Rocky Desertification Control Research Articles

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.

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.

Temporal Variations of Sediment Provenance in a Karst Watershed, China

The environmental quality of the sediments in karst areas is a common concern, and it is of great significance to analyze the sources of the sediments. This study investigates the sources and its temporal variations of catchment sediments in a typical small karst watershed area. Toxic metal concentrations in the catchment area were monitored via three geochemical baseline projects in China. The sediment identification fingerprint tool (SIFT) was used to establish a geochemical model for tracing the main source contributions and its temporal variations of catchment sediments over the past 28 years (1992–2019). The catchment sediments in the small karst catchment area were mainly sourced from the background lithologies, among which limestone contributed the most, followed by dolomite, sand-shale, and mudstone; however, the anthropogenic lead–zinc tailings contributed the least. The contributions and temporal variations of each source were closely related to the lithology, topography, and landform, as well as the change in land-use and vegetation cover and the degree of rocky desertification. Moreover, the implementation of vegetation restoration and control of rocky desertification decreased the contributions of the upstream geological bodies, and the toxic metal content of the catchment sediment decreased accordingly. This study is of great significance for environmental governance in karst areas.

西南喀斯特地区耕地撂荒生态环境效应研究进展

PDF HTML阅读 XML下载 导出引用 引用提醒 西南喀斯特地区耕地撂荒生态环境效应研究进展 DOI: 10.5846/stxb202104050878 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（42167044，42007054）；中国博士后科学基金项目（2020M673296）；贵州省研究生科研基金项目（黔教合YJSCXJH[2020]066） Research progress on the ecological environment effect of farmland abandonment in karst areas of Southwest China Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:耕地撂荒是多驱动力综合作用的结果，不同地域下的撂荒地生态环境影响具有其特殊性。针对当前西南喀斯特地区耕地撂荒现象，综述了目前在西南喀斯特地区撂荒地生态环境影响方面取得的研究进展及未来的研究展望。综合现有研究结果发现：①务农机会成本增加，以粗放经营为主要特点的隐性撂荒可能是现代石漠化发展的潜在动力；②喀斯特地区的土壤异质性决定了耕地撂荒后地块尺度的景观均质性或者区域尺度的景观异质性；③喀斯特地区耕地撂荒后植被恢复能在一定程度上改善土壤结构、维持土壤水分、促进土壤养分恢复；④撂荒初期土壤侵蚀加剧，撂荒后期植被恢复防治土壤侵蚀；⑤耕地撂荒植被恢复后增强了喀斯特地区植被碳汇、土壤碳汇和岩溶碳汇效应。未来，应明确隐性撂荒对喀斯特地区生态环境的具体影响，创新技术手段动态监测优等地和石漠化耕地的撂荒面积及趋势变化，定量显性撂荒在水土流失防治和石漠化生态恢复中的贡献，综合评估撂荒地的碳汇效应，从而为合理配置喀斯特地区耕地的社会、生态功能建言献策。 Abstract:Farmland abandonment is the result of comprehensive effects by multiple driving forces. Ecological environment impact by farmland abandonment has its particularity in different regions. Aiming at the current phenomenon of farmland abandonment in the southwest karst areas, this paper summarizes the current research progress and future research prospects on the ecological environment impact of farmland abandonment in karst areas of the southwest China. By summarizing existing studies on ecological and environmental effects by farmland abandonment, it revealed that:(1) the opportunity cost of farming increased. The implicit abandonment being mainly characterized by extensive management may be the potential driving force for modern development of rocky desertification; (2) The soil heterogeneity in the karst areas determines the landscape homogeneity at the plot scale or the landscape heterogeneity at the regional scale after a farmland abandoned; (3) Vegetation restoration after abandonment of farmland in karst areas can improve soil structure, maintain soil moisture and promote soil nutrient restoration to a certain extent; (4) Soil erosion intensifies in early stage of abandonment, and soil erosion will be prevented and controlled by restoration of vegetation in later stage of abandonment; (5) The restoration of vegetation on abandoned farmland enhances the effects of plant carbon sink, soil carbon sink and karst carbon sink in karst areas. In the future, the specific impact of implicit abandonment on ecological environment of karst areas should be clarified, innovative technical means should be used to dynamically monitor the abandoned area of prime farmland and rocky desertified farmland, as well as their abandonment trend changes, the contribution of explicit abandonment in soil erosion control and ecological restoration of rocky desertification should be quantified, and the carbon sink impact of abandoned land should be comprehensively assessed. Therefore, it may offer suggestions for the rational allocation of social and ecological functions of farmland in karst areas. 参考文献 相似文献 引证文献

岩溶区不同土地利用方式下土壤CO2排放模拟研究

PDF HTML阅读 XML下载 导出引用 引用提醒 岩溶区不同土地利用方式下土壤CO2排放模拟研究 DOI: 10.5846/stxb202111223290 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（42072278，42177248）；贵州省科技计划项目（黔科合支撑[2020]4Y013号） Simulation experiment on soil CO2 emission by different land uses in karst area Author: Affiliation: Fund Project: The national natural science foundation of China(42072278,42177248); Guizhou Science and Technology Supporting Plan (No. 2020-4Y013) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:土地利用变化作为全球气候变化研究的重要内容之一，对土壤CO2的排放具有重要影响。岩溶区石漠化治理过程中植被恢复伴随着土地利用方式的转变，其对土壤CO2排放的影响有待进一步研究。基于控制性实验，以土壤、岩溶含水介质初始条件相同，仅土地利用方式不同的贵州普定沙湾模拟试验场为研究对象，通过1年的土壤CO2浓度和通量数据，研究岩溶区不同土地利用方式下土壤CO2的排放规律及其影响因素。结果表明：（1）土壤CO2的浓度和通量具有明显的季节变化规律，不同季节下的土壤CO2通量呈现昼夜变化规律，温度和降雨影响着土壤CO2的排放，前者可促进排放量，后者可抑制排放量，且不同土地利用方式受影响的程度不同；（2）耕作活动也会影响土壤CO2的排放，耕作使得土壤变得松散，加上岩溶区下伏基岩的溶蚀作用，增加了土壤CO2向含水层的扩散，导致春季耕地表现为负通量；（3）不同土地利用方式下土壤CO2的年排放量不同，具体为草地（897.53 tC km-2 a-1）>灌木地（258.15 tC km-2 a-1）>耕地（207.66 tC km-2 a-1）>裸土地（92.68 tC km-2 a-1），究其原因，主要受不同土地利用下植被生物量和土壤有机碳含量的影响；（4）不同土地利用下的土壤有机碳含量为草地（29.33 g/kg）>灌木地（23.31 g/kg）>耕地（22.08 g/kg）>裸土地（19.00 g/kg），鉴于这些土壤的初始性质相同，研究发现随着土地利用方式的改变，除无植被的裸土地土壤有机碳含量减小外，其余有植被的类型均有增加，且增加的程度和植被覆盖的程度有关。综上，不同土地利用类型可以通过影响上覆植被的生物量和土壤有机碳含量，进而控制土壤CO2的排放，而排放强弱与温度、降雨和耕作活动有关，可以通过土地利用方式的调整来增加土壤有机质含量和土壤储碳。 Abstract:As one of the important parts of global climate change research, land use change plays a significant role in soil CO2 emission. In karst area, vegetation has been restored in the process of rocky desertification control, accompanied by the change of land use, and its impact on soil CO2 emission needs to be further clarified. Based on the controlled experiment, with the same initial conditions of soil and karst aqueous media but different land uses, the Shawan Test Site at Puding, Guizhou was chosen to study the emission law and influencing factors of soil CO2. Through the soil CO2 concentration and flux data in a hydrological year, our results demonstrated that:(1) the soil CO2 concentration and flux showed obviously seasonal variations, and the soil CO2 flux had apparent diurnal variation in different seasons. They were mainly controlled by temperature and rainfall. The former could increase the emission, while the latter could decrease the emission, and the increased or decreased degrees were related to land uses. (2) Farming activities affected the soil CO2 emission as well. Due to the dissolution of the underlying carbonate rock in karst area, farming activities could make the soil loose and increase the diffusion of soil CO2 to the aquifer, resulting in negative soil CO2 flux of cultivated land in spring. (3) The annual emission of soil CO2 under different land uses were grassland (897.53 tC km-2 a-1) > shrub land (258.15 tC km-2 a-1) > cultivated land (207.66 tC km-2 a-1) > bare soil land (92.68 tC km-2 a-1). It was found that they were mainly dominated by vegetation biomass and soil organic carbon content under different land uses. (4) The contents of soil organic carbon were grassland (29.33 g/kg) > shrub land (23.31 g/kg) > cultivated land (22.08 g/kg) > bare soil land (19.00 g/kg). Given the same initial properties of these soils, we found that with the change of land use, except for the soil organic carbon content in non-vegetated bare soil land decreased, the other types increased, and the increased degree was related to the degree of vegetation coverage. Therefore, land use types could control soil CO2 emission by affecting the biomass of overlying vegetation and the soil organic carbon content, and the emission intensity is related to temperature, rainfall process and farming activities. Further, we think that the content of soil organic matter and soil carbon storage could be increased through the adjustment of land use. 参考文献 相似文献 引证文献

Development of Circulation Mechanism and Mode of Ecological Products and Its Enlightenment to Ecological Industry of Rocky Desertification Control

Development of Circulation Mechanism and Mode of Ecological Products and Its Enlightenment to Ecological Industry of Rocky Desertification Control

Revelation of Coupled Ecosystem Quality and Landscape Patterns for Agroforestry Ecosystem Services Sustainability Improvement in the Karst Desertification Control

Since the 1950s, the rapid depletion of natural capital due to human activities has led to a growing global demand for ecological and socioeconomic sustainability, driving the development of agroforestry. Although agroforestry ecosystems can maintain sustainable land resources and maximize land productivity, their quality continues to fluctuate. Moreover, there is no clear review of studies addressing the impact of the evolution of agroforestry landscape patterns on their ecosystems, and to fill this gap, we conducted an inclusive review. A total of 163 publications related to agroforestry ecosystem quality and landscape patterns (ELA) that met a set of inclusion criteria were obtained through the Scopus database using the literature review method of searching, appraisal, and synthesis report. The objectives were to summarize the research progress on ELA, reveal the dynamic coupling mechanism between landscape pattern evolution and ecosystem quality, explore the role of landscape pattern optimization in ecological processes and services in agroforestry, and suggest future research and policy directions. Although the understanding of landscape patterns and ecological processes has been deepened, there are limitations in the study of scales, habitats, and other aspects. It is emphasized that understanding the interaction between agroforestry and other landscape elements in spatiotemporal organization is a prerequisite for promoting sustainable benefits, and that the challenges of spatiotemporal dynamics are integrated to scientifically optimize agroforestry landscape patterns. Finally, it is necessary to gain revelations based on the coupling relationship of ELA, through scientific management of agroforestry landscapes, in order to sustainably consolidate the effectiveness of karst rocky desertification (KRD) control and to enhance human welfare.

Ecological Quality Evolution and Its Driving Factors in Yunnan Karst Rocky Desertification Areas

Rocky desertification is a key element affecting regional ecological quality. Rocky desertification in Southwest China directly affects the ecological security of the Yangtze River and Pearl River basins and also restricts regional economic and social development. In order to clarify the evolution laws and key influencing factors of ecological quality in Yunnan karst rocky desertification areas, a quantitative analysis based on the remote sensing-based ecological index (RSEI) model was conducted to explore the overall evolution characteristics and change laws of ecological quality in Yunnan karst rocky desertification areas in the past 30 years. The correlation between RSEI, rock outcrop rate (Fr), and driving factors was determined by redundancy analysis. The results showed the following: (1) RSEI in Yunnan karst rocky desertification areas generally showed a decreasing trend, with a fluctuation in the mid-term, followed by a tendency to recover. It fell into three stages: decline, trough, and recovery, with fitting coefficients of -0.121, -0.057, and 0.157, respectively. In contrast, Fr showed an opposite tendency, illustrating the inverse relationship between RSEI and Fr, and the rate of sequential succession was much faster than that of the reverse succession under human measures of intervention. (2) The mean value of RSEI of Yunnan karst rocky desertification areas was generally lower than that of the total Yunnan Province land areas and Yunnan non-karst rocky desertification areas, but the mean value of Fr was generally more than that of both the above-mentioned areas. In addition, the RSEI and Fr of Yunnan karst rocky desertification areas both showed lower stability values than those of both the above-mentioned areas. This generally suggested a low ecological quality and a high degree of desertification under a low stability in Yunnan karst rocky desertification areas. (3) The correlation of RSEI and Fr with driving factors followed the order of topographic factors, soil factors > water factors > anthropogenic factors. Anthropogenic factors were the driving force changing the state of rocky desertification, geological factors such as topography and soil to a larger extent determined the original macroscopic ecological relationship of rocky desertification, and water factors lay between the above two. The findings of this research will provide theoretical support and a basis for the improvement of ecological quality and comprehensive control of karst rocky desertification in Yunnan Province.