洮河上游紫果云杉种群结构特征

该研究以洮河上游尕海-则岔自然保护区、卡车林区和冶力关林区的紫果云杉(Picea purpurea)天然种群为研究对象, 通过样地调查和数据统计, 绘制种群结构图, 编制静态生命表, 拟合并分析存活曲线, 运用数量化方法研究种群动态, 揭示种群生存现状, 预测种群发展趋势, 以期为该物种的保护、管理及结构恢复提供理论依据。结果显示: 3个林区紫果云杉种群自然更新能力强, 幼苗、幼树储量丰富, 幼小龄期死亡率普遍偏高; 尕海-则岔种群存活曲线符合Deevey-III型, 种群稳定结构完整, 卡车林区和冶力关林区种群存活曲线均符合Deevey-II型, 且均出现了局部衰退; 3个林区种群动态指数均大于0, 说明种群均属于增长型, 增长潜力为尕海-则岔>卡车>冶力关; 受随机干扰时卡车林区紫果云杉最敏感, 冶力关次之, 尕海-则岔种群最稳定。该研究表明: 竞争和自疏作用是造成紫果云杉幼小龄级个体存活率偏低的普遍因素, 3个林区不同的生存状况反映了紫果云杉种群在不同生境及生活史下生存能力的差异, 保护幼苗生存环境并提高幼苗质量和存活率是种群更新和发展的关键。尕海-则岔紫果云杉生存良好, 种群生存状况主要受自身生物学特性和环境因子的影响; 卡车林区主要受人为影响, 种群结构遭到破坏; 冶力关林区受分布限制, 造成种群结构不稳定, 须采取一定的人工措施来促进种群更新与增长。     

洮河上游紫果云杉种群结构特征

该研究以洮河上游尕海-则岔自然保护区、卡车林区和冶力关林区的紫果云杉(Picea purpurea)天然种群为研究对象,通过样地调查和数据统计,绘制种群结构图,编制静态生命表,拟合并分析存活曲线,运用数量化方法研究种群动态,揭示种群生存现状,预测种群发展趋势,以期为该物种的保护、管理及结构恢复提供理论依据。结果显示:3个林区紫果云杉种群自然更新能力强,幼苗、幼树储量丰富,幼小龄期死亡率普遍偏高;尕海-则岔种群存活曲线符合Deevey-III型,种群稳定结构完整,卡车林区和冶力关林区种群存活曲线均符合Deevey-II型,且均出现了局部衰退;3个林区种群动态指数均大于0,说明种群均属于增长型,增长潜力为尕海-则岔卡车冶力关;受随机干扰时卡车林区紫果云杉最敏感,冶力关次之,尕海-则岔种群最稳定。该研究表明:竞争和自疏作用是造成紫果云杉幼小龄级个体存活率偏低的普遍因素, 3个林区不同的生存状况反映了紫果云杉种群在不同生境及生活史下生存能力的差异,保护幼苗生存环境并提高幼苗质量和存活率是种群更新和发展的关键。尕海-则岔紫果云杉生存良好,种群生存状况主要受自身生物学特性和环境因子的影响;卡车林区主要受人为影响,种群结构遭到破坏;冶力关林区受分布限制,造成种群结构不稳定,须采取一定的人工措施来促进种群更新与增长。     

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。     

大熊猫栖息地亚高山针叶林结构和动态特征

亚高山针叶林是大熊猫适宜的栖息环境 ,其结构和动态规律严重影响大熊猫的生存和繁衍及其进化潜力的维持 ,是恢复退化大熊猫栖息地的唯一科学依据。通过样方法和中心点四分法调查了大熊猫栖息地 4个亚高山针叶林样地和该样地所在森林的 6 2个林窗 ,研究了该类森林的结构及其更新与大熊猫主食竹生长、林窗干扰的关系 ,以期揭示亚高山针叶林的动态规律 ,为大熊猫栖息地的恢复提供科学依据。研究结果表明 :岷江冷杉 Abies faxoniana和紫果云杉 Picea purpurea是亚高山针叶林的主体 ,其所构成的森林是大熊猫重要的栖息环境。岷江冷杉种群年龄呈现连续分布格局 ,而紫果云杉种群年龄呈间歇性分布 ,其在 2 5 0～ 5 0 0 a之间没有更新。该类森林中普遍存在着林窗干扰和更新现象 ,90 %的林窗下分布有岷江冷杉和紫果云杉更新的幼苗、幼树和大树。但林窗内不同树种更新密度不同 :岷江冷杉更新幼苗、幼树和大树占所有更新树种的 82 .5 % ,而紫果云杉和糙皮桦的更新幼苗、幼树和大树占 11.3%。岷江冷杉和紫果云杉的更新同时受林下大熊猫主食竹生长状况的影响 :主食竹盖度高 ,更新树种幼苗、幼树的密度低 ,即主食竹的生长抑制了岷江冷杉和紫果云杉的更新。     

极小种群野生植物细果秤锤树种群结构与动态特征

细果秤锤树(Sinojackia microcarpa)是中国特有极小种群植物之一,属国家Ⅱ级重点保护植物。为揭示该种群的生存潜力与濒危机制,为种群保护提供依据,采用样地调查法在浙江省建德市细果秤锤树自然集中分布区进行野外调查,以空间代替时间研究了细果秤锤树种群的结构特征,绘制了种群静态生命表及种群存活曲线,并应用种群动态和时间序列量化预测种群未来发展态势。结果表明:(1)细果秤锤树的径级、高度和冠幅结构均表明该种群龄级结构总体呈衰退型,种群幼年树淘汰率较高,中年树到老年树过渡阶段适应力增强,生长情况较前期稳定。(2)生活曲线属Deevey-Ⅲ型,早期死亡率高,生存分析揭示细果秤锤树种群具有前期锐减的动态特征。(3)时间序列分析预测在未来2、4、6、8个龄级后,细果秤锤树的年龄结构存在幼年个体数下降,中、老年树占优势的衰退风险。(4)种群动态指数表明该种群结构总体波动大,抗外界干扰能力较弱,环境对个体的选择作用较强。为促进种群自然更新,应加强就地保护措施,降低人为干扰对个体生存环境的威胁,提高幼苗至幼树转化率,实现种群恢复。     

长白山阔叶红松林红松种群年龄结构与数量动态特征

该研究以分布于长白山阔叶红松林内的红松(Pinus koraiensis)种群为对象, 通过编制种群静态生命表, 计算数量动态指数, 绘制存活曲线、死亡率曲线和消失率曲线, 应用4个生存函数并引入谱分析和时间序列预测模型, 分析红松种群年龄结构, 揭示其天然更新过程及未来发展趋势, 以期为野生红松种群的保护和恢复提供科学依据。结果显示: 红松种群数量变化具有阶段性, 幼龄(I-III龄级)和成龄(VII-X龄级)个体数量多, 中龄(IV-VI龄级)和老龄(XI-XIV龄级)个体数量少, 形成明显间断的两个优势年龄分布区。种群存活曲线趋近于Deevey-Ⅲ型, 表明幼龄个体死亡率高。忽略外部干扰时的总体数量动态变化指数大于>0, 表明红松种群为增长型; 考虑未来外部干扰时的种群动态变化指数趋近于0, 结合死亡率和消失率曲线呈现出连续先增后降的复杂动态变化趋势, 可知该种群受外界随机干扰时增长不明显。生存函数分析显示, 红松种群具有前期锐减、中期稳定、后期衰退的特点。谱分析表明红松种群天然更新呈周期性波动。未来2、3、4、5、6、7、8、9、10个龄级时间后, 红松幼、中龄个体数逐渐减少, 而成、老龄个体数量将逐渐增加。幼龄个体死亡率高、生存空间和资源条件有限, 老龄个体生理衰老明显是限制红松种群增长的主要原因。建议加强幼龄个体的抚育工作, 提高其存活率和生存质量; 保护和改善生存环境, 从而促进红松种群的自然更新和恢复。     

南京灵谷寺栓皮栎种群结构与动态

为了明晰南京灵谷寺栓皮栎种群动态特征,通过落叶阔叶混交林中栓皮栎种群样地调查,编制了种群静态生命表,并绘制其存活曲线和生存分析函数曲线,运用时间序列模型对种群的数量动态进行预测。结果表明:(1)在当前演替阶段,栓皮栎种群属于增长型,数量变化动态指数V_(pi)与V'_(pi)均大于0,存活曲线介于Deevey-Ⅰ型和Deevey-Ⅱ型之间,结合种群各龄级的统计分析及次生演替规律,说明栓皮栎种群正在由增长期向稳定期过渡,且时间序列预测表明过渡时期较长。另外,种群结构波动表明,经过强烈的环境筛选后,种群抵抗力增强,生命期望值短期内增加,死亡密度下降,种群数量稳定性提升。(2)在落叶阔叶混交林70多年的次生演替过程中,栓皮栎种群数量动态呈现出波动性变化特征,总体上趋于稳定,但幼苗幼树呈下降趋势。在今后的森林经营过程中,应人为促进栓皮栎幼苗幼树生长,保证其存活率,进而维持种群的增长与稳定,为灵谷寺落叶阔叶林可持续发展提供有利条件。     

长白山阔叶红松林紫椴种群结构与动态特征

紫椴(Tilia amurensis)为国家二级重点保护野生植物。以长白山北坡阔叶红松林内的紫椴种群为研究对象,通过建立种群静态生命表、绘制存活曲线、计算数量动态指数并引入生存函数和时间序列预测模型定量描绘其结构与动态特征。结果表明:1)种群年龄结构呈不规则金字塔形,幼龄阶段(Ⅰ-Ⅳ龄级)个体数之和占个体总数的67.26%。2)种群存活曲线接近Deevey-Ⅲ型,表明植株在幼龄阶段死亡率高。3)总体数量动态变化指数V_pi>V''_pi>0,表明紫椴种群为增长型,但V''_pi趋近于0,结合死亡率(q_x)和消失率(K_x)曲线呈现出连续性先增后降的复杂动态变化趋势,可知该种群不稳定且在干扰情况下增长趋势不明显。4)生存函数分析显示,种群在Ⅲ-Ⅳ龄级间达到平衡状态,尔后进入衰退期且从第Ⅷ龄级开始进入生理衰退。5)时间序列预测分析表明,在未来2、3、4、5、6、7、8、9、10龄级时间后,紫椴幼龄个体数逐渐减小,而中、成和老龄个体数量将逐渐增加,说明未来紫椴种群的增长主要依靠后者。生物学特性和生境是限制紫椴种群增长的主要原因。建议加强幼苗抚育工作,提高幼苗和小树的存活率,保护和改善生存环境,从而促进紫椴种群的自然更新和恢复。     

黄山常绿阔叶林优势种甜槠的种群动态与点格局分析

该研究以黄山森林植物多样性监测的3个大样地(钓桥庵、云谷寺、望瀑楼)内的优势种——甜槠(Castanopsiseyrei)种群为对象,分别从年龄结构、静态生命表、存活曲线、种群增长模型、生存分析和点格局分析等方面对甜槠种群的数量动态与空间分布格局进行了研究。结果表明：(1)研究区3个样地的甜槠均呈现种群幼苗众多,幼树储备丰富,且各样地个体数均随着龄级的增加逐渐减少,说明研究区甜槠种群均处于增长阶段,更新能力强,属于稳定型种群。(2)钓桥庵和望瀑楼样地的甜槠种群存活曲线均趋近于DeeveyⅡ型,两样地内甜槠各龄级均具有相近的死亡率,出现的3个死亡高峰分别在幼年期、近成熟前期和老龄期。(3)云谷寺样地的甜槠种群存活曲线趋近于DeeveyⅢ型,其前期死亡率较高,中期和后期死亡率比较低而且稳定。(4) 黄山森林植物中甜槠种群在小尺度呈显著的聚集性,随着尺度的增加则表现为随机分布。     

水杉原生母树种群结构与动态

为揭示水杉(Metasequoia glyptostroboides)原生母树种群的生存现状与数量动态,预测未来种群的发展趋势,基于野外种群调查数据,对种群结构与动态进行探讨。结果表明:(1)种群自然更新不良,DBH40 cm的个体仅占种群个体总数的4.5%,纺锤型的径级结构表明种群属衰退型。(2)种群幼龄个体存活率较低,中龄个体生存能力强,Ⅷ龄级之后存活量快速减少,存活曲线接近Deevey-Ⅲ型;种群死亡率和消失率整体上都随龄级增大而升高,均在Ⅸ龄级达到最大值。(3)生存分析表明,种群呈前期略减、中期波动、后期衰退的特征;幼龄阶段是种群生活史中的脆弱环节,Ⅷ龄级之后种群进入生理衰退期。(4)时间序列预测表明,未来8年期间种群幼龄和中龄个体不断减少,老龄个体渐增,种群整体的长期稳定性难以维持。总之,幼龄个体严重缺乏是种群趋于衰退的主要原因,保持适当的人工辅助恢复和加强现有植株及其生境保护是种群更新复壮的关键。     

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.     

Molecular phylogeny of Phebalium (Rutaceae: Boronieae) and related genera based on the nrDNA regions ITS 1+2

Parsimony analyses of the internal transcribed spacer regions of nuclear ribosomal DNA (ITS 1 & ITS 2) for 38 taxa sampled from the Phebalium group (Rutaceae: Boronieae) and two outgroups confirm that, with the exception of Phebalium sensu stricto and Rhadinothamnus, six of the currently recognised genera within the group are monophyletic. The data indicate that Phebaliums. str. is paraphyletic with respect to Microcybe, and Rhadinothamnus is paraphyletic with respect to Chorilaena. Rhadinothamnus and Chorilaena together are the sister group to Nematolepis. Drummondita, included as an outgroup taxon, clustered within the ingroup as sister to Muiriantha and related to Asterolasia.The phylogeny suggests that the evolution of major clades within a number of these genera (e.g. Phebalium) relates to vicariance events between eastern and south-western Australia. Leionema is an eastern genus, with the most basal taxon being the morphologically distinct Leionema ellipticum from northern Queensland. Leionema also includes one species from New Zealand, but this species (as with some others) proved difficult to sequence and its phylogenetic position remains unknown. Taxonomic changes at the generic level are recommended.The authors wish to thank Paul G.Wilson, PERTH, for advice and discussion, and Paul Forster, BRI, for collecting and providing material of Leionema ellipticum. The project was supported by a Melbourne University Postgraduate Award (to BM), the Australian Biological Resources Study (ABRS), Australian Systematic Botany Society and Wolf Den (Australia) Investments.     

New species and new combinations in Peruvian Orchidaceae

seventeen new species and combinations are proposed in the generaChondrorhyncha, Cischweinfia, Cochlioda, Eloyella, Encyclia, Kefersteinia, Koellensteinia, Macroclinium, Rodriguezia, Solenidiopsis, andStenia. All new species are illustrated. A key is provided for 2-flowered species ofMacroclinium, PeruvianSigmatostalix, and PeruvianStenia. Solenidium (Solenidiopsis) peruvianum Schltr. is lectotypified.     

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.

     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Phylogenetic investigations of Sordariaceae based on multiple gene sequences and morphology

The family Sordariaceae incorporates a number of fungi that are excellent model organisms for various biological, biochemical, ecological, genetic and evolutionary studies. To determine the evolutionary relationships within this group and their respective phylogenetic placements, multiple-gene sequences (partial nuclear 28S ribosomal DNA, nuclear ITS ribosomal DNA and partial nuclear β-tubulin) were analysed using maximum parsimony and Bayesian analyses. Analyses of different gene datasets were performed individually and then combined to generate phylogenies. We report that Sordariaceae, with the exclusion Apodus and Diplogelasinospora, is a monophyletic group. Apodus and Diplogelasinospora are related to Lasiosphaeriaceae. Multiple gene analyses suggest that the spore sheath is not a phylogenetically significant character to segregate Asordaria from Sordaria. Smooth-spored Sordaria species (including so-called Asordaria species) constitute a natural group. Asordaria is therefore congeneric with Sordaria. Anixiella species nested among Gelasinospora species, providing further evidence that non-ostiolate ascomata have evolved from ostiolate ascomata on several independent occasions. This study agrees with previous studies that show heterothallic Neurospora species to be monophyletic, but that homothallic ones may have a multiple origins. Although Gelasinospora and Neurospora are closely related and not resolved as monophyletic groups, there is insufficient evidence to place currently accepted Gelasinospora and Neurospora species into the same genus.     

Changes of dung beetle communities from rainforests towards agroforestry systems and annual cultures in Sulawesi (Indonesia)

Little is known about how tropical land-use systems contribute to the conservation of functionally important insect groups, including dung beetles. In a study at the margin of Lore Lindu National Park (a biodiversity hotspot in Central Sulawesi, Indonesia) dung-beetle communities were sampled in natural forest, young secondary forest, agroforestry systems (cacao plantations with shade trees) and annual cultures (maize fields), each with four replicates (n = 16 sites). At each site we used 10 pitfall traps, baited with cattle dung, along a 100 m transect for six 3-day periods. The number of trapped specimens and species richness at the natural forest sites was higher than in all land-use systems, which did not significantly differ. Each land-use system contained, on average, 75% of the species richness of the natural forest, thereby indicating their importance for conservation. However, a two-dimensional scaling plot based on NESS indices (m = 6) indicated distinct dung beetle communities for both forest types, while agroforestry systems and annual cultures exhibited a pronounced overlap. Mean body size of dung beetles was not significantly influenced by land-use intensity. Five of the six most abundant dung beetle species were recorded in all habitats, whereas the abundance of five other species was significantly related to habitat type. Mean local abundance and number of occupied sites were closely correlated, further indicating little habitat specialisation. The low dung beetle diversity (total of 18 recorded species) may be due to the absence of larger mammals in Sulawesi during historical times, even though Sulawesi is the largest island of Wallacea. In conclusion, the dung beetle fauna of the lower montane forest zone in Central Sulawesi appears to be relatively robust to man-made habitat changes and the majority of species did not exhibit strong habitat preferences.     

安徽牯牛降的丝孢菌Ⅰ

本文报导作者采自安徽枯牛降自然保护区的18种丝孢菌,分属于5个属,其中有3个新种:牛皮冻生尾孢(Cercospora paederiicola),山鸡椒假尾饱(Pseudocercospora litseae-cubebae),鸡血藤生假尾孢(P. millettiicola)和2个中国新纪录。文中对新种进行了描述及绘图,新记录种作了简要说明。研究的标本保存在中国科学院微生物研究所真菌标本室(HMAS)。