The purpose of this paper is to overcome the problem that the uniform classification model cannot be used to improve the accuracy of land use classification effectively, and to provide a method with high precision and efficiency to extract qualitative and quantitative information of land use/cover. In this paper, two extraction methods, i.e., the hierarchical information extraction method and the method based on knowledge and rule, are combined. The hierarchical information extraction method can create a cleaner extracting environment when extracting specific types of land use/cover. The method based on knowledge and rule can give full play to the role of priori knowledge and experience, and reference diverse assistant information comprehensively. The purpose of combining the two methods is to further improve the classification accuracy. Taking the metropolitan area of Nanjing as an example, a set of land use information hierarchical extraction process is designed and put into effect. In the extraction process, TM image spectrum information and the temporal and spatial characteristics of land use in study area are fully considered. Using different ways and data such as water extraction index model, Ratio Resident-area Index (RRI), NDVI, DEM data and the urban built-up area boundary, we extracted eight types of land use/cover, i.e., water, urban build-up area, rural build-up area, mining land, bare land, woodland, farmland, and urban green land. Specially, we constructed a build-up and quarry discrimination index (BQDI) to efficiently distinguish build-up area from mining/bare land, and make full use of elevation and slope information to extract woodland from vegetation coverage area. In addition, the urban build-up area boundary plays an important role in distinguishing urban build-up area and rural build-up area, farmland and urban green land, mining land and bare land. The results showed that the overall accuracy (OA) reached 88.67%, and the Kappa index reached 0.85 when extracting the land use/cover information of 2012 in study area. Besides, the overall accuracy on other years' information extraction were all higher than 87%, and the Kappa index were all more than 0.84. We concluded that the hierarchical land use information extraction method based on knowledge and rule possesses high precision and wide applicability. The method has a good reference value to land use/cover extraction practice in other regions. Further research should be undertaken to increase the degree of automation in information extraction process, the efficiency and accuracy of extraction in the future.

Based on the remotely sensed data of land use/land cover in Jiangsu Province in 1985, 1995, 2005 and 2008, a combined spatial analysis using GIS, Ucinet social network analysis software and atlas analysis were conducted to comprehensively and quantitatively study the spatial-temporal variations of land use change in Jiangsu Province during 1985 to 2008, including the variations of land use change rate, land use transformation direction and land use intensity. Results showed that: 1) The integrated dynamic degree of land use dynamics during 1985-1995, 1995-2005, 2005-2008 was 12.95, 17.17 and 15.03, respectively, suggesting that the impact of human activities on land use change followed a rule of inverted U-shape curve starting from slight to intense impacts and then to slowing-down impacts. This phenomenon seems to be closely related with regional socioeconomic transformation process, yet other case studies and more rigorous mechanism studies are needed. 2) Since 1985, the land use interchange flows between cultivated land, built-up land and water area have been dominant in the land use dynamics of Jiangsu Province. They reflected the main manifestations of the impacts by human activities on land use dynamics, accounting for more than 80% of all land use change flows. In addition, the flow of cultivated land into built-up land ranked as the top land use change type, mainly distributed in the metropolitan areas of Suzhou, Wuxi, Changzhou, and Nanjing as well as in the developed county-level cities such as Kunshan and Jiangyin, and also in part of the North Jiangsu of including Suqian, Huaian and Xuzhou. These conclusions are in line with existing findings of previous case studies, indicating that the comparative economic advantages between various land use types have driven those land use changes along with regional development process. 3) As land use intensity is an indicator closely related with capital input and economic output per unit land, its spatial-temporal variations gave other hints of the dynamics of human activities. Since 1985, the pursuit of direct economic output prompted the increasing of built-up land and the decreasing of cultivated land, leading to the ascending growth of overall land use intensity degree in Jiangsu. This impact of human activities on land use change was most obvious in South Jiangsu all the time while it was ever-increasing in North Jiangsu. Our findings provided novel insights into land resource sustainability in Jiangsu Province, suggesting new possibilities to better manage land resources in accordance with regional socioeconomic development stage.

The enhancement of ability and intensity of social and economic activities has made particular ecosystem damages extend to regional eco-environmental problems. Facing a series of eco-environmental problems, social development under rapid urbanization is no longer economic growth, but the coordinated development of population, economy and eco-environment. Especially when urban agglomeration becomes the new units for global competition and international division of labor, evaluating and identifying its developmental pattern between eco-environment and urbanization has practical significance for achieving sustainable development. The Yangtze River Delta Urban Agglomeration (YRDUA) has paid a great price for its burgeoning urbanization and industrialization, which gradually became one of the new ecologically vulnerable zones in China. With reference to the Technical Criterion for Eco-environmental Status Evaluation (HJ/T192-2006) published by the Ministry of Environmental Protection of China in 2006, we selected Biologic Abundance Index (BAI), Vegetation Cover Index (VCI), Water-net Density Index (WDI), Land Deterioration Index (LDI) and Pollution Load Index (PLI) as the Ecological Index (EI) to reflect the comprehensive eco-environmental quality (EEQ).The basic characteristics and spatiotemporal pattern of EEQ in the YRDUA during the Eleventh Five-Year Plan Period (2005-2010) was analyzed. Furthermore, we took the 25 cities in the YRDUA as analytic units and discussed its status and spatial differentiation of developmental patterns between eco-environment and urbanization under the perspective of "population-economy". The results showed that: (1) the averaged EI in the YRDUA was 56.0 in 2005 and 57.3 in 2010, which was higher than the national average and were both belonged to the "moderately high" level. Concerning to the spatial distribution, the EEQ demonstrated pronounced variability, with the Shanghai-Suzhou-Wuxi-Changzhou-Nanjing belt as a demarcation belt. The EEQ of Lishui in Zhejiang Province ranked the best and Shanghai the last in terms of administrative unit. (2) During the Eleventh Five-Year Plan Period, the EEQ in the YRDUA kept steady growth. The proportion of significantly better areas was up to 10%, mainly distributing in Zhejiang Province and Shanghai-Nanjing belt. It was policy-induced emission reduction that gave rise to the overall eco-environmental improvement, followed by an increase in the volume of water resources and land degradation. On the contrary, the biological abundance reduction as well as reduced vegetation cover caused by land use change resulted in some regions' deterioration of the EEQ. (3) Most cities remained sustainable in terms of the developmental pattern between eco-environment and urbanization, but a direct consequence of industrial structure and economic base led to disparity in the developmental trajectories. Some cities including Shanghai presented economy-advancing coordination while other cities such as Suzhou and Hangzhou were in ecology-advancing coordination. On the other hand, 5 cities in northern Jiangsu showed an ecological vulnerability pattern, which indicated economy and urbanization had a strong coercing effect on the eco-environment.

Due to strong human interference, the implementation of land-use master planning (LUMP) will produce a profound impact on the structure and functions of ecosystems. Therefore, in order to avoid the potential threat from the initial decision-making phase, it is essential to introduce and establish an assessment mechanism in the planning to analyze the negative ecological effects on ecosystems and its acceptability. The combination of LUMP and ecological risk is a new research field that present interdisciplinary and challenging characteristics. In view of current development, although its importance has been recognized, quantitative analysis has not yet been conducted, and the depth of the research is actually inadequate. In China, LUMP is characterized by hierarchy. According to the range of administrative districts and decision-making effect, it can be classified into five levels, i.e., national-level, provincial-level, municipal-level, county-level, and town-level. The property, scope, and degree of ecological impact will vary with LUMP at the different levels. Therefore, a corresponding ERA system with planning levels needs to be established to improve the pertinence and operability of evaluation. The aim of this paper is to discuss how to carry out relative risk model (RRM) for the municipal LUMP. By applying the RRM, a relationship of relative risks can be obtained, which is applicable to comparing ecological risk degree among the assessment subdivisions in the study area. With an example, LUMP of Leshan City, which has been completed by the local land department, is investigated for its ecological risk. The city is divided into three units in terms of the topography (southwest mountains area, central valley plain area and northeast hilly area), eight types of habitats (cultivated land, garden land, forested land, grassland, other agricultural land, construction land, water area and natural reserved area), five risk sources (crop planting, livestock breeding, industrial production, transportation construction and population load) and three assessment endpoints (biological species, ecological system and landscape pattern). The evaluation results showed that the general ecological risk of Leshan City is on a downward trend in the planning period. The spatial difference in ecological risk is significant while the basic pattern of ecological risk has not changed after the planning implementation. In some places, the ecological environment will fluctuate and even deteriorate. There are three major sources of ecological risk, including crop planting, transportation construction and population load. The ecological pressure on the forested land and grassland is the most acute among all habitat types. And the damage of structure and function of ecological system is the major forms of risk effect. According to the research achievements, the emphasis of ecological risk prevention and control can be identified, and it can provide references to the practice. In addition, this method is helpful to regional ecological risk analysis. It should be noted that the assessment model presented still has a rise space for promotion, mainly through refining quantitative methods to improve the accuracy. And more research needs to be explored further in the follow-up work to other scale LUMP.

Aquatic ecoregion is considered a geographic unit for conservation, treatment and ecological restoration at basin scales. According to the method of material valuation and the geographic information system technique, assessment of ecosystem services based on aquatic ecoregion is important for optimization of land use, ecological environmental protection, treatment and restoration. The area surrounding the Chaohu Lake was selected as the study area in this paper. Twelve types of ecosystem services were quantified in this study, which are water regulation, water purification, soil protection, and habitat maintenance in terrestrial ecosystems and water supply, aquatic product production, water storage, water purification, climate regulation, carbon sequestration and oxygen release, waterlogging regulation, and biodiversity protection in water ecosystems, respectively. The results indicated that: (1) There were significant spatial differences of ecosystem services in the study area, which was higher in the south and northeast of study area, and lower in the northwest and southeast. Ecosystem services per unit area were higher in the west and lower in the east. (2) The areas where ecosystem service functions were high, may not be high in per unit area of them. Regulating services in per unit area in terrestrial ecosystems was higher in the southwest and northwest of study area, and lower in the northeast and southeast. Supporting services in per unit area in terrestrial ecosystems was higher in the south and north of study area, and lower in the east and west. Moreover, supporting services in per unit area in water ecosystems was higher in the west and southeast of the study area, and lower in the north. Regulating services in per unit area in water ecosystems was higher in the southwest and northwest of the study area, and lower in the south and north. (3) Management and restoration of ecosystem services should consider not only the total ecological service functions, but also the per unit area of them. According to the actual situation, the area where ecosystem service functions are higher, should actively pay equal attention to its ecosystem service function under the condition of the protection and management. On the other hand, its ecosystem service functions should be restored on the basis of the protection where ecosystem service functions are lower. The results have great significance to the development of regional industry and arrangement of land use among the agriculture, forestry, fishery and other industries. In order to coordinate and cooperate with each industry to form the development of the integrated system, it can be achieved the protection, optimization and rational utilization of natural resources and renewable natural resources.

Assessment of ecosystem services are more and more applied in natural resource management. In this paper, we applied the FoPIA approch to build different land use/land cover scenarios in Poyang Lake wetlands by 2020. Then, we used the scenario parameters and land use/land cover indexes as input into the Integrated Valuation of Ecosystem Services and Tradeoffs model (InVEST). InVEST has been used to assess a typical village's habitat quality of migratory birds which is the biodiversity index of species in Poyang Lake wetlands. Results showed that: under the conversation scenario, the scale of habitat quality of migratory birds will be increased and the threat of human activities will be decreased obviously, influenced by ecological engineering, all these will making the average of habitat quality of the migratory birds in the typical village of Poyang Lake wetlands reach 0.89, showing an increase of 27.0%. Under the economic developing scenarios, human activities will be expanded and some of the superior quality habitat will be occupied by agriculture lands, therefore, the average habitat quality will decrease to 0.57, showing a decline of 14.0%. Under the nature developing scenarios, human activities will not change so much, and the average habitat quality is 0.66, showing an increase of 1.5%.

The Laohegou Stream is the third-grade tributary of Yangtze River in Sichuan Province. By the field sampling and data analysis from 14 sites in Laohegou Stream in each season in 2012, a total of 11 species were recorded, representing 4 families and 4 orders. Among which, 7 species belong to Cypriniformes, accounting for 63.64% of the total. Some species of them, such as Rhynchocypris oxycephalus, Triplophysa bleekeri, Homatula variegate, and Euchiloglanis kishinouyei, were common species. They completed their life history in a relatively short river reach. While Misgurnus anguillicaudatus, Pseudobagrus truncates, and Pseudobagrus tenuifurcatus were occasional species, and only appeared in the wet seasons of the Laohegou Stream. Our result showed that species richness and individual abundance of fish increased gradually along the longitudinal gradient from the headwater to the stream outlet. The highest species richness and individual abundance were observed in summer and winter, respectively. And the lowest values of them were ascertained in spring and summer. Result from One way ANOVA indicated that species richness and individual abundances showed significant difference between the 14 sites (P<0.01), while they showed no significant differences between seasons (P>0.05). Cluster analysis and multidimensional scaling (MDS) were performed to examine the spatial distribution pattern of fish. It suggested that the fish assemblage were separated into three groups-upper, middle and lower reaches on a Bray-Curtis similarity value of 40.77%. Results from the analysis of similarities (ANOSIM) suggested that the fish assemblage were significant difference among the upper, middle and lower reach of the Laohegou Stream (Global R=0.722; P<0.01). Through analysis of similarity percentages of species contributions (SIMPER), we determined the specific species such as Zacco platypus, Belligobio nummifer, Schizothorax prenanti, R.oxycephalus, T.bleekeri, H.variegata and E.kishinouyei which result in significantly different among the three groups. Results from the canonical correspondence analysis (CCA) indicated that elevation, substrate, flow velocity, dissolved oxygen, conductivity, total dissolved solid, water temperature, pH and water depth were impact factors resulting in difference in the spatial and temporal pattern of fish assemblages in the Laohegou Stream.

In this research we use water footprint theory and calculation method to systematically study the dynamic change and evaluate the benefits of agricultural water footprint in Sichuan Province from 2003 to 2011, using the method of grey correlation to analysis the driving force factors. The results indicated that: (1) both the total and the average agricultural water footprint of Sichuan Province showed an increasing trend. Agriculture water footprint of Chengdu City, Nanchong City and DaZhou City is larger, which is 8.244×10⁹ m³, 4.556×10⁹ m³ and 4.102×10⁹ m³ in 2011. Per capita agricultural water footprint between different cities is not big, Chengdu City and Panzhihua City are higher. (2) The benefits of agricultural water resources show: the net trade of agricultural water footprint are positive in various cities in Sichuan Province, which is a typical water output region. In 2006, 2009, 2010 and 2011, agricultural water resources scarcity degree is higher, the highest shortage of water resources occurred in Chengdu City, which is more than 200% per year from 2005 to 2010. (3) The driving factors of agricultural water resources show that: multi-cropping index and population is the key factor to agricultural water footprint changes, the correlation coefficients are 0.643 3 and 0.632 5. We suggest to improve the utilization efficiency of water resources, appropriately control the scale of water production, rational allocation of water resources, and realize water space of coordination.

To analyze the impacts of air temperature on annual runoff in the headstream of Yangtze River and explain the physical mechanism behind the glacier melt from Qinghai-Tibetan Plateau, the Generalized Additive Model of Location, Scale and Shape (GAMLSS) is employed to detect the non-stationarity of the annual runoff series (1960-2012) and to quantify the relationships of both the mean and variance of the annual runoff variable to physical factors such as precipitation and air temperature. In the GAMLSS model, the impact of air temperature can be represented in two different ways, one is to directly use the annual average temperature as a predictor and the other way is to use the index of accumulated temperature deficit (ATD) as a predictor, so two kinds of regression models are established in this paper under four different distribution assumptions for annual runoff variable. By comparing the efficiencies of the two kinds of GAMLSS models with different combinations of predictors using a variety of criteria such as the generalized Akaike information criterion, both normal QQ and worm plots of the residuals, Filliben correlation coefficient and kernel density estimation, we investigated the impacts of air temperature on annual runoff in the upper Yangtze River. We found that annual runoff series from the Batang station generally had an unstable trend, with a slight decline during the period 1960-1988 followed by a rise for over twenty years later, while annual precipitation and air temperature values showed continuous, steady and slow increasing trends. The fact that there existed a decline in annual runoff for nearly 30 years can be partly explained by the phenomenon called refreezing of meltwater of glaciers. The fitted model with ATD as a predictor under the lognormal distribution assumption for annual runoff performed better than the direct use of air temperature as the predictor in estimating annual runoff values. The ATD series, as an indirect reflection of heat energy deficit, showed roughly the same change trend as annual runoff series. All the above findings indicate that annual runoff series of the Batang station over the period 1960-2012 might be more strongly influenced by the proposed ATD index rather than directly by the air temperature, suggesting that the ATD index could more effectively explain the physical mechanism of glacial runoff generation that is a significant component of the total runoff in cold regions and hence better describe the temporal characteristics of annual runoff in the upper Yangtze river. In summary, our study may be helpful in predicting annual runoff and understanding the mechanism of runoff generation under the plateau climate.

Understanding the distributions of nutrients in different medium can help to fully grasp the current situation of river environments. To investigate the distribution characteristics, pollution degree and relationships of nutrients in the main stream of the Xitiaoxi River, water, suspended sediment and surface sediment samples were recently taken from 11 sites along this River. These data can help us to recognize the nutritional levels of diverse sections in the mainstream. The results showed that, the concentrations of TN and TP in the waters were higher in the wet season than in the dry season from upper reaches to lower reaches of the Xitiaoxi River. The contents of TP showed they were worse than Grade Ⅲ level of National Environment Quality Standard for Surface Water in half of total sites. In contrast, the concentrations of TN showed that they were worse than Grade V of the surface-water standard (GB3838-2002). NH₃-N in the wet and dry seasons all reached level Ⅱ and Ⅲ, respectively, in the middle and lower reaches. The overall NH₃-N pollution showed the pattern of lower reaches> middle reaches> upper reaches. Therefore, compared to phosphorus pollution, nitrogen pollution of water was more serious in the Xitiaoxi River. The contents of TN in suspended matter basically increased with an order of the upper reaches, lower reaches, and middle reaches from high to low, and the contents of TP showed an order of the upper reaches, middle reaches, and lower reaches. The contents of organic matter of upper reaches were higher than those of lower reaches and middle reaches. The maximum of both TN and organic matter appeared in XTX1 of upper reaches, which indicated a high organic matter and nitrogen values in forested lands. Inorganic phosphorus took up a higher proportion than organic phosphorus in sediment TP, which indicated that inorganic phosphorus was the main form of phosphorus forms. Although inorganic nitrogen accounted for a small proportion of TN, they can indicate a good water quality. Results from statistical correlation analyses showed that TN content in suspended sediment was obviously positively correlated with OM (r =0.974, p<0.01). TN of all sites in waters were correlated with the nutrients in suspended sediment. No significant relationship was found between nutrient in sediment and TN, TP in water, which indicated that sediment could not reflect the status of water quality in basin well. Therefore, control and treatment of water pollution in Xitiaoxi River should focus on abatement of suspended matter in water.

Shallow lakes are important freshwater resources which have the functions of flood control, transportation, agriculture, aquaculture, tourism, drinking and ecological protection. The environmental quality of shallow lakes is highly relevant to human health and sustainable development of society and economy. Rapid urbanization and economic development have resulted, progressively, in deteriorating freshwater conditions. In Jiangsu Province, there are about 200 freshwater lakes with a total surface area of 6 853 km² that account for 6% of the total land area of this province. These lakes are all shallow lakes and are subject to disturbances by natural and human activities. In the past decades, human activities have caused serious environmental problems, such as eutrophication, heavy metal pollutions, organic pollutions and habitat degradation. In order to characterize heavy metals pollution in surface sediments of shallow lakes in Jiangsu Province, the contents of eight heavy metals (Mn, Zn, Cr, Ni, Cu, As, Cd and Pb) in surface sediments from eight shallow lakes were measured by inductively coupled plasma-atomic emission spectrometer (ICP-AES) and mass spectrometer (ICP-MS), and the geo-accumulation index and the Hkanson potential ecological risk index were applied for assessing the status of sediment heavy metal enrichment and the extent of potential ecological risk. The average content of heavy metals in surface sediments of these lakes were in the range of 634-1 031, 66-138, 76.0-97.5, 39.2-56.3, 25.2-50.1, 9.9-27.1, 0.15-2.98, and 24.6-51.6 mg/kg for Mn, Zn, Cr, Ni, Cu, As, Cd, and Pb, respectively. The results from correlation analysis showed that Cr and Ni have the similar origin with Mn, Zn, Cu, Pb, respectively. The results of geo-accumulation index indicated that Cd was the main pollutant in surface sediments of these lakes, Zn, Cu, As, Pb and Ni caused light pollution in some lakes, and Mn and Cr were at a clean level. For the different lakes examined in the present study, the general indices of potential ecological risk followed the order of Changdang Lake> Shijiu Lake> Baima Lake> Gehu Lake> Gaoyou Lake> Hongze Lake> Chenghu Lake> Luoma Lake. Changdang Lake reached the serious ecological risk level, and heavy ecological risk existed in Shijiu Lake. Baima Lake and Gehu Lake had moderate ecological risks, while Luoma Lake, Hongze Lake, Gaoyou Lake and Chenghu Lake imposed low ecological risks.

Hanjiang River is the largest tributary of the Yangtze River in the middle basin, and water pollution has become increasingly serious and the ranges of polluted areas have expanded in recent years. With the development of economy and society and the completion of the first phase of the middle route of the south-to-north water diversion project in 2014, the water consumption in the river basin increases rapidly and the water has been transferred. The pressure of water resources and water ecological environment of Hanjiang basin becomes increasingly apparent, and the management of the basin is facing greater challenges nowadays. Based on the monthly water quality monitoring data in three key monitoring control stations (i.e., Xiangyang, Xiantao, Hankou Stations) from 1998 to 2011, the Seasonal Kendall Test was used to detect long-term trends of pollution indicators in the middle and lower reaches of the main stream of Hanjiang River. In terms of salt permanganate index and ammonia nitrogen, it showed a more statistically significant decreasing trend in the three key monitoring control stations. In terms of total phosphorus, it showed a more statistically significant decreasing trend in Xiantao and Hankou stations, but a non-statistically significant decreasing trend in Xiangyang station. In terms of BOD, it also showed a non-statistically significant decreasing trend in the three key monitoring control stations. In terms of dissolved oygen, it showed a more statistically significant decreasing trend in Xiangyang station but a more statistically significant increasing trend in Xiantao station and a non-statistically significant increasing trend in Hankou station. Ammonia nitrogen showed the largest decrease. The accuracy of the model has been verified by the superposition index method. In terms of temporal trends, water pollution is changing from heave pollution to moderate pollution gradually, and In terms of spatial distribution, the water quality in the middle reaches of Hanjiang River is better than that of the downstream. It shows that the water pollution of the middle and lower reaches of Hanjiang river main stream is under control. The Hurst exponent method was applied to analyze the sustainability of trends of pollution indicators. The sustainability trends are positive for all the pollution indicators. Therefore, the trend of water quality change in the middle and lower reaches of Hanjiang River will be consistent with the 14 years before. The water quality can be improved significantly with water environmental protection and management by relevant departments.The research provides technical support for water environment protection and planning.

Stable isotope analysis can be used to investigate water sources of plants because of no isotopic fractionation during water uptake by terrestrial plants. Ecosystems in the karst region of southwest China are very fragile due to the thin soil layer and intensive infiltration capacity of rock fracture, which result in a very limited amount of water storage for plant uptake. Water retention in the soil zone and shallow fractured rock zone (subcutaneous) is a key factor for plant growth. However, the source of water for plant growth in karst region remains unclear. Distinction of water sources taken by karst plants is a challenging task for botanists and hydrologists, and has important implications for ecosystem management. In this study, we selected 5 dominant plant species grown in various micro-habitats in the Wangjiazhai catchment, a typical karst desertification area in Guizhou Province. The spatial heterogeneity of plant water sources at niche scale and the response of the heterogeneity to different karst rocky desertification degree were studied. Proportions of water sources for plant uptake were determined by the δD and δ¹⁸O values of plant stem water, and the water taken from different soil layers and the subcutaneous zone. The following conclusions were drawn from the analysis: (1) The δD and δ¹⁸O values of soil water were significantly different among various micro-habitats, stony surface had the most positive δD and δ¹⁸O values, stony crevice had the most negative δD and δ¹⁸O values, the others had the medium δD and δ¹⁸O values. The δD and δ¹⁸O values of soil water were significantly different in soil profile and the δD and δ¹⁸O values of soil water in the 0-10 cm layer were more positive than those in the 10-30 cm layer. (2) The plant species absorbed water from both soil layers and subcutaneous zone and these plant species extracted more water from soil layers than subcutaneous zone in rainy seasons in general. The proportion of plants water use from the subcutaneous zone decreased with increasing degree of karst rocky desertification. Pyracantha fortuneana, Rhamnus davurica and Viburnum utile in slight and non karst desertification grade extracted water from both soil layers and subcutaneous zone, while these plants only used water form soil layers in medium and severe grade, and Platycarya longipes and Carpinus pubescens in non karst desertification grade extracted water from both soil layers and subcutaneous zone, while these plants only used water form soil layers in slight grade, which is mainly due to various vegetation types, disturbance regimes, soil conditions and crack growth degree of rocks in different grades plots.

Litter decomposition in forested rivers is an important component of material cycle and energy flow in forest ecosystems, and it is a key process of forest nutrient output and information exchange across ecosystems as well. However, little is known on the process of litter decomposition in alpine forest rivers during different freeze-thaw periods in winter. The present study was conducted to investigate litter mass loss during different freeze-thaw periods of winter in an alpine forest river. Using the litterbag method, a field experiment was conducted to investigate foliar litter mass losses of four regional typical plants willow (Salix paraplesia), azalea (Rhododendron lapponicum), cypress (Sabina saltuaria), and larch (Larix mastersiana) in pre-freezing period, freezing period, and thawing period during temperature fluctuation in winter in an alpine forest river in the upper reaches of the Minjiang River. The results suggested that foliar litter of willow, azalea, cypress, and larch lost 45.5%, 18.9%, 26.4% and 23.8% of the initial dry mass after the incubation of a whole winter (162 days), respectively. Compared with the other freeze-thaw periods, foliar litter mass losses were the highest in pre-freezing period except for that of willow, which was the highest in thawing period. Foliar litter mass losses of willow, cypress, and larch were significantly and positively correlated to river average temperature, positive accumulated temperature, flow velocity, and nitrate concentration regardless of sampling periods. The mass losses of these three foliar litter types were significantly and negatively correlated to water pH in river. Except for a significant correlation between azalea foliar litter mass loss and river water HCO₃^- concentration, no significant relation was observed between azalea foliar litter mass loss and water temperature or other water characteristics. These results indicated that water characteristics of the alpine forest river significantly influenced foliar litter decomposition and its related processes of material cycles, but the magnitude of this influence was controlled by foliar litter features. Under a scenario of global warming, the freezing and thawing patterns in alpine forests could be influenced significantly, subsequently having influences on the water physicochemical characteristics and litter decomposition in forested rivers. A warmer temperature in winter may generate a higher river flow velocity, which would promote litter decomposition. Furthermore, warming-induced microbial activities could also accelerate litter decomposition because of constant moisture in aquatic ecosystems. As a result, litter decomposition in alpine forest rivers would be meaningful for nutrient cycling and energy flow relative to that in forest floors under a scenario of global changes.

The Mid-Route South-North Water Transfer Project taks water from the Danjiangkou Reservoir to overcome the water shortage in the North China. Once the Reservoir is impounded, the normal water level of the reservoir would rise from the elevation of 157 m to 170 m, and the areas of water-level-fluctuating zone could increase from 232.0 km² (between the elevation of 150-160 m) to 285.7 km² (160-172 m). The soils of newly submerged area with different land uses may be a potential source to release nitrogen and phosphorus into the overlying water, causing a huge threat to the water quality of the reservoir. Based on the survey of the existing (between the elevation of 149 m-160 m) and newly increased (160 m-172 m) water-level-fluctuating zone in Dongkuwan and Caijiadu from northern bank of the Danjiangkou reservoir, several surface soil samples were collected from different land uses and the distribution characteristics of nitrogen, phosphorus under different land uses and elevations were analyzed. The results indicated that the surface soils of beach land and hybrid zone had a higher content of organic matter, with the values of 43.9 g/kg^-1 and 49.8 g/kg^-1, respectively, indicating organic matter can easily accumulate in the disturbance place and biodiversity area. The average contents of total phosphorus (TP) and nitorgen (TN) of the existing (between the elevation of 149 m-160 m) and newly increased (160 m-172 m) showed no significant differences (p>0.05). In both water-level-fluctuating zones, the soil of orchard had the maximum content and water-soluble phosphorus (WSP). The newly increased (160 m-172 m) water-level-fluctuating zone had a higher drop-out rate of phosphorus (0.564%) than the existing (between the elevation of 149 m-160 m) ones, indicating that it is necessary to take measures to prevent the risk of phosphorus loss in the newly increased water-level-fluctuating zone. The contents of TN and organic matter (OM) in the soils of the water-level-fluctuating zone had a significant correlation (p<0.01). The TN content in the soil varied from 0.044% to 0.167%, and the farmland and orchard, strongly effected by artificial cultivation, had a relatively high TN contents. Some measures like returning farmland to forests or restoring the vegetation communities are needed to implemented to effectively reduce the loss of nitrogen and phosphorus in the soil of water-level-fluctuating zone.

Based on 555 topsoil samples (0-20 cm) collected from the Renshou county of Sichuan Province in 2012, spatial variability of topsoil pH at the county scale in the hilly area of Mid-Sichuan Basin was analyzed using geo-statistics, while variance analysis and regression analysis were employed to quantify the extent of impact of the main factors on soil pH variability. Results show that soil pH values in the study area range from 4.02 to 8.14, with an average of 6.80. Overall, 41.08% and 32.07% of soil samples are neutral and alkaline soils, respectively. Coefficient of variation is 14.48%, indicateing a moderate spatial variability. Geostatistical analysis showed that the best theoretical model is the spherical model with a nugget/sill ratio of 0.302, suggesting that soil pH has a moderate spatial dependence, and structural factors play a dominant role while random factors also have an impact on spatial variability of soil pH in the study area. The range is 52.7 km, suggesting soil pH has a large range of spatial autocorrelation. Variance analysis shows that land use type, soil type and parent material have significant impacts on soil pH. Land use type and soil parent materials are able to explain 4.8% and 76.2% of the spatial variability of soil pH, respectively. The explanatory power of soil type is related with soil classification. Soils in lower soil categories of the soil classification are more capable of explaining the spatial variability of soil pH. Soil group and soil subgroup are able to independently explain 41.3% and 57.3% of soil pH variability respectively, while soil genus independently explain 83.7% because soil genus is classified based on both soil-forming process and characteristics of parent materials which have a great effect on soil pH. Therefore, it is advisable to use soil genus as main influencing factors in predicting and assessing spatial distribution of soil pH value at the county scale in the hilly area of Mid-Sichuan Basin. This result provides useful information for management and construction of ecological environment for the study area.

In order to reveal the Yangtze research's hotspot and development, we chose Web of Science as the data source, using the bibliometric method and Thomson Data Analyzer (TDA), and conducted a quantitative analysis on the number of published papers, countries, institutions, authors, journals, subjects and keywords. The result shows that (1) the Yangtze research could be divided into three stages, i.e., the initial development period, the exploration period and the rapid development period. (2) China published the most papers of Yangtze research, the main foreign countries and institutions come from the United States, Japan, and Australia. (3) Chinese Academy of Science is the major institution for Yangtze research. (4) Domestic and international concerns rest ongeology, environmental science, water resource and meteorology.

With rapid development of regional socio-economy, the accumulation and pollution of heavy metals in urban soils has become increasingly prominent. The study of distribution and sources of soil heavy metals can provide a theoretical basis to protect the ecological environment and construct suitable living environment. Soil heavy metals concentrations along the typical urban-rural gradient (City Center, Suburbs and Outer Suburbs) in Shanghai were analyzed to investigate the effect of urbanization and industrialization on soil environment quality. Spatial variation structure and distributions of soil heavy metals (Cu, Pb and Zn) in the top soil along the urban-rural gradient were analyzed. Descriptive statistics and geostatistics were used to analyze the spatial variation structure and distributions of the 3 heavy metals (Cu, Pb and Zn) in the top soil along the urban-rural gradient. The results showed that the coefficients of variation (CV) for Pb, Cu and Zn ranged between0.24 and 0.62, which demonstrated a moderate variation. The total content of Pb, Cu and Zn showed normal distributions in the Xuhui District, while showed log-normal distributions in the Minhang District. Zn showed normal distribution, while Pb and Cu showed log-normal distribution in the Fengxian District. From City Center to Outer Suburbs, the obvious variation exited in the spatial distribution of Cu, Pb and Zn. The results of semivariance analysis showed that Pb, Cu and Zn can be fitted with the spherical model, the strong spatial correlation for Cu, Zn and obvious spatial correlation for Pb exited in the Xuhui District as a fully urbanized area. Pb were fit with the linear model, Cu were fit with the Gaussian model and Zn were fitted with the exponential model, the strong spatial correlation for Pb, Cu and Zn exited in the Fengxian District with agriculture lands. Pb, Cu and Zn were fitted with the linear model, especially the pure nugget model, the strong randomness and the weak spatial correlation for Pb, Cu and Zn exited in suburbs, the Minhang District. The non-sampled locations were estimated and the spatial distribution maps of heavy metal content of the topsoil were obtained using the Kriging method. The results indicated that the spatial distribution of Pb, Cu and Zn content in City Center, Suburbs and Outer Suburbs were obviously different. The variation of soil Cu, Pb, and Zn were weakened and the structural factors of the spatial distribution were increased from the city center to the outer suburbs. The main influencing factors were urbanization, industrialization and traffic pollution.

Using the historical documents from 1160 to 1950, the characteristics of floods and droughts in the Poyang Lake basin are studied. Firstly, the flood and drought disasters were classified, according to the description of historical documents. Secondly, by using the method of wavelet analysis, the method of correlative dimension and the method of fractal dimension of time, the fractal dimension of flood and drought disaster of Poyang Lake were studied. Thirdly, Hurst index of decadal floods and droughts was calculated by using the R/S analysis method. Combined with the results of trend analysis and wavelet analysis, the flood and drought of Poyang Lake were predicted and verified by using the SPI index. The conclusions are as follows: 1. the proxy data of the Poyang Lake basin inevitable has some missing data during the long period because of various reasons. In the social unrest periods, the data missing rate maybe even higher. It will have poor reliability for the analysis of the proxy data as a whole because of the missing data. So the proxy data would be smoothed to reduce the uncertainty. Literature proxy data on flood record rate have certain continuity between adjacent periods, analysis through the periodic variations of the smoothed data sequences, with better credibility, to analyze and estimate the change trend of the sequence of the stage, has certain scientific significance. 2. From 1160 to 1940s, the intensity and frequency of flood and drought in the Poyang lake basin and sub-basin showed a trend of fluctuations and had an obvious characteristic of cyclic changes, 3-6 decades and passed 95% reliability analysis. 3. The drought has the period of quasi-3-6 decades, and the flood has the quasi-3-6 decades also. 4. The Hurst indexes of drought ranged from 0.7 to 0.8, while the indexes of flood ranged from 0.8 to 0.9. The flood and drought time series have the nearly linear fractal characteristics. 5. According to the historical data, the frequency of flood and drought are predicted to show a rising trend. The predicted results are matched with the observation facts. It means the R/S analysis method can be used in the prediction of floods and droughts in the Poyang Lake Basin.

Middle and Lower Reaches of the Yangtze River is not only the main agriculture region of China, but also one of the areas with precipitation anomalies and frequent floods. The study of the tendency of extreme precipitations of Middle and Lower Reaches of the Yangtze River can provide a reference for agricultural production and local flood control and disaster mitigation. Daily precipitation data from 84 meteorological stations in the Middle and lower reaches of the Yangtze River during 1961-2012 were used to derive annual maximum series (AM) and peak over threshold series (POT). We used moving average, Mann-Kendall test, linearity trend estimation and other methods to study the changes of extreme precipitation events. The results showed that (1) in the past 52 years, the extreme precipitation in the Middle and lower reaches of the Yangtze River had significantly increased, the extreme precipitation rate was 9.3 mm per 10 years, the extreme precipitation had inter-decadal variation, and since 1990 the extreme precipitation had increased obviously. (2) The maximum perennial average value and standard deviation of the spatial distribution of AM and POT were the highest in Jiangxi Province, the southeastern of Hubei Province and the southern of Anhui Province. The maximum standard deviation of the spatial distribution of AM and POT occurred in the southeastern and northern of Jiangxi Province, the southeastern of Hubei Province and the northwestern of Hunan Province. It is large in the central part and small at the north and west part. The perennial average value and standard deviation AM were larger than POT, and the annual fluctuation was significantly stronger than POT. The annual fluctuation of the extreme precipitation was larger than the annual variation. (3) The annual maximum daily precipitation along the Yangtze River had an increasing trend, and the western region of the Yangtze River's northern showed a decreasing tendency. The extreme precipitation along the Yangtze River, the middle area and the eastern region mainly showed an increasing trend, and the western region showed a decreasing tendency. In the past 52 years, the extreme precipitation of Middle and Lower Reaches of the Yangtze River had an increasing tendency, and the extreme precipitation rate was 0.93 mm/year. The extreme precipitation of Middle and Lower Reaches of the Yangtze River expression annual variation, the trend was low-high-low-high-low-high. The annual maximum daily precipitation of Middle and Lower Reaches of the Yangtze River showed a significant increasing and strengthen tendency. The extreme precipitation of each station also showed an increasing trend, but the variation degree was different. After 21 century the extreme precipitation times of Chuzhou station did not change obviously, but the extreme precipitation strength was increasing, so the precipitation was more concentrated.

Drought occurs when precipitation is significantly lower than normal and it has been one of the most severe disasters all over the world. It can cause huge agricultural and economic loss when lasting for a long time. Hubei Province is located in the middle reaches of Yangtze River basin, which belongs to the temperate continental monsoon climate zone. It plays an important role in agricultural production of China. Recently, more frequent drought has occurred in Hubei Province and caused heavy losses. The basic characteristics of drought and its spatiotemporal patterns in this region need to be understood comprehensively. Quantitative analysis is useful to implement the suitable measures for drought mitigation. Based on standardized precipitation evapotranspiration index (SPEI) at different time scales, the meteorological data of 40 observation stations were used to analyze the characteristics of drought in this region. The objective of this study is to analyze drought in Hubei Province and describe its patterns from various aspects objectively and quantitatively, and to provide basis for moving forward and taking counter measures. The SPEI has been widely used for drought analysis and monitoring because of its robustness in multiple time scales. The role of evapotranspiration is also been included in the calculation of SPEI, which can represent water balance well from point of input and output. The evaluation indicators include drought frequency, drought stations proportion and drought intensity. The results showed that drought was widespread in Hubei Province, since 54% of years during 1961-2012 were identified as large-scale drought. However, the drought was not severe. The average intensity was 0.65. Severe drought only occurred in 2 years over the recent 52 years, while slight and moderate drought years accounted for 85%. Both of drought intensity and drought stations proportion has increased during the last 52 years (the tendency is 0.041/10 a and 3.692/10 a respectively.) Specifically, they decreased before the 1980s and then increased significantly after the 1980s. And it's obvious that 1980s was a period of transition which had lowest drought intensity and drought frequency. The similar results have been found from the viewpoints of the average drought intensity, the drought frequency and the drought area. This is consistent with previous studies in South China. Spatially, the drought frequency was higher in the east and lower in the west, ranging from 16.5% to 18.2%. From interdecadal views, the drought frequencies in the 1970s and the 1980s were the lowest (high-incidence area of drought was small in the 1970s and the 1980s), and increased after the 1980s. After the 2000s, the drought intensity, drought frequency and drought area all increased obviously and tended to continue increasing. And the spatial difference of drought frequency was also increasing. The results are in line with previous studies and records, which also indicated that SPEI was suitable for drought analysis in Hubei Province.

Based on the monthly data of 37 meteorological stations over the Central Yunnan Plateau during 1961-2010, the standardized precipitation evapotranspiration index (SPEI) was used to study the spatiotemporal patterns of droughts. To assess the temporal patterns of droughts as multi-scale events, the SPEI were calculated for seasonal (6 months) and annual droughts (12 months). In this study, the trends of SPEI were detected with linear regression and Mann-Kendall nonparametric test. The morlet wavelet analysis method was used to detect the change interval of annual mean SPEI. The spatial distribution characteristics of SPEI were analyzed via empirical orthogonal function (EOF). The results indicated that: (1) the annual mean SPEI at 37 meteorological stations of the Central Yunnan Plateau was positively correlated with precipitation anomaly percentage and had good sensitivity to the variation of precipitation. Spatial patterns of the SPEI in 2010, 2005 and 1993 over the Central Yunnan Plateau showed good coincidence with the historical drought records; (2) over the Central Yunnan Plateau, annual mean SPEI showed a decreasing trend since the beginning of the 1970s, however an increasing trend was found in the middle of 1990s, and then a continuous decreasing after 2000. The SPEI at 6-month timescale shows a significant decreasing trend in the dry-season (November-April in the following year) in the whole, but there was no significant trend in the rainy season (May-October); (3) the morlet wavelet analysis revealed that the annual mean SPEI fluctuated significantly with the interval of 24 years and 9 years. The Central Yunnan Plateau tends to be dryer after an abrupt changes in annual mean SPEI occur in 1977; (4) from the spatial distribution, four spatial patterns of SPEI variability were objectively defined by the EOF analysis, which were associated with distinct temporal variations and geographical area over the Central Yunnan Plateau. As a result of the influence of large scale climate systems, the annual mean SPEI showed a decreasing trend in the whole research area. Most significant decreasing rate of annual mean SPEI was found in the Southeast parts of the study region. There was no significant trend of annual mean SPEI in the Southwest, whereas the hot-dry valleys along the Jinsha River showed a significant increasing trend of annual mean SPEI during the past five decades.

In recent years, the magnitude of global warming was more serious than before, increasing the occurrence frequency of drought, frost and other natural disasters. In Southwestern China, persistent snow, ice storms and persistent drought events attracted a lot of attentions since 2008. Therefore, it is very important to investigate the variation of extreme temperature events and its mechanisms. By using daily maximum and minimum temperature at 88 meteorological stations in Southwestern China in the period between 1962 and 2012 provided by China Meteorological Administration, temporal and spatial variation of extreme temperature events were investigated using the methods of regression analysis, Mann-Kendall rank correlation and inverse distance weighted interpolation. Eight indices of extreme temperature were studied. The results indicated that extreme temperature indices were obviously different in spatial distribution. The indices of warm days, warm nights, cold nights, and extra-minimum air temperature decreased gradually from southeast to northwest, with changing rates of 13.1-36.3℃,-1-23.5℃,-15-15.2℃ and-30.6-6.7℃, respectively. Nevertheless the index of frost days increased in the same direction with maximum change over the northwest of Sichuan. Both the distributions of cold days index and extra-maximum air temperature are like a saddle, with the highest values over the southwest and northeast. There were few high temperature days over most areas. Obvious gradient of hot day index can only be seen over central Yunnan. The indices of cold day, frost days and cold nights have significantly decreased by the rate of 2.7 d/10 a, 3.5d/10 a and 4.9 d/10 a, respectively. Warm days indices, warm nights indices, extra-minimum air temperature and extra-maximum air temperature have significant increased by the rate of 1 d/10 a, 4.7 d/10 a, 0.4℃/10 a and 0.1℃/10 a, respectively. Only hot days indices did not change significantly. The magnitudes of changes in cold indices are much greater than those in warm indices. The changing ranges of night indices were larger than those of day indices, which indicated that the changes of day and night temperature were asymmetrical. The variation of extreme cold indices showed a downward trend, and that of extreme warm indices showed an upward trend. Their overall performance had a warming trend over Southwestern China. Whereas, the variation range of extreme temperature events was less than other regions of China which reflected the unique feature of climate change over Southwest China.

Using the daily rainfall data of 178 stations from 1961 to 2010 and the DEM data of Yangtze River Basin, the spatial and temporal variation of the frequency of annual average rainstorm days during the last 50 years in the Yangtze River Basin were analyzed with the Mann-Kendall trend test, coefficient of variation analysis and the GIS spatial analysis methods. The results showed that: there is a spatial tendency that the frequency of annual average rainstorm days is declining from East to West in the Yangtze River Basin, and gradually reduced as the altitude increases, showing significantly negative correlations; influenced by the plateau climate on upstream reaches of the Yangtze River Basin, the frequency of average annual rainstorm days is less than one day, and the spatial distribution of annual average rainstorm days in the upper-middle reaches of the Yangtze River Basin is mainly affected by the humid subtropical climate; with increasing latitude, the starting time of rainstorms is delayed, but the end time moves forward, and the duration of the rainstorm have a decreasing trend; coefficient of variation of annual rainstorm days and annual average rainstorm days showed an exponential relationship, their correlation coefficient was 0.97. In a large number of annual average rainstorm days (small) local coefficient of variation is small (large); the variation of annual average rainstorm days in the central of the middle-lower reaches of the Yangtze River Basin and the Sichuan Basin and its surroundings present a decreasing trend, other areas showed an increasing trend for varying degrees; while the river systems of Poyang Lake, Sichuan Province (the cities of Ya'an, Emeishan and Wanyuan), Hunan Province (Anhua County and Nanyue District) and Hubei Province (Honghu City and Yingshan County) have many rainstorm days with less coefficient of variation, and just because of this, it faces a lot of pressure in order to cope with floods and geological disasters; and the research could help the government to acknowledge the mechanism of flood disasters in the Yangtze River Basin, and to improve the ability of prediction and precaution.