China Karst Research Articles

PhytOC sequestration characteristics and phytolith carbon sink capacity of the karst grasslands in southwest China

Grassland is an important component of terrestrial ecosystems and plays a crucial role in the global carbon cycle. PhytOC (phytolith-occluded organic carbon) is an extremely important long-term and stable carbon pool in terrestrial ecosystems. Southwest China karst soil exhibits obvious characteristics of alkalinity, high silicon content, and rich calcium, which can significantly influence the characteristics and mechanisms of PhytOC sequestration in vegetation. To elucidate the sequestration characteristics and mechanisms of PhytOC in the karst grasslands, three typical karst grasslands of tropical shrub tussock (TST), warm-temperate shrub tussock (WST), and mountain meadow (MM) from Guizhou province of southwest China were studied. The following results and conclusions were obtained that: 1) the range of PhytOC content of aboveground plant parts, underground roots, and soil in the karst grasslands was 4.03–16.54 g·kg−1, 10.67–33.92 g·kg−1, and 0.63–1.89 g·kg−1, respectively. The underground roots are an important site for phytolith carbon sequestration in grassland ecosystems, and the PhytOC content of underground roots may be higher than that of the aboveground parts. 2) The PhytOC sequestration rate of vegetation was 7.34–15.93 kg·ha−1·yr−1, and the annual sequestration amount of PhytOC of the whole grasslands in southwest China could reach 0.48 × 103–1.48 × 103 t CO2. Compared to grasslands in non-karst regions of China, karst grasslands in southwest China have a higher sequestration rate of PhytOC in vegetation and a greater capacity for phytolith carbon sequestration. 3) Soil available silicon, pH, and stoichiometric characteristics of C, N and P nutrients significantly affected the phytolith carbon sequestration of vegetation and the soil accumulation of PhytOC in the karst grasslands. The research results are of great significance for estimating the phytolith carbon sequestration capacity of grassland ecosystems and for grassland construction and management based on enhancing carbon sequestration.

Social-ecological heterogeneity drove contrasting tree cover restoration in South China Karst

South China Karst is the world’s largest continuous karst zone and is becoming the hotspot of greening earth. However, the greening sustainability remains uncertain due to challenges from carbonate geological constraints and oversights in recognizing synergies within social-ecological systems. Here, the sustainability and drivers of tree cover restoration were quantitatively investigated in South China Karst. The area with tree cover increasing was 652,457 km2, about 33.67% of the study area. There were differences in ecological elements between karst and non-karst areas, and rural population decrease in undeveloped areas could greatly promote tree cover restoration. Moreover, the correlation degree of social-ecological network in karst area was obviously lower than that in non-karst area, indicating higher heterogeneity of social-ecological system in karst area. This study highlights the social-ecological effects on tree cover restoration in karst area, and a shift in focus from the natural ecosystem to coupled social-ecological systems is crucial for sustainable forest management.

Quantifying the biodiversity and ecosystem service outcomes of karst ecological restoration: A meta-analysis of South China Karst

Decades of restoration efforts have greened South China Karst, the largest and most concentrated karst area in the world. However, it is unknown whether and how the observed increase in vegetation coverage could enhance biodiversity and the provision of ecosystem services (ES). In this study, we performed a meta-analysis of 108 studies with 6505 observations to quantify the influence of karst ecological restoration on biodiversity and ES provision and to uncover key factors that may influence restoration outcomes. We found that restored karst lands on average provided 29 % and 18 % higher biodiversity and ES than degraded karst lands, respectively, but 14 % and 29 % lower than intact reference karst lands. However, the outcomes of karst ecological restoration were mediated by restoration strategy, vegetation type, and restoration age. Natural restoration actions often had more positive effects on biodiversity and ES than reconstructive restoration actions. Karst restoration outcomes also increased with the progress of vegetation succession and increasing restoration age. Furthermore, ES outcomes were positively correlated with biodiversity outcomes, demonstrating the importance of incorporating the biodiversity-ecosystem functioning relationship into karst restoration actions. Overall, our study suggests that karst ecological restoration has substantial potential to improve biodiversity and the provision of ES, but restoration outcomes are context-dependent. These findings may inform evidence-based decision making for biodiversity conservation and sustainable development in karst regions, especially with the UN Decade on Ecosystem Restoration 2021–2030 underway.

Spatiotemporal differentiation of water–carbon–light compound use efficiency and its sensitivity to the dominant factor

ABSTRACT Taking the South China karst as an example, this study constructed compound use efficiency (COM) through water, light, and carbon use efficiency (WUE, LUE, and CUE), analysed the divergence characteristics of COM, and clarified the dominant factors of COM variation and their sensitivity. It showed that from 2000 to 2018, WUE, LUE, CUE, and COM showed significant non-linear characteristics, spatially, which were distributed in a “northeast–southwest” pattern. Different factors on COM exhibited significant spatial heterogeneity. The COM first stabilized and then exhibited a fluctuating decrease with rising elevation and slope. The COM increased sharply and then slightly decreased as the temperature and precipitation increased but decreased with enhanced solar radiation and human activity intensity (HAI). HAI had the greatest effect on COM change, and the COM-HAI sensitivity first decreased and then increased; 2006 was the most abrupt year, and this may be related to the time-lagged effect of ecological restoration on vegetation.

Improving grassland ecosystem services for human wellbeing in the karst desertification control area: Anthropogenic factors become more important

Elucidating the spatial and temporal patterns of grassland ecosystem service value (ESV) changes under different karst geomorphic types (KGTs) is crucial for promoting regional sustainable development and enhancing human well-being. Karst ecosystems are characterized by high spatial heterogeneity. However, analyses of the drivers of spatial and temporal changes in ESV in karst grasslands at multiple scales are lacking. In this study, the South China Karst (SCK) region was selected as the focus area, the gross ecosystem product (GEP) accounting method was used to quantify the grassland ESV from 2000 to 2020, and the GeoDetector model was used to elucidate the spatial and temporal evolution of the GEP, the drivers, and their interactions in different KGTs. The results indicate the following: (1) Over the past 20 years, the grassland GEP of SCK has increased from ¥ 14,844.24 × 108 in 2000 to ¥ 17,174.90 × 108 in 2020. Among the various KGTs, the karst gorge exhibited the fastest GEP increase (24.93 %) and karst hilly depressions the slowest (6.22 %). (2) The karst grassland GEP showed a strong positive spatial correlation with significant clustering characteristics (p < 0.05). (3) There are significant differences in the factors influencing the GEP of grasslands with different KGT values, and although they are generally influenced by factors such as NPP, precipitation, and population density, anthropogenic factors are becoming increasingly important. In addition, the multifactor interaction explained GEP better than the single factor. Based on our findings, we propose targeted grassland ESV restoration approaches and management recommendations for various KGTs dominated by distinct factors. Our results provide a scientific basis for decision-making regarding karst ecosystem service enhancement and value realization.

Agricultural drought-driven mechanism of coupled climate and human activities in the karst basin of southern China.

Timely and accurate agricultural drought monitoring and drought-driven mechanism analysis in karst basins in the context of global warming are highly important for drought disaster monitoring and sustainable ecological development in a basin. In this study, based on MODIS data, meteorological and topographic data and land use data from 2001 to 2020, we used the Sen slope, the Mann-Kendall test and a geographic detector to explore the driving mechanisms of agricultural drought caused by climate change and human activities in the karst basin of southern China from 2001 to 2020. The results showed that (1) the spatial distribution of the TVDI in the karst basin in southern China has obvious regional characteristics, showing a decreasing trend from west to east. (2) According to the interannual trend of drought, the degree of drought in the South China karst basin exhibited a weakening trend over the last 20 years, with the most severe drought occurring in 2003. Regarding the seasonal change in the TVDI, drought in spring, summer and autumn exhibited a decreasing trend, while that in winter exhibited an increasing trend, and the drought intensity decreased in the following order: spring (0.58) > autumn (0.53) > summer (0.5) > winter (0.48). (3) Single-factor detection the results showed that rainfall, temperature and elevation were the main factors driving aridification in the study area; multifactor coupling (mean) drove drought in descending order: rainfall (q = 0.424) > temperature (q = 0.340) > elevation (q = 0.219) > land use (q = 0.188) > population density (q = 0.061) > slope (q = 0.057). Therefore, revealing the mechanism of agricultural drought in karst basins through the study of this paper has important theoretical significance and provides technical guidance for drought relief in karst areas.

Escalating hot-dry extremes in Southwest China Karst

Study regionSouthwestern China of Hubei, Hunan, Guangxi, Guangdong, Yunnan, Guizhou, Sichuan, and Chongqing. Study focusCompound hot-dry extreme events (CHDEs) are escalating disproportionately worldwide, posing significant challenges across various sectors. Yet, their driving mechanisms and characteristics at a regional scale remain largely uncertain. This study used a copula-based approach to construct the daily Standardized Compound Hot-Dry Index (SCHDI) to discern the intensifying trends of hot-dry extremes from 1963 to 2022, especially under different karst landscapes in Southwestern China. New hydrological insights for the regionSCHDI variations show an escalation of hot-dry conditions across most areas, with a notable increase in extreme hot, dry, and hot-dry events. There was a consistent increase in the frequency, duration, severity, and intensity of CHDEs, with larger magnitudes observed in non-karst areas. However, karst regions exhibited a higher escalation rate in intensity, especially over the most recent three decades. Land areas affected by less severe CHDEs (e.g., abnormal: −0.31%/year) show decreasing trends over 1993–2022, while the most extreme category (e.g., extreme: 0.34%/year) has increased. The areas affected by CHDEs showed a greater increase in trend slope compared to hot or dry events alone. Additionally, these trends are further influenced by large-scale circulation patterns. Our study highlights the role of karst landscapes in escalating hot-dry extremes in Southwestern China Karst.

Multi-elements linear discriminant analysis of herbaceous and woody plants in southwest china karst region using orthogonal partial least squares model

Multi-elements linear discriminant analysis of herbaceous and woody plants in southwest china karst region using orthogonal partial least squares model

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.

Determining rainwater dissolved organic carbon to reveal atmospheric carbon deposition in China's karst city: Variations, origins, and deposition flux

A large amount of organic carbon (OC) in the atmosphere are transferred to the Earth's surface through dry (40%) and wet (60%) deposition. Therefore, wet deposition is an important physical pathway for the removal of atmospheric OC. Identifying the variations of DOC in wet deposition (rainwater) is essential for clarifying the earth-surface C balance. The present study detected the DOC content in 96 daily rainwater samples collected over an entire year in a karst city, with abundant rainfall in Southwest China. The DOC concentrations varied between 1.03–37.7 mg C L−1, while the VWM value stood at 2.76 mg C L−1, which is similar to the worldwide and Asian averages. The yearly DOC wet deposition flux was calculated as 2.88 g C m−2 yr−1. Both the VWM concentration and flux of rainwater DOC exhibit pronounced seasonal variations and regional differences, primarily controlled by precipitation and the external input of OC. The sources of rainwater DOC were multifaceted, including urban waste emission, agricultural activities, and fossil fuel combustion (especially coal combustion), while the contribution from natural sources was limited. Additionally, the C: N (2.08) ratio of rainwater is significantly lower than the Redfield ratio (6.625), indicating the importance of considering the impact of nutrient components in rainfall on the material cycling of surface water ecosystems. This work will benefit the knowledge of the present status of rainwater DOC and its deposition flux on the karst regional scale and further on a global scale, and contribute to a better understanding of the C geochemical cycle on the territorial system.

Quantitative assessment of ecological assets in the world heritage karst sites based on remote sensing: with a special reference to South China Karst

The benefits provided by ecological assets play a crucial role in enhancing human well-being. However, there is a scarcity of viable methods for assessing their status. This study is grounded in Land Use and Land Cover Change (LUCC) and integrates both the quantity and quality aspects of these assets. Utilizing the ecological asset index (EQ and EQi), this study conducts a quantitative assessment of the assets in the Shibing karst and the Libo-Huanjiang karst heritage sites, while also qualitatively analyzing their influencing factors. The findings reveal that: (1) In the Shibing heritage site, forest and impervious surface assets exhibited an upward trend, whereas cropland and grassland experienced a decline; meanwhile, shrub and water body assets remained relatively stable. The total area of assets rated as excellent or good increased by 95.371 km2, resulting in an EQ enhancement of 45.427. (2) Likewise, in the Libo-Huanjiang heritage site, forest and impervious surface assets demonstrated an upward trajectory, while shrub assets declined. Cropland, grassland, and water body assets experienced minimal variation. The total area of assets rated as excellent or good expanded by 168.227 km2, resulting in an EQ enhancement of 80.806. (3) The execution of a series of ecological protection projects and management plans for heritage site conservation primarily accounts for the enhancement of regional assets. Notably, ecological resources, socio-economic conditions, human resources, and conservation management policies serve as pivotal drivers influencing the alterations in heritage site assets.

Spatial Pattern of Ecosystem Services and the Mechanism of Eco-Industry Formation in South China Karst Nature Reserves

Karst nature reserve (NR) ecosystems are vulnerable, and the development of regulatory and cultural services industries is still in its infancy. Realization of ecological product value (EPV) is a crucial way to promote the integration of eco-protection and industrial development in nature reserves (NRs). This study calculates EPV using a modified equivalent factor, analyzes the spatial pattern of EPV using the fishnet tool in Arc GIS, and constructs a model for realizing EPV. Finally, the driving factors for the formation of eco-industry are identified using the grey correlation analysis (GCA) method. The results show that (1) the regulatory service products in karst NRs play a decisive role in EPV, and forest ecosystems have significant EPV potential; (2) high-value grids are concentrated in the core and buffer zones of karst NRs and the spatial distribution of EPV in the experimental zone is highly heterogeneous, with high and low-value grids in mixed distribution; (3) the realization model of EPV in karst NRs follows the logic of “preservation, transformation, and appreciation”; (4) human resources (0.813), ecology (0.798), industry (0.693), policy (0.783), the market (0.778), and economy (0.715) are essential drivers for the formation of eco-industry in karst NRs. Overall, karst NRs can promote the realization of EPV through planning and regulation of land use, based on the interaction between internal and external factors, to promote the coordinated development of eco-industry in karst NRs. This study provides a reference for the scientific management of eco-resources and the sustainable development of eco-industry in karst NRs.

Assessing rainfall erosivity changes over China through a Bayesian averaged ensemble of high-resolution climate models

Spatiotemporal variation in rainfall erosivity resulting from changes in rainfall characteristics due to climate change has implications for soil erosion in developing countries. To promote soil and water conservation planning, it is essential to understand past and future changes in rainfall erosivity and their implications on a national scale. In this study, we present an approach that uses a Bayesian model averaging (BMA) method to merge multiple regional climate models (RCMs), thereby improving the reliability of climate-induced rainfall erosivity projections. Our multi-climate model and multi-emission scenario approach utilize five RCMs and two Representative Concentration Pathways (RCP4.5 and RCP8.5) scenarios for the baseline period (1986–2005) and future periods (2071–2090) to characterize the spatiotemporal projection of rainfall erosivity and assess variations in China. Our results indicate that the two models outperform other models in reproducing the spatial distribution and annual cycle of rainfall erosivity in China. Moreover, we found an increasing trend in the annual rainfall erosivity from the baseline climate up to the RCMs for all models, with an average change in erosivity of approximately 10.9% and 14.6% under RCP4.5 and RCP8.5, respectively. Our BMA results showed an increase in the absolute value of rainfall erosivity by 463.3 and 677.0 MJ·mm·hm−2·h−1, respectively, in the South China red soil region and the Southwest China karst region under the RCP8.5 scenario. This increase indicates that climate warming will significantly enhance the potential erosion capacity of rainfall in these regions. Additionally, our study revealed that the Southwest China karst region and the Northwest China Loess Plateau region are more sensitive to radiation forcing. To mitigate the risk of soil erosion caused by climate change, it is necessary to consider changes in rainfall erosivity, local soil conditions, vegetation coverage, and other factors in different regions and take appropriate soil and water conservation measures.

Terrestrial algae: pioneer organisms of carbonate rock solutional weathering in South China karst.

The formation of soil in karst ecosystem has always been a scientific problem of great concern to human beings. Algae can grow on the exposed and non-nutrition carbonate surface, inducing and accelerating weathering of rock substrates, thus promoting soil formation. Yet the actual contribution of algae to solutional weathering intensity remains unclear. In this study, we performed weathering simulation experiment on two algae species (Klebsormidium dissectum (F.Gay) H.Ettl & G.Gärtner and Chlorella vulgaris Beijerinck), which were screened from carbonated rock surfaces from a typical karst region in South China. The results showed: (1) both algae have solutional weathering effect on carbonate rock, (2) there is no difference of solutional intensity observed, yet the solutional modes are different, suggesting different ecological adaptative strategies, (3) algae on carbonate rocks have higher carbonic anhydrase activity (CAA) and secrete more extracellular polysaccharide (EPS), accelerating rock weathering. (4) The absolute dissolution amount of carbonate rock with algae participation is 3 times of that of without algae. These results indicate the significant impact of terrestrial algae on carbonate rock solutional weathering and provides quantitative evidence that terrestrial algae are pioneer species. It also contributes to our further understanding of soil formation in karst ecosystems in South China.

Ecosystem Services Value Realization and Ecological Industry Design in Scenic Areas of Karst in South China

Ecosystem services (ESs) value realization and ecological industry (eco-industry) are essential components of regional development. Due to the vulnerability and non-renewability of natural landscape resources in Karst areas, once unreasonable resource development takes place, it is easy to pose threats and causes damage to its ecosystem. This article selects the grain data correction equivalent factor coefficients in Guizhou Province, China, and establishes accounting indicators for Karst scenic areas. It is found that the total economic value of ESs is as follows: Shanmuhe Scenic Area (CNY 5096.3 thousand) &gt; DaXiaoQiKong Scenic Area (CNY 2778.6 thousand) &gt; Huangguoshu Scenic Area (CNY 2130.7 thousand). Among them, the value of regulating services plays a dominant role in the composition of ESs, and the value of forests accounts for the largest proportion. Through web crawlers, tourism data can be acquired, and the Product–Experience–Feedback–Improvement (PEFI) model can be applied to reveal that tourists have a predominantly positive perception of Karst scenic areas. This indicates that karst landscape resources are deeply loved by domestic and foreign tourists, especially mountain, water and forest landscapes. Based on the results of the ES value accounting of the scenic area and the external perception data of tourists towards the scenic area, the eco-industry spatial layout development plan is formulated. According to local conditions, the development, construction, and protection of the scenic area are carried out, jointly promoting the realization of the ecological product value (EPV) of the Karst scenic area, to determine the optimal development direction of the eco-industry, and to promote the coordinated development of ecological resources and assets.

Bedrock regulated climatic controls on the interannual variation of land sink in South-West China karst through soil water availability

South-West China (SWC) is a pivotal region for global greening, recognized as having great carbon sink potential. Multiple evidence underscores the expanding contribution of SWC’s carbon sink to the global carbon sink enhancement. However, our understanding of carbon sink dynamics and the response to climate across bedrock remains limited. In this study, we investigated the divergence in trends in carbon sink across bedrocks, evaluating their respective contributions of bedrocks to the overall carbon sink in SWC. Additionally, we assessed the dominant climatic factors and examined how bedrocks shape the response of carbon sink to climate change. Our results revealed a notable increase in the regional carbon sink, with an average rate of 3.58 TgC/yr from 1981 to 2019. Continuous Carbonate Rocks (CCR) exhibited the highest increased rate of total carbon sequestration (1.57 TgC/yr), surpassing Discontinuous Carbonate Rocks (DCR) by threefold. Non-karst areas contributed the most to both the mean and interannual variations of the overall carbon sink, with CCR exerting the most contribution to the trends. Over time, the contribution of CCR to the overall carbon sink escalated, while the contributions of DCR and non-karst declined. All bedrocks displayed negative correlations between NEP and temperature, with DCR showing higher susceptibility. Non-karst areas experienced adverse impacts from vapor pressure deficit, while CCR benefited from positive soil moisture effects. Our findings implied that bedrock indeed played a critical role in the variations in NEP and the response of NEP to climate change. Bedrock regulated climatic controls on carbon sink through soil water availability as soil water availability is affected by the lithology of basement carbonate. This novel understanding emphasizes the necessity for tailored ecological restoration initiatives that consider the distinctive lithological features of the karst ecosystem, and holds significance for implementing ecologically sound projects in karst regions.

PhytOC sequestration characteristics and phytolith carbon sink potential of karst Masson pine forest in southern China

Masson pine forest is an extremely important component of terrestrial ecosystems and plays a significant ecological function in forest carbon sink in China. Phytolith-occluded organic carbon (PhytOC) is the important long-term stable carbon sink mechanism in terrestrial ecosystems. To provide scientific bases for the accurate estimation of phytolith carbon sink and precise management of Masson pine forests, PhytOC sequestration and accumulation of the three typical forest ages of Masson pine in southern China karst area were studied in the present study. Although the sampling pots were still limited, PhytOC sequestration characteristics of the Masson pine forests were successfully clarified. The followed results and conclusions were obtained: 1) The range of PhytOC content, reserves, and sequestration rate of the Masson pine forests was 0.04–0.78 g·kg−1, 0.44–16.93 kg·hm−2, and 0.094–2.557 kg CO2 hm−2·a−1, respectively. 2) Among the three forest ages of Masson pine, the mature forest had the highest accumulation of PhytOC, and the middle-aged forest had the highest sequestration rate of PhytOC. Compared with biomass, vegetation productivity more positively significantly affected the PhytOC sequestration. 3) Among the three organs, leaves had the highest PhytOC content and trunks had the highest PhytOC reserves, which all took significant functions in the sequestration and accumulation of PhytOC. 4) Artificial measures to promote vegetation productivity, such as thinning, artificial tending, and low-efficiency forest transformation, will significantly increase the PhytOC sequestration and accumulation of Masson pine forests.

Assessing and decoupling ecosystem services evolution in karst areas: A multi-model approach to support land management decision-making

Incorporating Ecosystem Service Value (ESV) into land use planning provides a fresh perspective for informed land management decisions. ESV, influenced by socio-economic and natural factors, has complex driving mechanisms, particularly in China's southwestern karst regions. Studying mediating variables helps elucidate these mechanisms. Further research into ecosystem services interactions and effective land use policies in karst areas is needed. This study evaluates the ESV of Guizhou Province, located in southern China's karst region, using the benefit transfer approach. Combining the Guizhou Provincial Land Use Planning Outline (2006–2020) with the multi-objective programming (MOP) model optimized by genetic algorithm and the patch-generating land use simulation (PLUS) model, four future development scenarios were designed. The response of ESV to land use and land cover (LULC) changes at the county scale under four different development scenarios from 2000 to 2020 and in the future was analyzed. A partial least squares structural equation model (PLS-SEM) was used to decouple the driving mechanism affecting ESV. The results show that over the past two decades, with the implementation of various ecological restoration projects, the total ESV has increased. The ESV for natural development scenarios, ecological conservation scenarios, economic development scenarios, and sustainable development scenarios are CNY 238.278 billion, CNY 400.514 billion, CNY 283.201 billion, and CNY 323.615 billion, respectively. The direct impacts of karst surface characteristic factors (KSCF), meteorological factors (MF), socio-economic factors (SEF) and transportation location factors (TLF) on ESV are positive (0.098), negative (−0.098), positive (0.336), and positive (0.109) respectively. The total effect of KSCF on ESV through influencing socio-economic factors and LULC is (−0.738), with SEF playing a complete mediating role. MF indirectly affect ESV by influencing LULC, with LULC playing a complete mediating role in this process. The PLS-SEM model shows that under the dominant position of LULC, the interaction between natural environmental factors and socio-economic factors on ESV is very complex. This study offers valuable insights that can guide managers in this region, as well as in other karst regions globally, in the development of sustainable land use policies.

A New Advance on the Improvement of Forest Ecosystem Functions in the Karst Desertification Control

In recent years, after the implementation of large-scale ecological restoration projects, karst areas in the South China Karst have become global “greening” hot spots. However, the biodiversity, ecosystem quality, and security patterns in karst areas are still severely affected. The reason for this is that despite the execution of karst desertification control projects, the lag mechanism of forest ecosystem functions and services is still unclear. Therefore, we analyze the progress in the research related to desertification control and the improvement of regional forest ecosystem function through a systematic literature review approach. The results show that the major landmarks achieved so far include the following aspects: based on the karst desertification control area, we have elucidated the driving factors of forest ecosystem change, discovered the ecological security pattern of landscape optimization and reconstruction, revealed the internal mechanism of forest system structure optimization and stability enhancement, overcome the technical constraints of forest water–fertilizer coupling, introduced a strategy for regulating functional traits to improve the growth and development of vegetation, proposed strategies to enhance carbon sequestration in forests and the efficiency of microbial carbon use, and created models and paths to realize the value of forest products. The key scientific issues to be addressed in the future mainly comprise the following: the effects of spatial heterogeneity on forest ecosystems, disturbances in landscape reconfiguration caused by human activities, the work mechanisms of the combination and configuration of the niche in structural optimization, the response of species configuration to the water cycle, the coupled relationship between biodiversity and soil properties, the screening and construction of the plant germplasm resource base, the functional trade-offs/synergistic mechanisms of karst forest ecosystems, the creation of policies for forest product in terms of rights, trading, and compensation, and systematic research on the extended industrial chain of forest ecosystems, its service potential, and so on.

Synergy and regulation of the South China Karst WH site integrity protection and the buffer zone agroforestry development

The Natural World Heritage site (NWH) has a dual role of protection and utilization. The buffer zone of the South China Karst (SCK) World Heritage (WH) site is scattered with village dwellings, which adds pressure to preserve the outstanding universal value (OUV) and integrity protection of the WH site. The development of agroforestry is an essential means to maintain rural livelihoods, protect the ecological environment, and realize the protection and development of the heritage site. Studying the synergy and regulation of the heritage site integrity protection and the buffer zone agroforestry development is essential. This study takes the Shibing and Libo–Huanjiang karst WH as the study areas and administrative villages as the evaluation unit. From 2020 to 2023, through data methods such as remote sensing data interpretation, information data survey and collection, comprehensive index analysis, coupling coordination degree model, and GIS spatial analysis, a systematic study was conducted on the basic frontier research, synergy relationship, and regulation of the heritage site integrity protection and the buffer zone agroforestry development. The results demonstrate that the Shibing and Libo–Huanjiang karst WH sites integrity protection and agroforestry development in the buffer zone have a high coupling degree and a good coupling coordination relationship. This reveals that the heritage site integrity protection and the buffer zone agroforestry development are an interconnected and mutually influential whole, which the synergistic relationship between them is developing in a positive direction; The buffer zone agroforestry development lags behind the heritage site integrity protection, based on which proposed the regulatory measures for the synergy development of the heritage site integrity protection and agroforestry development in the buffer zone. The findings in this study provide references for the synergies development of the WH karst site integrity protection and agroforestry development in the buffer zone.