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黄土区不同施肥条件下农田土壤的动物群落结构 被引量:5
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作者 林英华 张夫道 +3 位作者 杨学云 古巧珍 孙本华 马路军 《植物营养与肥料学报》 CAS CSCD 北大核心 2003年第4期484-488,共5页
利用手捡法和Cobb过筛法对国家黄土土壤肥力与肥料效益监测基地的13个不同施肥处理进行土壤动物调查,共获得土壤动物3530只,隶属6门12纲23目4亚目7总科,这些类群在黄土中分布较广,构成了陕西黄土农田土壤动物的主要成分。结果表明,1)不... 利用手捡法和Cobb过筛法对国家黄土土壤肥力与肥料效益监测基地的13个不同施肥处理进行土壤动物调查,共获得土壤动物3530只,隶属6门12纲23目4亚目7总科,这些类群在黄土中分布较广,构成了陕西黄土农田土壤动物的主要成分。结果表明,1)不同施肥处理对农田土壤动物个体数量、类群数均有不同程度的影响;农田土壤动物个体数量主要集中在0~5cm,且基本上是随着土壤深度的增加呈现下降的趋势。2)农田土壤动物的密度与土壤中的有机质含量有一定关系,施用秸秆有利于农田土壤动物的生存和发展。3)不同施肥条件下,土壤动物群落的组成具有很高的异质性,相似性系数一般较低。 展开更多
关键词 黄土区 施肥条件 农田土壤 动物 群落结构 手捡法 Cobb过筛法 个体 类群数 异质性
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农田边界生物多样性与边界属性相互关系研究 被引量:19
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作者 谷卫彬 宇振荣 刘因慧 《生态学杂志》 CAS CSCD 北大核心 2002年第3期10-14,共5页
Biological community including carabids and spiders were investigated in 30 various fields margins and 10 related fields by pitfall trap in Quzhou area of North China Plain.It was concluded that biodiversity index and... Biological community including carabids and spiders were investigated in 30 various fields margins and 10 related fields by pitfall trap in Quzhou area of North China Plain.It was concluded that biodiversity index and numbers of biological groups in field margins are higher than those in the related crop fields.There is a given relationship between the attributes of field margins and biodiversity.The control of structure and vegetation in field margins would be the possible way to protect natural enemy such as carabides and spiders. 展开更多
关键词 农田边界 生物多样性 边界属性 相互关系 生物类群数
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千佛山地区土壤动物群落结构的研究 被引量:3
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作者 傅荣恕 肖锋 李常月 《山东林业科技》 北大核心 1992年第S1期76-79,共4页
对千佛山地区阳面荒坡、阳坡柏林、阴坡柏林和阴面荒坡4种生境的土壤动物群落的调查结果表明:螨类、弹尾类、膜翅类为千佛山地区土壤动物群落的优势类群;多样性、均匀性、优势度指数表明,人类活动影响土壤动物的数量分布;不同群落间相... 对千佛山地区阳面荒坡、阳坡柏林、阴坡柏林和阴面荒坡4种生境的土壤动物群落的调查结果表明:螨类、弹尾类、膜翅类为千佛山地区土壤动物群落的优势类群;多样性、均匀性、优势度指数表明,人类活动影响土壤动物的数量分布;不同群落间相似程度较大,说明千佛山地区环境条件差异不显著。 展开更多
关键词 土壤动物群落 佛山地区 群落结构 优势度指 类群数 常见类群 动物类群 量分布 优势类群 森林凋落物
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土壤动物的多样性及对生态环境系统的意义 被引量:2
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作者 韩冬 《河南科技》 2011年第2X期17-17,共1页
近年来随着地下生态学的崛起,土壤动物的相关研究引起更大的关注。目前,土壤动物生态学的研究不论从学科的发展、资料的积累、过程研究和实际应用等方面,都有了长足的进展。主要涉及土壤动物区系组成、多样性和生态分布及其与环境因子... 近年来随着地下生态学的崛起,土壤动物的相关研究引起更大的关注。目前,土壤动物生态学的研究不论从学科的发展、资料的积累、过程研究和实际应用等方面,都有了长足的进展。主要涉及土壤动物区系组成、多样性和生态分布及其与环境因子之间的关系,土壤动物在生态系统物质循环中的作用及土壤动物与微生物、植物及草食动物的关系等。 展开更多
关键词 土壤动物 动物生态学 生态环境系统 生态分布 环境因子 动物类群 生态系统物质 土壤线虫 类群数 个体密度
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The Classification of Positive Definite Unimodular Lattices Over Z[(1+21^(1/2))/2]
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作者 王瑞卿 《Chinese Quarterly Journal of Mathematics》 CSCD 2000年第2期87-93,共7页
In this paper, the author applies adjacent lattice method and Siegel mass formula to determine the classes of positive definite unimodular lattices of rank 4 over Z , and obtains that the class number of unit genus ... In this paper, the author applies adjacent lattice method and Siegel mass formula to determine the classes of positive definite unimodular lattices of rank 4 over Z , and obtains that the class number of unit genus gen( I 4 ) is nine and the class number of even unimodular lattices is three, and also gives the representative lattices of each class. 展开更多
关键词 positive definite unimodular adjacent lattice class number Siegel mass formula orthogonal group
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The Classification of Positive Definite Unimodular Lattices Over Z[(1+211/2)/2] 被引量:4
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作者 王瑞卿 《Chinese Quarterly Journal of Mathematics》 CSCD 2000年第2期87-93,共页
In this paper, the author applies adjacent lattice method and Siegel mass formula to determine the classes of positive definite unimodular lattices of rank 4 over Z , and obtains that the class number of unit genus ... In this paper, the author applies adjacent lattice method and Siegel mass formula to determine the classes of positive definite unimodular lattices of rank 4 over Z , and obtains that the class number of unit genus gen( I 4 ) is nine and the class number of even unimodular lattices is three, and also gives the representative lattices of each class. 展开更多
关键词 positive definite unimodular adjacent lattice class number Siegel mass formula orthogonal group
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Status and distribution changes of the endangered Green Peafowl (Pavo muticus) in China over the past three decades (1990s-2017) 被引量:13
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作者 Dejun Kong Fei Wu +4 位作者 Pengfei Shan Jianyun Gao Dao Yan Weixiong Luo Xiaojun Yang 《Avian Research》 CSCD 2018年第2期102-110,共9页
Background: Understanding the changes in population dynamics, including demographics, distribution and threats is essential for species status assessing.The endangered Green Peafowl (Povo muticus) has experienced s... Background: Understanding the changes in population dynamics, including demographics, distribution and threats is essential for species status assessing.The endangered Green Peafowl (Povo muticus) has experienced sharp population declines and d stribution range diminishing both in China and Southeast Asia. Field population surveys have not been conducted in China since the 1990s, which hindered conservation planning and decision-making.Methods: With interview and line transects methods, we figured out the population and distribution changes of Green Peafowl across its historical ranges over the past three decades in China during 2014-2017.Results: The Green Peafowl once habituated in 54 counties in China. Nearly 60% of the distribution counties were lost in the past three decades, with the left 22 counties distributed in central, southern and western Yunnan, SW China. Population decrease detected in all distribution areas except for Shuangbai and Xinping county where more than 60% of the total population is located. Only about 30% of the former bird population were recorded with the same interviewing method as 20 years ago.Three birds, 1 carcass, 6 calls and 12 footprints were detected along the 865 km line transects, indicating extremely low encounter rate of Green Peafowl in field. Sharp decreases in flock sizes were also detected, from 8-20 birds per flock in the 1990s to 3-5 birds at present. Poaching and habitat conversion are two widespread and long-lasting threats, while poison tion affect regional population's survival. Large flocks of 18 ng caused mortality in the past and hydropower construc -27 birds were discovered in the field, which increases our confidence of population recovery of this endangered pheasant in China.Conclusions: Only interviewed bird number and counts based on line transects were presented in this study, without further population estimation due to limitation of the data sets. Although the actual population of this cryptic bird must be underestimated, dramatic population declines and distribution concentrations of the endangered Green Peafowl occurred over the past 30 years in China undoubtedly. 展开更多
关键词 Green Peafowl Population decline Range concentration Endangered species Southwestern China
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Status and historical changes in the fish community in Erhai Lake 被引量:7
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作者 唐剑锋 叶少文 +5 位作者 李为 刘家寿 张堂林 郭志强 朱峰跃 李钟杰 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2013年第4期712-723,共12页
Erhai Lake is the second largest freshwater lake on the Yunnan Plateau, Southwest China. In recent decades, a number of exotic fish species have been introduced into the lake and the fish community has changed conside... Erhai Lake is the second largest freshwater lake on the Yunnan Plateau, Southwest China. In recent decades, a number of exotic fish species have been introduced into the lake and the fish community has changed considerably. We evaluated the status of the fish community based on surveys with multimesh gillnet, trap net, and benthic fyke-net between May 2009 and April 2012. In addition, we evaluated the change in the community using historical data (1952-2010) describing the fish community and fishery harvest. The current fish community is dominated by small-sized fishes, including Pseudorasbora parva, Rhinogobius giurinus, Micropercops swinhonis, Hemiculter leucisculus, and Rhinogobius cliffordpopei. These accounted for 87.7% of the 22 546 total specimens collected. Omnivorous and carnivorous species dominated the community. A canonical correspondence analysis (CCA) plot revealed that the distribution of fishes in the lake is influenced by aquatic plants, water temperature, pH, and season. The abundance of indigenous species has declined sharply, and a majority of endemic species have been extirpated from the lake (a decrease from seven to two species). In contrast, the number of exotic species has increased since the 1960s to a total of 22 at present. The fishery harvest decreased initially following the 1960s, but has since increased due to the introduction of non-native fish and stocking of native fish. The fishery harvest was significantly correlated with total nitrogen, not total phosphorus, during the past 20 years. Based on our results, we discuss recommendations for the restoration and conservation of the fish resources in Erhai Lake. 展开更多
关键词 Erhai Lake fish community small fishes indigenous fish species exotic fish species
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Lie Group Classifications and Non-differentiable Solutions for Time-Fractional Burgers Equation 被引量:1
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作者 吴国成 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第6期1073-1076,共4页
Lie group method provides an efficient tool to solve nonlinear partial differential equations. This paper suggests Lie group method for fractional partial differential equations. A time-fractional Burgers equation is ... Lie group method provides an efficient tool to solve nonlinear partial differential equations. This paper suggests Lie group method for fractional partial differential equations. A time-fractional Burgers equation is used as an example to illustrate the effectiveness of the Lie group method and some classes of exact solutions are obtained. 展开更多
关键词 Lie group method fractional Burgers equation fractional characteristic method
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A new-style clustering algorithm based on swarm intelligent theory
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作者 陈卓 刘相双 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2007年第1期69-73,共5页
Traditional clustering algorithms generally have some problems, such as the sensitivity to initializing parameter, difficulty in finding out the optimization clustering result and the validity of clustering. In this p... Traditional clustering algorithms generally have some problems, such as the sensitivity to initializing parameter, difficulty in finding out the optimization clustering result and the validity of clustering. In this paper, a FSM and a mathematic model of a new-style clustering algorithm based on the swarm intelligence are provided. In this algorithm, the clustering main body moves in a three-dimensional space and has the abilities of memory, communication, analysis, judgment and coordinating information. Experimental results conform that this algorithm has many merits such as insensitive to the order of the data, capable of dealing with exceptional, high-dimension or complicated data. The algorithm can be used in the fields of Web mining, incremental clustering. economic analysis, oattern recognition, document classification and so on. 展开更多
关键词 data mining swarm intelligence CLUSTERING Web mining incremental clustering
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Summertime community structure of intertidal macrobenthos in Changdao Archipelago,Shandong Province,China 被引量:6
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作者 王晓晨 李新正 +1 位作者 李宝泉 王洪法 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2009年第3期425-434,共10页
The community structure of intertidal macrobenthos in Changdao Archipelago(north of Shandong Peninsula,between Bohai Bay and the northern Yellow Sea) was examined based on samples collected from 14 stations in five tr... The community structure of intertidal macrobenthos in Changdao Archipelago(north of Shandong Peninsula,between Bohai Bay and the northern Yellow Sea) was examined based on samples collected from 14 stations in five transects in June 2007.Three stations corresponding to high,medium and low tidal areas were set up for each transect.A total of 68 macrobenthic species were found in the research region,most of which belonged to Mollusca and Crustacea.The average abundance and biomass of the macrobenthos was 1 383 ind./m2 and 372.41 g/m2,respectively.The use of an arbitrary similarity level of 20% resulted in identification of five groups among the 14 stations in the research region.There were remarkable differences in the biomass,abundance and Shannon-Wiener diversity index of the different sediments.Specifically,the order of biomass was rocky shores > gravel > mud-sand > coarse sand > stiff mud,while the order of abundance was rocky shores > coarse sand > mud-sand > gravel > stiff mud,and that of the diversity index was mud-sand > gravel > stiff mud > rocky shores > coarse sand.The above results revealed that the sediment type was the most important factor affecting the structure of the macrobenthic community of the intertidal zone. 展开更多
关键词 MACROBENTHOS community structure biodiversity Changdao Archipelago sediment
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Clustering Categorical Data:A Cluster Ensemble Approach
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作者 何增友 Xu +2 位作者 Xiaofei Deng Shengchun 《High Technology Letters》 EI CAS 2003年第4期8-12,共5页
Clustering categorical data, an integral part of data mining,has attracted much attention recently. In this paper, the authors formally define the categorical data clustering problem as an optimization problem from th... Clustering categorical data, an integral part of data mining,has attracted much attention recently. In this paper, the authors formally define the categorical data clustering problem as an optimization problem from the viewpoint of cluster ensemble, and apply cluster ensemble approach for clustering categorical data. Experimental results on real datasets show that better clustering accuracy can be obtained by comparing with existing categorical data clustering algorithms. 展开更多
关键词 CLUSTERING categorical data cluster ensemble data mining
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A New Descent Algebra for Weyl Groups of Type An
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作者 Tulay YAGMUR Himmet CAN 《Journal of Mathematics and System Science》 2016年第6期242-247,共6页
In this paper we define an equivalence relation on the set of all xj in order to form a basis for a new descent algebra of Weyl groups of type A,. By means of this, we construct a new commutative and semi-simple desce... In this paper we define an equivalence relation on the set of all xj in order to form a basis for a new descent algebra of Weyl groups of type A,. By means of this, we construct a new commutative and semi-simple descent algebra for Weyl groups of type An generated by equivalence classes arising from this equivalence relation. 展开更多
关键词 Weyl groups type An descent algebra.
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The calculation for C-G coefficients
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作者 王爱芬 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2006年第5期564-567,共4页
The eigenfunction method put forward by Chen Jin-quan is illustrated. We apply this theory to the space group D1_ 6h. The selection rules of this space are worked out in the points of higher symmetry A,K,H in the firs... The eigenfunction method put forward by Chen Jin-quan is illustrated. We apply this theory to the space group D1_ 6h. The selection rules of this space are worked out in the points of higher symmetry A,K,H in the first Brillion Zone. The C-G coefficients are calculated for K.HA. 展开更多
关键词 EIGENFUNCTION class operator class space representation group irreducible basis subgroup chain
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Clustering: from Clusters to Knowledge
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作者 Peter Grabusts 《Computer Technology and Application》 2013年第6期284-290,共7页
Data analysis and automatic processing is often interpreted as knowledge acquisition. In many cases it is necessary to somehow classify data or find regularities in them. Results obtained in the search of regularities... Data analysis and automatic processing is often interpreted as knowledge acquisition. In many cases it is necessary to somehow classify data or find regularities in them. Results obtained in the search of regularities in intelligent data analyzing applications are mostly represented with the help of IF-THEN rules. With the help of these rules the following tasks are solved: prediction, classification, pattern recognition and others. Using different approaches---clustering algorithms, neural network methods, fuzzy rule processing methods--we can extract rules that in an understandable language characterize the data. This allows interpreting the data, finding relationships in the data and extracting new rules that characterize them. Knowledge acquisition in this paper is defined as the process of extracting knowledge from numerical data in the form of rules. Extraction of rules in this context is based on clustering methods K-means and fuzzy C-means. With the assistance of K-means, clustering algorithm rules are derived from trained neural networks. Fuzzy C-means is used in fuzzy rule based design method. Rule extraction methodology is demonstrated in the Fisher's Iris flower data set samples. The effectiveness of the extracted rules is evaluated. Clustering and rule extraction methodology can be widely used in evaluating and analyzing various economic and financial processes. 展开更多
关键词 Data analysis clustering algorithms K-MEANS fuzzy C-means rule extraction.
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施氮肥对落叶松和水曲柳人工林土壤动物群落的影响 被引量:11
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作者 庄海峰 孙玥 +2 位作者 谷加存 许旸 王政权 《生物多样性》 CAS CSCD 北大核心 2010年第4期390-397,429-430,共8页
土壤动物对环境变化反应敏感,全球变化导致土壤氮(N)有效性增加将影响土壤动物群落结构和功能。本文以落叶松(Larix gmelinii)和水曲柳(Fraxinus mandshurica)人工林为研究对象,通过施肥处理,在不同季节和土层取样,研究土壤N有效性增加... 土壤动物对环境变化反应敏感,全球变化导致土壤氮(N)有效性增加将影响土壤动物群落结构和功能。本文以落叶松(Larix gmelinii)和水曲柳(Fraxinus mandshurica)人工林为研究对象,通过施肥处理,在不同季节和土层取样,研究土壤N有效性增加对土壤动物的数量、类群数和不同功能团的影响。结果表明:(1)施肥影响两林分土壤动物密度,导致当年密度增加,翌年则下降,这种先增加后降低的趋势在不同土层中均表现出来;(2)施肥增加了两林分土壤动物类群数,其中落叶松林分从34类增加到43类,水曲柳林分从43类增加到48类;(3)施肥改变了两林分不同食性土壤动物的密度,腐食性土壤动物数量降低、植食性数量增加、捕食性数量变化不明显。这些结果说明:土壤N有效性增加显著影响两林分土壤动物群落结构,可能改变地下碳分配格局和养分循环过程。 展开更多
关键词 施N肥 土壤动物密度 类群数 食性 土钻法
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《江苏植物志》修订再版,令人耳目一新 被引量:7
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作者 马克平 《生物多样性》 CAS CSCD 北大核心 2017年第8期914-914,共1页
《江苏植物志》上册和下册分别于1977年和1982年出版,时隔30年后得以修订再版,可喜可贺。总览新版《江苏植物志》1–5卷(2013–2015年出版,刘启新主编),令人耳目一新。第一,收载江苏省植物的类群数量和范围增加。与原《江苏植物志》相... 《江苏植物志》上册和下册分别于1977年和1982年出版,时隔30年后得以修订再版,可喜可贺。总览新版《江苏植物志》1–5卷(2013–2015年出版,刘启新主编),令人耳目一新。第一,收载江苏省植物的类群数量和范围增加。与原《江苏植物志》相比,修订版增加了苔藓植物;而且维管植物种数也增加了近1/3。 展开更多
关键词 植物志 类群数 植物种 维管 令人 《中国植物志》 凭证标本 出版发行 FLORA 分类学研究
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Weak Hopf Algebras and Regular Monoids 被引量:1
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作者 李方 《Journal of Mathematical Research and Exposition》 CSCD 1999年第2期325-331,共7页
Weak Hopf algebra is defined. The aim of this work is to study the relations between the weak antipode of a weak Hopf algelra and the monoid of group like elements. At first, the author shows some properties of weak ... Weak Hopf algebra is defined. The aim of this work is to study the relations between the weak antipode of a weak Hopf algelra and the monoid of group like elements. At first, the author shows some properties of weak Hopf algebras. And, for some weak Hopf algebras, some properties of the weak antipodes are given if the monoids of group like elements are inverse or orthodox semigroups. At end, the author gets a weak Hopf algebra whose monoid of group like elements is regular. 展开更多
关键词 weak Hopf algebra weak autipode group like element regular monoid.
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生物与土壤
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《中国地理与资源文摘》 2008年第2期34-34,共1页
关键词 高寒草甸 放牧强度 水土保持功能 grassland 嵩草 类群数 江河源 地上生物量 返青期 退化
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5A景区做实验
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作者 张迎迎 《大学生》 2016年第18期72-73,共2页
被外派到云南做实验后,我在组里认识了一位师姐,她是中国科学院动物所动物学博士生,研究方向是昆虫间的关系,常年的实验地是位于西双版纳的中国科学院热带植物园。中国科学院西双版纳热带植物园不仅是研究机构,也是我国面积最大、收集... 被外派到云南做实验后,我在组里认识了一位师姐,她是中国科学院动物所动物学博士生,研究方向是昆虫间的关系,常年的实验地是位于西双版纳的中国科学院热带植物园。中国科学院西双版纳热带植物园不仅是研究机构,也是我国面积最大、收集物种最丰富、植物专类园区最多的植物园,亦是世界上户外保存植物种数和向公众展示的植物类群数最多的植物园。在这样的5A级景区里做实验,师姐的体验自然也与众不同。 展开更多
关键词 类群数 植物种 榕小蜂 专类园 研究机构 聚果榕 中国科学院 互利共生 环刀 手脚并用
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