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Classification and Spatial Pattern of Township Development in Liaoning Province, China
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作者 LIU Xiaohui ZHENG Xingming +1 位作者 LIU Wenxin CHEN Xinyu 《Chinese Geographical Science》 SCIE CSCD 2023年第4期708-718,共11页
The classification of township development types is an urgent problem that requires solution to enable the township to choose an appropriate development path.Using a township development classification method,we deter... The classification of township development types is an urgent problem that requires solution to enable the township to choose an appropriate development path.Using a township development classification method,we determine the township development types and their spatial patterns in Liaoning Province,China.The results showed that the patterns of township development types based on their general advantages had significant spatial differentiations.The planting,and livestock and poultry breeding township development types based on general advantages were mainly distributed across the central plain of Liaoning Province,China,and also concentrated in Dandong City−Dalian City along Yellow Sea coast,and in the northwest of Chaoyang City.The business and tourism,industry and mining,and residence township development types based on general advantages were distributed mainly along the Shenyang–Dalian Economic Belt in the central and southern Liaoning Province.The ecology township development type based on general advantages was mainly distributed in the eastern and western Liaoning Province to maintain regional ecological security.Township development types based on non-advantages were sporadically distributed in the middle and western Liaoning Province.Based on the classification and spatial patterns,the differences between the distribution of twonship development types and the plan for the major functional areas of Liaoning Province were proposed which could provide the basis for the optimization of the major functional areas. 展开更多
关键词 general advantage township development type spatial pattern Liaoning Province China
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The Spatial Patterns of Road Traffic Crash Black Spots and Emergency Facilities in Federal Capital City
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作者 Mamman Saba Jibril David Sesugh Aule Badiatu Danladi Garba 《Journal of Geoscience and Environment Protection》 2023年第2期121-134,共14页
This study aimed at determining the spatial patterns of Road Traffic Crash (RTC) black spots, Federal Road Safety Commission (FRSC) zebra points and emergency health care facilities in Federal Capital City (FCC). The ... This study aimed at determining the spatial patterns of Road Traffic Crash (RTC) black spots, Federal Road Safety Commission (FRSC) zebra points and emergency health care facilities in Federal Capital City (FCC). The aim was to provide stakeholders with information that will aid their understanding of accident prone locations and accessible rescue possibilities for accident victims on the roads in FCT. GPS Map 76S Mark (GARMIN) was used to locate and pick coordinates of data in the study area. A total of 16 possible emergency health care facilities, seventy (70) RTC black spots and Five Zebra point locations were obtained from FRSC. ArcGIS 10.0 was used to compute the data by plotting the coordinates to produce maps of the spatial relationship and to carry out Nearest Neighbour Analysis (NNA). The result was further used to determine the spatial patterns of RTC black spots as well as patterns of the emergency facilities. Generally, the result shows that the spatial trend is turning towards dispersion. However, there is less than 1% likelihood that the dispersed patterns could be the result of random chance. It was recommended that, the Federal Road Safety Commission should be staffed with trained professionals that can be responsible for accident data surveillance and analysis using geospatial techniques. 展开更多
关键词 ACCIDENT Black Spot EMERGENCY pattern spatial Zebra Point
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The temporal and spatial patterns and potential evaluation of China's energy resources development 被引量:8
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作者 MA Beibei LU Chunxia +1 位作者 ZHANG Lei CHENG Xiaoling 《Journal of Geographical Sciences》 SCIE CSCD 2010年第3期347-356,共10页
The issue of China's energy supply security is not only the key problem which af- fects China's rapid and sustainable development in the 21st century, but also the one which international attention focuses on. Based... The issue of China's energy supply security is not only the key problem which af- fects China's rapid and sustainable development in the 21st century, but also the one which international attention focuses on. Based on the notable characteristic of spatial imbalance between energy production and consumption in China, this paper takes the evolution of China's primary energy resources development(excluding hydropower) from 1949 to 2007 as the study object, with the aim to sum up the evolutive characteristics and laws of China's energy resources development in the past nearly 60 years. Then, based on comprehensive considerations of coal's, oil's and natural gas's basic reserves, qualities, geological conditions production status, and ecological service function of every province, this paper adopts development potential index (DP)to evaluate the development potential of every province's en- ergy resources, and divide them into different ranks. Conclusions are drawn as follows: (1) Generally speaking, China's gross energy production was increasing in waves from 1949 to 2007. From the viewpoint of spatial patterns, China's energy resources development has shown a characteristic of "concentrating to the north and central areas, and evolving from linear-shaped to "T-shaped" pattern gradually since 1949. (2) The structure evolution of China's energy resources development in general has shown a trend of "coal proportion is dominant but decreasing, while oil and gas proportions are increasing" since 1949. (3) At the provincial scale, China's energy resources development potential could be divided into large, sub-large, general and small ranks, four in all. In the future, the spatial pattern of China's energy production will evolve from "T-shaped" to "R-shaped pattern". These conclusions will help to clarify the temporal and spatial characteristics and laws of China's energy resources development, and will be beneficial for China to design scientific and rational energy development strategies and plans, coordinate spatial imbalance of energy production and consumption, ensure national energy supply, avoid energy resources waste and disorderly development, and promote regional sustainable development under the globalization back-ground with changeful international energy market. 展开更多
关键词 energy resources development temporal and spatial patterns potential evaluation China
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Characteristics of Temperature Change in China over the Last 2000 years and Spatial Patterns of Dryness/Wetness during Cold and Warm Periods 被引量:10
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作者 Quansheng GE Haolong LIU +2 位作者 Xiang MA Jingyun ZHENG Zhixin HAO 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2017年第8期941-951,共11页
This paper presents new high-resolution proxies and paleoclimatic reconstructions for studying climate changes in China for the past 2000 years. Multi-proxy synthesized reconstructions show that temperature variation ... This paper presents new high-resolution proxies and paleoclimatic reconstructions for studying climate changes in China for the past 2000 years. Multi-proxy synthesized reconstructions show that temperature variation in China has exhibited significant 50–70-yr, 100–120-yr, and 200–250-yr cycles. Results also show that the amplitudes of decadal and centennial temperature variation were 1.3℃ and 0.7℃, respectively, with the latter significantly correlated with long-term changes in solar radiation, especially cold periods, which correspond approximately to sunspot minima. The most rapid warming in China occurred over AD 1870–2000, at a rate of 0.56°± 0.42℃(100 yr)^(-1); however, temperatures recorded in the 20 th century may not be unprecedented for the last 2000 years, as data show records for the periods AD 981–1100 and AD1201–70 are comparable to the present. The ensemble means of dryness/wetness spatial patterns in eastern China across all centennial warm periods illustrate a tripole pattern: dry south of 25°N, wet from 25°–30°N, and dry to the north of 30°N. However, for all centennial cold periods, this spatial pattern also exhibits a meridional distribution. The increase in precipitation over the monsoonal regions of China associated with the 20 th century warming can primarily be attributed to a mega El Nino–Southern Oscillation and the Atlantic Multidecadal Oscillation. In addition, a significant association between increasing numbers of locusts and dry/cold conditions is found in eastern China. Plague intensity also generally increases in concert with wetness in northern China, while more precipitation is likely to have a negative effect in southern China. 展开更多
关键词 temperature change dry-wet spatial pattern cold and warm periods last 2000 years China
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Common Spatial Pattern Ensemble Classifier and Its Application in Brain-Computer Interface 被引量:5
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作者 Xu Lei Ping Yang Peng Xu Tie-Jun Liu De-Zhong Yao 《Journal of Electronic Science and Technology of China》 2009年第1期17-21,共5页
Abstract-Common spatial pattern (CSP) algorithm is a successful tool in feature estimate of brain-computer interface (BCI). However, CSP is sensitive to outlier and may result in poor outcomes since it is based on... Abstract-Common spatial pattern (CSP) algorithm is a successful tool in feature estimate of brain-computer interface (BCI). However, CSP is sensitive to outlier and may result in poor outcomes since it is based on pooling the covariance matrices of trials. In this paper, we propose a simple yet effective approach, named common spatial pattern ensemble (CSPE) classifier, to improve CSP performance. Through division of recording channels, multiple CSP filters are constructed. By projection, log-operation, and subtraction on the original signal, an ensemble classifier, majority voting, is achieved and outlier contaminations are alleviated. Experiment results demonstrate that the proposed CSPE classifier is robust to various artifacts and can achieve an average accuracy of 83.02%. 展开更多
关键词 Brain-computer interface channel selection classifier ensemble common spatial pattern.
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THE TEMPORAL AND SPATIAL PATTERNS OF ENVIRONMENTAL RISK EVENTS IN THE PAST 30 YEARS IN SHENYANG CITY
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作者 Bi Jun Tang Yijian Zhang Shen(Institute of Geography, CAS, Beijing 100101People’s Republic of China)Wang Huadong(Institute of Environmental Sciences, Beijing Normal University, Beijing 100875People’s Republic of China) 《Journal of Geographical Sciences》 SCIE CSCD 1995年第1期76-86,共11页
The index of Risk Frequency (RF) and other relative indices are used to analyze the temporal and spatial patterns of environmental riskevents in the past 30 years in Shenyang city. The results show that thereexists si... The index of Risk Frequency (RF) and other relative indices are used to analyze the temporal and spatial patterns of environmental riskevents in the past 30 years in Shenyang city. The results show that thereexists significant difference of the RFs between periods of 1966-1977 and1978-1991 (t=7.353**, t0.01=2.807). During the past 30 years, there areno significant changes of the spatial patterns of the environmental risk,while the proportions of environmental risk among the districts are extremely different. In Shenyang city, there exists a series of high riskenterprises, and the chemical industry is the one with highest risk. 展开更多
关键词 environmental risk events temporal and spatial patterns risk frequency
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A township-level assessment of forest fragmentation using morphological spatial pattern analysis in Qujing,Yunnan Province,China
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作者 HUANG Xiao-yuan YE Yuan-hui +4 位作者 ZHANG Zhuo-ya YE Jiang-xia GAO Jie Marc BOGONOVICH ZHANG Xing 《Journal of Mountain Science》 SCIE CSCD 2021年第12期3125-3137,共13页
Forest fragmentation is an integral part of global change.Understanding forest fragmentation patterns and dynamics are of great significance for maintaining ecosystem stability.There are great differences in the inter... Forest fragmentation is an integral part of global change.Understanding forest fragmentation patterns and dynamics are of great significance for maintaining ecosystem stability.There are great differences in the interference of natural and human factors on forests in different towns of mountainous cities,and the characteristics of forest fragmentation are also obviously different.Forest fragmentation has been broadly studied,yet,it remains poorly understood at the township-scale within mountainous cities.In this study,the spatial form of forest landscape and forest fragmentation modes of towns were examined in Qujing City,Yunnan Province,China for the years of 2006 and 2016,relying heavily on the morphological spatial pattern analysis(MSPA)and K-means clustering algorithm.Results in 2016 showed that the forest landscape morphology of Qujing could be divided into seven classes:core,perforation,islet,bridge,edge,branch and ring;with landscape areas of 41.94%,1.22%,7.04%,11.12%,23.26%,11.74%and 3.68%respectively.Compared with 2006,the changes of landscape area were 1.71%,0.02%,0.30%,1.65%,0.20%,0.19%and 0.05%respectively.The townships in Qujing varied significantly in their landscape fragmentation patterns,and these patterns were spatially dependent.Different forest landscape forms have positive spatial correlations and differences.The forest fragmentation modes of towns can be divided into four types:Low anthropogenic towns,high anthropogenic towns,complex terrain towns and gentle terrain towns.Different ways of human activities play a decisive role in forest landscape fragmentation.The expansion of construction land and agricultural land intensifies forest fragmentation;however,man-made orderly and planned ecological restoration will greatly improve the forest coverage and improve the spatial form of urban forest landscape. 展开更多
关键词 Forest fragmentation Morphological spatial pattern analysis Morphological type China
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Monitoring of Pinus massoniana spatial pattern changes based on RS and GIS techniques
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作者 WANG Lei HUANG Hua-guo ZHANG Xiao-li LUO You-qing SHI Juan 《Forestry Studies in China》 CAS 2008年第1期32-35,共4页
Our research focused on Pinus massoniana information extracted from remote sensing images based on the knowledge detection and decision tree algorithm and established a spatial pattern model, combining quantitative th... Our research focused on Pinus massoniana information extracted from remote sensing images based on the knowledge detection and decision tree algorithm and established a spatial pattern model, combining quantitative theoretical ecology with remote sensing (RS) and geometric information system (GIS) techniques. Applying information extraction methods and a spatial pattern model, we studied P. massoniana spatial patterns changes before and after the invasion by pine wood nematode (Bursaphelenchus xylophilus) in Fuyang and Zhoushan counties, Zhejiang Province, east China. The P. massoniana spatial patterns are clustering, whether the invasion happened or not. But the degree of clustering is different. Our results show good agreement with field data. Applying the results, we analyzed the relationship between spatial patterns and the invasion level. Then we drew the elementary conclusion that there are two kinds of patterns for pine wood nematode to spread: continuous and discontinuous diffusion. This approach can help monitor and evaluate the changes in ecological systems. 展开更多
关键词 Bursaphelenchus xylophilus invasion remote sensing GIS information extraction Pinus massoniana spatial pattern
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Evolution and Spatial Patterns of Spheres of Urban Influence in China 被引量:5
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作者 WANG Kaiyong DENG Yu +1 位作者 SUN Daowei SONG Tao 《Chinese Geographical Science》 SCIE CSCD 2014年第1期126-136,共11页
This article presents the findings of a study of the spheres of urban influence with regard to all cities in China(not including Hong Kong,Macao and Taiwan Province of China)in the years 1990,2000 and 2009.An optimize... This article presents the findings of a study of the spheres of urban influence with regard to all cities in China(not including Hong Kong,Macao and Taiwan Province of China)in the years 1990,2000 and 2009.An optimized gravity model with comprehensive time distance was used to carry out a detailed analysis of the spatial patterns of Chinese spheres of urban influence and the spatial characteristics of urban agglomerations.Such urban agglomerations are characterized by high density population and a developed economy,which are also considered as the national competition unit.This paper initially identifies four spatial patterns of urban agglomerations based on the spatial layout of city groups during their evolution.Some basic characteristics of urban agglomerations are outlined,including the number of cities,the size of cities and the functions of urban centers.These characteristics are examined by using statistical methods and Geographic Information System(GIS).The main findings from this research are that the development stages and structures of urban agglomerations in China vary significantly.It is also clear that the stages and evolution of spatial patterns are strongly affected and dominated by both policy and location factors. 展开更多
关键词 SPHERES of URBAN INFLUENCE types of spatial pattern dynamic EVOLUTION URBAN AGGLOMERATION
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Characterizing Spatial Patterns of Phenology in Cropland of China Based on Remotely Sensed Data 被引量:14
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作者 WU Wen-bin YANG Peng +3 位作者 TANG Hua-jun ZHOU Qing-bo CHEN Zhong-xin Ryosuke Shibasaki 《Agricultural Sciences in China》 CSCD 2010年第1期101-112,共12页
This study used time-series of global inventory modeling and mapping studies (GIMMS) normalized difference vegetation index (NDVI) datasets at a spatial resolution of 8 km and 15-d interval to investigate the spat... This study used time-series of global inventory modeling and mapping studies (GIMMS) normalized difference vegetation index (NDVI) datasets at a spatial resolution of 8 km and 15-d interval to investigate the spatial patterns of cropland phenology in China. A smoothing algorithm based on an asymmetric Gaussian function was first performed on NDVI dataset to minimize the effects of anomalous values caused by atmospheric haze and cloud contamination. Subsequent processing for identifying cropping systems and extracting phenological parameters, the starting date of growing season (SGS) and the ending date of growing season (EGS) was based on the smoothed NVDI time-series data. The results showed that the cropping systems in China became complex as moving from north to south of China. Under these cropping systems, the SGS and EGS for the first growing season varied largely over space, and those regions with multiple cropping systems generally presented a significant advanced SGS and EGS than the regions with single cropping patterns. On the contrary, the phenological events of the second growing season including both the SGS and EGS showed little difference between regions. The spatial patterns of cropping systems and phenology in Chinese cropland were highly related to the geophysical environmental factors. Several anthropogenic factors, such as crop variety, cultivation levels, irrigation, and fertilizers, could profoundly influence crop phenological status. How to discriminate the impacts of biophysical forces and anthropogenic drivers on phenological events of cultivation remains a great challenge for further studies. 展开更多
关键词 PHENOLOGY NDVI time-series cropping systems the starting date of growing season (SGS) the ending date of growing season (EGS) spatial pattern
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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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An overview of the spatial patterns of land surface processes over arid and semiarid regions 被引量:6
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作者 Jian Zeng Jie Shen Qiang Zhang 《Research in Cold and Arid Regions》 2010年第4期288-297,共10页
关键词 land surface radiation processes land surface energy processes spatial pattern arid and semiarid regions
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Identification and spatial patterns of coastal water pollution sources based on GIS and chemometric approach 被引量:3
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作者 ZHOU Feng GUO Huai-cheng LIU Yong HAO Ze-jia 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2007年第7期805-810,共6页
Comprehensive and joint applications of GIS and chemometric approach were applied in identification and spatial patterns of coastal water pollution sources with a large data set (5 years (2000-2004), 17 parameters... Comprehensive and joint applications of GIS and chemometric approach were applied in identification and spatial patterns of coastal water pollution sources with a large data set (5 years (2000-2004), 17 parameters) obtained through coastal water monitoring of Southern Water Control Zone in Hong Kong. According to cluster analysis the pollution degree was significantly different between September-next May (the 1st period) and June-August (the 2nd period). Based on these results, four potential pollution sources, such as organic/eutrophication pollution, natural pollution, mineral/anthropic pollution and fecal pollution were identified by factor analysis/principal component analysis. Then the factor scores of each monitoring site were analyzed using inverse distance weighting method, and the results indicated degree of the influence by various potential pollution sources differed among the monitoring sites. This study indicated that hybrid approach was useful and effective for identification of coastal water pollution source and spatial patterns. 展开更多
关键词 source identification spatial pattern cluster analysis (CA) principal component analysis (PCA) inverse distance weighting (IDW) Hong Kong
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Changes and spatial patterns of eco-environment in the farming-pastoral region of northern China 被引量:2
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作者 JIANG Weiguo LI Jing +2 位作者 LI Jiahong CHEN Yunhao WU Yongfeng 《Journal of Geographical Sciences》 SCIE CSCD 2005年第3期329-336,共8页
This paper firstly selects 10 kinds of indexes to reflect eco-environment background condition and builds the multi-subject spatial database by using ground meteorological data, remote sensing data and DEM. It then di... This paper firstly selects 10 kinds of indexes to reflect eco-environment background condition and builds the multi-subject spatial database by using ground meteorological data, remote sensing data and DEM. It then discusses in detail the methods about evaluating eco-environment background condition and analyzing eco-environment change. The eco-environment background conditions of 1989 and 1999 are synthetically appraised. Finally, the paper analyzes the spatial distribution, quantitative change, the trend of change, the areas of change and the dynamic spatial pattern of eco-environment. The results are as follows: (1) The eco-environment background condition becomes worse from southeast to northwest in the fanning-pastoral region of northern China. (2) The eco-environment background condition deteriorates from 1989 to 1999. (3) In the adjacent areas of Shanxi-Shaanxi-Inner Mongolia-Gansu-Ningxia, Horqin Sandy Land and its peripheries, and eastern Qinghai orovince, eco-environmental deterioration is very serious. 展开更多
关键词 fanning-pastoral region ECO-ENVIRONMENT spatial pattern northern China
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Effect of competition on spatial patterns of oak forests on the Chinese Loess Plateau 被引量:3
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作者 KANG Di DENG Jian +4 位作者 QIN Xiaowei HAO Fei GUO Shujuan HAN Xinhui YANG Gaihe 《Journal of Arid Land》 SCIE CSCD 2017年第1期122-131,共10页
Reforestation or natural forest regeneration is an alternative measure for controlling soil erosion in degraded land on the Chinese Loess Plateau(CLP). However, our understanding of the temporal dynamics and the spa... Reforestation or natural forest regeneration is an alternative measure for controlling soil erosion in degraded land on the Chinese Loess Plateau(CLP). However, our understanding of the temporal dynamics and the spatial patterns of forest regeneration remains inadequate. Two oak forests at different development stages were investigated to determine the spatial patterns of competitions(intraspecies and interspecies) during different successional stages. The intraspecies and interspecies spatial relationships among different tree diameters at breast height were analyzed at multiple scales by Kriging interpolation method and univariate and bivariate O-ring statistics. Our analytical results indicated that self-correlation and competition intensity were relatively high between oak and pine trees in the early development stage of oak forests due to their clumped distributions of heavy seeds. Birch trees had a lower competition in comparison to oak trees although birch was the dominant species. Therefore, asymmetric competition of oak trees was most likely to have led to their edge dispersal and their success in replacing the pioneer species. Asymmetric competition means that larger individuals obtained a disproportionately large share of the resources and suppressed the growth of smaller individuals. Kriging interpolation analysis showed a tendency towards homogenization caused by interspecies competition during the succession of oak forests. Our results demonstrated that the competition was the driving factor in the spatial distribution of oak forests on the CLP. 展开更多
关键词 arid and semi-arid region forest regeneration COMPETITION spatial pattern oak forests
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Canopy gap characteristics and spatial patterns in a subtropical forest of South China after ice storm damage 被引量:2
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作者 LIU Feng YANG Zhi-gao ZHANG Gui 《Journal of Mountain Science》 SCIE CSCD 2020年第8期1942-1958,共17页
The divergent gap characteristics and spatial patterns of canopy gaps created by natural or artificial disturbances can exert a dominant influence on forest structure and composition.However,little research has been c... The divergent gap characteristics and spatial patterns of canopy gaps created by natural or artificial disturbances can exert a dominant influence on forest structure and composition.However,little research has been conducted on the effects of ice storm damage on canopy gaps in subtropical mature forests of South China.In this study,one semi-natural site was dominated by a broad-leaf forest and two managed sites were representative of plantations with coniferous forests.Based on airborne laser scanning data and field evidence across sites,statistical analyses were used to examine gap characteristics following ice storms of moderate severity.Generalized Ripley’s K-function analysis was applied to test gap spatial patterns at a range of scales,and spatial point pattern analysis was used to quantitate the relative importance of specific influences on patterns of gap occurrence.The results revealed that the average gap size was 75.7 m^2 and that 12.2 gaps occurred per hectare.Most gaps were single-tree fall events.In addition to more gaps,the mean gap size was smaller and the shape was more complex in the semi-natural site than in two managed sites.Large differences in gap characteristics were observed among snapped,uprooted,snag,and artificial gap damage types.Gaps generally showed a clustered distribution at large scales(e.g.70 m),whereas spatial patterns varied with gap damage types at different sites.The occurrence of gaps was strongly related to slope and topographic position at the semi-natural site,whereas slope,stem density,and human accessibility(proximity to pathways)were the most important factors affecting gap occurrence at the managed sites.We suggest that gap-based silvicultural treatments and natural disturbances regimes conjoin,highlighting interactions with other factors such as microsite conditions,non-tree vegetation and more. 展开更多
关键词 Canopy gap DISTURBANCE spatial point pattern Influence factors SILVICULTURE
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Population structures and spatial patterns of two unpalatable Arisaema species(Araceae) with and without clonal reproduction in a riparian forest intensively grazed by Sika deer 被引量:1
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作者 Tetsuya K.Matsumoto Muneto Hirob +1 位作者 Yasuaki Akaji Yuko Miyazaki 《Journal of Forestry Research》 SCIE CAS CSCD 2020年第1期155-162,共8页
General decline of understory cover can result from increased abundance of and foraging pressure by deer.But population size and degree of aggregation can increase for unpalatable understory plants that escape foragin... General decline of understory cover can result from increased abundance of and foraging pressure by deer.But population size and degree of aggregation can increase for unpalatable understory plants that escape foraging pressure.Clonal reproduction can enable unpalatable plant species to increase their population sizes while trending toward spatially aggregated distributions.However,the details of the relationship between clonal reproduction in unpalatable plants and their dynamics under intensive deer herbivory are not clear.We compared the population structures and spatial patterns of two coexisting unpalatable plant species,Arisaema ovale(with clonal reproduction)and A.peninsulae(without clonal reproduction)in a riparian forest intensively grazed by Sika deer,and examined the null hypothesis that the extent of spatial aggregation and local population size would not differ between the clonal and non-clonal Arisaema species.In a 0.36-ha plot,A.ovale had a larger population size(1087 individuals)with a higher abundance ratio of small plants(p<0.01)than A.peninsulae(84 individuals).Analyses of spatial point processes showed that both populations were spatially aggregated(p<0.05).The spatial aggregation of A.peninsulae,however,became weaker than that of A.ovale,when we excluded one dense patch originating from irregular seed dispersion.These results,excluding the aggregated distribution observed in A.peninsulae,suggested a substantial contribution of clonal reproduction to the expansion of the local A.ovale population following intensive grazing by Sika deer. 展开更多
关键词 Arisaema ovale Arisaema peninsulae Deer herbivory spatial pattern Unpalatable plant
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Quantitative division of succession and spatial patterns among different stand developmental stages in Changbai Mountains 被引量:1
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作者 GONG Zhi-wen KANG Xin-gang GU Li 《Journal of Mountain Science》 SCIE CSCD 2019年第9期2063-2078,共16页
Broadleaf-Korean pine forests exhibit high species richness and distinctive species composition, which are currently becoming more dominant among natural forests in Changbai Mountains of northeastern China. Understand... Broadleaf-Korean pine forests exhibit high species richness and distinctive species composition, which are currently becoming more dominant among natural forests in Changbai Mountains of northeastern China. Understanding the ecological process of restored vegetation is quite important for ecosystem reconstruction. Distinguishing stand development stages and analyzing the dynamic spatial patterns could provide insights into significant community coexistence mechanisms. In the present study, eight permanent study areas were established according to the substituting space for time method in Changbai Mountains of north-eastern China. The optimal division method was used to quantify the successional series into different stand development stages, and the point pattern analysis method(L(r) function) was used to analyse the dynamic changes in spatial patterns and interspecific associations. Our results suggested that:(1) The stand development process was divided into five stages: the first three stages were poplar-birch secondary forests in different stages of recovery, the fourth stage was thespruce-fir mixed forest, and the last stage was the primary broadleaf-Korean pine forest;(2) The spatial pattern showed an aggregated distribution at a small scale and changed to a random distribution as the scale increased in poplar-birch secondary forests, but the spatial pattern appeared to be randomly distributed in spruce-fir mixed forest and broadleafKorean pine forest;(3) The interspecific associations between pioneer species and climax species changed from negative to positive among the different stand stages, and environmental resources were shared among these species. Interspecific differences in shade tolerance among the tree species were key determinants of forest dynamics and structure. Our study is vital to the understanding of the forest development;thus, the spatial change features should receive greater attention when forest management is being planned and restoration strategies are being developed for the Changbai Mountains. 展开更多
关键词 Dynamic spatial patterns INTERSPECIFIC association Optimal DIVISION method STAND DEVELOPMENTAL STAGES Space for time substitution
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Characterizing Spatial Patterns of Precipitation Based on Corrected TRMM_3B_(43) Data over the Mid Tianshan Mountains of China 被引量:9
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作者 JI Xuan CHEN Yunfang 《Journal of Mountain Science》 SCIE CSCD 2012年第5期628-645,共18页
The poor distribution of meteorological stations results in a limited understanding of the precipitation pattern in the Tianshan Mountains. The spatial patterns of precipitation over the mid Tianshan Mountains were ch... The poor distribution of meteorological stations results in a limited understanding of the precipitation pattern in the Tianshan Mountains. The spatial patterns of precipitation over the mid Tianshan Mountains were characterized based on the TRMM 3B43 monthly precipitation data. By comparing satellite estimates with observed data, it shows that TRMM 3B43 data underestimate the precipitation in mountain region. Regression models were developed to improve the TRMM 3B43 data, using geographic location and topographic variables extracted from DEM using GIS technology. The explained variance in observed precipitation was improved from 64% (from TRMM 3B43 products alone) to over 82% and the bias reduced by over 30% when location and topographic variables were added. We recalculated all the TRMM 3B43 monthly precipitation grids for the period 1998 to 2009 using the best regression models, and then studied the variation patterns of precipitation over the mid Tianshan Mountains. The results are well explained by a general understanding of the patterns of precipitation and orographic effects. This indicated that the Tianshan Mountains strongly influences the amount and distribution of precipitation in the region. This is highlighted by the confinement of the precipitation maxima to the windward (northern slope). And complex vertical changes in the provenance and distribution of precipitation, like that a negative increasing rate of precipitation in the vertical direction exists in the north but does not in south. The results have also revealed large gradients and different patterns in seasonal precipitation that are not simply related to elevation, the distribution of precipitation may also be affected by other seasonal factors such as the sources of moist air, wind direction and temperature. 展开更多
关键词 降水规律 TRMM 空间格局 中天山 基础 卫星观测数据 季节性因素 特性
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Multi-scale Spatial Patterns and Influencing Factors of Rural Poverty:A Case Study in the Liupan Mountain Region, Gansu Province, China 被引量:5
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作者 MA Zhenbang CHEN Xingpeng CHEN Huan 《Chinese Geographical Science》 SCIE CSCD 2018年第2期296-312,共17页
The important role of spatial scale in exploring the geography of poverty as well as its policy implications has been noticed but with limited knowledge. To improve such limited understanding, we mainly investigated t... The important role of spatial scale in exploring the geography of poverty as well as its policy implications has been noticed but with limited knowledge. To improve such limited understanding, we mainly investigated the spatial patterns and influencing factors of rural poverty(indicated by poor population and poverty incidence) at three different administrative levels in the Liupan Mountain Region, one of the fourteen poorest regions in China. Our results show that from a global perspective, poor areas are clustered significantly at the county-, township-, and village-level, and more greatly at a lower level. Locally, there is spatial mismatch among poverty hotspots detected not only by the same indicator at different levels but also by different indicators at the same level. A scale effect can be found in the influencing factors of rural poverty. That is, the number of significant factors increases, but the degree of their association with poverty incidence decreases at a lower level. Such scale effect indicates that poverty incidence at lower levels may be affected by more complex factors, including not only the new local ones but also the already appeared non-local ones at higher levels. However, the natural conditions tend to play a scale-independent role to poverty incidence. In response to such scale-dependent patterns and factors, anti-poverty policies can be 1) a multilevel monitoring system to reduce incomplete or even misleading single-level information and understanding; 2) the village-based targeting strategy to increase the targeting efficiency and alleviate the mentioned spatial mismatch; 3) more flexible strategies responding to the local impoverishing factors, and 4) different task emphasises for multilevel policymakers to achieve the common goal of poverty reduction. 展开更多
关键词 空间模式 影响因素 贫穷 农村 山区 中国 多尺度 案例
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