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This paper presents an empirical analysis of regional disparities from 2000 to 2012 based on a time series of data involving 74 cities within three mega-urban regions along Yangtze River in China. Differing from previous researches on inter-provincial and coastal/interior data, this paper provides a new perspective of mega-urban regions and their cities in China. By Coefficient of Variation and Analysis of Variance the selection of three mega-urban regions along Yangtze River reveals how the mega-urban regional disparities evolve among the east, middle and west up to date in China. In terms of general trend the mega-urban regional inequalities have been decreasing ever since the year around 2005. By traditional regression modeling this paper relates the mega-urban regional inequality and the alleviation to the urbanization and its focus on mega-urban regional development. The regression shows that the evolution of intra mega-urban regions disparities is negatively influenced by the urbanization with meaningful statistical significance from 2000 to 2012. The multilevel regression is further applied based on the nested hierarchical data structure. The results indicate a complicated relationship of the urban population density of the city level, the urbanization ratio of the mega-urban region level and the urban disparities in 2012. Finally limitations and further research advice are provided. [ABSTRACT FROM AUTHOR]

The Gezhouba Reservoir (GR) and Three Gorges Reservoir (TGR) are the two largest water-storage projects in the middle reach of the Yangtze River. The impoundments of the reservoirs have changed natural flow-regimes in the river. This paper uses the Yichang Hydrological Station as a proxy for water-storage projects along the Yangtze River to assess alterations in river-flow conditions in three separate periods. The periods coincide with the start of water storage in the GR and TGR. The ecohydrological conditions in the river system are assessed based on annual discharge, water level, water temperature, and suspended-sediment concentration. More importantly, the entire analysis is done in relation to the Chinese sturgeon species, which face the danger of extinction in the Yangtze River. Based on the research reported in this paper, the impoundment of the GR and TGR increases downstream average annual water-temperature. In contrast, it decreases downstream average annual runoff, water level, and suspended-sediment concentration. The change of hydrological conditions negatively influences the spawning and hatching conditions of Chinese sturgeon. This change is the key reason that causes the fertilized rate of Chinese sturgeon eggs to decline. [ABSTRACT FROM AUTHOR]

Copyright of Regional Studies is the property of Routledge and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the late 1990s, China’s Yangtze and Yellow River Basins suffered devastating natural disasters widely attributed to the degradation of soil and water resources. The Government of China responded with a number of major environmental programs, the most expensive and influential of which, the Grain for Green (GfG) Program, was implemented widely from 1999. Under the GfG Program—also known as the Sloping Land Conversion or Conversion of Cropland to Forest Program—the central government compensates farmers to convert cropland on steep slopes or otherwise ecologically sensitive areas to forest or grassland. Its long-term success depends on households’ ability to make sustainable changes to their household income streams and income diversification strategies. In this paper, we use a difference-in-difference estimation approach to examine the role of migration as a household-level response to the GfG Program, testing the extent to which individuals migrate following a reduction in land available for farming. Importantly, we exploit 15 years of data on migration decisions and establish that participating and non-participating households were on parallel migration paths before the program, thus refuting a key threat to causality in a difference-in-difference model. We find that participating families do, in fact, choose migration as an income diversification strategy more frequently than non-participants. The program effects varied over time but peaked post-Great Recession in 2011 when migration rates in GfG households exceeded those of non-GfG households by 5.9% points (p = 0.003) or about 26%. Our findings should encourage policymakers that families are making long-term adjustments to their livelihood strategies to avoid poverty in anticipation of the eventual withdrawal of government supports. [ABSTRACT FROM AUTHOR]

This study examines the making of local climate governance in the Chinese setting where central-local inter-governmental relations continue to play critical part in almost every policy domain. Through analysing the climate responses of the three provincial-level governments at the Yangtze River Delta (YRD), the paper argues that the process of “experimentation under hierarchy” is relevant to understanding the evolving of the subnational climate regime in the YRD region. We find the preponderance of the central authorities in initiating national climate strategies and galvanising responses at the local level. Meanwhile, provincial governments have been able to leverage climate plans and actions to achieve their own gains. These findings suggest that any optimism about subnational climate activism in a Chinese setting has to be mixed with caution. In fact, the shadow of hierarchical authority structure lingers and plays important part in the initiation of subnational response and spurring climate responses and innovations from below. [ABSTRACT FROM AUTHOR]

Recent interpretations of the archaeology of domesticated rice evolution and the development of agriculture in the Lower Yangzi Valley are being informed by new genetic, palaeoenvironmental, archaeological and archaeobotanical data. This paper explores current views on early rice production in the region and attempts to expand the discourse to provoke exploration of new and modified questions. Rice-specific botanical through large-scale ecological issues and causality are examined. This paper argues that understanding rice domestication and production, although important, should not be the exclusive goal of research on early agriculture in the Yangzi Valley. Despite the preliminary nature of the investigations at Kuahuqiao (c. 8000–7000 cal. BP), evidence of resource management, and potential domesticated resources or their ancestors that includes pig (Sus scrofa), peach (Prunus persica), apricot (P. armeniaca), Japanese apricot (P. mume), foxnut (Euryale ferox) and water chestnut (Trapa spp.) underscore the need to broaden the scope of inquiry on early food/resource production. The complexities of the archaeological and environmental record in the Yangzi valley indicate that nuanced, complex explanations for rice domestication and agricultural origins rather than deterministic, single cause explanations are necessary in order to move forward. [ABSTRACT FROM AUTHOR]

Recently, increasing nutrient (i.e., nitrogen and phosphorus) concentrations have been observed in the surface water of many countries and this nonpoint source (NPS) pollution has become an important factor in the deterioration of water quality in the upper reach of the Yangtze River Basin. In this paper, the NPS pollution loads in the upper reach of Yangtze River Basin in the year 2000 were estimated using export coefficient model and remote sensing techniques. The spatial distributions of the NPS loads within the watershed were then displayed using geographical information system. Results indicated that the total nitrogen load was 1.947×106 t and the total phosphorus load was 8.364×104 t. Important source areas for the nutrients were croplands in the Jinsha R. and Jialing R. watershed, as well as the Chongqing municipality. [ABSTRACT FROM AUTHOR]

Hedgerow intercropping systems were introduced in China in early 1990s. Achievements in research and extension of contour hedgerow intercropping in China during the past 15 years are reviewed here. Results reported in over 70 published papers have shown that hedgerow intercropping contributes to soil and water conservation, soil fertility amelioration, land productivity improvement, bioterrace formation, and gives more options for income generation based on local resources in mountain areas. Research and demonstration works on contour hedgerow systems have achieved success by integrating local resources and needs into the system, especially in the dry valleys of the upper reaches of the Yangtze River, and the Three Gorges region. Contour hedgerow intercropping has attracted the attention of researchers, policy-makers, and farmers, and has been taken as an alternative to implementation of the Grain for Green policy, and ecological reconstruction and restoration today. To date, hedgerow intercropping has been demonstrated and applied practically on sloping land in more than six provinces of China, particularly Sichuan, Guizhou, Shanxi, Shaanxi, as well as in the Three Gorges region of Chongqing and Hubei Province. The intercropping system has also been practiced as an optimized technology for conserving farming on sloping lands, improving cash income, and reducing agricultural risks in depressed mountainous regions in southwest and northern China over recent years. Some misunderstandings and problems in studies and extension of the system in China are summarized and clarified, and some recommendations for further research and expansion of the system are also presented in this paper. [ABSTRACT FROM AUTHOR]

Water footprint of production can be used to identify pressure on national or regional water resources generated by production activities. Water stress is defined as the ratio of water use (the difference between a regional water footprint of production and a green water footprint) to renewable water resources available in a country or region. Water stress can be used to identify pressure on national or regional water resources generated by production activities. This paper estimates the water footprint of production and the water stress in China during the years 1985-2009. The result shows that China's water footprint of production increased from 781.58 × 109 m3 in 1985 to 1109.76 × 109 m3 in 2009. Mega-cities and regions with less agriculture production due to local climatic conditions (Tibet and Qinghai) had lower water footprint of production, while the provinces (Henan, Shandong) with higher agriculture production had higher footprint. Provinces with severe water stress increased from 6 in 1985 to 9 in 2009. High to severe water stress exists mainly in mega-cities and agricultural areas located in the downstream areas of the Yellow River and the Yangtze River in North and Central China. The outlook for water resources pressure in China is not optimistic, with areas of stress expanding from northern to southern of China. [ABSTRACT FROM AUTHOR]

By Hirschman-Herfindahl Index, the paper measures the spatial structure transformation of the Chinese container port system from the perspective of cargo flow in recent 13 years. It indicates that the spatial structure of container port system enters into 'the challenge of the periphery' phase as a whole, the decentralization of container flow become the mainstream tendency of the spatial variation of China's container port system; on the other hand, the spatial structure of container port system shows different characteristic in seven port regions, such as low-level equilibrium, single-gateway, multi-gateway and so on. It is a fact that multi-gateway port region of container port system has formed in Yangtze River Delta and Pearl River Delta region. Economic and foreign trade development, government macro-control and policy guidance, challenge of the periphery, network expansion of the terminal operators and shipping liners are the main driving forces for these new phenomena. [ABSTRACT FROM AUTHOR]

The flow regime of the Yangtze River (Changjiang) has been altered to some extent by intensified human activities over the past decades, particularly dam construction. To assess the impacts of dam building on the flow regime in the Yangtze River, two of the largest reservoirs on the upper reach, i.e., the Gezhouba and Three Gorges reservoirs, have been selected as case study sites. To analyze the changes in flow regime between predam and postdam periods, the whole study period was divided into three subperiods according to the years when these two reservoirs started to store water. On the basis of the time series of daily flow discharge from four key hydrological stations, i.e., Cuntan, Yichang, Hankou, and Datong, the alterations in annual, seasonal, monthly, and daily flow regimes and water rising or falling regime in different subperiods were investigated and the driving forces were explored. The results revealed the impacts of the two reservoirs on their downstream flow regime varied with reservoir storage capacity and the distance between the target reservoir and the case study site, the Gezhouba and Three Gorges reservoirs imposed various impacts on different time scales of downstream runoff regime, and the operation of these two reservoirs altered the water rising and falling regime to some degree, which is particularly critical for the spawning of Chinese sturgeon and the four major domestic carp. The output of the paper could provide references for the assessment of impacts of dam construction on the health and stability of the Yangtze River ecosystem. [ABSTRACT FROM AUTHOR]

Poyang Lake in Jiangxi Province is the largest freshwater lake in China and is historically a region of significant floods. Maximum annual lake stage and the number of severe flood events have increased during the past few decades because of levee construction that reduced the area available for floodwater storage. The most severe floods since 1950 occurred during 1954, 1973, 1983, 1995, and 1998. Each of these floods followed El Niño events that influence the Asian monsoon and that are directly linked to rainfall in the Changjiang (Yangtze River) basin. The 1954 flood was the largest ever recorded until the 1990s. That year the peak Changjiang stage at Hukou was 21.6 m, which was 1.6 m above the previous record high. The last major flood on the Changjiang was during 1998, when the peak Changjiang stage reached 22.5 m, higher than during 1954, even though peak discharge was lower. The most severe floods, including those in 1954 and 1998, require both 1) high rainfall and tributary discharge into Poyang Lake and 2) high Changjiang discharge and stage at Hukou that backflows into the lake or slows Poyang Lake drainage. Since gauging stations were established on the Changjiang, these conditions always occurred following an El Niño. [ABSTRACT FROM AUTHOR]

China is entering a critical and accelerating phase of urbanization. As one of the most urbanized regions in China, the Changjiang (Yangtze) River Delta has experienced dramatic urbanization and urban transformation. However, in the recent years, many changes have taken place in this region and there is limited attention to the regional urbanization path evolution, its problems and the way to solve these problems. Therefore, we should revisit the urbanization process in the Changjiang River Delta again. In this paper, we revisited urbanization paths of the Changjiang River Delta by data analysis, influence factors of urbanization by the Gray Relational Analysis, and major challenges to urbanization of the Changjiang River Delta by theoretical considerations. We found that the urbanization of the Changjiang River Delta had experienced several stages of large-scale spatial and urban system restructuring. Within the Changjiang River Delta, Shanghai, Zhejiang and Jiangshu had experienced different urbanization path with local characteristics. But with their development model gradually converging, their urbanization model is also converging. We also found that the major influence factors affecting the Changjiang River Delta urbanization were dynamic change and urbanization was driven by different key factors in different socio-economic development stages. Meanwhile, the Changjiang River Delta urbanization is facing many problems such as existing institutional arrangements, including the hukou (household registration) system and others which can not meet the needs of current socio-economic development and urbanization. Therefore, it is imperative to promote institutional innovation and adopt a new urbanization development strategy for the sake of the orderly and sustainable urbanization development in the Changjiang River Delta. [ABSTRACT FROM AUTHOR]

The formation and geomorphic evolution of the Jiuduansha Shoal are investigated over the past 50 years in this paper. The sedimentary processes, formation, and geomorphic evolution of the Jiuduansha Shoal in the Yangtze River Estuary, eastern China, are analyzed based on digitized sea maps from 1945 to 2001, satellite images from 1975 to 2001, and field survey data in the spring-neap tidal cycle in the dry and flood seasons in 2003. The suspended sediment concentration and hydrodynamics of the North Passage and South Passage during the dry and flood seasons in the spring-neap tidal cycle in 2003 were investigated, and relations between the North Passage and South Passage of the Jiuduansha Shoal are analyzed. Results show that seasonal and spring-neap tidal cycle variations in sediment and water discharge from the drainage basin correspond to erosion and deposition on the Jiuduansha Shoal. The results and data can provide useful information for the management of the Yangtze River Estuary and restoration of the estuarine tidal flat ecology. [ABSTRACT FROM AUTHOR]

This paper is a response, both to Fuller et al.'s recent criticism of Chinese research on rice domestication, as lacking evidence, and to their argument for the beginning of rice domestication around 4000 BC in the lower Yangzi River. We first survey previous publications that discuss the process from wild rice collection to rice domestication in China, and then examine early rice remains from the perspectives of rice morphology and archaeological context. We focus on three aspects: the timing of the initial rice domestication in the Yangzi River region; the earliest presence of domesticated rice in the Lower Yangzi and Huai River regions; and the implications of changes in rice grain sizes in archaeological assemblages. We also discuss problems relating to the presence of immature rice remains in the archaeological record, grain size increase and overall grain shape, which are three of the criteria used by Fuller et al. for distinguishing domesticated from wild rice. Based on published data and our research on rice, we demonstrate that by the early Holocene (9000 cal. BP), Neolithic people in both north and south China may have been harvesting wild rice and initiating rice cultivation that eventually led to domestication. [ABSTRACT FROM AUTHOR]

The lower Yangtze, eastern China, was colonized by several Neolithic and Bronze Age cultures giving rise to possibly the highest concentration of prehistoric sites in the world. Early Neolithic cultures in the delta region cultivated rice (Oryza sativa) and agricultural developments appear to have occurred throughout the Neolithic with abrupt socio-economic changes possibly associated with the terminal Neolithic. Given the extensive history of environmental exploitation and well-preserved archaeological sites, the Yangtze delta is an ideal setting to explore the complex interactions between humans and their environment. Multiproxies of environmental changes, namely pollen, charcoal and phytoliths, in a 14C AMS-dated sequence of sediments from an exposed profile at Qingpu, Yangtze delta, were investigated. 14C AMS dating indicates that the age range of the sedimentary sequence analysed is from c. 1800 to 6000 BP, and therefore encompasses the terminal Neolithic and subsequent Bronze Age in the region. This paper reviews this sediment-based evidence in the light of current understanding of human-environment interactions during a critical phase of the development of the Yangtze delta and associated human cultures. [ABSTRACT FROM AUTHOR]

Applying a parameterized directional distance function approach, this paper estimates the regional eco-efficiency and pollutants' marginal abatement costs in China based on provincial panel data covering the years 2003–2012. We find that China could potentially save capital, labor, land, energy and water by 18.07%, 11.47%, 11.20%, 12.28% and 11.19%, and reduce emissions of carbon dioxide (CO 2 ), household refuse and waste water by 11.75%, 11.02% and 11.46%, respectively, on condition that all provinces produced fully efficiently, The south and east coastal areas were the most eco-efficient, while the middle Yangtze River and southwest areas performed relatively poor. For the whole country, the average shadow prices of CO 2 , household refuse and waste water were 717.27 Yuan/tonne, 42,936.98 Yuan/tonne and 306.65 Yuan/tonne, respectively. The shadow price of CO 2 revealed significant regional disparities and that of household refuse showed a rapid increase throughout the study period. Our estimates suggest that policymakers should take measures to avoid ineffective capital investment and improve economic output efficiency in inland provinces, especially in the middle Yangtze River, northwest and southwest areas, and facilitate technological cooperation between developed and undeveloped areas. The regional heterogeneity and flexible price mechanism of various pollutants should be taken into consideration when making the reduction allocations among different areas. [ABSTRACT FROM AUTHOR]

Abstract: This study aims to investigate whether, to what extent and how a transition toward integrated flood management has taken place in the Dongting Lake area at the middle Yangtze. Accordingly, we conducted a longitudinal research of its flood management (1949–2009). We developed an analytical framework linking regime components to two societal learning types (double and triple-loop learning) that are key to a regime transition. Our study shows that the transition toward integrated flood management has already started, but the whole regime transformation will still take time to complete, due to, for example, the not-yet-ready decision-making processes that shape the structure changes as well as the incompatibilities between what is on paper and real implementation. To understand how the regime transition took place, we investigated where and how triple-loop learning was initiated as well as how so-called “informal learning processes” has contributed to the transition of Dongting flood management. [Copyright &y& Elsevier]

This paper examines the role of the World Wildlife Fund for Nature China as policy entrepreneur in China. It illustrates the ways in which the World Wildlife Fund for Nature is active in promoting integrated river basin management in the Yangtze River basin and how the efforts at basin level are matched with the advice of the China Council for International Cooperation on Environment and Development task force on integrated river basin management to the national government of China. This article demonstrates that the World Wildlife Fund for Nature uses various strategies of different types to support a transition process towards integrated river basin management. Successful deployment of these strategies for change in environmental policy requires special skills, actions, and attitudes on the part of the policy entrepreneur, especially in China, where the government has a dominant role regarding water management and the position of policy entrepeneurs is delicate. [ABSTRACT FROM AUTHOR]

Copyright of Knowledge & Management of Aquatic Ecosystems is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Diverse and well-preserved latest Permian phytoplankton assemblages are described from four sections of the Yangtze Block, South China from localities in Zhongzhai (Guizhou Province), Shangsi (Sichuan Province), Xiakou (Hubei Province) and Dongpan (Guangxi Province). Most of the species have been reported previously from other upper Permian sections worldwide. The South Chinese phytoplankton taxa are generally very small in size, usually displaying diameters of about 20 μm and commonly include the generaMicrhystridium,VeryhachiumandLeiosphaeridia. However, larger taxa with vesicles often exceeding 80 μm in diameter, such asDictyotidium, are also abundant in the Shangsi section. Due to the presence of large populations ofMicrhystridiumandVeryhachium, a simple classification scheme for theMicrhystridium/Veryhachiumcomplex is proposed, based on the geometrical shape of the vesicle. We propose dividing the complex into five groups: theVeryhachium cylindricumgroup, representing all ellipsoidal specimens; theVeryhachium trispinosumgroup, all with triangular-shaped vesicles; theVeryhachium lairdiigroup, all with rectangular forms; theMicrhystridium pentagonalegroup, all with pentagonal specimens; and theMicrhystridium brevegroup, which includes all spherical forms. [ABSTRACT FROM PUBLISHER]

Background: Phlebotomus chinensis is a primary vector of visceral leishmaniasis; it occurs in various biotopes with a large geographical distribution, ranging from Yangtze River to northeast China. Phlebotomus sichuanensis, a species closely related to P. chinensis in high altitude regions, has a long term disputation on its taxonomic status. Both species occur in the current epidemic regions and are responsible for the transmission of leishmaniasis. Population genetic analysis will help to understand the population structure and infer the relationship for morphologically indistinguishable cryptic species. In this study, microsatellite markers were used for studying the genetic differentiation between P. chinensis and P. sichuanensis. Methods: Sandflies were collected in 6 representative localities in China in 2005-2009. Ten microsatellite loci were used to estimate population genetic diversity. The intra-population genetic diversity, genetic differentiation and effective population size were estimated. Results: All 10 microsatellite loci were highly polymorphic across populations, with high allelic richness and heterozygosity. Hardy-Weinberg disequilibrium was found in 23 out of 60 (38.33%) comparisons associated with heterozygote deficits, which was likely caused by the presence of null allele and the Wahlund effect. Bayesian clustering analysis revealed three clusters. The cluster I included almost all specimens in the sample SCD collected at high altitude habitats in Sichuan. The other two clusters were shared by the remaining 5 populations, SCJ in Sichuan, GSZ in Gansu, SXL and SXX in Shaanxi and HNS in Henan. The diversity among these 5 populations was low (FST = -0.003-0.090) and no isolation by distance was detected. AMOVA analysis suggested that the variations were largely derived from individuals within populations and among individuals. Consistently, the analysis of ribosomal DNA second internal transcribed spacer (ITS2) sequence uncovered three types of variants, which corresponded with the three gene pools revealed by microsatellites. Conclusions: The data suggested that the SCD population carried a distinct gene pool, which was differentiated from the other populations. The high altitude ecological habitats, distinctive ITS2 and herein divergence inferred by microsatellite loci support the species status of P. sichuanensis. The P. chinensis populations did not have a significant divergence from each another. [ABSTRACT FROM AUTHOR]

Water resources and soil erosion are the most important environmental concerns in the Yangtze River basin, where soil erosion and sediment yield are closely related to rainfall erosivity. The present study explores the spatial and temporal changing patterns of the rainfall erosivity in the Yangtze River basin of China during 1960-2005 at annual, seasonal and monthly scales. The Mann-Kendall test is employed to detect the trends during 1960-2005, and the T test is applied to investigate possible changes between 1991-2005 and 1960-1990. Meanwhile the Rescaled Range Analysis is used for exploring future trend of rainfall erosivity. Moreover the continuous wavelet transform technique is using studying the periodicity of the rainfall erosivity. The results show that: (1) The Yangtze River basin is an area characterized by uneven spatial distribution of rainfall erosivity in China, with the annual average rainfall erosivity range from 131.21 to 16842 MJ mm ha h. (2) Although the directions of trends in annual rainfall erosivity at most stations are upward, only 22 stations have significant trends at the 90 % confidence level, and these stations are mainly located in the Jinshajiang River basin and Boyang Lake basin. Winter and summer are the seasons showing strong upward trends. For the monthly series, significant increasing trends are mainly found during January, June and July. (3) Generally speaking, the results detected by the T test are quite consistent with those detected by the Mann-Kendall test. (4) The rainfall erosivity of Yangtze River basin during winter and summer will maintain a detected significant increasing trend in the near future, which may bring greater risks to soil erosion. (5) The annual and seasonal erosivity of Yangtze River basin all have one significant periodicity of 2-4 years. [ABSTRACT FROM AUTHOR]

Outward expansion of urban lands in the developing nations is often associated with a substantial loss of environmental resources such as forests, wetlands, freshwater and cash crop fields. Yet, determining how different aspects of urbanisation – such as city population size and spread pattern of built-up lands – contribute to the cumulative loss of resources remains controversial. In this study, data sets were constructed describing changes to land cover across 65,200 grid cells at 1 km2 spatial resolution for China's Changjiang Delta Region over the past 60 years. The results showed that the region lost 12.2% of total resource sites. The distribution of resource degradation showed a highly dispersed pattern and was not confined to a few intense areas associated with large cities. No empirical evidence was found that city population size alone accurately predicts the distribution of resource loss. Very large cities (N = 4) contributed 35% to the total loss, demonstrating impacts similar to those of much more scattered towns (N = 230). Urban expansion of large cities may lead to extensive resource loss; however, a set of non-linear mechanisms, such as the diminishing effects of per-unit area urban spread on resources and interactions between urban patterns and the size of urban spread, can also play a significant role in downsizing the negative effects of large cities on resource sites. Thus, effective urban policies should carefully weigh the cumulative urban spread mechanisms of both large and small cities responsible for spatially dispersed degradation of environmental resources. [ABSTRACT FROM AUTHOR]

In this study, the applicability of the statistical downscaling model (SDSM) in downscaling precipitation in the Yangtze River basin, China was investigated. The investigation includes the calibration of the SDSM model by using large-scale atmospheric variables encompassing NCEP/NCAR reanalysis data, the validation of the model using independent period of the NCEP/NCAR reanalysis data and the general circulation model (GCM) outputs of scenarios A2 and B2 of the HadCM3 model, and the prediction of the future regional precipitation scenarios. Selected as climate variables for downscaling were measured daily precipitation data (1961-2000) from 136 weather stations in the Yangtze River basin. The results showed that: (1) there existed good relationship between the observed and simulated precipitation during the calibration period of 1961-1990 as well as the validation period of 1991-2000. And the results of simulated monthly and seasonal precipitation were better than that of daily. The average R values between the simulated and observed monthly and seasonal precipitation for the validation period were 0.78 and 0.91 respectively for the whole basin, which showed that the SDSM had a good applicability on simulating precipitation in the Yangtze River basin. (2) Under both scenarios A2 and B2, during the prediction period of 2010-2099, the change of annual mean precipitation in the Yangtze River basin would present a trend of deficit precipitation in 2020s; insignificant changes in the 2050s; and a surplus of precipitation in the 2080s as compared to the mean values of the base period. The annual mean precipitation would increase by about 15.29% under scenario A2 and increase by about 5.33% under scenario B2 in the 2080s. The winter and autumn might be the more distinct seasons with more predicted changes of precipitation than in other seasons. And (3) there would be distinctive spatial distribution differences for the change of annual mean precipitation in the river basin, but the most of Yangtze River basin would be dominated by the increasing trend. [ABSTRACT FROM AUTHOR]

Known as the four famous carps in China, black carp ( Mylopharyngodon piceus), grass carp ( Ctenopharyngodon idella), silver carp ( Hypophthalmichthys molitrix) and bighead carp ( Hypophthalmichthys nobilis) are commercially important fish species with a high production in China. To reveal the relationships between meteorological conditions and the natural spawning behavior of these fishes, we considered six meteorological factors (including wind, rainfall, temperature, air pressure, sunshine hours and humidity) and the weather conditions in 80 spawning events. The results showed that the spawning activities were more likely to be activated in consecutive rainy days or days when weather changed drastically, while the spawning activities showed no tendency for the weather type except consecutive rainy days. Our analyses also showed that the average rainfall in the initial spawning days is higher than that in the spawning time windows (the time from the earliest spawning activity to the latest spawning activity), while other meteorological elements remained at more or less the same values in both time periods; spawning activity tended to happen in days when the average air pressure was going down or the average temperature going up, while the other meteorological elements showed no consistent tendency. [ABSTRACT FROM AUTHOR]

Copyright of Hydrological Sciences Journal/Journal des Sciences Hydrologiques is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The effects of the sediment regime on the flood level in the middle reach of the Yangtze River before and after the construction of the Three Gorges Dam (TGD) are investigated. Before the dam construction, the sediment regime has driven the flood level higher and higher over recent decades in the middle reach of the Yangtze River, which has reflected changes in the location and amount of sediment deposition. After dam completion, the magnitude and rate of channel degradation determines the process of flood stage lowering but they are difficult to estimate owing to insufficient understanding of the sediment discharge recovery process. To make a rational prediction of channel degradation of the Yangtze River downstream from the TGD, the sediment transport rate during channel degradation downstream from other dams is examined. It is found that, for any grain size, postdam sediment transport rates cannot exceed the predam level at any location along the downstream channel. Erosion amounts predicted for the reach downstream from the TGD before its closure are too high. In light of this, a numerical simulation of the channel degradation process is carried out. The results indicate that, although degradation takes place immediately after the TGD closure, the flood level in the middle reach of the Yangtze River will still remain at its predam condition in the following 20 years. This is determined not only by the regional characteristics of the middle reach of the Yangtze River but also by the common law of sediment transportation downstream from dams. [ABSTRACT FROM AUTHOR]

Land use/cover change (LUCC), which results from the complex interaction of social, ecological and geophysical processes, is a major issue and the main cause of global environmental change. This study analyzed the land use/cover dynamics and their environmental and socio-political forces in the upper reaches of the Yangtze River from 1980 to 2000 by using remote sensing, climatic and socio-economic data from both research institutes and government departments. The results indicated that there had been significant land use/cover changes between 1980 and 2000 in the study area, which were characterized by a severe replacement of cropland and woodland with grassland and builtup land. The transition matrices highlight the dominant dynamic events and the internal conversions between land use/cover types during the study period and reveal two distinct transition phases. Land use/cover changes in the upper reaches of the Yangtze River during 1980 to 2000, while restricted by environmental attributes, were strongly driven by socio-political factors. However, excessively pursuing higher land use benefits likely results in serious environmental degradation. This study suggests that the restructuring of land use should be based on land suitability and sustainable protection of fragile environment in the upper reaches of the Yangtze River. A thorough comprehension of historical changes will enhance our capability to predict future land use change and contribute to effective management strategies and policies for the rational land use. [ABSTRACT FROM AUTHOR]

In the source regions of the Yangtze and Yellow Rivers of China, glaciers, frozen ground, the hydrological system, and alpine vegetation have changed over the past decades years. Climatic causes of these variations have been analyzed using mean monthly air temperature and monthly precipitation between 1956 and 2000, and monthly evaporation from φ20 evaporation pans between 1961 and 1996. In the source region of the Yangtze River, lower temperature and plentiful precipitation during the 1960s and continuing into the early 1980s triggered a glacier advance that culminated in the early 1990s, while a robust temperature increase and precipitation decrease since 1986 has forced glaciers to retreat rapidly since 1995. Permafrost degradation is another consequence of the climatic warming. The variations in the hydrological system and alpine vegetation are controlled mainly by the climate during the warm season. Warmer and drier summer climate is the major cause of a degradation of the vegetation, desiccation of the high-cold marshland, a decrease in the areas and numbers of lakes and rivers in the middle and north source regions of the Yangtze and Yellow Rivers, and a reduction in surface runoff in the source region of the Yangtze River for the last 20 years. The causes of eco-environmental change in Dari area, near the outlet from the source area of the Yellow River, are different from those elsewhere in the study area. A noticeable reduction in runoff in the source region of the Yellow River and degradation of alpine vegetation in Dari area are closely related to the permafrost degradation resulting from climate warming. [ABSTRACT FROM AUTHOR]