Impact of Vegetation Restoration on Soil Fungal Community Structure in Karst Rocky Desertification Areas

In this paper,managed forest(MF)and natural forest(NF)in the Huajiang Demonstration Zone of Guanling,Guizhou were selected as research objects,and cropland(CL)was taken as control.High-throughput sequencing technology was used to study the characteristics of fungal community composition and species diversity in the surface(0-10 cm)soil of each restoration measure,in order to reveal the dominant soil fungal groups and fungal community composition in karst rocky desertification areas,which was conducive to a more comprehensive understanding of the soil conditions of different vegetation restoration measures.Research has shown that vegetation restoration significantly affected the diversity of soil fungal community,with significant increases in Sob index,Ace index,and Chao index.The vegetation restoration has significantly changed the composition of fungal community.The dominant fungi in the CL topsoil are Sordariomycetes(62.28%),Dothideomycetes(12.34%),and Eurotiomycetes(9.12%);the dominant fungi in the MF soil are Sordariomycetes(45.05%),Dothideomycetes(14.74%),and Mortierellomycetes(10.40%);the dominant fungi in the NF soil are unclassified fungal community(26.38%),Sordariomycetes(19.78%),and Agaricomycetes(13.82%).Vegetation restoration has changed the key fungal groups in the soil.Sordariomycetes,Fusarium,and Setophoma are the key dominant fungal groups in CL soil;Dioszegia is key dominant fungal group in MF soil;c_unclassified_k_Fungi,p_unclassified_k_Fungi,o_unclassified_k_Fungi,f_unclassified_k_Fungi,g_unclassified_k_Fungi,Teichospora,and Diaporthe are key dominant fungal groups in NF soil.

Rocky Desertification Dynamic Analysis and the Development of Management Information System

With the background of severe rocky desertification in the west of China and the ohjective of ecological environment construction and poverty elimination, the management information system of rocky desertification was designed according to the natural and humane characteristics in Nanchuan of Sichuan Province. The system was composed of data management module, information query module for rocky desertification, spatial analysis module and dynamic monitoring module.

Rocky Desertification Risk Zone Delineation in Karst Plateau Area:A Case Study in Puding County,Guizhou Province

Karst rocky desertification is a geo-ecological problem in Southwest China. The rocky desertification risk zone delineation could be used as a guide for the regional and hierarchical rocky desertification management and prevention. We chose the middle and lower reaches of the Houzhai underground basin on the karst plateau in Puding County, Guizhou Province, China as the study area and selected land use type, elevation, slope, aspect, lithology and settlement buffer as the main driving factors of the rocky desertification. The potential risk of rocky desertification was quantifed with the factor-weights union method and statistical analysis method. Five grades of rocky desertification risk were delineated based on Geographic Information System. The extremely low, low, moderate, high and extremely high rocky desertification risk zones accounted for 5.01%, 44.17%, 33.92%, 15.59% and 1.30%, respectively. As a whole, the rocky desertification risk level was moderate because the area of low and moderate rocky desertification risk zones occupied 78.09% of the study area. However, more than half of the area （about 50.81%） was predicted to have moderate rocky desertification risk and above, indicating that the study area was subject to rocky desertification. Rocky desertification risk was higher in the southeast and lower in the northwest of the study area. Distinct differences in the distribution of rocky desertification risk zones corresponding to different factors have been found.

Research of Ecological Restoration of Mycorrhizal Mulberry in Karst Rocky Desertification Area

Mycorrhizal mulberry is a plant, whose mulberry root and Arbuscular Myc-orrhizal fungi came into being a symbiotic relationship by a mean of natural or artifi-cial inoculation. Mycorrhizal mulberry coupling with main ecological barriers, such as barren soil drought in rocky desertification area, wil be beneficial to recovering the karst degraded ecosystem by removing these stresses. So, mycorrhizal mulberry is considered a new effective way in ecological control of karst rocky desertification. The research summarized the structures and the characteristic eco-physiological functions of arbuscular mycorrhizal fungi （AMF）, and preliminarily discussed its availability and research in karst rocky desertification restoration ,including investiga-tion of AMF diversity, the key affecting factor of AMF species diversity, the sym-biosis mechanism between AMF and mulberry, promoting the development of agri-cultural economy in Karst Rocky Desertification area by mycorrhizal mulberry. These elaborate efforts are to demonstrate mycorrhizal mulberry adapting to karst environ-ment from a new view, lay a theoretical basis for karst degraded-ecosystem restoration, and final y guarantee sustainable development of mycorrhizal mulberry in rocky desertification area.

Dynamic Change and Simulation and Prediction of the Karst Rocky Desertification Sensitivity in Guizhou Province

Sensitivity evaluation of rocky desertification is to recognize the areas prone to be rock-deserted,so as to assess the sensitivity degree of rocky desertification to human activities.To perform the sensitivity evaluation of rocky desertification,we should be on the basis of the mechanism of rocky desertification formation for analyzing its regional distribution difference in the sensitivity and further for finding out the rocky desertification-susceptive areas and their possible degrees.Employing remote sensing and geological information system techniques,we regarded the 1∶ 50 000 topographic map and the TM image in 2000 of Guizhou Province,together with the hydrologic map,soil map,geologic map,rock formation map,administrative map and other geological information as data sources to generate the degree data of rocky desertification sensitivity of Guizhou Province in 1962 and 2000,based on which we determined the corresponding degree transfer matrix and adopted Markov model to simulate the dynamic change process of rocky desertification sensitivity and its future evolution trend.In various sensitivity types of rocky desertification in Guizhou Province,only the insensitive type showed a declined acreage,from the proportion of total land acreage of 61.35% in 1962 to 55.55% in 2000.Various sensitivity types inter-conversed,resultantly the acreage of mildly sensitive type increased most.The prediction results showed that the acreage of insensitive type of rocky desertification in Guizhou Province will assume a remarkable decline trend,of mildly sensitive type will present a remarkably increasing trend and of slightly sensitive type basically will maintain a stable level in the future tens of years.Acreages of both highly sensitive and extremely sensitive type of rocky desertification expanded to some extent,suggesting that the rocky desertification risk in Guizhou Province is in an aggravating process.

Mine rocky desertification： Another type of rocky desertification coexisting with Karst rocky desertification in Karst region

Mine rocky desertification is another type of rocky desertification which coexists with Karst rocky desertification, suggested firstly by professor SONG Jian-bo, Guizhou University. Mine rocky desertification is a process and result that the earth＇s surface is similar to desert landscapes after rock is exposed gradually, owing to mine wastes discharged at will which consist of waste residue, waste liquid and waste gas. On the basis of introducing Karst rocky desertification simply, we clarify the concept of Mine rocky desertification systemically, analyze its danger and compare the differences between Mine rocky desertification and Karst rocky desertification. Finally, we make preliminary discussion on the study significance of comprehensive treatment of Mine rocky desertification

Human Driving Forces:Analysis of Rocky Desertification in Karst Region in Guanling County,Guizhou Province

Karst rocky desertification is one of the major ecological and environmental problems that threaten the sustainable development of southwestern China. It is caused by irrational and intensive land-use patterns in karst geo-ecological environment. Therefore, it is vital to identify how human forces work on this degraded environment. Based on the soil erosion information in 2000 and remote sensing images of Guanling County collected in 2000 and 2007, four grades of karst rocky desertification data in 14 villages of Guanling County were extracted. Impacts of population, affluence, and other human forces on karst rocky desertification were analyzed using STIRPAT model. The results show that:1) Factors of population and affluence had strong influence on karst rocky desertification. In the STIRPAT model analysis, the population and affluence coefficients were positive, indicating that the increase in population and affluence would lead to more serious desertification. 2) Factors of farmer correlated with karst rocky desertification negatively, especially the way of viewing the relationship between people and nature, and the level of knowledge about rocky desertification. Government behavior was not a significant factor in this analysis. 3) The findings provide evidence that STIRPAT model can be used to analyze the relationship between human driving forces and rocky desertification.

Effects of rainfall and rocky desertification on soil erosion in karst area of Southwest China

Monitoring and evaluating the evolution of rocky desertification timely and studying the characteristics of soil erosion under different rainfall patterns are of great scientific significance for regional soil and water conservation,rocky desertification control and ecological environment construction.Four periods of remote sensing image data from 2005 to 2020 were selected to study the evolution characteristics of rocky desertification and its impact on soil erosion in the controlled boundary area of Shibantang hydrological station of Yeji River Watershed,Guizhou Province,China.According to the 408 erosive rainfall events,the soil erosion under different rainfall patterns in the watershed was analyzed.The results showed that:erosive rainfall events in the study area were mainly pattern A,accounting for 57.4%of the total rainfall events;the second was pattern B,accounting for 28.9%of the total rainfall events;the rainfall pattern of C occurred occasionally.Among them,pattern A was the main rainfall pattern leading to soil and water loss and had the largest contribution rate to soil erosion in the watershed.From 2005 to 2020,the area of rocky desertification showed a decreasing trend,accounting for 72.2%from 87.9%.Spatially,rocky desertification has mainly concentrated in the middle south of the watershed since 2010,while the rocky desertification mainly concentrated in the middle and north before 2010.The effects of different grades of rocky desertification on soil erosion were different,and the soil erosion modulus in areas with the medium,severe and extremely severe rocky desertification was generally small.The soil erosion modulus estimated by the RUSLE(Revised Universal Soil Loss Equation)model was still much higher than that calculated by the data measured by the hydrological monitoring station.Therefore,the application of the RUSLE model in karst area needs to be further modified.These results can provide reference for rocky desertification control,soil erosion control and fragile ecosystem restoration in karst area.

Characteristics of Changes in Karst Rocky Desertification in Southtern and Western China and Driving Mechanisms

The karst landform is a typical ecologically vulnerable region,and the problem of karst rocky desertification in southtern and western China has led to impoverishment and a degraded local ecological environment,which severely limits local socioeconomic development.An effective and appropriate control of karst rocky desertification in southtern and western China requires knowledge about its characteristics of variation and driving mechanisms.In this study,we chose eight regions in the southtern and western China as research areas and analysed the characteristics of the changes in karst ecosystem patterns and rocky desertification from 2000 to 2015.Based on these characteristics,we present the mechanisms that drive karst rocky desertification in the southtern and western China by utilizing the redundancy analysis(RDA)ordination method.The results show that the total area of rocky desertification in southtern and western China had been continuously decreasing from 2000 to 2015,revealing a positive development trend in rocky desertification.Rocky desertification variations were mainly affected by human activities.The reduction in farmland area improved farmland management and increased regional gross industrial product,which together with continuously rising gross domestic product of the tertiary industry caused a positive rocky desertification development.However,the local karst tourism has a certain effect on inducing slight rocky desertification.

DESIGN AND APPLICATION OF DYNAMIC MONITORING AND VISUALIZATION MANAGEMENT INFORMATION SYSTEM OF KARST LAND ROCKY DESERTIFICATION

In order to study the spatial-temporal change and environmental management of regional karst LUCC (land use and land cover change) and its causative environmental effect-rocky desertification by integrating qualitative analysis and quantitative analysis, and relying on RS, GIS and GPS (3S) techniques, karst land rocky derification dynamic monitoring and visualization management information system (KLRD.DMVM.IS) is framed, which includes design aim and structure model, function design, database design and model system design. The model system design gives priority to dynamic monitoring, drive force diagnosis, comprehensive evaluation and decision support of karst rocky desertification. From the viewpoint of model type, mathematic expression and its meaning, the dynamic monitoring models are concretely devised to reflect the spatial and temporal changing features and the trend of karst LUCC and rocky desertification. Taking Du'an Yao Autonomic County of Guangxi as an example, the KLRD.DMVM.IS is systematically analyzed in the application of the process and trend of karst LUCC and rocky desertification in Du'an County, and it provides the technical support for the study on karst land rocky desertification.

The causes and processes responsible for rocky desertification in karst areas of southern China

The karst region of southern China is a fragile ecological zone with widespread rocky desertification. This paper describes the rocky desertification occurring in this region in terms of both natural and anthropogenic factors. During geological time periods, the region’s changing environment governed the natural rocky desertification processes, whereas during historical and modern times, anthropogenic processes have been superimposed on these natural processes. Human activities have accelerated and exacerbated rocky desertification. The period from the beginning to the middle of the Qing dynasty was an important transitional period in which human activities began to exert a particularly strong influence on rocky desertification. Since then, the effect of anthropogenic factors has increasingly exceeded the effect of natural factors. The rocky desertification process in southern China’s karst region combines surface ecological processes (including vegetation degradation and loss, soil erosion, surface water loss, and bedrock solution) with a reduction of the land’s biological productivity, leading to degradation that produces rocky desert. Controlling rocky desertification requires comprehensive development of sustainable agriculture and economic development that provides employment alternatives to agriculture and thereby promotes the rehabilitation of rocky desertified land.

Study on the Driving Forces of Rocky Desertification in Guizhou Province Based on Variation Coefficient Method

[Objective] The aim was to study the driving forces of rocky desertification in Guizhou Province. [Method] Based on GIS and RS technology, the main driving forces of rocky desertification in Guizhou Province were analyzed by means of correlation analysis and variation coefficient method, and then the distribution of rocky desertification in Guizhou Province was assessed synthetically. [Result] The main driving forces of rocky desertification in Guizhou Province were vegetation cover, rainfall, peasant income and gradient which were obviously correlative with rocky desertification; from theoretical distribution, rocky desertification was the most serious in Bijie, southwest Guizhou, southern Guizhou and northeastern Guizhou, and the theoretical distribution of rocky desertification in Bijie was severer than its current situation, which showed that construction of ecological function area in Bijie restrained the development of rocky desertification effectively; the good consistency between theoretical and current distribution of rocky desertification revealed that the study method was feasible. [Conclusion] The study could provide theoretical references for the practical control of rocky desertification.

Monitoring of Karst Rocky Desertification Control Projects Based on Remote Sensing Images with Medium and High Spatial Resolution——A Case Study of Disi River Basin in Puan County

[ Objective] The study aimed to improve methods of monitoring Karst Rocky Desertification （KRD） control projects and increase the working efficiency. [Method] Based on remote sensing images with medium and high spatial resolution, KRD control projects in Disi River basin in Puan County were monitored, that is, information of the project construction in the study area was extracted using supervised classification and hu- man-computer interactive interpretation, and the monitoring results were testified with the aid of GPS. [Result] It was feasible to monitor KRD con- trol projects in Disi River basin based on remote sensing images with medium and high resolution, and the monitoring accuracy was satisfactory, reaching above 80% or 90%, so the method is worthy of popularizing. [ Conclusion] Remote sensing images with medium and high resolution can be used to monitor other KRD control Droiects.

Preliminary Study on the Ecological Agriculture Development Model of"Pennisetum sineseRoxb-Rocky Desertification Control-Edible Mushrooms"in Guizhou Province

In Guizhou Province, the area of rocky desertification land is 3.023 8 million hm^2, accounting for 17.16% of total area of land in the province. Rocky desertification is the most important ecological problem that restricts the economic and social development in Guizhou, so the primary task of ecological construction in Guizhou Province is to curb rocky desertification. How to effectively, efficiently and persistently use rocky desertification land is not only the key to the improvement of ecological environment, but also an urgent problem solved for local people's survival and anti-poverty. Due to having developed roots, growing fast, high yield of grass, strong resistance to drought, and high regeneration capacity, Pennisetum sinese Roxb has become a new method to control rocky desertification. How to use P. sinese Roxb efficiently becomes the key to the ecological control of rocky desertification by P. sinese Roxb. In this study, the ecological agriculture development model of "P. sinese Roxb-rocky desertification control-edible mushrooms" was studied, and the effect of cultivating Pleurotus eryngii with P. sinese Roxb in rocky desertification land was analyzed. Moreover, an outlook for the application of P. sinese Roxb in rocky desertification areas of Guizhou was given.

Ecological Restoration of Rocky Desertification in Hongfeng Lake Karst Area Based on SWOT Analysis

In order to provide a reference for rocky desertification control in karst areas,we take the case of Hongfeng Lake Rocky Desertification Comprehensive Control Demonstration Area in Qingzhen City of Guizhou Province,and expound strength,weakness,opportunity and challenge in its ecological restoration,using SWOT analysis method in management sciences.And we finally put forth scientific strategies for ecological restoration in this demonstration area.

DEVELOPMENT AND DESIGN OF A DISASTER INFORMATION SYSTEM ON REGIONAL KARST ROCKY DESERTIFICATION

Based on a systematic analysis about the design principles, systematic objectives, clients’ demands and functional modules of the regional karst desertification disaster information system, a systematic application plan was proposed in this paper that the mainstream technologies like COMGIS, etc. can be used for secondary development, and Du’an Yao Autonomous County of Guangxi was taken as an example to illustrate the application of geographical information system in development of karst desertification disaster information system, and to provide a feasible plan for realization of accessory decision information aiming for sustainable development of karst desertification area.

Physio-ecological adaptability and service function in karst rocky desertification control of Premna puberula

Increased soil erosion as a consequence of karst rocky desertification(KRD)reduces soil quality and plant diversity.Premna puberula Pamp.is a perennial understory shrub that can adapt to the harsh environment of KRD and has potential value for KRD environmental restoration.We measure morphological and photosynthetic characteristics,nutrient accumulation,and soil physical and chemical properties of two-year-old P.puberula planted in KRD habitat and non-rocky desertification areas,and investigate how it adapts to this habitat.In KRD areas,P.puberula reduces aboveground water loss by decreasing leaf area,stomatal conductance,and transpiration rate,while increasing leaf thickness,root length and number,and increases belowground biomass to absorb more water and nutrients.In KRD areas,drought leads to decreased leaf water content,stomatal conductance,intercellular CO_(2) concentration,and chlorophyll content,and decreased photosynthetic rate.Soluble sugar and protein contents increase in KRD areas in response to water stress,but pectin and flavonoid contents decrease.Correlation analysis reveals that leaf area and thickness are important functional traits that affect leaf water content and photosynthesis.Totals of leaf carbon,nitrogen,and phosphorus,along with C:N,C:P,and N:P ratios,are coupled with leaf photosynthetic characteristics and root development.Redundancy analysis reveals that available K and P,and total P,K,and N in soil mainly influence the differences in plant functional traits,explaining 95.8%,95.5%,91.1%,85.8%,and 74%of variation,respectively.We hypothesize that P.puberula reduces aboveground productivity to maintain its water balance,and acquires more water and nutrients by increasing belowground biomass.It indicates that this species adapts to arid KRD environments.

The Value of the Miao People’s Traditional Ecological Knowledge for a Solution to Rocky Desertification in Mashan

There are many branches of the Miao people in China, one of which is the Mashan Miao, who have been living in karst mountainous areas in southwest Guizhou Province. The Mashan Miao have adopted various measures for the conservation and effective utilization of the local ecological system and have made great achievements in this area. From the 1950s, their social environment has changed a lot due to political and economic movements. The rocky desertification in the Mashan area has gradually expanded. After the 1990s, relief work was carried out to address the desertification problem, but it was not very effective. We have been doing fieldwork in this area for more than 20 years and from our fieldwork records, we have found that the local Miao people have traditional ecological knowledge and skills that are of irreplaceable valuable for finding a solution for rocky desertification. Using the Miao knowledge we think a feasible way to control this disaster can be found.

Spatial Distribution Characteristics of Rocky Desertification in Qiandongnan Prefecture of Guizhou Province

Rocky desertification is a serious threat to socioeconomic development and the ecological security of karst areas. The control of rocky desertification has therefore become a major concern of both the Chinese government and local populations living in karst areas. In this paper, we used the national evaluation system for monitoring rocky desertification, and adjusted relevant indices. For example, we improved the system＇s base rock exposure index with Normalized Difference Rock index（NDRI）, substituted a soil erosion index for soil depth, and from these obtained the categories and spatial distribution of rocky desertification. We also studied the main factors and functional mechanisms of rocky desertification with consideration given to natural geographic conditions such as soil, physiognomy, elevation, slope and river network density, and, also human interference factors such as population density, GDP, population distribution, and from these got spatial distribution characteristics and influencing factors of rocky desertification in Qiandongnan prefecture. Results indicate that the primary soil types of rocky desertification in the research areas include yellow, limestone and paddy soils. These rocky desertification areas are more likely to contain limestone soil than purple soil, and least likely to contain paddy soil. The distribution of moderate or severe rocky desertification in areas with moderate to steep slope is 40%, where sloping agricultural land comprises a large proportion of the total. Rocky desertification is widely distributed in regions with precipitation between 1000–1200 mm, and this precipitation is the main factor causing greater soil erosion in limestone soil base and sloping agricultural areas. Moreover, desertification is closely related to the distribution of residential areas, population density, poverty and sloping agricultural land

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.