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The development or adaptation radiation of angiosperms has been closely related to the paleoclimate and paleoenvironment. Several environmental factors, influencing each other, have affected the evolution or development of angiosperms, which falls into different stages. The lines between these stages are not consistent with the traditional geological ages. Floristic regionalization might be better based on the stages of the development. Angiosperms have become important or dominant elements in the flora since the middle and late period of the Late Cretaceous. The development of angiosperms may be divided into four stages: (1) Initial stage: The angiosperms were not yet well established during the Early Cretaceous. The number of species and individuals was limited, the leaf small, mostly with entire margine, irregular venation and poor differentiation of venation; (2) Flourished stage: The angiosperms increased dramatically and became abundant. The leaf was larger with more regular venation and the differentiation of venation was remarkable. The percentage of angiosperms was from 40%-60% in the flora, and eventually arose, becoming predominant, with important families well presented. This was probably from the Late Cretaceous to the Early Tertiary; (3) Herbs-Flourished stage: Some of woody plants were extinct, while herbs greatly increased, because of the changes in climate, sea level and mountain uplift during the Neogene period; (4)Quaternary stage: The mountain glacier in China, influenced by global glacial-interglacial alternation due to the climatic fluctuation, advanced and regressed during the Quaternary. The climatic fluctuation apparently affected the distribution of plants. But the components of the flora were similar to or slightly different from the features of the present one. The aim of the present paper is to discuss the floristic regions at the second and third stages. The Late Cretaceous-Early Tertiary stage: A. The Late Cretaceous-Paleogene flora of northern China 1. Warm-temperate to subtropical deciduous broad-leaved and conifer forests in North and Northeastern China 2. Dry subtropical flora of Northwestern and Central China B. Southern China Late Cretaceous-Paleogene flora 3. Deciduous and evergreen forests with coniferous elements in the subtropical coastal region of east China 4. Evergreen forests of South China 5. Evergreen forests of lower mountains in the Tethys The Neogene stage-Herbs-flourished stage: 1. Temperate forests and grasslands to semidesert-desert floras of northwestern China; 2. Warm temperate deciduous forests of north and northeastern China; 3. Warm temperate to subtropical deciduous and evergreen forests of central and east China; 4. Evergreen forests of the subtropical and tropics mangrove vegetation of south China; 5. Subtropical evergreen and deciduous forests on the Yunnan and Xizang plateau.  相似文献   

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皖西霍山县白马尖植物区系和植被   总被引:4,自引:0,他引:4       下载免费PDF全文
本文论述了北亚热带典型地段——大别山主峰白马尖的植被和植物区系的特点,提出白马尖地区是一“生物避难所”。与纬度相近地区的比较研究,结果表明,海拔1000米以上的山地,植被类型和植物区系成份与皖南黄山、浙北天目山较一致,而低海拔地区与江苏的宜溧山区相似,特别是常绿阔叶树的属、种极为一致。值得指出的是耐寒常绿阔叶林类型的发现,为北亚热带植被地带的概念增添了新内容。文中对原圈定佛子岭水库库区周围为水源涵养林自然保护区认为不妥,将白马尖主峰整个集水区包括在内,才是完善的。  相似文献   

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广东石门台自然保护区石灰岩地区植物区系和植被   总被引:7,自引:1,他引:7  
分析了广东英德石门台自然保护区石灰岩地区森林植被的植物种类组成。外貌结构,群落类型和分布状况及石灰岩植物的主要适应特点,并对如何保护和恢复石类岩地区的森林植被提出了建议。  相似文献   

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The home of Nigeria's renowned Marxist anthropologist, Ikenna Nzimiro, and of the country's ``first lady of letters,' Flora Nwapa, is Oguta, a sprawling commercial centre situated on Oguta Lake near the confluence of the rivers Niger and Urashi. Both authors have described their home town in their own diverging perspectives. While Nzimiro's account focused on the town's political organization and questions of state formation and authority, Flora Nwapa was a novelist concerned primarily with women's issues. She engaged her home town's custom and religious beliefs centring on the pre-eminent lake goddess, Ogbuide, in her quest to champion womanhood. This paper examines how the novelist took certain artistic liberties and critically deconstructed local custom in her cause to promote women. While Nwapa's primary concern was women's reproductive rights and welfare, she also cherished Oguta culture, voiced her critique with caution, and was increasingly critical of foreign intrusions.  相似文献   

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自然保护地通常是重要的生态敏感区域,具有十分重要的生态和社会经济价值,因此维持自然状况,避免人为干扰是日常管理的基本要求.借助遥感手段,快速识别人为扰动引起的景观变化,是加强保护地管理的有效手段.以升金湖国家级自然保护区为研究对象,基于RS和GIS空间分析等技术方法,利用人为干扰度模型,并结合特定人类活动干扰类型的变化...  相似文献   

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镜泊湖自然保护区种子植物区系的研究   总被引:4,自引:1,他引:3  
经野外调查及资料统计,已知镜泊湖自然保护区有野生种子植物101科395属809种,其中裸子植物3科7属12种,被子植物98科388属797种。本区地理成分复杂。以温带成分占绝对优势。温带分布属287属。占总属数的85.42%;温带分布种647种。占总种数82.40%,其中国-日本分布和东北分布有292种。占总种数的37.2%。是本区温带地理成分的核心。  相似文献   

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哈纳斯自然保护区植被特点及植物区系形成的探讨   总被引:1,自引:0,他引:1  
哈纳斯自然保护区的植被充分反映了欧洲——西伯利亚区系成分的特色。山地针叶林带与天山相比显著下降,为阴暗泰加林类型。植被类型丰富多样,与天山的植被特点迥然不同。本区植物区系形成于第四纪。其区系组成以温带成分为主,并含有少量的古地中海成分。以本土发生的安加拉区系成分为主体;发源于华夏地台的亚洲温带成分渗透至本区;残存的古地中海成分有小部分通过相邻地区向本区渗入  相似文献   

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据调查,江西遂川五斗江国家湿地公园共有野生维管束植物108科286属450种,以禾本科Gramineae、菊科Compositae等为优势科,悬钩子属Rubus为优势属。共有13个植物区系类型,以泛热带分布、世界广布和温带分布的比例最大,属的热温比(R/T值)为1.10,区系性质表现为隐域性和地带性共存的特点。有珍稀濒危植物21种,尤其是樟树Cinnamomum camphora和闽楠Phoebe bournei分布广泛,并有大量古树。植被类型可分为5个植被型组12个植被型58个群系,为典型的河岸带湿地植被。  相似文献   

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