Karst Mountain Area Research Articles

基于形态学空间格局和空间主成分的贵阳市中心城区生态网络构建

PDF HTML阅读 XML下载 导出引用 引用提醒 基于形态学空间格局和空间主成分的贵阳市中心城区生态网络构建 DOI: 10.5846/stxb202012213241 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（32060367）；贵州省科学技术基金重点项目（黔科合基础[2020]1Z011）；贵州省科技支撑计划项目（黔科合支撑[2021]一般458） Construction of ecological network in downtown of Guiyang city based on morphologically spatial pattern and spatially principal component analysis Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:喀斯特多山地区，城市扩展过程中大量自然山体镶嵌入城，形成具有多种生态系统服务功能的城市遗存自然山体。但在城市内部致密化发展过程中，这些城市遗存山体常被城市建设用地孤立和包围，形成人工干扰场中的生态孤岛。生态网络的构建既有利于城市遗存自然山体自然资源保护，又有助于丰富城市绿色基础设施生态系统服务功能。以喀斯特地区典型的多山城市——贵阳市行政区为研究对象，综合利用形态学空间格局分析法和景观连通性识别中心城区生态源地，基于主成分分析确定研究区综合阻力面，通过最小累积阻力模型、重力模型和水文分析等方法，识别并优化关键衔接廊道及节点，在中心城区行政区和建成区两个尺度构建研究区生态网络。结果表明：（1）行政区生态源地分布整体呈现"南北相望"的格局，建成区生态源地集中在中部；（2）研究区综合生态阻力高值主要集中在研究区中部，呈放射状向外扩散，综合生态阻力低值主要分布在研究区周边，以大型林地斑块为主；（3）行政区极重要、重要、一般廊道数分别为15、21、69，极重要廊道集中分布在北部，建成区极重要、重要、一般廊道数分别为37、113、227条，极重要廊道主要分布在建成区中部；（4）行政区和建成区一类生态节点分别为29、25个，二类生态节点33、17个。最终通过叠加行政区和建成区生态网络要素，形成贵阳市中心城区生态网络，研究结果能为贵阳市中心城区在未来用地空间上协调生态保护与城市发展提供科学合理的参考。 Abstract:In the karst mountainous area, with the urban expansion, a large number of natural mountains have been embedded into the urban built-up area, forming the urban remnant natural mountains which have various ecosystem service functions. However, in the process of dense development within the urban area, these urban remnant mountains were often isolated and surrounded by the urban construction land, forming the ecological islands in the artificial interference field of urban built-up area. Construction of ecological network of the mountainous urban could be not only conducive to the protection of natural resources of urban remnant natural mountains, but also beneficial to enrich the service functions of urban green infrastructure ecosystem. Taking the downtown of Guiyang, a typical mountainous city in karst area, as research area, we comprehensively used morphologically spatial pattern analysis (MSPA) and landscape connectivity to identify ecological sources and determined the comprehensive resistance area based on the principal component analysis. We also identified and optimized the key connection corridors and nodes through the minimum cumulative resistance model (MCR), and constructed the ecological network at two scales of the administrative area and the built-up area of the research area. The results showed that:1) the overall distribution of ecological sources in the administrative region presented a pattern of "north and south facing each other", and the ecological sources in the built-up area were concentrated in the central part; 2) The high values of comprehensive ecological resistance were mainly concentrated in the middle of the study area and radially spread outwards, while the low values were mostly distributed in the periphery of the study area with large forest patches; 3) The number of essential, important and general corridors in the administrative region were 15, 21 and 69 respectively. The essential corridors were concentrated in the north of the study area, meanwhile, the number of essential, important and general corridors in the built-up area were 37, 113 and 227 respectively, and the essential corridors were mainly distributed in the middle of the built-up area; 4) There were 29 and 25 ecological nodes in the administrative and built-up areas, and 33 and 17 second-class ecological nodes, respectively. Finally, by superposition the ecological network elements of administrative region and built-up areas, the ecological network of the downtown of Guiyang City was constructed. This study could provide scientific and reasonable reference for coordinating ecological conservation and urban development in the central urban area of Guiyang city. 参考文献 相似文献 引证文献

基于地理探测器的喀斯特山区生态系统服务关系分异特征及驱动力解析——以贵州省为例

PDF HTML阅读 XML下载 导出引用 引用提醒 基于地理探测器的喀斯特山区生态系统服务关系分异特征及驱动力解析——以贵州省为例 DOI: 10.5846/stxb202109012470 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学青年基金项目（42001090）；重庆市教委科学技术研究项目（KJQN202000512） Differentiation characteristics and driving factors of ecosystem services relationships in karst mountainous area based on geographic detector modeling:A case study of Guizhou Province Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:生态系统服务关系的空间异质性及其驱动机制分析一直都是喀斯特生态系统服务研究的关键问题。以典型喀斯特山区--贵州省为例，选取植被净初级生产力(NPP)，土壤保持(SC)和产水(WY)3类生态系统服务，在对其进行准确估算的基础上，采用相关分析法、均方根误差法从多角度剖析生态系统服务关系变化及其空间分异规律，借助地理探测器对生态系统服务关系变化的驱动机理进行解析。结果表明：①2000-2015年贵州省NPP、土壤保持、产水服务均值均呈增长趋势，其中，NPP和土壤保持服务在研究区东北部及西北角增长最显著，产水服务在研究区东南部增加最明显。②研究时段内，区域生态系统服务关系以协同为主，只是协同关系在减弱并有向权衡发展的趋势。③不同背景条件下区域生态系统服务关系具有明显的分异特征。相较于白云岩，NPP与土壤保持的权衡度在石灰岩上更大；土壤保持与NPP的权衡度在地势平缓的岩溶盆地上较大，产水服务与NPP、土壤保持间的权衡度在陡峭的岩溶槽谷(峡谷)上更大；产水服务与土壤保持间的权衡度随着植被覆盖度的增加而逐渐增大。④地理探测器结果表明：造林总面积是影响NPP与土壤保持间权衡关系变化的主导因子，降水总量已成为制约NPP与产水服务间协同的最主要因子，高程和人均国内生产总值(GDP)是影响土壤保持与产水服务间关系的最主要因子；因子间的交互影响均高于单因子的影响。研究深化了喀斯特地区生态系统服务权衡/协同关系变化的机理解析研究，为喀斯特生态系统有效保护和管理提供了科学参考。 Abstract:The spatial heterogeneity of ecosystem services relationships and their driving mechanisms have always been the research focus regarding karst ecosystem services. Taking Guizhou Province, a typical karst mountainous area, as an example, this study selected three ecosystem services:net primary productivity (NPP), soil conservation (SC), and water yield (WY). Based on the accurate estimation of three ecosystem services through the Carnegie-Ames-Stanford approach (CASA) model, the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model and the water balance formula, the spatio-temporal change and differentiation characteristics of ecosystem services relationships were analyzed using correlation analysis and root mean square error (RMSE). The driving mechanisms of changes in ecosystem services relationships were then analyzed using a geographic detector modeling. The results showed that:① from 2000 to 2015, the average values of NPP, SC, and WY in Guizhou Province showed an increasing trend. In terms of spatial distribution, NPP and SC presented an increasing trend in the northeast and northwest corner of the study area. The WY increased in the southeastern study area. ② During the study period, the relationships of regional ecosystem services were mainly synergistic, but the synergistic relationship was weakening, accompanied by a trade-off trend. So, due attention should be given to the coordination of ecosystem services relationships. ③ The relationship of regional ecosystem services under different conditions had obvious differentiation characteristics. Compared with dolomite, the trade-off intensity between NPP and SC was greater on limestone; the trade-off intensity between SC and NPP was greater on flat karst basins, and the trade-off intensity between WY and NPP, WY and SC was greater on steep karst slot valley (canyons). The trade-off intensity between WY and SC gradually increased with the increase in vegetation coverage. ④ The results of the geographic detector modeling showed that the total afforestation area was the leading factor affecting the trade-off change between NPP and SC. The total precipitation was the main factor restricting the collaboration between NPP and WY. The elevation and per capita gross domestic product (GDP) were the main factors affecting the relationship between SC and WY. Meantime, the explanatory power of the interaction of any two factors was higher than that of the single factor, indicating the influence intensity of the factor was obviously increased after the interaction. In the future, attention should be paid to multi-factors and their interactions. This study provided deeper insights into the mechanisms of the trade-off/synergy changes among ecosystem services in the karst area, and a scientific reference for the effective protection and management of the karst ecosystem. 参考文献 相似文献 引证文献

Effects Of Fractal Dimension and Soil Erodibility on Soil Quality in an Erodible Region: Evidence from a Karst Mountainous Area

Effects Of Fractal Dimension and Soil Erodibility on Soil Quality in an Erodible Region: Evidence from a Karst Mountainous Area

Gray Forecast of Ecosystem Services Value and Its Driving Forces in Karst Areas of China: A Case Study in Guizhou Province, China.

A sound ecosystem is the prerequisite for the sustainable development of human society, and the karst ecosystem is a key component of the global ecosystem, which is essential to human welfare and livelihood. However, there remains a gap in the literature on the changing trend and driving factors of ecosystem services value (ESV) in karst areas. In this study, Guizhou Province, a representative region of karst mountainous areas, was taken as a case to bridge the gap. ESV in the karst areas was predicted, based on the land use change data in 2009–2018, and the driving mechanisms were explored through the gray correlation analysis method. Results show that a total loss of CNY 21.47 billion ESV from 2009 to 2018 is due to the conversion of a total of 22.566% of the land in Guizhou, with forest land as the main cause of ESV change. By 2025 and 2030, the areas of garden land, water area, and construction land in Guizhou Province will continue to increase, whereas the areas of cultivated land, forest land, and garden land will decline. The total ESV shows a downward trend and will decrease to CNY 218.71 billion by 2030. Gray correlation analysis results illuminate that the total population and tertiary industry proportion are the uppermost, among all the driving factors that affect ESV change. The findings in this study have important implications for optimizing and adjusting the land use structure ecological protection and will enrich the literature on ESV in ecologically fragile areas.

Landslide Displacement Prediction Method Based on GA-Elman Model

The deformation process of landslide displacement has complex nonlinear characteristics. In view of the problems of large error, slow convergence and poor stability of the traditional neural network prediction model, in order to better realize the accurate and effective prediction of landslide displacement, this research proposes a landslide displacement prediction model based on Genetic Algorithm (GA) optimized Elman neural network. This model combines the GA with the Elman neural network to optimize the weights, thresholds and the number of hidden neurons of the Elman neural network. It gives full play to the dynamic memory function of the Elman neural network, overcomes the problems that a single Elman neural network can easily fall into local minimums and the neuron data is difficult to determine, thereby effectively improving the prediction performance of the neural network prediction model. The displacement monitoring data of a slow-varying landslide in the Guizhou karst mountainous area are selected to predict and verify the landslide displacement, and the results are compared with the traditional Elman neural network prediction results. The results show that the prediction results of GA-Elman model are in good agreement with the actual monitoring data of landslide. The average error of the model is low and the prediction accuracy is high, which proves that the GA-Elman model can play a role in the prediction of landslide displacement and can provide reference for the early warning of landslide displacement deformation.

Assessing the degree of soil erosion in karst mountainous areas by extenics

The ecological environment of karst mountainous areas is fragile, and soil erosion has become an important factor restricting the social and economic development of these regions. How can the degree of soil erosion be scientifically assessed with a reasonable evaluation method? What is effect of the ecological environmental control measures? This study used extenics to assess the degree of soil erosion in karst mountainous areas. The typical karst mountainous area of Guizhou Province was used as the research object. In this study, a soil erosion monitoring indicator system for karst mountainous areas was developed, an evaluation model based on extenics was established, and an index correlation function and comprehensive correlation function were designed to assess the soil erosion of the karst mountainous areas. The key results were as follows. In the soil erosion monitoring index system, the soil nutrient indexes, soil erosion modulus, rock exposure, diversity index, flood season rainfall, population density and natural population growth rate had significant effects on soil erosion in the karst mountainous area. Additionally, we determined the grading standards for soil erosion intensity in typical karst mountains. Finally, the evaluation model was applied to a case study. The status of water and soil conservation was as follows: XW > ML > SB > ZS. These results provide new insights into the evaluation method, namely, extenics, which is helpful for conveniently, quickly and scientifically assessing soil erosion.

Population distribution characteristics and its relationship with natural factors in karst mountainous areas of Northwest Guangxi

The smallest administrative unit of the sixth national census-township (town) is selected as the basic unit, the population spatial distribution characteristics at the township (town) level in karst mountainous areas of northwest Guangxi are analyzed by using Lorenz curve and spatial correlation analysis method, and the influence intensity of natural factors on regional population spatial distribution is detected by using geographic detector method. The results show that: 1. the spatial distribution of population at the township (town) level has the characteristics of imbalance, showing generally significant positive correlation and certain aggregation; 2. there are significant differences in the impact of the spatial distribution of various natural factors on the population distribution. For the towns without karst distribution in the northwest and central south of the study area, the population density increases with the increase of factors conducive to human residence, but the average population density is only 79 people / km2. In the towns with karst distribution in the East and south, the spatial distribution of population density and natural factors is not a simple increase or decrease relationship, but fluctuates with the change of karst distribution area. 3. The factor detection results of the geographic detector show that the altitude has the greatest impact on the spatial distribution of population. The interactive detection results show that the impact intensity of any two natural factors after superposition and interaction presents nonlinear enhancement and two factor enhancement. It can be seen that the karst mountain area in northwest Guangxi is similar to other areas. Altitude is one of the main factors affecting the spatial distribution of population, but the river network density and unique geological landform of karst mountain area have a strong catalytic effect on the spatial distribution of population. The superposition and interaction with other factors can further strengthen the impact on population distribution.

A novel‐optimal monitoring model of rocky desertification based on feature space models with typical surface parameters derived from LANDSAT_8 OLI

AbstractPrevious studies monitoring the spatial distribution of rocky desertification have used single indices, a comprehensive index, or image classification. However, these approaches could not distinguish between the degrees of rocky desertification as they did not consider various influencing factors and their interactions. To avoid the above shortcomings, this study used the feature space model and seven typical land surface parameters to establish two categories of rocky desertification model: (1) a point‐to‐point model; and (2) a point‐to‐line model. A novel model for the optimal monitoring of rocky desertification was then proposed, which could take the comprehensive impacts of the human‐nature system on the process of rocky desertification. The results showed that: (1) the feature space models provided a novel approach to large‐scale monitoring of rocky desertification; (2) the point‐to‐line model incorporating the rock bare index (RBI)‐dryness index feature space showed the optimal applicability for monitoring of rocky desertification, with a precision of 93.4%; and (3) the RBI performed the best in indicating the process of rocky desertification, with an average precision of 88.5%. The results of this study can act as a reference within the investigation of the spatiotemporal evolution of rocky desertification for karst mountain areas.

Crops planting structure and karst rocky desertification analysis by Sentinel-1 data

Abstract Accurate crop planting structure (CPS) information and its relationship with the surrounding special environment can provide strong support for the adjustment of agricultural structure in areas with limited cultivated land resources, and it will help regional food security, social economy, and ecological balance adjustment. However, due to the perennial cloudy, rainy, and scattered arable land in Karst mountainous areas, the monitoring of planting structure by traditional remote sensing methods is greatly limited. In this regard, we focus on synthetic aperture radar (SAR) remote sensing, which can penetrate clouds and rain, without light constraints to image. In this article, based on parcel-based temporal sequence SAR, the CPS in South China karst area was extracted by deep learning technology, and the spatial coupling relationship between CPS and karst rocky desertification (KRD) was analyzed. The results showed that: (a) The overall accuracy of CPS classification was 75.98%, which proved that the geo-parcel-based time series SAR has a good effect for the CPS mapping in the karst mountainous areas; (b) Through the analysis of the spatial relationship between the planting structure and KRD, we found that the lower KRD level caused the simpler CPS and the higher KRD grade caused more complex CPS and more richer landscape types. The spatial variation trend of CPS landscape indicates the process of water shortage and the deepening of KRD in farmland; (c) The landscape has higher connectivity (Contagion Index, CI 0.52–1.73) in lower KRD level and lower connectivity (CI 0.83–2.05) in higher KRD level, which shows that the degree of fragmentation and connection of CPS landscape is positively proportional to the degree of KRD. In this study, the planting structure extraction of crops under complex imaging environment was realized by using the farmland geo-parcels-based time series Sentinel-1 data, and the relationship between planting structure and KRD was analyzed. This study provides a new idea and method for the extraction of agricultural planting structure in the cloudy and rainy karst mountainous areas of Southwest China. The results of this study have certain guiding significance for the adjustment of regional agricultural planting structure and the balance of regional development.

Differentiation Characteristics of Calcium Bioabsorption Capacity of Dominant Tree Species with Altitude in Typical Karst Mountain Area

Differentiation Characteristics of Calcium Bioabsorption Capacity of Dominant Tree Species with Altitude in Typical Karst Mountain Area

Impacts of biochar-based fertilization on soil arbuscular mycorrhizal fungal community structure in a karst mountainous area.

The application of biochar-based fertilizer can improve soil properties in part by stimulating microbial activity and growth. Karst ecosystems, which make up large areas of Southwest China, are prone to degradation. Understanding the response of arbuscular mycorrhizal fungal (AMF) community structure to biochar-based fertilizer application is of great significance to karst soil restoration. A field experiment was conducted in a typical karst soil (calcareous sandy loam) in Southwest China. A high-throughput sequencing approach was used to investigate the effect of biochar-based fertilization on AMF community structure in the karst soil. With the control (CK), compost with NPK fertilizer (MF), biochar (B), a lower amount of biochar with compost and NPK fertilizer (B1MF), biochar with compost and NPK fertilizer (BMF), and a higher amount of biochar with compost and NPK fertilizer (B4MF), the field trials were set up for 24 months. Soil amendments increased soil nutrient content and AMF diversity. The composition and structure of the AMF community varied among the treatments. AMF community composition was significantly impacted by soil chemical properties such as TC (total carbon), TN (total nitrogen), TP (total phosphorus), and AP (available phosphorus). Furthermore, network analysis showed that biochar-based fertilization increased the scale and complexity of the microbial co-occurrence network. Biochar-based fertilization enabled more keystone species (such as order Diversisporales and Glomerales) in the soil AMF network to participate in soil carbon resource management and soil nutrient cycling, indicating that biochar-based fertilizer is beneficial for the restoration of degraded karst soils.

Effects of biochar-based fertilizer on soil bacterial network structure in a karst mountainous area

The karst ecosystem is prone to degradation and accounts for a large proportion of land surface in southwestern China. In order to improve the nutrient status and microbial community structure of karst soils for the restoration of vegetation, we tested a management strategy of combining biochar, compost and chemical fertilizer to amend karst soil. With CK as the control, M as manure compost, B as wood biochar, and F as chemical fertilizer, field trials were set up with eight treatments (CK, M, F, B, M + F, B + M, B + F, and B + M + F). Our results showed that the biochar treatments had higher bacterial diversity and soil nutrient content than no-biochar treatments, and the compost treatments had higher bacterial diversity and soil nutrient content than no-compost treatments. Cluster and LEfSe analyses indicated that the structure and composition of bacterial community varied with different treatments; the compost network (M, MF, BM and BMF) had a higher number of nodes, links and modules than the no-compost network (CK, F, B and BF), and the biochar network (B, BF, BM and BMF) was more complex than the no-biochar network (CK, F, M and MF). Soil properties (soil organic carbon, available nitrogen, available phosphorus) were significantly correlated with soil bacterial networks. The addition of both organic compost and biochar enlarged the complexity of microbial-related networks and enhanced the soil nutrient status, indicating that biochar-based fertilizer was effective for soil restoration in degraded karst landscape.

Biochar-based fertilizer amendments improve the soil microbial community structure in a karst mountainous area

Biochar-based fertilizer amendment can improve soil properties partly due to stimulated microbial activities and growths. The karst ecosystem is prone to degradation and accounts for a large proportion of southwest China. Understanding of the response of the microbial community structure to biochar-based fertilizer application is of great significance in karst soil restoration. A field experiment located in southwest China was conducted in typical karst soil, and a high-throughput sequencing approach was used to investigate the effect of biochar-based fertilizer application on microbial community structure in karst soil. Field trials were set up for 24 months using the following treatments: control (CK), compost plus NPK fertilizer (MF), biochar (B), less biochar (half the quantity of biochar in B) plus compost and NPK fertilizer (B1MF), biochar plus compost and NPK fertilizer (BMF), and more biochar (double the quantity of biochar in B) plus compost and NPK fertilizer (B4MF). The results elucidated that BMF and B4MF treatments had higher contents of soil carbon and soil nutrients N, P, and K than the other treatments. Soil microbial abundance and diversity were significantly increased by biochar-based fertilizer amendments (BMF and B4MF), compared to CK (P < 0.05). BMF and B4MF treatments significantly increased the relative abundance of dominant microorganisms, compared to CK (P < 0.05). The difference in the composition of indicator microbes between each treated group indicated that soil amendments altered the microbial community structure. There was a strong correlation between soil properties (soil C-, N-, and P-fractions) and microbial community structure. Furthermore, network analysis revealed that the addition of biochar-based fertilizer increased the scale and complexity of the microbial co-occurrence network. To summarize, the application of biochar-based fertilizer enabled more keystone species in the soil microbial network to participate in soil carbon resource management and soil nutrient cycling, indicating that biochar-based fertilizer is beneficial for the restoration of karst-degraded soils.

Spatial differentiation of the impact of transport accessibility on the multidimensional poverty of rural households in karst mountain areas

Spatial differentiation of the impact of transport accessibility on the multidimensional poverty of rural households in karst mountain areas

Spatial differentiation and driving mechanism of rural water security in typical “engineering water depletion” of karst mountainous area—A lesson of Guizhou, China

Southwest China gets abundant rainfall, but in its rural areas, there is a severe shortage of water resources for irrigation and drinking. A case study was conducted in the Guizhou Province, which has the most concentrated karst distribution worldwide. The rural water security index was constructed, and Geodetector and ArcGIS were employed to systematically analyze the status quo, spatial differentiation, and driving mechanism of water security in rural areas of Guizhou in 2016. The results showed that (1) there was obvious spatial variation in the rural water security index in the study area, with only 3.85% of areas being maximally safe, and 20.51%, 35.89%, 15.38%, and 24.36% being sub-optimally safe, moderately safe, unsafe, and extremely unsafe, respectively. The spatial distribution of the rural water security index, it generally coincides with a gradual decay from the economically developed areas to the periphery. The water security of the geographical environment is inferior to those of domestic water and water for agricultural production. (2) For Guizhou Province, economic and social factors, such as the disposable income of rural residents and the incidence of impoverishment, were critical factors influencing rural water security. The critical influencing factors vary greatly among prefectures; however, there are some common factors that affect rural water security, such as the incidence of impoverishment, the penetration rate of rural piped water, the percentage of primary industry, and the percentage of karst area. The maximum value of the interactive driver of the percentage of groundwater and the disposable income of rural residents was 0.812, indicating that the interaction between the high percentage of groundwater caused by karst development and the low disposable income of rural residents was the primary reason for the low rural water security. (3) Rural water security was largely influenced by poor socioeconomic development, resulting in a low level of security and the availability of public water facilities and domestic water in rural areas. Significant improvements in rural water security depend on ameliorating the water security of agricultural production and domestic water, rather than improving the geo-environmental conditions of water resources at extremely high costs.

A Method of Identifying the Critical Source Areas for Phosphorus Loss in Geological Phosphorus-rich Watersheds

The principal cause of eutrophication in some freshwater systems is diffuse phosphorus (P) loss. The identification of critical source areas (CSAs) is identified to be the most effective way to minimize the difficulty of nonpoint source (NPS) P pollution management in watersheds. How to efficaciously identify CSAs for phosphorus loss in geological phosphorus-rich (GPR) watersheds is still a challenging hassle. An assessment approach primarily based on QGIS was applied to assess the risk of P loss and identified CSAs for a case study in the Huangbai River watershed of south China, which is a typical geological P-rich (GPR) watershed. In the modified P ranking scheme, total soil P (TP) content in various land use types was used as a source factor; the topographic index (TI) and distance-to-streams were considered as transport factors. P index calculation results showed that 92.2% of the watershed was low risk area, while 7.8% for medium and high risk of P loss. Meanwhile, higher risk areas were associated with the shorter distances from the stream, higher TI, and higher soil P content. Also, CSAs are normally located in phosphate mining sites and concentrated arable land in the karst mountainous areas. The introduction of a simplified P index scheme provides a convenient and practical tool to target CSAs for P loss from GPR areas in data-poor watersheds, thus assisting decision makers to implement remediation actions as to reduce P loss to sensitive waterbodies.

Deformation monitoring and failure mode research of mining-induced Jianshanying landslide in karst mountain area, China with ALOS/PALSAR-2 images

The Jianshanying landslide in Guizhou province, China, is a typical mining-induced landslide with its complex formation in karst mountainous area. However, the spatiotemporal deformation characteristics and failure mechanism are still unknown. In this paper, the surface deformation time series from 2017 to 2020 is firstly estimated by combining multi-temporal synthetic aperture radar (SAR) interferometry and improved offset-tracking methods to overcome the difficulties caused by the large gradient surface deformation and surface material changes. Then, the spatiotemporal characteristics of Jianshanying landslide is analyzed in terms of line-of-sight (LOS) deformation with stacking InSAR method and two-dimensional (2D) deformation with improved SAR offset-tracking method. And the different deformation features between sliding body and surrounding areas are uncovered. Accordingly, we point out the “three-section” surface deformation model. We further analyze the deformation time series by considering the joint effects of rainfall and underground mining. Finally, we conceptualize the landslide failure mode for the Jianshanying landslide, which can be extended to the similar landslide in karst mountainous areas of southwestern China.

Extraction method for single Zanthoxylum bungeanum in karst mountain area based on unmanned aerial vehicle visible-light images

The efficient and rapid extraction of information about the growth period of the Zanthoxylum bungeanum maxim is one of the prerequisites for analyzing and mastering its growth trend. The 5-cm high-resolution visible-light red, green, blue (RGB) image of the Zanthoxylum bungeanum growing period is obtained based on the low-altitude aerial photography of a quad-rotor unmanned aerial vehicle (UAV) platform. The color space of the R-, G-, and B-channels is converted into the H-, S-, L-, and V-components, and the sensitivity of seven feature vectors to target features is analyzed. The combination of the R-band, H-component, and S-component (which distinguish ground objects very differently) is obtained as the identification feature. Motivated by this, the color space index (CSI) is built by three sensitive component features, which are segmented by the maximum class variance method (OTSU), filtered by majority filtering analysis, and processed by clump to obtain spots containing only the plants. The number of single plants completely separated was calculated by ArcGIS10.2 software, and the average area of a single plant was obtained. The number of conjoined plants was obtained by dividing the cluster by the average area of a single plant. The number of separated complete plants and cluster divisions is counted to get the final total amount of plants and compared with the excess green mainstream index (EXG), visible-light band difference vegetation index (VDVI), and normalized green red difference index (NGRDI). The results indicate the following: (1) the reflectance overlapping phenomenon between ground objects is usually encountered during the construction of the index using only the RGB channel features of the visible-light band. However, the H-, S-, L-, and V-components are merged when the original image features are changed by the color space, in which the images containing only the RGB band are enriched and more conducive to finding sensitive features to distinguish between features; (2) in the CSI extraction results of three experimental research areas and one test verification area, the overall accuracy exceeded 90% (kappa index over 0.90), the false extraction rate and leakage extraction rate were <10 % , and the results showed that the CSI had an effect on the identification and extraction of Zanthoxylum bungeanum; and (3) when the growth environment of Zanthoxylum bungeanum is disturbed by weeds, the CSI has more advantages than the EXG and VDVI.

Spatio-Temporal Differentiation of Trade-Offs and Synergies of Ecosystem Services in Typical Mountain Areas of China

Mountain area accounts for a high proportion of the land area in China, and it is the focal area to solve the contradiction of imbalanced regional development, as well as an important source of ecosystem services. Therefore, this area has been facing long-term pressure and challenges in economic development and ecological protection. In this paper, we selected a rocky desertification mountain area, an active mountain area of new tectonic movement and a typical northern earth-rock mountain area, as Qian-Gui karst Mountain area, Hengduan Mountain area and Taihang Mountain area, as examples to represent three main types of mountain areas. Three representative types of ecosystem services, including NPP (Net Primary Productivity) as a support service, water conservation as a regulation service, and agricultural produce as a supply service, were incorporated into this study. Linear regression, correlation analysis and other methods were then used to investigate the spatial-temporal characteristics of the trade-offs and synergies in each of the three kinds of mountain areas during 1990-2015 in China. The analysis yielded three main conclusions for the three mountainous areas. (1) The agricultural produce supply service decreased relatively, while the support and regulation services of NPP and hydrological regulation increased significantly. (2) There was a synergistic relationship between NPP and the hydrological regulation services in the three mountainous areas. The synergistic relation in Qian-Gui karst Mountain area became enhanced, while those in Hengduan and Taihang Mountain areas became weakened, and the former was weakened to a greater extent. There was a trade-off between NPP, the hydrological regulation service and the agricultural produce supply service among the three mountainous areas. In particular, the trade-off between NPP and the agricultural produce supply service in Qian-Gui karst Mountain area became weaker, while those in Hengduan and Taihang Mountain areas were enhanced, and the latter was enhanced to a greater degree. (3) Significant spatial differentiation was evident in the trade-offs and synergies of ecosystem services among the three mountain areas.

Contribution analysis on spatial tradeoff/synergy of Karst soil conservation and water retention for various geomorphological types: Geographical detector application

Rocky desertification is the most typical ecological and environmental problem in Karst mountainous areas, which hinders sustainable development. Clarifying spatial relationship of ecosystem services including soil conservation and water retention and their dominant factors can provide scientific basis for containment of rocky desertification. The spatialization and quantification of dominant, interaction and sensitive factors affecting synergistic relationships between sediment yield and surface/slope runoff, water yield and slope runoff would be achieved in diverse geomorphological types. Geographically Weighted Regression (GWR) was used to quantitatively analyze spatial relationships between ecosystem services and variables using Soil and Water Assessment Tool (SWAT). Dominant, interaction and sensitive factors were quantitative identification based on Geographical Detector which can accurately reveal the driving factors and their explanatory power through stratification heterogeneity. Precipitation was dominant factor of synergistic relationship between sediment yield and surface/slope runoff, water yield and slope runoff, especially its explanatory power up to 55% in middle elevation plain, middle elevation hill, small relief mountain, and middle relief mountain. Precipitation is the driving force for the runoff and sediment yield occurrence, which was the important factor affecting the ecosystem service synergetic relationship variables. In middle elevation terrace, elevation dominated synergistic relationship between sediment yield and surface/slope runoff. Land use had different explanatory powers to the synergetic relationships of ecosystem service variables, due to diverse land coverages and impervious areas. As for synergistic relationship between sediment yield and slope runoff, the explanatory power of land use types declined with increase in relief degree of landform in mountainous areas. However, it was not related to relief degree of landform between sediment yield and surface runoff, water yield and slope runoff. Land use types, which are mostly determined by human activities, affect the soil erosion and water cycling processes. Besides, lithology types proved to be the sensitive factor because geological conditions are the background of soil erosion and also the important factor affecting runoff. Furthermore, multi-factor interaction significantly increased explanatory power of synergistic relationship. Moreover, their dominating power varied significantly with relief degree of landform, and these findings should be essential for rocky desertification containment.