Land use and land cover change have been strongly affecting the function and structure of landscape ecosystem. Landscape pattern aims to build some optimized landscape which could make landscape eco-efficiency maximize and stabilize. Therefore, in this paper, the Yancheng coast is chosen as a study area and the technologies of remote sensing (RS) and geographical information system (GIS) are applied. Meanwhile, the valuation of wetlands landscape ecosystem services are used to analyze the landscape pattern. Based on ecological processes and resistance model, some proposals were put forward to optimize the wetlands landscape pattern. The results show: 1) The land use structure in the coastal zone of Yancheng has undergone significant change from 1987 to 2007. It is demonstrated that the percentage of farmland area ascends from 36.72 to 46.17, and the percentage of artificial wetland area ascends from 9.96 to 18.72,while that of natural wetland area declines from 44.4 to 26.01. 2) With more land use activities, the intensity of human disturbance to land increased from 1987 to 2007. A series of landscape ecological problems were caused by the increase of human disturbance to land, such as landscape shape complexity, low landscape ecological connectivity and more serious fragmentation of natural wetlands landscape. As a result of landscape ecological connectivity, function and the ecological process, such as energy flow in a landscape was declined. Ecological process and functions of wetlands in the coastal area were different in spatial distribution in 2007. The total value of ecosystem services is 77.09 billion yuan/a. The rate of contribution to the reed marsh, Saline seepweed marsh and Spartina alterniflora marsh is the highest, accounting for 86.91% of the total value, and they are mainly distributed between Sheyang Estuary and Doulong Port, and secondly distributed to south of Doulong Port, while the mud flat, paddy field and aquiculture pond is lower. 3) Based on an accumulative cost distance model, the calculation of the cost distance, and identification of the sources, the critical ecological positions, corridors, and sources were designed in the study area, and the landscape pattern optimization further discussed, such as protecting of nature resources, constructing the buffer region, rehabilitating suitable vegetation types to improve connectivity of landscape. 4) Optimization of wetlands landscape pattern improved flow and connectivity of landscape. The critical ecological positions for flow and connectivity of landscape close to the bays of the Old Huanghe River estuary and Dafeng Port was most important, and it was the primary object to be optimized. 5) According to the principles of landscape ecology, the key to optimize the landscape pattern is to strengthen protection of nature sources, and maintain high landscape connectivity in Yancheng coastal zone so as to realize the objectives of sustainable development in land-use and environmental protection.
Efficiency of agricultural circular economy in 21 city-regions in Guangdong Province during the year 2004 and 2005 was evaluated using super-efficiency data envelopment analysis(SE-DEA) method. The results indicated average super efficiency values of DEA for 21 city-regions have exceeded 2.0 in two years. Eleven city-regions’efficiency values increased in 2005, which meant that agricultural circular economic development in Guangdong as a whole was good. During the year from 2004 to 2005, average comprehensive efficiency, technical efficiency and size efficiency for 21 city-regions were 0.9670, 0.9748 and 0.9910 respectively. For five non-DEA efficiency city-regions, Shanwei was in the state of technical efficiency but non-size efficiency, with increasing returns to scale. The other five cities such as Huizhou, Qingyuan, Meizhou and Jiangmen were characterized by neither technical efficiency nor size efficiency, and Meizhou yielded the lowest technical efficiency and decreasing returns to scale. Agricultural circular economy efficiency in these non-DEA efficiency city-regions could be improved by appropriate readjustment of ineffective inputs and outputs, that is, to retrench excessive inputs or increase insufficient outputs.
Underlying surface change caused by land use change had important influence on urban rainfall-runoff process. Based on actual measured rainfall-runoff data, the Soil Conservation Service curve number (SCS-CN) model modified according to initial abstraction and runoff was used to preliminary simulate the rainfall event runoff coefficients at 0.5 to 10 year rainfall recurrence interval, and annual runoff coefficients at wet, normal and dry year condition in central Shanghai from 1947 to 2006. The impact factors of land use type, antecedent moisture condition (AMC) and rainfall on the rainfall-runoff relationship were analyzed. The results exhibited that: 1) The CN value changing process could be driven into slowing increased period (1947 to 1984), rapid increased period (1984 to 1993), rapid decreased period (1993 to 2000) and slowing decreased period (2000 to 2006). The major impact factors in the four periods were the change of cultivated land, cultivated land, water area and industrial land, respectively. 2) The rainfall event runoff coefficients of 0.5 to 10 year rainfall recurrence interval rainfall, at AMC Ⅰ,increased relatively from 17.21% to 6.14% from 1947 to 2006. Also the annual runoff coefficients at wet, normal and dry year condition increased relatively by 20.49%, 11.83% and 10.02%, respectively. 3) Land use type, soil infiltration ability and AMC, and rainfall were the two important influencing factors to the rainfall-runoff relationship. The impact of land use change decreased with the increase of rainfall intensity while AMC from Ⅰto Ⅲ, and the impact of land use change increased with the decrease of rainfall intensity while AMC from Ⅲ to Ⅰ. 4) The runoff coefficient increased the with increased CN value at different event rainfall intensities and different annual rainfall conditions. The linear relationship and exponential relationship exist between rainfall event runoff coefficient and CN value, and between annual runoff coefficient and CN value, with R2＞0.999 and R2＞0.987, respectively.
Land use changes influence the distribution and structure of terrestrial ecosystems,and also change their carbon storage.One of the important performances in oasis process of arid area is that the natural vegetation degenerates, and the part of it was transformed into artificial vegetation and human communities. At present, the effect of LUCC on vegetation carbon storage mechanism is also not very clearly. According to the CASA model and by using the Landsat MSS/TM/ETM+ data separately acquired in 1976, 1989, 2000 and 2007, this paper estimates the net primary productivity of the Manas River basin. Furthermore, we used mortality model to estimate vegetation carbon densities. Then, we got different types of vegetation carbon storage. Finally, we analyzed the impact of transformation during different land use/cover classifications on the vegetation carbon storage, in the Manas River basin between 1976 and 2007. Also, we traced the land conversions in the period between 1976 and 2007 and analyzed the changes among cropland, forest, shrubbery, natural grassland, waste-grassland, settlement place and so on. The result showed that because of the change of planting structure and species,the density of vegetation carbon changed greatly. The vegetation carbon storage increased 50.50×104 t C from 1976 to 2007. Then we find that different land types can be transferred to each other. Based on the above data, we calculated the impacts of cropland, forest, shrubbery, natural grassland and wasteland conversions on the vegetation carbon storage. It is found out that the vegetation carbon storage decreased 1.21×104t C due to land degradation and unlawful and uncontrolled felling of forests of the study area. At the same time, we found out that because a large area of unused land has been reclaimed as cropland, afforestation and conceding the cropland to forest and grass, the vegetation carbon storage increased 18.52×104 t C . The result showed that the total vegetation carbon storage was an increased trend, and we found out that the main factor, which affects the vegetation carbon storage, was cropland.
By using the daily surface temperature data of Ningxia, monthly characteristic values of 500 hPa circulation of the Northern Hemisphere, Arctic Oscillation Index (AOI) and NCEP/NCAR reanalyzed data during 1961-2008, the climatic characteristics of the variety of cold waves in Ningxia are analyzed, and the possible reasons for it are further discussed. The result indicates:the cold wave activities are distinct different in Ningxia different regions, and mainly occur in spring; in the recent 48 years, cold waves in Ningxia increased slightly in spring and autumn, decreased slightly in winter; the frequency of cold waves in Ningxia has negative correlation with AOI and temperature, positive correlation with the intensity of Siberian high, East Asian winter monsoon and the frequency of cold air activities invaded China, and the correlativity is obvious in autumn, winter and inconspicuous in spring; under the background of global warming, with the phase of AOI transformed from negative into positive from the end of 1980s, the intensity of winter Siberian high and East Asian winter monsoon has weakened, and made the surface temperature continue rising in Ningxia, this is one of the possible reasons for the decrease of Ningxia cold waves in winter; in spring, there has the similar variety but differs in the following points:the Siberian high played a more significant role in cold wave activities before the mid-1980s, while the impact of cold air activities on cold waves was more obvious with the continuou temperature rising after then; meanwhile, the Siberian high and the cold air activities impacted the cold waves more directly and more obviously in autumn. Studies also found, that with continued global warming, the impact of Arctic Oscillation on Siberian high and East Asian winter monsoon has weakened after the 21st century. Therefore, the mutual feedback among the Arctic Oscillation, Siberian high, the frequency of cold air activities, the East Asian winter monsoon and temperature is the possible reason for the variety of Ningxia cold wave frequency.
MODIS has the advantages of multi-band, high spatial and temporal resolution, which are propitious to the dynamic monitoring of a large area of arid regions. During late October 2008 and mid-February 2009, more than 10 provinces in east-central and northern China were hit by the severe drought. In this paper, Liaoning Province suffered the serious drought in early 2009 is selected as a study area. The drought information in MODIS data is extracted through the thermal inertia model, which is used to distinguish the range and the degree of the drought. In order to make a deep analysis of atmospheric structure characteristics and mechanism which led to this drought, wind direction, wind velocity, temperature, humidity and structure characteristics of atmosphere energy during this drought are revealed from two aspects: weather situation and Skew-T diagrams. The results show the main reason for this drought is the abnormal atmospheric structure,including the maintenance of dry cold air path caused by the strong and stable northeast cold vortex, the large temperature-dew point difference of the whole troposphere, the little water vapor in source area because of the northwest wind, the stable stratification and dry sink of atmosphere.
As a powerful tool for policy analysis, the Computable General Equilibrium Model has been introduced to study the regulation of water resources in Zhangye City. Based on this model, the study has simulated the changes of the operation of Zhangye economy as the production scale and products exportation of planting sector were controlled in different levels. It is shown that the restriction of the planting sector’s production scale and products exportation under current existing production conditions would be helpful to the allocation of water resources and the development of socio-economy in Zhangye City. However, compared to the restriction of the planting sector’s production scale, restriction of the planting sector’s products exportation could make Zhangye achieve better socio-economic benefits and ecological effects. The calculated results show that the limitation of the products exportation of planting sector would not only increase regional production, Gross Domestic Product and employment, but also save 77.5 million m3 of water from the regional production process, which could be used for the consumption of social life or construction of environment in the middle and lower reaches of the Heihe River Basin.
In order to make Ecological Footprint (EF) model better reflecting regional realities, the article significantly improved the calculating items of EF model. The arable land EF of meat and pollution EF of excreta of poultry, livestock and human were accounted firstly. Three EF categories, namely CO2 absorption forest, decomposition land and water collection area were established to show the seriousness of agricultural pollution and the multiple ecological functions of arable land and forest. Fossil-fuel land was contained by forest land for absorbing CO2; grazing land was canceled while the EF of grain used to produce meat was added arable land. The concerning pollution sources were expanded from fossil fuels to chemical-fertilizer, pesticide and excreta of poultry, livestock and human. Furthermore, the EF of pollutants such as CO2, N, P and pesticide was counted.Fujian’s agricultural EF in 2007 was calculated by using average yields per-unit in recent five years, including the EF of direct inputs, farmers’ consumption and pollutants in agricultural practice. The category comparison between agricultural EF and Fujian’s Ecological Capacity (EC) was used to reflect the agricultural ecological-occupancy in the province. The calculation results indicated that the agricultural EF of forest-land, wetland, built-up area and pollutants-absorption land occupied small proportion of Fujian’s EC in 2007, being respectively 1.4%, 1.2%, 13.4% and 24.6%. This was largely due to high ecological productivity in the province and low consumption in underdevelopment rural areas. However, 94.2% of arable land EC was occupied by agriculture because of less arable land areas per capita and overdevelopment in grain-consumption livestock, which consumed 73.8% of the arable land EC. The EF of water collection area was 2.2 times that of relevant EC, indicating that serious ecological deficit occurred. In water collection area category, chemical fertilizer, excretion and freshwater aquaculture contributed respectively 36.8%, 23.5%, 39.7% in N and 41.8%, 12.9%, 45.4% in P. Some corresponding suggestions were proposed.
The purpose of this paper gives an overview of the development of biotope mapping in nature conservation and urban-rural planning in the developed countries during more than 30 years. The definition and ecological functions of the biotope and two main approaches of the biotope mapping are introduced. Development and applications of biotope mapping in foreign countries during more than 30 years was elaborated. It primarily elaborated on three periods of biotope mapping development in foreign countries during more than 30 years: 1) initial biotope mapping (1974-1986); 2) development of biotope mapping (1986-1997); and 3) extended biotope mapping (1997-present). And three aspects applications of biotope mapping in nature conservation and urban-rural planning were identified: 1) species and habitat conservation; 2) land use planning and management; and 3) landscape planning and management. The problems and deficiencies in current biotope mapping studies were also discussed. The problems mainly focus on subjectivity in biotope investigation, map scales and application of GIS technology. It is found that biotope mapping has been a basic tool for nature conservation and urban-rural planning in foreign countries, because it is capable of offering basic, conservation- or planning-oriented and usable biological and ecological information about research area. Current situation and prospect of application of biotope mapping in nature conservation and urban-rural planning in China were also analyzed.
Taking Chaigou and Hejiagou watersheds of Wuqi County in Shaanxi Province as example, in the small watershed scale, discrepancy of biodiversity, biomass, community features and soil physical properties under approach of rehabilitation and abandonment were analyzed through vegetation and soil investigation of sample plot in ten years after returning farmland to forestry. The results showed that: in approach of rehabilitation and abandonment, structure of the herbal community is similar and the similarity coefficient is 0.925. In rehabilitation areas, summation cover and species of tree, shrub and herb layer is 99.03% and 85; average plant height of herb layer was 0.41 m, with indexes of species richness, diversity index, evenness of herb layer, were higher than in the natural restoration areas. But in rehabilitation areas, average biomass, community density, soil moisture, soil bulk density, capillary porosity were 5.890 t·hm-2, 8.11×105 ind·hm-2, 8.8%, 1.251g·cm-3 and 48.9%, lower than that in natural restoration areas. Change of coefficient of variation about soil indicators in two areas was complicated.
The hydrological uncertainty is one of the most important aspects in hydrological science research. This paper focuses on how resolution impacts the hydrological uncertainty using the TOPMODEL model based on the topographic index, which extracts from DEMs of different resolutions in the Hanjiang River. Three geomorphologic areas are selected as test areas, representing different terrain types from smooth to rough. Their DEMs are produced from digitizing contours of 1∶50000 scale topographical maps. Hydrological uncertainty was assessed synthetically by using the multiple-objectives fuzzy optimal method. It is found from the analysis on different spatial resolutions that the topographic characteristics parameters of river basin are affected by DEM resolution remarkably, so as to affect the hydrological uncertainty, but this effect is not very great due to the hydrological complexity, and 200 m should be the more suitable grid size for hydrological uncertainty in this area. The integrated method of assessing hydrological uncertainty is a new throughway to study the various hydrological uncertainties.
Based on the speciality of uncertainty and inaccuracy of precipitation, both simple statistical calculation and Markov chain theory were used together for predicting the precipitation in this paper. The method was characteristic of clear physical concept and simple calculation. Data of precipitation in Hangzhou, from 1956 to 2008, was used as an example. The precipitation can be predicted year by year using the statistical models;starting from the precipitation sequence data (1956—1995) in the last 40 years, the precipitation in 1996 was predicted, then the precipitation data in 1956 was removed and the actual data in 1996 was added to the sequence, and then in accordance with the basic steps of precipitation forecasts, precipitation in 1997 was predicted, and so on for each year of precipitation forecasts. Results show that the error value smaller than ±10％, ±15% and ±20％ was 30.77%, 53.85% and 69.23% respectively in the 13 years of precipitation prediction, and the maximum error value of the prediction was -24.03％. The precipitation can be predicted year by year using the statistical Markonian models;the error value smaller than ±1％ and ±5％ was 37.50% and 62.50% respectively in the 8 years of precipitation prediction, and the maximum error value of the prediction was 8.77％. The accuracy of precipitation prediction of the statistical Markonian models was improved obviously, hence a practicable method for predicting future precipitation was put forward.
