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110篇 您的检索式:作者名="Ouyang Zhiyun"
    题名 作者 年代 出处 被引量
1Disturbance impacts of land use change on biodiversity conservation priority areas across China: 1990-2010显示文摘Land use change is one of the main drivers of biodiversity loss. In the last 20 years, China's land use pattern has undergone profound changes. This study constructs an Ecosystem Comprehensive Anthropogenic Disturbance Index(ECADI) to assess disturbance impacts of land use change between 1990 and 2010 on biodiversity conservation priority areas at national and regional scales. Four levels of biodiversity conservation areas were categorized: generally important areas, moderately important areas, important areas, and very important areas. The results indicated a higher ECADI value in 2010 in Central and Eastern China than in Western China, and the values of the moderately important, important and very important regions were lower than the average value of the whole country at all levels. Notably, in recent 20 years, the change extent of ECADI values in Central and Eastern China were much greater compared with that in Western China, and ECADI values in the moderately important, important and very important biodiversity conservation areas all showed increasing trends, with the increasing extent lower than that of whole China at all levels. Due to human activities such as urbanization in Eastern China and cropland reclamation in Northeast China and Xinjiang, ECADI values showed a medium increase trend(the change rate was about 1%–5% in 10 years), which indicated the need for more conservation efforts in those regions. However, ECADI values in the Loess Plateau presented a low decline trend(the change rate was about –1% to –0.1% in 10 years) after 2000 because of the obvious effectiveness of Green for Grain Project. Furthermore, the variation was negligible in the Tibetan Plateau.ZHAO Guosong LIU Jiyuan KUANG Wenhui OUYANG Zhiyun XIE Zhenglei 2015Journal of Geographical Sciences2015,25,5:26
2Ambient air quality trends and driving factor analysis in Beijing, 1983–2007显示文摘The rapid development in Beijing, the capital of China, has resulted in serious air pollution problems. Meanwhile great efforts have been made to improve the air quality, especially since 1998. The variation in air quality under the interaction of pollution and control in this mega city has attracted much attention. We analyzed the changes in ambient air quality in Beijing since the 1980's using the Daniel trend test based on data from long-term monitoring stations. The results showed that different pollutants displayed three trends: a decreasing trend, an increasing trend and a flat trend. SO2, dustfall, B[a]P, NO2 and PM10 fit decreasing trend pattern, while NOx showed an increasing trend, and CO, ozone pollution, total suspended particulate (TSP), as well as Pb fit the flat trend. The cause of the general air pollution in Beijing has changed from being predominantly related to coal burning to mixed traffic exhaust and coal burning related pollution. Seasonally, the pollution level is typically higher during the heating season from November to the following March. The interaction between pollution sources change and implementation of air pollution control measures was the main driving factor that caused the variation in air quality. Changes of industrial structure and improved energy effciency, the use of clean energy and preferred use of clean coal, reduction in pollution sources, and implementation of advanced environmental standards have all contributed to the reduction in air pollution, particularly since 1998.Ju Zhang Zhiyun Ouyang Hong Miao Xiaoke Wang 2011Journal of Environmental Sciences2011,23,12:22
3Modeling soil conservation, water conservation and their tradeoffs: A case study in Beijing显示文摘Natural ecosystems provide society with important goods and services. With the rapid increase in human populations and excessive utilization of natural resources, humans frequently enhance the production of some services at the expense of the others. Although the need for tradeoffs between conservation and development is urgent, the lack of efficient methods to assess such tradeoffs has impeded progress. Three land use strategy scenarios (development scenario, plan trend scenario and conservation scenario) were created to forecast potential changes in ecosystem services from 2007 to 2050 in Beijing, China. GIS-based techniques were used to map spatial and temporal distribution and changes in ecosystem services for each scenario. The provision of ecosystem services differed spatially, with significant changes being associated with different scenarios. Scenario analysis of water yield (as average annual yield) and soil retention (as retention rate per unit area) for the period 2007 to 2050 indicated that the highest values for these parameters were predicted for the forest habitat under all three scenarios. Annual yield/retention of forest, shrub, and grassland ranked the highest in the conservation scenario. Total water yield and soil retention increased in the conservation scenario and declined dramatically in the other two scenarios, especially the development scenario. The conservation scenario was the optimal land use strategy, resulting in the highest soil retention and water yield. Our study suggests that the evaluation and visualization of ecosystem services can effectively assist in understanding the tradeoffs between conservation and development. Results of this study have implications for planning and monitoring future management of natural capital and ecosystem services, which can be integrated into land use decision-making.Yang Bai Zhiyun Ouyang Hua Zheng Xiaoma Li Changwei Zhuang Bo Jiang 2012Journal of Environmental Sciences2012,24,3:21
4Response of runoff and soil loss to reforestation and rainfall type in red soil region of southern China显示文摘To evaluate the long-term effects of reforestation types on soil erosion on degraded land, vegetation and soil properties under conventional sloping farmland (CSF) and three different reforestation types including a Pinus massoniana secondary forest (PSF), an Eucommia ulmoides artificial economic forest (EEF) and a natural succession type forest (NST), were investigated at runoff plot scale over a six-year period in a red soil region of southern China. One hundred and thirty erosive rainfall events generating runoff in plots were grouped into four rainfall types by means of K-mean clustering method. Erosive rainfall type I is the dominant rainfall type. The amount of runoff and the soil loss under erosive rainfall type III were the most, followed by rain-fall type II, IV and I. Compared with CSF treatment, reforestation treatments decreased the average annual runoff depth and the soil loss by 25.5%-61.8% and 93.9%- 96.2% during the study period respectively. Meanwhile, runoff depth at PSF and EEF treatments was significantly lower than that in NST treatment, but no significant difference existed in soil erosion modulus among the three reforestation treatments. This is mainly due to the improved vegetation properties (i.e., vegetation coverage, biomass of above- and below-ground and litter-fall mass) and soil properties (i.e., bulk density, total porosity, infiltration rate and organic carbon content) in the three reforestation treatments compared to CSF treatment. The PSF and EEF are recommended as the preferred reforestation types to control runoff and soil erosion in the red soil region of southern China, with the NST potentially being used as an important supplement.Zhigang Huang Zhiyun Ouyang Fengrui Li Hua Zheng Xiaoke Wang 2010Journal of Environmental Sciences2010,22,11:18
5Ecological niche suitability model with an application in Taojiang land use planning显示文摘EcologicalnichesuitabilitymodelwithanapplicationinTaojianglanduseplanningOuyangZhiyun;WeismanJason;WangRusong(ResearchCenterf...Ouyang Zhiyun Weisman Jason Wang Rusong(Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China) Fu Guinan (Taojiang County Land Bureau, Hunan Province, China) 1994Journal of Environmental Sciences1994,6,4:17
6Effects of land use, climate, topography and soil properties on regional soil organic carbon and total nitrogen in the Upstream Watershed of Miyun Reservoir, North China显示文摘Soil organic carbon (SOC) and total nitrogen (TN) contents as well as their relationships with site characteristics are of profound importance in assessing current regional, continental and global soil C and N stocks and potentials for C sequestration and N conservation to offset anthropogenic emissions of greenhouse gases. This study investigated contents and distribution of SOC and TN under different land uses, and the quantitative relationships between SOC or TN and site characteristics in the Upstream Watershed of Miyun Reservoir, North China. Overall, both SOC and TN contents in natural secondary forests and grasslands were much higher than in plantations and croplands. Land use alone explained 37.2% and 38.4% of variations in SOC and TN contents, respectively. The optimal models for SOC and TN, achieved by multiple regression analysis combined with principal component analysis (PCA) to remove the multicollinearity among site variables, showed that elevation, slope, soil clay and water contents were the most significant factors controlling SOC and TN contents, jointly explaining 70.3% of SOC and 67.1% of TN contents variability. Only does additional 1.9% and 3% increase in the interpretations of SOC and TN contents variability respectively when land use was added to regressions, probably due to environment factors determine land use. Therefore, environmental variables were more important for SOC and TN variability than land use in the study area, and should be taken into consideration in properly evaluating effects of future land use changes on SOC and TN on a regional scale.Shufang Wang Xiaoke Wang Zhiyun Ouyang 2012Journal of Environmental Sciences2012,24,3:16
7Comparisons of carbon storages in Cunninghamia lanceolata and Michelia macclurei plantations during a 22-year period in southern China显示文摘Tree species composition was important for carbon storage within the same climate range.To quantify the dynamics of ecosystem carbon allocation as affected by different tree species,we measured the above-and below-ground biomass accumulation in 22 years,as well as the tissue carbon concentrations of trees in Cunninghamia lanceolata plantation and Michelia macclurei plantation.Results indicated that M.macclurei plantation significantly stored more carbon(174.8 tons/hm2) than C.lanceolata plantation(154.3 tons/hm2).Most of the carbon was found in the soil pool(57.1% in M.macclurei plantation,55.2% in C.lanceolata plantation).Tree and soil component of M.macclurei plantation possessed significantly higher carbon storage than that of C.lanceolata plantation(p < 0.05).No significant difference was found in the carbon storage of understory and forest floor.These results suggest that the broadleaved species(M.macclurei) possesses greater carbon sequestration potential than the coniferous species(C.lanceolata) in southern China.NIU Dong WANG Silong OUYANG Zhiyun 2009Journal of Environmental Sciences2009,21,6:15
8Impacts of climate variability and extremes on global net primary production in the first decade of the 21st century显示文摘许多研究估计了全球陆上的网的大小主要生产(NPP ) ,而是它的变化,空间地并且时间地,仍然保持不明确。由使用一个改进基于过程的陆上的生态系统模型( DLEM ,动态陆地生态系统模型),我们提供多重环境因素导致的全球陆上的 NPP 的估计并且在整个 第21 世纪的第一十年在生物群系和全球层次并且沿着纬度检验陆上的 NPP 的反应到气候可变性。模型模拟在 20002009 期间估计 54.6 Pg C 年 1 的平均全球陆上的 NPP,从 2002 ~ 56.4 Pg C 的干燥的年里的 52.8 Pg C 年 1 变化 2008 的湿年里的年 1 。在湿年里,与十的平均数相比的陆上的 NPP 的大增加在 Amazonia,非洲和澳大利亚是流行的。在干燥的年里,然而,我们与十的平均数相比在全球陆上的 NPP 发现了 3.2% 减小,首先由于在热带区域的有限潮湿供应。在全球水平,降水在陆上的 NPP 解释了约 63% 变化,当剩余的在温度和另外的环境因素被归因于变化时。降水是在低纬度的区域在陆上的 NPP 决定内部年度的变化的主要因素。在中间纬度、高纬度的区域,然而,温度可变性大部分控制了陆上的 NPP 的大小。我们的结果暗示温暖并且增加气候极端事件的那投射气候将改变大小和全球陆上的 NPP 的空间与时间的模式。PAN Shufen TIAN Hanqin DANGAL Shree R.S. OUYANG Zhiyun LU Chaoqun YANG Jia TAO Bo REN Wei BANGER Kamaljit YANG Qichun ZHANG Bowen 2015Journal of Geographical Sciences2015,25,9:15
9Changes in Ecosystem Service of Soil Conservation Between 2000 and 2010 and Its Driving Factors in Southwestern China显示文摘Human activities significantly alter ecosystems and their services; however, quantifying the impact of human activities on ecosystems has been a great challenge in ecosystem management. We used the Universal Soil Loss Equation and county-level socioeconomic data to assess the changes in the ecosystem service of soil conservation between 2000 and 2010, and to analyze its spatial characteristics and driving factors in the southwestern China. The results showed that cropland in the southwestern China decreased by 3.74%, while urban land, forest, and grassland areas increased by 46.78%, 0.86%, and 1.12%, respectively. The soil conservation increased by 1.88 × 10^(11) kg, with deterioration only in some local areas. The improved and the degraded areas accounted for 6.41% and 2.44% of the total land area, respectively. Implementation of the Sloping Land Conversion Program and urbanization explained 57.80% and 23.90% of the variation in the soil conservation change, respectively, and were found to be the main factors enhancing soil conservation. The 2008 Wenchuan earthquake was one of the factors that led to the degradation of soil conservation. Furthermore, industrial adjustment, by increasing shares of Industry and Service and reducing those of Agriculture, has also promoted soil conservation. Our results quantitatively showed and emphasized the contributions to soil conservation improvement made by implementing ecological restoration programs and promoting urbanization. Consequently, these results provide basic information to improve our understanding of the effects of ecological restoration programs, and help guide future sustainable urban development and regional industrial restructuring.RAO Enming XIAO Yi OUYANG Zhiyun ZHENG Hua 2016Chinese Geographical Science2016,26,2:15
10Evaluating Beijing’s human carrying capacity from the perspective of water resource constraints显示文摘As the demands on limited water resources intensify, concerns are being raised about the human carrying capacity of these resources. However, few researchers have studied the carrying capacity of regional water resources. Beijing, the second-largest city in China, faces a critical water shortage that will limit the city’s future development. We developed a method to quantify the carrying capacity of Beijing’s water resources by considering water-use structures based on the proportions of water used for agricultural, industrial, and domestic purposes. We defined a reference structure as 45:22:33 (% of total, respectively), an optimized structure as 40:20:40, and an ideal structure as 50:15:35. We also considered four domestic water quotas: 55, 75, 95, and 115 m 3 /(person·yr). The urban carrying capacity of 10–12 million was closest to Beijing’s actual 2003 population for all three water-use structures with urban domestic water use of 75 m 3 /(person·yr). However, after accounting for our underlying assumptions, the adjusted carrying capacity is closer to 5–6 million. Thus, Beijing’s population in 2003 was almost twice the adjusted carrying capacity. Based on this result, we discussed the ecological and environmental problems created by Beijing’s excessive population and propose measures to mitigate these problems.Yingxuan Zhang Min Chen Wenhua Zhou Changwei Zhuang Zhiyun Ouyang 2010Journal of Environmental Sciences2010,22,8:14
11Preliminary report on methane emissions from the Three Gorges Reservoir in the summer drainage period显示文摘Recently reported summertime methane (CH4) emissions (6.7 ± 13.3 mg CH4/(m2·hr)) from newly created marshes in the drawdown area of the Three Gorges Reservoir (TGR), China have triggered broad concern in academic circles and among the public. The CH4 emissions from TGR water surfaces and drawdown areas were monitored from 3rd June to 16th October 2010 with floating and static chambers and gas chromatography. The average CH4 emission flux from permanently flooded areas in Zigui, Wushan and Yunyang Counties was (0.33 ± 0.09) mg CH4/(m2·hr). In half of these hottest months of the year, the wilderness, cropland and deforested drawdown sites were aerobic and located above water level, and the CH4 emissions were very small, ranging from a sink at 0.12 mg CH4/(m2·hr) to a source at 0.08 mg CH4/(m2·hr) except for one mud-covered site after flood. Mean CH4 emission in flooded drawdown sites was 0.34 mg CH4/(m2·hr). The emissions from the rice paddy sites in the drawdown area were averaged at (4.86 ± 2.31) mg CH4/(m2·hr). Excepting the rice-paddy sites, these results show much lower emission levels than previously reported. Our results indicated considerable spatial and temporal variation in CH4 emissions from the TGR. Human activities and occasional events, such as flood, may also affect emission levels. Long-term CH4 measurements and modeling in a large region are necessary to accurately estimate greenhouse gas emissions from the TGR.Fei Lu Le Yang Xiaoke Wang Xiaonan Duan Yujing Mu Wenzhi Song Feixiang Zheng Junfeng Niu Lei Tong Hua Zheng Yongjuan Zhou Jiangxiao Qiu Zhiyun Ouyang 2011Journal of Environmental Sciences2011,23,12:13
12Evaluating Conservation Effectiveness of Nature Reserves Established for Surrogate Species:Case of a Giant Panda Nature Reserve in Qinling Mountains,China显示文摘Many nature reserves are established to protect the habitat needs of particular endangered species of interest but their effectiveness for protecting other species is questionable.In this study,this effectiveness was evaluated in a nature reserve network located in the Qinling Mountains,Shaanxi Province,China.The network of reserves was established mainly for the conservation of the giant panda,a species considered as a surrogate for the conservation of many other endangered species in the region.The habitat suitability of nine protected species,including the giant panda,was modeled by using Maximum Entropy(MAXENT)and their spatial congruence was analyzed.Habitat suitability of these species was also overlapped with nature reserve boundaries and their management zones(i.e.,core,buffer and experimental zones).Results show that in general the habitat of the giant panda constitutes a reasonable surrogate of the habitat of other protected species,and giant panda reserves protect a relatively high proportion of the habitat of other protected species.Therefore,giant panda habitat conservation also allows the conservation of the habitat of other protected species in the region.However,a large area of suitable habitat was excluded from the nature reserve network.In addition,four species exhibited a low proportion of highly suitable habitat inside the core zones of nature reserves.It suggests that a high proportion of suitable habitat of protected species not targeted for conservation is located in the experimental and buffer zones,thus,is being affected by human activities.To increase their conservation effectiveness,nature reserves and their management zones need to be re-examined in order to include suitable habitat of more endangered species.The procedures described in this study can be easily implemented for the conservation of many endangered species not only in China but in many other parts of the world.XU Weihua Andrés VIA QI Zengxiang OUYANG Zhiyun LIU Jianguo LIU Wei WAN Hui 2014Chinese Geographical Science2014,24,1:12
13Soil microbial community structure and function responses to successive planting of Eucalyptus显示文摘Many studies have shown soil degradation after the conversion of native forests to exotic Eucalyptus plantations. However, few studies have investigated the long-term impacts of short-rotation forestry practices on soil microorganisms. The impacts of Eucalyptus successive rotations on soil microbial communities were evaluated by comparing phospholipid fatty acid(PLFA) abundances,compositions, and enzyme activities of native Pinus massoniana plantations and adjacent 1st, 2nd, 3rd, 4th generation Eucalyptus plantations. The conversion from P. massoniana to Eucalyptus plantations significantly decreased soil microbial community size and enzyme activities, and increased microbial physiological stress. However, the PLFA abundances formed '∪' shaped quadratic functions with Eucalyptus plantation age. Alternatively, physiological stress biomarkers, the ratios of monounsaturated to saturated fatty acid and Gram+ to Gram- bacteria, formed '∩' shaped quadratic functions, and the ratio of cy17:0 to 16:1ω7c decreased with plantation age. The activities of phenol oxidase, peroxidase, and acid phosphatase increased with Eucalyptus plantation age, while the cellobiohydrolase activity formed '∪' shaped quadratic functions. Soil N:P, alkaline hydrolytic nitrogen, soil organic carbon, and understory cover largely explained the variation in PLFA profiles while soil N:P, alkaline hydrolytic nitrogen, and understory cover explained most of the variability in enzyme activity. In conclusion, soil microbial structure and function under Eucalyptus plantations were strongly impacted by plantation age. Most of the changes could be explained by altered soil resource availability and understory cover associated with successive planting of Eucalyptus. Our results highlight the importance of plantation age for assessing the impacts of plantation conversion as well as the importance of reducing disturbance for plantation management.Falin Chen Hua Zheng Kai Zhang Zhiyun Ouyang Huailin Li Bing Wu Qian Shi 2013Journal of Environmental Sciences2013,25,10:12
14Spatio-temporal Variation of Wind Erosion in Inner Mongolia of China Between 2001 and 2010显示文摘Using Geographic Information System(GIS), based on wind speed, precipitation, topographic, soil, vegetation coverage and land use data of Inner Mongolia between 2001 and 2010, we applied the revised wind erosion equation(RWEQ) model to simulate wind erosion intensity. The results showed that an area of approximately 47.8 × 10~4 km^2 experienced wind erosion in 2010, 23.2% of this erosion could be rated as severe, and 46.0% as moderate. Both the area and the intensity of wind erosion had decreased from 2001 to 2010, the wind erosion area reduced 10.1%, and wind erosion intensity decreased by 29.4%. Precipitation, wind speed, population size and urbanization in rural areas, and gross domestic product of primary industry(GDP1) were the main factors influencing wind erosion. Overall, these factors accounted for 88.8% of the wind erosion. These results indicated that the decrease in wind erosion over the past decade related to the increase in precipitation and the decrease in the number of windy days, while modest urban development and optimization of the economic structure might partially reduced the level of ecological pressure, highlighting the importance of human activities in controlling wind erosion.JIANG Ling XIAO Yi ZHENG Hua OUYANG Zhiyun 2016Chinese Geographical Science2016,26,2:11
15Optimizing Hotspot Areas for Ecological Planning and Management Based on Biodiversity and Ecosystem Services显示文摘The significance of biodiversity and ecosystem services are gradually recognized by human as an approach towards sustainability, so it is important to understand relationships and congruence between them to support conservation planning, especially in the hotspot areas with a prominent role in conservation. However, the management of most conservation hotspots mainly focused on biodiversity, and rarely concerned with ecosystem services. With the aim of proposing criteria for conservation strategies that contribute to the optimization of biodiversity and ecosystem services, in this study, a Geographic Information System(GIS)-based approach was designed to estimate and map the biodiversity and ecosystem services in Chongqing Municipality of China. Furthermore, the distributions of hotspot areas for biodiversity and ecosystem services were mapped based on the relationship between cumulative ecosystem services and areas. Finally the statistical analysis was processed focused on specific conservation objectives. The results showed that hotspot areas can conserve the most biodiversity but with the least ecosystem services under the conservation plans target to biodiversity conservation. In contrast, depending on the ecosystem services of interest, hotspot areas can conserve the largest ecosystem services but with the least biodiversity. By integrating biodiversity and ecosystem services into conservation plan, we found that the conservation and regeneration of these small areas, would contribute to a conservation of 44% of the biodiversity hotspot and 14%–42% of the ecosystem services hotspot. Moreover, the current nature reserve selection was not maximize the biodiversity and ecosystem services compared to integration strategy, indicating that hotspot areas conservation and selection is vital for optimization protection of biodiversity and ecosystem services, and has practical significance for natural resources and ecosystem management.XIAO Yang OUYANG Zhiyun XU Weihua XIAO Yi ZHENG Hua XIAN Chaofan 2016Chinese Geographical Science2016,26,2:11
16Driving Forces and Their Effects on Water Conservation Services in Forest Ecosystems in China显示文摘Identifying the driving forces that cause changes in forest ecosystem services related to water conservation is essential for the design of interventions that could enhance positive impacts as well as minimizing negative impacts. In this study, we propose an assessment concept framework model for indirect-direct-ecosystem service(IN-DI-ESS) driving forces within this context and method for index construction that considers the selection of a robust and parsimonious variable set. Factor analysis was integrated into two-stage data envelopment analysis(TS-DEA) to determine the driving forces and their effects on water conservation services in forest ecosystems at the provincial scale in China. The results showed the following. 1) Ten indicators with factor scores more than 0.8 were selected as the minimum data set. Four indicators comprising population density, per capita gross domestic product, irrigation efficiency, and per capita food consumption were the indirect driving factors, and six indicators comprising precipitation, farmland into forestry or pasture, forest cover, habitat area, water footprint, and wood extraction were the direct driving forces. 2) Spearman's rank correlation test was performed to compare the overall effectiveness in two periods: stage 1 and stage 2. The calculated coefficients were 0.245, 0.136, and 0.579, respectively, whereas the tabulated value was 0.562. This indicates that the driving forces obviously differed in terms of their contribution to the overall effectiveness and they caused changes in water conservation services in different stages. In terms of the variations in different driving force effects in the years 2000 and 2010, the overall, stage 1, and stage 2 variances were 0.020, 0.065, and 0.079 in 2000, respectively, and 0.018, 0.063, and 0.071 in 2010. This also indicates that heterogeneous driving force effects were obvious in the process during the same period. Identifying the driving forces that affect service changes and evaluating their efficiency have significant policy implications for the management of forest ecosystem services. Advanced effectiveness measures for weak regions could be improved in an appropriate manner. In this study, we showed that factor analysis coupled with TS-DEA based on the IN-DI-ESS framework can increase the parsimony of driving force indicators, as well as interpreting the interactions among indirect and direct driving forces with forest ecosystem water conservation services, and reducing the uncertainty related to the internal consistency during data selection.GONG Shihan XIAO Yang XIAO Yi ZHANG Lu OUYANG Zhiyun 2017Chinese Geographical Science2017,27,2:9
17Spatial and Temporal Changes of Arable Land Driven by Urbanization and Ecological Restoration in China显示文摘Since the industrial revolution, human activities have both expanded and intensified across the globe resulting in accelerated land use change. Land use change driven by China’s development has put pressure on the limited arable land resources, which has affected grain production. Competing land use interests are a potential threat to food security in China. Therefore, studying arable land use changes is critical for ensuring future food security and maintaining the sustainable development of arable land. Based on data from several major sources, we analyzed the spatio-temporal differences of arable land among different agricultural regions in China from 2000 to 2010 and identified the drivers of arable land expansion and loss. The results revealed that arable land decreased by 5.92 million ha or 3.31%. Arable land increased in the north and decreased in the south of China. Urbanization and ecological restoration programs were the main drivers of arable land loss, while the reclamation of other land cover types(e.g., forest, grassland, and wetland) was the primary source of the increased arable land. The majority of arable land expansion occurred in the Northwest, but the centroid for grain production moved to northeast, which indicated that new arable land was of poor quality and did not significantly contribute to the grain production capacity. When combined with the current ‘Red Line of Arable Land Policy’(RAL) and ‘Ecological Redline Policy’(EPR), this study can provide effective information for arable land policymaking and help guide the sustainable development of arable land.WANG Liyan ANNA Herzberger ZHANG Liyun XIAO Yi WANG Yaqing XIAO Yang LIU Jianguo OUYANG Zhiyun 2019Chinese Geographical Science2019,29,5:9
18Spatial-temporal Patterns and Driving Forces of Water Retention Service in China显示文摘Overwhelming water-deficiency conditions and an unbalanced water supply and demand have been major concerns of both the Chinese government and the general public during recent decades. Studying the spatial-temporal patterns and impact factors that influence water retention in China is important to enhance the management of water resources in China and other similar countries. We employed a revised Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST) model and regression analyses to investigate the water retention service in China. The results showed that the southeastern China generally performed much better than Northwest China in terms of the spatial distribution of water retention. In general, the efficacy of the water retention service in China increased from 2000 to 2014; although some areas still had a downward trend. Water retention service increased significantly(P < 0.05) in aggregate in the Qinghai-Tibet Plateau, and the Da Hinggan Mountains and Xiao Hinggan Mountains. However, the service in southwestern China showed a decreasing trend(P < 0.05), which would have significant negative impact on the downstream population. This study also showed that in China the changes in water retention service were primarily due to climate change(which could explain 83.49% of the total variance), with anthropogenic impact as a secondary influence(likewise the ecological programs and socioeconomic development could explain 9.47% and 1.06%, respectively). Moreover, the identification of water retention importance indicated that important areas conservation and selection based on downstream beneficiaries is vital for optimization protection of ecosystem services, and has practical significance for natural resources and ecosystem management.XIAO Yang OUYANG Zhiyun 2019Chinese Geographical Science2019,29,1:9
19Effects of spatial resolution of remotely sensed data on estimating urban impervious surfaces显示文摘Impervious surfaces are the result of urbanization that can be explicitly quantified,managed and controlled at each stage of land development.It is a very useful environmental indicator that can be used to measure the impacts of urbanization on surface runoff,water quality,air quality,biodiversity and microclimate.Therefore,accurate estimation of impervious surfaces is critical for urban environmental monitoring,land management,decision-making and urban planning.Many approaches have been developed to estimate surface imperviousness,using remotely sensed data with various spatial resolutions.However,few studies,have investigated the effects of spatial resolution on estimating surface imperviousness.We compare medium-resolution Landsat data with high-resolution SPOT images to quantify the imperviousness in Beijing,China.The results indicated that the overall 91% accuracy of estimates of imperviousness based on TM data was considerably higher than the 81% accuracy of the SPOT data.The higher resolution SPOT data did not always predict the imperviousness of the land better than the TM data.At the whole city level,the TM data better predicts the percentage cover of impervious surfaces.At the sub-city level,however,the ring belts from the central core to the urban-rural peripheral,the SPOT data may better predict the imperviousness.These results highlighted the need to combine multiple resolution data to quantify the percentage of imperviousness,as higher resolution data do not necessarily lead to more accurate estimates.The methodology and results in this study can be utilized to identify the most suitable remote sensing data to quickly and efficiently extract the pattern of the impervious land,which could provide the base for further study on many related urban environmental problems.Weifeng Li Zhiyun Ouyang Weiqi Zhou Qiuwen Chen 2011Journal of Environmental Sciences2011,23,8:8
20Soil temperature and moisture sensitivities of soil CO_2 efflux before and after tillage in a wheat field of Loess Plateau,China显示文摘As a conventional farming practice,tillage has lasted for thousands of years in Loess Plateau,China.Although recent studies show that tillage is a prominent culprit to soil carbon loss in croplands,few studies have investigated the influences of tillage on the responses of soil CO2 efflux(SCE) to soil temperature and moisture.Using a multi-channel automated CO2 efflux chamber system,we measured SCE in situ continuously before and after the conventional tillage in a rain fed wheat field of Loess Plateau,China.The changes in soil temperature and moisture sensitivities of SCE,denoted by the Q10 value and linear regression slope respectively,were compared in the same range of soil temperature and moisture before and after the tillage.The results showed that,after the tillage,SCE increased by 1.2-2.2 times;the soil temperature sensitivity increased by 36.1%-37.5%;and the soil moisture sensitivity increased by 140%-166%.Thus,the tillage-induced increase in SCE might partially be attributed to the increases in temperature and moisture sensitivity of SCE.Hongxing Zhang Xiaoke Wang Zongwei Feng Junzhu Pang Fei Lu Zhiyun Ouyang Hua Zheng Wenzhao Liu Dafeng Hui 2011Journal of Environmental Sciences2011,23,1:7
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