By selecting a typical peak-cluster depression area of karst region in Southwest China, we evaluated the effect of land use types and topographic factors on soil nutrients. Grid and line sampling methods were used to ...By selecting a typical peak-cluster depression area of karst region in Southwest China, we evaluated the effect of land use types and topographic factors on soil nutrients. Grid and line sampling methods were used to sample soil in depression and slope lands respectively, and classical statistical tools were applied to analyze the spatial variability character of soil organic carbon （SOC）, total nitrogen （TN）, total phosphorus （TP）, total potassium （TK）, available nitrogen （AN）, available phosphorus （AP）, available potassium （AK）, pH, and C/N. It was found that land use type was the dominant factor that effected the spatial heterogeneity of SOC, TN, TP, TK, AN, and AP. The content of SOC, TN, and AN decreased with the increase of land use intensity. Due to high fertilizer input, TP and AP in tillage fields were higher than those in the other land use types. TK had no obvious change trend among various land use types. Topographic factors had a significant effect on SOC, TN, TP, AN, AP, AK, and pH. Habitat factor was the dominant factor that effected AK. Altitude factor was the dominant factor for pH. However, all of these factors had no significant effect on C/N. Tillage practice had important effect on soil nutrients loss and soil degradation in the fragile karst ecosystem, and the input of organic manure should be increased in this region.展开更多
Through utilizing water flow monitoring, rock scratching, soil wood piles and radionuclide ^(137)Cs tracing in the Longhe karst ecological experimental site(hereinafter referred to"Longhe site"), Pingguo Cou...Through utilizing water flow monitoring, rock scratching, soil wood piles and radionuclide ^(137)Cs tracing in the Longhe karst ecological experimental site(hereinafter referred to"Longhe site"), Pingguo County, Guangxi Province, the features and values of soil erosion and soil leakage in different geomorphologic locations and land uses in the karst peak-cluster depressions are showed clearly. There are four kinds of geomorphologic locations in the karst peak-cluster depression, namely peaks, strip, slopes and depression. The soil leakage modulus in the peaks and strips respectively occupy 92.43% and 96.24% of the total mean soil erosion modulus at experimental sites. On the slope, soil leakage accounted for about 75%. At the bottom of depression, surface water was the main factor of soil erosion, and at last most soil leaked into underground rivers from sinkholes. The total soil erosion modulus and the contribution rates of relative surface soil erosion in regard of peaks, slopes and depressions gradually increased. There are also five major types of land use in the karst peak-cluster depressions, farmland, Kudingcha tea plantations, young Lignum Sappan fields, shrub-grassland and pastures. The soil erosion modulus of slope farmland has the highest value with an increasing trend year by year. But soil erosion modulus of other four land use types decreased by year, which shows the "grain for green" will result in better soil protection. By handling with rocky desertification and ecological rehabilitation in Longhe site, the mean soil erosion modulus of the karst peak-cluster depression has decreased about 80% from 2003 to 2015.展开更多
Karst environmental issues have become one of the hot spots in contemporary international geological research. The same problem of water shortage is one of the hot spots of global concern. The peak-cluster depression ...Karst environmental issues have become one of the hot spots in contemporary international geological research. The same problem of water shortage is one of the hot spots of global concern. The peak-cluster depression basins in southwest of Guangxi is an important water connotation and ecological barrier areas in the Pearl River Basin of China. Thus, studying the spatial and temporal variations and the influencing factors of its water yield services is critical to achieve the sustainable development of water resources and ecological environmental protection in this region. As such, this paper uses the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST) model to assess the spatial and temporal variabilities of water yield services and its trends in the peak-cluster depression basins in southwest of Guangxi from 2000 to 2020. This work also integrates precipitation(Pre), reference evapotranspiration(ET), temperature(Tem), digital elevation model(DEM), slope, normalized difference vegetation index(NDVI), land use/land cover(LULC) and soil type to reveal the main factors that influence water yield services with the help of Geodetector. Results show that: 1) in time scale,the total annual water yield in the study area show a fluctuating and increasing trend from 2000 to 2020, with a growth rate of 7.3753 × 10^(8)m^(3)/yr, and its multi-year average water yield was 538.07 mm;2) in spatial pattern, with high yield areas mainly distributed in the south of the study area(mainly including Shangsi County, Pingxiang City, Ningming County, Longzhou County and Jingxi County), and low yield areas mainly distributed in Baise City and Nanning City;3) the dominant factor of water yield within karst and non-karst landforms is not necessarily controlled by precipitation, and the explanation degree of DEM factors in karst areas is significantly higher than that in non-karst areas;4) amongst the climatic factors, Pre, ET and Tem are dominant in the spatial pattern of region water yield capacity. among which Pre has the highest explanatory power for the spatial heterogeneity of annual water production, with q values above0.8, and each driver showed a significant interaction on the spatial distribution of water yield, with Pre exhibiting the strongest interaction with LULC.展开更多
Scientific understanding of the trade-offs between services is crucial for the scientific management and protection of ecosys-tems and the formulation of resource management policies.This study integrated meteorologic...Scientific understanding of the trade-offs between services is crucial for the scientific management and protection of ecosys-tems and the formulation of resource management policies.This study integrated meteorological,land use,and soil data to assess the ecosystem services,namely,water yield(WY),soil erosion(SE),and carbon sinks(CS),in peak-cluster depression basins on the Sino-Vietnamese border in China during 2000-2020.It analyzed the trade-offs and synergistic relationships among the three ecosystem ser-vices and their time-lag effects and driving mechanisms with the help of pixel-by-pixel time-lag intercorrelation and geographical de-tector methods.Results show that:1)from 2000 to 2020,the key ecosystem service indicators in the peak-cluster depression basins on the Sino-Vietnamese border in China demonstrated a significant and synergistic trend of positive change.The WY increased at a rate of 11.99 mm/yr,CS increased at a rate of 2.44 g C/(m^(2)∙yr),and SE decreased at a rate of 0.06 t/(ha∙yr).2)Most areas showed a synergistic relationship across the three ecosystem services,and the areas with a trade-off relationship were mostly concentrated in Baise City and the southwest of Chongzuo City,Guangxi.3)The time-lag effect between SE and WY was mostly concentrated in 0 yr,that between SE and CS was mostly concentrated in 5 yr,and that between CS and WY was mostly concentrated in 1 yr.4)Population density was the controlling factor between SE and WY.Vegetation coverage factor is the main controlling factor between SE and CS.The lithologic factor is the main controlling factor between CS and WY.Studying the trade-off relationship of ecosystem services at spatial and tem-poral scales on the Sino-Vietnamese border in China karst areas can provide a basis for regional ecological construction and develop-ment strategies,and it is conducive to meeting regional interest needs,maximizing comprehensive benefits,balancing the ecological en-vironment,and achieving regional sustainable development.展开更多
Under the background of large-scale ecological restoration, China's southwestern karst region has become a hotspot of global vegetation cover “greening” in the past 20 years. However, because of geological const...Under the background of large-scale ecological restoration, China's southwestern karst region has become a hotspot of global vegetation cover “greening” in the past 20 years. However, because of geological constraints, it is difficult to restore the forest landscapes in some areas. It is urgent to understand the impacts of human disturbances during the historical period on the difficult-to-forestation rocky-desertification areas of the karst region in order to guide future afforestation. In this study, we quantified the changes of specific sediment yield in typical karst depressions over the past 500 years by using ^(137)Cs,^(210)Pb, and ^(14)C dating methods in karst depressions, and identified the main human disturbances related to historical erosion and sedimentation by combining with historical data. The results showed that the erosion and sedimentation of the three depressions in 1921–1963 were significantly higher than that in 1963–2021, and the sedimentation rate(0.64–1.33 cm a^(-1)) and the specific sediment yield(2.51–13.11 t ha^(-1)a^(-1)) during Ming and Qing dynasties(1504–1812) were higher than the sedimentation rate(0.26–0.95 cm a^(-1)) and specific sediment yield(0.95–6.99 t ha^(-1)a^(-1)) in the recent century(1921–2021). Reconstruction data and literature from the Ming and Qing dynasties show an empirical link between changes in population, arable land, food, forest area,and deforestation events during the same period. It was found that the population and arable land in Guangxi increased more than three-fold and the forest area decreased significantly in the 17th century after the migration of the Yao ethnic group and the introduction of maize to the region, which may be the main reason for intensifying the erosion of depressions. This study is of great significance to understanding the evolution history of rocky desertification in this region and to answer the potential of afforestation.展开更多
结合自然邻居搜索算法改进了密度峰值聚类(clustering by fast search and find of density peaks,CFSFDP)算法存在的一系列问题,提出基于自然邻居搜索优化策略的密度峰值聚类(density peak clustering algorithm optimized by natural ...结合自然邻居搜索算法改进了密度峰值聚类(clustering by fast search and find of density peaks,CFSFDP)算法存在的一系列问题,提出基于自然邻居搜索优化策略的密度峰值聚类(density peak clustering algorithm optimized by natural neighbor search,NaN-CFSFDP)算法。基于自然邻居搜索算法提出了一种离群样本的检测方法,针对CFSFDP算法中截断距离d_(c)人工准确取值较难的问题,结合自然邻居搜索算法改进了d_(c)的计算方式,实现了d_(c)的自动取值。重新设计并统一了CFSFDP算法的样本密度度量规则,使其更关注每个样本的局部信息。由于数据集中因类簇间的密度差异大,密度峰值点集中于稠密簇使得簇丢失,因此提出样本共享自然邻居和类簇共享自然邻居的概念,构造新的类簇融合算法。合成数据集和真实数据集上的实验结果表明,在大多数情况下,NaN-CFSFDP算法在聚类性能上优于或至少与比较方法相当,且与CFSFDP算法及其改进算法相比参数更少。展开更多
文摘By selecting a typical peak-cluster depression area of karst region in Southwest China, we evaluated the effect of land use types and topographic factors on soil nutrients. Grid and line sampling methods were used to sample soil in depression and slope lands respectively, and classical statistical tools were applied to analyze the spatial variability character of soil organic carbon （SOC）, total nitrogen （TN）, total phosphorus （TP）, total potassium （TK）, available nitrogen （AN）, available phosphorus （AP）, available potassium （AK）, pH, and C/N. It was found that land use type was the dominant factor that effected the spatial heterogeneity of SOC, TN, TP, TK, AN, and AP. The content of SOC, TN, and AN decreased with the increase of land use intensity. Due to high fertilizer input, TP and AP in tillage fields were higher than those in the other land use types. TK had no obvious change trend among various land use types. Topographic factors had a significant effect on SOC, TN, TP, AN, AP, AK, and pH. Habitat factor was the dominant factor that effected AK. Altitude factor was the dominant factor for pH. However, all of these factors had no significant effect on C/N. Tillage practice had important effect on soil nutrients loss and soil degradation in the fragile karst ecosystem, and the input of organic manure should be increased in this region.
基金the financial support by IGCP 661, CAGS Research Fund (Grant No. YYWF201725)the National Natural Science Foundation of China (Grant No.41571203)+1 种基金the Ministry of Science and Technology of China (Grant No. 2016YFC0502403-2) the Bureau of Science and Technology of Guangxi (Grant No. 2014GXNS FAA118280)
文摘Through utilizing water flow monitoring, rock scratching, soil wood piles and radionuclide ^(137)Cs tracing in the Longhe karst ecological experimental site(hereinafter referred to"Longhe site"), Pingguo County, Guangxi Province, the features and values of soil erosion and soil leakage in different geomorphologic locations and land uses in the karst peak-cluster depressions are showed clearly. There are four kinds of geomorphologic locations in the karst peak-cluster depression, namely peaks, strip, slopes and depression. The soil leakage modulus in the peaks and strips respectively occupy 92.43% and 96.24% of the total mean soil erosion modulus at experimental sites. On the slope, soil leakage accounted for about 75%. At the bottom of depression, surface water was the main factor of soil erosion, and at last most soil leaked into underground rivers from sinkholes. The total soil erosion modulus and the contribution rates of relative surface soil erosion in regard of peaks, slopes and depressions gradually increased. There are also five major types of land use in the karst peak-cluster depressions, farmland, Kudingcha tea plantations, young Lignum Sappan fields, shrub-grassland and pastures. The soil erosion modulus of slope farmland has the highest value with an increasing trend year by year. But soil erosion modulus of other four land use types decreased by year, which shows the "grain for green" will result in better soil protection. By handling with rocky desertification and ecological rehabilitation in Longhe site, the mean soil erosion modulus of the karst peak-cluster depression has decreased about 80% from 2003 to 2015.
基金Under the auspices of National Natural Science Foundation of China (No. 42061020)Natural Science Foundation of Guangxi Zhuang Autonomous Region (No. 2018JJA150135)+3 种基金Guangxi Key Research and Development Program (No. AA18118038)Science and Technology Department of Guangxi Zhuang Autonomous Region (No. 2019AC20088)The Program of Improving the Basic Research Ability of Young and Middle-aged Teachers in Guangxi Universities (No. 2021KY0431)High Level Talent Introduction Project of Beibu Gulf University (No. 2019KYQD28)。
文摘Karst environmental issues have become one of the hot spots in contemporary international geological research. The same problem of water shortage is one of the hot spots of global concern. The peak-cluster depression basins in southwest of Guangxi is an important water connotation and ecological barrier areas in the Pearl River Basin of China. Thus, studying the spatial and temporal variations and the influencing factors of its water yield services is critical to achieve the sustainable development of water resources and ecological environmental protection in this region. As such, this paper uses the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST) model to assess the spatial and temporal variabilities of water yield services and its trends in the peak-cluster depression basins in southwest of Guangxi from 2000 to 2020. This work also integrates precipitation(Pre), reference evapotranspiration(ET), temperature(Tem), digital elevation model(DEM), slope, normalized difference vegetation index(NDVI), land use/land cover(LULC) and soil type to reveal the main factors that influence water yield services with the help of Geodetector. Results show that: 1) in time scale,the total annual water yield in the study area show a fluctuating and increasing trend from 2000 to 2020, with a growth rate of 7.3753 × 10^(8)m^(3)/yr, and its multi-year average water yield was 538.07 mm;2) in spatial pattern, with high yield areas mainly distributed in the south of the study area(mainly including Shangsi County, Pingxiang City, Ningming County, Longzhou County and Jingxi County), and low yield areas mainly distributed in Baise City and Nanning City;3) the dominant factor of water yield within karst and non-karst landforms is not necessarily controlled by precipitation, and the explanation degree of DEM factors in karst areas is significantly higher than that in non-karst areas;4) amongst the climatic factors, Pre, ET and Tem are dominant in the spatial pattern of region water yield capacity. among which Pre has the highest explanatory power for the spatial heterogeneity of annual water production, with q values above0.8, and each driver showed a significant interaction on the spatial distribution of water yield, with Pre exhibiting the strongest interaction with LULC.
基金Under the auspices of National Natural Science Foundation of China(No.42061020)Natural Science Foundation of Guangxi Zhuang Autonomous Region(No.2018JJA150135)+2 种基金Guangxi Key Research and Development Program(No.AA18118038)Science and Technology Department of Guangxi Zhuang Autonomous Region(No.2019AC20088)High Level Talent Introduction Project of Beibu Gulf University(No.2019KYQD28)。
文摘Scientific understanding of the trade-offs between services is crucial for the scientific management and protection of ecosys-tems and the formulation of resource management policies.This study integrated meteorological,land use,and soil data to assess the ecosystem services,namely,water yield(WY),soil erosion(SE),and carbon sinks(CS),in peak-cluster depression basins on the Sino-Vietnamese border in China during 2000-2020.It analyzed the trade-offs and synergistic relationships among the three ecosystem ser-vices and their time-lag effects and driving mechanisms with the help of pixel-by-pixel time-lag intercorrelation and geographical de-tector methods.Results show that:1)from 2000 to 2020,the key ecosystem service indicators in the peak-cluster depression basins on the Sino-Vietnamese border in China demonstrated a significant and synergistic trend of positive change.The WY increased at a rate of 11.99 mm/yr,CS increased at a rate of 2.44 g C/(m^(2)∙yr),and SE decreased at a rate of 0.06 t/(ha∙yr).2)Most areas showed a synergistic relationship across the three ecosystem services,and the areas with a trade-off relationship were mostly concentrated in Baise City and the southwest of Chongzuo City,Guangxi.3)The time-lag effect between SE and WY was mostly concentrated in 0 yr,that between SE and CS was mostly concentrated in 5 yr,and that between CS and WY was mostly concentrated in 1 yr.4)Population density was the controlling factor between SE and WY.Vegetation coverage factor is the main controlling factor between SE and CS.The lithologic factor is the main controlling factor between CS and WY.Studying the trade-off relationship of ecosystem services at spatial and tem-poral scales on the Sino-Vietnamese border in China karst areas can provide a basis for regional ecological construction and develop-ment strategies,and it is conducive to meeting regional interest needs,maximizing comprehensive benefits,balancing the ecological en-vironment,and achieving regional sustainable development.
基金supported by the National Natural Science Foundation of China (Grant Nos. U20A2048 & 41930652)the National Key Research and Development Program of China (Grant No. 2022YFF1300700)。
文摘Under the background of large-scale ecological restoration, China's southwestern karst region has become a hotspot of global vegetation cover “greening” in the past 20 years. However, because of geological constraints, it is difficult to restore the forest landscapes in some areas. It is urgent to understand the impacts of human disturbances during the historical period on the difficult-to-forestation rocky-desertification areas of the karst region in order to guide future afforestation. In this study, we quantified the changes of specific sediment yield in typical karst depressions over the past 500 years by using ^(137)Cs,^(210)Pb, and ^(14)C dating methods in karst depressions, and identified the main human disturbances related to historical erosion and sedimentation by combining with historical data. The results showed that the erosion and sedimentation of the three depressions in 1921–1963 were significantly higher than that in 1963–2021, and the sedimentation rate(0.64–1.33 cm a^(-1)) and the specific sediment yield(2.51–13.11 t ha^(-1)a^(-1)) during Ming and Qing dynasties(1504–1812) were higher than the sedimentation rate(0.26–0.95 cm a^(-1)) and specific sediment yield(0.95–6.99 t ha^(-1)a^(-1)) in the recent century(1921–2021). Reconstruction data and literature from the Ming and Qing dynasties show an empirical link between changes in population, arable land, food, forest area,and deforestation events during the same period. It was found that the population and arable land in Guangxi increased more than three-fold and the forest area decreased significantly in the 17th century after the migration of the Yao ethnic group and the introduction of maize to the region, which may be the main reason for intensifying the erosion of depressions. This study is of great significance to understanding the evolution history of rocky desertification in this region and to answer the potential of afforestation.
文摘结合自然邻居搜索算法改进了密度峰值聚类(clustering by fast search and find of density peaks,CFSFDP)算法存在的一系列问题,提出基于自然邻居搜索优化策略的密度峰值聚类(density peak clustering algorithm optimized by natural neighbor search,NaN-CFSFDP)算法。基于自然邻居搜索算法提出了一种离群样本的检测方法,针对CFSFDP算法中截断距离d_(c)人工准确取值较难的问题,结合自然邻居搜索算法改进了d_(c)的计算方式,实现了d_(c)的自动取值。重新设计并统一了CFSFDP算法的样本密度度量规则,使其更关注每个样本的局部信息。由于数据集中因类簇间的密度差异大,密度峰值点集中于稠密簇使得簇丢失,因此提出样本共享自然邻居和类簇共享自然邻居的概念,构造新的类簇融合算法。合成数据集和真实数据集上的实验结果表明,在大多数情况下,NaN-CFSFDP算法在聚类性能上优于或至少与比较方法相当,且与CFSFDP算法及其改进算法相比参数更少。
