北京湿地维管植物区系研究

记录了分布于北京地区的典型湿地维管植物266种7变种1变型,共274个分类群,隶属于58科144属。从种一级的水平对这274个分类群进行分析,可分为14个分布区类型,其中温带性质的种187种,为整个区系成分的主体,另有世界广布种45种,热带性质的种30种,中国特有种12种。就北京湿地维管植物区系特征而言,其种类组成与华北其他地区湿地存在着相似性,温带成分占优势地位,并存在一些古老孑遗种类及特有种。此外,还对区系成分中的受危种和外来种进行了讨论。     

北京市奥林匹克森林公园植物组成分析

奥林匹克森林公园是目前北京市最大的城市公园,自建成以来,奥林匹克森林公园的植物种类组成与来源尚无报道。论文在实地调查数据的基础上,对北京市奥林匹克森林公园的植物组成与分布进行了研究,调查发现园内共有维管束植物295种,隶属于75科,203属,其中乔木种60种,灌木种57种,草本植物170种,藤本8种。按照植物种的自然分布情况统计,发现在园内295种维管束植物中,有北京地区乡土种179种,外来种116种,其中包括外来入侵种4种。按照植物种的来源统计,发现有人工栽种种183种,野生种112种。通过比较分析:发现公园内栽培的本地灌木种占全部栽培灌木种数比例(50.00%)高于整个北京市建成区的比例(27.00%);公园内物种多是国内引进。最后提出了丰富园内野生灌木植物种类;保持乡土种利用;减少对外来种使用等的建议。     

基于地理环境相似度的长江经济带入侵物种虚拟负样本生成方法

入侵物种空间分布建模的核心数据源来源于物种多样性采样(物种出现点和未出现点),然而,大多数入侵物种标本库只记录物种出现点样本信息,缺乏对未出现点(负样本)位置的记录。因此,生成有效的入侵物种虚拟负样本是建立物种空间分布模型的关键。本文提出了一种基于地理环境相似度的虚拟负样本生成方法。首先利用主成分分析(PCA)方法对地理环境原始变量进行线性相关性建模,基于提取的主成分,采用K-means算法对入侵物种样本进行聚类分析并计算各样本的地理环境相似度。在此基础上,通过建立基于主成分的入侵物种相似性度量与可信度计算框架来识别虚拟负样本。以长江经济带入侵物种一年蓬(Erigeron annuus)数据集为例,分析了整个区域虚拟负样本的可信度。结果表明,与空间随机采样和单类支持向量机采样相比,用本研究提出的方法生成的样本数据建立的logistic回归和支持向量机预测结果更优,验证了该方法的可行性与有效性。基于地理环境相似度的虚拟负样本抽样策略有助于解决由于随机采样而引起的误采样到潜在入侵点的难题,同时负样本的可信度能有助于识别不同等级的入侵物种适应区。     

Proportion of exotics and relatedness of host species mediate the positive effect of plant richness on the species richness of fruit flies

1. All else being equal, the greater the local species richness of plants, the greater the number of associated herbivore species. Because most herbivore insects feed on a subset of closely related plant species, plant phylogenetic diversity is expected to play a key role in determining the number of herbivore species. What is not well known, however, is how an increase in the species richness of exotic plants affects the species richness of herbivores. 2. In this study, we used plant–fruit fly interactions to investigate the influence of the proportion and species richness of exotic host plants on the species richness of herbivorous insects. We also tested whether the phylogenetic diversity of host plants increases when the number of exotic plant species increases. 3. We found that the species richness of fruit flies is more accurately predicted by the richness of native host plants than by total plant species richness (including both native and exotic species). The proportion of exotic host species and the phylogenetic diversity of host plants had negative and positive effects, respectively, on the species richness of fruit flies. 4. Our findings suggest that a positive effect of plant richness on herbivore richness occurs only when an increase in plant diversity involves plant species with which native herbivores share some evolutionary history.     

中国台湾和大陆蹄盖蕨属植物的生物地理学比较

蹄盖蕨属Athyrium Roth是个典型的东亚属,全世界估计约有160种,主要分布在亚洲东部的亚热带高山,少数在温带其他地区,中国有117种,是其分布中心。台湾和大陆的蹄盖蕨属植物关系尤为密切,是研究海峡两岸植物地理关系的一个很好的材料。台湾已知共计有蹄盖蕨类植物32种,包括狭义蹄盖蕨27种,介蕨2种,蛾眉蕨1种,假蹄盖蕨1种,假冷蕨1种,即使将待查实的4种蹄盖蕨除去,至少还有28种。其中除去7种大陆不产外, 21种均和大陆共有,占75%。况且,这7种与大陆种形态相近,是否同种异名、亚种或姊妹种关系还有待进一步研究;在台湾和大陆共有的16种狭义蹄盖蕨中有7种是台湾-西南间断分布。这不仅说明了台湾的蹄盖蕨属类植物和大陆的关系密切、有着共同的起源,而且说明台湾高地的植物区系和西南高地关系最为密切。运用生物系统学和分子系统学的方法研究和测定海峡两岸共有种种内、姊妹种或近缘种之间的遗传学关系(如:遗传一致度),进一步了解并量化台湾和大陆植物区系之间的历史和地理关系是必要的。     

苏州地区外来入侵植物组成及分布

为了解苏州外来入侵植物的种类组成及分布概况,对苏州地区6个县市(包括常熟、昆山、苏州、太仓、吴江和张家港)26个样点内不同生境中的外来入侵植物进行了调查分析.调查结果显示:每个样点有外来人侵植物7～25种,平均每个样点有17.9种.在26个样点中观察到外来入侵植物57种,隶属于19科45属;其中菊科(Compositae)种类最多(23种),占总种数的40.4％;豆科(Leguminosae)、玄参科(Scrophulariaceae)、禾本科(Poaceae)、伞形科(Apiaceae)、苋科(Amaranthaceae)和旋花科(Convolvulaceae)种类也较多.原产于北美洲和欧洲的种类分别有20和12种,分别占总种数的35.1％和21.0％;还有17种原产于美洲的其他区域,少数种类原产于非洲、西亚和地中海地区.在57种外来入侵植物中,草本植物有55种,非多年生植物有44种,分别占总种数的96.5％和77.2％.有18种的频度超过50％,其中加拿大一枝黄花(Solidago canadensis L.)和一年蓬[Erigeron annuus (L.) Pers.]的频度最高,分别达到96.15％和92.31％,且多度等级均属于极多级(Soc);空心莲子草[ Ahernanthera philoxeroides( Mart.) Griseb.]和白车轴草(Trifolium repens L.)的频度也均在80％以上,且多度等级也属于极多级(Soc).调查结果表明:苏州地区外来植物入侵现象比较严重.     

The species pool hypothesis: the necessity to shift emphasis

The species pool of a biological community is determined as a group of species that inhabit some area and potentially can be included in a given community. The species pool hypothesis, i.e. the assumption that the size of species pool strongly influences species richness of local community can be confirmed if there is positive linear relationship between these two variables. The results of hypothesis testing however are not obvious. For example, correlation between local richness and species pool size can be caused by their dependence on the third variable--capacity of environment. It seems that in case of decreasing area occupied by local community the environmental conditions become more important than species pool size. If that is true, the influence of species pool on local species richness is not significant. However one can estimate the degree of unsaturation of species pool on the basis of relationships between the number of species in small locations occupied by similar local communities and their species pool. We think, that study of local and regional species richness should shift the emphasis--from the analysis of species pool influence on local community richness to the estimation of historical, ecological and anthropogenic factors in variation of species pool size. The local species richness should be considered rather as a tool (allowing to compare the species capacity of biological communities), than as an object of such study.     

The factors controlling species density in herbaceous plant communities: an assessment

This paper evaluates both the ideas and empirical evidence pertaining to the control of species density in herbaceous plant communities. While most theoretical discussions of species density have emphasized the importance of habitat productivity and disturbance regimes, many other factors (e.g. species pools, plant litter accumulation, plant morphology) have been proposed to be important. A review of literature presenting observations on the density of species in small plots (in the vicinity of a few square meters or less), as well as experimental studies, suggests several generalizations: (1) Available data are consistent with an underlying unimodal relationship between species density and total community biomass. While variance in species density is often poorly explained by predictor variables, there is strong evidence that high levels of community biomass are antagonistic to high species density. (2) Community biomass is just one of several factors affecting variations in species density. Multivariate analyses typically explain more than twice as much variance in species density as can be explained by community biomass alone. (3) Disturbance has important and sometimes complex effects on species density. In general, the evidence is consistent with the intermediate disturbance hypothesis but exceptions exist and effects can be complex. (4) Gradients in the species pool can have important influences on patterns of species density. Evidence is mounting that a considerable amount of the observed variability in species density within a landscape or region may result from environmental effects on the species pool. (5) Several additional factors deserve greater consideration, including time lags, species composition, plant morphology, plant density and soil microbial effects.Based on the available evidence, a conceptual model of the primary factors controlling species density is presented here. This model suggests that species density is controlled by the effects of disturbance, total community biomass, colonization, the species pool and spatial heterogeneity. The structure of the model leads to two main expectations: (1) while community biomass is important, multivariate approaches will be required to understand patterns of variation in species density, and (2) species density will be more highly correlated with light penetration to the soil surface, than with above-ground biomass, and even less well correlated with plant growth rates (productivity) or habitat fertility. At present, data are insufficient to evaluate the relative importance of the processes controlling species density. Much more work is needed if we are to adequately predict the effects of environmental changes on plant communities and species diversity.     

Individuality and the existence of species through time

The individuality of species provides the basis for linking practical taxonomy with evolutionary and ecological theory. An individual is here defined as a collection of parts (lower-level entities) that are mutually connected. Different types of species individual exist, based on different types of connection between organisms. An interbreeding species is a group of organisms connected by the potential to share common descendants, whereas a genealogical species is integrated by the sharing of common ancestors. Such species definitions serve to set the limits of species at a moment of time and these slices connect through time to form time-extended lineages. This perspective on the nature of individuality has implications that conflict with traditional views of species and lineages: (1) Several types of connections among organisms may serve to individuate species in parallel (species pluralism); (2) each kind of species corresponds to a distinct kind of lineage; (3) although lineage branching is the most obvious criterion to break lineages into diachronic species, it cannot be justified simply by reference to species individuality; (4) species (like other individuals) have fuzzy boundaries; (5) if we wish to retain a species rank, we should focus on either the most- or least-inclusive individual in a nested series; (6) not all organisms will be in any species; and (7) named species taxa are best interpreted as hypotheses of real species. Although species individuality requires significant changes to systematic practice and challenges some preconceptions we may have about the ontology of species, it provides the only sound basis for asserting that species exist independently of human perception.     

Type Specimens and identity of the described species of Conus II. The species described by Solander, Chemnitz, Born, and Lightfoot between 1766 and 1786

Twenty-three species of Conus were described by authors other than Linnaeus between 1766 and 1786. Of these, 3 are Eocene species from England described by Solander in Brander (1766), and the remainder are Recent. Chemnitz (1777) described one valid species. Of the 10 species described by Born (1778), 7 are valid, 2 are junior synonyms of Linnaean species, and 1 is a nomen dubium. Solander in [Lightfoot] (1786) described 5 species, of which 3 are valid and 2 are junior synonyms of Linnaean species. Lightfoot (1786) described 4 species, of which 1 is valid and 3 are junior synonyms of Linnaean species.
Holotypes of 7 species and lectotypes of 3 species exist, and representatives of lecto-types of 10 species have been selected. All of these types are illustrated photographically.
Between 1758 and 1786, 60 species of Conus were described, of which 45 are now considered valid. Of these, 42 are Recent.     

庐山蛾类区系研究

庐山,地处中亚热带北沿,北纬29.35°,东经115.59°,属亚热带东部季风区域。庐山襟江带湖,雨量充沛,植物种类繁多,种子植物有1800余种,隶属158科642属。因此,庐山蛾类也较丰富。笔者于1975年5月开始,对庐山蛾类进行了调查,共鉴定出蛾类455种。现将庐山蛾类区系报告如下。 区系分析 庐山蛾类已鉴定出32科340届455种。区系情况如表。 从表可以看出:     

Trophic levels in community food webs

Summary Four concepts are considered for the trophic level of a species in a community food web. The long-way-up-level (or LU-level) of species A is the length of the longest simple food chain from a basal species (one with no prey in the web) to A. (A simple chain is a chain that does not pass through any given species more than once.) The short-way-up-level (SU-level) of species A is the length of the shortest chain from a basal species to A. The long-way-down-level (LD-level) of species A is the length of the longest simple chain from species A to a top species (one with no consumers in the web). The short-way-down-level (SD-level) of species A is the length of the shortest chain from species A to a top species. The stratigraphy of a web is the analogue for species of the pyramid of numbers for individuals: it is the frequency distribution of species according to level. The LU-, SU-, LD-, and SD-stratigraphies of the seven webs in the Briand-Cohen collection with 30 or more trophic species reveal no species with LU-level or LD-level more than 6, no species with SU-level more than 3, and no species with SD-level more than 2. In all seven webs, SD-levels are stochastically less than SU-levels: species tend to be closer to a top predator than to a basal species. Two stochastic models of food web structure (the cascade model and the homogeneous superlinear model) correctly predict that 95% or more of species should have LU-level and LD-level in the range 0–6. The models also correctly predict some details of the distribution of species in the SU- and SD-stratigraphies, particularly the fraction of species in level 1. The models do not, in general, correctly predict the distribution of species within the range 0–6 of LU-levels and LD-levels.     

The species concept as an emergent property of population biology

Resurgent interest in the genetics of population divergence and speciation coincides with recent critical evaluation of species concepts and proposals for species delimitation. An important result of these parallel trends is a slight but important conceptual shift in focus away from species diagnoses based on prior species concepts or definitions, and toward analyses of the processes acting on lineages of metapopulations that eventually lead to differences recognizable as species taxa. An advantage of this approach is that it identifies quantitative metapopulation differences in continuous variables, rather than discrete entities that do or do not conform to a prior species concept, and species taxa are recognized as an emergent property of population-level processes. The tension between species concepts and diagnosis versus emergent recognition of species taxa is at least as old as Darwin, and is unlikely to be resolved soon in favor of either view, because the products of both approaches (discrete utilitarian taxon names for species, process-based understanding of the origins of differentiated metapopulations) continue to have important applications.     

Ignoring ecological demands masks the real effect of urbanization: a case study of ground-dwelling spiders along a rural–urban gradient in a lowland forest in Hungary

We studied ground-dwelling spiders along a rural?Csuburban?Curban forest gradient representing increasing human disturbance using pitfall traps. We tested four known and two novel hypotheses: (1) increasing disturbance hypothesis (species richness is decreasing by disturbance); (2) matrix species hypothesis (the richness of open-habitat species is increasing by disturbance); (3) opportunistic species hypothesis (the richness of generalist species is increasing by disturbance); and (4) habitat specialist hypothesis (the number of the forest specialist species is decreasing by disturbance). As a consequence of urbanization, urban forests become drier and more open; thus, according to the new hypotheses, the number of (5) xerophilous species and (6) light-preferring species are increasing in the urban area. Our result did not support the increasing disturbance hypothesis, as the overall species richness increased from the rural sites to the urban ones. As predicted, the number of both the open-habitat and the generalist species increased towards the urban sites. The number of forest specialist species was higher in the suburban area than in the rural and urban area. Both xerophilous and light-preferring species were the most numerous in the urban area, supporting the xerophilous species and the light-preferring species hypotheses. Canonical correspondence analysis showed that the forest specialist species associated with the rural sites with higher amounts of decaying woods and more herbs or with the suburban sites with higher cover of leaf litter and higher relative humidity. Two generalist species and one open-habitat species were characteristic of urban sites with higher ground surface and air temperature.     

Species: the concept, category and taxon

The term species by itself is vague because it refers to the species concept, the species category and the species taxon, all of which are distinct although related to one another. The species concept is not primarily a part of systematics, but has always been an integral part of basic biological theory, It is based on evolutionary theory and applies only to sexually reproducing organisms. The species concept and the phyletic lineage concept are quite distinct although they are related to one another. The important aspect of the species concept is lack of gene flow between different species, and hence the defining criterion of the species is genetic isolation. The species concept is often considered as non‐dimensional, both in time and space. Species possess three different major properties, namely genetic isolation, reproductive isolation and ecological isolation; these properties evolve at different times and under the effect of different causes during the speciation process. Speciation requires an external isolating barrier during the initial allopatric phase in which genetic isolation evolves and must reach 100% efficiency. The subsequent sympatric phase of speciation occurs after the disappearance of the external isolating barrier when members of the two newly evolved species can interact with one another and exert mutual selective demands on one another. Much of the reproductive and ecological isolation evolves during this secondary sympatric phase. The species category is a rank in the taxonomic hierarchy and serves as the basis on which the diversity of organisms is described; it is not the same as the species concept. The species category applied to all organisms, sexually and asexually reproducing. The species taxon is the practical application of the species category in systematics with the recognition of species taxa requiring many arbitrary decisions. No single set of rules exist by which the species category can be applied to all organisms. Recognition of species taxa in asexually reproducing organisms is based on amount of variation and gaps in the variation of phenotypic features associated with ecological attributes of these organisms as compared with similar attributes in sympatric species taxa of sexually reproducing organisms. Species taxa are multidimensional in that they exist over space–time and often have fuzzy borders. Because recognition of species taxa, including those in sexually reproducing organisms, depends on many arbitrary decisions especially when dealing with broad geographical and temporal ranges, species taxa cannot be used as the foundation for developing and testing theoretical concepts in evolutionary theory which can only be done with the non‐dimensional species concept.     

A Preliminary Investigation on the Status of the Wildlife Trade in Guangxi,China

1IntroductionWildlifetradeisamain~mpetustoutilizewildlife.Thechangeinspeciesandvolumein-volvedinthewildlifetrademayreflectconservationstatus,dynamicsandexploitedlevelofwildliferesources.Thestudyonwildlifetradeisthetheoriticalbasisonwhichproposalsastolimittradeonrareorendangeredspeciescanbemade,andwithwhichfuturemonitoringofthetradecanbecompared.Theresultalsocanbeusedtoevaluateconservationeffectsofprotectionmeasuresandlawsforbiodiversityconservation.Itisofgreatsignificanceinguid-ingsustainable…     

Body size and measurement of species diversity in large grazing mammals

Species are by definition different from each other. This fact favours ranking rather than additive indices. However, ecologists have measured species diversity in terms of species richness, or by combining species richness with the relative abundance of species within an area. Both methods raise problems: species richness treats all species equally, while relative abundance is not a fixed property of species but varies widely temporally and spatially, and requires a massive sampling effort. The functional aspect of species diversity measurement may be strengthened by incorporating differences between species such as body size as a component of diversity. An index of diversity derived from a measure of variation in body size among species is proposed for large grazing mammals. The proposed diversity index related positively to species abundance, indicating that the use of body size as a surrogate for diversity is adequate. Because the proposed index is based on presence or absence data, the expensive and time consuming counting of individuals per species in each sampling unit is not necessary.     

牡丹江城市鸟类调查

2004年5月至2009年4月对牡丹江城市鸟类进行调查,共记录鸟类91种,隶属14目31科,占全国鸟类总种数的7.69%.说明牡丹江地区鸟类资源比较丰富,其丰富度指数1.967,均匀度指数0.653 8,Shannon-Wiener指数2.949.记录的91种鸟中留鸟26种,夏候鸟53种,冬候鸟3种,旅鸟9种,分别占总数28.6%、58.2%、3.3%、和9.9%.在居留型上,主要以夏候鸟为主.在区系组成上,东洋种5种,占5.5%,古北种54种,占59.3%,广布种32种,占35.2%,以古北种为主.记录到的91种鸟类中包括松雀鹰(Accipiter virgatus)、苍鹰(A.gentilis)等8种国家Ⅱ级保护野生动物.在所调查的鸟类中雀形目鸟类最多,15科52种.     

Species richness and altitude: a comparison between null models and interpolated plant species richness along the Himalayan altitudinal gradient, Nepal

We compare different null models for species richness patterns in the Nepalese Himalayas, the largest altitudinal gradient in the world. Species richness is estimated by interpolation of presences between the extreme recorded altitudinal ranges. The number of species in 100-m altitudinal bands increases steeply with altitude until 1,500 m above sea level. Between 1,500 and 2,500 m, little change in the number of species is observed, but above this altitude, a decrease in species richness is evident. We simulate different null models to investigate the effect of hard boundaries and an assumed linear relationship between species richness and altitude. We also stimulate the effect of interpolation when incomplete sampling is assumed. Some modifications on earlier simulations are presented. We demonstrate that all three factors in combination may explain the observed pattern in species richness. Estimating species richness by interpolating species presence between maximum and minimum altitudes creates an artificially steep decrease in species richness toward the ends of the gradient. The addition of hard boundaries and an underlying linear trend in species richness is needed to simulate the observed broad pattern in species richness along altitude in the Nepalese Himalayas.