The reform in water pricing plays a critical role in agricultural production, which is believed to have great water savings potential. We consider eliminating irrigation subsidies as a simulation and conduct a comparative evaluation between the water parallel pricing system (WPPS) and the water pricing system (WPS), which are incorporated into two computable general equilibrium (CGE) models, respectively. The results prove that, compared with WPPS, WPS would contribute higher capacities for water savings with more farming imports and less loss in farming output; households in rural and urban areas would benefit from more income and food consumption, which would be matched by increasing farming imports. A policy recommendation is that eliminating the irrigation subsidy should pay more concerns on alleviating the negative effects on farming outputs. Moreover, improvements in agricultural labor mobility and water demand elasticity are needed to enable more focus on the water conservation policy, particularly in WPS.

Transport is a major component of energy consumption and CO2 emissions in travelling. Understanding changes in the energy efficiency of tourism transport (EETT) and factors affecting this is important to the promotion of low-carbon tourism. This paper established a new method following the top to bottom principle and analyzed EETT variation characteristics and influencing factors from 1994 to 2013 in China. We found that the energy consumption of tourism transport (ECTT) increased from 178.21 PJ in 1994 to 565.82 PJ in 2013 at an average annual growth rate of 6.27%; CO2 emissions of tourism transport (CETT) went up from 14.96×10⁶ t to 47.94×10⁶ t due to person-trip and trip distance growth. EETT went from 3.22×10⁶ person-trips PJ^-1 in 1994 to 5.99×10⁶ person-trips PJ^-1 in 2013 at an average annual growth rate of 4.90%, and the CO2 emissions of tourism transport unit person-trips (CETTU) shifted from 26.07 kg person-trips^-1 in 1994 to 14.01 kg person-trips^-1 in 2013. Energy intensity decline, scale effects and policy promotion were key factors that enhanced EETT. Meanwhile, trip mode changes and enjoyment-oriented transport hindered EETT. Based on our analysis, we suggest methods to decrease ECTT and CETT, and enhance EETT.

In developing countries, various plans are used to contain urban sprawl of large cities, though they are rarely successful. Previous studies mainly attribute the failure to unsystematic urban planning, problems of governance or implementation, and rapid economic development. We suggest that an underestimation of urban population numbers is also a key factor, and that population forecasting methods currently in use need to be revised. Using panel data covering 110 major countries across 60 years (1950–2010), this study examined the relationship between large cities, and countries' population numbers, urbanization rate, land area, and four dummy variables. Based on this, a simple and generalizable model is developed to project the population of large cities.

Our ecosystem provides us with essential services, most of which come without a price tag and hence are assumed to be “free gifts of nature” available in plenty. Much of the neoclassical thought and analysis was based on this assumption until recently. The dynamic rise in population due to rapid industrialisation and urbanization has caused the realisation that ecosystem services are also limited. Environmental degradation is a common term used to describe the loss or impairment of ecosystem services. Migration is often a consequence of environmental degradation; when ecosystem services are impaired and survival comes at stake. But is the degradation of essential ecosystem services sufficient to motivate people to relocate? Through a review of literature on migration and environmental degradation, this paper strives to answer the above question along with exploring ways how monitoring the deterioration of the environment on time can spare human inhabitants of any ecosystem the pains of migration in search of better means of survival and sustenance.

Vegetable yields have increased in China because of the increasing demand for vegetables; however, chemical contamination present in vegetable fields threatens food safety in China. Based on the data for the areas under cultivation and yields of vegetables and grains, price indices for agricultural production inputs, agricultural materials per unit area, producer price indices and net profits from vegetable and grain production, the potential for food safety risks in China caused by contamination of vegetable fields was analyzed based on comparison between vegetables and grains of areas under cultivation, yields, net profit, and agricultural materials use per unit of area. The author found that the area under cultivation and yield of vegetables have significantly increased because of increasing public demand for vegetables in the diet and high market prices for vegetables since the initiation of socialist market economy reforms; however, the potential risk from the application of agricultural materials increased during the study period as the proportion of vegetable planting increased. Food safety in China could be improved by controlling contamination in vegetable fields.

In order to test whether density dependence influences community diversity, a combination of manipulative experimentation and plot surveys were done using Cryptocarya concinna, a dominant species in subtropical evergreen forest. Twelve pairs of 1 m² seedling plots were built around 12 adults, and plots were treated monthly with either a fungicide or a control. The surviving proportion of C. concinna seedlings at different stages was calculated, and an analysis was conducted on the impact of fungicide on seedling survival and species richness. Correlation between relative abundance and community evenness at different ages was analyzed using plot surveys. The results showed that fungicide treatment decreased species richness of the seedling community by promoting the recruitment of common species. Furthermore, census of a 25 m radius around adult C. concinna trees confirmed that the density of saplings increased with distance from adults. Relative abundance of C. concinna decreased with increasing age, and decreasing C. concinna dominance resulted in an increase in community evenness. To avoid the appearance of a single optimum population, the dominance of C. concinna decreased with age via density dependence, and subsequently improved community species diversity.

The littoral zone of freshwater ecosystems is believed to be a hotspot for methane (CH₄) emissions, but in situ measurements are rare. This paper reports a study of CH₄ fluxes from the Miyun Reservoir near Beijing in China based on an integrated observational and modelling approach. CH₄ fluxes were measured at three sites with different water levels containing nine representative vegetation communities. A process-based model, Wetland-DNDC, was tested against observations for its applicability in simulating CH₄ fluxes from the littoral zone of the reservoir. The R² values, which showed correlation between the modeled and observed results, were 0.89, 0.81 and 0.49 for the deep water, shallow water and seasonally flooded sites, respectively. The modeled data indicated that the observed CH₄ fluxes were mainly driven by water level fluctuations, soil temperature and soil organic matter content. The modeled average annual flux from the littoral zone of Miyun Reservoir was 15.1 g CH₄.m^-2, which was comparable with other studies in China. Our study suggests that Wetland-DNDC is a suitable choice as a model for CH₄ flux simulation from littoral zone of reservoirs or lakes, although improvements in the vegetation module could enhance the model's accuracy and applicability.

The process of rapid urbanization in China features two opposing trends: declining rural population and increasing rural residential land, especially in southern hilly areas. The extraction and analysis of residential land in rural China represents an important application for remote sensing technology. The study aimed to discover rural residential land information using RapidEye satellite imagery, taking Taihe County as the research area in the hilly region of southern China. Based on multiple experiments, classification was conducted with an optimal image segmentation scale set to 200. The object-oriented classification rule set was constructed using the customized parameters NDVI, NDWI, brightness, and length/width. The areas of residential land and other land use types were interpreted by varying the parameter values for classification rule sets. Finally, validation and accuracy evaluations were carried out. The overall accuracy of residential land interpretation is 78.40%, and producer's accuracy and user's accuracy are 68.75% and 77.33%, respectively. The results indicate that RapidEye provides a suitable data source for extraction of rural residential land using an object-oriented approach. Compared with the second national land survey of China, the classification gave an absolute difference of 93.67 ha residential land within the study area. Recognition errors occurred mainly in regions adjacent to the boundaries between residential land and other types of land.

Forests are fundamental to maintaining ecological security and achieving regional sustainable development in China. Forest land change can result in many ecological problems including soil erosion, water shortages, drought and biodiversity loss. Based on landscape ecology and logistic regression we explored the spatiotemporal patterns and factors affecting forest land changes from 1985 to 2000 in the Beijing-Tianjin-Hebei Region of China. The results show decreased local fragmentation of woodland landscapes and that the shapes of forest patches have become more regular. For forest land cover change, soil organic matter content, slope type I (<5°), distance to the nearest village and per capita GDP were the most important independent variables from 1985 to 2000. This study indicates that spatial heterogeneity can affect the predictability of logistic regression models for forest land change.

Decentralized sewage treatment systems are commonly used in rural areas of China because these systems are low cost, easy maintenance and high efficiency. However, as awareness of the importance of sustainable development has increased, questions concerning how to evaluate the sustainability of these systems has become a key point. In this study, emergy analysis is applied to evaluate the soil rapid infiltration for a decentralized rural sewage treatment plant that is located in Dongzhuangtou village, Qingdao, China. The results show that the environmental load ratio and the emergy sustainability index of the system are 0.07 and 242.88, respectively. The net economic benefit is 2.17E 18 sej·year-1 when converted into solar emjoule. Compared to other treatment systems, the environmental load ratio of the system is lower, and the emergy sustainability index is higher. This study reveals the reuse of treated water can produce great economic benefits in the soil rapid infiltration system. The environmental impact of the system is lower, and the sustainability is higher than that of other treatment systems. This result provides a quantitative evaluation of the sustainable development of rural sewage treatment systems in China.