三峡工程建设期库区耕地的时空变化及驱动力分析

本文通过三峡工程建设前后15年三峡库区耕地的遥感动态监测和耕地变化分析,揭示出耕地变化的影响因子。2007年三峡库区耕地垦殖指数为0.25,三峡工程建设期,耕地资源减少4％,平均每年递减3 977hm2。耕地占补比例为26：1,占补不平衡,土地承载能力不足;减少耕地中优质耕地占61％,耕地质量总体下降;库区2007年人...     

Change of Ecological Footprint and Analysis of Ecological Sustainability —— Taking Zhangjiakou City as an Example

This paper researches the ecological sustainability of Zhangjiakou City, Hebei Province, China, using the ecological footprint model. According to the study we find that Zhangjiakou City was in the situation of ecological deficit from 1990 to 2000 and the deficit had the enlarging tendency. In 1990 the per capita ecological footprint was 0.964 and the per capita ecological capacity was 0.518, thus it can be calculated that the per capita ecological deficit was –0.446. However in 2000, the per capita ecological footprint increased to 1.068, at the same time the per capita eco- logical capacity decreased to 0.471, then the per capita ecological deficit in 2000 was –0.597. Furthermore, this paper studies the ecological sustainability of the city from the changes of the ecological footprint of per 10,000 yuan GDP and the productivity of ecological system. Finally the authors point out the shortage of the model and the way to improve it.     

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 deterior...     

Spatial distribution,sources and ecological risk assessment of heavy metals in Shenjia River watershed of the Three Gorges Reservoir Area

Surface soil/sediment samples were collected from the Water-Level Fluctuation Zone (WLFZ), cultivated land and forest land at 50 different grid points from Shenjia watershed, the Three Gorges Reservoir area in August 2013. The spatial distribution, sources and ecological risk assessment for Arsenic (As), Cadmium (Cd), Chromium (Cr), Copper (Cu), Nickel (Ni), Lead (Pb) and Zinc (Zn) were analyzed in this study. The results showed all tested metals had similar distribution patterns except Ni and Cr, with areas of high concentrations distributed in the southwest (WLFZ and watershed outlet) of the study area. Ni and Cr, which were highly positively correlated and present in high concentrations, were primarily distributed in the south and middle zones of the study area. Lower concentration areas of all metals were uniformly distributed west of the high-elevation zones and forest land. Factor analysis (FA) and factor analysis-multiple linear regression (FA-MLR) showed that the major sources of Cd were fertilizer and traffic sources, which together accounted for 87% of Cd. As, Zn and Cu levels were primarily supplied by industrial and domestic sources, accounting for 76% of As, 75% of Cu and 67% of Zn. Surface soils/sediments of the study watershed contaminated by Cd represent a high ecological risk, whereas other metals represent low ecological risks. The potential ecological risk index (PERI) analysis indicated that it had a low (wide-range) ecological risk and a moderate (small-range) ecological risk primarily distributed in the outlet of the study watershed. Fertilizers and traffic are the primary sources of Cd pollution, which should be more closely controlled for the purposes of water quality and ecological conservation.     

THE EFFECTS OF THE THREE GORGES PROJECT ON ECOLOGY AND ENVIRONMENT

ＴＨＥＥＦＦＥＣＴＳＯＦＴＨＥＴＨＲＥＥＧＯＲＧＥＳＰＲＯＪＥＣＴＯＮＥＣＯＬＯＧＹＡＮＤＥＮＶＩＲＯＮＭＥＮＴＸｉａＹｉｃｈｅｎｇ（夏宜铮）（ＩｎｓｔｉｔｕｔｅｏｆＨｙｄｒｏｂｉｏｌｏｇｙ，ｔｈｅＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎｃｅｓ，Ｗ...     

基于综合承载力的北京市适度人口研究

北京作为中国的政治、经济和文化中心,资源短缺、交通拥堵和生态环境恶化等问题日益严重,确定其适度人口规模,对引导区域人口合理流动和环境保护具有一定的现实意义。本文基于综合承载力,对已有的适度人口模型进行了改进：利用主成分分析法和熵权法确定生态、经济和资源承载系统的权重;经济承载人口测算指标不局限于地区生产总值（GDP）这一单一指标;资源承载人口综合考虑了土地资源和水资源承载力。本文通过综合分析2004-2014年北京各项承载人口和适度人口,结果表明：① 生态承载人口规模在波动中有增长的趋势,由717.38万人上升至753.14万人,一直处于人口超载状态;② 经济承载人口一直处于富余状态,但规模由5297.18万人减少至3802.06万人。第三产业产值所承载的人口对经济承载人口的贡献最大,在2014年达到65.15%;③ 资源承载人口规模处于波动状态,2014年为139.61万人,超载率逐年增加。土地资源承载力对资源承载人口的贡献大于水资源,2014年贡献率达79.91%;④ 北京市适度人口规模从2004年的2031.15万人减少至2014年的1550.67万人,2008年开始出现人口赤字,且人口超载率逐年攀升。经济承载人口对适度人口贡献率维持在80%以上,生态和资源承载人口的贡献率平均值分别为14%和3%。人口资源压力指数在波动中有上升的趋势,从2004年的9.45上升至2014年的15.41,资源约束已经成为阻碍城市发展的主要因素,经济承载力是维持适度人口规模缓慢减小的主要动力。     

黄河三角洲高效生态经济区生态环境承载力分析

以黄河三角洲19个地区2010年统计年鉴的数据为依据,应用生态足迹法,对该区2010年的生态足迹进行计算与分析。结果表明,黄河三角洲地区的生态足迹均为赤字,人均生态足迹为68．396 hm2,人均实际可利用生态承载力为14．057 hm2,人均生态赤字为54．339 hm2。反映出评价区人类的生产、生活强度超过了生态系统的承载能力,区域生态系统处于被人类过度开发利用状态。     

Effects of seasonal water-level fluctuation on soil pore structure in the Three Gorges Reservoir,China

Inundation of the Three Gorges Reservoir has created a 30-m water-level fluctuation zone with seasonal hydrological alternations of submergence and exposure, which may greatly affect soil properties and bank stability. The aim of this study was to investigate the response of soil pore structure to seasonal water-level fluctuation in the reservoir, and particularly, the hydrological change of wetting and drying cycles. Soil pore structure was visualized with industrial X-ray computed tomography and digital image analysis techniques. The results showed that soil total porosity(? 100 ?m), total pore number, total throat number, and mean throat surface area increased significantly under wetting and drying cycles. Soil porosity, pore number and throat numberwithin each size class increased in the course of wetting and drying cycles. The coordination number, degree of anisotropy and fractal dimension were indicating an increase. In contrast, the mean shape factor, pore-throat ratio, and Euler-Poincaré number decreased due to wetting and drying cycles. These illustrated that the wetting and drying cycles made soil pore structure become more porous, continuous, heterogeneous and complex. It can thus be deduced that the water-level fluctuation would modify soil porosity, pore size distribution, and pore morphology in the Three Gorges Reservoir, which may have profound implications for soil processes, soil functions, and bank stability.     

Effects of contour hedgerow intercropping on nutrient losses from the sloping farmland in the Three Gorges Area, China

Eutrophication is recognized as one of the major environmental problems in the Three Gorges Reservoir.Contour hedgerows have been used as a major soil and water conservation measure in this area.Accordingly,a two-year study was conducted to investigate the effects of contour hedgerow intercropping on nutrient loss from sloping farmland in this area.Four treatments were applied:(1) Maize + Soybean,(2) Maize,(3) Maize + Alfalfa,and(4) Maize + Hemerocallis citrina Baroni.Results indicated that nutrient loss in the control treatment(Maize) was serious,especially the average loss flux of total nitrogen(2245.8 mg) and total phosphate(2434.2 mg) in a typical rainfall event.However,the nutrient losses by runoff in the other three treatments with contour hedgerow intercropping showed significant reduction.Compared with the control treatment,the total nitrogen loss in the Alfalfa and Hemerocallis citrina Baroni decreased by 80.9% and 85.0%,respectively,and the total phosphorus loss in the two treatments decreased by 91.2% and 92.5%,respectively.Therefore,it is concluded that nutrient losses could be reduced by using contour hedgerows in the Three Gorges Region.Reducing runoff volume and sediment loss was the main mechanisms of contour hedgerow intercropping to reduce nutrient loss.     

Influencing factors of sediment deposition and their spatial variability in riparian zone of the Three Gorges Reservoir,China

Many factors can affect the sediment deposition and soil erosion process in riparian zone, including terrain, sediment transport and water level fluctuations. Clarifying the factors influencing sediment deposition process in the riparian zone of the Three Gorges Reservoirs is an important problem to determine the key area of sediment deposition and its trend of development in the study area. In order to reveal the influence of these environmental factors on the sediment deposition in riparian zone of the Three Gorges Reservoir, this study investigated 1) the amount of deposited sediment in different environmental conditions, 2) the potential factors affecting sediment deposition in riparian zone of the Three Gorges Reservoir, 3) the relationship between the deposited sediment amount and these factors previously mentioned using correlation analysis, and 4) the influence of human activities considered as an additional factor. This study found that 1) slope gradient, elevation, inundating duration and human activities were the main factors influencing sedimentation in riparian zone of the Three Gorges Reservoir, and 2) the impact of each factor varied with spaces. Specifically, in the upper reach from Jiangjin to Fuling, human activities such as gravel dredging, bank revetment and ports and wharfs constructing disturbed considerable amounts of deposited sediment, as a result, there was no natural law to dictate the distribution. In the middle reach from Fuling to Fengjie, slope gradient and inundating duration were the controlling factors, and the sediment deposition amount was greater in the areas with a gentler slope or lower elevation. Water flow on gentler slopes generally had lower velocity, resulting in more sediment to deposit. Sites with lower elevations would be drowned by sediment-laden flow with a longer duration resulting from hydrologic regime controlled by the operating strategy of the Three Gorges Reservoir, leading to a larger amount of sediment deposition. In the lower reach from Fengjie to Zigui, slope gradient was similar to the middle reach, performing a primary factor, while other factors showed little relationship with sediment amount.     

Sustainable land use planning based on ecological health

This paper, taking Beiwenquan Town of Beibei, Chongqing as an example, assessed the impacts of land use on ecological health by comprehensive index method, and discussed methodological system of sustainable land use planning based on ecological health. Results indicated that: 1) From 1992 to 2002, land use changes focused on 12 patterns with the total conversion area of 92.11%, which were related to cultivated land, residential and industrial-mining area, and orchard land. Urbanization and economic reconstruction with the leading driving forces. 2) There was obvious difference of the areas of ecotypes driven by land use change in wide valley and mild slope between 1992 and 2002, while there were little or no difference in steep slope and very steep slope. 3) Both of the conditions of ecological health in 1992 and 2002 were sound, and the ecotypes focused on the types of health and sub-health. But, health ecosystem in 1992, with an area of 764.64ha, accounting for 38.51% of the total evaluation area, was better than that in 2002, with an area of 636.10ha, accounting for 34.19% of the total evaluation area. 4) The ecotypes involved into different ranges have already degenerated, due to humankind’s disturbance, while the conditions of ecological health in the same range in 1992, regardless of stability and reconstruction, were better than that in 2002. 5) The planning scenario based on ecological health was accorded with the practice condition of Beiwenquan Town: 388.29ha of cultivated land could meet the Beiwenquan demand of food and byproduct; 1045.26ha of forest land area, the Beiwenquan demand of ecological health; and 1004.73ha of the residential and industrial-mining area, the Beiwenquan building demand. 6) Sustainable land use planning based on ecological health had higher useful value, because it not only stood to ecological theory, but also satisfied the development demand of society and economy. Foundation item: Under the auspices of the Key Project of Science and Technology of the Ministry of Education (No. 03111) and Incubation Fund Project of Science and Technology Committee of Chongqing (No. 017079) Biography: SHAO Jing-an (1976-), male, a native of Bozhou of Anhui Province, Ph.D., specialized in land use and eco-environmental evolution. E-mail: shaojinganswau@yahoo.com.cn     

基于LUCC的张家界市生态补偿研究

本文基于张家界市土地利用/土地覆盖变化,通过改进的生态系统服务价值与生态足迹的方法,测算了研究区域的生态补偿额度。研究表明:(1)从2001~2013年张家界市各县(区)生态系统服务价值变化率来看,永定区呈下降态势;增幅最大的是武陵源区,其次是桑植县,慈利县增幅最小。(2)2013年张家界市的人均生态足迹为1.3625 hm~2,而实际生态承载力为0.9556 hm~2,人均可利用生态承载力为0.8409 hm~2,则人均生态赤字为-0.5215 hm~2。(3)计算出了张家界市各县(区)的生态补偿标准,其中慈利县需要支付的生态补偿量最高,为18.61亿元;其次是永定区,为10.49亿元;再次是武陵源区,为582.12万元;最小的是桑植县,为359.70万元。评价结果将促进张家界市生态环境保护和经济社会的可持续发展。     

Forces driving changes in cultivated land and management countermeasures in the Three Gorges Reservoir Area, China

The Three Gorges project accelerates economic development in the Three Gorges Reservoir Area.This paper aimed to investigate the distribution,changes and features of cultivated land in this area,analyze the forces driving the changes in cultivated land area,and propose the countermeasures for cultivated land management.Transition matrix was used to analyze the features of cultivated land changes,and quantitative analysis and qualitative analysis were adopted to research the driving forces according to the features of cultivated land changes.Cultivated land in the Three Gorges Reservoir Area mainly lay to the northwest of the Yangtze River,especially the upper reaches.The areas of cultivated land increased from 1996 to 1999,then decreased from 2000 to 2006,and finally increased again from 2007 to 2009.The important forces driving changes in cultivated land included government policies,employment and food security,increasing construction land,agriculture structure adjustment,land rearrangement,inundation.During cultivated land management,firstly,it is necessary to insist on the principle of cultivated land protection,standardize land exploitation and strictly restrict the transformation of cultivated land into non-farming land.Secondly,land rearrangement must be implemented,which can not only increase the area of the cultivated land,but also improve the quality of the cultivated land.Thirdly,it is feasible to intensify eco-agriculture construction to increase the quantity and quality of cultivated land.Fourthly,it is helpful to improve the traditional agriculture production methods to promote cultivated land quality.Lastly,it is important to propagandize cultivated land protection and realize the enormous pressure of cultivated land shortage,making more people obligated to protect cultivated land.     

Wave attenuation mechanism of cross-plates applied in landslide-induced tsunami in river course

Since the impounding of the Three Gorges Reservoir, the channel of the Yangtze River has become a busy watercourse and the probability of landslide-induced tsunamis has increased. In the case of landslide-induced tsunamis in the Three Gorges Reservoir, even after shipping closures in advance, there are still facilities and objects in urgent need of protection within the risk zone of the watercourse, such as wharfs, marine fueling stations, berthed ships. The emergency protection against and decay of landslide-induced tsunamis in inland watercourses is a new challenge. In this study, 37 sets of wave decay experiments were conducted with the hydromechanics numerical method. The wave decay efficiencies of common simple structures including submerged horizontal plate, horizontal plate on the water surface, inclined thin plate and cross-plates in coastal areas were compared and analyzed. Cross-plates structure showed better wave decay capacity than other simple plates. The wave decay performance of cross-plates was related to five modes of energy dissipation and transformation, namely run-up/run-down, overtopping, reflecting, return flow and disturbed wave orbital path. The type of wave had little relation with the decay performance of cross-plates, but a strong correlation with cross-plates structure, especially the height of the vertical emerged plate. The best decay performance was observed when the ratio of wave amplitude to emerged vertical plate height was between 1 and 1.5, which can reduce up to about 80% of the incoming wave amplitude. Finally, the emergency way of cross-plates applied to the decay of landslide-induced tsunami in river course is discussed. This study provides a conceptual reference for related studies to practice the attenuation of landslide-induced tsunami in reservoirs.     

长江三峡水库蓄水后的首发微震群活动

长江三峡水库2003年5月19日正式蓄水，6月7～30日发生可定位0级以上地震131次，其中最大为ML2．1。经分析，该微震群活动与水库蓄水有关。     

Tempo-spatial variations of sediment-associated nutrients and contaminants in the Ruxi tributary of the Three Gorges Reservoir,China

Ruxi River is a tributary of the Three Gorges Reservoir. This study examined the temporal and spatial dynamics in particle size characteristics and the associated nutrients and contaminants of the fluvial suspended and deposited sediments along the Ruxi River. Temporal variations in the particle size distribution of the suspended sediment are controlled mainly by differences in sediment source during different seasons. Total organic carbon(TOC), total nitrogen(TN) and total phosphorous(TP) in the 62μm fraction of the suspended sediment exhibit considerably higher concentrations in spring,indicating high probability of algal blooms in the backwater areas. Downstream trends in the nutrient contents of 62 μm deposited sediments imply the greatest potential for eutrophication in the backwater ends, where highest nutrient concentrations were detected. Assessment of metal contamination shows that the sediments deposited in the water-level fluctuation zone were moderately to strongly contaminated by Cadmium(Cd), with a considerably high potential ecological risk. The findings reported have emphasized the impacts of reservoir impoundment on aquatic and/or terrestrial environment in this region. More information on physical, chemical and biological processes of sediment and sediment-associated materials are needed for developing environmentally and ecologically sound policies of water and sediment management.     

Opportunistic-tended life history traits of Siniperca kneri in the Three Gorges Reservoir,China: potential responses to impoundment

Reservoir impoundment changes original fluvial habitats into lentic environments. Fish species adapted to lentic habitats may take the advantage of such habitat changes and show typical life history traits might facilitate the population increase. Siniperca kneri rarely occurred in fishery landing in the Three Gorges Reservoir(TGR) area before its impoundment in 2003, but it is now a dominant species. In this study, a total of 438 females of S. kneri were collected monthly during September 2012 through January2014 using gill nets in the TGR. The age, growth, and reproductive biology were then investigated, and compared with other S. kneri populations. The standard length at age 1 was 149.9 mm in the TGR, which is larger than the three compared populations(i.e., Sandaohe Reservoir, Xinfengjiang Reservoir, and North River), but smaller than one(the Guishi Reservoir). The youngest mature female in the TGR was age 1,which is younger than that of the two compared populations(i.e., Xinfengjiang Reservoir and the North River). The relative fecundity in the TGR was 140 eggs/g, which is higher than that of the only available compared population(Xinfengjiang Reservoir, 96 eggs/g). Our results demonstrated that S. kneri in the TGR tended to have faster growth in the first year, a younger age at first maturation, and higher reproductive ef fort.We suggest that such opportunistic-tended life history traits might facilitate rapid increase of the population.     

Spatial-temporal pattern and differences of land use changes in the Three Gorges Reservoir Area of China during 1975�C2005

Regional land use changes are an important part of global changes. The research on land use changes in the Three Gorges Reservoir Area of China attracts a lot of attention owing to the Three Gorges Dam building. The Three Gorges Reservoir Area becomes one of the important research areas. This study analyzed the transforming processes and traits of each land use type and the regional differences of land use changes during the past 30 years, summarized the distribution of different land use types in different buffer zones and regresses the equation areas and different buffer distances based on buffer analyses and regression analyses, and then analyzed the transforming rules in different buffer distances, got the optimal influence distances. The research results indicate that, (1) cultivated land lies at the northwest of the reservoir and was decreasing, however, the construction land was increasing, especially the urban construction land, a large number of land was flooded because of the reservoir water level rise; (2) urban area was sprawling quickly in developed and neighboring areas, and a great deal of cultivated land and a considerable amount of grassland were occupied; in the earlier time, rural settlements occupied lots of cultivated land and a sum of forestry land in the later time; (3) the optimum influenced distances for cultivated land and forestry land were 10–35 km, and for urban and rural settlements were in 5–20 km. Overall, this research can reflect the spatial-temporal characteristics of land use changes during the 30 years, and it is helpful for urban planning and land use planning in the reservoir area.     

长江三峡库区(奉节-巴东段)移民工程遥感动态监测

在长江三峡库区移民工程中 ,我们采用 ETM+、SPOT、IKONOS等多源、多时相、多分辨率航天、航空遥感数据组合 ,监测移民工程的动态变化 ,通过对库区奉节 -巴东段移民搬迁建与安置、新开发用地分布、土地利用与土地结构变化、地质灾害及衍生地质灾害与防治、库区环境及生态平衡与改善经济结构以及移民工程遥感动态监测等 ,取得突破性进展 ,获取了一批重要成果。为三峡移民工程进一步全面、安全地实施、改进规划管理工作及库区经济可持续发展 ,提供了科学依据和决策性建议。     

Dynamic assessment of rainfall-induced shallow landslide hazard

The assessment of rainfall-induced shallow landslide hazards is a significant issue in the Three Gorges Reservoir area in China due to the rapid development of land in the past two decades. In this study, a probabilistic analysis method that combines TRIGRS and the point-estimate method for evaluating the hazards of shallow landslides have been proposed under the condition of rainfall over a large area. TRIGRS provides the transient infiltration model to analyze the pore water pressure during a rainfall. The point-estimate method is used to analyze the uncertainty of the soil parameters, which is performed in the geographic information system (GIS). In this paper, we use this method to evaluate the hazards of shallow landslides in Badong County, Three Gorges Reservoir, under two different types of rainfall intensity, and the results are compared with the field investigation. The results showed that the distribution of the hazard map is consistent with the observed landslides. To some extent, the distribution of the hazard map reflects the spatial and temporal distribution of the shallow landslide caused by rainfall.