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Spatial Distribution Pattern and Application of Fourth-Generation Mature Larvae of Cotton Bollworm(Helicoverpa armigera Hübner) in Corn Field
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作者 李贺年 齐巧丽 +1 位作者 李德新 姚克荣 《Plant Diseases and Pests》 CAS 2011年第2期36-38,共3页
[ Objective] The paper was to study the spatial distribution pattern of fourth-generation mature larvae of cotton bellworm in corn field. [ Method] The plots with different occurrence densities of fourth-generation co... [ Objective] The paper was to study the spatial distribution pattern of fourth-generation mature larvae of cotton bellworm in corn field. [ Method] The plots with different occurrence densities of fourth-generation cotton bollworm were investigated from August to September in 2009. Six groups of sampling data were obtained, and seven indicators including aggregation index method, Iwao method and Taylor method, etc. were used to determine its spatial distribution pattern. [ Result ] Aggregation index test showed that in all plots, Moore I 〈 0, Lloyed m*/m 〈 1, Kuno Ca 〈 0, diffusion coefficient C 〈 1, diffusion index 16 〈 1, negative binomial distribution K 〈 0, indicating that mature larvae of cotton bollworm showed uniform distribution in summer corn. Iwae regression equation of fourth-genera- tion mature larvae of cotton boUworm in summer corn was m * = 0. 090 6 + 0. 766 9 m, r = 0. 986 3, indicating that the basic components of cotton bollworm distribu- ted was single individual, and mature larvae of cotton bollworm in summer corn showed uniform distribution. The optimal sampling number of fourth-generation ma- ture larvae of cotton bollworm in corn under different population densities could be calculated using formula N1 = ( 1. 090 6/m -0. 233 1 )/D2. [ Conclusion] The result provided basis for accurate evaluation of population quantities and variation law of cotton boUworm, as well as prediction and control of the pest. 展开更多
关键词 MAIZE Cotton bollworm spatial distribution pattern Sampling technique
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Preliminary Study on Spatial Distribution Pattern of Endoclyta signifer Walker Larva
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作者 曹书阁 庞正轰 +2 位作者 杨秀好 于永辉 丘润清 《Plant Diseases and Pests》 CAS 2011年第2期28-31,72,共5页
[ Objective ] The paper was to study the spatial distribution of Endoclyta signifer Walker Larva. [ Method] The larvae distribution in eucalyptus planta- tion in Beiliu and Luchuan counties of Guangxi province were in... [ Objective ] The paper was to study the spatial distribution of Endoclyta signifer Walker Larva. [ Method] The larvae distribution in eucalyptus planta- tion in Beiliu and Luchuan counties of Guangxi province were investigated. Ten standard plots were set, and the spatial distribution pattern of E. signifer larva was confirmed using six different aggregation indexes and regression model analysis method. [ Result] The larvae mainly distributed in the base of tnmk lower than 1 m, and its spatial distribution pattern was mainly aggregated distribution, which was caused by the enviromnental factors. The optimum sampling formula of E. signifer larva under different population densities was n = t2 ( 1.1/m + 0. 674 4)/D2, and limited sequential sampling decision model was T'0(n), T'0(n) = n + 1. 332√n( m0 = 1 ). [ Conclusion] The result provided scientific basis for sampling and forecasting of E. signifier. 展开更多
关键词 Endoclyta signifer Walker spatial distribution pattern Aggregation indexes Regression model
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Spatial Distribution Pattern of Overwintering Larvae of Dendrlimus punctatus
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作者 刘有莲 《Plant Diseases and Pests》 CAS 2010年第4期32-35,共4页
Based on the data of mean population density of overwintering larvae of Dendrolimus punctatus in Shatang forest farm in Guangxi Province, the spatial pattern of overwintering larva of D. punctatus were analyzed by the... Based on the data of mean population density of overwintering larvae of Dendrolimus punctatus in Shatang forest farm in Guangxi Province, the spatial pattern of overwintering larva of D. punctatus were analyzed by the distribution index and regression model method. The results showed that the spatial pattern of overwintering larvae of D. punctatus assumed the aggregation pattern, the basic component of distribution was individual group. The optimal sampling number of forest survey and the sequential sampling analysis were presented, and the upper and low bound index for controlling D. punctatus were put forward to provide certain theoretical basis for integrated pest management. 展开更多
关键词 Dendrolimus punctatus Walker. spatial distribution pattern Sequential sampling Guangxi Shatang forest farm
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On Spatial Distribution Pattern of Broccoli Clubroot Disease and and the Sampling Technique
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作者 钟列权 王会福 余山红 《Agricultural Science & Technology》 CAS 2015年第12期2715-2719,共5页
[Objective] To further improve the prediction and forecast and continuous control ability of broccoli clubroot disease. [Methods] The spatial distribution pattern of diseased or infected plants was analyzed using the ... [Objective] To further improve the prediction and forecast and continuous control ability of broccoli clubroot disease. [Methods] The spatial distribution pattern of diseased or infected plants was analyzed using the least square method, fre- quency distribution, aggregation index, m*-m regression analysis and Taylor's pow- er law model. [Result] The field distribution of broccoli plants with clubroot disease tended to be aggregated distribution, m'-m regression analysis showed that the el- ementary composition of the spatial distribution of diseased or infected plants was individual colony, the individuals attracted each other; the disease had obvious dis- ease focus in the field, and the individual colony showed uniform distribution pattern in the field. Taylor's power law showed that the spatial pattern of individual dis- eased or infected plant with clubroot disease tended to be uniform distribution with the increase of the density. On the basis of this, Iwao optimal theoretical sampling model and sequential sampling model were established, namely N =273.954 1/m- 59.698 5, To (N)=0.368 4N±1.926 8√N, respectively, it meant that when surveying N plants, if the accumulative incidence rate exceeded upper bound, the field can be set as control object; if the accumulative incidence rate didn't reach lower bound, it can be set as uncontrol field; if the accumulative incidence rate was between upper bound and lower bound, it should be surveyed continuously until the maximum sample size (mo=0.368 4) appeared, that was, the disease incidence was 15%, so the sampling number should be 684 plants. [Conclusion] The research results had very important instructive meaning for disease control. 展开更多
关键词 Broccoli clubfoot disease spatial distribution pattern The optimal theo- retical sampling model Sequential sampling model Sampling number
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Spatial Distribution Pattern and Han Subgroup Characteristics of Traditional Villages in Guangdong 被引量:2
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作者 YUAN Shaoxiong YIN Xiaoling +2 位作者 XIONG Haixian SUN Zhongyu HUANG Guangqing 《Journal of Landscape Research》 2018年第1期25-32,共8页
A total of 126 traditional villages in Guangdong were selected for research to analyze their spatial distribution pattern, spatial autocorrelation, and Han subgroup characteristics through the spatial analysis with GI... A total of 126 traditional villages in Guangdong were selected for research to analyze their spatial distribution pattern, spatial autocorrelation, and Han subgroup characteristics through the spatial analysis with GIS. The results showed that the traditional villages in Guangdong were distributed compactly, which was similar to that in other provinces; on the prefecture-level city scale, they were mainly distributed in Meizhou, Qingyuan, Zhanjiang, and Zhaoqing, showing a central distribution; on the regional scale, they were mainly distributed in northern Guangdong and the Pearl River Delta, indicating an unbalanced distribution; their density of spatial distribution showed a significant difference with a provincial distribution density of 0.59 per thousand km^2 and the highest distribution density of 2.14 per thousand km^2; there were four gathering areas accommodating many traditional villages, namely Meizhou-Chaoshan area, Guangfo-Dongguan area, Leizhou in Zhanjiang, and Lianzhou in Qingyuan; the spatial distribution of traditional villages, which presented a pattern of hot spot—sub-hot spot—sub-cold spot—cold spot, had a significant global spatial autocorrelation, and areas in similar sizes were tending towards gathering; traditional villages in Guangdong belonged to the Cantonese-speaking group and Hakka-speaking group with a density of 0.59 per thousand km^2 and 0.48 per thousand km^2 respectively, and Han subgroup with the highest distribution density was the minority areas of 1.31 per thousand km^2, followed by Shaozhou dialect area with a density of 1.00 per thousand km^2. 展开更多
关键词 Traditional villages spatial distribution pattern spatial autocorrelation Han subgroup distribution GUANGDONG
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Spatial Distribution Patterns of Cultural Facilities in Shenzhen Based on GIS and Big Data 被引量:2
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作者 QU Huan 《Journal of Landscape Research》 2018年第4期48-54,共7页
As the city’s soft powef,culture is the basic core of urban competitiveness. The spatial concentration of cultufal facilities can show the development status of the dtfs cultural functions in the spatial ky... As the city’s soft powef,culture is the basic core of urban competitiveness. The spatial concentration of cultufal facilities can show the development status of the dtfs cultural functions in the spatial kyout. In this paper,POI data of Baidu Maps were used to conduct kernel density analysis and comprehensive evaluation of the spatial distribution of cultural facilities in Shenzhen; mean center point method was used to measure the degree of deviation between Shenzhen population centers and cultural facilities centers; the nearest distance method was used to measure the spatial distribution of cultural facilities space and the accessibility to geometdc centers of streets. The results showed that among the four types of cultural facilities in Shenzhen, librades were the most concentrated, accounting for 63% of the total number of cultural facilities, followed by cultxite and arts centers, museiims, and galleries; tiiere was a great disparity in the number of cultural facilities in various districts and subdistricts in Shenzhen, with a clear agglomeration effect in space; from the district level, cultural faculties spatially distributed from the southwest to the northeast by three gradients; from the street leviel, cultural facilities showed the distribution pattern of ^decreasing from west to eastf and a high d^tee of recognition for convenient transportation; the cultural facilities inside the Shenzhen Special Economic Zone (except Yantdan District) were more reasonable in spatial distribution, and the number of people served was more than that of cultural Realities outside the Shenzhen Special Economic Zone, while residents outside the Shenzhen Special Economic Zone enjoyed significantly more cultutal facilities than that inside the Shenzhen Special Economic Zone; the goal of the e£10-min cultutal dtdeJ, in Shenzhen had been initially completed, that is, residents could reach 72.41% of the streets with cultural facilities within a 10-min /raJk, but thefe were still 50% districts and 5.1% streets that wefe equipped with, unreasonably distributed cultufal facilities or few cultufal facilities. 展开更多
关键词 SHENZHEN Cultural facilities spatial distribution pattern ACCESSIBILITY
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Spatial Distribution Pattern and Sampling Technology of Soritia leptalina Larvae on Quercus aquifolioides 被引量:2
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作者 TANG Xiaoqin LU Jie ZANG Jiancheng 《Journal of Landscape Research》 2017年第2期38-41,46,共5页
Soritia leptalina endangers mainly Quercus aquifolioides, and it became particularly rampant on Q. aquifolioides in Linzhi area, Tibet. By applying field investigation and lab analysis, this study explored the spatial... Soritia leptalina endangers mainly Quercus aquifolioides, and it became particularly rampant on Q. aquifolioides in Linzhi area, Tibet. By applying field investigation and lab analysis, this study explored the spatial distribution type and sampling technology of S. leptalina larvae on Q. aquifolioides. The results showed that insect density in the upper layer of tree canopy is higher than that in the middle and lower layer,that in the upper, middle and lower layer of different levels varies greatly, and insect density in different directions follows the sequence: east > north > west > south; spatial distribution of S. leptalina on Q.aquifolioides belongs to aggregation type, larvae show mutual repulsion; aggregation of S. leptalina is the result of biological characteristics of its larvae and the habitat environment; taking Iwa regression model as the basis, the optimal sampling quantity is determined. The study disclosed the spatial distribution rules of S.leptalina on Q. aquifolioides, and on the basis of which could provide the theoretical basis for preventing Q.aquifolioides from the damage of S. leptalina, and also scientific support for studying the spatial distribution pattern of this insect and its natural enemies on other hosts. 展开更多
关键词 Soritia leptalina Quercus aquifolioides spatial distribution pattern Sampling technology
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Space-time Dynamics of Dendroctonus valens Population in China and Spatial Sampling Technique based on Its Spatial Distribution Pattern
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作者 Pan Jie Wang Tao +2 位作者 Zong Shixiang Wen Junbao Luo Youqing 《Plant Diseases and Pests》 CAS 2015年第3期20-24,38,共6页
Red turpentine beetle (RTB), Dendroctongs valens LeConte, is a destructive forest invasive species in China, it mainly attacks Pings tabuliformis and P. bungeana. So far it has spread rapidly to the provinces of Sha... Red turpentine beetle (RTB), Dendroctongs valens LeConte, is a destructive forest invasive species in China, it mainly attacks Pings tabuliformis and P. bungeana. So far it has spread rapidly to the provinces of Shanxi, Hebei, Henan, Shanxi and Beijing since its first outbreak in Shanxi Province in 1998, and has caused extensive tree mortality. Space-time dynamics of D. valens population and spatial sampling technique based on its spatial distribution pattern were ana- lyzed using geostatistical methods in the pure P. tabuliforis forests and mixedwood stands which were at different damage levels. According to the spatial distribu- tion of D. valeas population, the specific spatial sampling technique was also studied, and then was compared with traditional sampling technique. The spatial sam- piing technique combined with sampling theory and the biological characteristics of D. valens population, which not only could calcnlate the error of the sampling, but also could discuss the optimal sampling number and the optimum size of plot according to different damage levels and different stand types. This helps to explain population expansion and colonization mechanism of D. valens, and to provide a good reference for adopting snitable control measures. 展开更多
关键词 Dendroctonus valens spatial distribution pattern GEOSTATISTICS Space-time dynamics spatial sampling
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Temporal and Spatial Distribution Patterns of Grain Crops in the West Liaohe River Basin 被引量:3
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作者 封志明 杨玲 杨艳昭 《Journal of Resources and Ecology》 CSCD 2014年第3期244-252,共9页
Here,we quantitatively determine temporal and spatial distribution characteristics of main grain crops in the West Liaohe River basin,Inner Mongolia,China,from 2000 to 2010 based on MODIS remote sensing data and NDVI ... Here,we quantitatively determine temporal and spatial distribution characteristics of main grain crops in the West Liaohe River basin,Inner Mongolia,China,from 2000 to 2010 based on MODIS remote sensing data and NDVI time series information for the years 2000,2005 and 2010.Phenological calendars and a decisionmaking tree extraction model were also used to obtain spatial distribution information of spring maize,spring wheat and soybean.We found that in 2010,the sown area of the main grain crops in the West Liaohe River basin was 11 965.08km2,of which,the sown area for spring maize accounted for 92.28%and was concentrated in the lower reaches of the region.Spring wheat accounted for 3.14% and was mainly in the middle reaches.Soybean accounted for 4.58% and was predominantly in the upper reaches.From 2000 to 2005,the sown area of these grain crops in the West Liaohe River basin grew by 29.77%,mainly in the lower reaches: spring maize grew by 38.99%,spring wheat by 39.04% and soybean by 21.27%.From 2005 to 2010,growth in the sown area of these crops was slow(5.18% growth) and mainly in the lower reaches of the basin.The sown area of spring maize increased,but decreased for both spring wheat and soybean. 展开更多
关键词 MODIS grain crops temporal and spatial distribution pattern West Liaohe River basin MAIZE SOYBEAN wheat.
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Spatial Distribution Patterns and the Evolution Process of Carbon Storage in a Typical Karst Canyon Area 被引量:1
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作者 张斯屿 白晓永 +4 位作者 王世杰 秦罗义 李盼龙 罗光杰 李月 《Journal of Resources and Ecology》 CSCD 2015年第4期199-207,共9页
Qinglong County in Guizhou, China is a typical karst canyon area. Using quadrat methods and a land use transfer matrix we studied the carbon storage spatial distribution pattern and evolution process over three indepe... Qinglong County in Guizhou, China is a typical karst canyon area. Using quadrat methods and a land use transfer matrix we studied the carbon storage spatial distribution pattern and evolution process over three independent periods (1988, 1999 and 2009) in this area. Based on the results we estimated the carbon pool capacity of the entire karst canyon area in Guizhou and contribution ratios. Carbon storage and average carbon density of the karst area in Qinglong decreased at first, and then increased over the sampling period. The actual carbon storage of the karst canyon area in Guizhou was estimated to be 42.55 Tg. The average carbon intensity of the karst canyon area in Guizhou is far higher than that of national terrestrial ecosystems, especially in vegetation areas. Through cross comparison, we found that karst canyon areas have great carbon sequestration potential and we suggest that it is necessary to control and prevent rocky desertification in karst areas in China. 展开更多
关键词 carbon storage evolution process karst canyon spatial distribution patterns
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Identifying urban functional zones by capturing multi-spatial distribution patterns of points of interest 被引量:1
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作者 Quan Qin Shishuo Xu +1 位作者 Mingyi Du Songnian Li 《International Journal of Digital Earth》 SCIE EI 2022年第1期2468-2494,共27页
Urban Functional Zone(UFZ)identification is vital for urban planning,renewal,and development.Point of Interest(POI),as one of the most popular data in UFZ studies,is transformed into a geo-corpus under specific sampli... Urban Functional Zone(UFZ)identification is vital for urban planning,renewal,and development.Point of Interest(POI),as one of the most popular data in UFZ studies,is transformed into a geo-corpus under specific sampling strategies,which can be used with Natural Language Processing(NLP)technology to extract geo-semantic features and identify UFZs.However,existing studies only capture a single spatial distribution pattern of POIs,while ignoring the other spatial distribution information.In this paper,we developed an integrated geo-corpus construction approach to capture multi-spatial distribution patterns of POIs that were represented by different modal POI embeddings.Subsequently,random forest model was leveraged to classify UFZs based on those embeddings.A set of combination experiments were designed for performance validation.The results show that our proposed method can effectively identify UFZs with an accuracy of 72.9%,with an improvement of 8.5%compared to the baseline methods.The outcome of this study will help urban planners to better understand UFZs through investigating the integrated spatial distribution patterns of POIs embedded in UFZs. 展开更多
关键词 Urban functional zone point of interest spatial distribution pattern natural language processing word2vec
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Space-time Distribution Pattern of Monochamus alternatus in Wanding City
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作者 熊忠平 涂玉 司徒英贤 《Plant Diseases and Pests》 CAS 2010年第2期35-37,共3页
[Objective] The purpose was to study space-time distribution pattern of Monochamus alternatus in Wanding City. [Method] Based on data about insect situation supervision on M. alternatus in Wanding City, using related ... [Objective] The purpose was to study space-time distribution pattern of Monochamus alternatus in Wanding City. [Method] Based on data about insect situation supervision on M. alternatus in Wanding City, using related mathematical statistics methods including linear regression analysis and spatial distribution pattern of insect population, the relationship between emergence period, emergence quantity and temperature of M. alternatus adult, spatial distribution pattern of adults and their life history were studied. [Result] M. alternatus occurred one generation per year in Wanding city, June was the maximum period of adults, which was also the key trapping period. Spatial distribution of M. alternatus was accumulative. [Conclusion] This study provided theoretical basis for further control on M. alternatus for forestry bureau of Wanding City. 展开更多
关键词 Wanding Monochamus alternatus Life history spatial distribution pattern
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Population structure and distribution pattern of Taxus cuspidata in Muling region of Heilongjiang Province, China 被引量:9
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作者 ZU Yuan-gang CHEN Hua-feng WANG Wen-jie NIE Shao-quan 《Journal of Forestry Research》 SCIE CAS CSCD 2006年第1期80-82,共3页
An investigation was conducted on distribution pattern, site condition and population structure of yew Taxus cuspidata Sieb. et Zucc. in Muling Forest Bureau of Heilongjiang Province, China in April, 2005. Results sho... An investigation was conducted on distribution pattern, site condition and population structure of yew Taxus cuspidata Sieb. et Zucc. in Muling Forest Bureau of Heilongjiang Province, China in April, 2005. Results showed that yew is mainly distributed under the main storey of natural mixed forest of conifer and broadleaf, the soil moisture content of the yew site is high (40%-60%), the pH value of soil is relatively lower (4.7-5.5), and that the population structure of wild yew is not rational, belonging to the degeneration population, which is one of the reasons leading to the population decline. Although the site conditions of Muling area are suitable for the growth of wild yew, the population of wild yew shows a decline tendency, due to the fact that the middle-sized adult yew trees have been cut, young yews are often grazed by wildlife, and that the trunks of adult yew tend to be hollow. 展开更多
关键词 Taxus cuspidata Sieb. et Zucc. YEW Population structure spatial distribution pattern Site conditions
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Spatial patterns of farmland abandonment and its impact factors in the central Three Gorges Reservoir Area 被引量:6
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作者 CHEN Ying-feng WANG Yu-kuan +2 位作者 FU Bin WANG Hai-wen WANG Wei 《Journal of Mountain Science》 SCIE CSCD 2018年第3期631-644,共14页
The severe farmland abandonment phenomena in China have tremendously decreased the farmland usage efficiency and caused a series of profound ecological and social outcomes. The complexity of farmland abandonment neces... The severe farmland abandonment phenomena in China have tremendously decreased the farmland usage efficiency and caused a series of profound ecological and social outcomes. The complexity of farmland abandonment necessitates a systematic research on its patterns and impact factors to underpin the dynamics of problem as well as potential solutions. This paper took Wanzhou district in the central part of Three Gorges Reservoir Area as an example to study the spatial distribution patterns of abandoned farmland at three scales, i.e., town, village, and plot, and analyzed the influence from labor transfer and farmland circulation. We conducted a survey on the distribution patterns of abandoned farmland via questionnaires at town and village scales, together with the modeling and interpretation of high-resolution aerial images taken by unmanned aerial vehicles at plot scale. Our research discloses a strong relationship between the distribution of abandoned farmland and the distance from population center at different scales. At eithertown or village scale, the abandonment proportion was recognized the highest in mid-distance areas and lowest in close-distance areas, and the per capita area of abandoned farmland increased with the distance to downtown or township. At plot scale, abandonment proportion presented exponential growth with the distance to village center, whereas the abandoned farmland was mainly distributed in the areas with distance above 500 m from the village center. Moreover, we noticed that labor transfer and farmland circulation are two important factors that influence farmland abandonment. Labor's outbound transfer distance has a positive linkage with the possibility of farmland abandonment. Finally, it is recommended that development and adoption of corresponding policies on local urbanization and farmland circulation will facilitate to alleviate farmland abandonment. 展开更多
关键词 Three Gorges Reservoir Area Farmland abandonment spatial distribution pattern Labor transfer Cultivated farmland MULTI-SCALE Unmanned aerial vehicle
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Population structure and spatial pattern analysis of Quercus aquifolioides on Sejila Mountain,Tibet,China 被引量:2
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作者 Zhiqiang Shen Jie Lu +4 位作者 Min Hua Xiaoqin Tang Xingle Qu Jingli Xue Jiangping Fang 《Journal of Forestry Research》 SCIE CAS CSCD 2018年第2期400-409,共10页
Understanding population structure provides basic ecological data related to species and ecosystems.Our objective was to understand the mechanisms involved in the maintenance of Quercus aquifolioides populations.Using... Understanding population structure provides basic ecological data related to species and ecosystems.Our objective was to understand the mechanisms involved in the maintenance of Quercus aquifolioides populations.Using a 1 ha permanent sample plot data for Q.aquifolioides on Sejila Mountain,Tibet Autonomous Region(Tibet),China,we analyzed the population structure of Q.aquifolioides by combining data for diameter class,static life table and survival curve.Simultaneously,the spatial distribution of Q.aquifolioides was studied using Ripley’s L Function in point pattern analysis.The results showed:(1) Individuals in Q.aquifolioides populations were mainly aggregated in the youngest age classes,that accounted for94.3% of the individuals; the older age classes had much smaller populations.Although the youngest age classes(ClassesⅠ and Ⅱ) had fewer individuals than Class Ⅲ,the total number of individuals in classes Ⅰ and Ⅱ was also greater than in classes Ⅳ to Ⅸ.In terms of tree height,fewsaplings,more medium-sized saplings and few large-sized trees were found.The diameter class structure of Q.aquifolioides populations formed an atypical ‘pyramid’type; the population was expanding,but growth was limited,tending toward a stable population.(2) Mortality of Q.aquifolioides increased continuously with age; life expectancy decreased over time,and the survivorship curve was close to a Deevey I curve.(3) The spatial distribution pattern of Q.aquifolioides varied widely across different developmental stages.Saplings and medium-sized tree showed aggregated distributions at the scales of 0–33 m and 0–29 m,respectively.The aggregation intensities of saplings and medium-sized trees at small scales were significantly stronger than that of large-sized trees.However,large-sized trees showed a random distribution at most scales.(4) No correlation was observed among saplings,medium-and large-sized trees at small scales,while a significant and negative association was observed as the scale increased.Strong competition was found among saplings,medium-and large-sized trees,while no significant association was observed between medium-and largesized trees at all scales.Biotic interactions and local ecological characteristics influenced the spatial distribution pattern of Q.aquifolioides populations most strongly. 展开更多
关键词 Point pattern analysis Population structure Quercus aquifolioides Sejila Mountain spatial distribution pattern
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Spatial pattern analysis and associations of different growth stages of populations of Abies georgei var.smithii in Southeast Tibet,China 被引量:3
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作者 SHEN Zhi-qiang LU Jie +1 位作者 HUA Min FANG Jiang-ping 《Journal of Mountain Science》 SCIE CSCD 2016年第12期2170-2181,共12页
Abies georgei var.smithii is an important plant species in Southeast Tibet,China.It has high ecological value in terms of biodiversity protection,as well as soil and water conservation.We analyzed the spatial pattern ... Abies georgei var.smithii is an important plant species in Southeast Tibet,China.It has high ecological value in terms of biodiversity protection,as well as soil and water conservation.We analyzed the spatial pattern and associations of A.georgei var.smithii populations at different growth stages by using Ripley's L function for point pattern analysis.The diameter structure was a nearly reverse 'J' shape.The amount of saplings and medium-sized trees accounts for a large part of the entire population,suggesting a high regeneration rate and an expanding population.In the transition from saplings to medium trees or to large trees,saplings show a significant aggregation distribution at small scales,while medium trees and large trees show a random distribution.There are significant inverse associations between saplings and medium trees and large trees at small scales,while there are no obvious associations between medium trees and large trees.The natural regeneration was affected by interspecific competition,and it was also affected by intraspecific competition.The joint effects of biological characteristics and environmental factors contribute to the spatial distribution pattern and associations of this A.georgei var.sm ithii population. 展开更多
关键词 Southeastern Tibet Abies georgei var.smithii Point pattern analysis distribution pattern spatial association
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Spatial Pressure Distribution of Cultivated Land and the Analysis of Food Safety in Kunming City,China
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作者 PENG Er-rui WANG Sui +3 位作者 LV Xia ZHANG Jian-sheng ZHANG Chuan HAO Li-sha 《Asian Agricultural Research》 2010年第2期53-56,共4页
The social and economical condition,cultivated land resources and general situation of grain production of research area are introduced.According to relevant data of cultivated land of Kunming City in 2006,taking the ... The social and economical condition,cultivated land resources and general situation of grain production of research area are introduced.According to relevant data of cultivated land of Kunming City in 2006,taking the minimum per capita cultivated land and index model of cultivated land pressure,and combining with two conditions of per capita grain demand which are 300 kg and 400 kg,the comparative research method was used to calculate and analyze the minimum per capita cultivated land and index model of cultivated land pressure.The results show that when per capita grain demand-Gr is 300 kg,the per capita cultivated land in Kunming City has regional differences,reflects different regular patterns of spatial distribution,and presents obvious and typical radial distribution.Urban area of Kunming has the lowest point and be taken as the center,per capita cultivated land decreases progressively from suburban to the periphery;when per capita grain demand-Gr is 400 kg,under the same consumption level,cultivated land pressures of each county in Kunming City are different,and so are the driven factors;when per capita grain demand-Gr is 300 kg or 400 kg,the indexes of cultivated land pressure in Kunming are all greater than 1,cultivated land pressure is enormous,the indexes of cultivated land pressure of each county(district) have two conditions-greater than 1 and less than 2,and the reasons differ from one another.Combining with the spatial distribution characteristics of the cultivated land and food and the situation of industrial development,the countermeasures and suggestions are put forwarded to make full use of back-up cultivated land,to plan the distribution of industrial structure in each county(district) of Kunming City as a whole,to dispose cultivated land resources reasonably and so on. 展开更多
关键词 Food safety Index model of cultivated land pressure Minimum per capita cultivated land Regular pattern of spatial distribution China
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A new methodology for estimating forest NPP based on forest in-ventory data——a case study of Chinese pine forest 被引量:6
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作者 赵敏 周广胜 《Journal of Forestry Research》 SCIE CAS CSCD 2004年第2期93-100,i001,共9页
Accurately estimating forest net primary productivity (NPP) plays an important role in study of global carbon budget. A NPP model reflecting the synthetic effects of both biotic (forest stand age, A and stem volume, V... Accurately estimating forest net primary productivity (NPP) plays an important role in study of global carbon budget. A NPP model reflecting the synthetic effects of both biotic (forest stand age, A and stem volume, V) and climatic factors (mean annual actual evapotranspiration, E) was developed for Chinese pine (Pinus tabulaeformis) forest by making full use of Forest Inventory Data (FID) and dynamically assessing forest productivity. The NPP of Chinese pine forest was estimated by using this model and the fourth FID (1989–1993), and the spatial pattern of NPP of Chinese pine forest was given by Geography Information System (GIS) software. The results indicated that mean NPP value, of Chinese pine forest was 7.82 t m?2·a?1 and varied at the range of 3.32–11.87 t hm?2·a?1. NPP distribution of Chinese pine forests was significantly different in different regions, higher in the south and lower in the north of China. In terms of the main distribution regions of Chinese pine, the NPPs of Chinese pine forest in Shanxi and Shaanxi provinces were in middle level, with an average NPP of 7.4 t hm?2·a?1, that in the southern and the eastern parts (e.g. Shichuang Hunan, Henan, and Liaoning provinces) was higher (over 7.7 t hm?2·a?1), and that in the northern part and western part (e.g. Neimenggu and Ningxia provinces) was lower (below 5 t hm?2·a?1). This study provides an efficient way for using FID to understand the dynamics of foest NPP and evaluate its effects on global climate change. Keywords Forest NPP - Forest inventory data - Chinese pine forest - Climatic and biotic NPP model - Spatial distribution pattern CLC number S727.22 - S757.2 Document code A Foundation item: This study was supported by the National Natural Science Foundation of China (Nos. 30028001, 49905005), National Key Basic Research Specific Foundation (G1999043407); the Chinese Academy of Sciences (KSC2-1-07).Biography: ZHAO Min (1973-), female, Ph. D. in Laboratory of Quantitative Vegetation Ecology, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, P. R. China.Responsible editor: Zhu Hong 展开更多
关键词 Forest NPP Forest inventory data Chinese pine forest Climatic and biotic NPP model spatial distribution pattern
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Fine-scale genetic structure of Eremosparton songoricum and implication for conservation 被引量:6
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作者 Liu, Yan Zhang, DaoYuan +2 位作者 Yang, HongLan Liu, MeiYing Shi, Xiang 《Journal of Arid Land》 SCIE 2010年第1期26-32,共7页
Eremosparton songoricum (Litv.) Vass. is a clonal shrub that reproduces both asexually by under-ground rhizomes and sexually by seeds. It is now a rare species with a narrow distribution in fragmented habitat patches ... Eremosparton songoricum (Litv.) Vass. is a clonal shrub that reproduces both asexually by under-ground rhizomes and sexually by seeds. It is now a rare species with a narrow distribution in fragmented habitat patches in the Gurbantunggut Desert of Xinjiang, China. The objective of this study was to determine the spatial pattern or structure of genetic variation within population. The within-populations genetic structure of E. songoricum in a plot (10 m×10 m) was analyzed using inter simple sequence repeats (ISSR) markers. Correlograms of Moran’s I showed significant positive value was about 7 m, but changed into a negative correlation with the increase of distance, indicating strong genetic structure. The natural character of clonal reproduction, restricted seed and pollen dispersal were the main factors of influencing the spatial pattern. The knowledge of clonal structures within populations was crucial for understanding evolutionary processes and ecological adaptation. This study provided basic data for the conservation and management of E. songoricum, especially for sampling strategies for ex situ conservation. 展开更多
关键词 Eremosparton songoricum genetic diversity clonal structure spatial distribution patterns CONSERVATION
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Influence of vegetation cover and other sources of variability on sediment and runoff response in a burned forest in South Korea 被引量:1
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作者 EWANE Basil Ewane LEE Heon-Ho 《Journal of Mountain Science》 SCIE CSCD 2017年第2期296-315,共20页
Post-fire field measurements of sediment and run off yield were undertaken in natural rainfall event-basis during five rainy months in Korea on a total of 15 small plots: four replica burned unseeded plots, six replic... Post-fire field measurements of sediment and run off yield were undertaken in natural rainfall event-basis during five rainy months in Korea on a total of 15 small plots: four replica burned unseeded plots, six replica burned seeded plots, and five replica unburned plots. The main aim was to evaluate the effects of vegetation recovery and spatial distribution patterns on sediment and runoff response between and within the treatment replica erosion plots. Sixyears after the wildfire, total sediment and runoff yield in the burned unseeded plots with 20%-30%vegetation cover was still 120.8 and 20.6 times higher than in the unburned treatment plots with 100%ground cover, 8.3 and 6.7 times higher than in the burned seeded plots with 70%-80% vegetation cover,while only 1.6 and 2.0 times higher than in the burned seeded plots with 50%-60% vegetation cover,respectively. The differences in sediment and runoff yield between the treatment plots was proportional to total vegetation cover, distance of bare soil to vegetation cover, magnitude of rainfall characteristics and changes in soil properties, but not slope gradient.Three out of the six within-treatment pairs of two replica plots showed large differences in sediment and runoff yield of up to 6.0 and 4.2 times and mean CV of up to 99.1% and 62.2%, respectively. This was due to differences in the spatial distribution patterns of surface cover features, including aggregation of vegetation and litter covers, the distance of bare soil exposed to vegetation cover closer to the plot sediment collector and micro topographic mounds and sinks between pairs of replica plots. Small differences in sediment and runoff of only 0.9-1.4folds and mean CV of 8.6%-25% were observed where the within-treatment pairs of replica plots had similar slope, total surface cover components and comparable spatial distribution pattern of vegetation and bare soil exposed surface covers. The results indicated that post-fire hillslopes undergoing effective vegetation recovery have the potential to reduce sediment and runoff production nearer to unburned levels within 6-years after burning while wildfire impacts could last more than 6-years on burned unseeded ridge slopes undergoing slow vegetation recovery. 展开更多
关键词 Bare soil exposed Vegetation cover Post-fire Soil erosion spatial distribution patterns Replica erosion plots
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