生物入侵机制研究进展

本文从外来种本身的生物学特性,外来种与新栖息地土著种之间的相互作用,群落生物多样性对入侵种的抵抗能力,新栖息地生态环境变化对入侵种的影响等方面综述了近年来有关生物入侵机制的研究进展,并探讨了研究方法的发展和亟待解决的问题,大量的研究表明生物入侵机制是极为多样的,可能没有一般的,通用的机制,阐明生物入侵的机制,对推动生态学理论的发展和控制有害外来种有重要意义。     

全球气候变化与生物入侵

近年来,人们能越来越明显地感受到全球气候的变化,例如气温升高、降水量增加和极端气候事件增多等。而生物入侵由于对生物多样性和经济造成了巨大影响,也逐渐受到研究人员和各国政府的重视。全球气候变化因素众多,不可避免地影响到了生物入侵进程和成功率,而大规模生物入侵对森林和海滨生态系统的破坏反过来也将对全球气候造成影响。本文探讨了全球气候变化与生物入侵的关系,以及造成这些关系的相关机理。     

生物入侵对鸟类的生态影响

生物入侵是全球生物多样性面临的最主要威胁之一, 入侵种在改变入侵地环境的同时也使当地的生物受到极大影响。鸟类在生态系统中处于较高的营养级, 生态系统中任何一个环节的变化都可能对鸟类造成一定的影响。本文回顾了哺乳动物、鸟类、无脊椎动物和植物等不同生物类群的入侵对本地鸟类生态影响方面的研究进展。外来生物对鸟类的影响主要表现在以下几方面: (1)外来哺乳动物对成鸟、幼鸟或鸟卵的捕食作用; (2)外来鸟类与本地鸟类竞争栖息地和食物资源, 与当地的近缘种杂交而造成基因流失; (3)外来无脊椎动物改变本地鸟类的栖息环境和食物状况, 甚至直接捕食本地鸟类; (4)外来植物入侵改变入侵地的植物群落组成和结构, 造成本地鸟类的栖息地丧失或破碎化, 并通过改变入侵地生态系统的食物链结构而对高营养级的鸟类产生影响。最后, 作者还提出了该领域有待解决的问题和今后可能的研究方向。     

外来生物入侵中的达尔文归化谜团

针对外来生物入侵问题,达尔文在《物种起源》中提出了相反的两个假说,分别主张和本地物种亲缘关系近和远的外来物种更容易归化和入侵.这两个假说综合在一起现在被称为达尔文归化谜团.在沉寂了百余年后,随着系统发育和功能性状分析在生态学中的广泛运用,该谜团在近30年内迅速成为生物入侵领域研究的热点和前沿问题.但由于不同的研究往往得出矛盾的结论,错综复杂的研究结果使得该谜团的和解仍面临很大困难.本文梳理了达尔文归化谜团的内涵和外延,回顾了该谜团研究的发展历程和脉络,总结了近年来从空间尺度、入侵阶段、差异度量方式和控制性实验等角度尝试和解这一谜团的探索及其进展.本文认为,充分考虑环境梯度和人类活动的影响,综合分析入侵进程中的本地群落特征和动态,选择恰当的统计方法和零模型,并将该谜团的研究思路和理念引入到疾病生态学等诸多相关领域,是未来达尔文归化谜团研究的重点方向.对这一长达160余年谜团的探索,不仅有助于发展和完善入侵生态学理论,也将为外来生物入侵的防控提供重要科学指导.     

红树林生物入侵研究概况与趋势

为了掌握目前红树林生物入侵研究实况, 基于ISI Web of Science数据库和HistCite文献分析软件, 我们进行了全面系统的文献检索与分析。结果显示, 国内外有关红树林生物入侵研究文献绝大部分针对植物入侵, 有关动物与微生物的研究寥寥无几; 研究区域集中于中国华南与东南沿海(尤其是珠江口、雷州半岛西侧)和美国东南海岸及夏威夷群岛。无瓣海桑(Sonneratia apetala)是否构成入侵, 一直备受争议, 有待更长远论证, 但须谨慎引种。互花米草(Spartina alterniflora)与微甘菊(Mikania micrantha)是世界性恶草, 生长迅速, 繁殖力强, 竞争与化感作用明显, 二者已在红树林生态系统中爆发入侵, 显著降低了红树林微生境质量, 并改变了底栖生物群落结构。Rhizophora mangle作为外来红树植物入侵夏威夷群岛, 改善了沉积条件, 丰富了底栖生物群落, 但需从全球尺度考察入侵后果。目前, 红树林生物入侵研究才刚起步, 针对性研究局限于入侵对红树林生态系统结构和功能产生的效应。相关入侵机制缺乏探索, 现有防治方法大多只是借鉴其他被入侵系统的防治方法。今后, 红树林生物入侵研究应持续加深入侵现状和入侵效应的探索与评价, 加快开展入侵机制和防治方法的研究应用, 以及对生态系统服务的影响评价。健全红树林生物入侵管理体系, 将在防治红树林生物入侵实践中发挥主导作用。     

中国生物安全研究展望学术研讨会纪要

外来种入侵是一个广泛存在的具有相当长历史进程的问题 ,随着科学技术水平的发展 ,特别是交通运输工具的发展 ,人们有意或无意地把一个地域上的物种携带到另一个地域上 ,这些被转移的物种在新地域上生长并扩散。近些年来由于外来种入侵的问题越来越突出 ,不仅是导致生物多样性丧失的主要原因 ,而且威胁着全球的生态环境和经济发展 ,因此已经引起了公众、科学家、国际组织和各国政府的普遍关注。如 :2 0 0 1年生物多样性日的主题就是外来种及对生态系统的影响 ;1996年环境问题委员会 (ＳＣＯＰＥ)为了实施《生物多样性公约》有关外来种防止、…     

生物入侵: 中国学者面临的转化生态学机遇与挑战

今天,乘坐飞机长途旅行已是一件太普通不过的事情了,我们可以在不到一天的时间内到达世界的任何大城市.在我们的孩提时代,世界大城市是‘那么的遥不可及,而今只不过是邻近的"小村落"而已,世界变得越来越小.近代技术革新所带来的空间上的相对变小不仅给我们人类的各种交往和商业活动带来了便捷,而且也有助于生物物种越过自然的物理屏障,进行快速和低风险的长距离扩散,从而重塑物种的分布区.从这种意义上来说.全球化就像地质事件一样,对物种的分布区产生着深刻的影响.就全球范围来看,由人类有意或无意"嫁到"新的地理分布区的物种总数可能已达到50万种之多(Pimentel et a1..2001).     

生物入侵的进化生物学

生物入侵(Biological invasion) 是指一种生物在人类活动的影响下,从原产地进入到一个新的栖息地,并通过定居(Colonizing) 、建群( Establishing) 和扩散(Diffusing) 而逐渐占领该栖息地,从而对当地土著生物和生态系统造成负面影响的一种生态现象。       

北美车前(Plantago Virginica)和车前(P.asiatica)分布格局的分形分析

北美车前 (ＰｌａｎｔａｇｏｖｒｉｇｉｎｉｃａＬ .)是我国东南地区的一种外来杂草 ,该杂草在浙江、江苏、上海、江西等省区有分布 ,多见于田梗路边、住宅四周、抛荒地、公路两侧等人畜出没频繁的地段 ,其种群生长迅速 ,呈现出生态爆发态势 ,是一种典型的生态入侵种。分形理论已被广泛地应用于自然科学、社会科学中的众多领域。在生态学领域 ,应用分形维数能够客观地表达种群的分布式样 ,同时也能反映种群占有空间、资源利用的能力[1～ 6 ] 。本研究以新入侵种北美车前为对象 ,并与我国境内分布较广的杂草车前 (Ｐ .ａｓｉａｔｉｃａ)作比…     

北美地区一新外来入侵种——花曲柳窄吉丁

介绍了原产亚洲的北美地区的一种新的入侵种——花曲柳窄吉丁AgrilusplanipennisFairmaire的国内外研究进展,对该虫的分类地位、形态特征、分布与起源、寄主、生物学特性等进行了综述,提出了作为入侵种需要进一步研究的方向。     

Large‐scale patterns of tree species richness and the metabolic theory of ecology

The metabolic theory of ecology (MTE) endeavours to explain ecosystem structure and function in terms of the effects of temperature and body size on metabolic rate. In a recent paper (Wang et al., 2009, Proceedings of the National Academy of Sciences USA, 106 , 13388), we tested the MTE predictions of species richness using tree distributions in eastern Asia and North America. Our results supported the linear relationship between log‐transformed species richness and the inverse of absolute temperature predicted by the MTE, but the slope strongly depends on spatial scale. The results also indicate that there are more tree species in cold climate at high latitudes in North America than in eastern Asia, but the reverse is true in warm climate at low latitudes. Qian & Ricklefs (2011, Global Ecology and Biogeography, 20 , 362–365) recently questioned our data and some of the analyses. Here we reply to them, and provide further analyses to show that their critiques are primarily based on unsuitable data and subjective conjecture.     

Latitude,tree species diversity and the metabolic theory of ecology

The latitudinal diversity gradient (LDG) has been known for over a century, but its origin remains poorly understood. Because both latitude and species richness are broadly related to temperature, environmental temperature has been proposed as a driver of the LDG. Recently, Wang et al. (2009, Proceedings of the National Academy of Sciences USA, 106 ,13388–13392) used datasets compiled from tree distributions in eastern Asia and North America to compare the species richness?temperature relationship between the two regions at several spatial scales and framed their analyses in the context of the metabolic theory of ecology. Here, we show that their datasets lack comparability between eastern Asia and North America and that some aspects of their analyses probably biased their results, casting doubt on some of their conclusions.     

北美外来植物中原产东亚类群的学名考证

作者在整理北美外来入侵植物中发现一些起源(或主要分布)于东亚植物的学名,在北美乃至欧洲使用非常混乱.本文特将有关重要类群整理出来,包括异名、原产地、北美的分布以及必要的讨论等.     

东亚——北美东部间断透骨草属的扩增片段长度多态性

透骨草属(Phryma)是一个单种属,间断分布于东亚与北美东部.尽管东亚与北美东部居群形态差异非常小,但分子变异却非常明显.本研究进一步运用AFLP两对引物来衡量透骨草属的遗传多样性并评估其形态保守性.结果发现透骨草的遗传差异主要存在于两大洲的居群之间.聚类与PCA分析显示透骨草分成两大支与其地理分布相吻合,一支全部来自东亚,另一支则是北美东部的居群.我们的结果强烈支持透骨草东亚--北美东部居群存在明显的遗传分化和形态保守.     

A cytological study on Kelloggia (Rubiaceae), an intercontinental disjunct genus between eastern Asia and western North America

A cytological study was carried out for the first time on four populations of the only two species of Kelloggia (Rubiaceae), which occur disjunctly in eastern Asia (K. chinensis Franch.) and western North America (K. galioides Torr.). The consistent mitotic prophase chromosome condensation pattern and interphase nuclei type were determined for both species. The chromosome base number of the genus is suggested to be x=11. The karyotype of 2n=22=2x=16m+6sm was examined for both species. The karyotypical asymmetry of 1A and 2A was found in K. chinensis and K. galioides, respectively. According to the predominant evolutionary direction of karyotype asymmetry in angiosperms, K. galioides (2A) seems slightly more evolved than K. chinensis (1A). Our finding is consistent with the hypothesis of the Old World origin of Kelloggia based on molecular study.     

Evidence for serial founder events during the colonization of North America by the yellow fever mosquito,Aedes aegypti

The Aedes aegypti mosquito first invaded the Americas about 500 years ago and today is a widely distributed invasive species and the primary vector for viruses causing dengue, chikungunya, Zika, and yellow fever. Here, we test the hypothesis that the North American colonization by Ae. aegypti occurred via a series of founder events. We present findings on genetic diversity, structure, and demographic history using data from 70 Ae. aegypti populations in North America that were genotyped at 12 microsatellite loci and/or ~20,000 single nucleotide polymorphisms, the largest genetic study of the region to date. We find evidence consistent with colonization driven by serial founder effect (SFE), with Florida as the putative source for a series of westward invasions. This scenario was supported by (1) a decrease in the genetic diversity of Ae. aegypti populations moving west, (2) a correlation between pairwise genetic and geographic distances, and (3) demographic analysis based on allele frequencies. A few Ae. aegypti populations on the west coast do not follow the general trend, likely due to a recent and distinct invasion history. We argue that SFE provides a helpful albeit simplified model for the movement of Ae. aegypti across North America, with outlier populations warranting further investigation.     

The Phytogeography of the extinct angiosperm Nordenskioeldia (Trochodendraceae) and its response to climate changes

Elucidating the spatio-temporal distributions of terrestrial plants is a key for interpreting the origin of distribution patterns and the tempo of intercontinental disjunction. Nordenskioeldia was distributed in eastern Asia and North America from the Late Cretaceous to the Miocene. Its fossil record provides important information on former patterns of disjunction and dispersal in the Northern Hemisphere. New specimens from the Paleocene of China allow us to further extend the history of the group and provide the impetus to review its distribution in space and time. The comparative morphological survey on fossil Nordenskioeldia found in the Paleocene sediments in both eastern Asia and North America confirms that they belonged to the same morpho-species, which indicates a close floristic continuity between both continents due to land connection available during that time. The spatio-temporal distributions of Nordenskioeldia indicate that the taxon probably expanded eastward from eastern Asia into North America by the end of Early/Middle Maastrichtian, subsequently colonized Greenland, northeastern North America and Spitsbergen in the Early Paleocene, and finally became extinct in the Miocene. The fluctuations in its northern limits took place in response to climate changes: warming from the Paleocene to the Eocene, cooling during the Eocene–Oligocene and amelioration during the Late Oligocene–Mid-Miocene.     

Invasive alien plants in China: diversity and ecological insights

China’s current invasive alien plant species were analyzed with regard to their floristic status, biological attributes and invasion status elsewhere. Most of the 270 species identified were annuals, followed by perennial herbs. Woody perennials made only about 10% of the species. The invasives were comprised of 59 families, the largest being Asteraceae, Poaceae, and Brassicaceae. The genera with most invasive species were Amaranthus, Ipomoea, and Solanum. Most of the species originated from the New World, notably from South America. About one-third of the species were serious invaders of natural habitats in countries other than China. The proportion of invasive alien plants in province floras ranged from 0.5 to 3.8%, absolute numbers from nine to 117 species per province. Density of invasive species was correlated positively with native species density at provincial scale. The results demonstrate that in China invasive plants are present throughout the country, with a particularly high species richness in the Southeast. The ecological diversity of invasive plants suggests wide ranging impacts which need to be assessed.     

Paleogene fossil fruits of Stephania (Menispermaceae) from North America and East Asia

Stephania Loureiro is a large genus within Menispermaceae, with approximately 60 extant species naturally distributed in tropical to subtropical areas in Asia and Africa, and a few in Oceania. This genus possesses highly characteristic endocarps that facilitate identification of extant and fossil specimens. Here, we report some well-preserved fossil fruits of Stephania from North America and East Asia. The specimens indicate the endocarps were bony or woody with an obovate to obovate-rotund outline and a horseshoe-shaped locule. The endocarp length varies from 4.7 to 8.3 mm, and width from 3.7 to 7.0 mm. The endocarp has a clear foramen in the central area and is surrounded by a keel with ribs running along the dorsal surface. Only one lateral crest develops on each side of the endocarp. Two new species are recognized: Stephania wilfii Han & Manchester sp. nov. from the Paleocene to Eocene of Wyoming (USA), and Stephania jacquesii Han & Manchester sp. nov. disjunct between the late Eocene of Oregon (USA) and the late Oligocene of Guangxi Province (China). In addition, on the basis of more detailed morphological comparative analyses, we transfer the fossils formerly treated as Diploclisia auriformis (Hollick) Manchester from the early Eocene of London Clay, and the middle Eocene of Alaska and Oregon to Stephania auriformis (Hollick) Han & Manchester comb. nov. These fossil materials indicate a broader biogeographic distribution for the ancestors of extant Stephania lineages. This finding enhances our knowledge of the taxonomic and morphological diversity of Stephania and provides new evidence concerning its phytogeographic history.