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Distribution and division of sensitivity to water-caused soil loss in China
... 3.1.3 Assessment of water-caused soil loss sensitivity Having considered the formation mechanism and having referred to previous studies (Yoder and Lown, 1995;Wang et al., 2001;Liu et al., 2003;Pan and Dong, 2006;Pan and Feng, 2010;Pan et al., 2012;Pradhan et al., 2012;Pan and Wen, 2014;Liu et al., 2015), we assessed water-caused soil loss sensitivity using four main factors: relief, vegetation coverage, rainfall erosivity and soil erodibility. The slope gradient and slope length were difficult to calculate on a (Wang et al., 2001). ...
... Assessment of water-caused soil loss sensitivity Having considered the formation mechanism and having referred to previous studies (Yoder and Lown, 1995;Wang et al., 2001;Liu et al., 2003;Pan and Dong, 2006;Pan and Feng, 2010;Pan et al., 2012;Pradhan et al., 2012;Pan and Wen, 2014;Liu et al., 2015), we assessed water-caused soil loss sensitivity using four main factors: relief, vegetation coverage, rainfall erosivity and soil erodibility. The slope gradient and slope length were difficult to calculate on a (Wang et al., 2001). Water-caused soil loss is more likely to occur in the region with less vegetation coverage. ...
... Soil erodibility was calculated as reported in a previous study by comprehensively considering the content of sand, silt, and clay grain, as well as organic carbon (Yu et al., 2014). Table 1 presents the grading standard or method for this issue (Wang et al., 2001;Liu et al., 2003;Pan and Dong, 2006;Pan et al., 2012;Liu et al., 2015). Subsequently, the sensitivity index was calculated by the weighted mean method, using the grading layers of these indicators. ...
... On the other hand, taking into account the regional characteristics of soil erosion, there is an emphasis on macro-level expression of results and conducting nationwide regional distribution studies [23][24][25]. The main outcomes include soil erosion zoning, distribution Water 2024, 16, 3434 3 of 20 of erosion types, and national surveys on erosion status [26][27][28][29]. In recent years, China has conducted three nationwide soil erosion surveys. ...
Soil erosion has become an increasingly serious issue, drawing global attention. As one of the countries facing severe soil erosion in the world, China confronts significant ecological challenges. Against this backdrop, the country places great emphasis on soil conservation efforts, considering them a crucial component of ecological civilization construction. This study focuses on the carbon sink benefits of comprehensive soil conservation management in the loess hilly region and sandy slopes, using the Xiaonanshan Mountain small watershed in Youyu County, Shanxi Province, as a typical case for in-depth analysis. In terms of research methodology, an integrated monitoring approach combining fundamental data, measured data, and remote sensing data was developed. A comprehensive survey of the Xiaonanshan Mountain small watershed was conducted to categorize plant carbon pools and soil carbon pools, establish baseline scenarios, and utilize methods such as inverse distance spatial interpolation, sample calculation, and feature extraction to estimate forest carbon storage across different years and determine changes in soil and vegetation carbon storage. Simultaneously, data collection and preprocessing were carried out, including the gathering of fundamental data, field data collection, and internal data preprocessing. On this basis, a vegetation carbon storage model was constructed, and an assessment of soil carbon pool storage was conducted. The research results indicate that from 2002 to 2024, the continuous implementation of various soil conservation measures over 22 years has led to a significant increase in carbon storage within the Xiaonanshan Mountain small watershed. The vegetation carbon density of the entire small watershed increased from 14.66 t C/ha to 27.02 t C/ha, and the soil carbon density rose from 28.92 t C/ha to 32.48 t C/ha. The net carbon sink amount was 18,422.20 t C (corresponding to 67,548.08 t CO2e in terms of carbon dioxide equivalent). Populus simonii and Pinus sylvestris var. mongholica significantly contribute to the carbon sink; however, due to partial degradation of Populus simonii, its net carbon sink amount is less than that of Pinus sylvestris var. mongholica. Additionally, the carbon sink capacity of the small watershed exhibits spatial differences influenced by conservation measures, with high carbon density areas primarily concentrated within the range of Populus simonii, while low carbon density areas are mainly found in shrub zones. The increase in carbon storage within the small watershed is primarily attributed to the contributions of vegetation and soil carbon storage, indicating that comprehensive soil erosion management has a significant carbon accumulation effect; moreover, the annual growth rate of vegetation carbon storage exceeds that of soil carbon storage, with the proportion of soil carbon storage increasing year by year. Furthermore, the vegetation carbon sink, soil carbon sink, and total carbon sink of the small watershed were separately calculated. In terms of benefit analysis, the Xiaonanshan Mountain small watershed offers ecological benefits such as increased forest coverage, carbon fixation and oxygen release, and biodiversity conservation; from an economic perspective, the value of carbon trading is substantial, promoting soil conservation and rural revitalization, with the total value of timber reaching 7.6 million yuan, of which the value of standing timber constitutes the largest proportion; social benefits include the improvement of environmental landscapes, stimulation of ecological tourism, and attraction of investment, with the Xiaonanshan Mountain Ecological Park receiving numerous visitors and generating significant tourism revenue. This research provides a theoretical basis and data foundation for comprehensive soil conservation management in project areas or small watersheds within the loess hilly and sandy slope regions, offering technical and methodological support for other soil conservation carbon sink projects in the area.
... With the advancement of technology and the surge of population, the demand for resources and expansion of urbanization are exploding, gradually exceeding the limits of the ecosystem, leading to a severe dichotomy between ecosystem maintenance and human development. Different types of ecological and environmental problems, including the greenhouse effect (Gao et al., 2003), atmospheric pollution (Li et al., 2012a) and soil erosion (Wang et al., 2001), have emerged obviously at a global scale. ...
... Ecological sensitivity refers to the sensitivity of an ecosystem to sudden environmental changes and human activities, which indicates the possibility of an ecological imbalance [41]. It is closely related to ecological protection and the restoration of mountain-river-forestfarmland-lake-grass. ...
The Minjiang River Basin is one of the first pilot areas for ecological conservation and the restoration of mountain–river–forest–farmland–lake–grass in China. Taking the Minjiang River Basin as an example, this paper selected the importance of ecosystem service functions and ecological sensitivity to evaluate the ecological environment and identify ecological sources. Furthermore, we constructed an ecological resistance surface using artificial and natural interference factors. Through a minimum cumulative resistance model (MCR), the ecological security pattern (ESP) of “two barriers, one belt, many corridors, and many spots” was constructed. Research shows that: (1) In total, 43 ecological sources were identified, with a total area of 523 km2, accounting for 0.6% of the total land area. These were mainly distributed in the southwest and northwest of the Minjiang River Basin, such as in Zhangping, covered forest land, and cultivated land. (2) The connectivity of the network was low, and the spatial distribution of the ecological pinch points was uneven. A total of 118 ecological corridors and 22 important ecological pinch points were identified. The total length of the ecological corridor is 3,732,051.88 km, which is dense on the left side and sparse on the right side. (3) The ecological restoration area was composed of a low ecological safety area and a lower ecological safety area; the ecological control area was composed of a medium ecological safety area and a higher ecological safety area; and the ecological conservation area was composed of a high ecological safety area, at 6.5%, 27.7%, and 65.8%, respectively. Constructing the ESP of the Minjiang River Basin is important for promoting harmonious socioeconomic development and ecological protection. In addition, it can provide a reference basis for other experimental areas of mountain–river–forest–farmland–lake–grass.
... The BTH has a continental monsoon climate, with concentrated precipitation and heavy rain, and diverse geomorphic types. Due to the deterioration of natural environment and unreasonable human development, the Yanshan-Taihang Mountain region has become one of the most prominent soil and water loss in China (Wang et al., 2001;Wang et al., 2014); The soil and water loss in Miyun Reservoir and Chaohe River Basin is also becoming serious (Pang et al., 2007;Jiang and Wu, 2013). The negative impact of rapid urbanization on ecosystem is another challenge in BTH, and forest protection will be an effective strategy for planning urban landscape to maintain key ecosystems (Wu, et al., 2021). ...
Understanding the dynamic change and interrelations among multiple ecosystem services (ESs) is crucial for the sustainable development of economy and nature, especially in Beijing-Tianjin-Hebei (BTH) urban agglomeration, which is an important capital economic circle and ecological barrier in northern China. In BTH, the spatio-temporal analyses of ESs dynamics were quantified using different models, and their interrelations (i.e., trade-offs and synergies) were analyzed using the partial correlation analysis at the pixel scale. Further, a Multiple Ecosystem Services Landscape Index (MESLI) was built to discuss the integrated capacity and efficiency of ESs. The results were as follows: (1) The inter-annual variation of MESLI was significantly different in each ecological regions. The MESLI of Bashang Plateau (R-A) and Yanshan-Taihang Mountains (R-B) showed increasing trend, while decreased in Beijing-Tianjin-Xiongan Urban Agglomeration (R-C) and the agricultural region of North China Plain (R-D). Both net primary production and water conservation increased during 2000–2015, while habitat quality declined linearly, but promoted to 0.60 during 2016–2018. (2) The MESLI and single ES were high in R-B due to the high vegetation coverage, which benefited from continuous ecological engineering in this region. The low above indexes in R-C and R-D was attributed to the destruction of natural ecosystem caused by agricultural development and urban sprawl. (3) The spatial synergies among ESs were normally well in the northern Yanshan Mountain, while the trade-offs were obvious in the southern Hebei Plain, and the relationship of trade-offs and synergies among ESs in Bashang Plateaus and Beijing-Tianjin-Xiongan urban agglomeration demonstrated uniform distribution. The spatial correlation and differentiation should be considered in policy-making of regional ecosystem management.
... Soil erosion is the serious damage to natural resources of water, soil and land productivity [49].The soil erosion sensitivity result was calculated by formula (2), as shown in Table 5 and Figure 4a. It shows a lower sensitivity at both ends and a higher sensitivity in the middle. ...
In recent years, ecosystem service values (ESV) have attracted much attention. However, studies that use ecological sensitivity methods as a basis for predicting future urban expansion and thus analyzing spatial-temporal change of ESV are scarce in the region. In this study, we used the CA-Markov model to predict the 2030 urban expansion under ecological sensitivity in the Three Gorges reservoir area based on multi-source data, estimations of ESV from 2000 to 2018 and predictions of ESV losses from 2018 to 2030. Research results: (i) In the concept of green development, the ecological sensitive zone has been identified in Three Gorges reservoir area; it accounts for about 35.86% of the study area. (ii) It is predicted that the 2030 urban land will reach 211,412.51 ha by overlaying the ecological sensitive zone. (iii) The total ESV of Three Gorges Reservoir area showed an increasing trend from 2000 to 2018 with growth values of about USD 3644.26 million, but the ESVs of 16 districts were decreasing, with Dadukou and Jiangbei having the highest reductions. (iv) New urban land increases by 80,026.02 ha from 2018 to 2030. The overall ESV losses are about USD 268.75 million. Jiulongpo, Banan and Shapingba had the highest ESV losses.
... Studies have shown that the implementation of the GFG has promoted ecosystem services in relevant areas, such as an increase in vegetation coverage (Xiao, 2014), a decrease in soil erosion (Lü et al., 2012), a raised carbon sink , and enhanced per-unit yield of cultivated land . In the Loess Plateau, the most important ecosystem function the GFG aimed at was control soil erosion, which was the most prominent ecological problem in the area (Qiu, Fu, & Wang, 2002;Wang, Ouyang, Xiao, Miao, & Fu, 2001;Zhang, Zhang, Yang, & Zhu, 2019). From 1955to 1989.6% of the Loess Plateau had an average annual soil loss of 2,500 t km −2 , which was considered to be a moderate erosion level (Wang & Jiao, 2002). ...
Although it is generally believed the Grain for Green (GFG) implemented in China has attenuated soil erosion, whether it is effective still needs verification. Taking Yan'an in the Loess Plateau as the study area, we analyzed both total effect and efficiency differences during the GFG implementation. Results showed while the average soil erosion decreased from 4884.49 t·km‐2·a‐1 to 4087.57 t·km‐2·a‐1, counties with higher GFG implementation intensity unachieved larger soil conservation effect. For example, Wuqi ranks 3rd in the GFG implementation intensity among all counties in Yan'an, but its real soil erosion reduction is the lowest, only 54.1% of Yan'an's average level. To analyze the reason for the efficiency difference, the concept of soil conservation potential was proposed. It is concluded that the soil conservation effect is controlled by the soil conservation potential. Ideally, regions with high soil conservation potential should get priority in the GFG application, yet there is a significant spatial mismatch between the GFG implementation intensity and the soil conservation potential since the correlation coefficient is only −0.05, which weakened the soil control effect. On the base, a dynamic implementation mechanism was put forward for the formulation and optimization of ecological projects in future. Firstly, using the soil conservation potential to determine the implementation intensity in each region; secondly, adjusting the intensity to the changes of the soil conservation potential in the following implementation; at last, repeating above steps to ensure high efficiency of soil erosion control, and achieving the sustainability and effectiveness of the ecological projects.
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... Considering the validity of the data based on the existing research (Wang et al. 2001(Wang et al. , 2014a, the susceptibility of soil erosion is based on the influence of climate, soil properties, topography, and surface coverage. For the soil loss type due to water erosion in the study area, rainfall, landform, soil type and land use, were determined as indicators for soil erosion susceptibility assessment. ...
It is of great significance to conduct an assessment of the susceptibility of certain area to geo-environmental hazards that are intended land-use planning, for hazard prevention. This study first evaluated the four geo-environmental hazards susceptibility in Luoning County using the Analytic Hierarchy Process (AHP). Then, Barrel Principle was used to render a comprehensive hazard susceptibility map, reflecting the stability level of the regional geo-environment. Results showed that the geo-environmental hazards susceptibility area can be graded into four levels, including high-susceptibility, moderate-susceptibility, low-susceptibility, and stable, accounting for 25.3%, 44.8%, 26.5%, and 3.4% of the study area, respectively. Success rate curve was applied to validate the accuracy of the single-hazard susceptibility map produced using the AHP. The results showed that the landslide, rockfall, and goaf collapse susceptibility maps had a success rate of 83.28%, 77.07%, and 85.19%, respectively. Therefore, the single susceptibility map can be helpful for hazard assessment and land-use planning. Finally, a comprehensive susceptibility map was used to select areas of priority for urban development and prevent and mitigate natural hazards that occur.
... The vegetation cover factor (C) is sensitive to natural and anthropogenic activities and is critical to soil and water conservation (Wang et al., 2001). The value of C directly affects the value of soil loss and SDR. ...
... At the same time, it also can influence the social and economic sustainable development of China. To some extent, it is becoming the main ecological environmental problems (Wang et al., 2001). There are many reasons for water loss and soil erosion. ...
Global sensitivity analysis of the parameters of the modified universal soil loss equation (MUSLE) was conducted by using the extended Fourier amplitude sensitivity test (EFAST) method. Results show that the runoff factor, slope length and gradient factor, crop management factor and erosion control practice factor were the most sensitive parameters which affected the model outputs, followed by soil texture, organic matter content, aggregation class and the class of the water permeability of the soil profile. The number of iterations for Monte Carlo simulation had significant influence on the sensitivity analysis results. Only when the number of iterations was larger than 50000, EFAST can yield satisfactory convergence of sensitivity indices. Overall, the interaction of the runoff factor, soil erodible factor and adjustment factors was substantial when using the MUSLE. The key parameters should be prioritized for calibration to determine the most optimal values and reduce the uncertainty in soil loss predictions.
... Vegetation plays a significant part in controlling soil erosion (Collins et al., 2004;Zhou et al., 2006). The vegetation cover factor is critical to soil and water conservation, owing to its high sensitivity to natural and anthropogenic activities (Wang et al., 2001;Ma et al., 2012). Here, the value of the C factor was primarily obtained by referring to previous studies, with a smaller value linking to better controlling effect. ...
Ecological sensitivity analysis is an important basis for urban planning and layout. This article selects six ecological evaluation factors, including altitude, slope, aspect, water environment, vegetation NDVI, and land use, to construct an ecological sensitivity evaluation system for Xinyi City. Using the spatial analysis techniques of GIS and the Analytic Hierarchy Process (AHP), a comprehensive evaluation was conducted on six ecological evaluation factors. Meanwhile, the natural breakpoint method was used to divide the results into five levels: extremely sensitive area, high sensitive area, medium sensitive area, low sensitive area, and non-sensitive area. The results indicate that the ecological sensitivity of Xinyi City is generally high, and land use type, vegetation coverage, and water environment are the main factors affecting ecological sensitivity. The five sensitive areas, from non-sensitive to extremely sensitive, account for 0.71%, 18.44%, 38.88%, 33.01%, and 8.96% of the total area of the city, respectively. The highly sensitive areas of Xinyi City are distributed in the northeast, while the non-sensitive areas are distributed in the southwest. The comprehensive evaluation of ecological sensitivity and spatial layout in this article can provide a basis for land use construction planning and ecological environment protection in Xinyi City.
The Loess Plateau of China suffers from severe erosion, which results in a great variety of economic and ecological problems. For scientific control of soil erosion, the key questions urgently to be addressed in this paper are: (1) Which are the driving factors under diverse geomorphological types? (2) Do these driving factors operate independently or by interacting? (3) Which zones under diverse geomorphological types suffer from severe erosion and need more attention? In this paper, the RUSLE model was applied here to demonstrate the spatio-temporal variations in soil erosion from 2010 to 2017 in Yan’an City, and the Geo-detector model proved to be a useful tool to solve the questions mentioned above. The results showed that the average erosion modulus in Yan’an City decreased by 1927.36 t/km2·a from 2010 to 2017. The intensity of soil erosion in the northern Baota District, central Ganquan County, Luochuan County, Ansai County, and Zhidan County decreased to varying degrees. The effect size of driving factors affecting soil erosion varied significantly in diverse geomorphological types. The effect size of interaction between land-use types and vegetation coverage, land-use types and slope, slope and precipitation was higher than that of a single factor. High-risk zones with severe erosion were closer to cultivated land and forest land with steep slopes (>25°) in the mid-elevation hills of Yan’an City. Additionally, based on the specificity of the study area, the Geo-detector model performed better in a relatively flat region, and factors with macroscopic spatial distributions weaken its explanatory power on soil erosion on a regional scale. Based on data selection, data of different accuracy sparked the issue of “data coupling”, which led to the enormous deviation of model results in mid-elevation plains. Results from our analysis provide insights for a more ecologically sound development of Yan’an City and provide references for the scientific use of the Geo-detector model.
Groundwater systems are an important part of the world's ecosystems, linking the lithosphere, atmosphere, hydrosphere, and biosphere. Groundwater is the dominant factor influencing vegetative community distribution patterns in the arid and semi-arid regions of Northwest China. Also, groundwater is the primary source of water for human uses in North China. With recent economic growth, the region is experiencing rapid development of its groundwater resources. The groundwater has been and is being seriously depleted and the system is displaying some unstable characteristics and vulnerabilities, which are significantly impacting the ecology of the area. Various types of sensitivity assessment are often used to study the stability of a region's environment and ecology. A groundwater ecological sensitivity assessment can be used to facilitate protection of the environment and to encourage sustainable development of groundwater resources. This paper provides a case study of the Lower Liaohe River Alluvial Plain, which is in the most economically developed region of Liaoning Province. The area is experiencing a significant water shortage. First, groundwater ecological sensitivity and its attributes were defined. Twenty-two factors were selected to be used in constructing the assessment indicator system. These were based on five aspects of groundwater quality and quantity including: 1) characteristics of the local groundwater system, 2) natural conditions in the region, 3) external pressures including human-caused pressures, 4) resources available and conservation, and 5) the local ecological environment. These factors were designed based on actual conditions of the area studied and took into account a variety of indicators including spatial scale, dominating environmental conditions, independence from other factors, sensitivity of the local groundwater resources to impacts, early warning signs of problems within the groundwater system, the cumulative impact of qualitative and quantitative factors, practicality of use factors, a need to standardize the data, and classification of various factors and impacts on ground water resources. Each factor was defined and described. The sensitivity of groundwater in relation to each factor was ranked on a scale of one to five, defined as 1) insensitive, 2) slightly sensitive, 3) moderately sensitive, 4) highly sensitive, and 5) extremely sensitive groundwater conditions. The assigned value for each indictor was determined by reviewing related standards and references. Once the various indicators or factors were defined and standardized, a groundwater ecological sensitivity assessment in the Lower Liaohe River Alluvial Plain was carried out. First, the sensitivity of the five aspects of groundwater quality and quantity were evaluated individually by applying spatial analysis of a geographic information system and the distribution of the five factors listed above was analyzed. Second, an integrated sensitivity value was calculated using a weighted model from GIS for water quantity and water quality. For water quantity, the results show the slightly and moderately sensitive areas of water quantity dominate and comprise 65. 14% of the study area. The entire study area was classified as 5. 35% insensitive to water quantity issues, 40. 53% slightly sensitive, 24. 61% moderately sensitive, 21. 64% very sensitive, and 7. 87% extremely sensitive. For water quality, moderately and highly sensitive areas of water quality dominate and compose 86. 56% of the study area. The entire study area was classified as 1. 11% insensitive to water quality issues, 10. 99% slightly sensitive, 50. 17% moderately sensitive, 36. 39% very sensitive, and, 1. 34% extremely sensitive. When sensitivity to both water quantity and water quality issues are considered, areas of moderate or higher sensitivity for both quantity and quality occupy more than 59. 62% of the entire research area, indicating the degree of ecological sensitivity is generally high and groundwater resources are very vulnerable. The analysis oh the spatial distribution of the five zones shows the insensitive and slightly sensitive zones are mainly distributed in the Xinmin-Liaozhong plain of the eastern alluvial floodplain. Moderately sensitive zones are mainly distributed in the middle plain and western low mountain region. The highly and extremely sensitive zones are mainly distributed in cities of Liaoyang and Fushun, and in the mountains surrounding the plain.
Irrational land use is the main cause of severe soil erosion on the Loess Plateau of China. Vegetation and rainfall intensity are two important indexes for soil erosion processes. After the "Grain for Green" project was implemented, vegetation recovery has the great significance in reducing runoff and sediment. The purposes of this paper are to discuss the relationship during the rainfall intensity, runoff and sediment yields of bare land, grassland and shrub land under natural rainfall, and determine the differences of runoff and sediment yields of different stages of vegetation restoration on the Loess Plateau. Three runoff plots were set up for the bare land, abandoned grassland and shrub land in the hilly and gully area of the Loess Plateau to probe into relationship between the rainfall intensity, runoff and sediment yields, as well as runoff and sediment reduction differences in different stages of vegetation restoration under natural rainfall condition. Results showed that compared with the grassland and shrub land, runoff and sediment yields from the bare land tended to increase significantly with increased rainfall intensity. The runoff yield from the grassland increased more than that from shrub land as the rainfall intensity increased. The sediment yield increments for the grassland and shrub land resulted from the shift of rainfall types appeared to be rather closer. Heavy rain and rainstorm are the main precipitation forms inducing severe soil erosion on Loess Plateau. Severe soil erosion can be induced if slope does not have sufficient vegetation coverage. Compared with the bare land, the runoff yields from the grassland and shrub land were reduced by 41.7% and 70.4% and the sediment yield by 94.5% and 97.7%, respectively. The runoff reduction benefit on the shrub land was better than that on the grassland, whereas the grassland had the same soil-conserving effect as the shrub land.
Karst regions are typically geologically constrained and ecologically fragile. Karst landscapes can be greatly affected by external factors such as environmental change. Southwestern China has one of the largest karst regions in the world which extends over about 540000 km2 and is home to more than 220 million people. Desertification of the karst environment in this region has expanded at an increasing rate over the last few decades. Water and soil loss processes, and in particular the spatial distribution patterns of water and soil loss, in the karst regions of southwest China are particularly unique. This is due to the solubility of the carbonate rocks that results in a low rate of soil formation, a low-tolerance for soil loss, high topographic relief and the destruction of vegetation. In this study, rainfall erosion, topographic relief, soil types, vegetation types, and soil loss tolerance were selected as indicators used to assess water and soil loss sensitivity. Using GIS techniques, we evaluated the water and soil loss sensitivity of each individual indicator then integrated the results to examine the differences in the spatial distribution of water and soil loss in southwestern China. The results show that rainfall erosion, topographic relief, soil types, and soil loss tolerance are highly sensitive to water and soil loss in karst regions, whereas vegetation cover is not as sensitive. Water and soil loss sensitivity in the karst regions of southwest China is generally high, with more than 82. 76% of the karst regions classified as being at least moderately affected and only 6. 4% of the area classified as insensitive. The spatial distribution analysis indicated that karst regions with moderate of higher deteriorative water and soil loss sensitivity are mainly distributed in northeastern and southeastern Chongqing, southwestern Hubei, northwestern Hunan, most of Guizhou, northeastern Yunnan, and the peak-cluster depression of Guangxi. In addition, as the content of insoluble acidic material in the soils increased, the areas with extreme or high sensitivity to water and soil loss declined, but those with moderate sensitivity to water and soil loss increased. In addition to usual factors such as precipitation, terrain conditions, soil cover, and vegetation, the distribution of ground water and soil loss in karst regions is significantly related to soil loss tolerance. As a result, soil loss tolerance must be considered as an important indicator of water and soil loss in karst regions. However, when the water and soil loss reaches extreme levels, exposed bedrock can become widely distributed. In this situation, there is no water or soil to lose and karst rock desertification occurs. Our results suggest that increases in the extent of karst rock desertification can be taken as a primary indicator of water and soil loss in this region. Therefore, occurrences and changes in karst rock desertification should be taken further into consideration to enhance regional prevention and remediation plans directed at water and soil loss and karst rock desertification. Our study provides useful references for the prevention and control of water and soil loss and the ecological restoration and reconstruction of degraded karst system in southwestern China.
Soil conservation service, as one of the most important regulating services provided by ecosystems, guarantees the ecological security and sustainable development of a region. We quantified the soil conservation service of ecosystems in Hainan Island using the InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs) tool, so as to have a knowledge of its spatial characteristics and impact factors, which could be used for its preservation and ecosystem management then. Our results showed that, the amount of soil preserved by ecosystems of Hainan Island was approximately 8. 16×108 t, and the average capacity per unit area was 247. 28 t·hm-·2 a-1 for the entire region. With regard to the spatial pattern, the central part displayed a much higher capacity than surrounding areas in general, which could be confirmed from the comparison of soil conservation capacity between inside and outside of Mountainous Area of Central Hainan National Ecological Function Conservation Area(NEFCA). Consequently, this NEFCA could be considered to be making a great contribution in preserving soil conservation service in Hainan Island. We also found that, the soil conservation capacity differed widely across various ecosystems, with a descending order from shrubs, natural forests, to grasslands, rubber plantations, pulp forests, tropical plantations, paddy lands, dry lands, mangroves, and shelterbelts. Natural ecosystems were generally found to perform better than artificial ones in terms of conserving soil resource. Besides natural factors, economic development, population explosion and farmland expansion are important factors influencing soil conservation service. Indicators such as gross regional product per area, GDP of primary industry per area, population density and area ratio of farmland, showed a negative relationship with soil conservation capacity(P <0. 05), while area ratio of rubber plantation showed a positive relationship with soil erosion rate (P<0. 01). In conclusion: (1) the central mountainous area was so important for erosion control and ecological security maintenance in Hainan Island, that it should be protected carefully; (2) natural forests performed much better than rubber plantations and dry lands in soil conservation, although their economic benefits went the opposite way. Ignorance of ecological benefits ought to be prohibited and preservation of natural forests should be strictly and continuously implemented; (3) traditional agriculture should be transformed to intensive one, so as to increase both productivity and ecological benefits of farmlands; (4) the economic development and population explosion in Hainan Island might impair soil conservation service of ecosystems, as a result, tradeoffs should be made to realize sustainable development.
Regional ecological sensitivity analysis is an effective tool for making regional environmental policies and environmental management. Literature review indicates that more physical-driving factors than human-driving factors are considered in ecological sensitivity assessment. Our future environment will he consisted largely of human-dominated ecosystems; human activities and anthropogenic impacts are especially important in environmental research. In order to integrate both physical and human driving factors, 7 indices, such as water-caused soil erosion, water quantity and quality of rivers, land sandification, debris flow, mining, road density, and the habitats of endangered species, are selected for ecological sensitivity assessment. Using GIS and RS techniques, the author analyzes the ecological sensitivity degrees and their spatial distributions in Beijing. The results show that high ecological sensitivity regions have two types; one is located in the transition-belt from northeastern to southwestern Beijing, which is between plain and mountain regions in Beijing; the other is distributed along the riparian zones of Yongding River, Chaobai River, North Canal, and Dashi River; and the southern parts of Daxing are also included. Moderate-ecological sensitive regions are distributed around the high sensitive regions peripherally and also distributed in mountainous regions of Hongluo, Yunmeng and Miaofeng. None ecological sensitive regions are largely distributed among the northern mountainous regions of Huairou and Yanqing Others are low ecological sensitive regions. Results also show that (1) the ecological sensitivity degrees decrease from the mountain-plain transition-belt to lower and higher mountainous regions along the northwest direction in mountainous region and, ( 2 ) decreases from the watercourses to riparian zones along lateral direction in plain. Based on these research results, some environmental conservative strategies are suggested for future ecological management.
Ecological function regionalization is a kind of geographic spatial division, which is based on the distribution of ecosystem stress and effect, ecological sensitivity and ecological service importance. The target of ecological function regionalization is to distinguish the regional ecological problems and ecological fragile areas, determine the prior protection ecosystems and regions, and to supply scientific basis for regional ecological protection, region-based ecosystem management and sustainable development. Taken Anhui Province as a case, regional ecosystem sensitivity and service importance assessment were carried out according to the established guidelines. The primary eco-environmental problems and their driving forces of study target were also extracted. With the help of GIS, the spatial distribution of ecosystem sensitivity and service importance were characterized. Based on the above assessment, the provincial ecological function regionalization was worked out, and the ecological protection and construction emphasis, target and measures of each ecological region were also recommended. It indicated that, with the stress of population and economic growth, the eco-environmental quality of Anhui Province is going worse, with the appearance of intensive utilization and lack of cultivated land, strong dependence of agricultural production on external input, resource deficit and function decline of forest ecosystem, diminution and threat of biodiversity, shrinking of wetland, heavy pollution of surface water, capability decrease of anti-disturbance and aggravation of ecological disasters. The extremely sensitive area takes 5. 3% of the total provincial area, with distribution in the southern Wannan Mountain area, Huangshan and Jiuhuashan Mountain, northwestern and southeastern Dabie Mountain area. The highly sensitive area takes 19. 3%, with distribution in Wannan and Dabie Mountain area. The sensitive area takes 36. 8%, with distribution in the Huaibei Plain and hills. The slightly sensitive area takes 38. 6% of the provincial area, with distribution in the Jianghuai Upland and Flatland area, Yangtze-River Plain area and mountain basin area. The most ecologically important area takes 4. 8% of the provincial area, with distribution in the Wannan and Dabie Mountain area, Hill area along Yangtze-river, flood adjustment-store area of Huaihe River. The important-level area takes 21. 5%, with distribution in outer belt area of mountain area, Jianghuai Upland and Flatland area, Huaibei hills. The relatively important area takes 73. 7% of the provincial area, with distribution in the Huaibei Plain, Jianghuai Upland and Flatland area, Yangtze-river Plain area and mountain valley area. Based on the ecosystem assessment, five ecoregions, 16 sub-ecoregions and 47 eco-functional zones were subdivided by the method of "top-down" and with the support of GIS technology. The five eco-regions are: Huaibei Plain Eco-region, Jianghuai Upland and Flatland Eco-region, Wanxi Dabie Mountain Eco-region, Yangtze-river Plain Belt Eco-region and Wannan Mountain and Hill Eco-region. The application of the regionalization result was also discussed in this paper, which focus on the key area screening of ecological protection and construction, the encouraging and restricting profiles of regional development.
The coastal zone is considered as the most dynamic natural environment' providing goods and services essential to human beings. Due to diverse natural and human pressures, many coastal cities are experiencing severe environmental problems such as climate change, sea level rise, coastal erosion, environmental pollution and so on. Land use change is the apparent and widespread consequences of urbanization and global environment changes, which has important impacts on coastal zones, such as directly altering geomorphological configurations, influencing ecosystems and ecosystem services provision, and increasing coastal city's vulnerability. The presence of a perturbation or stress, sensitivity of the affected entity and the system's capacity to cope or respond (resilience) are major elements in the vulnerability analysis of a social-economic-natural complex ecosystem. Sensitivity in this sense is defined as the interaction within the system, between the systems or inside the complex ecosystem used to characterize the response level the system according to changes in its internal or external factors. This paper presents a new approach to ecological sensitivity assessment under the vulnerability research frame, and the sustainable supply of ecosystem services is employed as a measurement of human well-being under the influence of global change threats, such as land use change. The paper took Xiamen, a coastal city in Fujian Province, as an example to study ecological sensitivity to land use changes from the year 1987 to 2007. Firstly the ecological sensitivity mechanism of the major land use activities was analyzed, such as urban construction land expansion and reclamation. Then the Ecological Sensitivity Index (ESI) to land use change was defined as the ratio of the variation of ecosystem services value to the variation of Land Use Intensity, and the dynamic changes of ESI are calculated in detail from the year 1987 to 2007. Finally, using the layer calculation function of Geographic Information System (GIS) technology, the spatial distributions of ecological sensitivity were derivate. The results showed that construction land area increased significantly from 67. 48 km 2 in 1987 to 308. 21 km 2 in 2007, as much as 4. 57 times. The sustained expansion of construction land came from agricultural land and forest. From the year 1987 to 2007, shoreline length of Xiamen City experienced an increase-decrease process, from 290. 19 km in 1987, 343. 23 km in 1992, to 299. 93 km in 2007. The reclamation aimed at aquiculture causing the coastal line to zigzag and fragment, while the reclamation for transportation or construction land causing the shoreline smoother and shorter. The Land Use Intensity increased from 2. 44 in 1987 to 2. 52 in 2007, while the ecosystem services value showed a generally decreasing trend of 7. 39×10 9 Yuan in 1987 to 7. 02×10 9Yuan in 2007. The mechanism research of the ecosystem sensitivity to land use change indicated that Land Use Intensity and the ecosystem services value showed an opposite trend and Land Use Intensity increased inversely with the decline of the ecosystem services value. The ESI increased from 1. 50 in 1992 to 4. 94 in 1997, then decreased to 4. 12 in 2002, and finally increased slowly to 4.47 in 2007. Overall, in the past twenty years, the level of ecosystem affected by land use changes was not very severe. Most of the high ecological sensitivity areas located in the coastal area.
Based on an ETM, which utilized remote sensing software and geographical information systems software to construct a number of channel compositions, and by employing geometry correcting technology with the Universal Soil Loss Equation (USLE) as a pair of theory foundations, we used map algebra methods to assess the sensitivity of soil erosion in ecologically functional areas in Dongsheng, Erdos. Within this region were typical grassland hills areas, typical grassland districts, typical grassland desertification areas, desert grassland districts and urban residential districts. We classified the influence of precipitation, soil, topography and vegetation upon factors of soil erosion into five different degrees. As a result, we concluded research with an assessment map of each factor. We also drew integrated assessment maps of the sensitivity of soil erosion by overlapping these functions with ArcGIS. Through these assessments, clear possibilities for light, area coverage and spatial distribution patterns in soil erosion sensitivity came to light. Steppe hilly area of soil erosion sensitivity index SSj was 4.2, typical steppe plain area was 4.0, typical grassland desertification area was 4.6, desert grassland area of soil erosion sensitivity index was 5.0; This report also assesses the effective countermeasures controlling said soil erosion. The result will provide an important support base for partition management of ecological environments, the sustainable use of land resources, effective control of soil erosion, which will be of wide interest in the future.
For regional social and economic sustainable development, strengthening land ecosystem management at a provincial scale is prerequisite. One of the most important tools is to identify the critical or sensitive area that is easily degraded. So here in a methodology of eco-sensitivity assessment was proposed and a case of Yunnan Province was studied. Eco-sensitivity was defined as the possibility of formation and generation of eco-environment problems in a given region influenced by natural factors. Land eco-environmental problem considered are soil erosion, stone desertification, biology diversity, geological disaster and water environment. Based on the information of eco-environmental investigation of 2003 and previous studies, we have used GIS techniques to integrate the assessments of sensitivity to the five factors. The results show that moderately sensitive areas and highly sensitive areas are dominant, the properties to the total land area are 36. 67% and 46.93% respectively, and the insensitive area accounts for 10.15%, the extremely sensitive area share the smallest proportion, only accounts for 6.25%. Looked from the regional distribution that, the moderate sensitive type area has the distribution in each area of entire province, the highly sensitive area mainly distributes in the northeast and northwest of Yunnan as well as partial areas of Yunnan's west.
The output of natural eco-service function is eco-service efficiency; it can be divided into positive and negative eco-services. Rapid urbanization occupies amounts of non-construction areas that are important for maintaining local favorable environment; this process affects the natural eco-service functions, and results in deterioration of city' s eco-environment, in other words, the negative eco-service efficiency increases. As a typical rapidly urbanization city at the eastern of China, Changzhou's urbanization occupied lots of lands for eco-services, it caused many environmental problems. Under the support of GIS and RS technology, this paper used methods of grid analysis and complex ecological assessment, and established the spatial indexes system for complex eco-services efficiency assessment from both positive and negative eco-services of the current land use. The results show that there is about 64. 5 percent land' s complex eco-service is positive, and 35. 5 percent land's complex eco-service is negative. According to the city's current land use planning trend, it would result in more lands changing from positive eco-services into negative efficiency. The results provide a scientific reference for decision-making of local land use planning and management for urban future development.
Regionalization of soil and water conservation is a base for the planning of soil and water conservation in China. It can provide scientific basis for constructing healthy eco-environment and regional management and development. It makes a brief review of related regionalization of study and makes clear the concept of regionalization of soil and water conservation. In this paper, based on synthetical analysis of the characteristics of eco-environments of China, the principles, indices and nomenclature of the regionalization of soil and water conservation are proposed. Through the construction of the regionalization of soil and water conservation collaboration platform and data reporting system, combined with existing soil and water conservation research, this paper uses the top-down and bottom-up and the combination of qualitative and quantitative methods to build soil and water conservation regionalization preliminary scheme, with 8 regions, 41 sub-regions and 117 sections divided in China.
Soil erosion reduces crop productivity and creates negative impacts on water quality. Soil erosion by water has become a problem worldwide and as concerns about the environment continue to grow, soil erosion remains a very active area of scientific research. In this study, based on advanced remote sensing and Geographic Information Systems (GIS) technologies, the influences of precipitation, soil, topography and vegetation on soil erosion sensitivity are evaluated. An index system and the classification standard for soil erosion sensitivity assessment in the Tongbai–Dabie Mountainous area are established with soil erosion sensitivity being evaluated and analyzed in order to provide a scientific basis for controlling soil erosion and for making sound ecological engineering decisions. According to the regional conditions, sensitivity is classified into five levels: insensitive, mild, moderate, high and extreme. The distribution of erosion sensitivity for the region is analyzed and the various impacts are discussed. The results show that the sensitivity of the Tongbai–Dabie Mountainous area to soil erosion is relatively high, with 46.34% of the total area above the moderate level, and 44.30% and 9.36% rated at the mild and insensitive levels, respectively. In regards to the spatial distribution, the sensitivity levels decrease from south to north, with highly sensitive areas found mainly in the south in the areas of Jinzhai, Huoshan, Shangcheng, Yuexi, and Shucheng. The distribution of soil erosion sensitivity levels was very consistent with the intensity of soil erosion. Areas of high sensitivity are found to have severe areas of soil erosion, indicating that regional soil erosion is highly influenced by natural factors, although in some areas it is evident that the impact of human activities has played a significant role in exacerbating the problem. The results of this investigation serve to advance efforts to reduce the impacts soil erosion in the region and prevent further erosion in areas having high erosion sensitivities.
Soil erosion is a result of comprehensive effect of geographical environment factors. Based on the theory of Universal Soil Loss Equation and utilizing research results of domestic and foreign on soil erosion, this paper analyzed the influences of precipitation, soil texture, slope length and steepness, and land cover on the sensitivity of soil erosion, and assessed the soil erosion sensitivity in accordance with the standard of sensitivity grading and using the methods of mathematics model and GIS analysis. The results show that the overall sensitivity of soil erosion is higher in Tianshui, among which the area of the extremely sensitive and the highly sensitive reaches up to 6559.34km 2 9ÿ counting for 46.05 percentage of total area, while the area of insensitive is smaller, counting for 3.01 percentage of total area. Based on the comprehensively evaluating the spatial difference of soil erosion sensitivity of Tianshui, this paper advanced some countermeasures for land use planning of different sensitivity grades.
The four kinds of sites under different kinds of human disturbances, i.e. a farmland area, a rotational-grazing area, an over-grazing
area and a prohibited-grazing area, were selected in the typical region of the Alashan Desert of Inner Mongolia from April
to October in 2002, 2003 and 2004 respectively. The fluctuating tendency of rodent communities and the sensitive response
of their populations were studied using mark-recapture and trap-day methods. The four kinds of mark-recapture samples and
line samples were taken in different human disturbance areas. The area of the mark-recapturing sample was 0.95 hm2 and that of the line sample was 10 km2. The samples were collected every month in the mark-recapturing sites for four consecutive days and in line sites in April,
July and October every year. The variable matrix was composed of the numbers of captured rodents of the rodent communities.
The sensitive response of the populations in the communities was analyzed with principal component analysis (PCA). Results
showed that there were different types of rodent communities under different kinds of human disturbance on two scales in three
years. In each scale, there were large differences in both the number of species and the number of main population in the
rodent communities under different kinds of human disturbance on the farmland area and over-grazing area especially. The results
of PCA showed that the sensitive response of the populations of the commu nities was significantly different under different
kinds of human disturbance on the two scales in the three years. Cricetulus barabensis was the most sensitive on the farmland area, there were no differences in sensitive response of the various rodents on the
rotational-grazing area, and Dipus sagitta and Phodopus roborovskii were the most sensitive in the over-grazing area.
Identifying critical soil loss-prone areas is necessary to better control soil loss in the Xiangxi watershed, the river basin
nearest the Three Gorges Dam. A crucial element of this scheme is the development of a risk assessment model that can identify
critical potential soil loss areas for land use prioritization and soil conservation. An assessment model for the risk of
potential soil loss based on the revised universal soil loss equation and sediment delivery ratio was developed in this work.
The proposed model consists of five multiplied factors: the rain and runoff erosivity, soil erodibility, slope steepness and
length, vegetation cover, and sediment delivery. The risk of potential soil loss in the Xiangxi watershed was assessed using
the developed model integrated with the ArcGIS platform along with precipitation data, soil data, DEM, and MODIS NDVI images.
The risk values ranged from 0 to 478.18, and were categorized into four classes. The classification showed that critical and
sub-critical areas accounted for 4.48% and 6.05% respectively, of the entire Xiangxi watershed area. The results of the identification
of critical and sub-critical areas were verified by analyzing the relationship between the variations of the agricultural
land area and those of sediment discharge. Statistical relationship analysis between the distribution of critical/sub-critical
areas and two parameters (the cell distance to the nearest river channel and the slope) showed that the critical and sub-critical
areas for potential soil loss in the Xiangxi watershed assemble in the zone with a cell distance below 2,000m, or in the
zone with slopes above 25°.
KeywordsPotential soil loss–Risk assessment–Critical area–RUSLE–SDR
This paper reports the dynamic changes of soil and water loss in the red soil region of Southern China since the 1950s. The
red soil region covers eight provinces: Jiangxi, Zhejiang, Fujian, Anhui, Hubei, Hunan, Guangdong and Hainan. From the 1950s
to 1986, the annual rate of soil erosion increased by 3.4%. From 1986 to 1996 and from 1996 to 2000, the annual rates of soil
erosion decreased by 2.0% and 0.32%, respectively. Field surveys showed that from 2000 to 2005, the area of soil and water
loss decreased annually by 1.2%. This decrease was a result of large-scale erosion control activities across China. Although
the eroded soil has been restored, the restoration process is very slow and full restoration will take a long time. Our report
suggests that controlling soil and water loss is a challenging task, and additional measures must be taken to effectively
control the soil erosion in the red soil region.
Aiming at the ecological problems such as soil erosion, desertification, and salinization in the Jingnanxia-Heishanxia reach of Yellow River, the single-factorial ecological problem's sensitivity and the comprehensive ecological sensitivity of the reach were analyzed by GIS spatial analysis, grid computing and superposition, and RS image feature extraction. The results showed that the regions with medium- and high ecological sensitivities almost covered the whole study area, including the Wufo Town of Jingtai County, the Beiwan Town, Wulan Town, Mitan Town, Dongwan Town, and Santan Town of Jingyuan County, and the area between Doucheng and Hongliutan of Pingchuan District. The high, medium, and low sensitive areas should be accordingly programmed as forbidden, medium, and deep constructing areas. During the development process of regional hydropower, effective measures should be adopted to protect the ecological environment to achieve the sustainable development of the drainage area.
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