检索结果-南通市图书馆

Selective logging enhances ecosystem multifunctionality via increase of functional diversity in a Pinus yunnanensis forest in Southwest China

引用

Forest Ecosystems 2020年第4期7卷 733-745页

作者： Xiaobo Huang shuaifeng li Jianrong Su Research Institute of Resources Insects Chinese Academy of ForestryKunming 650224China Pu’er Forest Ecosystem Research Station National Forestry and Grassland AdministrationKunming 650224China

Background:The impacts of selective logging on ecosystem multifunctionality(EMF)remain largely *** this study,we analyzed the response of nine variables related to four ecosystem functions(*** cycling,soil carbon stocks,decomposition,and wood production)to five selective logging intensities in a Pinus yunnanensisdominated *** included a control group with no harvest to evaluate the potential shifts in EMF of the *** *** also assessed the relationship between above-and belowground biodiversity and EMF under these different selective logging ***,we evaluated the effects of biotic and abiotic factors on EMF using a structural equation modeling(SEM)***:Individual ecosystem functions(EFs)all had a significant positive correlation with selective logging *** EFs showed different patterns with the increase of selective logging *** found that EMF tended to increase with logging intensity,and that EMF significantly improved when the stand was harvested at least *** functional diversity and soil moisture had a significant positive correlation with EMF,but soil fungal operational taxonomic units(OTUs)had a significant negative correlation with *** on SEM,we found that selective logging improved EMF mainly by increasing functional ***:Our study demonstrates that selective logging is a good management technique from an EMF perspective,and thus provide us with potential guidelines to improve forest management in *** forests in this *** functional diversity is maximized through reasonable selective logging measures,so as to enhance EMF.

关键词： Biodiversity Ecosystem multifunctionality Functional traits Pinus yunnanensis Soil enzymatic activity Structural equation modeling

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

Species richness, forest types and regeneration of Schima in the subtropical forest ecosystem of Yunnan, southwestern China

引用

Forest Ecosystems 2020年第3期7卷 443-461页

作者： Cindy QTang Peng-Bin Han shuaifeng li li-Qin Shen Diao-Shun Huang Yun-Fang li Ming-Chun Peng Chong-Yun Wang Xiao-Shuang li Wei li Wei Wang Zhi-Ying Zhang Institute of Ecology and Geobotany College of Ecology and Environmental ScienceYunnan UniversityKunming650504China Research Institute on Resource Insects Chinese Academy of ForestryKunming650224China Caojian Forest Farm of Yunlong Forestry Bureau Yunlong County672711YunnanChina Yunnan Academy of Forestry Kunming650201China Tibet Agriculture and Animal Husbandry College Linzhi860000China

Background: Schima genus of Theaceae is confined to subtropics and tropics of South, East and Southeast *** species of Schima are distributed in subtropical China. Many of them appear as dominant canopy species in the subtropical forests. To date, Schima species richness distribution patterns of China have remained ***, there has been a longtime debate as to whether forests dominated by Schima species are early or late successional forests. We aim to clarify Schima species richness patterns and these species' roles in the forest succession and regeneration dynamics of the subtropical ecosystem in Yunnan Province, ***: We mapped Schima species richness distribution patterns in China. Based on 71 vegetation plots, we analyzed forest characteristics, population structure, and regeneration dynamics of Schima species in ***: Yunnan was found to harbor the greatest richness and the highest rarity-weighted richness of Schima species in the subtropical regions of China. We classified five primary and six secondary forest types containing Schima species as one of dominants. Yunnan had the high floristic diversity and varying stand structure of forests containing Schima species. The Schima species studied generally had a sporadic regeneration type and a long lifespan. Four species(Schima argentea, Schima villosa, Schima sinensis, Schima sericans) were shade-intolerant. But three species(Schima noronhae, Schima khasiana and Schima wallichii) were considered as bi-modal type species having shade-intolerant and shade-tolerant traits. Schima noronhae was seen to be a top dominant in late successional forests, while S. wallichii was found as a top-dominant in early or middle or late successional forests. ***, Schima villosa, Schima sinensis usually appeared as a top dominant in early or middle successional secondary forests, though they also presented as a second dominant in late-successional forests. Schima argentea and Schima se

关键词： Forest structure Regeneration dynamics Schima Species richness Forest succession Yunnan

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

Forest characteristics,population structure and growth trends of threatened relict Pseudotsuga forrestii in China

引用

Plant Diversity 2023年第4期45卷 422-433页

作者： Cindy Q.Tang Shi-Qian Yao Peng-Bin Han Jian-Ran Wen shuaifeng li Ming-Chun Peng Chong-Yun Wang Tetsuya Matsui Yong-Ping li Shan Lu Yuan He Institute of Ecology and Geobotany College of Ecology and Environmental ScienceYunnan UniversityBuilding ShixunChenggong CampusDongwaihuan South RoadUniversity TownChenggong New DistrictKunmingYunnan 650504China College of life Sciences Yunnan UniversityShengming Kexueyuan Building#2Chenggong CampusDongwaihuan South RoadUniversity TownChenggong New DistrictKunmingYunnan 650504China Institute of Highland Forest Science Chinese Academy of ForestryKunmingYunnan 650224China Forestry and Forest Products Research Institute Forest Research and Management OrganizationMatsunosato 1Tsukuba-shiIbaraki-ken305-8687Japan Faculty of life&Environmental Sciences University of Tsukuba1-1-1 TennodaiTsukubaIbaraki305-8572Japan College of Natural Resources Yunnan UniversityChenggong CampusDongwaihuan South RoadUniversity TownChenggong New DistrictKunmingYunnan 650504China Forestry and Grassland Bureau of Diqing Tibetan Autonomous Prefecture 1st Floor of Government BuildingShengping TownDeqing CountyYunnan 674500China Forestry and Grassland Bureau of Weixi lisu Autonomous County Nanjian Dao#7Baohe TownWeixi Lisu Autonomous CountyYunnan 674600China

Pseudotsuga forrestii is a relict evergreen coniferous tree species in Pinaceae endemic to *** tree numbers have greatly decreased due to deforestation,over-utilization and habitat *** we clarify *** community types,structure,species diversity,seedling recruitments and growth *** identified four *** community types:(1)Pseudotsuga forrestii-Quercus guyavifolia-Acer davidii evergreen coniferous and broad-leaved mixed forest;(2)Pseudotsuga forrestii-Pinus yunnanensis-Quercus guyavifolia evergreen coniferous and broad-leaved mixed forest;(3)Pseudotsuga forrestii evergreen coniferous forest;(4)Pseudotsuga forrestii-Abies georgei *** evergreen coniferous *** forests are characterized by both warm temperate and temperate *** diversity,Pielou evenness,Shannon-Wiener diversity indices ranged from 0.75 to 0.76,0.74-0.81,and 1.62-1.93,respectively,with no significant differences among the four forest *** forest stratification was *** canopy layer was generally 10-25 m tall,with the emergent layer reached 25-42 *** and age structures of *** showed multimodal *** maximum age *** was 570 years with a DBH of 143 *** growth of annual ring width of *** was slow,and generally decreased with age,whereas the basal area at the breast height increased with *** seedlings/saplings were mainly found in unstable *** of *** depends on moderate natural ***,we provide recommendations for *** conservation.

关键词： Pseudotsuga forrestii Community structure Species diversity Population structure Regeneration Growth trend

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

中国民营上市公司政治关联与审计收费关系

引用

同济大学学报（自然科学版） 2017年第3期45卷 447-452页

作者：李率锋郑少东同济大学经济与管理学院上海200092 同济大学审计处上海200092 上海行政学院第三分院上海200233

在分析中国资本市场股票发行审核制度改革基础上,以2008-2012年期间首次公开募股(简称IPO)民营公司为样本,对政治关联、审计收费及其相关的审计市场占有率三者的关系进行了实证研究.研究结果表明,在股票发行审核制度改革后,拥有发行审... 详细信息

在分析中国资本市场股票发行审核制度改革基础上,以2008-2012年期间首次公开募股(简称IPO)民营公司为样本,对政治关联、审计收费及其相关的审计市场占有率三者的关系进行了实证研究.研究结果表明,在股票发行审核制度改革后,拥有发行审核委员的会计师事务所不仅对拟IPO的民营公司收取了超额审计费,而且其审计市场占有率也显著提高;但是,若拟IPO的民营公司具有政治关联,则可以降低会计师事务所的审计收费.

关键词：政治关联审计收费市场占有率

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

Forest characteristics and population structure of a threatened palm tree Caryota obtusa in the karst forest ecosystem of Yunnan,China

引用

Journal of Plant Ecology 2022年第4期15卷 829-843页

作者： Cindy Q.Tang Xia Lu Min-Rui Du Shu-li Xiao shuaifeng li Peng-Bin Han Jia-Le Zeng Jian-Ran Wen Shi-Qian Yao You-Cai Shi Yun-Fang li Ming-Chun Peng Chong-Yun Wang Zhi-Ying Zhang Institute of Ecology and Geobotany College of Ecology and Environmental ScienceYunnan UniversityKunming 650504China Research Institute on Resource Insects Chinese Academy of ForestryKunming 650224China Management Office of Yunlong Tianchi National Nature Reserve GuolangDali PrefectureYunnan 672700China

Caryota obtusa of Arecaceae is a fascinating palm tree native to southwestern China,India,Myanmar,Thailand,Laos and *** is an economically important and threatened species and appears as a canopy dominant in some karst areas in *** aim to clarify the forest structure,species diversity,population status and regeneration dynamics of *** in the karst forest ecosystem of Yunnan,*** established 56 vegetation plots dominated by *** in 10 counties of southern *** on the plot data,we analyzed the community stratification,floristic composition and ***’s population *** used questionnaires to interview local people and recorded the human activity history in ***-dominated *** obtusa palm forests were distributed on limestone mountain slopes and *** were seven forest community *** stratification of each community included arborous layer,shrub layer and *** communities had rich species *** all the plots as a whole of each community type,Shannon–Wiener diversity index of either woody or herbaceous species ranged from 2.1 to *** diameter at breast height(DBH)-class frequency distribution of *** was a multimodal *** regeneration was sporadic and dependent on intermediate natural *** the current population structure,a number of *** trees with small DBHs consisted mainly of the forest communities with no or a slight degree of human *** human activities terribly hindered recruitment of ***,followed by the medium intensity of human activities.

关键词： Caryota obtusa community structure species diversity population structure regeneration dynamics human disturbance

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

Forest characteristics and population structure of Glyptostrobus pensilis, a globally endangered relict species of southeastern China

引用

Plant Diversity 2019年第4期41卷 237-249页

作者： Cindy Q. Tang Yongchuan Yang Arata Momohara Huan-Chong Wang Hong Truong Luu shuaifeng li Kun Song Shenhua Qian Ben LePage Yi-Fei Dong Peng-Bin Han Masahiko Ohsawa Buu Thach Le Huu Dang Tran Minh Tri Dang Ming-Chun Peng Chong-Yun Wang Institute of Ecology and Geobotany School of Ecology and Environmental ScienceYunnan UniversityDongwaihuan South RoadUniversity TownChenggong New DistrictKunmingYunnan 650504China The Nature Conservancy Society of Japan Mitoyo Bldg.2F1-16-10 ShinkawaChuo-kuTokyo 104-0033Japan Key Laboratory of Three Gorges Reservoir Region's Eco-Environment Ministry of EducationChongqing UniversityChongqing 400045China Graduate School of Horticulture Chiba University648 MatsudoChiba 271-8510Japan Institute of Botany Yunnan UniversityKunmingYunnan 650091China Southern Institute of Ecology Vietnam Academy o f Science and TechnologyHo Chi Minh CityViet Nam Research Institute of Resource Insects Chinese Academy of ForestryKunmingYunnan 650224China School o f Ecological and Environmental Sciences East China Normal UniversityShanghai 200241China Pacific Gas and Electric Company 3401 Crow Canyon RoadSan RamonCA 94583USA The Academy of Natural Science 1900 Benjamin Franklin ParkwayPhiladelphiaPA 19W3USA

The Chinese water pine Glyptostrobus pensilis is the sole surviving species of the genus Glyptostrobus. It is endemic to southern China, central Vietnam, and eastern Laos, and today it is nearly extinct in the wild. Forest community characteristics and population structure of G. pensilis in China have remained un-known up to now. We investigated six swamp forest stands and analyzed their forest community characteristics (i.e. vertical stratification, species composition, and diversity) and population structure, including the frequency distribution of DBH (diameter at breast height) and age-classes as found in Fujian Province, southeastern China. The vertical stratifications of all the forest stands were rather simple. The remaining wild specimens ranged from roughly 15 to some 357 years for an average of ca. 85 years, with only a few individuals less than 20 years old. Compared with the stands and populations of G. pensilis in Vietnam, the taxonomic compositions of the stands in the two regions were different, except for the dominant species-G. pensilis. The Shannon-Wiener index showed the overstory of each stand had much lower diversity (0.26 on average) in Fujian Province than that (1.97 on average) in Vietnam, whereas the diversity indices were about the same (around 2.41) for the understories in the two regions. Furthermore, we discovered 18 G. pensilis seedlings at the study sites in Fujian Province. This discovery demonstrates that G. pensilis regeneration is extremely poor and its populations are declining, although these populations are rela-tively healthier than those in Vietnam.

关键词： Age-class Fujian Province Glyptostrobus Regeneration Relict plant Vietnam

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

云南红豆杉的保护和开发利用

引用

应用与环境生物学报 2021年第3期27卷 705-715页

作者：唐荣李帅锋苏建荣中国林业科学研究院资源昆虫研究所昆明650224

云南红豆杉(Taxus yunnanensis ***&***)是红豆杉属植物中紫杉醇含量最高的树种,同时也是我国红豆杉属中分布最广和资源蕴藏量最丰富的物种.然而,近年来由于人为大量砍伐,云南红豆杉野生资源遭到严重破坏,加上生长缓慢且天然更新困难,... 详细信息

云南红豆杉(Taxus yunnanensis ***&***)是红豆杉属植物中紫杉醇含量最高的树种,同时也是我国红豆杉属中分布最广和资源蕴藏量最丰富的物种.然而,近年来由于人为大量砍伐,云南红豆杉野生资源遭到严重破坏,加上生长缓慢且天然更新困难,目前处于濒危状态.对云南红豆杉天然资源的保护和药用人工林的培育对于云南红豆杉资源的可持续利用具有重要的意义.对云南红豆杉资源分布现状及种群和繁殖生态学等方面的研究进行综述,发现云南红豆杉的濒危是由其自身繁殖机制引起的天然更新困难、对环境的适应能力较低以及人为因素共同导致的.同时从紫杉醇含量的影响因素及获取方式、人工药用林培育方面总结了云南红豆杉的开发利用现状,发现云南红豆杉中紫杉醇的含量受其自身特性及外在因素的综合影响;包含紫杉醇在内的紫杉烷类物质目前主要通过直接提取和半合成两种方式获取;此外在全合成、组织或细胞培养及真菌诱导等方式上也有了新的研究进展.最后,建议从就地保护、迁地保护及引种回归3个方面对云南红豆杉天然资源进行综合保护,同时大力推进紫杉烷工业化合成方式的研究和云南红豆杉人工药用原料林的培育,提高云南红豆杉的资源利用效率,在保护云南红豆杉天然林的同时实现资源的合理利用.

关键词：云南红豆杉紫杉醇 10-DAB 濒危植物保护人工药用原料林开发利用

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

翼型风帆液压系统的设计与分析

引用

机床与液压 2019年第9期47卷 125-128页

作者：牛春立李帅锋大连经济技术开发区中等职业技术专业学校辽宁大连116622 哈尔滨工业大学黑龙江哈尔滨150090

主要介绍翼型风帆液压系统的组成、控制原理,设计特点和试验试航等内容。通过陆基试验,船载试航完成各工况海况加载及数据采集分析,证明整机已达到设计要求。该液压系统的成功研发使用,对翼型风帆的推广使用和节能降耗有着重要意义。

关键词：风帆升降风帆旋转电液比例控制节能降耗减排

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

自适应进化模型下的土壤重金属含量预测

引用

湖南农业大学学报（自然科学版） 2024年第2期50卷 120-126页

作者：李亮亮张聪曹坤黎帅锋武汉轻工大学数学与计算机学院湖北武汉430023 武汉轻工大学电气与电子工程学院湖北武汉430023 汉口学院计算机科学与技术学院湖北武汉430212

针对Elman神经网络在土壤重金属含量预测时出现预测精度低、模型收敛速度慢等问题,提出一种自适应进化模型(AEM)。该模型以Elman神经网络为基础,运用贝叶斯正则化优化Elman神经网络的目标函数,提高网络模型预测精度;为解决网络模型收敛... 详细信息

针对Elman神经网络在土壤重金属含量预测时出现预测精度低、模型收敛速度慢等问题,提出一种自适应进化模型(AEM)。该模型以Elman神经网络为基础,运用贝叶斯正则化优化Elman神经网络的目标函数,提高网络模型预测精度;为解决网络模型收敛速度慢和易陷入局部极值等缺陷,采用自适应灰狼算法(AGWA)对网络模型初始参数进行优化;采用基于熵权距离的离群点检测法剔除数据中的离群点,以降低离群点对预测结果的干扰。以武汉市农业科学院采集的农田土壤重金属含量数据进行预测试验,AEM模型预测重金属含量的平均绝对误差和平均绝对百分比误差分别为1.623和17.48%,其决定系数比Elman的提高了0.394。AEM、自调整反距离加权插值模型(SIDIM)、小波神经网络模型(CBSA-WNN)、双向门控循环神经网络模型(SBGRNN)及Elman神经网络模型等5种不同预测模型进行对比试验表明,AEM模型在土壤重金属含量预测上具有更高的准确性。消融试验结果表明,贝叶斯正则化优化、自适应灰狼算法优化和基于熵权距离的离群点检测的离群点数据剔除等3个改进点对于提升土壤重金属含量预测精度均有一定的贡献。

关键词：土壤重金属自适应进化模型灰狼算法 Elman神经网络数据预测

来源：

维普期刊数据库博看期刊

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

罗平城市绿地树种多样性与生态系统多功能性的关系

引用

西南林业大学学报（自然科学） 2023年第1期43卷 186-193页

作者：李晓红彭建松李帅锋西南林业大学园林园艺学院云南昆明650233 西南林业大学森林城市研究院云南昆明650233 中国林业科学研究院资源昆虫研究所云南昆明650233

基于云南罗平县45个样地的调查数据,选取绿量、降温、增湿、降噪4个生态系统功能变量,采用平均值法分析城市绿地树种多样性和生态系统多功能性的关系。结果表明:罗平县城市不同绿地中树种多样性综合指数(K)从高到低排序为公园绿地(1.76)... 详细信息

基于云南罗平县45个样地的调查数据,选取绿量、降温、增湿、降噪4个生态系统功能变量,采用平均值法分析城市绿地树种多样性和生态系统多功能性的关系。结果表明:罗平县城市不同绿地中树种多样性综合指数(K)从高到低排序为公园绿地(1.76)>街旁绿地(1.68)>居住区绿地(1.64)>单位绿地(1.59)>校园绿地(1.33)。树种丰富度指数(G)与绿量、增湿、降温显著正相关,对降噪影响不显著;Simpson指数(D)和Shannon-Wiener指数(H)对绿量、降温、增湿和降噪存在显著的正相关关系;均匀度指数(J)与绿量、降噪和增湿显著正相关,与降温无显著相关关系。城市绿地树种多样性与生态系统多功能性间呈极显著的正相关关系,且Shannon-Wiener指数对多功能性的影响最大(R^(2)=0.694,P<0.01),说明同时维持多种生态功能需要更丰富的植株总量和物种数量来支撑。城市绿地树种多样性对生态系统功能具有重要意义,与单一功能相比,对多功能性的影响力更大。

关键词：树种多样性生态系统多功能性城市绿地罗平

来源：

维普期刊数据库博看期刊

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：