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1.
长江上游滇西北地区植物区系组成及物种多样性   总被引:1,自引:0,他引:1  
长江上游滇西北地区是全球重要的生物多样性热点地区之一,也是长江流域重要的生态屏障。利用最新的文献数据,结合过去5 a的野外考察成果,分析了滇西北地区的植物区系组成及其物种多样性。研究结果表明:滇西北地区拥有种子植物6 559种,分属于205科,1 281属。滇西北地区以04%的国土面积,拥有我国种子植物科数的74%,属数的41%和物种数的20%。同时也以10%的土地面积,拥有云南地区种子植物科数的77%,属数的55%和物种数的43%。在热带区系组成方面,比重较大的分布区类型为泛热带分布(165%)和热带亚洲分布(122%);在温带区系方面,北温带分布和东亚分布所占比重比较高,分别为193%和145%。热带区系成分与温带区系成分所占的比重非常接近,分别为47%和53%,表现出强烈的区系过渡性,这可能与地层抬升、板块漂移和温性植物类群的迁入有关。温带区系比重略高于热带区系,说明该区域的植物区系具有一定的温凉性质,这与滇西北地区相对温凉的气候环境是一致的。科的分化强度为63;属的分化强度为51。研究区域内丰富的植物多样性与其复杂的生境、强烈的区系过渡性和区系分化是一致的。滇西北地区可能是验证、发展各种生物多样性假说的理想场所。因此,滇西北地区的植物多样性不仅值得人们关注和保护,而且也值得研究和探索。与滇东北的药山自然保护区相比,滇西北地区拥有更高比重的热带亚洲成分,这可能与古南大陆的“掸邦 马来亚”板块的位移和旋转有关。滇西北地区与滇西南的铜壁关自然保护区在植物区系高级分区和系统进化的起源上具有一定的联系,在一定程度上证实了“田中线”的真实存在。联系滇西北地区植物区系与铜壁关自然保护区植物区系的节点可能是研究区域内的独龙江地区.  相似文献   

2.
Trends in the anthropogenic transformation of flora in the city of Astrakhan and its environs over the past 100 years are discussed. In general, the process of flora synanthropization is observed, with natural aboriginal plant communities being replaced by anthropogenically altered communities.  相似文献   

3.
Cities are areas of increased diversity of species in the taiga zone. The aboriginal fraction of Karelian flora is a stable natural system whose main characteristics are preserved in the urban flora. The adventive fraction, which is a dynamic component of the flora, has not been completely formed in the cities, as well as in eastern Fennoscandia as a whole. It has become substantially richer during the past 20–25 years. Cities of the taiga zone may serve as objects for monitoring the anthropogenic processes of flora transformation in the North.  相似文献   

4.
崇明岛共有区系植物55科157属198种,区系组成复杂,地理成分多样,涵盖全部15个分布区类型,具有明显的热带-温带过渡性质,落叶树种占木本植物种类的90.5%,属于北亚热带常绿落叶阔叶混交林地带。群落外貌及属的相似性系数分析表明,崇明岛植物区系更接近江苏宜兴,而与临近的大金山岛和佘山差别略大。此外,岛上还有栽培植物和外来植物共235种,其中蔷薇科、菊科、禾本科、豆科、木犀科等科的种类较丰富,以加拿大一枝黄花、臭荠、刺果毛莨、一年蓬、空心莲子草、大米草、互花米草等对当地植被资源和生态系统的影响最大。崇明岛植物群落结构单一,缺乏灌木层,草本层多为广布杂草,其植被资源可以根据功能划分为江防海防林、湿地植被、道路绿化带、庭院景观林、游憩林、大田作物及经济林、水源涵养林等7大类,其中江防海防林及湿地植被是崇明岛植被生态系统的关键成分。提供了崇明岛新纪录野生及外来种子植物名录。  相似文献   

5.
Parameters characterizing the activity of species in altitudinal zonal elements of the flora have been analyzed in the northern Baikal region. The results provide evidence for the weakening status of xerophilic species in the cenoflora of hemiboreal light coniferous forests of the class Rhytidio-Laricetea, which form the lower part of the forest belt bordering the steppe. This fact indicates that climate on the slopes of mountain ridges is becoming more humid. The increase in humidity may be explained by both progressing degradation of permafrost and increasing precipitation. On the other hand, no significant change has been observed in the cenoflora of mountain taiga forests of the class Vaccinio-Piceetea, which form the upper part of the forest belt.  相似文献   

6.
三峡库区古大树种资源及其保护对策   总被引:3,自引:0,他引:3  
长江三峡工程库区,蕴藏着丰富的古大树种资源,约有5000余株。作者从中挑选了树龄较大者195株作为库区重点保护对象,并提出相应的保护对策措施。  相似文献   

7.
In the course of floristic studies in suburban forests near the city of Ivanovo, 206 species of vascular plants have been recorded, including 39 invasive species (18.9%). Information on specific features of distribution and activity of introduced species growing feral and accidental weeds in different forest types is presented. The most aggressive species are distinguished. Factors responsible for the invasion of alien species to forest cenoses and main tendencies in their dynamics are discussed.  相似文献   

8.
三峡库区香溪河流域河岸带种子植物区系研究   总被引:6,自引:1,他引:5  
根据详细的植物群落调查资料,对三峡库区香溪河流域河岸带种子植物区系进行了研究。结果表明:河岸带维管束种类在科级水平上占神农架的65.8%,在属级水平上占47.3%,在种级水平上占26.7%。河岸带植物区系的性质为温带特性,与神农架地区种子植物属的性质相一致。河岸带这一独特自然景观的植物区系在整个区域自然景观中具有相当的代表性。在香溪河流域河岸带中,维管束植物种类较丰富,分布着大量的珍稀濒危植物种类,表明河岸带在生物多样性保护中具有重要的作用。  相似文献   

9.
10.
A method for estimating floristic diversity at the species, genus, and family levels and the taxonomic structure of the flora of protected natural areas is proposed. The method is illustrated using the example of three nature reserves located in the Northern, Middle, and Southern Urals. The dependence of the characteristics of the regional floras on their positions in the system of botanical–geographic zones, the size of the protected area, and other factors have been studied in these reserves. The proportion of endemic plants and the degree of flora synanthropization have been determined.  相似文献   

11.
The size of Larus schistisagus nesting colony on Shelikan Island (8 ha in area) has increased from 2000 to 6000 pairs over 18 years. Today, this is the largest colony in the Sea of Okhotsk. The growth of the bird population has entailed catastrophic deterioration of the plant cover accompanied by a decrease in the species diversity of vascular plants: more than one-third of plant species recorded on the island in 1986 have already disappeared, and the establishment of several new plant species cannot compensate for this loss. If the size of the colony increases further, woody vegetation will fully deteriorate and only a thinned herbaceous layer consisting of 15–20 most resistant species will remain on the island.  相似文献   

12.
Quantitative methods have been applied to the study of floristic structure and diversity in Samarskaya Luka. The results show that Samarskaya Luka is a floristically heterogeneous area in which six elementary floras can be distinguished. This area has been assessed as a floristically autonomous formation, and its floristic representativeness was estimated.  相似文献   

13.
Using the example of Southern Ural forests, it is shown that the Braun-Blanquet method is promising for estimating the efficiency of the system of specially protected natural areas (SPNAs) and drawing up guidelines for its further development. In particular, evidence is provided that forests of the unions Aconito-Piceion and Lathyro-Quercion are protected quite insufficiently. Proposals concerning organization of new SPNAs are formulated.  相似文献   

14.
15.
Studies on the vegetation and soil complexes in areas of the Kolyma River basin disturbed by mining, in the northeast of the Chukchi Peninsula, have been performed to reveal trends in natural restorative processes in posttechnogenic landscapes. Data on the flora, phytomass stock, chemical composition of plants pioneering in the overgrowing of disturbed areas, and physicochemical properties of soils and technogenic eluvia have been obtained. The results have shown that plant cover restoration in disturbed areas depends primarily on the type (genesis) of technogenic substrates, the content of fine earth in the surface layer, and the distance from natural plant complexes that serve as a source of seeds coming to the disturbed area.  相似文献   

16.
Latin America comprehends notable variations in terms of natural environment, availability of natural resources, living standards, and demographic patterns. Latin America is a mosaic of cultures, post- and pre-Columbian. The rich variety of life forms discovered and described by chroniclers and traveling naturalists in the Neotropics contributed to the proposal, in mid-XVIIIth century, of a new system of classification and a scientific code of nomenclature for all organisms. Biodiversity was, for many centuries, a source of resources to be exploited in natura. In scientific circles, its inventory became the domain of taxonomists. But modern technology showed how important the miriad of life forms really are as sources of chemical molecules to be engineered as drugs and reassembled as novel manufactured products. We are on the brink of a new agricultural and medical revolution, thanks to the techniques of genetic engineering, which will lead eventually to the elimination of hunger and malnutrition.In this essay, the Brazilian environmental and social heterogeneity will serve as an example to illustrate some key points, which have influenced sustainability policies. The Amazon deforestation and indigenous knowledge (IK), subjects often associated with areas of high biodiversity, are usually the focus of environmental debates. The importance of IK in integrating development, reducing poverty and sustainability are considered together with the intellectual property rights of native populations.In the World Summit on Sustainable Development (WSSD) Implementation Plan, a few paragraphs were dedicated to Latin America, because of the pre-existing Action Platform on the Road to Johannesburg 2002, approved in Rio de Janeiro in October 2001. This paper calls attention to the need to draw up specific environmental policies for a region which shows an extremely high cultural and biological diversity, associated with a high availability of forests and water, among other resources.  相似文献   

17.
湘鄂赣地理位置优越,农业资源丰富,稻谷、茶叶、麻类、棉花、油料、柑桔和淡水产品、禽蛋、肉类等在我国居有重要的地位,因此,大力发展三省农业生产,对我国人民实现小康生活具有战略意义。今后,要加速专业化区域化进程。我们找出生产潜力所在:改造低产田、低产园、低产水面;开发“三高”技术;开垦荒地、荒山、荒水;适当提高复种指数。通过建设,三省主要农产品将自给有余,还可满足国内外市场的需要。努力方向:高效农业开发——综合农业开发,吨粮田开发,玉米带开发,饲料稻开发,山区开发;合理布局农业生产;深化农业商品基地建设,发展综合利用,搞活商品流通;全面提高农业现代化水平,加强农业社会服务体系。  相似文献   

18.
Integration of indigenous knowledge and ethnoscientific approaches into contemporary frameworks for conservation and sustainable management of natural resources will become increasingly important in policies on an international and national level, both in countries that are industrialised and those that have a developing status. We set the scene on how this can be done by exploring the key conditions and dimensions of a dialogue between ȁ8ontologiesȁ9 and the roles, which ethnosciences could play in this process. First, the roles of ethnosciences in the context of sustainable development were analysed, placing emphasis on the implications arising when western sciences aspire to relate to indigenous forms of␣knowledge. Secondly, the contributions of ethnosciences to such an ȁ8inter- ontological dialogueȁ9 were explored, based on an ethnoecological study of the encounter of sciences and indigenous knowledge in the Andes of Bolivia, and reviewed experiences from mangrove systems in Kenya, India and Sri Lanka, and from case-studies in other ecosystems world-wide, incl. Australia, Burkina Faso, Ecuador, Ethiopia, Guatemala, Indonesia, Nepal, Niger, Philippines, Senegal, South-Africa and Tanzania.  相似文献   

19.
We review studies of the effects of low ambient ozone concentrations on morbidity that found a negative coefficient for ozone concentration. We call this a Paradoxical Ozone Association (POA). All studies were in regions with methyl ether in gasoline. All but one study carefully controlled for the effects of other criterion pollutants, so the phenomenon cannot be attributed to them. One was in southern California in mid-summer when ozone levels are highest. Because ozone is created by sunlight, the most plausible explanation for a POA would be an ambient pollutant that is rapidly destroyed by sunlight, such as methyl nitrite (MN). A previously published model of engine exhaust chemistry suggested methyl ether in the fuel will create MN in the exhaust. MN is known to be highly toxic, and closely related alkyl nitrites are known to induce respiratory sensitivity in humans. Support for the interpretation comes from many studies, including three linking asthma symptoms to methyl tertiary butyl ether (MTBE) and the observation that a POA has not been seen in regions without ether in gasoline. We also note that studies in southern California show a historical trend from more significant to less significant ozone-health associations. The timing of those changes is consistent with the known timing of the introduction of gasoline oxygenated with MTBE in that region.  相似文献   

20.
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