There is increasing attention focused on the variations in global vegetation condition due to its importance in the global carbon cycle. The vegetation variability arises from many causes. It is well known that climate drives ecosystems on both local and global scales. How and to what extent the vegetation responds to the large-scale climate change is a challenging subject in global change study. In the northern mid- to high-latitudes there experienced dramatic temperature variations, as well as the significant changes in vegetation conditions during the last about two decades. However, both temperature and vegetation variations are not uniform in geographical distribution. In the present study, the authors analyze the spatial features in Pathfinder AVHRR-NDVI/temperature relationship over northern hemisphere in spring for the period from 1982 to 2000. A singular value decomposition analysis is utilized to the covariance matrix of NDVI and temperature. Most of the squared covariance is captured by the first several paired-modes. The first seven modes account for 91.6%. This implies that the temperature is a very important factor influencing vegetation activity. The NDVI changes in response to temperature fluctuations on the interannual time scale show well-defined large-scale and consistent patterns. The first paired-modes, which explains 42.64% of the squared-covariance, indicate the strongest coupling between vegetation and temperature appears in western Siberia. The large-scale atmospheric system, Eurasian pattern (EU), plays a dominant role for that. The relationship between NDVI/temperature and nine large-scale atmospheric circulation systems is analyzed. Results show that much of the NDVI/temperature covariance can be attributed to the fluctuations in these circulation indices. Averaging over the mid- to high-latitude northern hemisphere, 55.6% of the satellite-sensed NDVI variance is explained. The nine climate indices can account for a large portion of the long-term trends in NDVI too, particularly in the northwestern North America, southeastern North America, most of Europe, Siberia, and East Asia. This implies that the regional response of vegetation to climate fluctuations under future climate change scenarios would differ from region to region. Some areas related to the important circulation systems would experience higher sensitivity and predominant changes than other regions.
Based on the idea of Top-down and Bottom-up advocated by Huang Bingwei, five integrated divisions in China, including the physio-geographical division, the ecological division, the potential agro-productivity division, the economic division, and the response to global warming of China, are integrated to divide the terrestrial system of China into nine regions at the first level. Then by evaluating the Pressure, State and Response on 46 components for 344 prefectures in China with the PSR Models, the criteria in seven grades for terrestrial system status in every prefecture are established, and terrestrial system status for nine regions are assessed. The results show: (1) The regional differences in landforms and climate are the dominant priority to the regional terrestrial system status. (2) The socio-economic development dominated by human dimension is the secondary priority to the regional terrestrial system status. (3) For terrestrial system status in nine regions, North China, Southeast China and South China are at better level; Northeast China is at middle level; the Southwest China and Shaanxi-Inner Mongolia-Gansu-Shaanxi are at poor level; Northwest China and Qinghai-Xizang are at the worst level.
In order to study the change of land use/land cover, the technologies of remote sensing and GIS were used to analyze the spatial pattern change of land use in recent ten years, China. Firstly, the landscape types of land use in China were divided into six main types and 26 sub-types. Then the land use classification information was extracted from the raster database of 1:100000 scales resource and environmental database. Secondly, the mathematical methodology dealing with landscape-ecology was explored and developed for study on spatial pattern and spatial-temporal changes of land use, including the indexes of the landscape diversity, the landscape dominant, the landscape homogeneity and the landscape broken. According to these landscape indexes of spatial patterns, a clear picture of the interference degree caused by human activities can be made. Thirdly, the change of the land use gravity center and the transition matrix of landscape types of land use in ten years were calculated and the spatial pattern changes of land use were analyzed.
According to the grain yield response to fertilizers, China's fertilizer application rate can be classified into 3 typical regions: (1) the maximum fertilizer input region including 11 Eastern provinces (ER region); (2) the middle fertilizer input region covering mainly 10 Middle provinces (including Xinjiang and Gansu) (MR region); and (3) the low fertilizer input region consisting of 9 Western provinces (WR region). The average fertilizer application rate per ha cultivated land (sowing area) in 674 counties of ER region was 329 kg/ha, the average rate in the 973 counties of MR region was 231 kg/ha and that in the 709 counties of WR region was 231 kg/ha (Fig.1). The maximum application rate in some counties of China was found to be as high as 2,241 kg/ha which was nearly 10 folds of the average of whole China, i.e., 238 kg/ha. According to the response of grain yield to fertilizers, there were 11.9% excessive-fertilized counties which should reduce their fertilizer application rate and 14.6% counties which were not necessary to increase fertilizer application rate in China.
According to the total amount and statues of chemical fertilizer consumption, and grain yields during the last 10 years (1990-1998) in each county of China, regional differences in grain productivity and grain productivity increased by additional application of fertilizers were analyzed and compared. Results of the study are concluded as follows: Grain productivity and grain yield increased by additional application of fertilizers in most of the counties varied from 3500 kg/hm2 to 5250 kg/hm2 and from 300 kg/hm2 to 600 kg/hm2, respectively. The index of grain yields increased (IGYI) by additional application of per kilogram of fertilizers varied from 5 kg grain/ kg fertilizer to 10 kg grain/ kg fertilizer. The grain yield and grain productivity were found to be 5372 kg/hm2 and 7462 kg/hm2 in Eastern Region with high input of fertilizers, to be 4940 kg/hm2 and 7216 kg/hm2 in the Central Region with middle input of fertilizers, and to be 3844 kg/hm2 and 5470 kg/hm2 in the Western Region with low input of fertilizers. It was indicated that potential of grain productivity increase per sowing area was 754 kg/hm2 in the Central Region that was lower than that in the Western Region (948 kg/hm2) and higher than that in the Eastern Region (714 kg/hm2). The IGYI for different regions were found to decrease as the following order: Western Region (9.41 kg grain /kg fertilizer) > Central Region (7.17 kg grain /kg fertilizer) > Eastern Region (-11.1 kg grain /kg fertilizer). It is concluded that the Eastern Region had the highest grain productivity, but had lowest potential for yield increase when more fertilizer is used because less response of grain yield was found to the additional application of fertilizer. However, the response of grain yields in the Western and Central Regions were higher to the additional application of fertilizer Therefore, more fertilizer should be used in the Western and Central Regions to improve China's grain production.
This paper describes valley bottom troughs of the Changjiang River and infers the geomorphological development of troughs. Based on the morphology of the troughs, the following conclusions are drawn. (1) The deep troughs on the Three Gorges valley bottom are formed by river downcutting along the structurally zones on the background of regional tectonic uplift. The data of 14C dating indicate that the downcutting of the troughs occurred at about 40-30 ka BP. (2) When river downcutting occurred in the river bed of Changjiang, the jets current with a large number of pebbles, ground and eroded the valley bottom, resulting in trough formation and deepening. Meanwhile, water currents with gravels and pebbles eroded the bank and the left wall of No.76 trough as well as the right wall of No.77 trough by striking, scouring, horizontal and vertical grinding. The left wall of No.77 trough was developed after trough deepening, when the pressure-released fracture formed on trough bank and hence induced collapse of the wall under the water. (3) The trend of the troughs is controlled by longitudinal structural fissures. The deepest points of the troughs are normally located at the intersection of the longitudinal fissures with the transverse ones. The depth of the trough is mainly determined by the intensity of the water current and the consistency of bedrock against erosion, of which the trough is composed, and is not controlled by the altitude of the sea level as the base level.
The authors put forward six principles for selection of pillar industries in Three Gorges Area: ① good ecological benefit; ② marketable product and market rapidly expanding ability; ③ strong driving and affiliating ability; ④ good economic benefit; ⑤ technical progress and able to adopt new technological knowledge; ⑥ propitious to the labor employment and establish indices, including three hiberarchys,six series and 17 items.The weight of every item is evaluated by AHP:ecological index is 0.28; market index is 0.22; economical benefit is 0.16;technological innovation index is 0.14; labor employment index is 0.12; industrial correlative domino effect index is 0.08. By carefully and deliberately weighing under these indices,the authors think to choose five pillar industries to foster as keystones and analysis their development.
Based on methodology of geo-information sciences, using remote sensing and map data, four maps of oasis distribution covering 1960, 1978, 1990 and 2000 at the northern foot of the Tianshan Mountains are compiled. From 1949 to 1967 the expansion of oasis area is very fast, especially in farmland area where the oasis area was about 0.4 ×104 km2 before 1960 and 1.543 ×104 km2 in 1978. From 1967 to 2000, the dominated urbanization resulted in diminution of farmland area. The urban and construction area was 0.042 ×104 km2 in 1978 and 0.152 ×104 km2 in 2000. This development was mainly because of rapid population growth and economic development. In 1949, population at the northern foot of the Tianshan Mountains was only 39.11 ×104, GDP (Gross Domestic Product) was RMB 11,637.56 ×104 yuan. In 2000, population increased to 479.43 ×104, which was 12.26 times that of 1949, GDP amounted to RMB 6,365,873 ×104 yuan, which was 547 times that of 1949. But the large-scale exploitation to natural resources with population growth and economic development leads to a series of serious eco-environmental problems, for example, about 1/3 of farmland is suffering from soil salinization. Rational utilization of resources and protection of eco-environment will be important approaches.
Based on the land use survey map and data in 1984, 1992, 1996 and 1999, and assisted by spatial analysis techniques of GIS and statistical analysis methods, the spatial-temporal process and differentiation of rural residential land use change were analyzed in Fengtai district, Beijing city. Using the data of rural residential land use and population by village in 1999, a correlative model between rural residential land use and population was set up, and the usefulness and errors of the model were analyzed in 1992. Some results are obtained. (1) The total area of rural residential land-use increased with the elapse of time, but its speed was slower and slower. The increased area was 949.8 hm2, with 63.32 hm2 of annual average and 2.56% of annual average increased rate from 1984 to 1999. The annual increased area and rate were respectively 103.39 hm2 and 4.31% from 1984 to 1992. Those were 20.2 hm2 and 0.69% from 1992 to 1996, and 13.94 hm2 and 0.47% from 1996 to 1999. (2) During 1984 to 1999, the spatial-temporal feature of rural residential land-use change in the district was very remarkable. According to the increased proportions of rural residential land-use in total land area of different townships, the difference between the highest and the lowest was 9%. By the annual average increased rate of rural residential land-use in 1984-1992, 1992-1996 and 1996-1999, there were different increased courses in various subareas away from center city, with "mid-high-mid" in the inner areas of the Third Ring Road, "high-low-mid" in the areas between the Third and Fourth Ring Roads, "high-low-minus" in the subarea outside the Fourth Ring Road and "high-low-low" in the western areas of the Yongding river. (3) Due to the influence of population and policy, per capita living space was close to 203 m2 and population density was adjacent to 50 persons a hectare from 1984 to 1999. And in the coming 5-10 years, 120 m2 will be regarded as the target to regulate the former and 83 persons a hectare will be the one to the latter. (4) The formula of the simulated correlative model between the rural residential land use and population is Sv = 11.324e0.0006Pv. The result of its test and error analysis shows that the model could be applied to predicting rural residential land use change of suburban villages in Beijing city.
Species in genera Abies, Picea and Larix constitute dominant components of cold-temperate coniferous forests in China. In the present study, a number of geobotanical data on these three genera were collected by literature review to explore the distribution of these genera and their interrelations. Using GIS technique and based on the data collected, we established a spatial-explicitly species distribution database for each mesh with a resolution of 1o latitude by 1o longitude for each genus in entire China. The results suggested that: (1) west Sichuan and north Yunnan were modern distribution center common to these three genera; and (2) distribution altitudes of species decreased with an increase of latitude while along a longitudinal direction the distribution elevation appeared a maximum at a longitudinal range of 95o-105o mainly due to existence of the Qinghai-Tibet Plateau although such a trend was frequently impacted by a heterogeneous environment.
The degree of spatial variability of the soil physical properties and the ability of environmental attributes to predict that variability were studied in Da Nangou catchment (3.5 km2) on the Loess Plateau, China. The soil physical properties including soil texture (sand, silt, clay), bulk density, saturated soil moisture content, aggregate stability, soil cohesion, stable infiltration rate were measured at 111 plots across the catchment. It is found that the spatial variation is small for soil texture, bulk density and saturated soil moisture content, moderate for aggregate stability and cohesion, and great for stable infiltration. The spatial distribution of the soil physical properties is due to the joint-influence of land use and topography, and the dominant factors differ for different soil physical properties. There is significant difference in the soil physical properties between different land use types as determined by the correlation analysis. The sand content shows the lowest value while the silt content exhibits the highest values on the woodland, and the silt content is lower for the fallow land than the other land use types. The bulk density exhibits the greatest values for the woodland while it is the lowest for the cropland. For the saturated soil moisture content, it is the greatest for the shrub land while it is the lowest for the woodland. The woodland also is the strongest in the aggregate stability, while the cropland is the weakest. The soil cohesion shows higher values for the shrub land, woodland, wasteland and the fallow land, but it displays a lower value for the cropland. The shrub land is the greatest in the stable infiltration rate, while the intercropping land is the lowest. Based on the correlation analysis, it is indicated that a significant correlation exists between the soil physical properties and the terrain indices. The sand content is lower and the silt content is higher on the concave slope than the other surface types, however, the straight slope shows an opposite picture.
In this paper the measured ecological water flow of the lower Yellow River during 1958-2000 was analyzed and the concept of ecological water requirement was discussed. Based on the unique characteristics of the Yellow River and previous research on its ecological water requirement, the present paper recommends that the water requirement for transport in the flood season and base ecological flow in non-flood season should be both included in the ecological water requirement. The water requirement for transport is 80 ×108~120 ×108 m3 per year if the bankfull discharge carries the largest sediment and contaminant load over a long period of time. The base ecological flows in non-flood season at Huayuankou and Lijin stations are 80 ×108~100 ×108 m3 and 50 ×108~60 ×108 m3, respectively. Proper regulation and control of sediment and water discharges, and quasi-market management of water resources of the Yellow River will be helpful to guarantee the above ecological water requirement.
In this paper, the characteristics and tendency of annual runoff changes of Naolihe River are analyzed, which is regarded as a typical marshy river in Sanjiang plain. Moreover, the aid of gray interrelation analysis and the radial basis function network are applied to discuss the reason of runoff decrease and abrupt changes. The annual runoff of two representative stations of Naolihe River presents the reduced tendency from 1964-1989 using Kendall method. According to mutative point analysis, the changes of annual runoff of Baoqing station that lies in the upstream of Naolihe River divide into two periods covering 1964-1973 and 1974-1989. The range of runoff is 3.56 ×108 m3. The changes of annual runoff of Caizuizi station that lies in the backward position of Naolihe River also divide into two periods covering 1964-1975 and 1976-1989. The range of runoff is 6.29 ×108 m3. Precipitation of the drainage area is the best sensitive factor to runoff changes. The concept of entropy is applied to study the nonuniformity on precipitation of distribution. The results show neither apparent spatial difference nor characteristic of temporal runoff change tendency exists in precipitation. Therefore the climate is not a major factor influencing runoff changes. According to nonlinear and uncertain relationship between various kinds of influencing factors and surface runoff, the model of radial basis function network that can reflect their relationship is built to predict the natural runoff of the drainage area, and be compared with actual measured runoff. The results show that natural runoff of Naolihe River decreases 60% from 1976 to 1980 and decreases 30% after 1980. These characteristics and tendency of runoff changes are related with the characteristics of marshy drainage areas and human activities, especially reclamation of wetlands and exhaustion of water resource largely. Human activities are the major driving force of runoff changes. Marshes have had significant influence on water balance of regional hydrologic systems. It is essential to strengthen the control and management of water resources in order to protect marshes when ground feature of a drainage basin and hydrologic cycle have changed clearly. It is beneficial to sustained utilization of water resource.
Through the study of mutual process between groundwater systems and eco-environmental water demand, eco-environmental water demand is brought into groundwater systems model as the important water consumption item. In addition, the unification of groundwater's economic, environmental and ecological functions were taken into account, hence a three-dimensional simulation and optimized management model of groundwater based on eco-environmental water demand at Da'an in Jilin province was established. All water balance components of groundwater systems in 1998 and 1999 were simulated with this model and the best optimal exploitation scheme of groundwater systems in 2000 were determined, so that groundwater resources was efficiently utilized and good economic, ecological and social benefits were gained.
Zhangjiajie was the first National Forest Park in China. It is also a National Key Scenic Zone, a National Geological Park,and a World Natural Heritage site. With the development of Zhangjiajie's tourist industry, the ecological environment quality of scenic zones began to deteriorate yearly. And this attracted the attention of the World Heritage Spot Committee of UNESCO. The main ecological environmental problems in Zhangjiajie core scenic spots are: The water quality in Jinbian Stream has evidently been deteriorated.. Having done some field monitoring and overall analysis of the trend of environment in Zhangjiajie, we found that the influence of accommodting facilities on the environment is greater than that of the other amusement facilities. So the major influential factor of Zhangjiajie tourist ecological environment is the influence of accommodating facilities on environment. The great changes in the variation of the water quality monitoring value in scenic spots have taken place. That means the water body is the most fragile environmental factor in the ecological environment of the scenic spots. Due to the increasing number of tourists year after year, the deteriorative trend of ecological environment has appeared. As we know from the following analysis: (1) The renovation of the scenic spots environment often fail to focus on the accommodating facilities even though they are not located within the scenic spot, yet still in the upstream area. (2) The fragile ecological environment factor---the changeable curvies of water body environment quality are similar with the increasing curves of the accommodated tourists. The former is left far behind the latter. (3) The sympton of the water deterioration can be seen from the fact that blue algae, and green algea, the phosphate has surpassed the standard. They are the causes of the deterioration of the water quality in the scenic spots. (4) The scope of accommodating facilities in the upstream area has surpassed its ecological threshold, and the excessive use of phosphate in detergents has led to the total phosphate's surpassing the standard. (5) Because of the different number of residents and services, different seasons, areas, so different drainage processing methods should be used. A threshold model for the most fragile environment factor is built into this paper. From the calculation we recommend that: On condition of no surpassing the set water standard in Zhangjiajie---the most fragile environment factor, that is the total phosphate content ≤0.02 ---the ecological threshold of the tourist environment in the upstream of scenic spots. The number of tourists be as follows: n Spring 1186 beds, Summer 3057 beds, Autumn 545, Winter 333.. Different types of scenic zones, the fragile ecological environment factors are different from each other. We follow the same process as this paper recommends,we can calculate the threshold of other scenic zones in the country.
