Karst Rocky Desertification Area Research Articles

Biomass Allocation, Root Spatial Distribution, and the Physiological Response of Dalbergia odorifera Seedlings in Simulated Shallow Karst Fissure-Soil Conditions

Karst rocky desertification (KRD) is a typical fragile ecological environment with its key and difficult management point being vegetation restoration. Therefore, it is crucial to determine the adaptation mechanisms of suitable plants for ecological restoration in KRD areas. D. odorifera is a tall leguminous, woody plant with high medicinal and wood value. This study aimed to explore the adaptation strategy of the D. odorifera root system to the shallow karst fissure-soil (SKF-S) habitats. The growth, biomass, spatial root distribution, morphological characteristics, and physiological responses of D. odorifera seedlings under different treatments were studied in pots simulating SKF-S habitats. Through the experiments conducted, the following conclusions were obtained: (I) D. odorifera enhanced its ability to acquire limited resources through an allocation adjustment strategy (adjusting the biomass allocation strategy, increasing the root shoot ratio, prioritizing organ leaves and 3-level roots), which effectively offset some of the adverse effects; (II) with an increase in the stress severity, D. odorifera improved its resource acquisition adaptive strategy by reducing the root diameter and increasing the contact area with soil; (III) the spatial development characteristics of its root system were mainly manifested in the ability to grow vertically, deeper, compared to a horizontal extension; (IV) D. odorifera did not passively endure rocky desertification stress but actively improved its metabolism through root metabolic activity and SOD enzyme activity.

Role of the preferential flow at rock–soil interface in the water leaking process in near-surface fissures filled with soils in the karst rock desertification area

Soil preferential flow infiltrating rapidly through the rock–soil interface is an important hydrological process in karst rocky desertification area. However, how does the water leakage in the near-surface fissures, especially those filled with soil, proceed? The role of preferential flow at rock–soil interface of those fissures on water leakage process still puzzles us. The goal of this study was to reveal the role of soil preferential flow at the rock–soil interface in the process of water leaking of near-surface fissures. Five typical types of near-surface fissures were selected in an area experiencing severe rocky desertification in Guizhou Province, China. Dye tracer testing was applied, combined with digital image processing techniques. The results indicated that the rock–soil interface flow on both sides of the fissures is the most important preferential flow form in the fissures in karst area. The dyed area ratio of preferential flow varied from 0.12 to 0.48 in the rock + soil profiles, from 0.06 to 0.37 in the soil profiles, and between 0.02 and 0.16 in the rock–soil interface. The rock–soil interface is the smallest in terms of both their variation range of dyed area ratio and preferential flow patterns compared with soil and rock–soil profiles. The soil preferential flow in near-surface fissures mainly occurs in the soil depth range of 0–20 cm. The preferential flow path is mainly affected by the rock–soil interface on both sides and can pass through the clay layer with poor permeability. However, the soil depth of the dyed part was more than 50 cm. The soil preferential flow at the rock–soil interface is the main form of rapid downward leakage of water in near-surface fissures in the karst rocky desertification area, which can flow to the bottom of clay layer with poor permeability.

Effect of Cultivated Pastures on Soil Bacterial Communities in the Karst Rocky Desertification Area.

Soil bacteria play an important role in regulating the process of vegetation restoration in karst ecosystems. However, the effects of vegetation restoration for different cultivated pastures on soil bacterial communities in the karst rocky desertification regions remain unclear. Therefore, we hypothesized that mixed pasture is the most effective for soil bacterial communities among different vegetation restorations. In this study, we systematically studied the soil properties and soil bacterial communities in four vegetation restoration modes [i.e., Dactylis glomerata pasture (DG), Lolium perenne pasture (LP), Lolium perenne + Trifolium repens mixed pasture (LT), and natural grassland (NG)] by using 16S rDNA Illumina sequencing, combined with six soil indicators and data models. We found that the vegetation restoration of cultivated pastures can improve the soil nutrient content compared with the natural grassland, especially LT treatment. LT treatment significantly increased the MBC content and Shannon index. The vegetation restoration of cultivated pastures significantly increased the relative abundance of Proteobacteria, but LT treatment significantly decreased the relative abundance of Acidobacteria. Soil pH and MBC significantly correlated with the alpha diversity of soil bacterial. Soil pH and SOC were the main factors that can affect the soil bacterial community. FAPROTAX analysis showed LT treatment significantly decreased the relative abundance of aerobic chemoheterotrophs. The results showed that the bacterial communities were highly beneficial to soil restoration in the LT treatment, and it confirmed our hypothesis. This finding provides a scientific reference for the restoration of degraded ecosystems in karst rocky desertification areas.

Dynamics of landscape ecological quality based on benefit evaluation coupled with the rocky desertification control in South China Karst

Human uncontrolled land use is the main cause of ecosystem degradation and increased rock desertification in karst areas of Southern China. Landscape ecological quality assessment (LEQA) based on land use plays a significant role in promoting sustainable ecological restoration in karst rocky desertification areas. This paper selects the karst plateau canyon rocky desertification comprehensive control demonstration area in South China as the research object to accurately quantify the impact of ecological management on landscape ecological quality changes (LEQ). Based on the characteristics of the karst ecological environment, the basic theory of spatial heterogeneity and landscape pattern is applied to evaluate the ecological quality of the study area at three levels: landscape stability, landscape disturbance degree, and ecological restoration and reconstruction ability. The results showed that the comprehensive score of regional ecological quality increased from 0.539 to 0.662 from 2015-2020. However, the ecological quality level of unused land and mining areas was still poor, and unsound production activities such as ore mining were the main hindrances to improvements in landscape ecological quality. Areas of better ecological quality were mainly distributed to the north and south of the study area. Treatment measures such as returning farmland to forest and agroforestry effectively improved the ecological environment quality of these areas, but the ecological benefits brought by the treatment in different areas varied significantly. The current analysis results show that the land use-based landscape ecological quality evaluation method is applicable in karst areas with special ecological environments. This work provides a new quantitative research method for the unique ecological environment in karst areas; it can accurately identify trends in ecological environment quality changes and provide a basis for sustainable ecological restoration.

Changes in the Soil Labile Organic Carbon Fractions following Bedrock Exposure Rate in a Karst Context

Soil labile organic carbon fractions (SLOCFs) mainly include microbial biomass carbon (MBC), dissolved organic carbon (DOC), easily oxidized organic carbon (EOC) and light fraction organic carbon (LFOC). The link between bedrock exposure rates with SLOCFs and the carbon pool management index under karst rocky desertification has not been well understood. We selected the bedrock exposure rate and vegetation coverage of 30–50% (light bedrock exposure, LBE), 50–70% (moderate bedrock exposure, MBE) and >70% (intense bedrock exposure, IBE) as the experimental sample plots according to the classification standard of karst rocky desertification, and then selected a sample plot of 0–30% (secondary forest, SF) as the control. This study compared the concentrations and stocks of soil organic carbon (SOC) and SLOCFs and analyzed the relevant carbon pool management index on karst landforms at Anshun, S.W. China. The aims were to determine the relationship between bedrock exposure rates and SLOCFs and to identify the most limiting factors for SLOCFs in karst rocky desertification areas. We found that (1) the concentrations and stocks of SLOCFs declined with increasing soil depth. SOC, DOC and MBC showed IBE > LBE > MBE > SF; LFOC decreased with increasing bedrock exposure rate, and EOC did not show obvious regularity. (2) The carbon pool management index and sensitivity index had significant differences under different bedrock exposure rates. Redundancy analysis and linear regression showed that the increase in bedrock exposure rate had a great impact on MBC, DOC, EOC and SOC. In conclusion, the increase of bedrock exposure rate has no side impact on the DOC, EOC and MBC of the soil, but side effects are exhibited by LFOC. Secondary forest improves the integrity of karst landscapes, and does not change the soil properties as well as the concentrations and stocks of SLOCFs in karst rocky desertification areas.

Revitalization mechanism of specialty industries in the karst rocky desertification areas: From a perspective of the actor‐network theory

AbstractDespite the considerable constraints of karst rocky desertification on the production and life of the locals and the regional economy, few studies have been conducted on areas with karst rocky desertification with the aim of exploring the balance between ecological governance and industrial development. In light of the promotion of featured advantageous industries to ecological governance and industrial development, this study aims to explore the mechanism of industrial revitalization in areas with karst rocky desertification to provide theoretical support for their industrial revitalization. Based on actor‐network theory, this paper presents a case study of Bashan village, a typical area in Guizhou province, China, with karst rocky desertification, to clarify the course of development of itsZanthoxylum bungeanumindustry and propose a mechanism for its revitalization. The findings identify the main actors of the revitalization of theZ. bungeanumindustry and reveal the driving forces behind it. Moreover, the study found that the industrial revitalization model is a bottom‐up process, which suggests strong endogenous dynamics. Through the revitalization of the featured industries, the results of the management of rocky desertification are transformed into economic output, which improved the livelihood of farmers and consolidated the effectiveness of management.

Change in Afforestation-Induced Soil Properties Affects Soil Bacterial Community Composition in Karst Rocky Desertification Area

Change in Afforestation-Induced Soil Properties Affects Soil Bacterial Community Composition in Karst Rocky Desertification Area

Structural evolution of soil aggregates in a karst rocky desertification area.

Desertification and karst landforms are widespread in the water source area of the middle route project of south-to-north water diversion in China. Soil erosion processes directly influence water quality in the water source area and contribute sediments to the bottom of the water reservoir. This study investigates soil evolution over time by sampling a slope surface and discusses associated changes in soil structure, physical and chemical properties, and mineral associations. Changes in soil aggregate structures with slope surface direction and mineral association evolution are observed. The compositions of the main soil minerals and elements are determined using scanning electron microscopy, and X-ray energy spectrum and X-ray diffraction analyses. The results reveal that (1) the evolution of soil aggregates is consistent with evolutionary trends in soil elements and mineral associations. (2) The ultra-microstructure of soil aggregate indicates the soil development stage and condition, while mineral associations indicate the soil development stage along the soil chronosequence. This study increases the understanding of land surface processes in the study area and the soil development, forming and biogeochemical processes in karst rocky desertification areas.

Research Progress on Illicium difengpi (Illiciaceae): A Review

Illicium difengpi K.I.B. et K.I.M. is a member of the Illiciaceae family with a yet not fully explored utilization value. To provide references for the systematic understanding of I. difengpi (Illiciaceae), the morphological and structural characteristics, wild resource distribution, chemical compounds, pharmacological effects, utilization, and protective measures of this species are reviewed. We conclude that (i) I. difengpi (Illiciaceae) is an endemic and indigenous medicinal species that has been used to treat rheumatoid arthritis and traumatic injury in China; (ii) I. difengpi (Illiciaceae) can endure various abiotic stresses, especially extreme drought, and thus has scientific value for exploring adaptive mechanisms of tolerance to extreme drought and in the ecological restoration of karst rocky desertification areas; and (iii) the beautiful tree shapes of I. difengpi (Illiciaceae) give it potential ornamental value. However, the wild resources of I. difengpi (Illiciaceae) have rapidly decreased, and there is an urgent need to protect this endangered species to maintain its diversity. Protection measures include the protection of wild germplasm resources, the establishment of an I. difengpi (Illiciaceae) germplasm resource bank, and the development of large-scale ecological planting techniques. In further research, the medicinal and scientific value of I. difengpi (Illiciaceae) should be systematically explored to clarify the plant’s effective pharmaceutical value, clinical applications, mechanisms of drought adaptation, and genetic diversity.

Epikarst shallow fissure soil systems are key to eliminating karst drought limitations in the karst rocky desertification area of SW China

AbstractSurface soil water shortages are among the primary factors limiting revegetation in most degraded regions with shallow soil, especially in karst areas. Finding water sources for plants is an urgent task to ensure maximum vegetation restoration in these areas. We combined soil water content monitoring and isotope tracing to reveal the principal water source supply systems for plants in karst areas. The results showed that the content and storage of water in the shallow fissure soil system (SFSS) of the epikarst zone were consistently higher and more temporally stable than that of the surface soil. Thus, epikarsts with dissolution voids and fissures are important, stable aquifers that provide water to plants. Moreover, the IsoSource results showed that the SFSS was the primary water source for three monitored tree species (Cupressus torulosa D. Don, Pyracantha fortuneana [Maxim.] Li and Rosa cymosa Tratt.), especially C. torulosa and P. fortuneana. The water‐uptake patterns of C. torulosa and P. fortuneana changed from dominant SFSS and surface soil water sources during the rainy period to the dominant SFSS and transfer zone (TZ) of vadose zone water sources during the dry period. In contrast, Rhynchospora cymosa uses water from SFSS and TZ water sources only during drought. These results suggest that the SFSS is key to eliminating vegetation restoration limitations due to surface drought in karst areas. It is proposed that deeply rooted plants with dimorphic root systems are optimal for sustainable vegetation restoration in karst areas.

Soil quality assessment via the factor analysis of karst rocky desertification areas in Hunan, China

AbstractQuantitative evaluation of soil quality (SQ) is of paramount importance to provide a basis for restoring degraded land that affects the living conditions of people in these degraded areas. Amongst land degradation types, karst rocky desertification (KRD) is caused by human disturbance on a fragile karst geo‐ecological environment. However, SQ evaluations have not been widely and correctly used in KRD soil systems due to the complex soil conditions and lack of uniform standards. SQ evaluation can be qualitatively and quantitatively calculated. Soil quality index (SQI) can be used more frequently due to its simplicity and quantitative flexibility. To quantitatively analyse the SQ of four KRD grades in Hunan Province in China, 25 soil properties at 0–20 cm were identified as potential SQ indicators. SQ was assessed via SQI based on a total data set (TDS) and a minimum data set (MDS). Similar to grey relational analysis (GRA), the SQI was ranked as follows: potential KRD>moderate KRD>light KRD>intensive KRD. Total phosphorus, pH, calcium, clay, capillary porosity, biomass nitrogen and microbial biomass phosphorus were selected into the MDS, and they were sensitive to SQ. However, available phosphorus and soil organic carbon were not selected in the MDS. Soil quality in KRD areas could be quantitatively evaluated using SQI via factor analysis. SQ assessment based on the MDS can represent TDS to reduce labour intensity and detection costs. The quantification of SQ under different KRD grades can provide reference for improving SQ in limestone rocky desertification areas.

Karst rocky desertification diverged the soil residing and the active ectomycorrhizal fungal communities thereby fostering distinctive extramatrical mycelia

Ectomycorrhizal fungi (EMF) are mutualists that play crucial roles in liberation, nutrient acquisition, transfer of growth-limiting resources and provision of water to host plants in terrestrial ecosystems, particularly in stressed prone climates. In this study, a field-based experiment was performed in Yunnan, China to assess the effect of karst rocky desertification (KRD) and natural forests (non-KRD) sites on the richness and composition of EMF communities. Inert sand-filled mesh bags were employed to characterize the active EMF and quantify the production of extramatrical mycelium (EMM). Results indicated that, EMF exhibited a significant differentiation among KRD and non-KRD sites, richness and diversity were higher across KRD areas, whereas the evenness showed the opposite trend. Ascomycota and Zygomycota were greater across KRD sites, however, Basidiomycota showed no difference across both study sites. The relative abundance of Clavaria, Butyriboletus, Odontia, Phyloporus, Helvella, Russula and Tomentella were higher across the KRD sites, whereas, Clavulinopsis, Endogone, Amanita, Inocybe and Clavulina were higher across the non-KRD sites. It's worth noting that, saprophytic (SAP) fungal community was found to be more abundant in the soil than the mesh bags at both sites particularly at KRD sites, which likely provide more free space and less competition for the EMF to thrive well in the mesh bags. In similar pattern, ergosterol concentration in mesh bags was observed relatively higher at KRD sites than the non-KRD sites. The Entoloma, Amanita, and Sebacina were found to be substantially higher in mesh bags than soil across both sites. Delicatula, Helvella and Tomentella on the other hand, showed higher relative abundance in mesh bags than soil over KRD sites, however they did not differ across non-KRD sites. Taken together, the presented results highlight relationship between the EMF community and the complex KRD environment, which is very important for the restoration of disturbed karst landscapes.

Drivers of soil erosion and subsurface loss by soil leakage during karst rocky desertification in SW China

As an extreme manifestation of environmental degradation, karst rock desertification is caused by soil loss and rock exposure. In some areas with serious rocky desertification, there is no soil to be eroded or leaked. The soil loss in these areas superimposes soil erosion and unique subsurface loss by soil leakage through fissures, pipelines, sinkholes, etc., which directly reduce soil resources and accelerate rocky desertification. However, the factors driving soil erosion and subsurface loss by soil leakage are still unclear. Rainfall experiments were conducted on simulated slopes with surface-exposed bedrock and subsurface fissures based on field investigations in a karst rocky desertification area of Guizhou Province, China. Four factors, including rainfall intensity, slope gradient, bedrock exposure rate and subsurface fissure degree, were considered in the experiment. We found that the amount of soil surface erosion and subsurface leakage loss is driven not only by the runoff volume but also by other influential factors. Rainfall intensity is the driving factor determining the amount of surface erosion and subsurface leakage loss of soil and water and the relationship between them. The slope gradient plays a leading role only in subsurface fissure flow leakage loss. The bedrock exposure rate drives the surface soil erosion rate, shows a critical value (30%), and dominates the fissure flow leakage loss rate. Subsurface fissure density plays an important role in the surface loss of soil and water; however, an increase in the subsurface fissure density does not obviously accelerate the subsurface leakage loss of soil and water. Although this result, obtained from laboratory simulations, may differ at the field scale or larger, it could provide a foundation for systematic studies on soil erosion/leakage and insights into the relations between rocky desertification and soil erosion/leakage and their driving factors in karst rocky desertification.

Ecological stoichiometric characteristics of soil-moss C, N, and P in restoration stages of karst rocky desertification.

Rocky desertification is the most serious ecological disaster in karst areas. Comprehensive control of rocky desertification plays an important role in promoting the economic development of karst areas. Studying the stoichiometric characteristics of mosses and soil can provide a powerful reference for the ecological restoration and evaluation of ecosystems experiencing rocky desertification. Soil and mosses were collected from sites representing different stages of ecological restoration (bare rock, grassland, shrubland, and secondary forest), and the contents of carbon (C), nitrogen (N), and phosphorus (P) were detected for ecological stoichiometric analysis. The results indicate that in different restoration stages following karst rocky desertification, the contents of soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) and the stoichiometric ratios in the shrub habitat are higher than those in the bare rock, grassland, and secondary forest habitats. However, the TP and available P contents were low at all stages (0.06 g/kg and 0.62 mg/kg, respectively). The N and P contents and stoichiometric ratios in the mosses showed no significant differences among the succession stages. The C contents in the mosses had a significant positive correlation with SOC and TN and TP content, and the P content had a significant positive correlation with the soil available P. However, there was a significant negative correlation between the C: N and C:P ratios of the bryophytes and soil C: N. In summary, during the process of natural restoration of karst rocky desertification areas, SOC and soil TN contents accumulate with each succession stage. Soil nutrients are higher in shrub habitats than in other succession stages. Mosses have a strong effect on improving soil nutrients in rocky desertification areas.

Total nitrogen is the main soil property associated with soil fungal community in karst rocky desertification regions in southwest China

Karst rocky desertification (KRD) is a type of land deterioration, resulting in the degraded soil and a delicate ecosystem. Previous studies focused on the influence of KRD on the animals and plants, the impact of KRD on microorganisms, especially soil fungi remains to be discovered. This study reveals the change in the soil fungal community in response to KRD progression in southwest China. Illumina HiSeq was used to survey the soil fungal community. Results showed that the soil fungal community in the severe KRD (SKRD) was noticeably different from that in other KRD areas. Statistical analyses suggested that soil TN was the primary factor associated with the fungal community, followed by pH. Phylum Ascomycota was significantly abundant in non-degraded soils; whereas Basidiomycota predominated in SKRD. The ratio of Ascomycota/Basidiomycota significantly decreased along with KRD progression, which might be used as an indicator of KRD severity. Phylum Basidiomycota was sensitive to changes in all the soil properties but AP. Genus Sebacina might have the potential to promote vegetation and land restoration in KRD areas. This study fills a gap of knowledge on changes in soil fungal communities in accordance with KRD progression.

Can agricultural biomass energy provide an alternative energy source for karst rocky desertification areas in Southwestern China? investigating Guizhou Province as example.

Karst in southwestern China forms a rocky desertification area with a particularly vulnerable ecological environment. Studying the potential of agricultural available biomass energy in this region is of great significance for the construction of the rural energy industry and ecological environment protection in karst mountains. This study investigated three regions with different degrees of rocky desertification in the karst mountains of southwestern China. The characteristics of rural energy consumption and their impact on the ecology of Karst region were analyzed. Moreover, the total available agricultural biomass energy resources in the study area were estimated via residue to product ratio, ecological returning coefficient, collection coefficient, conversion coefficient, and by-product coefficient. The research results indicate that the fragile karst ecological environment and the over-consumption of fuelwood resources are the most important reasons for the evolution of rocky desertification in this region, which exposes karst rocky desertification areas and increases the risk of rocky desertification. Given abundant agricultural biomass energy reserves in karst regions of southwestern China, promoting biomass energy as an alternative for fuelwood carries great significance for ecological protection of karst regions. This can serve as an important measure to promote ecological restoration in karst rocky desertification areas.

Soil available nitrogen and phosphorus contents and the environmental impact factors across different land use types in typical karst rocky desertification area, Southwest China.

In this study, we collected soil samples from four different land use types (forest land, shrub land, grassland and abandoned land) in Huajiang valley of Guizhou Province, a typical karst rocky desertification area in Southwest China. Correlation analysis and redundancy analysis were used to examine the distribution of available nitrogen (N) and available phosphorus (P) in diffe-rent soil layers from 0 to 30 cm and the relationships between soil environmental factors (soil physical indexes, organic carbon components, electrochemical properties, metal oxides and enzyme activities) and the contents of available N and available P. The results showed that the concentrations of soil total N, total P, available N, available P decreased significantly with the increases of soil depth. The concentrations of soil available N and available P in forest land and shrub land were significantly higher than those in grassland and abandoned land, which were significantly positively correlated with soil organic carbon composition, enzyme activity, surface electrochemical properties and amorphous mental oxide while significantly negatively correlated with soil silt and free metal oxides. Results of the redundancy analysis showed that the environmental factors affecting soil availa-ble N and available P of the four land use types were basically the same, with soil particulate organic carbon, total organic carbon and soil specific surface area playing a key role in driving the variations of soil available N and available P. The efficient explanation of variation to soil available N and P contents by soil particulate organic carbon might be due to the reduction of soil nutrient loss by the storage of N and P in organic matter. Except for high enzyme activity and electrochemical properties of forest land and shrub land, the higher soil available N and available P concentrations compared with grassland and abandoned land might be resulted from the inhibition of free iron and aluminum oxides information by higher soil organic carbon content and the reduced adsorption and fixation of N and P by iron and aluminum oxides.

Different responses of ecohydrological processes in the re-vegetation area between the dip and anti-dip slope in a karst rocky desertification area in southwestern China

Rocky desertification is an economic, social, and environmental problem, which refers to the processes and human activities that transform a karst area covered by vegetation and soil into a rocky landscape. The effects of different types of soil cover on ecohydrological processes during the revegetation of areas undergoing karst rocky desertification remain unclear. Taking different measures for different ecohydrological situations will benefit re-vegetation in karst rocky desertification areas. Monthly/heavy rainfall hydrochemical data and the δ13C of dissolved inorganic carbon (DIC) in karst water samples from January 2017 to December 2019 were obtained. This revealed the controlling mechanisms on hydrochemical processes by δ13CDIC under different soil cover conditions in the dip/anti-dip slopes of a karst trough valley in Ganxi Town, Chongqing City, southwestern China. Hydrochemical variations are controlled by climate, soil, and vegetation and show clear seasonality. The δ13CDIC values (−16.88‰ to −3.49‰) in the study area were higher than the theoretical value (−14.00‰). In addition, it was observed that rain accelerated soil erosion (R2=0.7) in the karst trough valley and human activities (exogenous acid) resulted in DIC loss. The slopes, soil, and bare rock cover on the dip slope were different from that on the anti-dip slope, leading to the difference in their re-vegetation statuses. In this study, we found that different vegetation restoration schemes and treatment measures should be implemented between the dip and anti-dip slope. The protection of soil and water resources, especially soil, is the key to ecological restoration in rocky desertification areas.

喀斯特石漠化区生态保护红线划定——以贵州省威宁县为例

科学划定喀斯特石漠化区生态保护红线，对于维护区域生态安全，促进经济社会可持续发展具有重要意义。选择水源涵养、水土保持、生物多样性维护3种生态系统服务功能以及水土流失、石漠化2种生态环境敏感性指标，构建喀斯特石漠化区生态保护红线划定方法。以贵州省威宁县为例，结合第二次全国土地调查数据和相关规划等数据，划定生态保护红线，并从生态用地、植被覆盖度与人类扰动指数三个方面评价划定效果。结果表明：（1）威宁县生态系统综合服务功能以极重要为主，占研究区总面积的40.57%。生态环境综合敏感性以敏感为主，占总面积的67.86%。优化调整后生态保护红线面积1496.13 km²，占全县面积的23.75%，红线内生态用地面积占比高于非生态用地面积占比20%以上。（2）近些年贵州省退耕还林、岩溶地区石漠化综合治理和草海自然保护区生态修复等工程的实施，威宁县植被覆盖显著增加，红线内NDVI基本不变区、轻微改善区和明显改善区面积占比达到88.42%，红线范围内植被覆盖呈增加趋势。（3）红线内人类扰动指数低于红线外人类扰动指数，雪山镇、麻乍镇需控制红线范围内人类扰动，确保生态用地性质不改变，加强生态保护和监管。威宁县生态保护红线划定研究可为其他石漠化地区红线划定及划定效果评价提供参考。;It's of great significance to scientifically delineate the ecological conservation redline (ECR) in karst rocky desertification areas for maintaining regionally ecological security, promoting sustainable economic and social development. Three kinds of ecosystem services such as water retention, soil conservation, and biodiversity conservation, as well as two kinds of ecological environment sensitivity indicators (soil loss and rocky desertification) were selected to construct an ECR delineation method for karst rocky desertification areas. Taking the karst rocky desertification area in Weining County of Guizhou Province as an example, combined with the Second National Land Survey data and related planning data, ECR was delineated. We analyzed the evaluation effect from three aspects:ecological land use, vegetation coverage and anthropogenic disturbance index (ADL). Results showed that the comprehensive ecosystem service function was extremely important, accounting for 40.57% of the research area. The comprehensive sensitivity level indicated that the ecological environment was sensitive, accounting for 67.86%. Finally, the area of optimized ECR in Weining County was determined to be 1496.13 km², accounting for 23.75%. The proportion of ecological land in the ECR is 20% higher than that of non-ecological land. In recent years, the implementation of the project of Grain for Green in Guizhou Province, the comprehensive control project of rocky desertification in the karst area of Weining County and the ecological restoration project in Caohai Nature Reserve, vegetation coverage increased significantly. The proportion of normalized difference vegetation index (NDVI) basic constant zone, slightly improved zone and obviously improved zone in the ECR reached 88.42%. It showed that the vegetation coverage is increasing in the ECR. The ADI in the ECR was much lower than the ADI outside the ECR. Xueshan Town and Mazha Town of Weining County need to control the ADI in the ECR, ensure that the property of ecological land within the ECR does not change, and strengthen ecological protection and supervision. The delineation of the ECR in Weining County can provide reference for the delineation and evaluation of the ECR in other rocky desertification areas.

全球主要生态退化区和研究热点区的空间分布与演变

掌握生态退化区和研究热点区的空间分布、退化区生态系统的演变态势是认识生态问题、开展生态治理的基础，但目前缺乏全球主要生态退化区空间分布图等基础数据和相关知识。应用多源数据集成融合、长时序卫星遥感分析、互联网文献大数据建模分析等方法，对以荒漠化、水土流失、石漠化为代表的全球主要生态退化类型区的空间分布、演变态势、研究关注热度等进行了研究。结果表明：（1）全球荒漠化区面积约15.4×10⁶ km²，水土流失区面积约14.3×10⁶ km²，石漠化区面积约1.1×10⁶ km²；这些生态退化区主要分布在非洲撒哈拉沙漠南北边缘，欧洲西部、地中海沿岸、东欧平原南部，南亚印度河流域，中国西北地区、云贵高原，北美洲落基山脉以及南美洲阿根廷等地区。（2）2000年以来，上述退化区中约有3.9%的面积处于退化加重态势，73.3%的面积处于脆弱平衡状态，22.8%的区域出现好转趋势。（3）全球生态退化研究热点区的分布与全球生态退化区的分布总体呈现一致性。但在沙特阿拉伯中部、哈萨克斯坦北部，巴西大部，安哥拉、南非等生态退化区，存在生态系统继续恶化、缺乏研究界足够关注的情况。研究成果深化了对全球主要生态退化区分布格局的认识，对于防范全球发展和建设中出现加重的生态退化等具有参考价值。;Knowing the spatial distribution of ecological degradation regions and research hotspot regions, as well as the evolution of ecosystems in the degradation regions are the basis for understanding ecological problems and ecological environment management. However, there is a lack of basic data and relevant knowledge research in the world. In this paper, multi-source data integration, long-term satellite remote sensing analysis, and the Internet literature big data modeling analysis are applied to study the spatial distribution, evolution trend and the research hotspots of global major ecological degradation, i.e. land desertification, soil erosion and karst rocky desertification. The results show that:(1) the global desertification area is about 15.4×10⁶ km², the soil erosion area is about 14.3×10⁶ km², and the karst rocky desertification area is about 1.1×10⁶ km². The global major ecological degradation regions are mainly distributed in northern and southern margin of the Sahara in Africa, the Mediterranean coast in Western Europe and southern plain of the Eastern European, the Indus River Basin in South Asia, the Northwestern China and the Yunnan-Guizhou Plateau of China, the Rocky Mountains in North America and Argentina in South America. (2) Since 2000, about 3.9% of the above degraded areas have been deteriorating, 73.3% of them were still in a fragile dynamic balance state, and 22.8% of them have been improved. In terms of spatial distribution, the attention of global researchers is generally consistent with that of typical ecological degradation regions. However, there are still some areas where the ecosystems continue to deteriorate, but at the same time they lack sufficiently scientific research attention, on the central Saudi Arabia and Northern Kazakhstan in Asia, Brazil in South America, Angola and South Africa in southern Africa, etc. The research results deepen people's understanding of the distribution pattern of global major ecological degradation regions, and have reference value for preventing the aggravated ecological degradation in the developments and engineering construction worldwide.