Spatiotemporal Evolution of Ecological Quality in Typical Karst Ecologically Fragile Areas Based on Remote Sensing Ecological Indexes

Fast and effective remote sensing monitoring is an important means for analyzing the spatio-temporal changes in ecological quality in fragile karst regions.This study focuses on Guanling Autonomous County,a national-level demonstration county for comprehensive desertification control.Based on Landsat TM/OLI remote sensing image data from 2005,2010,2015,and 2020,remote sensing ecological indices were used to analyze the spatio-temporal changes in ecological quality in Guanling Autonomous County from 2005 to 2020.The results show that:①the variance contribution rates of the first principal component for the four periods were 66.31%,71.59%,63.18%,and 75.24%,indicating that PC1 integrated most of the characteristics of the four indices,making the RSEI suitable for evaluating ecological quality in karst mountain areas;②the remote sensing ecological index grades have been increasing year by year,with an overall trend of improving ecological quality.The area of higher-grade ecological quality has increased spatially,while fragmented patches have gradually decreased,becoming more concentrated in the low-altitude areas in the northwest and east,and there is a trend of expansion towards higher-altitude areas;③the ecological environment quality in most areas has improved,with the improvement in RSEI spatio-temporal variation becoming more noticeable with increasing slope.Areas of higher-grade quality appeared in 2010,and the range of higher-grade quality expanded with increasing slope.

Spatio-temporal Evolution and Optimization of Landscape Ecological Risk in Karst Mountainous Areas

[Objective]The ecological vulnerability and landscape ecological risk of karst mountainous areas have increased as a result of enhanced disturbance of natural resources by human activities.This paper aimed to explore the characteristics of ecological risk evolution under different landscape patterns in the region,with a view to providing reference for land classification protection,sustainable use of resources and regional ecological risk optimization in karst mountainous areas.[Method]Taking Huangping County,a typical karst mountainous area,as an example,eight evaluation factors of natural and landscape patterns were selected to construct a landscape ecological risk evaluation model,to quantitatively explore the spatio-temporal evolution of landscape ecological risk and the trend of risk level transfer in the study area from^(2)010-2018,and to reveal the complex relationship between ecological risk and topography in karst mountainous areas.[Result]①From 2010 to 2018,land use types changed to different degrees,with the most amount of woodland transferred out(1627.37 hm^(2))and the most amount of construction land transferred in(1303.93 hm^(2));a total of 3552.31 hm^(2) of land was transferred,with a change ratio of 2.13%,and there was a significant conversion between construction land,arable land,and woodland.②From 2010 to 2018,the landscape ecological risk in the study area changed significantly,and the landscape ecological risk index decreased from 0.3441 to 0.1733,showing an upward and then downward trend;the landscape ecological risk of the whole region was dominated by low-risk and lower-risk zones,and the ecological risk level generally shifted from a high level to a low level,and the ecological environment was improved.③There was a negative correlation between ecological risk and topographic position,and high-risk zones were mainly distributed among low topographic zones;with the change of time,the advantage of risk level for the selection of topography was gradually weakened,and the influence of anthropogenic factors on the ecological risk of the landscape was becoming more and more prominent.[Conclusion]This paper can provide theoretical basis for land use optimization and ecological protection in karst mountainous areas.

Study on Sustainable Utilization of Resources of the Damp-heat Karst Mountainous Areas in China

Damp-heat karst mountainous areas are unique areas in terms of socialeconomic development, resource endowment and eco-environment in China, where natural resources are abundant,unique and diverse. However, fragile eco-environment, undeveloped economy and culture, and conflict of human and environment should not be ignored. In the research, a framework of integration of resource-development and environment-protection in damp-heat karst was designed on basis of resource and environment integration, which was applied to Daxin County in Guangxi Province. Furthermore, some integration models were proposed, including integration of development of characteristic agricultural resources and protection of eco-environment, integration of development of manganese ore resources and protection of eco-environment, integration of development of tourism resources and protection of ecoenvironment and integration of development of clean energy and protection of eco-environment.

ECOLOGICAL AND SOCIO-ECONOMIC REHABILITATION IN THE KARST OF SOUTHWEST CHINA

The Karst of Southwest China is a typical representative of poverty stricken region with impoverishment-degradation spiral. To essentially break away from this vicious circle, the local ecology, economy and society should be rehabilitated, and hence to strengthen the self-development capacity building of the localities. Two considerations are stressed in this article: (1) Poverty alleviation is a system project with great complexities. Any single approach is difficult to success and integrated measures should be taken. (2) Some typical and feasible areas should be selected to demonstrate the project of poverty alleviation and ecological, socio-economic reconstruction. Then, they can be used as a model to promote the sustainable development of the whole region. Based upon these ideals, a project entitled “Reversal of Impoverishment-Degradation Spiral in the Karst of Southwest China' was proposed and has been listed in 《Priority Programme for China's Agenda 21》.

Driving forest succession in karst areas of Chongqing municipality over the past decade

Background:Karst areas in southwestern China exhibit ecological degradation in the form of rocky desertification.Local governments launched large-scale afforestation and other ecological restoration programs to curb this trend.Soil thickness is a key limiting factor for vegetation restoration in Karst areas,but the relationship between ecological restoration and soil thickness remains unclear.Further,afforestation consumes large amounts of water,which impacts water supply in karst areas.In this study,we used GIS and statistical analyses to determine rocky desertification sensitivity and its driving factors in karst areas of Chongqing municipality over the past decade.Results:Soil thickness is one of the key factors that restrict ecological restoration of rocky desertification.From 2000 to 2010,rocky desertification sensitivity in karst areas was on the rise along with an increase in afforestation.Areas of high sensitivity were mainly distributed in Pengshui County,Wulong District,and Youyang County;Shizhu County had the lowest overall incidence of desertification.Spatial distribution of rocky desertification was significantly affected by rainfall and soil thickness.Regression analysis showed that the main factors controlling changes in rocky desertification in natural forest over time were precipitation which explained 23.73%of total variance,and soil thickness which explained 23.42%of total variance.Soil thickness and soil water content had a higher correlation coefficient(at 0.516)in natural forests than in planted forests.Conclusion:This study showed that increases in soil thickness in a karst area had a significant positive impact on the fragile ecological environment.This indicates that ecosystem restoration in karst areas will benefit from addressing soil thickness.

The research of Chinese karst ecological hydrology

Karst environment is very common in southwest China. Soil and vegetation are the most sensitive elements for the variation of karst environment. The weathering of carbonate is important soil formation mechanism in karst area, but its soil forming ability is so poor that the thickness of soil layer becomes thin by the water erosion, though the soil loss is insignificant but serious. The karst process, the ecology process, the hydrology process are three important circulation mechanisms in the karst multiple media environment. In the Chinese North and South karst area, the eco-environmental protection and restoration has already been the important part as the national territorial resources and the environmen- tal comprehensive development and management. The character of karst plants mainly depends on the environmental conditions, i.e. lack of water, richness of Ca, poor soil and shortage of organic matter. The plants have low growth pace and low life-form resource; it is vulnerable under the disturbance of irrational human activities. Therefore, the rocky desertification is the final result of karst ecosystem degradation. But ecological condition is severe in the North and South karst area, especially in the south karst stone mountainous area and the north arid karst area. There are many problems with the eco-environmental protection and restoration. This paper takes the karst multiple media environment as a core, comprehensively discusses the relations of the three processes – karst, hydrology, and ecology, and puts forward the direction of the research on karst ecology hydrology and the future.

ECOLOGICAL SECURITY EVALUATION OF SUSTAINABLE AGRICULTURAL DEVELOPMENT IN KARST MOUNTAINOUS AREA—A Case Study of Du'an Yao Autonomous County in Guangxi

Ecological security is the main task and applied field of present geography, resources and environment sciences and ecology. Ecological security evaluation will efficiently promote ecological security and environmental construction in regional land use. In this thesis, the authors put forward the index system of ecological security evaluation in karst mountainous area on three aspects, the pressure of resources and eco-environment, the quality of resources and eco-environment, and the ability of environmental protection and ecological improvement. Using the evaluation method with single index, based on the case study ofDu'an Yao Autonomous County of Guangxi Zhuang Autonomous Region, the system of synthetic regionalization of ecological agricultural economy was formed, which includes three regions, south region with basic security and synthetic agricultural development, east region with critical security and agriculture, forestry, animal husbandry balanced development, mid-west and south region with ecological insecurity and compounded agriculture and forestry management. Meanwhile, for these regions, the countermeasures of sustainable agricultural development were pointed out, which provide the basis and example for ecological regulation and control of sustainable agricultural development in counties ofkarst mountainous area.

Landscape structures of different rural landscape connectivity in typical plateau karst regions: Taking the Houzhai River area of Anshun City, Guizhou Province as an example

Landscape connectivity is important for energy and material flow in ecosystems as well as for the survival of species. The landscape structure influences and reflects the degree of landscape connectivity. In order to study the coupling relationship between landscape structure and connectivity and reveal the succession relationship between its structure and connectivity in the typical karst plateau area. The study analyzed the typical area of Houzhai River in Puding County, Anshun City, Guizhou Province, according to the landscape pattern index and probability landscape connectivity index. The results show:(1) The landscape structure of the study area A is mainly characterized by large patches and uniform distribution. The main land is woodland and cultivated land, and the overall landscape is low fragmentation.(2) The landscape structure of the study area B is mainly characterized by the clustering of a certain type of land cover and the uneven distribution of the patches, for example, cultivated land. Other types of patches are scatteredly distributed, and the overall landscape is highly fragmented.(3) The study area A, B in 100, 500, 1000, 2000, 3000, 5 distance thresholds of landscape connectivity were 1.55, 1.99, 2.26, 2.49, 2.58 and 0.02, 0.10, 0.15, 0.19, 0.20, respectively. The average landscape connectivity is 2. 18 and 0. 13, respectively. Study Area A has a higher degree of landscape connectivity than B. Landscape pattern indicators can represent the landscape structure and probability landscape connectivity index calculates the landscape connectivity in the study area. The results of the study can provide a basis for ecological restoration of plateau karst regions and well-oriented rural development planning.

Study on the Willingness to Pay the Tourists in the Ecological Environment Protection of Huashan Scenic Spot

In this paper, CVM method (conditional value evaluation method, also known as willingness investigation method) is used to investigate the willingness to pay about the ecological environment protection cost of Shaanxi Huashan scenic spot in July and August, 2013. By establishing the Logistic regression model, the per capita willingness to pay (WTP) of the tourists is calculated to be 79.2 yuan / person. The results show that the tourists' awareness of environmental protection is increasing day by day, and the visitors are fully aware of the importance of protecting the ecological environment. 57.85% of the tourists will be willing to pay, including civil servants, self-employed persons, college degree or above, family monthly income in the 8000-10000 yuan visitors will pay higher. This provides a reference for the sustainable development and development of ecotourism in Huashan Scenic Spot.

Integrated controlling technique of ecological environment in Shendong Mining Area

To enclose the interactive relation between the underground mining with suitable protection for surface ecological environments and surface prevention of ecological environments adapting to mining disturbing was researched and developed core of this technique. There are three aspects of controlling ecological environments, to dispose and renew before exploitation, to protect surface ecological environments in the exploitative process and to repair and build up after exploitation. Based on the moving law of overburden strata in shallow seam, the surface subsidence law and the growth law of vegetation in subsidence mine area, the integrated controlling technique has been developed synthetically by methods of theoretic analysis, laboratory simulation, numerical calculation, commercial test etc.. It includes the key techniques of aquifer-protective mining, filtering and purging of mine water through goaf, preventing and extinguishing fire in shallow seam no-rock roadway layout and waste disposal in underground, frame-building ecological functional sphere before exploitation, frame-building the ecological cycle using system after mining and so on.

Study on Ecological Footprints and Sustainable Development in Karst Area——Taking Anshun as an example

[ Objective] The aim was to study the ecological footprint and sustainable development in Karst Area. [ Method] By dint of statistical da- ta of Anshun City in 2008, the ecological footprint of Anshun City was calculated. The sustainable development of ecological system in Anshun City was analyzed from the angle of balance of supply and demand. [ Result] The per capita ecological capacity was 0.447 8 hm2/cap in 2008, per capi- ta ecological footprint was 2.309 0 hm2/cap, and ecological surplus of deficit was 1.861 2 hm2/cap. It meant the EF of the present region in terms of human activities had already exceeded the benchmark of system ecological carrying capacity. The supply of natural resources can＇t fully meet people＇s needs, and land use was unsustainable. The sustainable development of Karst area can be realized through changing people＇s production and life consumption model, building resources-saving social productive consumption system, depending scientific and technological development, improving production technology, using new technology, improving resources utilization effect and developing recycle economy. [Condusion] The study provided theoretical basis for sustainable development in Karst area.

THE RATIONAL UTILIZATION OF WATER RESOURCES IN IRRIGATED AREA OF THE YELLOW RIVER IN NINGXIA

The paper describes the water resources in the irrigated area of Ningxia, China, andthe methods for improving the utilization of the water resources, and puts forward somesuggestions so as to utilize the water resources rationally. The history of irrigation farming in Ningxia can be traced back to more than two thou-

Ecological risk assessment of Cd and other heavy metals in soil-rice system in the karst areas with high geochemical background of Guangxi,China

Karst areas are widely distributed in China,and the soil derived in these areas is enriched with trace elements and has the typical characteristics of high geochemical background.Therefore,soil ecological risk has gradually attracted extensive attention.In this study,1090 sets of rice grains and paired rhizosphere soils were collected as research objects from the outcropped karst areas of carbonate rocks in Guangxi,and the concentration characteristics and influencing factors of heavy metals,such as Cd and As,in rice grains and the corresponding soils were studied.According to the Chinese Soil Environmental Quality Standard(GB 15618-2018),the proportion of karstic soil samples in Guangxi with heavy metal(As,Cd,Cr,Cu,Hg,Ni,Pb and Zn)concentrations that exceed the standard risk screening values was generally greater than that of surface soils in China or non-karstic soils in Guangxi.Notably,Cd and As were the most prominently enriched heavy metals in soils.According to the Chinese Food Safety Standard(GB 2762-2017),Pb in rice grains from the studied area did not exceed the standard;the exceedance rates of Cr,Hg,and inorganic As were only about 1%;and the exceedance rate of Cd was 12.5%.Soil Cd concentration increased gradually whereas the concentration and exceedance rate of Cd in rice grains decreased gradually with the increase of soil pH.Specifically,the exceedance rate of Cd in rice grains was only 4%when soil pH>6.5.The results indicated that the risk screening values of Cd element in the Chinese Soil Environmental Quality Standard are not satisfactorily applicable to the ecological risk assessment of Cd in karstic soils.Therefore,the recommended threshold values for the safe utilization and risk control of Cd in karstic soils was proposed so as to provide a basis for soil environmental quality hierarchization,pollution risk control and land safety zoning of agricultural land in karst areas in China.

Major Problems and Countermeasures for the Establishment of Ecological Compensation Systems for National Key Ecological Function Areas

At the end of the 1990 s China started to construct an ecological compensation system for national key ecological function areas. An eco-compensation system focusing on the ＂Transfer Payment of National Key Ecological Function Areas＂ has been established. The current eco-compensation system has played a positive role in improving the ecological environment of national key ecological function areas; but the ecological effect is weakening due to existing problems in the eco-compensation system such as unreasonable calculation of compensation standards, poor expression of rights and interests of stakeholders, simple sources of capital and modes of compensation. For better development, the eco-compensation system should be improved by（i） adhering to the combination of vertical compensation（oriented） and horizontal compensation（auxiliary） on the whole and establishing a transfer payment system of eco-compensation at national scale;（ii） defining the compensation standard according to ecological protection costs, development opportunity costs and ecological service values and adding indicators that reflect economic green transformation to evaluate compensation effects;（iii） gradually building a utilization system of eco-compensation funds in which multi-stakeholders participate and establishing a green development-oriented system to evaluate the performance of local governments; and（iv） cultivating a new business pattern where ecological services are the product, to grow the ecological service industry.

Changes in Vegetation and Assessment of Meteorological Conditions in Ecologically Fragile Karst Areas

Meteorological conditions have an important impact on changes of vegetation in ecologically fragile karst areas.This study aims to explore a method for quantitative evaluation of these meteorological conditions. We analyzed the changing trend of vegetation during 2000–2018 and the correlations between vegetation changes and various meteorological factors in karst rocky areas of Guangxi Zhuang Autonomous Region, China. Key meteorological factors in vegetation areas with varying degrees of improvement were selected and evaluated at seasonal timescale. A quantitative evaluation model of comprehensive influences of meteorological factors on vegetation was built by using the partial least-square regression(PLS). About 91.45% of the vegetation tended to be improved, while only the rest 8.55% showed a trend of degradation from 2000 to 2018. Areas with evident vegetation improvement were mainly distributed in the middle and northeast, and those with obvious vegetation degradation were scattered. Meteorological factors affecting vegetation were significantly different among the four seasons. Overall, high air humidity, small temperature difference in spring and autumn, and low daily minimum temperature and air pressure were favorable conditions. Low temperature in winter as well as high temperature in summer and autumn were unfavorable conditions. The Climate Vegetation Index(CVI) model was established by PLS using the maximum, minimum, and average temperatures;vapor pressure;rainfall;and air pressure as key meteorological factors. The Enhanced Vegetation Index(EVI) was well fitted by the CVI model, with the average coefficient of determination(r2) and root mean square error(RMSE) of 0.856 and 0.042, respectively. Finally, an assessment model of comprehensive meteorological conditions was built based on the interannual differences in CVI. The meteorological conditions in the study area in 2014 were successfully evaluated by combining the model and selected seasonal key meteorological factors.

A climatic environmental performance assessment method for ecological city construction:Application to Beijing Yanqi Lake

In contrast to the input perspective for evaluating planning metrics, this research takes the climatic environmental output effects as the starting point for assessing ecological city construction. Based on approaches such as observation data analysis, meteorological model simulation, and remote sensing, a set of climatic environmental performance assessment methods is developed and established. These methods mainly focus on surface ventilation assessment and urban thermal environment assessment. With the Yanqi Lake ecological development demonstration area located in Huairou district, Beijing as an example, the assessment of the local climatic environment before and after the construction are conducted, and relevant policy suggestions for urban planning and construction are presented. The results show that after development, the ventilation capacity will decrease overall and the ventilation potential index will decrease from 0.53 to 0.44. While this is not a large reduction, and is still at a favorable level, the ventilation potential in some local areas will markedly decrease. Furthermore, the thermal environment will become poorer to some extent; the urban heat island(UHI) area and intensity will increase compared with the current situation;continuous heat islands may occur in local areas; the UHI potential index of the core area will rise from 0.0878 to 0.1217(still a favorable level).Therefore, urban surfaces should be carefully developed and arranged during planning. It is suggested that the negative impacts of large areas of urban construction on the local climatic environment in the Yanqi Lake could be mitigated by 1) strengthening the airflow by introducing fresh,cold, northwesterly air via constructed ventilation corridors, 2) increasing the number of ecological cold sources, particularly for water bodies and green belts to prevent the UHI in the southern region of Yanqi Lake from becoming linked with each other, and 3) considering a pre-program before sub-domain and building planning to obtain optimum building locations. Different construction standards should be developed for different ventilation potential and UHI intensity levels. For strong heat island areas, land areas should be reserved to serve as cold sources.

Study on Fishery Ecological Environment and Fish Species Diversity in Yantan Water Area

Through analysis on water quality,planktonic organism,fish resources,and fish species diversity in Yantan water area,this paper evaluated current situation of quality of fishery ecological environment in Yantan water area. The survey recorded all 52365 fishes and 1410. 2kg catches obtained by fishermen in half a year,and more than 98% catches are small fishes. The Shannon-Weiner diversity index of Yantan water area is 0. 162,Wilhm improvement index is 1. 814,DG- Findex is 0. 083,and the index of fish species diversity is far lower than other water areas. The average quantity per unit of phytoplankton is 1. 0134 million ind. / L,and the average quantity per unit of organisms is 1. 1151 mg / L. The average quantity per unit of zooplankton is 459. 6 ind. / L,and the average quantity per unit of organisms is 0. 6422 mg / L. Evaluation results indicate that water quality and planktonic organism in Yantan water area are basically normal,but fish resources are increasingly exhausted,fish resource composition is not reasonable,and fish species diversity is extremely low. From the perspective of biomanipulation,it is required to restore fishery ecological environment of reservoir area through restoring normal composition of aquatic organisms.

Analysis on Ecological Sensitivity in Jinjie Mining Area Based on RS and GIS

[Objective] The aim was to study ecological sensitivity in Jinjie mining area. [Method] Taking Jinjie mining area as study object, based on RS and GIS technology, ecological sensitivity in Jinjie mining area was assessed comprehensively from the aspects of soil erosion, desertification and geological disaster by means of multivariate weighted stack method. [Result] Most of Jinjie mining area belonged to extremely high sensitive or high sensitive area which accounted for 73.35% of total area, with little moderate sensitive (19.50%), low sensitive (0.96%) and non-sensitive area (6.19%); the unreasonable development of mineral resources would damage its ecological environment severely. [Conclusion] The study could provide theoretical foundation for the protection of ecological environment in mining area.

Control Measures of Soil Erosion in a Typical Construction Project Area ( Dina 2 Gas Field)

To treat the relationship between project construction and ecological environment and effectively prevent new soil erosion during the construction, according to the project layout, soil erosion distribution as well as natural and socio-economic conditions, the control measures of newly increased soil erosion along the project were carried out based on site survey and analysis of relevant information. In addition, adhering to the prin- ciple of partition prevention and treatment, some guiding prevention and control measures of the natural zone passed by the project and soil erosion control district were determined, which provided scientific references and technical support for the rational layout of water and soil conservation and ecological restoration measures in Dina 2 gas field.

矿区生态环境调研评估与修复方案研究

以某矿区为例,对矿区水文环境、工程地质、基本设施等生态环境进行调研分析,结合调研结果预估矿山地质环境影响,分析矿区采矿活动对各类矿区地质环境因素所造成的影响。根据地质环境影响预测评估结果,实施矿区地质环境治理分区,介绍工程生态环境修复方案设计,为后续矿区生态环境修复方案设计,提供调研评估方法与修复设计方案参考。