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1.
Aiming for the restoration of degraded ecosystems, many ecological engineering projects have been implemented around the world. This study investigates the ecological engineering project effectiveness on vegetation restoration in the Beijing-Tianjin Sand Source Region(BTSSR) from 2000 to 2010 based on the rain use efficiency(RUE) trend in relation to the land cover. More than half of the BTSSR experienced a vegetation productivity increase from 2000 to 2010, with the increasing intensity being sensitive to the indicators chosen. A clear tendency towards smaller increasing areas was shown when using the net primary productivity(NPP, 51.30%) instead of the accumulated normalized difference vegetation index(59.30%). The short-term variation in the precipitation and intra-seasonal precipitation distribution had a great impact on the remote sensing-based vegetation productivity. However, the residual trends method(RESTREND) effectively eliminated this correlation, while incorporating the variance and skewness of the precipitation distribution increased the models′ ability to explain the vegetation productivity variation. The RUE combined with land cover dynamics was valid for the effectiveness assessment of the ecological engineering projects on vegetation restoration. Particularly, the result based on growing season accumulated normalized difference vegetation index(ΣNDVI) residuals was the most effective, showing that 47.39% of the BTSSR experienced vegetation restoration from 2000 to 2010. The effectiveness of the ecological engineering projects differed for each subarea and was proportional to the strength of ecological engineering. The water erosion region dominated by woodland showed the best restoration, followed by the wind-water erosion crisscross regions, while the wind erosion regions dominated by grassland showed the worst effect. Seriously degraded regions still cover more area in the BTSSR than restored regions. Therefore, more future effort should be put in restoring degraded land.  相似文献   

2.
Farmland protection and delimitation in the urban fringe considers not only natural factors but also the spatial characters and site factors. Taking Daxing District, Beijing in China as a case study, this paper used landscape ecology and power-law methods to analyze and evaluate farmland loss during the period of 2004-2007 based on the interpretation results of SPOT5 remote sensing images in 2004 and 2007. At the patch level, we selected four landscape indices, namely patch size, shape index, the nearest neighbor distance between farmland and construction land (including residential land and other construction land), and cropping type, to evaluate the risk of farmland loss and establish a farmland site analysis indicator system. The results showed that patch size and shape index have a significant positive correlation with farmland loss, whereas the distance to construction land has a clear negative correlation with farmland loss. As regards cropping type, fallow farmland is much easier for non-agricultural use than cultivated farmland. The relative transition ratio among vegetable land, fallow farmland and cultivated farmland is 1︰5.6︰1. The patch size of lost farmland follows a power-law distribution, indicating that not only small parcels but also large parcels can be lost. Patch size less than 4 ha or more than 15 ha is in high loss risk, between 4 ha and 10 ha in medium loss risk, and larger than 10 ha and less than 15 ha in low risk. Farmland with a more regular shape has a higher likelihood of loss. Patch shape index less than 2.0 is in high loss risk, between 2.0 and 3.0 in medium loss risk, and larger than 3.0 in low risk. Construction land has a varying impact on farmland loss, the residential land effected distance is 1000 m, and that of the other construction land is 2000 m. This analysis showed the relationships between site factors and farmland loss, and the analysis framework can provide support and reference for farmland protection and delimitation of prime farmland in China.  相似文献   

3.
Mountain ecosystem,on the earth,has plenty of natural resources. In Himachal Pradesh all the rivers are snowfed and therefore rich in water resources. These resources have been supporting enough for the generation of electricity through introducing hydropower projects since the last decade. However,every developmental activity has its own negative impacts on the surrounding environment. Due to the fragile nature of topography and delicacy of ecology of the Himalaya,it results in lot of disturbances because of high degree of human interferences like construction of major hydropower projects. The increased extent of geological hazards,such as landslides,rock fall and soil erosion,have mainly due to alike developmental interventions in the natural ecosystem. So understanding and analysing such impacts of the hydropower projects have mainly been on the environment in various forms but natural hazards have been frequent ones. The present study,therefore,focuses mainly on the Parbati Stage Ⅱ (800 MW) and the Parbati Stage Ⅲ (520 MW) hydropower projects; both of which fall within the Kullu district of Himachal Pradesh. Based on the perception survey of the local communities,the existing land use pattern,status of total acquired land of the residents by hydropower projects,frequent natural hazards and resultant loss to the local communities due to upcoming construction of hydropower projects surrounding to the Parbati Stage Ⅱ and Ⅲ have been analysed in the paper. Also,the preventive measures to mitigate these adverse impacts have been suggested to strengthen these projects in eco-friendly manner in the mountain context.  相似文献   

4.
County-level industrial development and structure upgrade is one of the most important issues of revitalizing old industrial base of China. After the cluster analysis on GDP per capita and GDP per area of each county in Liaoning Province, this paper finds the similarity of population size, land use intensity, and economic development of each county. Location quotient reflects the specialization intensity of industries in each county, and it also reflects the spatial differences of county-level industrial development. Economic development level is higher in the southeast than in the northwest of Liaoning, and the industry driving effect on county-level economy is apparent. The main influencing factors include location, industrial foundation and economic system reform, capital input level, knowledge and technology dissemination, conditions of domestic and overseas markets, population and labor force transfer. Industrialization is an important approach to urbanization for the counties in Liaoning Province. The proportion of agriculture is much higher in the northwest than in the southeast of Liaoning, so it will be take longer time for counties in the northwest of Liaoning to make industrialization, urbanization and modernization.  相似文献   

5.
Slope reinforcement for housing in Three Gorges reservoir area   总被引：1，自引：1，他引：0  
The Three Gorges Project of the Yangtze River is the largest hydropower-complex project under construction in the world. Under the largescale relocation projects, 2874 engineered slopes are formed along with the construction of new towns. In this paper, the cutting slopes are mainly soil slopes and rock slopes. Soil slopes include residual soil slopes, colluvial accumulation slopes, swelling soil slopes, and artificial earth fill slopes, etc. Rock slopes include blocky structure rock slopes, layer structure rock slopes, and clastic structure rock slopes, etc. Varied protection measures have been used for slope protection in the reservoir area including shotcrete concrete-anchor bars, frame beams, retaining walls, slope stabilizing piles, sheet-pile walls, anchorage anti-shear tunnels, flexible protection grids, and drainage, etc. Besides, slope deformation monitoring systems have been set up to monitor deformation failure and the stability state of slopes. The protection measures have guaranteed slope safety and maintained a harmony with the urban environment and surrounding landscape.  相似文献   

6.
Poyang Lake, in Southeastern China and Jiangxi Province,is an ecological treasure of global significance.Scores of endangered species share the lake's productivity with the 10 million people who live on its surrounding shores. Knit together in a  相似文献   

7.
The establishment of nature reserves is a key approach for biodiversity conservation worldwide. However, there is a lack of unified methodology to evaluate the effectiveness of nature reserves, particularly in China, the world′s most populous nation supporting some of the most valuable biodiversity hotspots in the world. In this study, we conducted a long-term and large-scale analysis of the effectiveness of 20 of the earliest nature reserves established in Hainan Province, an island home to among the highest concentration of plants and animals in China. Remote sensing imagery from 1988, 1998, and 2008 were analyzed to investigate the temporal and spatial changes of natural forests in these nature reserves and surrounding areas. We also conducted transition matrix analysis and principle component analysis to identify the driving factors that affect the protection effectiveness of nature reserves. The results were as follows: 1) During the 20-year period from 1988 to 2008, natural forests coverage of the 20 studied nature reserves dropped 2.34 percentage points, whereas the natural forests coverage dropped 11.31 percentage points in a 0–5 km outside reserve buffer and 9.36 percentage points in a 5–10 km outside reserve buffer, indicating a significant inhibitory effect of the nature reserves on the loss of natural forests. 2) Natural forests coverage dropped in 60% of the studied nature reserves during the 20-year period, suggesting a poor protection effectiveness of these reserves, while the coverage proportion showed some increase(0%/yr–5%/yr) in other reserves. 3) Expansion of rubber and pulp forests as part of a booming economy were the main factors affecting the effectiveness of the nature reserves for conserving natural forests in Hainan Province. The results of this study provide an important empirical basis for the protection of natural forests in Hainan Province, which can be used as a blueprint for nature reserve evaluation in other places in China.  相似文献   

8.
With the rapid development of urbanization, a large amount of construction spoil was stockpiled around cities and formed extensive dumps. Construction spoil is one of the main construction and demolition(CD) waste and municipal solid waste(MSW). Once the construction spoil dump becomes unstable, it will bring great risks to the surrounding residents. A catastrophic dump failure occurred on 20 December 2015 in Guangming New Strict, Shenzhen, China. Approximately 2.51×106 m3 of construction waste slid out from the dumpsite, destroying 33 houses and causing total 77 casualties. This paper attempts to analyze the failure probability of the construction spoil dump using Monte Carlo simulation considering the spatial variability of soil properties, and to quantify the dynamic human risk considering the increasing urbanization. Influence of urbanization on the human element at risk is analyzed by referring to multi-temporal remote sensing images. A quantitative human risk assessment model is employed to determine the landslide human risk referring an assessment criteria curve between frequency of number fatalities and number of fatalities(F-N curve). It is found that the societal risk at daytime was 0.078, 0.088, and 1.432 in 2002, 2014, and 2015, respectively. Meanwhile, the societal risk at night was 0.034, 0.037, and 0.611 in 2002, 2014, and 2015, respectively. The quantitative method was benchmarked by the other landfill failure. It implies that the human risk increased with the development of urbanization and its value at daytime was approximately twice as much as at night. The new approach for the human risk assessment provides guidance for modern MSW landfills and highlights the obvious influence of urbanization on the human risk in other areas.  相似文献   

9.
Strengthening the regional tourism cooperation is the requirement of both tourism development and tourist competition drive. On the one hand, resources, products, market and infrastructure in tourism are characteristics of half-public goods, which are the externalities. On the other hand, tourism competition has evolved from individual scenic spot, or finn competition to regional competition, which also requires urgent regional tourism cooperation. In recent years, the regional economic cooperation has been becoming popular in the world. The triangle tourism zone of Liaoning Province, constituted by Shenyang, Dalian and Dandong, is the core region of Liaoning tourism system. This regional tourism cooperation has been raised for a long time, but has not made substantial progress as yet. In recent years, the strategic cooperation among them has been becoming urgent, along with the change of tourism competition models, as well as the desire for building a Northeast Asia tourist economy circle. Based on literature, this paper establishes a conceptual frame of regional tourism cooperation and applies it in the analysis of the strategic tourism cooperation of Liaoning Province＇s golden triangle zone. This paper firstly examines both qualifications and motives concerning with cooperation among the three cities, and believes that the biggest difficulties involve traditional ideas, administrative institutions, communications, economic performances, time constraints, and more overlap among their tourist markets. Then this paper continues to construct a cooperating mechanism, including participant arrangements, construction of operating mechanism and construction of assisting mechanism. At last, this paper proposes approaches to the strategic cooperation such as introducing Xiuyan County, strategic integration and developing differentiated and complemented tourism products.  相似文献   

10.
1INTRODUCTION Albic soil is one of the main soils with low yield in the Sanjiang Plain, with an area of 200×103ha, accounting for 19% of the total area, among which 88.4×103ha is farmland, being 25.4% of the total area of farmland in this region. The albic soil occupies 44% of total area of farmland in the state-owned farms of Heilongjiang Province.Therearetworeasonsforthe lowyield ofalbic soil. Firstly, the upper layer of the soil is thin, only 10- 20cm for low yield field and 20- 25c…  相似文献   

11.
The Caofeidian Reclamation Project has been the biggest reclamation project in China so far, in which 310 km~2 sea areas were reclaimed along the coast of Hebei Province, and it also bring about many problems and defects for large reclaiming area. The study focuses on the influences of the engineering exerted on evolution of the Laolonggou Lagoon with the methods of topographical measurement and surface sediment analysis. The results demonstrate that the topographical changes in the Laolonggou Lagoon had been controlled obviously by the engineering at three stages. Besides, blocking and reopening of the shoal tidal channel also affected the geological environment of the lagoon area. In the aspect of topographical change, the Laolonggou Inlet first experienced deposition after the shoal tidal channel was blocked, followed by short-time eroding for quarrying and cofferdam construction in the east, then depositing slowly after the reclaiming activity ceased, and finally eroding after the shoal tidal channel was reopened. The project, particularly cofferdam construction led to the movement of the Laolonggou Inlet axis from west to east for 50 – 100 m. In the aspect of sediment variation, the reclamation project and hydrodynamic change resulted in the variation in compositions and distribution pattern. The western lagoon area has become land mainly constituted by silt, while the sediments in the eastern area have turned finer in size. After the shoal tidal channel was reopened, the current velocity in the Laolonggou Inlet has been enhanced, making the sediments at the bottom become coarser. The sediments around the Caofeidian foreland went through a process of changing in grain size from fine to coarse and back to fine again, and the sediments are mainly constituted by silt at present.  相似文献   

12.
Some unfavorable geological conditions can affect the construction of tunnels.In order to evaluate the damage degree of tunnel construction and determine the surrounding rock grade and stability of the tunnel,the authors used high-density resistivity method to detect the surrounding rocks of Shimodong tunnel in Xicheng Town of Helong City.The underground resistivity structures of the entrance,exit and middle parts of the tunnel are obtained.Through analysis,it is found that there are no bedrock faults near the tunnel,although some joints and fissures are developed in some locations,which are characterized by low-resistivity anomalies.The tunnel structures are stable overall,favorable for safe and efficient construction.The study also proves the good application effect of the high-density resistivity method in tunnel safety detection.  相似文献   

13.
The Muzhailing extra-long highway tunnel and corresponding inclined shafts in Lanzhou,Gansu Province,China passes through structurally complex carbonaceous slate that is under high ground stress.Rationally-designed and effective support is of high importance for achieving safe and efficient tunnel construction.The No.2 inclined shaft of Muzhailing Tunnel was taken as the engineering background prototype,for which,a similar model test was conducted to evaluate the effect of highly pretightened constant resistance(NPR,Negative Poisson’s Ratio)anchor cable support provision to the geologically complex carbonaceous slate at different depths.Two schemes were proposed during testing:one scheme was without support and the second was with asymmetric support from highly pre-tightened constant resistance anchor cable.Digital speckle displacement analysis system and micro-groundstress sensors were employed to measure the deformation and shear stress distribution of the tunnel.The results demonstrated that through the second support scheme,the deformation of the surrounding rock could be effectively ameliorated,while this support scheme was applied on the project site of the No.2 inclined shaft,to explore the rationality of the scheme through field engineering tests.On-site monitoring indicated that the deformation of the surrounding rock was within the reasonable design range and the problem of severe tunnel deformation was effectively controlled.The research methods and related conclusions can be used as a reference for the treatment of large deformation problems in deep-buried soft rock tunnels.  相似文献   

14.
With the astounding development and gradual improvement of remote sensing technology, as an advancedscience technology, it is used to provide multi-temporal, large scope real-time information for land-use dynamic change,and also is one of the best efficient methods for studying the earth resources and environment. Remote sensing image hasits characteristics of ample information and reflecting the objective realities. The paper uses multi-temporal TM images in1986, 1996 and 2000, and relevant statistic data to analyze land-use changes of Dalian City in Liaoning Province of Chi-na over ten years by means of the correlation analysis method. The results have shown that two methods could con-formably reflect the present land-use change. Urbanization is closely correlative to natural factors and economic develop-ment. Especially in recent 20 years, under the influence of the reform and open-up policy, Dalian, as a specific coastcity, is becoming an international metropolis.  相似文献   

15.
《山地科学学报》2020,17(1):203-215
Changes of cultivated land patterns caused by major water conservation projects are rarely reported. We selected the Three Gorges Reservoir area in China to study the change in area and landscape pattern of the cultivated land in the head,central, and tail areas of the reservoir that took place between 1992 and 2015; we then studied the spatial distribution of the cultivated land in the three parts of the reservoir; finally, we studied the driving forces behind the changes in the cultivated land. The results derived are as follows.(1) During the construction of the Three Gorges Project(TGP, 1992–2015), the area of cultivated land around the reservoir decreased by30.23 million ha. This reduction occurred in phases:the most severe change in cultivated land occurred during the later stage of the project(2002–2010);only 0.62 million ha of cultivated land did not change between 1992 and 2015.(2) Spatial pattern analysis showed that the cultivated land in the three parts of the reservoir changed from a northern distribution to a southern distribution; thus, the area of cultivated land in the north decreased over the time period. The area of cultivated land in the head and tail areas decreased by varying degrees, while it increased in the central area over the 23 years, indicating that the change in cultivated land showed regional differences.(3) The TGP, the policy of reverting farmland to forest,and urbanization were the main driving factors for the change of cultivated land, but there were differences in their impacts at different stages.(4) According to the patch dynamics of the land cover change, the degree of change gradually intensified during the early and later stages of the project and then stabilized during the operational period. Our research provides scientific support for the protection of cultivated land resources and food security in the reservoir area and for the coordination of social and economic development, which is of great significance to sustainable development in the reservoir area.  相似文献   

16.
In this paper,spatial correlation of crop yield in the middle and west of Jilin province is analyzed by us-ing the method of geostatistics swmivarivogram,taking the NDVI of NOAA/AVHRR spectrum data as the regionalized vari-able,aiming to provide theory and practical basis for field sampling of crop yield estimation using remote sensing.The ratio of nugget variance and sill of semivariograms are 21.1% and9.7% in the west and middle regions in Jilin Province respectively.This shows that the crop yields are spatially correlated.The degree and range of correlation are far different in the different situations.In the west test region,the range is 49.9km and the sill is 0.00019 .In the middle test re-gion,the range is 16.5km and the sill is 0.00453.The dissimilarity in the western test region is larger than that in the middle one.The range in which the correlation existed of the former is far larger than the later.Different characteristics of spatial correlation of crop yield are decided by the environmental factors.Samples for crop yield estimation should be extracted according to the characteristic of spatial distribution of crop yield to promote the efficiency of sampling.  相似文献   

17.
Based on remote sensing technique,using 1990’s Landsat TM data and 2000’s Landsat ETM data,the authors conducts the comparative study of mainstream area of Songhua River by means of human-computer inter-action method.The results show that the area of Songhua River mainstream was 738 102 km 2 in 1990,and was 810.451 km 2 in 2000.From 1990 to 2000,the increased area of river mainstream is up to 72.349 km2 due to soil erosion and water loss.Meanwhile,the dynamic changes of surrounding vegetation cover are also studied.It is estimated that the trend of surrounding soil erosion and water loss of Songhua River mainstream becomes worse in Jilin Province.  相似文献   

18.
Non-point source （NPS） pollution has become a major source of water pollution. A combination of models would provide the necessary direction and approaches designed to control NPS pollution through land use planning. In this study, NPS pollution load was simulated in urban planning, historic trends and ecological protection land use scenarios based on the Conversion of Land Use and its Effect at Small regional extent （CLUE-S） and Soil and Water Assessment Tool （SWAT） models applied to Hunhe-Taizi River Watershed, Liaoning Province, China. Total nitrogen （TN） and total phosphorus （TP） were chosen as NPS pollution indices. The results of models validation showed that CLUE-S and SWAT models were suitable in the study area. NPS pollution mainly came from dry farmland, paddy, rural and urban areas. The spatial distribution of TN and TP exhibited the same trend in 57 sub-catchments. The TN and TP had the highest NPS pollution load in the western and central plains, which concentrated the urban area and farm land. The NPS pollution load would increase in the urban planning and historic trends scenarios, and would be even higher in the urban planning scenario. How- ever, the NPS pollution load decreased in the ecological protection scenario. The differences observed in the three scenarios indicated that land use had a degree of impact on NPS pollution, which showed that scientific and ecologically sound construction could effec- tively reduce the NPS pollution load in a watershed. This study provides a scientific method for conducting NPS pollution research at the watershed scale, a scientific basis for non-point source pollution control, and a reference for related policy making.  相似文献   

19.
This study used spatial autoregression（SAR） model and geographically weighted regression（GWR） model to model the spatial patterns of farmland density and its temporal change in Gucheng County,Hubei Province,China in 1999 and 2009,and discussed the difference between global and local spatial autocorrelations in terms of spatial heterogeneity and non-stationarity. Results showed that strong spatial positive correlations existed in the spatial distributions of farmland density,its temporal change and the driving factors,and the coefficients of spatial autocorrelations decreased as the spatial lag distance increased. SAR models revealed the global spatial relations between dependent and independent variables,while the GWR model showed the spatially varying fitting degree and local weighting coefficients of driving factors and farmland indices（i.e.,farmland density and temporal change）. The GWR model has smooth process when constructing the farmland spatial model. The coefficients of GWR model can show the accurate influence degrees of different driving factors on the farmland at different geographical locations. The performance indices of GWR model showed that GWR model produced more accurate simulation results than other models at different times,and the improvement precision of GWR model was obvious. The global and local farmland models used in this study showed different characteristics in the spatial distributions of farmland indices at different scales,which may provide the theoretical basis for farmland protection from the influence of different driving factors.  相似文献   

20.
The Grain for Green Project(GGP) is an important measure for the prevention of sloping farmland and the restoration of natural vegetation.This project has been critical to the restoration of ecological environments in western China. However,the effect of the GGP on freshwater ecosystem services under extreme climates remains unclear. Thus, taking the middle and upper reaches of the Wujiang River Basin in western China as an example, this study assessed the variation of three freshwater ecosystem...  相似文献   

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