According to the theory of economic growth and economic growth accounting models(Barro,1999),we conduct a research on the general economic growth accounting for Shanghai,and in order to analyze the sustainable development problems such as green economic growth accounting,we make a study of the green GDP economic growth accounting models(Asheim,2000).Some important results concerning the calculation research on the economic growth of Shanghai are obtained.Firstly,before implementing reform and opening policy,the achievement of Shanghai's economic growth was mostly supported by the input of capital,human resources and labors.And wage policy ensured the input of human resources because of planned economy,but it failed to cause technological progress.After the reform and opening,the achievement of Shanghai's economic growth was benefited from the technological progress caused by some reasons such as institutional innovation and so on,but interfered by the revenue policy.Secondly,Shanghai's green NNP value is far lower than the GDP value,and the latter is at least 2 to 4 times of the former.The ratio between Shanghai's GDP value and green NNP value was maintained more than 3 times that in the 1960s, 1970s and 1980s.In recent years,the ratio reduced to a relatively rational level,being around 2 times between Shanghai's GDP value and green NNP value.This shows that people have awared to pay more attention to the environmental problems and resource wasting problems,and have taken actions to protect environment and reduce resource wasting.Thirdly,at present,we believe that,because of the accounting results of Shanghai's green NNP,green GDP should not be used as a unique index of measuring economic development,but it can be used as an index of measuring the effect on environment and the wasting of resource by economic development as well as a supplement for the GDP index.
The rise of information economy has restructured the competitive advantage of cities in many ways in which cities rise and fall in the global economy.Although the bubble of New(Digital) Economy has collapsed,Internet continues to be a driving force in many places.In these local economies,the leading infrastructure is not highways,ports,rail-ways,or airports,but fiber optic glass network connected around the world.With rapid advances in Internet technology,the spatial framework of telecommunication infrastructure has also been developed rapidly China during the last decade.However,little advances in academic research on Internet,especially the relationships between cities and Internet,are still neither achieving the attention it deserves,nor delivering the quality of empirical research it demands.This paper aims to fill the gap.Firstly,it presents a literature review of communication networks and urban system and recent efforts to measure their structure and performance.Secondly,this paper applies network analysis methods to evaluate Internet connectivity,focusing on the spatial structure and city accessibility of five major Internet backbones in China.The overall Internet infrastructure within China is illustrated in light of the calibration of basic graph-theoretic measures based on gross characteristics.The degree of connectivity of cities included in the networks is measured with the total accessibility matrix(T) and the Shimbel distance matrix(D).The results reveal the construction of new accessibility of cities follows the traditional urban hierarchy.The three national network access points(NAPs) Beijing,Shanghai,and Guangzhou and several regional hub cities are near the top of the accessibility hierarchy.In addition,geographical location of cities plays an important role in the decision-making of infrastructure constructions.Finally,several new themes for further research are highlighted.
This paper presents a study on the fractal urban form of Beijing.We use the city built-up area to define the urban form.It includes all the built-up area of houses,squares and roads,but the roads connecting central cities are not included,nor the water and vegetation.The data is obtained from the Landsat TM images of Beijing.Two TM scenes from 1984 and 1999 are used to cover the city and its adjacent areas.Based on the unsupervised classification using the IMAGINE ERDAS 8.6,the authors conducted an aborative correction on the map so that the classification is accurate enough. ESRI ARC GIS 9.0 is used to get the area data.The authors use the area-radius relationship method in this paper.In this view,the fractal dimension is a way to clarify the convergence and decentralization of urbanized area. The authors found that the city of Beijing bears clear fractal characteristics.The computation shows that there exist double scaling range.The first scaling range is good to reveal the fractal evolution of Beijing.The scaling range is 8km in 1984 while it is 14km in 1999.The extension of the scaling range shows that the fractal characteristic in 1999 is better than that in 1984.The dimension values also indicate the building density of Beijing.In 1984,the density remains almost unchanged in a region of 10 km distance from the center(Tian'an Men).In 1999,the building density increases from the center to a region with a radius of 16.5 km.Both of the building densities decrease outside the corresponding ranges of 1984 and 1999.The fractal model from the area-radius relationship method in this paper has important theoretical significance,which needs further studies. The fractal computation in this paper has important practical significance. The scaling range of a city is a special variable that carries individual characteristics.It is also a comparable variable among cities.Based on this,the authors identified a new city definition using the scaling range.The new definition can avoid the subjective and incomparable factors of the ordinary definition method.The scaling range also has important theoretical significance.
A survey was conducted among 997 city-and-towns selected from 127 counties or county-level cities in Henan province in 2004.Data collected include 4 attributes for each city-and-town,and 3 attributes for about 900 traffic lines and 12 attributes for 127 county-level units.The different attribute values of each city-and-town were converted into the unified index named city-and-town growth equivalent for the sake of simplicity.In the same way,the different length numbers of traffic lines and other indexes in a city-and-town were converted into the linkage intension index,and the development level of its matrix.And here,the other indexes includes passenger traffic,freight traffic,passenger-kilometers,freight ton-kilometers, business volume of telecommunications,number of local telephone subscribers at year-end,number of mobile telephones subscribers,capacity of long-distance call exchanges,number of subscribers of internet service.The paper separately discusses the centralized degree of city-and-town from the following three angles such as the growth of node,and the linkage of traffic network and traffic flows and volume of telecommunications and the level of regional development,and then classifies the study units in the spatial distribution by the corresponding scores.By employing GIS software,this paper divides the spatial structure based on the county unit data,and finds the following results:(1) the core region,including 13 county-level units such as Zhengzhou city,Gongyi city,Xinzheng city etc.;(2) the secondary core region,including 12 county-level units such as Dengfeng city,Zhongmou county,Xinxiang county etc.;(3) the latency core region,including 18 county-level units such as Kaifeng county,Qixian,county,Tongxu county etc.;and(4) the periphery region,including 14 county-level units mainly located to the south of Luoyang city,the south of Pingdingshan city and the north of Xinxiang city.Per capita GDP of the core and secondary core regions,is 2.04 times of the average value in Henan province,but population accounts for 12.22% of the provincial total population,and the GDP occupies 25.93%.In addition to the further development of city-and-town concentrated area in the Central Plains by means of perfecting the city-and-town systems,strengthening the linkages among cities and towns and improving their economic capacities synchronously,more attention should be paid to the improvement of the development level of less developed areas in the future.
Along with the socio-economic development,the various contacts between cities and regions are becoming more and more close and complicated.Although the research on regional characteristic and difference was dominant in geography thoroughly,traditional positive research on economic location and contacts was weak in quantitative methods,one of the main reasons was the shortage of statistic data.By use of the gravity model,we calculated the economic contacts intensity between cities in Henan province and intensity between this province and the other core metropolises all over the country,and with reference to the data of highway and railway passenger traffic,we found the strongly linear correlation between economic contacts intensity and passenger traffic.So we can use the percentage of economic contacts intensity of each city to total region to indicate the economic contacts direction and economic location quantitatively.The directions and intensities of urban economic contacts in Henan province show that the formation of Zhongyuan urban agglomeration including Zhengzhou,Kaifeng,Luoyang,Xinxiang,Jiaozuo,Xuchang,Pingdingshan,Luohe and Jiyuan has close internal economic linkages and passenger traffic contacts,and they also show that the contacts and cooperation between Zhongyuan and Jingjinji(Beijing-Tianjin-Hebei),Changjiang delta,Wuhan and Guanzhong urban agglomerations are beneficial to the economic development of Henan Province.
Human activities have been playing a more and more important role in the environmental changes,especially in the city area where the human activities are most frequent.China is right at high tide of urbanization;and people are putting more and more attention to the environmental problems.Theoretical research indicated that,there is an inverted 'U-shaped' model between the economic development and environmental quality,i.e.Environmental Kuznets Curve(EKC).It means that economic growth helps to improve the environmental quality as the economic development reaches a certain level(the turning point).It has its rationality.From the efficiency of resources utilization and the improvement of the technique,economic development indeed helps to improve the environmental quality.So is there such a rule between urbanization and urban climate? How does urbanization influence urban climate?These directly connect the problem of strategic choice of urbanization in the western development. Through analyzing the influence mechanism of urbanization on the urban climate and the trend of the urban climate changes in about 50 years in Northwest China,this paper studies the influence of the urbanization on the urban climate in Northwest China.And then through setting up the relationship models,it further validates that there exists the Kuznets phenomenon between the urbanization and the urban climate to a certain extent. The study shows that the urbanization has had great influence on the urban climate.The results lead to three main conclusions: 1) This region in urban heat island effect,urban dry island effect,urban rain island effect and urban dark island effect exist in the urban climate;2) Environmental Kuznets Curve(EKC) exists to a certain extent,but can't completely explain the relationship between the urbanization and the urban climate;and 3) the environment improvement in Northwest China is temporary and unstable.
The δ13C annual series in different azimuths of two Cryptomeria fortunei Hooibrenk ex Otto et Dietr（for short CF-1 and CF-3,respectively） tree discs collected from west Tianmu Mountain,Zhejiang Province were determined based on cross-dated tree ring age.The analysis of variance shows that the δ13C values in Cryptomeria fortunei tree rings varied along with azimuths significantly.At the same time,we found the differences of the average δ13C values among azimuths were up to 0.56‰（for CF-3）1.34‰（for CF-1） and the inter-annual variations in each azimuth were up to 0.9‰1.63‰（for CF-1） and 0.6‰1.1‰（for CF-3）.The δ13C variability in space was the same as to the inter-annual.This indicates the study on the azimuth variation of δ13C in tree rings has the same significance to that on the inter-annual variation.The statistical analysis proved that correlation coefficients are highly correlated,ranging from 0.4 to 0.87 for CF-1 and from 0.59 to 0.89 for CF-3 at significance level of α = 0.001 among different azimuths,respectively,as well as from 0.48 to 0.89 for the same azimuths between CF-1 and CF-3 tree discs at significance level of α = 0.001.This indicates that local environmental factors resulting in the δ13C values varying along with azimuths significantly were similar for the two tree rings.In our study,we mainly analyzed the causes that resulted in the differences in the δ13C values at the same azimuths for CF-1 and CF-3 as well as between the different azimuths for both CF-1 and CF-3.The differences of the solar radiation on different tilted surfaces and of the radiant condition（such as radiant intensity and efficient sunlight hours） at the different azimuths on crown of a tree were the most important factors leading to the δ13C variations along with azimuths.The site conditions where the trees stand including latitude,longitude and altitude as well as gradient and slope orientation can affect the variations of the sunlight,microenvironment temperature,humidity and soil nutrient along the different radials and thus affect the variations of δ13C values of tree rings along the azimuths.So the site conditions where the trees were collected are important factors leading to the azimuth variations of the δ13C values in tree rings.
The sand dust precipitation was collectied in Harbin city on Mar.20,2002.The paper deals with chemical composition of Harbin dustfall deposits.The result shows that the major elements of SiO2and Al2O3 and Fe2O3,predominate the dustfall Harbin,occupied 77.8% altogether.The contents of the trace elements such as V,Rb,Nb and Ba evidently are higher than those in Lanzhou dustfall,and the elements of Ni,Cu,Pb,Zn,As and Sr are lower than Lanzhou dustfall.The enrichment factor of Ca,Na and Sr is below 1 being deficit elements,and that of Mg,K,Si,Fe,Mn,P,Ti,Co,Ni and V elements is around 1,derived mainly from lithosphere.Part of Cu,Pb,Zn,Cr and Se is derived from other pollution sources.The enrichment factor of As,Cd and Sb is above 10,derived from pollution sources.The elemental compositions of Lanzhou dustfalls are closer to Lanzhou Loess than Harbin dustfalls,judged from discriminant function（DF） and PI.The Si/Al and Si/（Al+Fe） ratios of Harbin dustfalls are greater than the Earth's surface soils of Northwest China,and chemical weathering degrees of Harbin dustfalls are obviously higher than Lanzhou Loess and Lanzhou dustfalls.Based on the analysis of the chemical composition,discriminant function,PI,cosmid ratio of surface soils and chemical weathering index,the results indicate that element compositions of Northwest Loess are similar to Lanzhou dustfall deposits,while they are obviously different from Harbin sanddust.The source areas of Harbin sanddust differ from Northwest Loess and Lanzhou sanddust,and the status of climate and biology and the degree of chemcial weathering are much better than sanddust sources in Northwest.
Pollen assemblage characteristics which have been used to reconstruct paleoenvironment are taken as an important agent based on modern climate conditions for plants growth.It is particularly so in the loess research.Nevertheless,there are still some problems in deducing paleoclimate by the pollen assemblage discovered in paleosols,which were supposed to have developed under relatively warm and wet climate conditions,thus containing more pollens of trees than of herbs,but it is reverse actually.The best way to probe into such a question period is to observe the process of pedogenesis which was presumed to happen in the interglacial period with the similar climate conditions of today.What happened on the soil surface today might be the same as that in the interglacial period.Therefore this research takes air pollen samples in Beijing under different weather conditions of duststorms and non-duststorms in spring to discuss the pollen assemblage characteristics.The results show that both samples derived from duststorms and non-duststorms contain pollens of trees and herbs,in the majority of trees,representing modern sedimentary environment.Samples of duststorms contain more herbs pollens than samples of non-duststorms,which is argued by the authors to be transported from the source and pathway of storms.Further on,based on the analyses of the amount of dustfall annually,this paper concludes that more pollens of herbs have been transported and deposited under duststorm weather conditions than pollens of trees under non-duststorm weather conditions,which possibly is partial reason for the presence of pollens assemblage in paleosols.Though limit to the samples number this paper's view needs more proof,a new thoughtway on pollen research of eolian sediments still has been put forward.
Water scarcity is one of the most challenging issues in natural resources at present and in future,especially in arid and semi-arid regions.In the Yellow River Basin,rapid growths of population,urbanization,and industrialization have caused ever-increasing competition for water.Any kind of changes in water resource caused by global climate change will have significant implications to such a water shortage basin.This study was conducted to evaluate the potential effects of global climate change on the mean natural annual runoff in the Yellow River Basin under different climatic scenarios of HadCM3 GCM based on the evaporation ratio function of the aridity index,which considers both climate and soil surface characteristics.Six sub-basins were divided based on the runoff producing properties.The mean precipitation and evaporation of 1961-1990 of each sub-basin were obtained based on 56 stations within and around the Yellow River Basin.The future changes in climate were the relative changes between baseline(1961-1990) and different periods(2006-2035,2036-2065,2066-2095) generated by GCM model.The delta change method was to get the climate change for each station.Simulations using HadCM3 A2 and B2 scenarios indicated that the changes in annual runoff varied from region to region within the range of-48.0% to more than 203%.In general,the potential changes in annual runoff decreased from east to west.For the Yellow River Basin,the mean annual runoff increased up to 5.0%,11.7%,and 8.1% for the A2 scenario,and the changes were 7.2%,-3.1%,and 2.6% for B2 scenario by the year of 2020,2050 and 2080,respectively.
The decline in sediment transferring function of the lower Yellow River has drawn attention from the scientific community,the government and the public.Hence,finding out the cause for it is an important and urgent issue in harnessing the Yellow River,both in theory and in engineering practice.An index of sediment transferring function(Fs),which is defined as the ratio of sediment output from a given river reach to the sediment input to this river reach,is applied in this study to reveal the temporal variation in sediment transferring function of the lower Yellow River.It is found that in the past 50 years,sediment transferring function index(Fs) of the lower Yellow River showed a decreasing trend.Due to the changing operation mode of the Sanmenxia Reservoir and the varying combinations of runoff and sediment load,the temporal variation of Fs can be divided into 6 stages.During the period from 1986 to 1997,due to the decrease in annual precipitation and increase in water diversion,the incoming flow of the lower Yellow River was significantly less than the average.As a result,channel shrinking occurred,and the index of sediment transferring function decreased to 0.62,the minimum in the hydro-metrical history.To elucidate the formative cause for the decrease in sediment for the sediment transferring function,the temporal variation in Fs has been compared with the temporal variations in a number of drainage basin factors,including drainage basin factors and river channel characteristics.The results show that the decreasing trend of Fs is basically synchronic with the decreasing trends in the area-averaged annual precipitation in the upper and middle drainage basin,the index of reservoir regulation（defined as the percentage of high-water season flow of the annual total） at Lanzhou and Sanmenxia stations,the bankfull cross sectional area of the typical braided reach and the water surface gradient of the Huanyuankou-Gaocun reach at a given discharge.The Fs index increased with the total area of all soil-water conservation measures,the quantity of water diversion and its proportion of the annual flow.Thus,it is demonstrated that the changing drainage basin factors and channel characteristics resulted in the decrease in the sediment transferring function of the lower Yellow River.
The Wudinghe River watershed is located in the transitional zone between the hilly and gully area of the Loess Plateau and the Mu Us desert,and is a principal contributor of sediment to the Yellow River.Both water erosion and wind erosion are responsible for the heavy sediment yield from the watershed.The contribution of wind erosion to the sediment yield of the watershed is estimated using water-sediment relationships based on water and sediment discharge records at hydrological stations in the watershed and a wind erosion climatic factor calculated from meteorological measurements recorded at meteorological stations in and around the watershed.The results reveal that the role of wind erosion in sediment yield was different in areas with different surface materials during the period from 1958 to 1970 when the water-sediment relationships in the watershed had not been noticeably interfered by practices of water and soil conservation.In the areas with loess hills and gullies water erosion was intensive,and a comparatively low proportion of sediment yield was related with wind erosion.The proportion of wind erosion derived sediment yield of a tributary draining the northern margin of the loess hills and gullies which is near the deserts and covered with sporadic patches of sands was also below 10%.In desert,sediment transport by water played a main role in sediment yield,and the sediment yield associated with wind erosion was only about 1/4 of the total for a tributary draining this area.The highest proportion,over 1/3,of sediment yield due to wind erosion occurred in the area where the river flows between sands and loess areas.The coexistence of both intensive wind erosion in the sands and strong water erosion in the loess areas results in the best collaboration of water and wind in eroding and transporting sediment.For the whole Wudinghe watershed,wind erosion increased by about 1/6 of the total sediment yield through transporting sand and dust from deserts to the river and through promoting water erosion.
The Changjiang estuary located in the coastal area of East China is the largest estuary of the country.The offshore area is the main place where sediments spread and pile up in the Changjiang estuary,and is also the remarkable area of land-ocean interaction.This paper takes the offshore area of the Changjiang estuary as a study area,utilizes the abundant in-situ data to study the characteristic of suspended sediment under the different water conditions and calculates the vertical diffusion coefficients. The difference of suspended sediment concentration is very remarkable in this area,the transient suspended sediment concentration is low,ranging from less than 0.1kg/m3 to over 8 kg/m3,the different runoff,tidal current,salinity and topography determine the complexity of the spatio-temporal distribution of the sediment concentration.The study result shows that the main features of the suspended sediment are in an asymmetric distribution which presents high concentration in the west and south and low in the east and north.This pattern of the suspended sediment concentration distribution proves that the suspended sediment spreading course is obviously influenced by the runoff and ocean dynamics,the topography of relative function and restriction in the study area. The difference in longitudinal distribution is very remarkable in the offshore area of the Changjiang estuary,the sediment concentration reduces gradually from the west to the east,and it is obviously higher in the spring tide than in the neap tide.Salinity is greater than the density of the silt-contained water,as the diluted water from the upper reaches float above the high-density salt water,and fine sediment deposits in the mouth of the salt wedging. Generally,the suspended sediment concentration increases gradually from surface to bed,because of asymmetric distribution and fluctuation of tidal current velocity,the vertical instantaneous velocity is always changing.So it is very difficult to divide various kinds of vertical distribution.The vertical diffusion coefficient is relatively huge in the west and middle water area,and is irregularly distributed in the vertical mixing,so the suspended sediment concentrations increase from the surface to the bottom equably in the area.Along with the strengthening of the degree of the vertical mixing,the suspended sediment concentrations also increase remarkably.As a result,two high suspended sediment concentration zones come into being in the south and the north of the offshore area of the Changjiang estuary.
Spatial and temporal variability of soil basic properties in typical areas of southern Jiangsu province is studied.The following conclusions are obtained.（1） Compared to the second soil survey of China（1980）,soil acidification is severe;soil average pH value of the upper layer declines from 7.20 to 6.42,pH value of 36.51% of the samples is less than 6.0,and that of 6.35% is even less than 5.0.Soil organism is in a declining trend,the average content of the upper soil organism declines from 31.4mg/kg to 28.3mg/kg,soil samples with an organism content less than 20g/kg increase from 0.56% to 11.11%.The available phosphorus shows an obvious increasing trend with average value increasing from 6.4mg/kg to 89.1mg/kg,soil samples with the available phosphorus content over than 20mg/kg increase from 0.74% to 56.66%,and coefficient of variation reaches a high value of 164.6%.CEC decreases from 19.3cmol/kg to 17.8cmol/kg.（2） In different function areas,the contents of organism and the clay（<0.01mm%） have no significant variations in all kinds of function areas,pH of else area（mainly vegetable field） is significantly lower than the others,the available phosphorus of else area is higher than the other function area with an extremely significant level,the content of NH4-N of else area is higher than the others with a significant level,and gets an extremely significant level in areas related to chemical factories and aquiculture,CEC of the area of chemical factory is lower than the others with a significant level.（3） In different physiognomic areas,the contents of organism,available phosphorous and NH4-N have no significant variations in all kinds of physiognomic areas,pH of soil upper layer is significant in all kinds of physiognomic area,and pH of lake area in the south is the smallest（5.51）,lower than the low area in the north and the plain area in the middle with an extremely significant level,the lower layer pH of lake area in the south is significantly lower than the other two,CEC of lake area in the south（22.2cmol/kg） is higher than the other two with a significant level,the content of soil clay <0.01mm（%） is significant in different physiognomy,that of lake area in the south is higher both in upper layer and under layer,and higher than low area in the north and the plain area in the middle with an extremely significant level.（4） In different profile layers,soil basic properties vary much,pH-value increases with the increase of depth,and the contents of organism,available phosphorus,NH4-N and CEC decrease with the increase of depth.
With the booming of stockbreeding,the production of poultry manure has been increasing continually,which was 2750 million tons in 2002.The production of poultry manure in Sichuan Province was the highest,and then Henan Province and Shandong Province.The average load of cultivated land for poultry manure was 4.19 t/ha in China.The amount of TN,TP,BOD and COD released from poultry manure to water body were 870,345,6000 and 6740 thousand tons per year,respectively.Large amount of poultry manure has been one of the main pollutants to water,threatening the health of soil and atmosphere.Based on the result of clustering analysis,the environmental risks of poultry manure to Chinese cultivated land were divided into four grades: the pollution risk of Shanghai was the highest;the risk of Henan,Tianjin and Shandong was in the second grade;the risk of Beijing,Jiangsu,Hebei,Anhui and Hunan was in the third grade,and the pollution risk of the cultivated land of the other provinces was relatively low.For solving the pollution problem of poultry manure,management should be reinforced,farming-pasturing combined eco-type stock raising should be developed energetically,and economical and practical synthetic utilization technologies for dealing with poultry manure should be developed and popularized,so as to promote the transformation of paultry manure into resources for land use.
There are many reports about the characteristics of spatial distribution of chemical elements in different soils and the interactions between macrofaunas and litter or soil,especially,about the horizontal distribution.However,researches on the vertical distribution are limited.And there are few researches into the relationships among forest littermacrofaunas-soil.This paper tends to combine them into the whole and studies the nutritional elements through forest litter,macro faunas and soil.The study area is a shady slope on a low hill located in the Zuojia Natural Reserve(126°～126°2′E,44°03′～44°04′N) in Jilin province.The mean altitude is 300m.The region belongs to the temperate continental monsoon climate.The zonal soil is dark brown soil.The vegetation is mainly secondary mixed deciduous broadleaf forests with Quercus mongolica and Tilia mandshurica as the dominant species.Four sampling sites are located on the same slope surface but different habtats,such as the valley,foot hill,the middle section and the peak.Forests litter,macrofaunas and soil samples were sampled in each habitat,every 20 apart along the slope.The contents of nutritional elements N,P,K,Ca,Mg,and Fe of litter-macrofaunas-soil were measured in laboratory.The relation and difference of nutritional elements in litter-macrofaunas-soil and the vertical difference in nutritional elements of the same slope surface were studied.The result indicated that the vertical difference of six elements was not quite remarkable on the hill slope surface.The contents of N,P and Ca in macrofaunas were higher than those of litter and soil,but the contents of K,Mg and Fe in soil were more than those of macrofaunas and litter.The changes of N in litter,macrofaunas and soil are consentaneous,that is the content of N in the middle position of the slope surface was higher than in the valley and the peak.This is consistent with the surface soil organic matter.On the upper part of the slope,the contents of P and K were the maximum.The vertical variational trend of Mg and P was level,but the content of Ca fluctuated within a great range.The linear relation of the element content in litter-macrofaunas-soil was better.The variations of elements in litter and macrofaunas contributed to the variations of elements in soil to a greater extent.The variations of N,P,K,Ca and Fe in litter influenced more on the soil than on the macrofaunas.
Based on researches on soil animals in burned forest areas and contrast sample lands around Tahe County in Heilongjiang Province during different years,we analyze the category and quantity of soil animals in order to take them as a biological indicator to reflect the environmental conditions and the restoration after fire.In October,2003,we chose six burned forest areas in different years from 1987 within the study area and a sample land which wasn't destroyed by fire.Separating soil animals by the methods of picking up,Tullgren and Baerman,we obtained 4 phyla,7 classes and 22 orders in all.In addition,soil animals in burned forest areas differ obviously during different years. (1)The category and quantity of macro-soil faunas prove to be very few,especially Enchytraeidae,which takes up a lower proportion in macro-soil faunas the first one to three years after fire,however,some macro-soil faunas which have strong moving abilities,such as centipedes,spiders etc.,account for higher proportions.Furthermore,the number of Enchytraeidae gradually increases and tends to be stable after burning three to five years. (2)Of all the meso-and micro-soil animals,Protura only appears in burned forest areas after burning 16 years and the contrast sample lands,thus,we can conclude that Protura is a fauna which can indicate stable habitat. (3)After burning,the first species which are able to invade and restore are those macro-soil animals possessing strong moving abilities,and then the meso-and micro-soil animals,which are in the prosperous period six to seven years after fire,when the category and quantity begin to decrease and tend to be stable. (4)The intensity of fire influences the restoration of soil animals community to a certain extent,that is,soil animals restore at a higher speed in the areas which suffered from mild burning,after six to seven years,toth the category and the quantity can even surpass those in regions not affected by fire. (5)However,the speed of restoration is relatively low in the moderately and seriously affected areas,which may take longer than 16 years to restore to a normal level.
Changes in land-use may affect the potential of soils to act as a sink for CH4.Samples of lessive,one of the most important soil types in the Sanjiang Plain（45°01′-48°28′N,130°13′-135°05′E,the largest fresh water wetland area in China）,were incubated to investigate the effect of land-use change on methane oxidation in lessive.Significant differences between CH4 oxidation rates of all topsoils were found under different land-uses.The highest CH4 oxidation rate was found in natural meadow（dominated by Calamagrostis angustifolia） topsoil,but man-made larch（Larix gmelini） woodland,dry land（wheat or soybean）,and paddy field soils reduced CH4 uptake by 64%,98% and 117%,respectively,compared with meadow soil.After the natural meadow was reclaimed,the soil water content（percentage WHC） changed,and the soil organic material decreased.So,the diffusiveness of CH4 and O2 into the soil was reduced and the number and activity of methanotrophic bateria was inhibited.These may be the main reasons for the decrease of methane oxidation in lessives after land-use change.Atmospheric CH4 oxidation activity under all four land uses showed a distinct vertical stratification within the soil profiles.Potential CH4 oxidation rates apparently decreased with the depth in meadow soil and woodland soil, indicating a surface maximum for CH4 oxidation capacity in these soils;the methane uptake rate of the buried organic layer in the dry land soil was 13 times higher than that of the plowed layer.The net productivity of methane was observed in samples of all layers of paddy soil incubated under air,indicating that they had no ability to oxidize atmospheric CH4.Correlation analyses of methane oxidation in lessives and physico-chemical soil parameters yielded significant correlations for the concentrations of organic carbon（r= 0.78, p< 0.01）,available N（r= 0.71,p< 0.01） and total N（r= 0.69,p< 0.01）,but negative relationships between CH4 uptake rates and pH（r= 0.69,p< 0.01） or water content（percentage WHC）（r= 0.60,p< 0.05） were observed.Linear regression analysis revealed that an individual chemical parameter,soil organic carbon,could be singled out as an indicator for methane oxidation capacity in lessives under certain temperature conditions.
Cellular automata(CA) are discrete, dynamical systems that are divided into small cells with each cell taking a certain state.The basic idea of cellular automata or extended cellular automata(cellular models) is to reduce a complex system using complex rules into something simpler.This paper discusses a one-dimensional cellular model for simulating river profile evolution.In the mode,channel is represented by a series of square cells which are linked one by one.The model is started by applying a "package" of water and sediment to the first cell.Erosion takes place as the water moves from each cell to its neighbors.Sediment is routed downstream according to a transport equation with the transport rate dependent on the elevation difference between two adjacent cells.The elevation of each cell will change depending on the difference between sediment input and output of a cell.When the "package" has been routed across the last cell,a new "package" is applied at the first location and the whole process is repeated.Rules used in the model are simple.When these rules are applied at small scales,the resulting profile has large-scale properties.For example,despite of the original form,the stream profile always tends to evolve to an equilibrium profile when keeping the water and sediment entering the first cell constant.It also showed that discharge has much effect on channel evolution.The channel prolongation causes the rise of the riverbed throughout the downstream.This study is a first step towards applying cellular models to complex geographical system modelling.
The Bosten Lake,located in the Yanqi Basin,is the largest freshwater lake in China.It is not only the end of the Kaidu River,but also the headstream of the Peacock River,supplying water to the Tarim River and the Tarim Oil Field Base so far. Studies in the past usually focused on the change of water surface and water quality of the lake,seldom on the landscape pattern of the Yanqi Basin using integrated synthetic methods.The landscape pattern and its dynamics of the Basin directly control the distribution and dynamic changes of substance,energy and species,so study of the landscape pattern and its dynamics is necessary. By overlapping and extracting functions with GIS,two conversional matrixes of landscape in the Yanqi Basin were built.Based on two transitional matrixes of landscape,the landscape pattern and dynamics of the Yanqi Basin were analyzed.The results show that after 40 years land reclamation,the artificial oasis presented a trend of expansion in the Yanqi Basin.It is clearly discernible that farmland expanded to the fringe of the transitional zone between farmland and the natural oasis;the model of transition of farmland is from grassland to halophyte hungriness to xenophiles' hungriness,an indication of the process of reclamation of farmland from easy to difficult,i.e.,the constant shrinkage of the natural oasis and the expansion of the artificial oasis.The development of oasis is associatied with the distribution of water resources,when water resource is short,the process of desertification occurs,contrariwise,the process of salinization occurs.Because of the irrational use of the land and water resources,apparent ecological degeneration occurs in the lake water,peripheries of the lake and the oasis farmland in the Basin.For future sustainable development in the Yanqi Basin,attention should be paid to the ecosystem balance between artificial oasis and natural oasis.The management of the oasis eco-environment depends to a greater extent on the regulation of water resources and the rational use of land.
The term 'ecological diversity' is a combination of richness and evenness of an investigation object,including HLZ ecosystem diversity,ecotope diversity and species diversity.Many ecological diversity indexes concern only one aspect of diversity,and neglect the effect of spatial scale on diversity simulation.Actually,it is a precondition to consider muti-scale diversity simulation and assessment that the effect of spatial scale on different diversity indexes has been compared and analyzed.This paper takes Fukang city in Xinjiang Uygur Autonomous Region as a study area to analyze the effect of spatial scale on ecological simulation by Shannon diversity index,Simpson diversity index,Margalef diversity index,Whittaker diversity index,Turner diversity index,Mladenoff diversity index and Scaling ecological diversity index.The result shows:⑴with spatial resolution getting coarser,change of the ecotope evenness is greater than the ecotope richness;⑵Shannon diversity index and Turner diversity index emphasize more on the ecotope evenness,and the ecotope diversities simulated by these indexes show a general trend on better spatial resolution;Whittaker index and Margalef index simply concern about the proportion between the total number of the ecotope individuals and the ecotope types,and the number of the ecotope types more influence on Margalef index,thus the ecotope diversity simulated by Whittaker index has a better trend;and ⑷Mladenoff index and Scaling ecological diversity index take both of the two aspects of the ecological diversity into account,but the richness has more influence on Mladenoff index thus the diversity simulated by the index has no distinct trend;however,Scaling index also concerns the effect of spatial scale,consequently the ecotope diversity simulated by the index has a better trend than the other diversity indexes.
