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Much of North China, including the Beijing municipality, is impacted by high levels of water scarcity. As a countermeasure, since the 1990s, Beijing and Hebei Provinces have jointly initiated a series of ecological engineering programs that have the potential to be replicated throughout the region. This study reports on an evaluation of one such program - the Paddy Land-to-Dry Land (PLDL) program - that operated between 2006 and 2015 and involved an incentive payment to farmers to cultivate spring maize instead of paddy rice. The evaluation included a range of water consumption and water degradation indicators based on water footprint and life cycle assessment methodologies. The program was found to be a success in reducing irrigation water demand in each of the three counties where it was implemented: Chicheng, Fengning and Luanping. However, assessment by various indicators, such as the grey water footprint, freshwater eutrophication potential and freshwater ecosystem quality, indicated potential increased risks to water quality, largely related to the higher applications of fertilizer associated with maize cropping. This study demonstrates the importance of using a broad range of indicators when evaluating an ecological engineering project, as well as the potential for such programs to have unintended negative impacts. [ABSTRACT FROM AUTHOR]

To halt the trend of desertification and improve the ecological environment in Beijing, Tianjin and surrounding areas, China establishes the ecological engineering of Beijing-Tianjin Sandstorm Source Control Project. The assessment of ecological restoration after the implementation of ecological engineering is conducive to the ensuing management of ecological engineering. Based on a large number of remote sensing data and calculation models, this study selected land use/cover, vegetation ecological quality indicators such as vegetation coverage and NPP, and other ecological service indicators such as water retention calculated by the InVEST model, soil retention by the RUSLE model, and sand fixing services by RWEQ model to comprehensively assess the degree of restoration and trend of ecological engineering implementation. The contributions of climate change and human activities to NPP and soil retention services are also assessed. We found that from 2000 to 2019, the land cover pattern is optimized, with desert and farmland turning to grassland and forest. The vegetation ecological quality has been improved, sand-fixing service have been significantly improved, and water retention and soil retention service are degraded in some areas. The areas with a high-degree restoration are mainly located in the water source protection areas in the Yanshan mountainous region and in some areas in the south-eastern Horqin Sandy Land, while the areas with a low-degree restoration are mainly located in the desert grassland. The ecological improvement areas are mainly distributed in the mountains in norther Shanxi Province, the water source protection area in the Yanshan mountainous region, the Southern Great Hinggnan Mountains and part of the agro-pastoral transitional grassland. The highly degraded areas are mainly concentrated in the middle of Horqin and Otindag Sandy Lands. Ecological engineering plays an important role in promoting ecological restoration by changing land use types. The contribution proportion of climate change to NPP and soil retention services are significantly higher than those of human activities. The degree of ecological restoration depends on the climax ecological background determined by the climate. [ABSTRACT FROM AUTHOR]

Aiming for the restoration of degraded ecosystems, many ecological engineering projects have been implemented around the world. This study investigates the ecological engineering project effectiveness on vegetation restoration in the Beijing-Tianjin Sand Source Region (BTSSR) from 2000 to 2010 based on the rain use efficiency (RUE) trend in relation to the land cover. More than half of the BTSSR experienced a vegetation productivity increase from 2000 to 2010, with the increasing intensity being sensitive to the indicators chosen. A clear tendency towards smaller increasing areas was shown when using the net primary productivity (NPP, 51.30%) instead of the accumulated normalized difference vegetation index (59.30%). The short-term variation in the precipitation and intra-seasonal precipitation distribution had a great impact on the remote sensing-based vegetation productivity. However, the residual trends method (RESTREND) effectively eliminated this correlation, while incorporating the variance and skewness of the precipitation distribution increased the models′ ability to explain the vegetation productivity variation. The RUE combined with land cover dynamics was valid for the effectiveness assessment of the ecological engineering projects on vegetation restoration. Particularly, the result based on growing season accumulated normalized difference vegetation index (ΣNDVI) residuals was the most effective, showing that 47.39% of the BTSSR experienced vegetation restoration from 2000 to 2010. The effectiveness of the ecological engineering projects differed for each subarea and was proportional to the strength of ecological engineering. The water erosion region dominated by woodland showed the best restoration, followed by the wind-water erosion crisscross regions, while the wind erosion regions dominated by grassland showed the worst effect. Seriously degraded regions still cover more area in the BTSSR than restored regions. Therefore, more future effort should be put in restoring degraded land. [ABSTRACT FROM AUTHOR]

Vegetation restoration in abandoned mines is very difficult and time consuming because of the harshness of the ecosystem, i.e., the extremely high and steep slopes. To accelerate the process of vegetation recovery in abandoned mines, understanding the rules of vegetation succession and the variation in soil characteristics during this process is very important. In the Zhoukoudian vegetation restoration experiment demonstration area (a 12 ha area located in Fangshan District, Beijing, China), engineering measures, such as biological greening bags, eco-stick slope protection, container seedling planting and vegetative-carpet greening technologies, were applied to accelerate the process of vegetation recovery. In this study, 149 human-restored and spontaneously recovering slopes under three substrates were sampled to investigate the dynamic changes in soil and vegetation in different stages of succession by means of space-for-time substitution. WinTWINS was used to classify the samples, which experienced different recovery periods, into 6 plant community types. According to the results, the species richness index, Simpson’s predominance index, the Shannon–Wiener index and the soil fertility of the communities dominated by young trees (V, VI) were higher than those of the communities dominated by grasses (I, II) or shrubs (III, IV); thus, plant communities V and VI are considered optimal representations of severely damaged surface-mine ecosystems. Our results suggest that native species should be planted to accelerate the succession process by implementing the best engineering measures for different substrate types during the initial restoration. [ABSTRACT FROM AUTHOR]

Abstract: Presented in this paper is a low-carbon assessment for wastewater treatment by a constructed wetland as ecological engineering. Systems accounting by combining process and input–output analyses is applied to track both direct and indirect GHG emissions associated with the wastewater treatment. Based on the detailed assessment procedures and the embodied GHG emission intensity database for the Chinese economy in 2007, the GHG emissions embodied in both the construction and operation stages of a pilot constructed wetland in Beijing are investigated in concrete detail, with parallel calculations carried out for a cyclic activated sludge plant as a typical conventional wastewater treatment system for comparison. With the overall embodied GHG emissions taken into account, the constructed wetland is shown to be remarkably less carbon intensive than the conventional wastewater treatment system, and the contrast in GHG emission structure is also revealed and characterized. According to the results, the ecological engineering of the constructed wetland is considered to be favorable for achieving the low-carbon goal. [Copyright &y& Elsevier]

The insufficient information on water conservation dynamics and potential in ecological engineering areas often restrict the selection and implementation of ecological restoration measures in arid and semiarid climates. Based on the regional water balance equation and GIS spatial analysis tools, this article assessed the spatial-temporal changes in water conservation in Xilin Gol League, a representative region of the Beijing–Tianjin Sandstorm Source Control Project Area. The results indicated that the yearly amount of water conservation in Xilin Gol League reached 1.27 billion cubic meters, and annual precipitation of approximately 6.36 mm was retained per hectare. The water conservation capacity in Xilin Gol League showed a notably increasing tendency during the period of 2000–2015 and increased from west to east. The northeast of East Ujimqin Banner had the highest capacity, contributing 16.19% of the total water conservation amount. Compared to 2000, approximately 65.86% of Xilin Gol League presented water conservation capacity increases in 2015, 15.25% of which were significant. The water conservation in Xilin Gol League correlated with the changes in precipitation, temperature, and vegetation coverage, and unfavorable changes in these factors led to a significant decline in regional water conservation capacity. Therefore, multiple ecological restoration strategies are proposed for the improvement of water conservation capacity in the low-efficiency areas. • Dynamic changes in water conservation in ecological engineering area were quantified. • The water conservation capacity notably increased from west to east during 2000–2015. • The water conserved increased in 66% of the study area and decreased in western area. • Rainfall, temperature, and vegetation determine the changes in water conservation. [ABSTRACT FROM AUTHOR]

Evaluating climate and human-induced vegetation change could support managing the sustainability of ecological environment. Based on the Normalized Difference Vegetation Index (NDVI) dataset, meteorological data (temperature, precipitation), land use data and statistical data, this study used a trend quantitative analysis to distinguish the relative roles of climate change and human activities on vegetation degradation and restoration from 1982 to 2015 in Beijing-Tianjin sandstorm source region. Our results demonstrated that the increased vegetation reached 63.8% of the study area during 1982–2015. Using piecewise linear regression method, we identified two turning points within the period 1982–2015 were 1994 and 2004, respectively. By considering the turning points, we found the increasing, decreasing, and increasing trend during 1982–1994, 1995–2004 and 2005–2015, respectively. In 1982–2015, 68.1% of the vegetation change was dominated by the combined effects of climate and human activities, whereas 25.4% was caused by human activities. During 1982–1994, the increasing trend of vegetation was due to favorable climate factors (26.8%) and the combined effects of both (45.4%). In 1995–2004, the vegetation degradation was driven by unreasonable human activities (13%) and the combined effects of unfavorable climate factors and unreasonable human activities (33.1%). However, with the implementation of ecological engineering, the positive human activities (8%) and the combined effects of both (59.1%) were responsible for vegetation restoration during 2005–2015. We noticed that precipitation was the main climate factor limiting regional vegetation change, the sensitivity of vegetation to precipitation was increasing over the study period. Nevertheless, human activities played an increasingly important role in regional vegetation. In particularly, the ecological engineering and increasing precipitation were the main factors for regional vegetation restoration in the past 10 years. Unlabelled Image • The turning points were the year of 1994 and 2004 in vegetation change during 1982–2015. • Vegetation showed an increasing, decreasing, increasing trend during 1982–1994, 1995–2004, 2005–2015. • The combined effects of climate and human activities were responsible for vegetation restoration and degradation. • Ecological engineering significantly improved vegetation restoration. [ABSTRACT FROM AUTHOR]