areas from two images were combined to form the total vegetation cover types (Oasis), which was used to mask October images, and the outside of mask area was continually classified into the types such as the salinization land, water, bare land and wetlands and other land cover types with decision tree classifier. At last, combining all cover types together, the land cover classification map of whole county was produced. Compared with the land cover types interpreted from the high resolution images and field investigation points, this method was found achieving the accuracy of 91.5%. [Copyright &y& Elsevier]

Abstract: In this paper, percentage of vegetation cover in different districts of Wuhan were calculated based on remote sensing images from 1988 to 2002 by employing NDVI method for dimidiate pixel model. Then the vegetation coverage maps in different periods were generated to analyze the temporal change of vegetation coverage of Wuhan. The results showed that, the average vegetation coverage of the whole area was decreased from 58.41% to 50.45%, especially in Jiangxia and urban district. From 1996 to 2002, the vegetation coverage decreased most sharply, while the vegetation coverage increased lightly from 1991 to 1996 in the whole study area. By analyzing spatial changing character in the whole study area we can see that, the whole area was in the decreasing moment, especially in Jiangxia district and the urban district, this was caused by the urban development, and may led to the malign development of the environment, worthy of all aspects of attention. [Copyright &y& Elsevier]

Abstract: Beijing’s mountainous areas have an important ecological significance because they are ecological conservation and water source protection areas of Beijing. The impact of precipitation on the vegetation coverage of Beijing’s mountainous areas is qualitatively analyzed using multi-temporal Landsat images obtained during the last 20 years. Firstly, the influence of external factors, such as phenology and relative radiometric correction, on the normalized difference vegetation index (NDVI) are removed by the normalization of remote sensing images for different periods. Then, the vegetation coverage is calculated using the method of the dimidiate pixel model. Finally, based on that, the relationship between precipitation in different seasons and change of vegetation coverage is discussed. The results indicate that the mean vegetation coverage has the same change trends with winter and summer precipitation, but an opposite change trend with spring precipitation. The paper provides a theoretical basis and data support for further research on driving models of natural vegetation restoration in Beijing’s mountainous areas. [Copyright &y& Elsevier]

Abstract: A thawing ditch existing in permafrost region along the Qinghai–Tibet Railway is studied with their geological features, failure characteristics, ground temperatures, and influence on permafrost roadbed in this paper. The failure shows surface subsidence and horizontal slip on the shoulder. Integrated analysis from the field-monitored data show that the thawing ditch totally subsided more than 11cm from January 2008 to (month) 2010 and the average was close to 6cm a−1. The active layer on both shoulders of the thawing ditch has been slipped inward, and the max horizontal displacement in 0.5m depth was 5–6cm a−1. The warm season is the main period of the failure expanding in scale, especially from August to October. The mean annual ground temperature in shallow layer was about 0.9°C higher in the thawing ditch bottom than in the natural ground (remove about 20m) during the past two years (2008–2009). Due to the vegetation covered on the thawing ditch was destroyed, and the heat absorbed exceeds obviously heat released. The estimated result using the data in 2008 and 2009 shows that the input of heat into the permafrost below the thawing ditch was about 114,000kJ m−2 and was more than the output of 88,000kJ m−2 in twoyears. The heat absorbing starts in mid April, ends at the beginning of November, and lasts over 230days. In addition, the lateral thermal erosion of thawing ditch would influence the surrounding permafrost and damage the adjacent engineering infrastructure. The approximate calculation shows that about 90,000kJ heat was transported from thawing ditch to adjacent permafrost in 2009. Therefore, the permafrost beneath the thawing ditch has been degrading, warming, and declining in stability. [Copyright &y& Elsevier]

Abstract: The eco-environment in the Three Gorges Reservoir Area (TGRA) in China has received much attention due to the construction of the Three Gorges Hydropower Station. Land use/land cover changes (LUCC) are a major cause of ecological environmental changes. In this paper, the spatial landscape dynamics from 1978 to 2005 in this area are monitored and recent changes are analyzed, using the Landsat TM (MSS) images of 1978, 1988, 1995, 2000 and 2005. Vegetation cover fractions for a vegetation cover analysis are retrieved from MODIS/Terra imagery from 2000 to 2006, being the period before and after the rising water level of the reservoir. Several analytical indices have been used to analyze spatial and temporal changes. Results indicate that cropland, woodland, and grassland areas reduced continuously over the past 30 years, while river and built-up area increased by 2.79% and 4.45% from 2000 to 2005, respectively. The built-up area increased at the cost of decreased cropland, woodland and grassland. The vegetation cover fraction increased slightly. We conclude that significant changes in land use/land cover have occurred in the Three Gorges Reservoir Area. The main cause is a continuous economic and urban/rural development, followed by environmental management policies after construction of the Three Gorges Dam. [Copyright &y& Elsevier]

Abstract: In order to reduce the soil erosion rate on the Chinese Loess Plateau, the Chinese government launched in 1999 the “Grain for Green” program (GfG). The objective of this program was to increase the forest cover on steep slopes in the landscape by planting trees and sowing grasses on former cropland. The program was a massive investment by the Chinese government. By the end of 2005 the GfG-program was implemented in an area of 87,000km2 in which about 400–600 million trees were planted. At present it is not known to what extent this program was successful. This paper examines the effects of the GfG-program on the mean annual vegetation cover in the Shaanxi province. A decadal time series of SPOT VEGETATION imagery from 1998 till 2005 were used to calculate NDVI-values in four counties with different rainfall regimes. By means of a regression between preceding rainfall and NDVI-values the effects of rainfall variability were filtered out. A trend analysis of the corrected NDVI time series pointed out that the GfG-program resulted in a significant increase of the vegetation cover on farmland in the northern part of Shaanxi province. In the southern part of the province, which has a more humid climate and large areas of irrigation farmland no significant increase of the vegetation cover on farmland could be detected. [Copyright &y& Elsevier]

Coastal morphodynamics and environmental changes have been obviously altered by global warming, sea-level fluctuations, and human activities. Palynological analysis is one of the most important tools for providing information on vegetation, climate, and environmental change, which can be relatively sensitive indicators of human activity during the Holocene. However, Holocene coastal morphodynamics and palynological evidence from the Pearl River Delta and coastal areas has not been sufficiently studied. In this paper, we carry out analyses using detailed grain-size and palynological records of pollen, spores, freshwater algae, and marine dinoflagellate cysts from Borehole QZK13 in the Pearl River Estuary (PRE), southern China. The results show information relating coastal morphodynamics, vegetation evolution, climate changes, and anthropogenic activities during the Holocene based on radiocarbon chronology. In general, the PRE experienced marine transgressive processes; sea-level and the coastline tended to migrate landward between 10,700 and 4250 cal yr BP. Meanwhile, abundant arboreal pollen (mainly Castanopsis , Quercus -evergreen, Oleaceae, and Castanea) and small amounts of non-arboreal pollen (mainly Poaceae, Cyperaceae, and Artemisia) were observed in Borehole QZK13, which suggests that subtropical evergreen broadleaved forests were distributed throughout the PRE and adjacent areas, and relatively warm and moist climatic conditions were present during the early-middle Holocene. After that, there were relatively cool and wet climatic conditions, and marine regressive processes occurred in the PRE during the Late Holocene (ca. 4250–960 cal yr BP) indicated by an abrupt increase in aquatic herbs and Dicranopteris. Moreover, we hypothesize that the Neolithic "cultural fault" in the PRE is likely related to frequent storm surges induced by extreme typhoon events that occurred ca. 3000–2700 yr BP. • Grain size, pollen, spores, freshwater algae and dinoflagellate cysts from the Pearl River Estuary were investigated. • Three major phases shown by palynological results were corresponding to the changes in vegetation and climate. • We hypothesized that the Neolithic "cultural fault" is probably related to the storm surges induced by extreme typhoon events. • Natural vegetation cover has suffered large-scale destruction by ancient humans during the Late Holocene. [ABSTRACT FROM AUTHOR]

• Ecological land provides wind erosion prevention service (WEPS). • From 1990 to 2015, the area of ecological land decreased while non-ecological land increased. • The effects of five second-level types of ecological land changes on WEPS were discussed. • The transformation of desert to ecological landimproved WEPS. • The improvement of second-level ecological land types with low vegetation cover improved WEPS. As an important "buffer" to slow down the expansion of desertification, ecological land can provide wind erosion prevention service (WEPS), which is closely related to regional ecological security and human well-being. Previous studies have focused on the response of WEPS to land use change, to a certain extent, would easily cause uncertainties, where the same type can be influenced by different physical and anthropogenic factors and further alter the WEPS. To solve this problem, ecological land was defined from the main function of land in this paper as a new indicator, and the impact of ecological land change on WEPS was quantitatively measured. The results indicated the following: (1) During the period 1990–2015, the net area of ecological land reduced by 16,244 km2 or 17.74%. All second-level types of ecological land experienced a decreasing trend. (2) The annual average WEPS rate in the Tarim Basin was 34.82%, which increased by 1.42% across the 25 year period. (3) The increase of WEPS was mainly attributed to the expansion of oasis and the transformation of second-level ecological land types from low vegetation coverage to high vegetation coverage. The transformation of ecological land to desert was the main reason for the deterioration in WEPS. In the period 1990–2015, the protection and effective management of ecological land improved the ecological environment and increased the surface shelter in some regions, which was conducive to the improvement in WEPS. [ABSTRACT FROM AUTHOR]

• The changes of NDVI in urbanized areas of most cities in China exhibited 'U' shapes. • More vegetation degradation was found in urbanized areas than in outer buffers. • Overall, urbanization has negative effects on vegetation for most cities of China. • The adverse effects of urbanization on vegetation gradually diminished over time. • The valid influence distance of urbanization on vegetation may be about 30–40 km. A better understanding the effects of urbanization on vegetation is vital to promoting the sustainable development of cities in China, which has also experienced the world's most remarkable urbanization during the past decades. This paper used satellite-derived night light, vegetation index, and socio-economic data to analyze spatio-temporal patterns of vegetation changes and evaluate the influence of urbanization on vegetation cover in 46 Chinese metropolises over the last four decades. To examine the effects of urbanization on vegetation and its valid distance, we proposed a new method of comparing three indicators, namely, annual average normalized difference vegetation index (NDVI), long-term trend of NDVI change and the proportion of pixels characterized by significant change in NDVI between built-up areas and its multiple buffer zones. The results showed that the effects of urbanization on vegetation have obvious spatial differences. Urbanization generally resulted in the decrease of vegetation coverage in built-up areas for most of China's central and eastern metropolises, while in Western China, usually restricted by natural conditions, the urbanization usually improved vegetation coverage. The rates of increase in NDVI were significant lower than that of the buffer zones for most cities in central and eastern China. Urbanized areas of most cities located in central and eastern China had a higher percent of vegetation pixels, representing degradation than that in the buffer zones. The opposite was true for pixels representing vegetation restoration. The changes of NDVI in the cities in Western China were basically contrary to those in central and eastern China. The impacts of urbanization on vegetation are stage-specific. With the continuous progress of urbanization level, the adverse effect of urbanization on vegetation were gradually diminished or even disappeared. Cities with higher nighttime light levels appeared to have less vegetation coverage in the early years, and negative correlations between mean NDVI and the mean digital number value have become weak in more recent years. The changes in NDVI in urbanized areas of most cities significantly followed a 'U' shape. This phenomenon may further suggest that positive effects of urbanization become more obvious over time during advanced urbanization. The spatial scope of the impacts of urbanization on vegetation was beyond the urban built-up areas, and the effect intensity appeared to attenuate as the buffer distance became further away from the urbanized area. The valid distance of impacts of urbanization on vegetation is generally about 30–40 km. [ABSTRACT FROM AUTHOR]