检索结果-南通市图书馆

spatial patterns of the main trees in a plant micro-reserve constructed in the 2022 Beijing Winter Olympics mountainous competition zone

引用

Journal of Mountain Science 2023年第8期20卷 2228-2241页

作者： WANG Jian-yong ZHANG Zhi-xiang School of Ecology and Nature Conservation Beijing Forestry UniversityBeijing 100083China

Several plant micro-reserves were established to preserve the vegetation in local mountain areas during the construction of the Yanqing competition zone of the 2022 Beijing Winter Olympics.The spatial patterns of the main species in one of the micro-reserves and the factors affecting these patterns were characterized in this study.The distribution of arbor species was found to be mostly aggregated,especially at fine scales(spatial patterns were found to be affected by habitat heterogeneity,intraspecific relationships,interspecific competition,and seed dispersal limitation.Habitat heterogeneity was found to affect large-scale spatial patterns,and its effects were observed throughout population development.Interspecific competition is another factor affecting the distribution of the species,and its effects were stronger during the later stages of population development.Habitat heterogeneity was found to affect competition among species and is key for species coexistence.Both these processes are affected by the seed dispersal limitation,and intraspecific relationships are a legacy of seed dispersal.The point patterns can be used as a tool for the initial assessment of the status of communities within micro-reserves.The consideration of these relationships in the development,management,and formulation of policies for micro-reserves in mountainous areas will facilitate the achievement of conservation goals.The careful consideration of habitat conditions when selecting sites for micro-reserves establishment can promote species conservation.

关键词： spatial patterns Point patterns Microreserve Juglans mandshurica forest Beijing mountainous area

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

spatial patterns of phytoplankton communities in an International Seabed Authority licensed area(COMRA,Clarion-Clipperton Zone)in relation to upper ocean biogeochemistry

引用

Acta Oceanologica Sinica 2022年第11期41卷 45-57页

作者： Yu Wang Aiqin Han Xuebao He Fangfang Kuang Feng Zhao Peng Xiang Kuidong Xu Third Institute of Oceanography Ministry of Natural ResourcesXiamen 361005China Laboratory of Marine Organism Taxonomy and Phylogeny Chinese Academy of SciencesQingdao 266071China

The Clarion-Clipperton Zone(CCZ)hosts one of the largest known oceanic nodule fields worldwide and is regulated by the International Seabed Authority.A baseline assessment of diversity and distribution patterns is essential for reliable predictions of disturbed ecosystem response scenarios for sustained commercial activities in the future.In the present study,the spatial patterns and diversity of phytoplankton communities were analyzed along with upper ocean biogeochemistry,in the licensed China Ocean Mineral Resources R&D Association(COMRA)contract area and the surrounding western CCZ between August 21 and October 8,2017.Results indicated this was a typical low-nutrient low-chlorophyll a(Chl a)environment,characterized by low levels of phytoplankton abundance and diversity.In total 112 species belonging to 4 phyla were recorded(>10μm),with species counts including 82 diatoms,27 dinoflagellates,1 cyanobacteria and 2 chrysophyte.Dominant taxa in successive order of descending abundance and occurrence included Nizschia marina,Cyclotella stylorum,Dactyliosolen mediterraneus,Rhizosolenia setigera,Pseudo-nitzschia delicatissima,Thalassiothrix frauenfeldii,Synedra sp.,Chaetoceros simplex and Pseudo-nitzschia circumpora.The depth-averaged abundance and Chl a concentrations were(265±233)cells/L and(0.27±0.30)μg/L,respectively.Diatoms accounted for 90.94%of the community with(241±223)cells/L,while dinoflagellates accounted for 5.67%and(15±13)cells/L.The distribution pattern exhibited the same trend as abundance,Chl a and species richness,showing subsurface maximum levels at around 100 m,with stations near 10°N having higher levels than in the north.Cluster analysis was performed in two assemblages,relating to geographic locations to the south and north of 12°N.The subsurface maximum of abundance,Chl a,species richness,dissolved oxygen and nitrite were generally corresponding to the presence of high salinity North Pacific Central Water at depths of 50-120 m.Higher availability of nitrate,phosphate and silicic acid in the s

关键词： phytoplankton communities spatial patterns diversity upper ocean biogeochemistry Clarion-Clipperton Zone baseline assessment

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

spatial patterns of residents’ daily activity space and its influencing factors based on the CatBoost model: A case study of Nanjing, China

引用

Frontiers of Architectural Research 2022年第6期11卷 1193-1204页

作者： Jiemin Zheng Mingxing Hu Chenghui Wang Shuting Wang Bing Han Hui Wang School of Architecture Southeast UniversityNanjing210096China College of Landscape Architecture Nanjing Forestry UniversityNanjing210037China

The complexity and fragmentation of people’s activity space are challenging to planners.However,the relevant studies are mostly concerned on the relationship between the social attributes and the activity space of residents in a single or several communities,or the spatiotemporal laws of activity space on a macro scale.The research on the spatial characteristics of residents’activity space still needs to be strengthened.The present study analyses the spatial patterns of residents’activity space based on mobile phone signaling data to fill the gap of previous studies that assessed residents’activity space across small geographic areas.First,according to the spatial scope and direction of an activity space and residents’activity coverage rate,spatial patterns can be divided into three types:compact,extended,and directional extension patterns.The CatBoost method is then used to statistically analyze the influencing variables of spatial patterns,and the order of importance of the following influencing factors is determined:the built environment is more influential than social and economic situations.This study aims to strengthen the understanding of residents’activity space at the spatial level and provide a basis for the optimization of communities with different spatial patterns.

关键词： spatial patterns Activity space CatBoost Influencing factors Mobile phone signaling data

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Urbanization of county in China:spatial patterns and influencing factors

引用

Journal of Geographical Sciences 2022年第7期32卷 1241-1260页

作者： ZHANG Hua CHEN Mingxing LIANG Chen Beijing Key Laboratory of Environmental Remote Sensing and Digital Cities Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China Key Laboratory of Regional Sustainable Development Modeling Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China

This paper uses the fifth and sixth census data and 2018 demographic statistics to analyze the spatiotemporal evolution of the urbanization of county in China and the factors that influence the evolution.The paper reveals that the urbanization level of counties is a weak area in China’s overall urbanization.During the period from 2000 to 2010,the spatial patterns of the urbanization level of counties remained stable.Counties with high-level urbanization were concentrated in the coastal areas of the eastern region,while counties that experienced rapid urbanization were mainly located in the central and western regions.Regression analyses indicate that harsh natural endowments that constrain economic development are the most important factors that hinder the urbanization of county;these factors include marginalized locations far away from center cities,high altitudes,and a population with a low education level.This paper also compares two theoretical modes of new-type urbanization,nearby urbanization and remote urbanization,and argues that the new-type urbanization of county is the main form of nearby urbanization and provides an example of urbanization for developing countries worldwide.

关键词： new-type urbanization urbanization of county nearby urbanization spatial patterns influencing factors

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

spatial patterns and secular trends in human leishmaniasis incidence in Morocco between 2003 and 2013

引用

Infectious Diseases of Poverty 2016年第1期5卷 404-416页

作者： Mina Sadeq Environmental Epidemiology Unit National Institute of HygieneMinistry of Health27 Avenue Ibn BattutaBP 769 RabatMorocco

Background:Few studies on spatial patterns or secular trends in human leishmanias have been conducted in Morocco.This study aimed to examine spatial patterns and trends associated with the human leishmaniasis incidence rate(HLIR)at the province/prefecture level between 2003 and 2013 in Morocco.Methods:Only the available published country data on the HLIR between 2003 and 2013,from the open access files of the Ministry of Health,were used.Secular trends were examined using Kendall’s rank correlation.An exploratory spatial data analysis was also conducted to examine the spatial autocorrelation(Global Moran’s I and local indicator of spatial association[LISA]),and spatial diffusion at the province/prefecture level.The influence of various covariates(poverty rate,vulnerability rate,population density,and urbanization)on the HLIR was tested via spatial regression(ordinary least squares regression).Results:At the country level,no secular variation was observed.Poisson annual incidence rate estimates were 13 per 100000 population(95%CI=12.9–13.1)for cutaneous leishmaniasis(CL)and 0.4 per 100000 population(95%CI=0.4–0.5)for visceral leishmaniasis(VL).The available data on HLIR were based on combined CL and VL cases,however,as the CL cases totally outnumbered the VL ones,HLIR may be considered as CL incidence rate.At the provincial level,a secular increase in the incidence rate was observed in Al Hoceima(P=0.008),Taounate(P=0.04),Larache(P=0.002),Tétouan(P=0.0003),Khenifra(P=0.008),Meknes(P=0.03),and El Kelaa(P=0.0007),whereas a secular decrease was observed only in the Chichaoua province(P=0.006).Even though increased or decreased rate was evident in these provinces,none of them showed clustering of leishmaniasis incidence.Significant spatial clusters of high leishmaniasis incidence were located in the northeastern part of Morocco,while spatial clusters of low leishmaniasis incidence were seen in some northwestern and southern parts of Morocco;there was spatial randomness in the remaining parts of the country.Significant

关键词： Human leishmaniasis Epidemiology Incidence rates spatial patterns Secular trends Morocco

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

spatial patterns nitrogen transfer models of ectomycorrhizal networks in a Mongolian scotch pine plantation

引用

Journal of Forestry Research 2018年第2期29卷 337-344页

作者： Yanbin Liu Hongmei Chen Pu Mou College of Life Science Beijing Normal UniversityBeijing 100875People’s Republic of China Institute of Forestry Science Heilongjiang Academy of ForestryHarbin 150081People’s Republic of China Institute of Biology University of LeipzigJohannisallee 2104103 LeipzigGermany State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing 100875People’s Republic of China

Ectomycorrhizal(EM)networks provide a variety of services to plants and ecosystems include nutrient uptake and transfer,seedling survival,internal cycling of nutrients,plant competition,and so on.To deeply their structure and function in ecosystems,we investigated the spatial patterns and nitrogen(N)transfer of EM networks usingN labelling technique in a Mongolian scotch pine(Pinus sylvestris var.mongolica Litv.)plantation in Northeastern China.In August 2011,four plots(20 × 20 m)were set up in the plantation.125 ml 5 at.%0.15 mol/LNHNOsolution was injected into soil at the center of each plot.Before and 2,6,30 and 215 days after theN application,needles(current year)of each pine were sampled along four 12 m sampling lines.Needle total N andN concentrations were analyzed.We observed needle N andN concentrations increased significantly over time afterN application,up to 31 and0.42%,respectively.There was no correlation between needle N concentration andN/N ratio(R2=0.40,n=5,P=0.156),while excess needle N concentration and excess needleN/N ratio were positively correlated across different time intervals(R~2=0.89,n=4,P\0.05),but deceased with time interval lengthening.NeedleN/N ratio increased with time,but it was not correlated with distance.NeedleN/N ratio was negative with distance before and 6th day and 30th day,positive with distance at 2nd day,but the trend was considerably weaker,their slop were close to zero.These results demonstrated that EM networks were ubiquitous and uniformly distributed in the Mongolian scotch pine plantation and a random network.We found N transfer efficiency was very high,absorbed N by EM network was transferred as wide as possible,we observed N uptake of plant had strong bias forN andN,namely N fractionation.Understanding the structure and function of EM networks in ecosystems may lead to a deeper understanding of ecological stability and evolution,and thus provide new theoretical approaches to improve conservation practices for the management of the Earth’s ecosystems.

关键词： Ectomycorrhizal networks spatial patterns Nitrogen transfer Mongolian scotch pine plantation Stable isotope 15N labelling

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

spatial patterns of ecosystem vulnerability changes during 2001–2011 in the three-river source region of the Qinghai-Tibetan Plateau, China

引用

Journal of Arid Land 2016年第1期8卷 23-35页

作者： GUO Bing ZHOU Yi ZHU Jinfeng LIU Wenliang WANG Futao WANG Litao YAN Fuli WANG Feng YANG Guang LUO Wei JIANG Lin Institute of Remote Sensing and Digital Earth Chinese Academy of Sciences University of Chinese Academy of Sciences

The three-river source region (TRSR, including Yangtze, Yellow and Lancang rivers), located in the Qinghai-Tibetan Plateau, China, is a typical alpine zone with apparent ecosystem vulnerability and sensitivity. In this paper, we introduced many interdisciplinary factors, such as landscape pattern indices (Shannon diversity index and Shannon evenness index) and extreme climate factors (number of extreme high temperature days, number of extreme low temperature days, and number of extreme precipitation days), to establish a new model for evaluating the spatial patterns of ecosystem vulnerability changes in the TRSR. The change intensity (CI) of ecosystem vulnerability was also analyzed. The results showed that the established evaluation model was effective and the ecosystem vulnerability in the whole study area was intensive. During the study period of 2001–2011, there was a slight degradation in the eco-environmental quality. The Yellow River source region had the best eco-environmental quality, while the Yangtze River source region had the worst one. In addition, the zones dominated by deserts were the most severely deteriorated areas and the eco-environmental quality of the zones occupied by evergreen coniferous forests showed a better change. Furthermore, the larger the change rates of the climate factors (accumulative temperature of ≥10°C and annual average precipitation) are, the more intensive the CI of ecosystem vulnerability is. This study would provide a scientific basis for the eco-environmental protection and restoration in the TRSR.

关键词： eco-environmental vulnerability climate factors spatial patterns three-river source region

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

spatial patterns of Precipitation Anomalies for 30-yr Warm Periods in China During the Past 2000 Years

引用

Acta meteorologica Sinica 2012年第3期26卷 278-288页

作者：郝志新郑景云葛全胜张学珍 Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences

The spatial patterns of precipitation anomalies during five 30-yr warm periods of 691-720, 1231-1260, 1741-1770, 1921-1950, and 1981-2000 were investigated using a dryness/wetness grading dataset covering 48 stations from Chinese historical documents and 22 precipitation proxy series from natural archives. It was found that the North China Plain （approximately 35^-40~N, east of 105~E） was dry in four warm periods within the centennial warm epochs of 600-750, the Medieval Warm Period （about 900-1300） and after 1900. A wet condition prevailed over most of China during 1741-1770, a 30-yr warm peak that occurred during the Little Ice Age （about 1650-1850）. The spatial pattern of the precipitation anomaly in 1981-2000 over East China （25^-40~N, east of 105~E） is roughly consistent with that in 1231 1260, but a difference in the precipitation anomaly appeared over the Tibetan Plateau. The spatial patterns of the precipitation anomalies over China varied between all five 30-yr warm periods, which implies that the matching pattern between temperature and precipitation change is multiform, and the precipitation anomaly could be positive or negative when a decadal warm climate occurs in different climate epochs. This result may provide a primary reference for the mechanism detection and climate simulation of the precipitation anomaly of the future warm climate.

关键词： spatial patterns precipitation anomalies 30-yr warm periods past 2000 years China

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

spatial energy efficiency patterns and the coupling relationship with industrial structure： A study on Liaoning Province, China

引用

Journal of Geographical Sciences 2015年第3期25卷 355-368页

作者： GUAN Wei XU Shuting Research Center for Marine Economy and Sustainable Development Liaoning Normal University Dalian 116029 Liaoning China School of Urban and Environment Liaoning Normal University Dalian 116029 Liaoning China

Using a sample of 14 prefecture-level cities in Liaoning Province, this study first explored the spatial hierarchy and structural characteristics of energy efficiency from the following three viewpoints： energy technical efficiency based on data envelopment analysis, energy consumption per unit of GDP, and energy utilization efficiency combining the previous two indexes After measuring and analyzing the advancement, rationality, and concentration of the industrial structure in each city, we made some generalizations about the coupling features of the energy efficiency and industrial structure in Liaoning, using the coupling degree rating model Some of our conclusions are as follows：（1） The 14 cities differ significantly in their en- ergy efficiency, with Shenyang, Dalian, Anshan, and Jinzhou enjoying the highest energy effi- ciency. Northwestern Liaoning and other heavy-industrial cities such as Fushun and Benxi belong to low-efficiency and high-consumption areas. （2） In areas with higher efficiency, the spatial patterns of the energy technical efficiency, energy consumption per unit of GDP, and energy utilization efficiency are, respectively, ＂π ＂-, ＂Ⅱ＂- and ＂H＂- shaped. Geographically, the energy utilization efficiency shows different trends from east to west and from north to south. Factors such as the binuclear structure of economic development have a major effect on this spatial pattern of energy efficiency. （3） Southeastern Liaoning enjoys a highly advanced in- dustrial structure. Areas with a highly rational industrial structure form an ＂H＂ shape, with Shenyang and Dalian at the two poles. The urban agglomerations in middle and southern Liaoning have a highly concentrated industrial structure. （4） Overall, the coupling between energy efficiency and industrial structure is low in Liaoning, except for Shenyang and Dalian at both ends, where the coupling between an advanced industrial structure and energy efficiency is higher than in other cities.

关键词： energy efficiency industrial structure spatial patterns coupling

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

spatial distribution patterns of Symplocos congeners in a subtropical evergreen broad-leaf forest of southern China

引用

Journal of Forestry Research 2018年第3期29卷 765-776页

作者： Xiuqing Yang Haibing Yan Buhang Li Youzhi Han Bo Song College of Forestry Shanxi Agricultural University SYSU-Alberta Joint Lab for Biodiversity Conservation State Key Laboratory of Biocontrol School of Life Sciences Sun Yat-sen University Belle W. Baruch Institute of Coastal Ecology and Forest Science Clemson University

Studies on spatial distribution of congeneric species can supplement our understanding of species ecological processes. We analyzed population structure, spatial distribution, intra-and interspecific associations among six Symplocos tree species on a large(50 ha) plot in a subtropical, evergreen broad-leaf forest in southern China using spatial point pattern analysis methods. Our results suggested that the six Symplocos tree species were all clustered at small scales. The aggregation intensity of S. wikstroemiifolia with low abundance but relatively numerous large-diameter trees was much higher than that of the other five Symplocos species that occurred at high abundance but included few large-diameter trees. spatial associations among the six congeners showed that 12 of 30 pairs were associated positively at small scales, and 13 of 30 pairs were unrelated. For species among different size classes, 79 of 120 pairs were not correlated, and 17 of 120 pairs were associated positively. These results showed insufficient evidence for interspecific competition and congeneric Symplocos species commonly coexist within subtropical plant communities. The spatial patterns of Symplocos species and their correlations changed with size(DBH) class and were simultaneously affected by spatial scales; the intensity of their aggregation and association decreased with increasing area of the sample plot.

关键词： Population structure spatial patterns spatial associations Symplocos

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：