西鄂尔多斯维管植物区系特征分析

 通过在西鄂尔多斯地区几年的植物标本采集以及参考前人对该地区植物名录的记载,对西鄂尔多斯地区野生维管植物种类组成、生活型、水分生态类型及植物区系地理成分进行了分析研究。结果表明:①西鄂尔多斯地区的野生维管植物共有64科、215属、433种;②植物的生活型以多年生草本为主,占52.66%,其他为乔木占0.69%、灌木占14.09%、半灌木占6.93%、一或二年生草本占24.25%、草质藤本占0.92%,类短命植物占0.46%;③植物的水分生态类型以旱生（包括强旱生、旱生和中旱生）为主,占49.42%,中生植物（包括旱中生、中生、湿中生）占47.58%,湿生植物占1.85%,水生植物仅占1.15%;④西鄂尔多斯地区植物区系地理成分组成复杂多样,在温带区系性质为主体的背景下,受欧亚草原区系、东亚森林区系、亚洲中部荒漠区系及古地中海区系的影响。     

毛乌素沙地低湿地维管植物区系特征

运用植物学及植物地理学方法,结合野外实地调查,对毛乌素沙地低湿地植物区系组成、地理成分、生活型及水分生态类群特征进行了分析研究。结果表明,低湿地共有维管植物59科182属323种,其中被子植物占总数的99.07%。单种科、寡种科和单种属、寡种属是低湿地植物区系的主体,是植物区系复杂性及物种多样性的主要来源,寡种属优势明显。中型科属和较大科属虽不占主体,但却往往是构成植物群落的建群种或为植物区系的代表成分,对植物区系的构成及植被的分布格局都有很大的影响。植物区系地理成分多样,温带分布型是低湿地植物区系地理成分的主要组成部分,低湿地植物具有典型的温带特征。低湿地草本植物占数量优势,草本植物以多年生为主,多年生草本植物对低湿地环境影响作用较为明显。低湿地植物地理成分及分布特征也说明气候、环境条件,植物种的生态幅度及其对环境的适应能力对植物地理分布具有决定性影响。     

Observations on the vegetation and vascular plants of Hopen

The vascular plant flora of the small arctic island of Hopen, located in the Barents Sea, was inventoried during a visit in the summer of 1982. Eighteen vascular plant species were observed and mapped, and the vegetation described.     

山西太岳山种子植物区系特征

调查的基础L，统计了太岳山种子植物有97科、316属、575种（含变种），分析了该区系的主要特征，即植物区系地理成分复杂，温带成分占优势；植物资源种类丰富，区系起源古老；植物区系具明显的过渡性；植被类型复杂，具明显的垂直分布．对该区野生经济植物进行了分类统计，为植物资源合理利用与生物多样性保护提供了基础资料穹科学依据．     

从秦岭蕨类植物区系地理成分论秦岭山地生态分界线的划分

依据2007~2008年野外实地调查以及相关文献资料,运用植物区系地理学和数量生态学方法,分析了秦岭蕨类植物区系的物种组成和地理分布特征,划分了秦岭蕨类植物的垂直带谱,并以此为基础探讨了秦岭山地生态分界线的划分,得出以下主要结论:(1)秦岭共有蕨类植物36科85属311种,优势科为鳞毛蕨科、蹄盖蕨科和水龙骨科,优势属为鳞毛蕨属和耳蕨属;在科属水平上,以热带成分占优势;而种的水平则以温带成分占绝对优势。(2)根据秦岭蕨类植物南北坡垂直带谱的对比分析,南坡海拔1000m左右应该是一条重要的生态分界线。(3)南坡1000m以下蕨类植物区系组成更接近亚热带区系,而其他地带则与温带蕨类植物区系更为接近,DCA排序很好地证明了此结果。综合来看,将南坡海拔1000m作为秦岭山地亚热带与暖温带的生态分界线较为科学。     

库姆塔格沙漠植物区系组成及地理成分

运用植物学及植物地理学方法,结合实地植被调查,对库姆塔格沙漠植物区系组成、地理成分、生活型及分布特征进行了分析研究。结果表明：库姆塔格沙漠区属于典型的荒漠植物区系,共有种子植物22科69属109种,其中被子植物占总数的98.13%。单种科、寡种科和单种属、寡种属是库姆塔格沙漠植物区系的主体,是植物区系复杂性及物种多样性的主要来源,寡种属优势明显。中型科属和较大科属虽不占主体,但却往往是构成植物群落的建群种或植物区系的代表成分,对植物区系的构成及植被的分布格局都有很大的影响。植物区系地理成分多样,温带分布和地中海分布是本区系地理成分的主要组成部分,区域植物具有典型的温带特征。受地形地貌、气候环境的影响,区域植被分布随地貌变化呈现出不同的分布格局,具有非地带性差异特征。库姆塔格沙漠草本植物占数量优势,木本植物以灌木为主,木本植物对区域环境影响作用较为明显。库姆塔格沙漠区植物地理成分及分布特征也说明气候、环境条件,植物种的生态幅度及其对环境的适应能力对植物地理分布的决定性影响。     

Patterns of alien plant invasions in northwestern Patagonia, Argentina

Invasive plant species are a growing concern in many regions of the world, yet little information is available on the effects of habitat type and distance to urban settlements on the ability of alien plants to become established. We studied plant communities from the arid steppes to the Andean forest within two national parks and surroundings, in northwestern Patagonia, Argentina. Alien and native vascular plant species were sampled using 90 × 100 m² plots and analyzed in relation to both climatic and environmental variables and distance to urban centres. We also compared life-forms of alien and native species. Precipitation and distance to an urban centre were important determinants of alien species community richness and composition, and shrubland sites had significantly more alien species than forest or steppe sites. Alien flora (15% of the species) was composed of a higher proportion of annuals and biennials than native flora. Our results suggest that precipitation, distance to source population, and anthropogenic disturbance influence the invasion process in this region, together with the availability of open niches. This work stresses the importance of monitoring invasive species in natural reserves, and of considering habitat types as well as idiosyncratic characteristics of the non-natives for developing management strategies.     

VASCULAR PLANTS OF MOUNTAIN TALUS SLOPES,MT. RAE AREA,ALBERTA, CANADA

The vascular flora of talus slopes in the Mt. Rae area, Canadian Rocky Mountain Front Ranges, is discussed in the context of edaphic and geomorphic conditions. Thirteen talus slopes were sampled systematically for the presence of vegetation, and vascular plants were identified to the species level. Such talus slopes are generally considered relatively sterile and too unstable for the development of distinctive flora. The presence of vegetation is usually taken as an indicator of slope stability. A total of 77 species with boreal and arctic affinities was identified. Most plants display growth forms suitable to the unstable and xeric talus substrate with Schroeter's Schuttstrecker and Schuttdecker forms being most common. Although areal coverage by plants is sparse, a large number of species with morphological characteristics suitable for the talus environment suggests that the presence of plants should not be regarded as an absolute indicator of slope stability. Rather, these plants may represent a long-term equilibrium assemblage characteristic of active talus slopes in a mountain environment.     

台湾地区种子植物区系的基本特征

本文通过对有关资料的统计分析，从区系的组成成分、地理成分、古老成分及特有成分等方面论述了台湾地区种子植物区系的基本特征，并简析了其形成的原因。     

官厅水库国家湿地公园维管植物多样性

2018年3月至2019年3月期间,在官厅水库国家湿地公园内,进行了野外植物调查,研究了维管植物的物种多样性、重要值和植物区系。研究结果显示,在官厅水库国家湿地公园内,共有维管植物318种,隶属61科191属;植物区系以温带成分为主;其中,绶草(Spiranthes sinensis)和野大豆(Glycine soja)为《中国国家重点保护野生植物名录》中的国家二级保护植物,黄芩(Scutellaria baicalensis)、宽叶香蒲(Typha latifolia)、黑三棱(Sparganium stoloniferum)和眼子菜(Potamogeton distinctus)为《河北省重点保护野生植物名录》中的河北省重点保护植物。在官厅水库国家湿地公园内的5处调查样地中,官厅水库西北岸浅水河漫滩-沼泽中植物群落的优势度指数、多样性指数和均匀度指数都相对最高。     

六盘山植物区系基本特征的初步分析

六盘山位于陕甘宁交接地区,属于半湿润气候向半干旱气候的过渡带,是黄土高原生物多样性最丰富的地区之一,有维管植物836种,隶属于93科,359属。本区属于泛北极植物区、中国-日本森林植物亚区、华北植物地区的黄土高原亚地区。全部种子植物可分为13个分布区类型和12个变型,以北温带分布类型为主,与其他植物区系联系广泛,但特有属较贫乏。六盘山与小陇山、太白山和中条山的属相似性系数较高,均达60%以上,表明几座山体处于相似的生物气候背景之下,地理隔离性不明显。与贺兰山的属相似性系数低于60%,因为贺兰山位于干旱的荒漠与半荒漠区,可能有地理隔离作用。     

新疆种子植物科的区系地理成分分析

对新疆种子植物区系及其科的组成和地理成分进行研究,结果表明：（1）新疆野生种子植物中科的优势现象很明显,种类超向于集中在少数科内。（2）科的地理成分方面,世界广布科占有很高的比例（35．0％）,说明新疆区系具有明显的过渡性;但各类温带分布科比例更大（52．0％）。（3）新疆区系的表征科有特殊性,如含有世界广布的藜科、十字花科、蓼科、石竹科等,这是与热带、亚热带区系的组成完全不同的;但其它表征科、优势科仍以温带科或主产温带的科为主。     

江西云山种子植物区系特点

本文在概要介绍江西云山种子植物区系科、属、种的分布类型成分的基础上,将该区系的特点归结为:1.热带性科、温带性种占优势,热带性属与温带性属并重;2.地理成分复杂,区系联系广泛;3.华夏种类丰富,特有成分多样;4.区系相当古老,残遗植物众多;5.该区系属华东区系的一部分,具有北亚热带向中亚热带过渡的特征。     

Human impact on the forests of Bermuda: the decline of endemic cedar and palmetto since 1609, recorded in the Holocene pollen record of Devonshire Marsh

The wreck of the Sea Venture on Bermuda reefs in 1609 initiated continuous habitation by humans on these islands. Colonization brought significant changes to the native and endemic flora of Bermuda. Original floral diversity was low, due to the effects of isolation and lack of previous anthropogenic influences. Two dominant endemic components of the flora, Bermuda cedar (Juniperus bermudiana) and Bermuda palmetto (Sabal bermudana), were extensively utilized by the colonists. Cedar was used for housing, furniture, shipbuilding and export, while the palmetto was used for roof thatch, basketry, food and drink. Exploitation of these species occurred to such extent that the General Laws of Bermuda included resolutions protecting them as early as 1622. Later, in the period between 1946 and 1951, two accidentally introduced scale insects eliminated 95% of the existing cedar population.While the flora and geography of upland habitats on Bermuda have been drastically modified by humans, the peat marsh basins have remained relatively unaffected. From the peats of one of these, Devonshire Marsh, a 9-m core was extracted for pollen analysis and to evaluate the potential for further study. The pollen record below 1.6 m indicated very little change in the native and endemic flora of Bermuda, but above that depth statistically significant changes in the relative abundances of pollen of Bermuda cedar and Bermuda palmetto are noted. Relative abundances of both species decreases significantly above this depth. This decrease is interpreted to represent the arrival of colonists and their impact on the cedar and palmetto populations. A second decrease in relative abundance of Bermuda cedar is recorded above 0.7 m. This reflects the scale infestation and decimation of the remaining cedar population. Coincident with decreases in cedar and palmetto are increases in relative abundance of Poaceae and Asteraceae, indicative of cleared land and the spread of weedy taxa. A radiocarbon date of 520±70 yr BP at a depth of 1.7 m and major changes in relative abundance of palynomorphs in proximity to the marsh surface allows their interpretation as a record of human impact on the endemic flora of Bermuda.This is the 19th in a series of papers published in this special AMQUA issue. These papers were presented at the 1994 meeting of the American Quaternary Association held 19–22 June, 1994, at the University of Minnesota, Minneapolis, Minnesota, USA. Dr Linda C. K. Shane served as guest editor for these papers.     

塔吉克斯坦种子植物区系分析

塔吉克斯坦区系位置特殊、物种独特丰富,研究其植物区系特点对于进一步全面了解中亚植物资源现状、起源及演化具有重要意义。通过文献搜集、野外调查和标本查阅,对塔吉克斯坦种子植物区系特点进行了分析。结果表明：塔吉克斯坦境内共有种子植物4 115种,隶属于110科864属,种子植物丰富、种类分布表现出多数种集中于少数科属中,同时单种及寡种科属多的两端分布的特点;植物区系主要表现为温带性质,但也受到热带植物区系的深远影响,区系成分复杂、过渡特征明显,特有属少。特有成分在种级水平上分化明显,种子植物区系性质表现出与所处自然地理条件的一致性。     

On the Origin of the Strand Flat

One of the most fruitful problems to Scandinavian plant geography has been that of the origin of the Scandinavian alpine and arctic flora. A long time after the discovery of the Ice Ages in Northern Europe, the supposition was held that all plant life in Scandinavia was destroyed during the last Ice Age. This was the “tabula rasa” theory. According to this theory all plant life should have immigrated into Scandinavia after the last Ice Age. This also applied to the alpine and arctic element in the flora of Scandinavia. This element should have immigrated from areas outside the maximum glaciation in Central and Eastern Europe. The Scandinavian arctic-alpine flora is hence expected to be a province of the Middle or Eastern European flora.

This is not the fact. The Scandinavian alpine flora contains an important and even dominating element of species with their relatives on the western side of the Atlantic ocean. These species could hardly have their origin in Central and Eastern Europe.     

西藏阿里西部地区种子植物区系研究

基于路线调查和样地调查资料,鉴定记录到西藏阿里西部地区共有种子植物319种,隶属于53科159属。其中,裸子植物1科1属2种,被子植物52科158属317种,表明该地区植物种类贫乏。种子植物的区系成分复杂,划分为5个科分布区类型和9个属分布区类型,其中温带成分分布占绝对优势:温带科16科,占总科数的72.73%,温带属99属,占总属数的77.34%,说明本区系具有明显的温带性质。而热带成分仅有几个科属作为代表,表明本区系在发生发展过程中曾经历过与热带相联系的历史渊源。此外,特有性程度极低,没有中国特有科和特有属分布,证实了本区系植物的年轻性及其较短的演化发展历史。     

伏牛山和鸡公山自然保护区植物区系比较

比较研究了河南省内伏牛山和鸡公山两个自然保护区的植物区系,并计算了两地植物相似性系数。研究发现两地植物区系具有一定的相似性,但也存在一定的差异。伏牛山的植物区系整体上的过渡性更强,与华中区和华北区的联系比较紧密,既有热带、亚热带分布种,北温带分布种也占有一定的地位。鸡公山更趋近于北亚热带植物区系。     

浙江开化山区森林区系的地理成分研究

开化山区面积占总面积的８８％．是浙江植物种类最丰富的地区，有野生木本植物８３２种，隶属于９５科２７２属．在对森林区系统计和分析的基础上，着重研究了地理成分，认为它们具有下列特征：１．木本植物种类非常丰富；２．古老、孑造和珍稀濒危植物较多；３．区系地理成分复杂，与世界各地植物区系有广泛联系；４．２７０个属可划分为１４个类型（包含１２个变型）；５．温带成分占优势．     

Germination associated with season and sunlight for Tamaulipan thornscrub plants in north-eastern Mexico

Seed germination was investigated for 47 herbaceous and woody species, representative of the Tamaulipan thornscrub flora of north-eastern Mexico. More than half of the species had similar germination under spring and autumn conditions, 17 species showed a higher germination percentage under autumn rain conditions. No species had more seeds germinating under spring rain conditions. Germination season response was independent of plant habit, seed size and dispersal syndrome. Sixteen of the species germinated less under the moderate shade of thornscrub canopy than under direct sunlight, and more than half of the species had similar germination under shade and direct sunlight. Germination in autumn, and away from the root competition of thornscrub, may reflect the importance of soil drought in mortality of young seedlings.