祁连山大野口流域青海云杉种群数量动态

种群数量动态揭示了种群的结构特征及其潜在的驱动机制，有助于预测种群未来的动态，进而为森林生态系统的保护与恢复提供理论依据。本研究基于10.2 hm²青海云杉动态监测样地数据，以种群径级结构代替年龄结构，编制静态生命表，绘制径级结构图、存活曲线、死亡率曲线、消失率曲线和4个生存分析函数曲线，分析青海云杉种群数量特征，并利用种群数量动态变化指数和时间序列模型对种群数量动态进行预测。结果表明：（1）青海云杉种群的年龄结构近似于倒"J"型，幼苗和小树储量丰富；（2）种群存活曲线趋近于Deevey-Ⅱ型，为稳定型种群，死亡率曲线和消失率曲线变化趋势基本一致，均在第2、8龄级出现高峰期；（3）生存率曲线呈下降趋势，累计死亡率曲线呈上升趋势，死亡密度曲线缓慢下降，而危险率曲线逐渐上升，该种群具有：前期减少、中期稳定、后期衰退的生长特点；（4）种群数量变化动态指数V_pi>0，表明该种群属于增长型种群，V_pi''>0且趋近于0，则表明该种群趋近于稳定型；（5）时间序列预测分析表明，在未来2、4、6、8个龄级时间后，种群呈稳定增长趋势。研究显示，祁连山大野口流域青海云杉种群为稳定增长型种群，只要未来不遭受强烈干扰，种群数量会保持逐渐增长。针对该种群幼龄个体在前期的更新过程死亡率较高情况，建议在今后的经营管理中应重点加强对第1、2龄级植株生存环境的保护和改善，提高幼苗和小树的存活率。     

灵空山油松种群年龄结构与动态分析

对山西灵空山自然保护区的油松（Pinus tabulaeformis）种群进行了调查,利用生存分析理论及谱分析理论,分析了油松种群径级结构和静态生命表,绘制了存活曲线,同时分析了种群数量的周期性。主要结果如下：（1）油松种群幼苗幼树个体数较多,中径级的个体数较稳定,而高径级由于种间竞争及环境因子的影响,个体数明显下降。（2）油松种群的存活曲线呈现Deevey-Ⅱ型。动态表现为前期增长,中期稳定,后期衰退。（3）油松种群波动存在小周期,但变化不大,说明油松种群发展较为稳定。     

濒危树种庙台槭种群数量特征及动态分析

庙台槭(Acer miaotaiense Tsoong)为我国三级保护植物,是秦岭特有的濒危树种,具有重要的经济价值和观赏价值。通过对庙台槭主要分布区野生资源进行调查,研究其种群的年龄结构、静态生命表、存活曲线和死亡曲线,用动态指数(Vpi、Vpi')和时间序列模型预测其种群发展趋势。结果显示,庙台槭种群幼龄个体多,中龄和老龄个体少,其生存曲线呈Deevey-Ⅲ型;静态生命表及相关曲线分析显示,庙台槭种群的存活率与径级表现出显著负相关,而种群死亡率曲线总体呈先下降后增加的趋势;种群数量动态分析显示,庙台槭种群整体结构处于增长型,在缺乏成年个体的情况下,种群对外部环境的抗干扰能力下降;时间序列预测发现,经过幼苗、幼树阶段,同一时间曲线的庙台槭种群数量在高径级所占比例略有增加,但高龄级个体相对较少;庙台槭分布地区的主要植被类型为落叶阔叶林和常绿阔叶林,但庙台槭个体受保护较少,人为活动及病虫害影响较大,天然更新困难,生存和保护状况不容乐观。     

武夷山米槠种群结构及谱分析

在武夷山自然保护区对米槠种群数量动态进行了系统研究,编制了静态生命表,分析了存活曲线和死亡曲线,同时应用谱分析方法分析种群数量的动态变化。结果表明,武夷山自然保护区米槠种群基本属于进展型或稳定型,幼龄级个体多,中老龄级个体少。不同海拔的种群密度存在差异,其中C种群密度最大;静态生命表显示,种群在Ⅰ、Ⅱ径级时死亡率较高,随着年龄增加,死亡率逐渐降低,但到了Ⅳ、Ⅴ径级,由于生理衰老死亡率又上升;种群期望寿命在Ⅰ、Ⅱ径级较高,随着年龄增加,期望寿命逐渐下降;不同海拔的米槠种群的存活曲线均接近于Deevey Ⅲ 型。米槠种群自然更新过程存在明显的周期。     

西南特有濒危植物大王杜鹃种群结构及动态特征

为了揭示高山杜鹃种群生存潜力和濒危原因,以西南特有濒危植物大王杜鹃(Rhododendron rex subsp. rex)为研究对象,通过对云南省轿子雪山和小百草岭2个大王杜鹃自然种群的野外植株胸径及数量的调查,采用空间代替时间的方法建立大王杜鹃种群的径级结构、静态生命表并绘制种群存活曲线,阐明其种群的结构特征,利用种群数量动态预测和时间序列预测来分析种群未来的发展趋势。结果表明：(1)云南轿子雪山和小百草岭两个样地大王杜鹃均表现出第Ⅰ~Ⅱ龄级个体不足的现象,尽管两个样地内大王杜鹃种群仍表现为稳定型种群,但其均对外界干扰具有很高的敏感性。(2)大王杜鹃存活曲线在云南轿子雪山和小百草岭2个样地都趋于Deevey Ⅱ型,个体平均生存能力的期望值均在幼年(Ⅰ和Ⅱ龄级)个体中最大,死亡率和消失率曲线的变化趋势基本一致。(3)时间序列预测分析表明,云南轿子雪山大王杜鹃种群在未来2、4、6年龄级后总体均呈下降趋势,种群面临衰退危险;小百草岭样地内,大王杜鹃种群总体上呈增长趋势,种群具有一定的恢复潜力。建议加强大王杜鹃自然种群生境的保护与管理从而维持其种群自然更新与发展的能力。     

木兰围场天然次生林优势种群的结构与动态

为了阐明木兰围场天然次生林优势种群的结构和动态特征,对群落乔木层组成以及优势种群的径级结构、静态生命表、存活曲线、死亡曲线、生存函数和时间序列预测等进行研究.结果表明: 群落乔木层有9个种群,其中,五角枫、蒙古栎、糠椴和白桦种群为群落的优势种群;五角枫和糠椴种群存活曲线接近于Deevey-Ⅱ型,蒙古栎种群存活曲线趋于Deevey-Ⅲ型,白桦种群存活曲线为Deevey-Ⅱ型;随着径级的增加,各优势种群的死亡率和消失率曲线呈现相似的变化趋势,五角枫、蒙古栎、糠椴种群的消失率和死亡率分别在Ⅳ、Ⅰ和Ⅰ径级下出现最大值,而白桦种群在各径级呈现稳定的变化趋势;4种生存函数曲线分析表明,五角枫、蒙古栎和糠椴种群具有前期锐减、中后期相对稳定的特点;白桦种群数量波动不明显,具有较稳定的特点.种群数量的时间序列预测表明,白桦种群小径级(Ⅰ～Ⅱ级)个体数量逐渐减少,种群未来有趋于衰退的趋势,五角枫、蒙古栎和糠椴种群趋于相对稳定.推测该次生林将逐步演替为以五角枫、蒙古栎和糠椴为主要树种的天然次生林.     

3种海桑属濒危红树植物的种群结构与动态特征

以3种海桑属（Sonneratia）濒危红树植物——海南海桑（Sonneratia×hainanensis）、拟海桑（S.×gulngai）、卵叶海桑（S. ovata）为研究对象,通过编制静态生命表,绘制存活曲线、死亡率和消亡率等曲线分析其种群结构,并用生存分析与时间序列对其未来的数量动态进行预测,以阐述其种群结构特征和动态变化规律,为海桑属濒危植物种群的保护和恢复提供基础资料和科学依据。结果显示：（1）卵叶海桑种群结构为增长型;而由于缺乏幼龄个体,海南海桑和拟海桑均为衰退型。（2）三者的种群存活曲线都表现为Deevey-Ⅱ型,各种群的死亡率和消失率曲线的变化趋势一致,并随着龄级的增加呈波状上升趋势,其中海南海桑和拟海桑均在老龄阶段遇到了障碍,而卵叶海桑幼龄个体的发展遇到了瓶颈。（3）海南海桑和拟海桑种群自我更新能力较差,未来种群数量将逐渐衰退。卵叶海桑种群具有良好的恢复潜力,未来种群数量将逐步增加,但由于其种群个体数随龄级增加呈衰减趋势,若继续保持这种态势,将有可能导致龄级断层现象。（4）人类的养殖活动导致原有生境破碎化,产生了一系列不适宜种子萌发与幼苗生长的环境因子（光照、盐度、...     

珍稀植物银砂槐中国分布区的种群结构与动态分析

通过对中国唯一银砂槐(Ammodendron bifolium)分布区———新疆伊犁河谷地塔克尔莫乎尔沙漠狭窄区域的样地调查和数据统计分析,绘制了银砂槐自然种群的径级结构图,编制了种群的特定时间生命表,分析了存活曲线、死亡率曲线和寿命期望等重要参数,并运用时间序列模型预测种群数量动态。结果表明:(1)研究区内银砂槐种群结构中小径级个体较多,即Ⅰ~Ⅲ径级占70.4%,Ⅳ~Ⅶ径级占27.62%,Ⅷ~Ⅹ径级仅占1.98%,种群整体结构属于增长型,但Ⅰ径级个体数少于Ⅱ径级,种群的自然更新相对较差。(2)静态生命表分析结果表明,随着径级的增加银砂槐种群死亡率大致为上升趋势,且种群内基径超过3.5cm(Ⅷ径级)的银砂槐数量迅速下降,即研究区内银砂槐基径越接近Ⅷ径级就越接近其生理寿命。(3)研究区内银砂槐的存活曲线基本接近DeeveyⅢ型,但Ⅰ径级存活数低于Ⅱ径级,Ⅱ径级后存活数量迅速下降,说明该种群幼苗补充量较少,自然更新受阻。(4)时间序列分析表明,随着时间推移,种群未来会呈现老龄个体增加的趋势。研究认为,新疆伊犁河谷地的银砂槐种群的生长发育主要受限于其自身的生物学特性和种内竞争,其种群的长期稳定维持较为困难,现有植株及生境斑块的妥善保护和适当的人工辅助措施是该区银砂槐种群恢复的关键。     

茂兰喀斯特森林梓叶槭种群结构与数量动态

梓叶槭是中国特有的珍稀濒危树种,国家二级保护植物,为了明确梓叶槭种群的结构特征及其种群生存现状,该研究在黔、桂交界处的茂兰国家级喀斯特森林自然保护区选取典型森林群落,应用每木调查法从梓叶槭高度（H）、径级结构、静态生命表、存活曲线和寿命期望等方面分析梓叶槭种群结构及其数量动态规律,为退化喀斯特森林生态系统的恢复重建提供理论依据。结果表明：（1）茂兰喀斯特森林中梓叶槭在群落中的重要值较低 ［槽谷(0.255),漏斗(0.243),坡地(0.188）］为非优势种。（2）梓叶槭种群主要分布在槽谷森林、漏斗森林和坡地森林等3种不同地形部位的群落类型中,在槽谷森林中分布数量最多,其次是漏斗森林,坡地森林中长势较差且数量最少。（3）梓叶槭在不同生境均严重缺乏Ⅰ径级 ［胸径（DBH） < 2.5 cm,H < 33 cm］ 个体,但Ⅱ径级（DBH < 2.5 cm,H = 33 cm）个体占较大的比例,中、大径个体较少,表现为稳定型种群。（4）不同生境梓叶槭种群存活数（除Ⅰ径级）随着径级增加而降低,死亡率（q_x）和致死力（K_x）曲线大致呈上升趋势,生命期望单调下降,且Ⅰ径级在不同生境的死亡率均为负数,说明其幼苗严重不足,存活曲线趋于DeeveyⅡ型。研究认为,茂兰喀斯特森林中梓叶槭种群幼苗在发育过程中死亡率较高,而且受到的种间竞争较为激烈,加之茂兰喀斯特生境的严酷性和土壤营养空间缺乏,造成梓叶槭生长速度缓慢,故梓叶槭种群的衰退与严酷的喀斯特生境、人为干扰有关。     

准噶尔盆地东南缘梭梭种群结构与动态研究

通过样地调查和数据统计分析,对准噶尔盆地东南缘梭梭种群现状绘制径级结构图,编制生命表、分析存活曲线、死亡率曲线和寿命期望等参数,并运用时间序列模型预测种群数量动态.结果表明:种群整体结构属于增长型,但梭梭种群幼苗个体少,Ⅰ、Ⅱ龄级个体数目少于Ⅲ龄级的个体数目.存活曲线基本接近DeeveyⅢ型,种群偏离典型存活曲线的程度与幼苗缺乏有关;环境因素和人为干扰的影响,梭梭在Ⅲ～V龄级死亡率较高,种群在第Ⅳ级出现死亡高峰,且只有少量幼年个体能进入成年阶段,个体平均生存能力的期望在第Ⅳ级最大;时间序列分析表明,在未来第Ⅱ、Ⅳ、Ⅵ、Ⅷ龄级的个体会呈现老龄个体增加的趋势,种群稳定性长期维持困难.适当的人工辅助恢复和现有植株及生境的保护是保持梭梭种群自然更新和种群恢复的关键.     

Foreign exploration for Scirtothrips perseae Nakahara (Thysanoptera: Thripidae) and associated natural enemies on avocado (Persea americana Miller)

Scirtothrips perseae Nakahara was discovered attacking avocados in California, USA, in 1996. Host plant surveys in California indicated that S. perseae has a highly restricted host range with larvae being found only on avocados, while adults were collected from 11 different plant species. As part of a management program for this pest, a “classical” biological control program was initiated and foreign exploration was conducted to delineate the home range of S. perseae, to survey for associated natural enemies and inventory other species of phytophagous thrips on avocados grown in Mexico, Guatemala, Costa Rica, the Dominican Republic, Trinidad, and Brazil. Foreign exploration efforts indicate that S. perseae occurs on avocados grown at high altitudes (>1500 m) from Uruapan in Mexico south to areas around Guatemala City in Guatemala. In Costa Rica, S. perseae is replaced by an undescribed congener as the dominant phytophagous thrips on avocados grown at high altitudes (>1300 m). No species of Scirtothrips were found on avocados in the Dominican Republic, Trinidad, or Brazil. In total, 2136 phytophagous thrips were collected and identified, representing over 47 identified species from at least 19 genera. The significance of these species records is discussed. Of collected material 4% were potential thrips biological control agents. Natural enemies were dominated by six genera of predatory thrips (Aeolothrips, Aleurodothrips, Franklinothrips, Leptothrips, Scolothrips, and Karnyothrips). One genus each of parasitoid (Ceranisus) and predatory mite (Balaustium) were found. Based on the results of our sampling techniques, prospects for the importation of thrips natural enemies for use in a “classical” biological control program in California against S. perseae are not promising.     

Taxonomic status of the species of the green algal genusNeochloris

Komárek has recently reviewed the various species assigned to the green algal genusNeochloris Starr (Chlorococcales, Chlorococcaceae) and removed those with uninucleate vegetative cells to a new genus,Ettlia. Watanabe & Floyd, unaware ofKomárek's work, also reviewed the species ofNeochloris and distributed them among three genera—Neochloris, Chlorococcopsis gen. nov., andParietochloris gen. nov.—on the basis of details of the covering of the zoospore and the arrangement of the basal bodies of the flagellar apparatus. This paper reconciles these two treatments and makes additional recommendations at the ranks of genus, family, order, and class.     

Die GattungKarschia — Bindeglied zwischen bitunicaten Ascomyceten und lecanoralen Flechtenpilzen?

The genusKarschia, in the earlier sense, including saprophytes and parasites on lichens, has been thought to be a non-lichenized parallel genus of the lichen genusBuellia. Modern workers included it on the one hand inBuellia, on the other hand combined it with bitunicate ascomycetes. It is now proved thatKarschia is heterogeneous and contains but superficially similar members both of the genusBuellia of theLecanorales and of typical or masked bitunicateAscomycetes. Therefore, it can not be regarded as a link betweenLecanorales andDothideales. The type species ofKarschia belongs to theDothideales.

     

Systematic significance of mature embryo of bamboos

The mature embryo of seven species belonging to five genera of Indian bamboos is described. In all these the basic pattern of embryo organisation is same: the scutellar and coleoptilar bundles are not separated by an internode, the epiblast is absent, the lower portion of the scutellum and the coleorhiza are separated by a cleft and the margins of embryonic leaves overlap. The features unique to fleshy fruited bamboos are: presence of a massive scutellum, the juxtaposition of plumule and radicle and the occurrence of a bud in the axil of the coleoptile. The fleshy fruit bearing bamboos should be classified into one group, the tribeMelocanneae. Evidence is provided to recognise additional groups in the subfamilyBambusoideae.     

Phylogeny of cardinalfishes (Teleostei: Gobiiformes: Apogonidae) and the evolution of visceral bioluminescence

The cardinalfishes (Apogonidae) are a diverse clade of small, mostly reef-dwelling fishes, for which a variety of morphological data have not yielded a consistent phylogeny. We use DNA sequence to hypothesize phylogenetic relationships within Apogonidae and among apogonids and other acanthomorph families, to examine patterns of evolution including the distribution of a visceral bioluminescence system. In conformance with previous studies, Apogonidae is placed in a clade with Pempheridae, Kurtidae, Leiognathidae, and Gobioidei. The apogonid genus Pseudamia is recovered outside the remainder of the family, not as sister to the superficially similar genus Gymnapogon. Species sampled from the Caribbean and Western Atlantic (Phaeoptyx, Astrapogon, and some Apogon species) form a clade, as do the larger-bodied Glossamia and Cheilodipterus. Incidence of visceral bioluminescence is found scattered throughout the phylogeny, independently for each group in which it is present. Examination of the fine structure of the visceral bioluminescence system through histology shows that light organs exhibit a range of morphologies, with some composed of complex masses of tubules (Siphamia, Pempheris, Parapriacanthus) and others lacking tubules but containing chambers formed by folds of the visceral epithelium (Acropoma, Archamia, Jaydia, and Rhabdamia). Light organs in Siphamia, Acropoma, Pempheris and Parapriacanthus are distinct from but connected to the gut; those in Archamia, Jaydia, and Rhabdamia are simply portions of the intestinal tract, and are little differentiated from the surrounding tissues. The presence or absence of symbiotic luminescent bacteria does not correlate with light organ structure; the tubular light organs of Siphamia and chambered tubes of Acropoma house bacteria, those in Pempheridae and the other Apogonidae do not.     

Biological control of three floating water weeds,<Emphasis Type="Italic">Eichhornia crassipes,Pistia stratiotes</Emphasis>, and <Emphasis Type="Italic">Salviniamolesta</Emphasis> in the Republic of Congo

Since 1999, four specific weevils (Coleoptera, Curculionidae) were released in the Republic of Congo against three exotic floating water weeds: Neochetina eichhorniae Warner and N. bruchi Hustache against water hyacinth, Neohydronomus affinis Hustache against water lettuce, and Cyrtobagous salviniae Calder and Sands against water fern. Recoveries of exotic weevils were made from all 24 release sites except one, and all four species have established and spread (up to 800 km for water hyacinth weevils). Within a few years of releases, control of water fern and water lettuce was such that fishing and navigation could be resumed, while reductions of water hyacinth populations were only beginning.     

A molecular phylogeny of Hebeloma species from Europe

In order to widen the scope of existing phylogenies of the ectomycorrhizal agaric genus Hebeloma a total of 53 new rDNA ITS sequences from that genus was generated, augmented by sequences retrieved from GenBank, and analysed using Bayesian, strict consensus and neighbour joining methods. The lignicolous Hebelomina neerlandica, Gymnopilus penetrans, and two species of Galerina served as outgroup taxa. Anamika indica, as well as representatives of the genera Hymenogaster and Naucoria, were included to test the monophyly of Hebeloma, which is confirmed by the results. Hebeloma, Naucoria, Hymenogaster and Anamika indica cluster in a strongly supported monophyletic hebelomatoid clade. All trees largely reflect the current infrageneric classification within Hebeloma, and divide the genus into mostly well-supported monophyletic groups surrounding H. crustuliniforme, H. velutipes, H. sacchariolens, H. sinapizans, and H. radicosum, with H. sarcophyllum being shown at an independent position; however this is not well supported. The section Indusiata divides with strong support into three groups, the position of the pleurocystidiate Hebeloma cistophilum suggests the possible existence of a third subsection within sect. Indusiata. Subsection Sacchariolentia is raised to the rank of section.