Based on nonagricultural population data from 1986 to 2007,by using qualitative analysis and various quantitative methods such as scalerank law,ROXY law and so on,this paper systematically analyzed temporalspatial characteristics of the evolution of urban system in the Yangtze River Delta,in view of two core issues in development of urban system:grade scale structure,spatial structure.The results showed that:urban agglomeration was in the trend of decentralization，the number of mediumsized cities increased significantly,and the nonagricultural population concentration of gravity gradually transferred from the traditional big cities to the small and mediumsized cities.Shanghai was the key city in the region.It played a leading role in the regional development,and influenced far beyond the scope of the region.Took Shanghai as the center,Nanjing,ShanghaiHangzhou,the Yangtze River as the axis to form the remarkable significant layer structure,Xinghua,Gaoyou,western region of Hangzhou,Taizhou were less affected by big cities.ShanghaiSuzhouWuxi formed the “urban area” of close internal linkages and fuzzy hierarchy,which was “core area” of the Yangtze River Delta and advanced form of continuous development of urban.Despite the lack of scale advantages in the secondtier cities,Nanjing and Hangzhou played a prominent role in the region due to their location,that is,actually take the role of the regional subcenter.Around the core area and two vice center,the Yangtze River Delta built a “>” type of urban development spindle

In recent years,nationwide highspeed rail network construction has been becoming the focus of public concern.Highspeed rail is extremely popular with its obvious advantages:fast speed,large transmission capacity,good security,comfort and convenience,less energy consumption,good economic returns,etc.With the building of “four vertical and four horizontal” passenger special line in full swing,our country will step into the highspeed rail age.Highspeed rail shortens the travel time and distance of people,goods and information flow.And highspeed rail opens an era of economic circle.Therefore,the approach of the highspeed rail era is bound to have a farreaching influence and significance to the region.Highspeed rail will accelerate and amplify city effect of the urban economic circles,and change the producer type of people,way of life;Highspeed rail will speed up regional integration and mutual winwin of central cities leading;Highspeed rail will promote upgrading of industry,for example,tourism and real estate,and promote redistribution of city planning along the line;Highspeed rail will cause recombination of 〖JP2〗“aviation,land transportation and waterway” three modern transportation means,bring about diversification of the way people travel

Relationship between resource use and economic growth is the important field of resources and environmental economics studies.The paper attempts to integrate Material Flow Analysis (MFA) approach and the newly developed autoregressive distributed lag (ARDL)bounds testing approach to examine the relationship between resource use and real GDP for Tongling City of Anhui Province,during the period of 1990~2008.The direct material input (DMI),one of subaccounts of MFA,is also used as the proxy variable of resource use.The results of the bounds test indicate that a longrun cointegration relationship exists between the proxy of resource use and the explanatory variable:economic growth.The longrun parameters are estimated through a longrun static solution of the estimated ARDL model,and then the shortrun dynamics are estimated by the error correction model.The study also indicates the existence of shortrun and longrun causality running from resource use to economic growth.The findings imply that resource use is a stable forcing variable for economic growth in Tongling City.The estimation results are also of policy implication on economic development and resource conservation strategies for Tongling City

In the operation of Middle Route of South to North Water Transfer Project,series of compensation project will be sketched up,namely,the Xinglong Pivot,water transferring from the Yangtze River to the Hanjiang River,channel improvements and some lock station reconstruction,etc.in order to mitigate disadvantageous influences on the middle and lower reaches of the Hanjiang River caused by water transfer project.After the operation of these compensation projects,not only the hydrological conditions in lower reaches of the Hanjiang River and the river compositions in Hubei will be changed,but also a new manner of water transportation in lower reaches of the Hanjiang River will appear.That is to say,on one hand,we can improve navigating capacity in a certain extent;on the other hand,new channels will be established in lower reaches of the Hanjiang River.That has brought new influence on the economic development of the region along river.Jingmen City is located in the joining place of middle and lower reaches of the Hanjiang River.Aiming at the opportunity of developing water transportation and the existing problems of Hanjiang water transportation,effective countermeasures should be taken to expand water transportation in the Hanjiang River in order to construct the new pivot point of economic development of Jingmen City

Agricultural functions zoning is the base for accurately positioning a county’s agriculture function orientation,promoting the prolongation of regional agricultural additional functions,and promoting traditional agriculture evolving to modem agriculture pattern.The paper is aimed at trying to accomplish the agricultural functional zoning of Hubei Province by using the constellation clustering analysis.Analyzing modern agriculture function orientation from four aspects of production supply,employment and social security,ecological system adjustment,and cultural inheritance and leisure,the paper established the agriculture functional zoning index system of Hubei Province that contained thirty quantitative indices and two qualitative indices.Using the constellation clustering analysis,the paper determined the single function classification type of each county or city according to each star's location.And then,considering the geographical position,socioeconomic and environmental status of the zoning units.The paper worked out the agricultural functions zoning scheme of Hubei Province.The zoning units were county administrative regions.According to the basic principles of agricultural functional zoning,Hubei Province was divided into four agricultural dominant function zones and twelve secondary agricultural functional areas that each dominant function zone contained three secondary agricultural functional areas. 

According to ratoon rice growth and yield formation with meteorological conditions in the southeast of Sichuan basin，light and heat conditions are the main climatic factors which influence the growth period of ratoon.The main meteorologic problems which influence the ratoon most are the continuous low temperature overcast and rainy day during the flowering stage or the high temperature and drought during the germination of dormant buds stage.Based on the analysis beforehand,the article selected accumulated temperature and sunshine duration during the growth of ratoon as the key indices of climatic types,which have significantly different spatial distribution by terrain and have the great influence on the ratoon growth and yield formation.The sunshine and heat resources adaptive regionalization of ratoon rice was made based on the spatial distribution of indices which was made based on the GIS and 1:250,000 DEM.The area suitable for cultivation were divided into four types based on the analysis.They were the region rich in heat and light,the region rich in heat and relatively rich in light,the region rich in light and relatively rich in heat,and the region relatively rich in light and heat.And characters of climate resources and meteorological disasters were also described by types too.Based on the above,the paper put forward the cultivation methods to increase production and the ways to develop ratoon with other late autumn crops in order to develop the ratoon rice more stable and reliable

Based on previous studies,the characteristics of saltwater intrusion of the South Branch of the Changjiang Estuary were studied systematically by the analysis of measured saltwater intrusion and chlorinity data.Results indicate that the saltwater which spills over from the North Branch is the main source of the salt intrusion of the South Branch.In the study area,the distribution of chlorinity during dry season’s spring tide appears as a twosidehigh and middlelow’s saddle shape,while the distribution of chlorinity during dry season’s middle tide appears as a highlowhighlowhigh’s ‘W’ shape.Because of the effects of tide and upstream’s discharge,the distribution shape of chlorinity has varied from spring tide to middle tide.The intensity of the salt intrusion of the South Branch tends to be much more serious since 1998;the salt intrusion of the South Branch is much more serious during February and March than other months;the salt intrusion of the South Branch may take place when the discharge from Datong station is less then 20 000 m3/s.There are close relationships between discharge from Datong station and tidal strength;larger the discharge,lower level of the salt intrusion;greater the tidal range,higher level of the salt intrusion

The Yangtze River estuary is one of the largest estuaries in the world. Baimaosha, Biandansha, Zhongyangsha, Jiuduansha and Chongming island have been formed by rapid sedimentation in different stages of the estuary development. As sedimentation has progressed, there are associated changes in organic carbon content in the surface sediments. Few previous research has been completed on organic carbon concentrations in surface sediments of the estuary islands in relation to the growth of the island wetlands. This research investigated the concentrations of organic carbon within surface sediments of the wetland island progressing to land. Results showed that the carbon content in the surface sediments increased when the island wetlands progressed to land. The most recent formed wetland island had a low organic carbon content, such as Baimaosha, 1057%; with the development of the island wetlands to land, the organic carbon content increased gradually, such as the sediments in east beach of Chongming island, had a concentration of 3176%. In addition, the organic carbon content increased gradually with the increase in altitude. The highest concentrations were in the reed zone, 3004%; the lowest were in bare beach region, 1436%; the concentrations of 〖WTBX〗Scirpus mariqueter〖WTBZ〗 zone were between them, 1812%. However, the organic carbon content became uneven when the island wetlands was developing to land, which also explained the changing law of the organic carbon content in the surface layer of the island wetlands development. The study indicates that the island wetlands in estuary play an important role in storing organic carbon when processing to land

Smooth cordgrass,〖WTBX〗Spartina alterniflora〖WTBZ〗 Loisel.,a perennial rhizomatous grass native to the Atlantic and Gulf coasts of North America,has invaded into many estuaries and coastal salt marshes in China in the past 20 years.Chongming Dongtan(“Dongtan” in abbreviation),the wetland of international importance,which provides important stopover sites for migratory birds on East AsianAustralasian Flyway,has been suffering from 〖WTBX〗S. alterniflora〖WTBZ〗 invasions in the recent 15 years,and the structures and functions of the wetland ecosystem were severely threatened.〖WTBX〗S.alterniflora〖WTBZ〗 was first recorded in Dongtan in 1995 and kept expanding rapidly in the latter decade.The 〖WTBX〗S.alterniflora〖WTBZ〗 communities covered 1 600 hm2 by 2005,which distributed dominantly in the northern and eastern marshes in Dongtan.Based on recent studies,this paper illustrated the mechanisms of successful invasions of 〖WTBX〗S.alterniflora〖WTBZ〗.According to the physiological characteristic of 〖WTBX〗S.alterniflora〖WTBZ〗 and the hydrological characteristic of Yangtze River mouth,it can be concluded that:1)〖WTBX〗 S.alterniflora〖WTBZ〗 would keep expanding in the northern and eastern Dongtan;2) It would be difficult to be invaded for 〖WTBX〗S.alterniflora〖WTBZ〗 in southern Dongtan;3) Human activities would facilitate 〖WTBX〗S.alterniflora〖WTBZ〗 invasions.Consequently,proper management and control of 〖WTBX〗S.alterniflora〖WTBZ〗 should be carried out urgently

Based on TM (30m) data in 1987,1995,2000 and 2006,the characteristics and comprehensive evaluation of land use dynamics of different reclamation time on the northern Hangzhou Bay were analyzed with the method of spatial sere substituting for time sere and Principal Component Analysis (PCA).A comprehensive evaluation model of land use dynamics in the study has been established and verified with land use change data of Nanhui reclamation zones.Conclusions showed:(1) Land use level comprehensive index (L) tended to linearly increase （〖WTBX〗R2〖WTBZ〗=0457 7）with the increase of reclamation time. Land use diversity (GM) also tended to increase,and reached a steady state between 35 and 40 years.(2) Change of agricultural land positively correlated with the comprehensive evaluation index（paddy field>greenhouse>farm land>forest>orchard）,while nature dominated land types (breeding pond>grass land>open water>mud flat) negatively correlated with the Fvalue.(3) Fvalue tended to increase (〖WTBX〗R2=0.511 9〖WTBZ〗) with the increase of reclamation time,and reached a steady state after about 40 years of reclamation.Regression analysis showed that Fvalue reflected the information of land use degree index (L) and diversity index (GM) well.(4) Land use dynamic was impacted by following driving force factors:anthropological factors>natural factors

Heavy metal concentrations and basic properties including pH values,particle size and content of organic matter were analyzed in a total of 90 street dust samples collected in July,2003 and April,2004 from three small towns in Shanghai suburban area.The results showed that the three different small towns presented similar temporal and spatial distribution characteristic for pH,particle size and organic matter as well as heavy metals.The pH values of the street dust were 841~1137,which assume alkaline.The average content of organic matter in street dust was 3413 g/kg.The street dust had coarser particle size than soil around,and the average particle size was 1736 μm.Sand grain was the main particles in street dust with the average volume fraction 70%.The particle size of street dust mainly showed unimodal or bimodal distribution spectrum,where the first mode was 250~300 μm,and the second was 30~50 μm.The average heavy metal concentrations were much higher than the soil background values of Shanghai city,but lower than those of Shanghai urban area.Cr and Ni concentrations showed significant seasonal change,which were higher in July (summer) and lower in April (spring).Higher concentrations of Cd,Cu,Pb and Zn were distributed mainly in the towns residential area,commercial area and scenic area as well as the township roads than in rural area.The prominent correlation between Cr and Ni,Cu and Pb,Cu and Zn,Pb and Zn,Fe and Mn might suggest the two possible sources of heavy metals in street dust;one might be related to vehicle transportation,and the other might be natural source such as soil.Moreover,significant correlation between organic matter and heavy metals indicated that organic matter was the carrier of heavy metals in street dust

During the seasonal investigation on the snail  community in the tributaries(TRIB),western basin(WB),middle basin(MB),eastern basin(EB),and culturing enclosures of Chinese mitten crab(〖WTBX〗Eriocheir sinensis〖WTBZ〗)(CEES)of Yangcheng Lake,Jiangsu province from Jan.2008 to Oct.2009,six snail species belonging to 5 genus,4 families were recorded,in which 〖WTBX〗Bellamya aeruginosa〖WTBZ〗 was predominant,and 〖WTBX〗Alocinma longicornis〖WTBZ〗 subdominant.The mean density and biomass of snails in Yangcheng Lake were 220±47 ind./m2 and 2331±469 g/m2,respectively,both of which didn’t display seasonal and yearly variations,but differed significantly spatially.The relatively larger density occurred in CEES and EB and the least in WB;the highest biomass was found in CEES,and the lowest in EB.The highest abundance of 〖WTBX〗B.aeruginosa〖WTBZ〗 appeared in CEES and the lowest in WB,while EB had the highest abundance of 〖WTBX〗A.longicornis〖WTBZ〗 followed by CEES,and TRIB and the other two basins possessed the extremely low values.The highest density and biomass of snails,specially of 〖WTBX〗B.aeruginosa〖WTBZ〗,in CEES suggested that the enclosure culturing of 〖WTBX〗E.sinensis〖WTBZ〗 couldn’t led to the decline of density and biomass of the snail communities,and this fact would be explained by throwin of snails(mainly 〖WTBX〗B.aeruginosa〖WTBZ〗)towards the culturing enclosures of 〖WTBX〗E.sinensis〖WTBZ〗.The stepwise regression analysis showed that among physical and chemical environmental factors only water depth could be used to explain the spatial variations of snail density and biomass,and the canonical correspondence analysis(CCA) indicated that 〖WTBX〗B.aeruginosa〖WTBZ〗 tended to occur at sites with higher concentration of chlorophyll a,while 〖WTBX〗A.longicornis〖WTBZ〗 and 〖WTBX〗Parafossarulus striatulus〖WTBZ〗 at sites with larger transparency

Limnological region in middle and lower reaches of the Yangtze River is China’s most intensive and eutrophic freshwater lakes.As one of the main factors of primary productivity,the nitrogen and phosphorus increase will significantly affect the primary productivity in lakes.The vertically generalized production model(VGPM)and Talling model comprehensively consider the affecting factors of water temperature,photosynthetically active radiation at the water surface,chlorophylla concentration,euphotic depth to phytoplankton primary production.Using VGPM and Talling model,we studied phytoplanktkon primary production of lakes located in the middle and lower reaches of the Yangtze River.As the results show,the mean primary productivity was 0139~0381 gC/(m2·d)during 1987~1991,0128~0504 gC/(m2·d) during 2001 to 2005.The mean fixed carbon amount via the phytoplankton photosynthesis was 3 32125 tC/d during 1987 to 1991,and 3 76502 tC/d during 2001 to 2005 by VGPM,increasd 1336%.But it increased from 2 39964 tC/d to 3 27242 tC/d by Talling model,increased 3637%. 

Zhelin reservoir has large area and storage,but its catchment area is relatively small.Main constraining factor is deficient water resource.Research of the wet and dry climate conditions and its trend of upstream area in the last 50 years is very important to make effectiveness and scientific investment plan for Zhelin reservoir.Different time scales of standardized precipitation index(SPI index)were calculated by using daytoday precipitation,temperature and other observations data of three conventional meteorological stations in upstream area of Zhelin reservoir from 1958 to 2007.Using SPI index,dry and wet conditions of river basin were studied.Based on FAO PenmanMonteith method,evapotranspiration was calculated.Margin of annual precipitation and evapotranspiration was on behalf of approximate maximum depth of runoff.Linear trend fitting,moving average,and other analytical methods were used to analyze droughts and floods,evapotranspiration,maximum depth of runoff time distribution,seasonal changes,trends and so on.The results show that on the upstream area of the Zhelin reservoir basin,annual precipitation had a significant downward trend,but evapotranspiration had a upward trend since 1998,which led to maximum depth of runoff obvious declining and reservoir water resource being shortage.In the last 50 years,the precipitation concentration showed an upward trend in the river basin.The contribution to the total precipitation of heavy rainfall was increased.The risk of droughts and floods was increased.Droughts and floods appeared alternately in the last 50 years.The frequence of droughts was higher than floods.

Ecosystem management can help achieve diverse objectives in natural resources management.The paper believes that although Dongting Lake features a superior wetland ecosystem and advanced socioeconomic development in the region,it is also confronted with the challenge of balancing environmental protection and economic development.In terms of wetland ecosystem management,Dongting Lake faces many threats,including frequent occurrence of natural disasters,unwise use of resources,severe agricultural and industrial pollutions,poor ability in nature conservation,and seasonal water scarcity.All these problems,both old and new, reduce the ecosystem functions of the lakes,leading to decreased biodiversity,reduced capability of flood control,exacerbated floods and water logging,increased underground water level,and lowlying polders.The impact of these unsustainable human activities will persist,posing a major risk to the natural growth of aquaculture industry and to the safety of natural resources,and severely constraining the socioeconomic development in the lake area.For this reason,it is recommended that the lake area should,on the basis of following ecosystem approach,strengthen innovation and practice on ecosystem management system,and speed up the process of formulating and implementation regulations on wetland conservation.Great efforts should also be made to develop midandlongterm overall plan in Dongting Lake,and engage different stakeholders in further carrying out the projects such as returning cropland to lake,wise use of wetland resources,development of wetlandbased and floodadaptive industries,and environmental protection of the lake area,with an ultimate goal of achieving ‘harmonious development between human beings and nature’ in and around Dongting Lake

The spectral absorption coefficients of particulate matter in Lake Donghu,Lake Liangzihu and Lake Honghu were studied based on the data collected on 27 September and 1~3 October 2007.The absorption spectra of total particulates were similar to those of phytoplankton，suggesting that phytoplankton accounted for a large contribution of particulate matter.Significant higher absorption coefficients were recorded in Lake Donghu and Lake Liangzihu than in Lake Honghu，indicating that the underwater climate was better in Lake Honghu than in Lake Donghu and Lake Liangzihu.Larger spatial differences of particulate matter absorption coefficients were found in Lake Liangzihu and in Lake Honghu than in Lake Donghu.The absorption spectra of nonalgal particles of the three lakes showed the same pattern,following an exponential increase toward short wavelengths with an average slope of 1231±032 μm-1,1196±084 μm-1,1198±168 μm-1 over the 400~700 nm interval in Lake Donghu,Liangzihu and Honghu,respectively.Significant positive relationships were found between phytoplankton absorption coefficients 〖WTBX〗a〖WTBZ〗ph(440),〖WTBX〗a〖WTBZ〗ph(675) and phytoplankton pigment concentration (〖WTBX〗p〖WTBZ〗<0005),suggesting that phytoplankton absorption coefficients could be calculated from phytoplankton pigment concentration.There were significant correlations between total particulate matter,nonalgal particulate absorption coefficients and the concentrations of total suspended solids,organic suspended solids,inorganic suspended solids.A significant linear relationship was found between phytoplankton absorption coefficients and organic suspended solids concentration,suggesting phytoplankton dominated in organic suspended solids

The study of temporal trend of precipitation in river basins has been paid more and more attention.In this paper,based on the precipitation data from 13 weather stations during 1960~2003 in Hanjiang River basin,the annual and seasonal precipitation and continued rainy days were analyzed.Results showed that average rainy days in spring accounted for 25%~31% of annual rainy days,precipitation accounted for 21%~31% of annual rainfall.In summer,average rainy days accounted for 13%~18% and precipitation accounted for 50%.There were 22%~31% rainy days and 21%~29% precipitation amounts in autumn.In winter,rainfall only accounted for 6% of annual rainfall, average precipitation in rain days was 28 mm.Besides,continued rainy days distribution model in different station and seasons were studied.Chisquare goodness of fit tests was performed on precipitation data to compare the fit of the models.The results indicated that Polya probability distribution was statistically feasible.At the α=01 significance level,95% of stations in Hanjiang River basin passed the verification.But 4 stations in spring could not pass the verification.Polya probability distribution model could be used to estimate probability of continued rainy days in watershed science.It will provide guidelines for flood prevention and disaster alleviation,also will provide scientific references for the middle route of South to North Water Transfer Project in China

It is important to further explore the nature features before the SouthNorth Water Transfer Project and hydraulic control measures on ecology protection after the project. This paper used IHA method to analyze the discharge data in Daduhe River transfer area before project,then took the monthly low flows as the characteristic flows,which was important to maintain the basic ecological river system,and used Tennant method to assess them.With taking the characteristic flow as a reference,the paper concerned the advantage to the ecosystem of the monthly average flows postproject in the stations reaches.It also calculated indirectly the monthly low flows downstream the dams and discussed the advantage to the ecosystem of monthly average flows in the dams reaches.The results show that with the restoration of flow along the way,the discharge in Chuosijia station and Zumuzu station had been restored so that the monthly mean discharge was better to the river ecology after the fist stage water transfer project.While,the monthly mean discharge downstream the dams were too low to support the normal river ecology.The river ecological conditions in the downstream of the Zhu’anda dam and the Huona dam were“very poor”under the situation of the monthly mean discharge in June after the project

With large scale of human activities for water resources utilization,the water cycle process was changed,in turn the water ecological space was evolved reversely,which emerged in more and more ecological and environmental problems.Then studying on ecological water requirement has been a focus at home and abroad.Compared with foreign countries,there are more complex ecological effects of the water cycle,more serious ecological environment problems,and more severe and urgent ecological water requirement in China because of a large differences in the natural areas.Based on the review of the development and the main research results for ecological water requirement,the typical area,valley and the research object are comprehensively pointed,the concept and connotation are scientifically defined,the theories are systematically introduced,the calculation and its practical application are also summarized.These results point that ecological water requirement is still in its infancy,which is the main reason leading to inconsistent and unreliable method of ecological water requirement,and causing difficult to achieve the expected results in water resources planning allocation and manage practice.Therefore,the direction of ecological water requirement in future should focus on basin ecological water requirement based on basin ecosystem integrity and stability.The key scientific issues mainly include the impact mechanism of climate change and human activities on ecological water requirement and scaling law analysis of ecological water requirement,etc.The basic research of ecological water requirement should be further strengthened for building the scientifically theoretical methods and technology system for China,which can provide a solid support for accurate calculation of ecological water requirement

As river degradation becoming the primary problem faced by the river ecosystem of countries all over the world,more attention has been paid to river health assessment.Determination of reference condition and identification of spatial and temporal features are described as the critical components of river health.The spatial and temporal features aids to the selection of indicator of river health assessment,while establishment of reference condition contributes to the determination of criterion.Considering river hierarchy theory,river continuum concept and a fourdimensional matrix,main characteristics of river system and features of its spatial and temporal scale were analyzed.The paper profiled spatial scale of river health assessment from dot (section and site),line (stream and reach),and surface (river basin and river system) grades,and demonstrated temporal scale from short (temporal dot),middle (temporal segment) and long (temporal section) hierarchies.Reference baselines of river health assessment,including minimally disturbed conditions (MDC),historical condition (HC),least disturbed condition (LDC) and best attainable condition (BAC) were defined.Determination procedure and application scope of reference baseline calculating methods using reference site,historical data,expert opinion or simulation models were discussed.Finally,some suggestions to improve the effectiveness of river health assessment were presented

Hydrophobic organic contaminant (HOCs) is one of the persistent organic pollutants (POPs) with high 〖WTBX〗Kow〖WTBZ〗 values in environment.Sorption/desorption plays an important role in HOCs transportation in the aquatic system.Recently，coal was investigated as a significant sorbent in soils/sediments for nonlinear sorption.In the present review,the mechanism of sorption/desorption of coal and carbonaceous sediments was discussed,considering different sorbents and sorbates,pH,salinity and ion strength,etc.Due to the different physiochemical properties,such as TOC content,material compositions and structures,coal and carbonaceous materials exhibit remarkably sorption characteristics,such as nonlinear sorption,hysteresis of sorptiondesorption.Up to now，study on the mechanism of HOCs sorption/desorption of coal and carbonaceous materials in soils/sediments is still scarce,particularly from the aspect of molecule,the function of other factors in the sorption process of coal and the risk assessment on the degradation of HOCs by coal.