Western Mountainous Areas Research Articles

Comparison of hydrogeological characteristics and genesis of the Xiaguan Hot Spring and the Butterfly Spring in Yunnan of China

The Xiaguan Hot Spring and the Butterfly Spring near Dali in Yunnan of China were sampled 5 and 3 times, respectively and their hydrogeological characteristics are discussed in this study. The TDS and hydrochemical type of these two springs are 1360 mg/L and HCO3-SO4-Na type, and 246 mg/L and HCO3-Ca-Mg type, respectively. The Butterfly Spring is enriched in Ca2+, Mg2+ and HCO3− due to dissolution of carbonate rocks. In contrast, the Xiaguan Hot Spring is enriched in Na+, K+, HCO3− and SO42− due to dissolution of albite, halite and ion exchange. The concentrations of the rare earth elements (REEs) in the Xiaguan Hot Spring and the Butterfly Spring range from 0.033 μg/L to 0.071 μg/L and 0.013 μg/L to 0.018 μg/L, respectively. The absolute concentrations of the medium rare earth elements (MREEs) and heavy rare earth elements (HREEs) are relatively higher than those of the light rare earth elements (LREEs) in the Xiaguan Hot Spring. The concentrations of the LREEs in the Butterfly Spring are relatively high. The δ2H and δ18O values of the Xiaguan Hot Spring and the Butterfly Spring vary from −102‰ to −107‰ and −11.6‰ to −13.8‰, respectively, showing negative trends due to altitude effect. The data points of δ2H and δ18O of the two spring samples are close to the Global Meteoric Water Line and the Local Meteoric Water Line with a slight 18O shift, indicating that the springs are meteoric in origin with a slight 18O exchange with the surrounding rocks. The geothermal reservoir temperature of the Xiaguan Hot Spring estimated with SiO2 geothermometers ranges from 107.4 °C to 114.6 °C. The Xiaguan Hot Spring occurs in the metamorphic rocks of the Paleoproterozoic Cangshan Group, and is recharged from infiltration of precipitation and snow-melting water. After undergoing a deep circulation, the groundwater is heated by heat flow and rises along the Tangzipu fault to form a hot spring of deep groundwater circulation type. The Butterfly Spring emerges in the Silurian limestone. Groundwater receives recharge from precipitation and snow-melting water in the western mountainous area, flows eastward along the fissures, and emerges on the lower slopes as a spring of shallow groundwater circulation type with ambient temperature.

Falsification‐Oriented Signature‐Based Evaluation for Guiding the Development of Land Surface Models and the Enhancement of Observations

AbstractWe develop a novel framework for rigorously evaluating land surface models (LSMs) against observations by recognizing the asymmetry between verification‐ and falsification‐oriented approaches. The former approach cannot completely verify LSMs even though it exhausts every case of consistency between the model predictions and observations, whereas the latter only requires a single case of inconsistency to reveal that there must be something wrong. We argue that it is such an inconsistency that stimulates further development of the models and enhancement of the observations. We therefore propose a falsification‐oriented signature‐based evaluation framework to identify cases of inconsistency between model predictions and observations by extracting signatures based on a set of key assumptions. We apply this framework to evaluate an ensemble of simulations from the Noah‐MP LSM against observations over the continental United States under the three assumptions of water mass conservation, no lateral water flow, and a sufficiently long period of time. Regions showing inconsistencies between the Noah‐MP ensemble simulations and the observations are located in the western mountainous areas, the Yellowstone river basin, the lower Floridan aquifer, the Niobrara river basin at the north tip of the Ogallala aquifer, and the basins downstream of the Balcones fault zones in Texas. These regions coincide with the sites where both advances in theoretical modeling and new observational data (e.g., from the Critical Zone Observatories) have emerged.

Regional Sustainable Assessment at City Level Based on CSDIS (China Sustainable Development Indicator System) Concept in the New Era, China

The core issue of sustainable development refers to the coordinated development of economic-social-environmental issues. In the present study, by complying with the China Sustainable Development Indicator System (CSDIS) concept, a comprehensive index system was built; besides, Natural Breaks (Jenks) Classification Method, Exploratory Spatial Data Analysis and Geographic Detector Analysis were conducted to delve into the sustainability and coordinated degree at city level in China from 2007 to 2017. The achieved results are presented as follows. First, for spatial differentiation, the overall spatial distribution pattern was characterized by the high-value units in eastern China and the low-value units in western China from 2007 to 2017. To be specific, the high-value units were radiated along the Beijing-Guangdong Axis (Jing-Guang Axis) centered on the core of Beijing-Tianjin-Hebei Region, the middle-value units were distributed in strips along the coast, and the low-value units were vastly gathered in western China and gradually break via the Hu Huanyong line (Hu Line) in south China from 2007 to 2017. More specifically, based on the five subsystems, the pattern of each system was consistent with the whole, whereas the degree of concentration was different. Second, for spatial correlation, the significant High-High (HH) areas were primarily distributed in the core of Beijing-Tianjin-Hebei, Yangtze River Delta and Pearl River Delta Regions. The significant Low-Low (LL) areas were continuously distributed in the southwest China and broke through the Hu Line from 2007 to 2017. There were insufficient number of significant High-Low (HL) and significant Low-High (LH) areas, whereas the spatial agglomeration of them was less obvious. Third, for internal coupling coordination, the spatial differentiation between the coupling degree and the coupling coordinated degree was significantly consistent in 2007 and 2017. The Beijing-Tianjin-Hebei, Yangtze River Delta and Pearl River Delta Regions have demonstrated a high level of coordinated evolution, and the pattern of western mountainous areas exhibited a low degree of coordinated growth. Lastly, based on the combination of quantitative and qualitative, its factors were underpinned by robust economic strength, the vitality support of the information level and the basic support function of the topography, active guidance of national policies and path dependence and industrial transfer.

Assessment of the Impact of PM2.5 Exposure on the Daily Mortality of Circulatory System in Shijiazhuang, China

Air pollution can increase the morbidity and mortality of cardiovascular and cerebrovascular diseases, but there are few related studies in counties and cities with serious pollution in China. China is at a critical stage of environmental pollution control. Assessing the health impact of PM2.5 (particulate matter with a diameter equal or lower than 2.5 micrometers) on the death toll from cardiovascular and cerebrovascular diseases in heavily polluted counties and cities is of great importance to the formulation of air defense policies related to PM 2.5. Generalized additive models (GAMs) were used to analyze the effects of PM2.5 exposure on the death toll of circulatory system diseases in 16 districts, counties and cities in Shijiazhuang from 2014 to 2016 after controlling the long-term trend of the time series, seasonal effects, holiday effects, air temperature, relative humidity and other factors. The average PM2.5 concentration was 121.2 ± 96.6 μg/m3; during the corresponding period, the daily mean mortality of circulatory system diseases in Shijiazhuang was 4.6 ± 4.7. With the increase of PM2.5 by 10 μg/m3, the risk of total death from circulatory system diseases with a lag of two days (lag02) increased by 3.3‰ (95% confidence interval (CI): 1.0025, 1.0041). The relative risk (RR) of the effect of PM2.5 exposure on the death toll of the circulatory system in Shijiazhuang is consistent with the spatial distribution of the PM2.5 concentration and the mortality of circulatory system diseases: the RR of the eastern plain with heavy pollution and a relatively dense population is high, while the RR of the western mountainous area with relatively light pollution and a relatively sparse population is low. For every 10-μg/m3 increase of PM2.5, the risk of the increasing death toll from circulatory system diseases in Luancheng of the eastern plain is the highest at 11.9‰ (95% CI: 1.0071, 1.0168), while the RR of Pingshan of the western mountainous area is the lowest at 2.1‰ (95% CI: 0.9981, 1.0062). Conclusions: Based on the epidemiological analysis and GAMs model, after controlling for other confounding factors, PM2.5 exposure increased the death risk of the circulatory system in Shijiazhuang, and the risk is higher in heavily polluted plain areas. It provides a scientific basis for formulating scientific air pollution prevention and control policies and provides a reference for improving the prevention awareness of sensitive groups.

How imbalanced land development affects local fiscal condition? A case study of Hubei Province, China

Aiming at realizing the efficacy and fairness of spatial allocation of land resources, zoning is one of the most widespread tools adopted by governments around the world. However it also brings imbalanced land development which will lead to the "windfall-wipeout dilemma" of stakeholders. Local government regarded as the regional governor and economic driver, is an important part of stakeholders, and will fall into fiscal dilemma when the land development is restricted. In this paper, we discuss how imbalanced land development affects local fiscal condition based on the theory of farmland preservation externality and finance and taxation system. Taking Hubei Province as an example, the degree of imbalanced land development, and the relationship between local fiscal condition and imbalanced land development are quantified by employing a panel dataset of 88 local jurisdictions (counties or districts) from 2009 to 2014. The results show that: (1) The degree of imbalanced land development in Hubei Province is 0.260 with characteristics of temporal decrease and spatial increase from high urbanized eastern areas to middle, northern agricultural dominate areas to low urbanized western mountainous areas. (2) The imbalanced land development aggravates the local government fiscal difficulty, the higher degree of imbalanced land development, the more serious the fiscal condition is. Therefore, innovation of trans-regional fiscal payment on the basis of the degree of imbalanced land development can effectively address the local fiscal dilemmas and achieve regional coordinated development.

Changes in seasonal and diurnal precipitation types during summer over the upper reaches of the Yangtze River Basin in the middle twenty-first century (2020–2050) as projected by RegCM4 forced by two CMIP5 global climate models

Changes in summer and diurnal precipitation in the upper reaches of the Yangtze River Basin (UYRB) in the middle of the twenty-first century were estimated by RegCM4 with a resolution of 50 km under two representative concentration pathway scenarios. ERA-Interim, CSIRO-MK3.6.0 and MPI-ESM-MR were used as the initial and lateral boundary conditions, and two observation data sets (CN05.1 and CRU) were used to evaluate the precipitation performance. RegCM4 captured the spatial characteristics of summer precipitation in the UYRB during the reference period. Compared with the two observational data sets, the three groups of downscaling results underestimated the precipitation in the eastern part of the basin by 20% and overestimated that in the west by more than 80%. In the middle of the twenty-first century, the total precipitation (TPR) in the UYRB varied significantly from east to west. The multiyear average TPR in the eastern plains was projected to significantly decrease, while it significantly increased in the western mountains. As a major contributor to the TPR in the UYRB, convective precipitation (CPR) differed between the eastern and western regions, especially at night. The TPR changes in the east (decrease) and west (increase) were projected to be strongest in the afternoon. The probability of high-intensity precipitation in the central and western areas will increase, implying a potential increase in the risk of flooding in these areas. The diametric changes in the TPR between the east and west may further exacerbate the spatial heterogeneity of water resources, resulting in large impacts to surface hydrological processes. The spatial variations in precipitation were mainly due to the variation in precipitation mechanisms between the western mountainous area and the eastern basin, while the changes in water vapour transport and atmospheric stability also played a role.

Influence of water and rock particle contents on the shear behaviour of a SRM

Abstract The contents of both water and rock particles are important factors affecting the mechanical strength of a soil–rock mixture (SRM) filled subgrade in the western mountainous area of China. Therefore, the purpose of this paper is to study the mechanisms of reconstituted landslide deposit samples with different water and rock particle contents by analysing the characteristics of shear strength, volumetric strain and ‘jumping’ phenomenon via large-scale direct shear tests. The results show that the influence of water content on shear strength is greater than the influence of rock particle content under a lower normal stress, and the results are reversed in the case of a higher normal stress. The effect of water content on the equivalent cohesion is bigger, especially for the sample with a high rock particle content. The friction angle of the specimen with same water content increases with the increasing rock particle content, but when the number of rock particles increases to a certain extent, there is a little effect on the friction angle. However, the friction angle decreases with increasing water content at the same rock particle content. Specimens with the same rock particle content change from dilation to compression with increasing water content. Finally, the continuous stage of the ‘intense jumping’ at different water content has been analysed. The ‘jumping’ phenomenon of samples with low water and rock particle content will first strengthen and then weaken the samples with increasing normal stress.

Identifying Dynamic Changes in Ecosystem Services Supply and Demand for Urban Sustainability: Insights from a Rapidly Urbanizing City in Central China

Identifying the balance and dynamic changes in supply and demand of ecosystem services (ES) can help maintain the sustainability of the regional ecosystem and improve human well-being. To achieve a sustainable ecological management regime in Zhengzhou City, this study presented a comprehensive framework for identifying dynamic changes of ES supply and demand and managing ES. Using land use data of Zhengzhou City in 1995, 2005, and 2015 and incorporating expert knowledge and the ES evaluation matrix, we evaluated the spatiotemporal changes in the ES supply and demand in Zhengzhou. Gradient analysis was conducted to identify urban–rural patterns in the budgets of ES supply and demand. Spatial autocorrelation analysis was employed to identify the hotspot areas of ES surpluses or deficits. The research results show the following: (1) In the past 20 years, the supply-and-demand relationship of ES in Zhengzhou has gradually evolved in a direction where supply falls short of demand. The average budget index of Zhengzhou’s ES supply and demand decreased from 7.30 in 1995 to −4.89 in 2015. Changes in the supply and demand status of ES in Zhengzhou corresponded to the background of rapid urbanization. (2) Urban–rural gradient differences exist in the budgets of ES supply and demand in Zhengzhou. Core development areas, such as the Zhengzhou urban areas, are in deficit, whereas a balance or surplus can be observed in rural areas far from urban centers. (3) The surplus hotspots of ES budgets were mainly distributed in the western and southern mountainous areas of Zhengzhou, and they were scattered and the scope shrank, with a decrease of 2.73 times in 20 years, whereas the deficit hotspots expanded outward with each urban area as the center, with an increase of 5.77%. Ecological management zoning (ecological conservation area, ecological improvement area, and ecological reconstruction area) with the effective guidance of ecological and economic policies could comprehensively improve ES management and achieve urban sustainability. The framework in this study can easily and quickly assess the supply and demand status of ES and provide scientific support for the ecological management in rapidly urbanizing areas.

Integrating spatial continuous wavelet transform and kernel density estimation to identify ecological corridors in megacities

Ecological corridors are effective to prevent ecosystem degradation and biodiversity loss through promoting the connection among discrete habitat patches. Identifying ecological corridors is of great importance for biodiversity conservation and landscape planning. Previous studies mainly focused on the directions of ecological corridors among habitat patches and the boundaries of ecological corridors were usually subjectively identified. In this study a new approach integrating spatial continuous wavelet transform and kernel density estimation was proposed to objectively identify the width thresholds of ecological corridors in the megacity of Beijing City, with the application of InVEST model to extract core habitat patches, and constructing the ecological resistance surface based on natural conditions and human activities. The restoration coefficient was also defined and applied to determine the key restoration areas. The results showed that the total area of core habitat patches in Beijing City was 3652.75 km2, with 1414.67 km2 for ecological corridors, mainly distributed in the western and northern mountainous areas. 36 key restoration areas were also extracted, mainly located in the narrow areas with large resistance. Identifying the range and key restoration areas of ecological corridors can provide spatial guidelines for ecological conservation and restoration, thus ensuring regional ecological security in megacities.

Analysis of the Onset and Mortality of Common Malignant Tumors Among Registered Residents in Xishan District in 2016

Objective: To analyse the cancer incidence and mortality in xishan district in 2016, and to provide scientific basis for tumor prevention and control. Methods: The 2016 malignant tumor registration report data in xishan district were collected and analysed, stratified according to gender and age, and the reported incidence of malignant tumor in xishan district was calculated and analysed (all the following incidence rates belong to the reported incidence), gender, age incidence, bid acceptance rate, mortality and other related indicators. Results: The total registered population of malignant tumor in xishan district in 2016 was 540,494 (268 553 males and 271 941 females), and 876 new cases were reported. The incidence rate was 162.07/105, the bid-winning rate was 176.39 /105, the world standard rate was 91.16/105, and the cumulative rate (0-74 years old) was 10.44%. The incidence of malignant tumors in males (159.00/105) was lower than that in females (165.11/105). Incidence increases with age, rises sharply and rapidly around age 40, and declines after reaching a peak at age 75. Lung cancer, colorectal cancer, thyroid cancer and female breast cancer are common malignant tumors in the western mountainous areas. It accounts for about 55% of the total number of new malignant tumors. In 2016, 653 people died of malignant tumors in xishan district. The mortality rate was 120.82/105 (male mortality 151.11/105, female mortality 90.46/105), the bid-winning mortality rate was 43.53/105, and the bid-winning mortality rate was 57.72/105. Lung cancer, liver cancer, colorectal cancer and stomach cancer are the malignant tumors with high mortality, accounting for about 62% of the death. Conclusion: The morbidity and mortality of malignant tumors are relatively high in xishan district, and prevention and control of lung cancer, liver cancer, stomach cancer, colorectal cancer, female breast cancer and thyroid cancer should be emphasized.

Reinforcement scheme design for geotechnical slope engineering

With the continuous development of western mountainous areas and the deepening of infrastructure construction, geotechnical slope has become an engineering problem that cannot be ignored in the process of construction and using. Due to its universality and great harm of accidents, it has become a hot spot that engineers and researchers pay more attention to. It is of great significance to strengthen the stability of geotechnical slope.There are mature theories at home and abroad, but the actual engineering geological conditions are complex, the combination of theory and practice still needs to be explored. Combined with the slope engineering of an airport in the loess plateau area, the engineering geological conditions and the current situation of the slope were firstly introduced in this paper, then the stability checking was carried out under natural working condition and heavy rain condition respectively. The slope reinforcement was carried out for Scarp 1 and Scarp 2, respectively. This paper is of great help to further understand the principle of slope engineering reinforcement and can provide experience for slope reinforcement under similar working conditions.

Study on seismic performance of high pier multi-span beam bridge

Girder bridge with high piers has obvious advantages in crossing deep gorges, and is commonly applied to highway construction in the western mountainous area of China. In Qinghai province, the earthquake response is very complicated, and the seismic design is absolutely necessary. In this paper, the seismic performance of the typical span of a high-pier-girder bridge in seismic zone of Qinghai province is analyzed by the time-history analysis method based on the existing seismic design code. The seismic response characteristics and development rules of the bridge are obtained, and the methods to effectively improve the integrating stiffness and seismic performance of the bridge are discussed. The results can provide references for the seismic design of the same kind of bridges.

Pore structure characteristics of debris flow source material in the Wenchuan earthquake area

Wide-grading loose soils (WGLS) are a special slope deposit that often serve as a source for debris flows in the western mountainous area of China. Previous research indicated that rainfall infiltration induced the migration of fine particles within soil slopes and lead to the initiation of shallow failure and subsequent debris flows. Clearly, soil pore structure exerts a profound influence on seepage during rainfall infiltration, which is closely related to soil permeability and corresponding internal erosion. The current understanding of the mechanisms of fine particle migration is limited because of the complexity of WGLS micropore structure. The challenge lies in how to systematically characterize WGLS pore structure so that it provides a foundation for future numerical simulations of fine particle migration-induced debris flows. In this study, the characteristics of WGLS pore structure were analyzed quantitatively using scanning electron microscopy. The results revealed that WGLS predominantly contained micropores and mesopores. The pore size distribution exhibited a bimodal nature with one peak occurring at a pore diameter of 12 μm and another at 72 μm. The pore complexity of all samples exceeded 0.75, which indicates a low aspect ratio for each pore. The average diameter of the fine particles that migrated was then determined with a laboratory seepage test. A preliminary jamming probability analysis based on three-dimensional micropore reconstruction and average fine particle diameter indicate that jamming is most prevalent along the slope.

Estimating Housing Vacancy Rates in Rural China Using Power Consumption Data

Village hollowing is a growing policy problem globally, but accurately estimating housing vacancy rates is difficult and costly. In this study, we piloted the use of power consumption data to estimate the vacancy rate of rural housing. To illustrate the method used, we took power consumption data in 2014 and 2017 in an area of rural China to analyze the change in housing vacancies. Results indicated that the rural vacancy rates were 5.27% and 8.69%, respectively, while underutilization rates were around 10% in 2014 and 2017. Second, there was significant spatial clustering of vacant rural housing, and the hotspots were mainly distributed in western mountainous areas, whereas villages near urban areas had lower vacancy rates. Third, rural vacancies increased from 2014 to 2017. Compared with other methods, our method proved to be accurate, very cost-effective and scalable, and it can offer timely spatial and temporal information that can be used by policymakers to identify areas with significant village hollowing issues. However, there are challenges in setting the right thresholds that take into consideration regional differences. Therefore, there is also a need for more studies in different regions in order to scale up this method to the national level.

Application on Machine Learning Method in Accurate Identification of Poverty Alleviation Objects—Taking the Survey Data of Residents in Certain Western Mountain Area as an Example

The government has an important duty, that is, reducing the social poverty, so how to recognition poverty alleviation objects becomes a critical factor. We selected the province western mountain area for the location of sampling, selecting index designed questionnaire to conduct on-the-spot investigation, collection of mountainous area residents family specific data, using the method of multidimensional poverty measure UNDP-MPI ideas of poverty indicators for dimensions, using the analytic hierarchy process (AHP) to empowerment of multidimensional index, multidimensional poverty measurement model is established. The multidimensional poverty measurement model is used to identify the poor families. Finally, the multidimensional poverty measurement model is fitted and verified with the single income index model, so as to determine the effectiveness of the multidimensional poverty measurement model and solve the problem of poor households' inefficient identification.

Aneuploid Chromosome Constitutions of the Small Japanese Field Mouse, Apodemus argenteus, in the Western Mountainous Area of Kanagawa Prefecture, Honshu, Japan

Abstract. We studied an occurrence of chromosomal aneuploidy for ten individuals in the small Japanese field mouse, Apodemus argenteus, from the western mountainous area of Kanagawa Prefecture, Honshu, Japan. Eight of the individuals examined showed the standard 2n = 46 and FNa = 48 constitutions as the most frequent karyotype. However, of those eight individuals, seven carried an inter-cellular mosaicism with a few metaphases carrying a small-sized supernumerary element. In addition, one individual showed an aneuploid complement that included a small-sized bi-armed B chromosome (2n = 47). The B chromosome consisted of the C-heterochromatin and was characterized by delayed fluorescence by the quinacrine mustard staining, suggesting that its feature is identical to the B chromosomes previously confirmed in other localities. Moreover, an XO female showing a standard autosomal complement with only one X chromosome (2n = 45, XO) was also recognized. According to the present observations, these chromosomal aneuploidies are retained in wild populations of A. argenteus as constantly occurring phenomena.

Comparison of wind characteristics at different heights of deep-cut canyon based on field measurement

The typical U-shaped deep-cut canyon is widely distributed in the western mountainous areas of China, especially in Sichuan province and Yunnan province. The deep-cut canyon has the characteristics of the high drop in elevation, high-temperature difference, and complex wind environment. A 50 m high meteorological mast with a total of eight anemometers was erected in such topography, and a long-span suspension bridge will be constructed in the area where the meteorological mast is located. Based on the long-term monitor data, the wind characteristic parameters including average and fluctuating wind characteristics and coherence between different heights are investigated. The results are as follows. The dominant wind direction which depends on the topography is north–south. The attack angle of wind is mainly less than zero, and its probability distribution obeys the hypothetical Gaussian distribution. Both the increases in height of anemometer and in wind speed reduce the dispersion of the attack angle of wind. The gust factor has a similar change law of attack angle of wind. Turbulence intensities are affected by the height of the anemometer and the wind speed, and they are different from the recommended value of China Codes. In terms of turbulence integral length scale, the value increases with an increase in the height of the anemometer in the same component. The largest value occurs in the longitudinal direction and the smallest occurs in the vertical direction at the same level. The coherence between any two locations is relatively strong, and the longitudinal component is stronger than others. The measured wind power spectrum for longitudinal, lateral, and vertical wind in deep-cut canyon fits the von Kármán model better.

Relationship between stand characteristics and soil properties of two typical forest plantations in the mountainous area of Western Sichuan, China

There is uncertainty and limited knowledge regarding stand characteristics and soil properties of middle-aged pure forest plantations in the mountainous area of Western Sichuan. Plantation forests are almost exclusively planted as monocultures in the Pengzhou forest farm in the western mountainous area of Sichuan Province. This study aimed to assess the spatial and ecological characteristics of middle-aged Cunninghamia lanceolata (Lamb.) Hook. and Cryptomeria fortunei Hooibr. in the Pengzhou forest farm. The relationships and differences between stand growth characteristics and forest soil composition were assessed on the two forests planted simultaneously within the same area and exposed to the same environmental conditions. Cr. fortunei grew sparse, and slower than Cun. lanceolata. Principal component analysis indicated that the soil properties in the Cr. fortunei plantation were better than those in the Cun. lanceolata plantation. Redundancy analysis revealed that the differences in stand structure were affected significantly by the total nitrogen content and pH value. Thus, we propose that Cr. fortunei is planted for priority consideration in the subtropical high mountain area. Further, tending operations and application of fertilizers need to be conducted in Cun. lanceolata forests. Based on theoretical and experimental data, the present study explains why local farmers are more willing to plant Cr. fortunei, and thus provides a useful theoretical reference for the development of sustainable plantations in the future.

Dynamic Change Characteristics of Groundwater Affected by Super-Long Tunnel Construction in the Western Mountainous Area of China

The problem of groundwater is very prominent in super-long tunnel construction, which brings serious potential safety hazards and economic losses to the project. The knowledge of dynamic change characteristics of groundwater and prediction of water inflow is the key to ensure rational design and safe construction in super-long tunnel. In this paper, numerical simulation and in situ observation are conducted to investigate dynamic change characteristics of groundwater and the prediction of water inflow based on the Daxiangling tunnel in Sichuan Province of China. The results show that the numerical model established with detailed geological data and validated with field monitoring data can effectively analyze dynamic change characteristics of groundwater, as well as predict water inflow. The initial state of groundwater is steady when the tunnel is unexcavated. Tunnel excavation has a significant influence on the distribution of groundwater. The flow direction of groundwater will change, and the contour lines of groundwater will be intensive at the tunnel face. These changes will be more obvious and dramatic when the tunnel is excavated into the fault zone, which is a signal that the water inrush is more likely to occur in the fault zone because of a lot of joints and fractures. A connected linear cavity is formed with tunnel holing-through and groundwater begins to flow vertically downwards to the tunnel. As far as the prediction of water inflow is concerned, the numerical method can more precisely calculate the value of water inflow with less than 15 percent relative error compared with the groundwater dynamics method.

FUNCTIONAL CONNECTIVITY ANALYSES AND CONSTRUCTION STRATEGIES OF THE STRUCTURE OF GREEN SPACE NETWORK IN HAIDIAN DISTRICT OF BEIJING

Urban green space structure and pattern have been one of the highlights in Landscape Architecture studies, accompanying with urgent demands of promoting ecological spatial structures in urban construction. Focusing on functional connectivity and construction strategies of the structure of green space network in Haidian District of Beijing, this research builds resistance surface and identifies linkages through habitat quality evaluation of the InVEST Model and the simulation with the Least-Cost Model, while adopting functional connectivity index (NL, NC, IIC, PC, and dIIL) to indicate the structural characteristics of green space network at varied distance thresholds. Results reveal that, on the whole, the distance threshold of 2,200 meters is most appropriate for the structure of the existing green space network of Haidian District, when 10 components and 353 linkages are identified and six important nodes and three important linkages that require a protection priority are further determined. Findings also disclose that the forest network of target tree species and that of water network of target water bird species are highly fragmented. Forest network serves in forms of dominant patch structure, local network structure, and fragmented cluster structure in the western mountainous area, the northern plain area, and the southeastern urban area, respectively. Moreover, the research proves that by introducing ten important linkages, the connectivity of forest network can be improved by 1.7 times, completing the overall structure in multiple directions and helping form a stable and resilient structure of the network. Finally, the research puts forward strategies for urban green space construction, including identifying construction objectives and target species, identifying and protecting important nodes and important linkages, and introducing possible important linkages and improving the structure of green space network, to help efficiently improve urban ecological quality.