Rocky Desertification Control Research Articles

Altitude differences impact gene expression and accumulation of main medicinal ingredients of Zanthoxylum planispinum var. Dintanensis in rocky desertification control areas

Abstract Environmental factors such as altitude may significantly influence both the morphological trait and accumulation of metabolite products in plant. In present study, gene expression profiles of Z. planispinum var. Dintanensisin grown at different altitude (A1:1054 m.a.s.l., A2:821 m.a.s.l., A3:645 m.a.s.l.) were generated by using RNA-Seq. Four main medicinal ingredients of peels were determined, including the total acylamide, total flavonoids, total alkaloids and volatile oil content. The results showed that a total of 10,703 differentially expressed genes (DEGs) were identified among the three samples (A1, A2, A3), of these, 315 DEGs were putative transcription factors (TFs) belonging to 74 TF families. In particular, some candidate genes related to accumulation of main medicinal ingredients have been screened through combining Kmeans cluster and KEGG enrichment analysis. Besides, the total flavonoid accumulation exhibited a positive correlation with increasing altitude, suggesting that higher altitudes favor metabolite accumulation. Notably, seven genes and one MYB TF involved in the biosynthesis of the main medicinal ingredients were confirmed through RT-qPCR analysis The data obtained in this study offers a global survey of gene expression patterns of Z. planispinum var. Dintanensis grown in rocky desertification control areas, which support for further research on the high-altitude adaptation mechanism and identification of peels with higher medicinal value.

Effect of Rocky Desertification Control on the Nonlinear Trends of Gross Primary Productivity in Southwest Karst Areas, China

ABSTRACTMonitoring trends in gross primary productivity (GPP) is essential for assessing changes in carbon sinks. The implementation of rocky desertification control in karst areas has led to an increase in GPP. However, its impact on the nonlinearity of GPP increase has not been determined. Based on the ensemble empirical mode decomposition (EEMD) method, this paper analyzed the nonlinear trend of GPP in the Karst region of southwest China from 1982 to 2018 and clarified the impact of rocky desertification control on the nonlinear trend of GPP, the results show that: (1) The Mann–Kendall method found that 47.17% and 50.11% of the study areas showed nonsignificant change and significant increase in GPP, however, 6.72% and 8.58% of the regions with nonsignificant change and significant increase respectively show the trend reversal from increase to decrease with EEMD method, moreover, 2.94% and 4.19% show the trend reversal from decrease to increase, respectively; (2) Rocky desertification control changed GPP more significantly in rock desertification area than nonrocky desertification area. With the aggravation of rocky desertification, the control effect becomes better, which is reflected in the increasing proportion of monotonic increases in GPP. However, for severe rocky desertification areas, the effect of governance is more reflected in the large proportion of GPP from reduction to increase. (3) The control effect is better, but the risk of carbon sink reduction is higher in changed rocky desertification areas than those in unchanged rocky desertification areas. In the meantime, the mitigation of rocky desertification can favor the increasing of GPP in the areas with severe and moderate rocky desertification, while it can just reduce the risk of decreasing of GPP in the areas with potential and slight rocky desertification. Overall, this study enhances our understanding of the impact of rocky desertification control on carbon cycle processes in both changed and unchanged rocky desertification areas.

Vegetation Restoration Patterns Influence the Supply and Interrelations of Grassland Ecosystem Services in Karst Desertification Control

An appropriate vegetation restoration pattern is crucial for maintaining and enhancing ecosystem functions and services in karst rocky desertification control areas. However, it is still unclear whether different vegetation restoration patterns will aggravate the trade-off of grassland ecosystem services in this area. This study focuses on grassland ecosystems in the karst desertification control area, comparing artificial restoration measures (Dactylis glomerata single-species sowing grassland, DG; Lolium perenne single-species sowing grassland, LP; Lolium perenne + Trifolium repens mixed-species sowing grassland, LT) with natural restoration measures (NG). Seven ecosystem services (forage yield, soil retention, soil water conservation, carbon fixation and release, soil carbon storage, soil nutrient retention, and biodiversity conservation) as well as total ecosystem services were quantified using field monitoring data. The relationships between these services were evaluated through Spearman correlation analysis. The results showed that different vegetation restoration patterns significantly influenced the provisioning, regulating, and supporting services of the grassland ecosystem (p < 0.001). Three types of relationships were observed (trade-off, synergy, and neutral), but the trade-off relationship was not significant (p > 0.05). The total ecosystem service of LT (0.79) was significantly higher than that of NG (0.21), DG (0.36), and LP (0.41), with a significant synergy observed between soil nutrient conservation, forage yield, and carbon sequestration and oxygen release (p < 0.05). Therefore, LT is considered the best vegetation restoration practice for the karst rocky desertification control area compared with other patterns. This study provides theoretical guidance for vegetation restoration in degraded karst ecosystems.

The restoration of karst rocky desertification has enhanced the carbon sequestration capacity of the ecosystem in southern China

The control of rocky desertification is the largest ecological restoration project in southwestern China, but its impact on the carbon sequestration capacity of karst ecosystems is not clear. Therefore, in this paper selects typical subtropical karst areas in Guangxi are selected as the research object, the carbon sequestration potential of the terrestrial ecosystems are quantified, including karst inorganic carbon sinks, and the response of the terrestrial ecosystem carbon sink to rocky desertification restorationis discussed. The results show that (1) the karst inorganic carbon sink flux (CCSF) is 42.75 t CO2/km2/yr, with a total CCS of 491.12 × 104 t CO2, accounting for only 2.5 % of the country's land area and contributing 7.6 % of the karst inorganic carbon sink. (2) The flux of the vegetation organic carbon sink is 380.44 t CO2/km2/yr, and the total amount is 4403.55 × 104 t CO2/yr., Overall, the spatial distribution exhibits a pattern of high in the northwest and low in the northeast. (3) With decreasing rocky desertification area, the magnitude of the terrestrial ecosystem carbon sink has exhibited a corresponding increasing trend. In particular, during 2010–2020, the rocky desertification area decreased by about 0.868 × 104 km2, and the terrestrial ecosystem carbon sink increased by 114.04 t CO2/km2/yr. This article provides a systematic spatial diagnosis of the carbon sequestration potential of terrestrial ecosystems, including karst inorganic carbon sinks, in the karst areas of Guangxi, and reveals their responses to the restoration of karst rocky desertification. This work has strong reference value and significance for the diagnosis and analysis of the carbon neutrality capacity at the national and global levels.

Prediction of soil organic matter using Landsat 8 data and machine learning algorithms in typical karst cropland in China

Soil organic matter (SOM) is crucial for karst ecosystems, affecting cropland health, climate change mitigation, and rocky desertification control. However, there are limited research on cropland SOM prediction in karst areas with complex topography and diverse microclimates. Here, we compared the performance of four machine learning algorithms—random forest (RF), support vector regression (SVR), multilayer perceptron regression (MLP), and gradient boosting regression trees (GBRT)—for predicting cropland SOM in a typical karst landform area in 2019. Our results indicated that the GBRT model achieved the highest prediction accuracy with an R² of 0.69, MAE of 2.19 g/kg, RMSE of 3.37 g/kg, and LCCC of 0.82. Using the GBRT model and spatial data on climate, topography, and remote sensing, we predicted SOM for each 30 m × 30 m grid cell. The analysis revealed higher SOM content in the northeastern and southwestern regions and lower content in the central area, ranging from 13.95 to 47.81 g/kg, with an average of 27.16 g/kg. Lime soil had the highest SOM content, while purple soil had the lowest. Paddy fields showed significantly higher SOM than dry land. Over the past 40 years, SOM content has slightly increased, while its spatial distribution has remained stable.

Comprehensive assessment of rocky desertification treatment in Southwest China karst

AbstractRocky desertification is a prominent ecological issue in Southwest China's karst region, ranking among the nation's three primary ecological challenges alongside soil erosion and desertification. The government initiated the Rocky Desertification Treatment Program in 2008, lacking a comprehensive evaluation of its benefits. This study evaluates the program's impact on ecosystem services over the last two decades using remote sensing, ecosystem models, and field data. The results indicated a continuous net decrease of rocky desertification, 48% in the eight southwestern provinces from 2005 to 2021. The average annual growth rate of vegetation cover reached 2.54% in key counties for rocky desertification control, significantly higher than that of all the 451 rocky desertification counties from 2016 to 2020. Additionally, ecosystem productivity increased by 35.8% in rocky desertification counties from 2000 to 2020, which is 1.34 times greater than that observed in non‐rocky desertification counties. It was found that the ecosystem service promotion after the net reduction of rocky desertification area in 2010–2020 is more significant, especially the carbon sequestration in 2010–2020 of key counties for rocky desertification control is 2.7 times than that in 2000–2010. It indicates that the rocky desertification treatment enters the stage of ecosystem service promotion on the basis of achieving rapid “greening,” leading to significant improvements in ecosystem structures and services in the karst region of Southwest China. To mitigate the risk of rocky desertification, tailored measures must be implemented considering local climate, lithology, landform types, and human–land relations for effective treatment zoning and classification.

Remote Sensing Ecological Quality and Its Response to the Rocky Desertification in the World Heritage Karst Sites

Clarifying the spatial and temporal evolution characteristics of the ecological environment quality of World Heritage Karst Sites (WHKSs) and its response to different rocky desertification grades at spatial scales is crucial for the monitoring and protection of WHKSs as well as the implementation of ecological and environmental policies in karst regions. The ecological evaluation model of Remote Sensing Ecological Index (RSEI) was used to evaluate the ecological environment of Libo–Huanjiang World Heritage Karst site and Shibing World Heritage Karst site, and then the spatial autocorrelation and geo-detection model was used to further analyze the ecological environment, and final spatial overlay of RSEI and rocky desertification by year to analyze the linkage relationship between RSEI and rocky desertification. The results showed that (1) in the three-phase ecological environmental quality evaluation of the two heritage sites, the RSEI in 2010, 2016, and 2022 reached 0.60, 0.67, and 0.64 for the Libo–Huanjiang heritage site, and RSEI in 2010, 2016, and 2022 for the Shibing heritage site reached 0.60, 0.74, and 0.70, respectively; (2) the RSEI of both heritage sites show a gradually increasing positive spatial correlation, and has significant spatial aggregation characteristics, with both heritage sites dominated by the high-high and low-low spatial aggregation categories; (3) both heritage sites have the highest degree of explanation of changes in ecological quality by the NDBSI factor, indicating that this factor plays a key role in changes in ecological quality at heritage sites; (4) the response of the RSEI mean value of Libo–Huanjiang in each grade of rocky desertification area is, from high to low, no rocky desertification, non-karst, potential rocky desertification, mild rocky desertification, moderate rocky desertification, intensive rocky desertification, and extreme intensity rocky desertification, and the response of the RSEI mean value of Shibing is, from high to low, non-karst, no rocky desertification, potential rocky desertification, mild rocky desertification, and moderate rocky desertification. The spatial superposition analysis of the RSEI index and rocky desertification index can quantitatively study the changing status of the ecological environment in different rocky desertification areas, and the results of the study can provide theoretical references for the environmental monitoring and the prevention and control of rocky desertification in the karst areas and WHKSs.

Characteristics and influencing factors of farmland abandonment in the karst rocky desertification area of Southwest China

Owing to rocky desertification, farmland abandonment in karst areas is different from that in normal landforms. Aiming at the phenomenon of large-scale farmland abandonment in the karst region of Southwest China, this study investigated the characteristics of farmland abandonment in different rocky desertification control areas of typical counties. We interpreted land use changes in the study area using high-resolution images (5 m) in 2010 and 2020 through human–computer interaction. After removing patches of converted farmland to forests, we extracted the spatial distribution of abandoned farmland. The study area was found to have a high abandonment rate (24.83 %), with dryland showing 2–3 times higher abandonment rate than paddy fields. The abandoned area in rocky desertification dryland accounts for 50.57 % (499.04 km2) of the abandoned area of karst dryland. It is worth noting that the abandonment rate of non-rocky desertification dryland in the karst dryland is the lowest (22.45 %), while the abandonment rate of dryland shows no significant difference among other rocky desertification grades, with an average of 28.00 %. In addition, with the change of rocky desertification level, the index of abandonment degree showed a trend of initial increase followed by a decrease. Slope, lithology and soil type have a joint effect on karst dryland abandonment. Slope is the core factor affecting karst dryland abandonment, and the interaction between slope and soil type is the dominant factor affecting its change. The results of this study show that farmland abandonment is serious in karst rocky desertification areas, primarily occurring in rocky desertification dryland. The government should take targeted management measures based on the current status of abandoned drylands at different levels of rocky desertification, especially in sloping farmland areas.

Responses of soil microbial biomass, microbial entropy and soil-microorganism stoichiometry imbalance to different utilization patterns in the artificial grassland of karst desertification area

Different utilization patterns can alter the C, N, P cycles and their ecological stoichiometry characteristics in grassland soils. However, the effects of different utilization patterns on soil microbial biomass, microbial entropy and soil-microorganism stoichiometry imbalance of artificial grassland are not clear. So this study was took different utilization patterns of artificial grassland [i.e., grazing grassland (GG), mowing grassland (MG), enclosed grassland (EG)] as the research object to investigate responses of soil microbial biomass, microbial entropy and soil-microorganism stoichiometry imbalance to different utilization patterns in the karst rocky desertification control area. We found that the contents of microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) were highest in GG, and the content of microbial biomass phosphorus (MBP) was highest in EG. Soil microbial biomass entropy carbon (qMBC) and soil microbial biomass entropy nitrogen (qMBN) of GG and MG were higher than those of EG, but soil microbial biomass entropy phosphorus (qMBP) was opposite. C:N stoichiometry imbalance (C:Nimb) was EG > GG > MG, C:P stoichiometry imbalance (C:Pimb) was EG > MG > GG, N:P stoichiometry imbalance (N:Pimb) was MG > EG > GG. MBN was significantly positive correlated with C:Nimb and C:Pimb, MBC was significantly negative correlated with C:Pimb, MBP was significantly negative correlated with N:Pimb. The redundancy analysis (RDA) results showed that N:Pimb (p = 0.014), C:Nimb (p = 0.014), and C:P in the soil (C:Psoil, p = 0.028) had the most significant effect on microbial entropy. EG had a significant effect on soil microbial biomass and microbial entropy. The results of this study can directly or indirectly reflect the grassland soil quality under different utilization patterns in the karst rocky desertification area, which has a certain reference value for the degraded ecosystem restoration.

Study on the Ecosystem Service Supply–Demand Relationship and Development Strategies in Mountains in Southwest China Based on Different Spatial Scales

Mountainous regions typically exhibit a strained relationship between humans and the land, with noticeable spatial differences in the supply and demand of ecosystem services (ESS and ESD, respectively). ESS and ESD display varying characteristics at different spatial scales. Research on ESS and ESD at multiple scales can aid regional development and efficient ecosystem management. However, the current research focuses on ESS and neglects the ES characteristic changes at different scales. This study concentrates on the Hengduan Mountain region in southwest China. It evaluated ESS and ESD, analyzed the spatial matching relationship, and proposed a corresponding development strategy. The results demonstrated four key findings. First, ESS displayed an inverse spatial distribution on the two scales and was lower in the north and higher in the south at the raster scale. Over the period 2000–2020, ESS exhibited a pattern of initial increase, followed by a decrease, albeit with varying spatial patterns. Changes in land use primarily drove these ESS changes. Second, ESD increased from northwest to southeast on both scales and showed a rising trend over time. Third, at the grid scale, the low supply and low demand (L-L) region is primarily situated in the northwestern part, and it is crucial to prevent grassland degradation and manage grazing intensity. The low supply and high demand (L-H) region is located in the southeast, where the protection of cultivated land, along with comprehensive control of rocky desertification and debris flow, should be prioritized. High supply and low demand (H-L) are found in the northern mountain area, where paying attention to soil erosion control is essential. For areas with high supply and high demand (H-H) types, efforts should be directed toward maintaining forest habitat integrity. Fourth, on the county scale, L-H types should focus on realizing the ecosystem service value and implementing ecological agriculture. H-L counties can appropriately develop economic activities. Simultaneously, ecological compensation should be conducted among counties.

Response of leaf blade in Zanthoxylum planispinum var. dintanensis to differences altitudes through integrated metabolomics and transcriptomics analysis

To analyze the effects of altitude on Z. planispinum var. Dintanensisin, leaves of samples from different altitudes (H1:1054 m.a.s.l., H2:821 m.a.s.l., H3:645 m.a.s.l.) were collected for integrative analysis of the metabolome and transcriptome in the present study. According to transcriptome data, a total of 9,566 differentially expressed genes (DEGs) were identified from the three sample comparisons (H1 vs. H2, H1 vs. H3, H2 vs. H3). Fewer DEGs were observed in the H2 vs. H3 group than in the other two comparison groups, suggesting that differences in the transcriptome increased with elevation. Most genes were involved in “Biosynthesis of secondary metabolites”, “Plant hormone signal transduction” and “MAPK signaling pathway-plant” based on KEGG enrichment analysis. In total, 423 differential metabolites (DAMs) were determined in the three comparisons (mentioned above) by using metabolomics analysis, of which flavonoids (14.91%) were dominant. Interestingly, more accumulation of terpenoids, aldehydes and esters was observed at higher altitudinal levels, while higher percentages of flavonoids and polyphenols were obtained at lower altitudes based upon K-Means analysis. A unique pathway (p value<0.01) linked to “flavonoid biosynthesis” appeared to have consistent expression patterns in the comparison of H1 vs. H3 based on network analyses of DEGs and DAMs. Notably, regarding the direct products of catalytic reactions, naringenin chalcone, aromadendrin, and naringenin were positively regulated by genes encoding CHS, F3H and CHI, respectively. In addition, the transcription levels of nine candidate genes, including CHI, CHS, CCoAOMT, 2ODDs, ANS, ANR, F3H, DFR and HCT, were confirmed by RT‒qPCR, which were consistent with transcriptional profile data regarding RNA-seq and further demonstrated that these genes involved in flavonoid biosynthesis contribute to the environmental adaptation of the blade in Z. planispinum var. Dintanensis. In summary, our findings represent the first integration of transcriptome data with widely targeted metabolomic data from Z. planispinum var. Dintanensis grown in rocky desertification control areas, which provides novel insights into adaptation to environmental stress. This study has the potential to improve the cultivation and management of Z. planispinum var. Dintanensis through various technologies to gain maximum medicinal production in the future.

Vegetation restoration in South China’s karst region under geological background constraint: Forest or non-forest

Over the past two decades, the karst region in southern China has emerged as a critical area for ecological conservation and restoration, attracting global attention for its efforts in ‘greening.’ However, particular areas face challenges transitioning into forests due to the carbonate bedrock constraint, which likely undermines sustainability of greening efforts in karst regions. This study overviews the significant achievements in vegetation restoration in the karst region of southwest China, emphasizing the potential of short-term ecological restoration in effectively sequestering carbon, a valuable approach to achieving carbon neutrality in the region. However, combating rocky desertification remains difficult due to geological limitations that hinder large-scale afforestation. Additionally, variations in soil and rock composition impact the success and quality of vegetation restoration, leading to some areas failing to establish forests. Therefore, establishing the goals for rocky desertification control in different regions (enhancement, degradation, or reduction) should be based on current conditions and the evolutionary characteristics of rocky desertification. To facilitate precise afforestation and grass planting in the karst region, factors such as climate, rock conditions, and human-environment relationships should be considered in regional divisions, including natural restoration zones, artificial afforestation zones, grass planting zones, and protected zones.

Spatial pattern of hydrological and erosion behaviour along a dolomite hillslope in Southwest China

Dolomite hillslopes are highly vulnerable to rocky desertification, but the linkages among soil type, runoff mechanisms, and soil erosion remain unclear. During four hydrological years (2018–2021), soil type, plot-scale hydrological and erosion behavior at the upper, middle, and lower slopes along the dolomite hillslope in karst regions of Southwest China were investigated. The results indicated that along the downward slope direction, the degree of soil development gradually increased, forming a typical soil catena pattern. The soil types along the downward direction on the dolomite hillslope gradually transitioned from Entisol to Inceptisol and to Semi-Alfisol. The Entisol was thin and gravelly, with the highest volume ratio of gravel of 75 %. In contrast, Semi-Alfisol was thick and clayey, with the highest volume ratio of fine soil of 97 %. The surface runoff coefficient of the upper slope was only 2.3 % because of the high water infiltration capacity of shallow and rocky soil, and the runoff generation mode was dominated by discontinuous infiltration–excess runoff occurring on rock outcrop patches. Due to the higher soil water content (mean value of 37 %) and frequently occurring lateral flow, the lower slope exhibited the highest surface runoff coefficient of 21 %, mainly as saturation-excess runoff. Catenary soils and their correspondingly divergent hydrological regimes led to average annual soil losses of 0.4, 0.8, and 2.8 t·ha−1·yr−1 at the upper, middle, and lower slopes, respectively. These results advance the understanding of the relationship between hydrology and erosion on karst hillslopes and provide theoretical support for further rocky desertification control.

Rhizospheric soil organic carbon accumulated but its molecular groups redistributed via rhizospheric soil microorganisms along multi-root Cerasus humilis plantation chronosequence at the karst rocky desertification control area.

Though the relationships between the microorganism communities and the edaphic factors in rhizosphere soil along the plantation chronosequence have been widely reported, few researches have appeared on the interrelationship about rhizospheric soil microorganism community and soil organic carbon (SOC) under multi-root Cerasus humilis plantations of different age. In our study, the rhizospheric soil microbial communities, soil physicochemistry, and SOC molecular groups in plantations of 1-, 3-, and 5-year-old Cerasus humilis were investigated in karst rocky desertification control area of southwest China. It was found that karst rhizospheric soil moisture, total nitrogen, available potassium, and 46-60ppm N-alkyl/methoxyl C decreased; however, SOC and fungal:bacterial ratio decreased along multi-root Cerasus humilis plantation chronosequence. Proteobacteria, Actinobacteriota, Acidobacteriota, and Ascomycota were recognized as the top 4 phyla in the karst rhizospheric soil microbial co-occurrence network. Moreover, Cerasus humilis plantations exerted significantly direct effect on rhizospheric soil microbial communities and soil physicochemical properties exerted significantly direct effects on SOC molecular groups. Our results suggested that the increased Cerasus humilis plantation years will promote C sequestration (e.g., SOC) with the continued input of root litter, root exudates, and plant litter. The inputted and activated C can be preferentially consumed by rhizospheric soil microorganisms and converted into microbial-derived compounds, which are finally incorporated into recalcitrant SOC pools. Hence, Cerasus humilis redistributed SOC molecular groups via rhizospheric soil microorganisms, and increased ratio of fungi:bacteria in rhizosphere was associated with C sequestration which could not be regarded as a widespread rule. Though our study is the first attempt to recognize the interaction between rhizospheric soil microbial community and SOC molecular groups at the karst rocky desertification control area, it provides a baseline for further research that ecological restoration can promote soil C sequestration via soil microorganisms in the early period of eco-restoration at karst area.

Ecological restoration projects enhanced terrestrial carbon sequestration in the karst region of Southwest China

The karst region of southwest China showed a significant increase in vegetation cover and vegetation carbon stocks under the implementation of a series of ecological restoration projects. However, the relative contribution of ecological restoration projects to terrestrial carbon sequestration in the context of climate change has yet to be well quantified. Here, we used the Community Land Model (CLM4.5) to investigate the trend of net ecosystem productivity (NEP) and attribution to multiple environmental factors in the karst region of southwest China during 2000–2018. The result showed that ecosystems with a significant increasing trend of NEP covered about 46% of the study region, which were mainly located in the peak forest plain region, colliculus region, peak cluster depression region, and middle-high hill region. The simulation experiments suggested that land use change associated with ecological restoration projects caused a large contribution of 53% to the increasing NEP trend, followed by CO2 fertilization (72%), while climate factors and nitrogen deposition showed minor negative effects. Especially, the NEP trend induced by land use change in the 100 pilot counties with the implementation of rocky desertification control project was significantly higher than that in the other karst area. Moreover, moderate and high levels of restoration efforts invested into recovery led to a larger increasing trend (0.66 gC/m2/yr2 and 0.48 gC/m2/yr2) in NEP than the low efforts level (0.22 gC/m2/yr2). Our results highlight the important role of ecological restoration projects in the enhanced terrestrial carbon sequestration in the karst region of southwest China, and recommend a comprehensive assessment of ecological restoration projects for policymaking.

Research on the Resilience Assessment of Rural Landscapes in the Context of Karst Rocky Desertification Control: A Case Study of Fanhua Village in Guizhou Province

The ecological rehabilitation project has greatly curbed the serious problem of karst rocky desertification (KRD) in southern China and significantly changed the ecological environment and landscape pattern of the karst rocky desertification control areas (KRDCA). As one of the most important social–ecological fragile areas in the world, rural landscapes in KRDCA still show a strong sensitivity to disturbance. To reduce risks and improve the resilience of landscapes, this paper constructs a framework for assessing rural landscape resilience in KRDCA from the three dimensions of ecology, engineering, and social culture, based on the concept of resilience defined by the United Nations International Agency for Disaster Reduction. Considering the characteristics of rural landscapes in KRDCA, we select typical villages for empirical study. The results show the following: (1) The KRDCA is highly sensitive to natural disasters due to its special dual geomorphic structure characteristics. The disaster preparedness capacity of villages is the key factor determining the resilience of rural landscapes. The analysis of the disaster preparedness capacities of rural landscape structures with different vulnerability characteristics can be used as an effective means of evaluating the resilience level of rural landscapes in KRDCA. (2) Based on the empirical analysis of Fanhua village, which is a typical KRDCA in southern China, we found that the ecological system and engineering system of the village landscape have high resilience, while the resilience of the social and cultural systems are weak. This is due to the fact that the large number of rural population emigration in recent years has resulted in villages being at the key node of the reorganization of the social and cultural value system. The unstable sociocultural value system reduces the ability of rural landscapes to adapt to disturbance or environmental change. The study results could guide improvement strategies for subsequent landscape planning and inspire new ideas and methods for the implementation of rural revitalization strategies and the improvement of landscape resilience in KRDCA.

Changes in Plant Diversity and Soil Factors under Different Rocky Desertification Degrees in Northern Guangdong, China

Revegetation is an important restoration strategy for the control of rocky desertification. However, few studies have focused on the effects of different rocky desertification degrees (RDDs) on plant diversity and soil fertility in northern Guangdong over long periods of time. In this study, variance analysis, correlation analysis, and canonical correlation analysis (CCA) were used to examine plant diversity, soil physicochemical properties, and their correlations in various rocky desertification areas in northern Guangdong. The results showed that the Pinaceae, Lauraceae, and Fagaceae species were relatively abundant in the rocky desertification areas of northern Guangdong. Additionally, Cinnamomum camphora, Schima superba, Pinus massoniana, Quercus stewardiana, and Acer camphora could be used as indicators for rocky desertification. There were significant differences in plant community compositions and diversity characteristics between the five RDDs, and the vegetation exhibited the trend of initial destruction and then gradual improvement and stabilization. There were significant differences in soil bulk density, mechanical composition, organic matter, total nitrogen, alkaline hydrolysis nitrogen, and available potassium between the different RDDs. Except for pH, the soil chemical characteristics all had clear aggregation effects. Soil organic matter, total nitrogen, total potassium, and alkaline hydrolysis nitrogen all exhibited degradation–improvement cycles. The correlation analysis revealed that there was a significant correlation between soil physicochemical properties and species diversity. The CCA analysis showed that the most important soil factors affecting plant community structures were total phosphorus and available phosphorus. In conclusion, some achievements have been made in the restoration of rocky desertification in northern Guangdong; while the plant community structure improved, some soil nutrients also improved. Vegetation and soil have a strong coupling relationship. In the later stages of recovery, suitable species for rocky desertification could be considered in varying degrees and P and K could be supplemented appropriately. Our study will have implications for the revegetation of rocky desertification.

Effects of vegetation restoration on distribution characteristics of heavy metals in soil in Karst plateau area of Guizhou.

In southwest China, vegetation restoration is widely used in karst rocky desertification control projects. This technology can effectively fix the easily lost soil, gradually restore the plant community and improve soil fertility. However, the change law of soil heavy metals in the restoration process remains to be further studied. Therefore, in this work, Guizhou Caohai Nature Reserve as a typical karst area was taken as the research object to investigate the influence of vegetation restoration technology on repairing soil heavy metal pollution. The spatial distribution characteristics of soil heavy metals (chromium, nickel, arsenic, zinc, lead) before and after vegetation restoration in karst area were studied by comparative analysis and linear stepwise regression analysis. The main influencing factors and spatial distribution characteristics of heavy metals in karst area were further discussed. The results showed that: (1) heavy metals in karst soils are affected by surface vegetation, root exudates, microorganisms and leaching. Only heavy metals nickel (Ni) and lead (Pb) showed the tendency of surface enrichment and bottom precipitation enrichment in non-karst soils. Path analysis suggested that non-metallic soil factors such as soil bulk density (BD), total nitrogen (TN) and ammonium nitrogen (NH4 +-N) had direct effect on the content of heavy metals in soil. (2) The proportion of 0.25-2 mm aggregates in the surface soil of vegetation restoration belt was more than 40%, and the proportion of surface soil ≤2 mm aggregates in this increased to 83% and 88%, respectively, which could improve the soil structure and properties effectively. (3) Vegetation restoration effectively restored the nutrient elements such as carbon and nitrogen in the soil, and enhanced the soil material circulation. Furthermore the content of heavy metals in the surface soil higher than that in the 10-20 cm soil layer. Plant absorption, biosorption mechanism of microorganisms, coupling of root exudates, dissolution of soil soluble organic carbon and pH make the contents of heavy metals Cr, Ni and Pb in vegetation restoration belt slightly lower than those in karst soil. At the same time, affected by vegetation coverage, residual heavy metals in soil are further leached by surface runoff. Therefore, the content of heavy metals in soil could reduce combined heavy metal enrichment plants for extraction with remediation. This study elucidates the advantages and remedy mechanism of vegetation restoration in the remediation of heavy metal contaminated soils in Caohai area of Guizhou, and this plant activation and enrichment extraction remediation technology would be popularized and applied in the remediation of heavy metal contaminated soils in other karst areas.

Diversity and Community Structure of Typhlocybinae in the Typical Karst Rocky Ecosystem, Southwest China

In karst ecosystems, different geographic environmental conditions can lead to different lithospheric conditions, thus determining community composition and altering biotic interactions. Guizhou Province is a typical ecologically fragile karst area located in the South China Karst. To explore the relationship between biodiversity and environmental changes in different karst habitats, the community structure of typhlocybinae (Hemiptera, Auchenorrhyncha, and Cicadellidae) in three typical karst areas in Guizhou Province (the Zhenfeng–Huajiang Demonstration Zone, the Bijie Salaxi Demonstration Zone, and the Shibing Yuntai Mountain Nature Reserve) was analyzed. These areas are characterized by differences in terms of their geographic environment. For field investigations, typhlocybinae specimens were collected from five common leafhopper host plants—Juglans regia L., Rhus chinensis Mill., Prunus persica (L.) Batsch, Prunus salicina Lindl., and Debregeasia orientalis C.J. Chen—in the three study areas. A total of 4078 typhlocybinae specimens were captured, belonging to 6 tribes, 40 genera, and 121 species. Among them, Alnetoidia dujuanensis, Limassolla lingchuanensis, and Singapora shinshana were the dominant species. The numbers of typhlocybinae specimens from each region were as follows: Shibing, 2170 (53.2%); Bijie, 973 (23.9%); and Huajiang, 935 (22.9%). The number of leafhoppers collected in areas with serious rocky desertification was low, and the number increased with the increase in vegetation coverage. The order of the influence of environmental factors on the community structure of the leafhoppers in the three study areas was Huajiang &gt; Bijie &gt; Shibing. This order is consistent with the ranking of rocky desertification grades in the three study areas. The order based on the number of units at different taxonomic levels was as follows: Bijie (6 tribes, 32 genera, and 68 species) &gt; Huajiang (6 tribes, 22 genera, and 58 species) &gt; Shibing (5 tribes, 21 genera, and 48 species). The results show that environmental factors, such as climate and host plant leaf traits, had various effects on the characteristics and diversity of the leafhopper communities in different grades of rocky desertification areas. This study demonstrates that there are differences in species diversity in different grades of karst rocky desertification areas and provides a theoretical basis for future rocky desertification control and regional ecological restoration.

Research Progress of Grassland Ecosystem Structure and Stability and Inspiration for Improving Its Service Capacity in the Karst Desertification Control

The structure and stability of grassland ecosystems have a significant impact on biodiversity, material cycling and productivity for ecosystem services. However, the issue of the structure and stability of grassland ecosystems has not been systematically reviewed. Based on the Web of Science (WOS) and China National Knowledge Infrastructure (CNKI) databases, we used the systematic-review method and screened 133 papers to describe and analyze the frontiers of research into the structure and stability of grassland ecosystems. The research results showed that: (1) The number of articles about the structure and stability of grassland ecosystems is gradually increasing, and the research themes are becoming increasingly diverse. (2) There is a high degree of consistency between the study area and the spatial distribution of grassland. (3) Based on the changes in ecosystem patterns and their interrelationships with ecosystem processes, we reviewed the research progress and landmark results on the structure, stability, structure-stability relationship and their influencing factors of grassland ecosystems; among them, the study of structure is the main research focus (51.12%), followed by the study of the influencing factors of structure and stability (37.57%). (4) Key scientific questions on structural optimization, stability enhancement and harmonizing the relationship between structure and stability are explored. (5) Based on the background of karst desertification control (KDC) and its geographical characteristics, three insights are proposed to optimize the spatial allocation, enhance the stability of grassland for rocky desertification control and coordinate the regulation mechanism of grassland structure and stability. This study provided some references for grassland managers and relevant policy makers to optimize the structure and enhance the stability of grassland ecosystems. It also provided important insights to enhance the service capacity of grassland ecosystems in KDC.