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Health Assessment of the Baitiao-Fu River Based on Ecological Integrity and Social Service Functions
XI Haojun, YUAN Yibin, ZAN Xiaohui, LI Tianhong
Acta Scientiarum Naturalium Universitatis Pekinensis    2022, 58 (6): 1111-1120.   DOI: 10.13209/j.0479-8023.2022.104
Abstract384)   HTML    PDF(pc) (1102KB)(183)       Save
The Baitiao-Fu River, a typical tributary of Jinjiang River in Chengdu City of China, was selected to perform the health assessment based on ecological integrity and social service functions. Therein, 16 specific indicators from three aspects including habitat characteristics, biological community and social service were selected to establish a river health assessment system for meeting the needs of river ecosystem integrity and human services. Field investigation, remote sensing and GIS, environmental DNA, and statistical method were used to quantify these indicators, and the comprehensive assessment method was applied to four river segments to calculate the river health assessment index (RHI). The results showed that all RHIs of these tributaries ranged from 3.23 to 3.82, suggesting the sub-healthy level. The river health status was generally good in the upper reaches, whereas that was relatively poor in the middle and lower reaches, which presented strong spatial heterogeneity, and reflected that the health of river system might be affected by human activities. The results provide a scientific basis for the sustainable management of rivers in Chengdu Plain, and contribute a method for health assessment of river ecosystems affected by human activities.
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Forecasting Spatial Pattern of Land Use Change in Rapidly Urbanized Regions Based on SD-CA Model
HU Yeting, LI Tianhong
Acta Scientiarum Naturalium Universitatis Pekinensis    2022, 58 (2): 372-382.   DOI: 10.13209/j.0479-8023.2022.005
Abstract667)   HTML    PDF(pc) (11852KB)(153)       Save
As the method in the Future Land Use Simulation (FLUS) model, System Dynamics (SD) and Cellular Automata (CA) are used to explore the spatiotemporal change features of land use in Shenzhen City, a typical rapidly urbanized region. Future land use demand was obtained by using SD model based on historical data from 2004 to 2018 for the use of spatial prediction. Then, CA model was used to predict the spatial distribution of eight land types (cropland, scrub, forest, grassland, urban land, traffic land, water area, and other land) in 2025 based on the 2014 land use map and the dynamic change of land use was analyzed. The simulation accuracy of land use pattern containing multiple land types in different time periods was relatively reliable, indicating that the SD-CA coupling model could be used to simulate the spatial patterns of land use in regions undergoing drastic changes of multiple land types. It was estimated that the percentage decline of the area of cropland, scrub, forest, grassland, and water in 2025, would reach to 39.26%, 32.72%, 10.06%, 55.3%, and 16.93%, respectively compared with that in 2014. The proportion of construction land (urban land and traffic land) area would account for more than half. The distribution of natural land types would become more fragmented and discrete while construction land would be continuously expanded and internally connected by encroaching on the ecological land. The results could provide support for land planning and evaluation of ecological and environmental effects from land use change in Shenzhen City.
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Ecological Waterway Assessment of Wuhan-Anqing Reach of the Yangtze River
LIU Nian, LI Tianhong, KUANG Shuya
Acta Scientiarum Naturalium Universitatis Pekinensis    2021, 57 (3): 489-495.   DOI: 10.13209/j.0479-8023.2021.022
Abstract555)   HTML    PDF(pc) (12926KB)(659)       Save
Based on the principle of the harmonious relationship between navigation and river ecosystem protection, an evaluation indicator system for Wuhan-Anqing Reach in the middle-lower of the Yangtze River was constructed. With analytic hierarchy process (AHP) and the comprehensive evaluation index method considering the bucket effect of individual function to the whole system health, the ecological health condition of Wuhan-Anqing Reach in the year of 2018 was evaluated. The results showed that the waterway health index was 0.8145, indicating a fair level. The self-purification function graded excellent, and the navigation function, flood discharging function as well as landscape & entertainment function were good, while the ecological function was poor. The results suggested that ecological protection and rehabilitation should be strengthened in the process of future waterway regulation projects.
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Changes of Spatial Variations in Ecosystem Service Value in China
CHEN Juncheng, LI Tianhong
Acta Scientiarum Naturalium Universitatis Pekinensis    2019, 55 (5): 951-960.   DOI: 10.13209/j.0479-8023.2019.063
Abstract1413)   HTML    PDF(pc) (1229KB)(273)       Save
Based on land use and land cover data, with the valuation systems developed by Xie, the ecosystem service values (ESV) of China (except Hong Kong, Macao and Taiwan Province) in 2000, 2010 and 2015 were analyzed, and their spatial and temporal distributions and variations were analyzed. The results show that ESV in China grew from 15917.1 billion yuan per year in 2000 to 16180.2 billion yuan per year in 2015. The ecosystem service value in China showed high level in the eastern provinces and low level in the western provinces. The spatial variations of ESV per capita were greater than those of ESV per unit area, but both of them decreased from 2000 to 2015, which were dominated by variations among regions. Provinces with increasing ESV concentrated in the west and the north of the country, while provinces with decreasing ESV concentrated in the east and the south.
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Bashang Forest Change Monitoring with Multi-Temporal MODIS Images and Random Forest Algorithm
ZHOU Jianing, ZHANG Jie, LI Tianhong
Acta Scientiarum Naturalium Universitatis Pekinensis    2018, 54 (4): 792-800.   DOI: 10.13209/j.0479-8023.2018.010
Abstract707)   HTML    PDF(pc) (8445KB)(134)       Save

In order to reveal the dynamic characteristics of the forest in Bashang area of Hebei Province, MODIS reflectivity and NDVI data with a spatial resolution of 250 m were used for forest classification, and a Thematic Mapper (TM) image in 2005 was resorted to aid training sample selection. With Random Forest Algorithm and time series of MODIS images, the forest in Bashang area was monitored from 2000 to 2015 in every two years. Compared with widely used classifiers such as maximum likelihood classifier and BP artificial neural network algorithm, Random Forest classifier showed the best performance with its overall accuracy and Kappa coefficient being 91.89% and 0.88 respectively. Binary coding was applied to the eight phases of forest distribution images, which can easily and rapidly reflect the changing trajectory from phase to phase. It showed that the severe forest changes mainly occurred in counties of Fengning, Weichang, Zhangbei and Guyuan during the years of 2000, 2010, and 2013.

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Analysis of Carbon Emissions and the Influence Factors in the Process of Urbanization among Chinese Provinces
ZHAO Donglin, LI Tianhong
Acta Scientiarum Naturalium Universitatis Pekinensis    2016, 52 (5): 947-958.   DOI: 10.13209/j.0479-8023.2016.060
Abstract1402)   HTML    PDF(pc) (2569KB)(1546)       Save

The article analyzes carbon emissions from industrial and living departments from 1995 to 2012, and urbanization rate is measured by three indicators, namely ratio of build-up area, ratio of non-agriculture population, and ratio of urban population. The results show that 1) the total amount of carbon emissions as well as the per capita carbon emissions is rising in 1995–2012, accordingly carbon emissions per unit of output present a decreasing trend. 2) In process of urbanization, Beijing, Shanghai and Tianjin have relatively lower carbon emissions and higher urbanization rates in urbanization stages. 3) The carbon emission of unit urbanization rate measured by three indicators show that most provinces present reduction trend till 2000 and then increase. Inner magnolia ranks the top in the carbon emission per urbanization rate 1. Hebei, Henan and Shandong rank the top in carbon emission per urbanization rate 2 and 3. 4) In the view of provinces, energy structure has limited impacts on carbon emissions, energy intensity has negative effect, and industrial structure has both positive and negative effect while economic level and population size have positive effect for all provinces. The results can provide scientific reference for the regional carbon emission reduction strategy.

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Assessing Water Quality of the Yellow River with Benthic Macro-invertebrate Indices
HUANG Xulei;LI Tianhong;JIANG Xiaohui
Acta Scientiarum Naturalium Universitatis Pekinensis    DOI: 10.13209/j.0479-8023.2015.070
Temporal and Spatial Variation of Ecological Risk Analysis in Yunnan Province Based on Land Use Spatial Structure
WANG Weiqi,LI Tianhong
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract652)      PDF(pc) (1028KB)(469)       Save
With the support of GIS and statistical analysis method, six landscape metrics reflecting the land use spatial structure were selected to build and calculate the ecological risk of Yunnan Province and its 16 prefectures using land use/cover maps of 100 m×100 m grid in 1980s, 1990, 2000 and 2005. The spatial and temporal variations of ecological risk was mapped and analyzed. Results showed that 1) The ecological risk of Yunnan Province was in the medium level with high risk in the northeast and southwest and low risk in the northwest and southeast from the view of spatial distribution; during the study periods, Diqing, Nujiang, Lijiang, Dali, Kunming, Yuxi, and Wenshan were all at a low risk level, while Lincang, Zhaotong and Qujing were in high risk areas. 2) The distribution of each prefecture’s ecological risk did not change obviously in 2005, compared with that in the 1980s. Most prefectures’ ecological risk level stayed the same level. 3) The ecological risk of each prefecture presented a trend of increasing in 1980s?1990 and 1990?2000. However, most prefectures experienced risk decrease in 2000?2005. 4) From 1980s to 2005, more than eighty percent of prefectures’ the ecological risk remained at their original level. The results can provide a scientific basis for ecological construction and regional ecological planning.
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Encode Landslide and Rock Fall Hazard and Interpretation with Monte Carlo Model in China
WANG Wei,LI Tianhong
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract629)      PDF(pc) (691KB)(300)       Save
The multi-scale encoding system for landslide and rock fall hazard and interpretation with Monte Carlo model is applied to hazard assessment in China. Counties and cities of China are encoded according to landslide and rock fall hazard information. Monte Carlo simulation is used to interpret some codes as reference, and the other codes are interpreted by matching them with reference. The whole China is zoned into five regions according to interpreted code hazard degrees that include very low, low, medium, high and very high. The correlation analysis shows that landslide and rock fall codes have high correlations with codes of geology factor and geomorphology factor. Verification of BP neural network, comparison between results interpreted by Monte Carlo model and historical disaster record and comparison between proposed approach and other approach indicate that results given by proposed approach are sufficient accuracy.
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A Multi-scale Encoding System for Landslide and Rock Fall Hazard and Interpretation with Monte Carlo Model
WANG Wei,LI Tianhong,NI Jinren
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract588)      PDF(pc) (544KB)(339)       Save
An encoding system for landslide and rock fall hazard, applicable to multi-scale, is proposed. Multi-factor information that can affect the landslide and rock fall hazard occurrences and their hazard degrees is given to study units by codes at different scales. Some study units with historical disaster records are selected as reference, and codes of these units in reference are interpreted by Monte Carlo model. Then a large number of other units can be interpreted according to the assumption that regions with similar codes should have similar hazards. Wide range applications, paying more attention to uncertainty study, low requirements for data, intuitive and detailed information presented by codes, avoiding redundancy of data and simplifying calculation are advantages of this approach. This study has great significance for identification of landslide and rock fall hazard characteristics and hazard assessment and prevention.
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Research Comment on Watershed Sediment Delivery Ratio
XIE Wangcheng,LI Tianhong
Acta Scientiarum Naturalium Universitatis Pekinensis   
A Preliminary Study on the Characteristics of β-Glucosidase from a Newly Isolated Aspergillus fumigates
LEI Jing,HUANG Wen,LI Tianhong
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract600)      PDF(pc) (1973KB)(417)       Save
A strain of Aspergillus fumigates with high activity towards Dioscorea zingiberensis saponins was isolated, and the characteristics of its β-glucosidase were studied preliminarily. As shown in the results, the β-glucosidase from Aspergillus fumigates which effectively produced diosgenin from saponins, exhibited the high level of activity and stablity at high temperature. At 65℃ and pH6.0, the β-Glucosidase activity of Aspergillus fumigates was 4.1 U/mg, and it retained 77% of its original activity for 48 hours with 1.5 mol/L ammonium sulfate. The β-Glucosidase of this Aspergillus fumigates hydrolyzed the D-glucose at the C-3position in trillin to yield saponin, and the transformation ratio was 56% within 24 hours.
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Ecological Risk Analysis for Shenzhen River Watershed Based on PESR Model
YANG Pei,LI Tianhong,MAO Xiaoling
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract516)            Save
In order to reveal the impact of rapid urbanization on watershed eco-environment, this paper establishes a pressure-effect-social response (PESR) model which is used to assess the regional ecological risk based on the pressure-state-response (PSR) framework model. The results show that, ERI of the watershed suffered some degree of reduction from 1993 to 2007, from level Ⅳ to level Ⅲ. PI increased continuously, and EI remained stable, while SRI decreased significantly with the strengthening of environmental protection measures. The assessment results show that despite the increasing pressure of society, the strengthening environmental protection measures could mitigate the risk dramatically.
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Regional Features of Non-point Source Pollution in Shiyan City
XU Wenjia,LI Tianhong,JIA Zhenbang,MAO Xiaoling
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract708)            Save
Based on former research and field survey data, the discharge, loss, composition and regional features of non-point source (NPS) pollution in Shiyan City were studied with the method of pollution discharge coefficient. The results show that pollutants of total nitrogen (TN) , total phosphorus (TP) flowing into water respectively were 17900 tons and 3800 tons for various NPS in 2004. Chemical fertilizer and animal waste were the primary source of TN, respectively, accounting for 39% and 25%. The main sources of TP came from soil erosion, fertilizer pollution and aquaculture, which made up more than 60% of TP. Among the districts (counties) of Shiyan City, Danjiangkou and Yunxi had the most serious NPS pollution, while the municipal district had the smallest. Different pollution types dominated in different districts or counties. Danjiangkou was featured by aquaculture pollution type; Yunxi, the type of fertilizer pollution; Zhushan and Yunxian, the type of fertilizer-soil pollution; and municipal district, Zhuxi and Fangxian were featured by comprehensive pollution type. Those results can be referenced by local government for making scientific NPS control strategies in Danj iangkou reservoir.
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Relationship between Urban Ecological Water Demand and Land Use Structure in Rapid Urbanization Area
YANG Pei,MAO Xiaoling,LI Tianhong
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract517)            Save
Land use changes seriously in the rapid urbanization area and could impact the urban ecosystem structure and function significantly, especially changing the characteristics of Urban Ecological Water Demand(UEWD). Based on the case study of Shenzhen, this paper analyzed the changes of SI (Index of Land use Structure Subject to UEWD) and EWI (Index of Urban Ecological Water Demand) in the period from 1988 to 2006. In order to know the relationship between UEWD and land-use change under different urbanization stages, the correlations between SI and EWI of inner and outside of the Shenzhen Special Economic Zone ( SSEZ) from 1993 to 2003 were discussed respectively. The results show that 1) EWI and SI were significantly decreased with different spatial character; 2) because of the different urbanization process of inner and outside of SSEZ, the characteristics of EWI and SI changes are distinct; 3) the relationship between EWI and SI is significantly positive correlated when the regional urbanization rate is low, but the correlation no longer exist as the rate increased further.
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Driving Mechanism of Human Forces to Urban Ecological Water Requirementsin Bao’an, Shenzhen
MAO Xiaoling,TIAN Kun,LI Jingping,LI Tianhong,LIU Yongwei
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract495)            Save
The interruption of human with the urban ecosystems will change the land use structure dramatically and result in deterioration of environmental quality as well as the remarkable change of ecological water requirements. Based on the case study of Bao’an, Shenzhen, this paper presents the quantitative relationship between urban ecological water requirements (UEWR) and the characteristic index for land use structure (SI). The driving mechanism of human activitiesto the land use change and UEWR is studied by Partial Least Squares Regression model. The estimation results indicate the significant negative correlation between UEWR and SI. The human driving forces can explain 50 % ~90 % of the deviation of the land use, especially more than 90 % of the urban construction area and SI. The explanation ability of the same driving forces to the ecological water requirements are 60 % ~80 %. The coefficients of the regression model represent the weight of the driving forces, among which the population is of the most important contribution. Through the same human driving mechanism, the UEWR can be explained and predicted by the simple index of SI.
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Characteristics of Urban Ecological Water Requirement in Bao’an, Shenzhen
MAO Xiaoling,TIAN Kun,LI Tianhong,XU Yi
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract628)            Save
Based on the case study of Bao’an, Shenzhen, this paper analyzes the characteristics of Urban Ecological Water Requirements( UEWR) during 1988-2004. The relationships among UEWR, water resources and land use are studied. The results are summarized as below: the amount of UEWR of Bao’an decreased remarkably from 2.12×108m3 in 1988 to 1.60×108m3 in 2004. The components of UEWR including forest, grassland and water ecosystems show the different trends. The significant positive correlation between UEWR and land use is found in this study. The ratio of UEWR in water resources structure is about 24%-33%. Water resources allocated to human society should be limited by 60%-70% in order to maintain the healthy ecosystemand urban sustainable development.
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Driving Mechanism of Human Forces to Urban Ecological Water Requirementsin Bao’an, Shenzhen
MAO Xiaoling,TIAN Kun,LI Jingping,LI Tianhong,LIU Yongwei
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract461)            Save
The interruption of human with the urban ecosystems will change the land use structure dramatically and result in deterioration of environmental quality as well as the remarkable change of ecological water requirements. Based on the case study of Bao’an, Shenzhen, this paper presents the quantitative relationship between urban ecological water requirements (UEWR) and the characteristic index for land use structure (SI). The driving mechanism of human activitiesto the land use change and UEWR is studied by Partial Least Squares Regression model. The estimation results indicate the significant negative correlation between UEWR and SI. The human driving forces can explain 50 % ~90 % of the deviation of the land use, especially more than 90 % of the urban construction area and SI. The explanation ability of the same driving forces to the ecological water requirements are 60 % ~80 %. The coefficients of the regression model represent the weight of the driving forces, among which the population is of the most important contribution. Through the same human driving mechanism, the UEWR can be explained and predicted by the simple index of SI.
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