Effects of ecological projects on vegetation in the Three Gorges Area of Chongqing, China

The construction of the Three Gorges Reservoir and the resettlement project have caused increasing contradictions between human and land,and led to the deterioration of the ecological environment. In order to ameliorate ecological environment of the Three Gorges Area, the government carried out several ecological restoration projects to improve the vegetation coverage from 1990 s. This paper aims to quantitatively analyze the impact of ecological projects on the vegetation in the Three Gorges Area of Chongqing, China. Landsat and MODIS data from 1992 to 2015 were used to estimate vegetation coverage. In addition, the land cover data of the European Space Agency(ESA) was used to explore the impact of ecological projects on land cover change. The cropland accounted for about 62% and the forestland accounted for about 34% of the total area. There was more than 90% of the study area covered with high or very high vegetation coverage.From 1992 to 2015, a total of 272.7 km;croplands were converted into forestland in the Ecological Migration Project(EMP), 795.6 km;in the Grain for Green Project(GGP), and 13.77 km;in the Ecological Restoration Zone Project(ERZP). Among the three projects, the GGP was the most powerful measure,with a contribution rate of 1.6%. The implementation of the ecological projects improved vegetation coverage, which indicated that the ecological projects measures were effective in ecological restoration.

Quantifying impacts of climate and human activities on the grassland in the Three-River Headwater Region after two phases of Ecological Project

The Three-River Headwater Region(TRHR)of China is a typical representative of the alpine environment in the Central Asian plateau and the alpine grassland in the world.Grassland degradation is one of its serious eco-logical problems.The purpose of this study is to quantify the joint impacts of climate and human activities on grassland changes in TRHR after two phases of Ecological Conservation and Construction Project(Ecological Project).Grassland vegetation coverage is selected as an indicator for analyzing grassland changes.We adopt Sen+Mann-Kendall trend analysis,residual trend analysis and correlation analysis methods to analyze the trends in spatial-temporal changes and driving factors of grassland in TRHR from 2000 to 2019.The results show that:(1)The grassland has been mainly restored,and the degraded grassland area only accounts for 1.66%of TRHR.After the implementation of the first phase of the Ecological Project,the percentage of restored grassland area has significantly increased from 8.82%to 24.57%,and slightly decreased during the second phase.(2)The establish-ment of national nature reserves and the implementation of the Ecological Project have changed the situation that“the grassland inside the reserve is worse than that outside the reserve”.(3)Grassland restoration is mainly af-fected by the joint effects of climate and human activities.Nevertheless,grassland degradation is mainly affected by human activities such as overgrazing and grassland reclamation.All of these findings can enrich our under-standing of grassland restoration in TRHR.Artificial measures have certain limitations in promoting grassland restoration.Natural restoration should be considered when human beings strengthen ecological conservation and transform their production and life styles.

Assessment of macrobenthic community function and ecological quality after reclamation in the Changjiang(Yangtze)River Estuary wetland

An ecological optimization project(semi-closed reclamation project)was implemented to control the invasion of Spartina alterniflora,and optimize the habitat of the Chongming Dongtan wetland,in the Changjiang(Yangtze)River Estuary.After project implementation,a macrobenthic ecological survey was conducted in a natural tidal flat and a semi-closed reclamation restoration area within the Chongming Dongtan wetland from 2019 to 2020.Compared with historical data before reclamation,findings showed that the groups,numbers,and species diversity of the macrobenthos increased significantly,and the ecological optimization project resulted in good ecological benefits.In addition,compared to the natural tidal flat,the number of collected macrobenthic phyla,and the macrobenthic density and biomass were significantly lower in the restoration area.Furthermore,the biodiversity index and functional redundancy of natural tidal flats were generally higher,indicating that the community composition and function of natural tidal flats were relatively more stable.Even though the species composition differed between a number of restoration areas and natural tidal flats,there was no difference in functional diversity,indicating that the effect of restoring ecological functions in restoration areas was optimal.Among them,the biodiversity and functional redundancy of Site S2 were significantly reduced,and the ecosystem function was extremely unstable.Habitat heterogeneity,vegetation community and decreasing salinity were the main factors that affected the ecological functions of macrobenthos.The ecological quality was also evaluated;the Transects N3 and N4 showed good quality.The overall ecological quality of the restoration area was generally high,but that of Site S2 was poor and that of Site S2E was merely good,which was mainly due to modifications of the ecological function of macrobenthos.It is suggested that reeds mowing and freshwater species release should be adopted in restoration areas to improve the community function and the environmental disturbance resistance of the macrobenthos.

Lubei Ecological Industry Project:A Case Study in China

Lubei General Company of Enterprise Group, Shangdong Province, set up joint enterprises industrial ecosystem by sharing resources, symbiosis industry and compact structure. As an ecological industry park, the industrial ecosystem has been operated successfully with rich experiment and has become one of ecological industry examples in the world. Based on the case study of Lubei ecological industry project, components of industrial chains, matter recycle and conversion, energy cycle and multilevel utilization, systematic structure and impact factor identification are analyzed and summarized in this paper. The possible extension and development of Lubei ecological industry project in future is brought forward as well.

Community Characteristics of Phytoplankton in Ecological Restoration of Rural Polluted Rivers

The T-type submerged dam based on zeolite and ecological floating bed was set up in Zhujiabang River, a tributary of the Zhihugang River(north of the Taihu Lake), together with ecological restoration measures such as aeration and slope wetland. From the perspective of phytoplankton community, the restorative effect of ecological restoration project on rural contaminated rivers was investigated. The results showed that(i) ecological restoration changed the community structure and succession tendency of phytoplankton, the dominant state of Cyanophyta and Cryptophyta was replaced by some species of Bacillariophyta, Chlorophyta and Pyrrophyta;(ii) ecological engineering restrained the standing stock of phytoplankton community greatly, total biomass of phytoplankton during the restoration period was less than 6 mg/L;(iii) biodiversity of phytoplankton during the ecological restoration maintained at a higher level(mean Shannon-Weiner index was 2.32). Considering the correlation between efficiency of ecological restoration project in purifying water, standing stock of phytoplankton and nutrient level of water, removal of nutrients by ecological restoration project was one of the major factors triggering the change of phytoplankton community characteristics.

Desertification and Blown Sand Disaster in China

Approximately 331 million ha, one-third of China＇s total land, is prone to desertification processes, leading to natural disasters and economic losses. In this study, the situation, tendency, their influences and their risk governance of desertification and blown sand disaster in China were examined using satellite images, field photographs, field data and a literature review. The desiccated areas in Lop Nor and the lower Heihe River fluvial plain covered about 50,000 km2 and 40,000 km2, respectively. In Ejina, about 100 species of vegetation became extinct. The rate of wind erosion in China was between 1,000 tons/km2/year and 2,000 tons/km2/year. There were 12 sand deserts and sandy lands, occupying a total of 710,000 km2. Salinized soils occurred across 99.1 million ha. The two main sand and dust storm-prone areas in China were the Tarim Basin and its surroundings, and the Alxa Plateau and its surroundings. From 1981 to 2007, the annual average frequency of sand and dust storms varied from 1 d to 37 d with a general increase from southeast to northwest. Since 1978, China has implemented a number of ecological construction projects that have reduced desertification from 1999 to 2004 and from 2005 to 2009, and the number of dust and sand storm days from 9.3 d between 1954 and 1959 to 4.4 d between 2000 and 2007. The results could improve understanding of desertification and blown sand disasters in China and provide valuable experiences for global desertification control.

Characterizing changes in ecosystem service values in China's eastern Loess Plateau

Human activities such as the implementation of ecological protection projects and expansion of construction land can cause complex land use changes that affect ecosystem service values （ESV）. In this study, we investigated changes in ESV in response to land use changes in Ningwu County, in eastern Loess Plateau of China. Our aim is to provide guidance for sustainable land use planning in this region. We used remote sensing to evaluate land use changes, and applied a fast, proxy-based method for evaluating ESVat three points in time： 1990, 2000, and 2010. More than 89% of the total ESV in Ningwu County was attributable to woodland and grassland. The ESV in western mountain areas show the greatest increase from 1990 to 2010, but ESV decreased the most in the low-elevation northeastern area of flat terrain These tradeoffs led to a slight net decrease （1.0%） in Ningwu County＇s total ESV. Although the decline in ESV was relatively low compared to the rate of economic growth, total ESV was much lower than global and national average levels at the end of the study period.

Prevention and Control Mode of Desertification in China＇s State Energy Group Shendong Mining Area with Annual Coal Output of 200 Million Tons

According to the strategic goal of sustainable development,construction and management for the construction of Shendong mining area with ecological safety,the ecological restoration principle of ＂ control protects development and development promotes control＂ for desertification prevention and control was adopted,and engineering measures,plant greening measures,and enclosure management and protection measures were taken to prevent and control desertification in the mining area based on careful detailed investigation and accurate planning and design in the early period. After 32 years,the desertification ecological landscape environment of the mining area has undergone a qualitative change,and the vegetation coverage has increased from 3%-8% to above 60% after the development. The former desertification land has become a modern green energy base that has produced 200 million tons of coal every year. The construction and management mode of an ecologically safe and modernized green coal mining area built by Shendong in the desertification region of northwestern China shows that taking appropriate comprehensive ecological restoration construction technology and management measures that integrate engineering,plants and enclosure management and protection is an effective technical and management paradigm for the construction of a modernized green large-scale coal mining area in China＇s arid and semi-arid regions.

2000-2019年中国重大生态工程生态效益遥感评估

We propose a theoretical framework for assessing the ecological benefits provided by key national ecological projects in China over the past 20 years.A dataset consisting of six primary indicators and nine secondary indicators of ecosystem structure,ecosystem quality,and ecosystem services for 2000-2019 was generated using ground survey and remote sensing data.Ecological benefits were quantitatively evaluated following the implementation of these projects in China.Areas with medium,relatively high,and high degrees of ecological restoration accounted for 24.1%,11.9%,and 1.7% of the national land,respectively.Degrees of ecological restoration were higher in areas with greater numbers of ecological projects.Areas with relatively and absolutely high degrees of ecological restoration were mainly concentrated in the Loess Plateau,the farming-pastoral zone of northern China,the Northeast China Plain,and an area spanning the borders of Sichuan,Yunnan,Guizhou,Chongqing,and Hunan.The relative contributions of climatic factors and ecological projects to changes in vegetation net primary productivity were 85.4% and 14.6%,respectively,and the relative contributions of climatic factors and ecological projects to changes in water erosion modulus were 69.5% and 30.5%,respectively.The restoration potential of national vegetation coverage was 20%,and the restoration potential percentage of forest and grassland vegetation coverage was 6.4% and 23%,respectively.Climatic conditions can inhibit ecological restoration.Areas with relatively high and high degrees of ecological restoration were mainly distributed in areas with an average annual temperature greater than 0℃ and annual precipitation greater than 300 mm.Therefore,the limitations associated with climate conditions require consideration during the implementation of national ecological projects.The implementation of combined measures should be emphasized,and the benefits of ecological investment funds should be maximized.

Mechanisms for Realizing the Economic Values of Ecosystem Services

The fact that ecosystem services have values that can be quantified has been widely accepted in recent years. Part of the economic values of ecosystem services have been realized partly by ecological compensation of fiscal transfer payments at different levels, trade and consumption of leisure tourism and ecological products, and carbon sequestration forest funds sponsored by non-governmental capital. However, it remains difficult to realize the economic value of ecosystem services as industrial products and support the coordinated and sustainable development of nature, economy and society. To reveal the role of ecological compensation, consumption of biological products, leisure tourism and ecosystem services trading in realizing the economic values of ecosystem services, we analyzed the composition, transfer and consumption pattern of ecosystem services. In order to provide theoretical and technological support for inter-regional ecological compensation, ecosystem service industry development and ecosystem services trade, the concept of ecosystem services credit and key problems with ecosystem services trading are proposed.

Review of Conversion of Farmland to Forests Project:Ranking First in Investment in the World

The Conversion of Farmland to Forests Project (CFF) is one of the six great forest ecological Projects inChina and one of the ten great forest ecological Projects in the world, ranking the third in overall scale and the first ininvestment. CFF was officially initiated in 2002, covering 1897 counties (county-level cities and districts) in 25provinces (autonomous regions or municipalities) of China. The whole investment is more than 40 billion US$ duringabout 20 years (from 1999 to 2017), aiming to form better ecology system in fragile ecology regions and effectivelycontrol the soil and water erosion of the Yangtze and the Yellow River and sandstorm of the Three-north Regions inChina. The experimental Project of CFF began in 1999, including Sichuan, Shanxi and Gansu province, and the scopeof CFF was widened later. About 1.16 million ha of farmlands were converted to forestlands, and one million ha ofplantation in mountains and wasted lands were completed in 3 years, involving 20 provinces (autonomous regions andmunicipalities), 400 counties, 27 thousand villages, 5.7 thousand towns, 4.1 million farm families and 16 millionfarmers.

Impact of Human Activities and Climate Change on Grassland Productivity in Xilingol League

Natural grasslands are increasingly subjected to the dual stresses of grazing pressures and climate change.However,the contribution of human activities,especially grassland ecology conservation projects,to grassland improvement remains ambiguous.Utilizing MODIS satellite data in conjunction with the VPM model,the gross primary productivity(GPP)changes in the Xilingol grassland from 2000 to 2020 were assessed.Based on GPP data derived from remote sensing,this study quantitatively assessed the spatiotemporal dynamics of the impacts of climate change and human activities on the productivity of grassland in the Xilingol League.From 2000 to 2020,the grasslands exhibited a greening trend characterized by a significant annual GPP increment of 2.66 gC m^(-2) yr^(-1)(P<0.05).Climate change and human activities jointly contributed to this greening trend,with relative contribution rates of 55%and 45%,respectively.However,the relative contributions of climate change and human activities to the trend of GPP varied greatly in different regions.Climate change emerged as the principal driver in the central and eastern regions of Xilingol League with robust grass growth,accounting for more than 65%of the GPP enhancement.Conversely,human activities were the dominant factors in less verdant western regions and the agro-pastoral ecotone,representing more than 60%of the GPP change.Grassland productivity was sensitive to grassland ecological restoration measures,with significant changes in the trends of grassland productivity attributed to human activities in pivotal policy implementation years such as 2005 and 2011.Specifically,measures such as the control of wind/sand sources and returning grazing land to grassland from 2000 to 2005 gradually alleviated the pressure of human activities on grassland productivity,as they significantly improved vegetation growth in high-quality grasslands.Under the forage-livestock balance policy from 2005 to 2011,inadequate compensation for grassland ecological protection led to a significant reduction in GPP,as some herders increased their livestock holdings despite grazing restrictions,and this particularly affected the high-quality grasslands.The implementation of the Grassland Ecological Protection Subsidy and Reward Program from 2011 to 2020 generally promoted the recovery of productivity in eastern and western Xilingol League grasslands,but significant ecological pressure persisted.This study provides theoretical support for optimizing grassland ecosystem management and forming a virtuous cycle of grassland conservation in pastoral areas.