【作者】 李登武；

【导师】 张文辉；

【作者基本信息】 西北农林科技大学 ， 植物学， 2008， 博士

【摘要】 本文首次以黄土高原地区植物区系的重要组成部分——陕北黄土高原维管植物区系作为研究对象,在广泛深入调查和参考大量文献的基础上,采用植物区系地理学、生物多样性保护与利用和植物生态学等相关学科的理论与方法,从植物区系组成、区系性质、特有现象、替代现象、地理联系、区系的起源与演化、区系分区及空间分异特征等方面对本区植物区系进行了深入研究,同时对本区典型流域的植物生物多样性、典型植物群落区系进行了研究,另外,对本区保护植物、资源植物进行了研究,并提出了保护和可持续利用对策。主要结果如下:1.植物区系分类群组成(1)种类较丰富,种系密度较大陕北黄土高原有野生维管植物140科574属1 413种(包括种下等级),科、数、种分别占黄土高原地区总科数71.3%、总属数的62.4%、总种数的41.4%。其中,蕨类植物有17科32属63种,种子植物有123科542属1350种。维管植物种系密度为1.52/100km2。(2)优势现象较明显,表征类群较丰富本区植物区系的优势科有26科,表征科有9科;优势属有23属,表征属有24属,以及较多的植被优势种和表征种。(3)单种属和寡种属较丰富陕北黄土高原种子植物区系中有单种(单型)属30属,有寡种(少型)属45属,这些属的生活型以草本植物为主,地理成分以东亚、古地中海、旧世界温带和中国特有成分为主。2.植物的生活型和生态类型多样生活型包括了乔木、灌木、草本(包括一年生、二年生和多年生草本)、藤本植物均有,其中以多年生草本植物占绝对优势。生态类型包括了水生、湿生、湿中生、中生、旱中生、中旱生、旱生植物,其中以中生植物为主。3.植物区系地理成分组成特点与性质(1)地理成分较复杂多样,地理联系较广泛;(2)温带性质显著,具有明显的过渡性。本区植物区系在地理上和发生上受到多方面的影响和渗透,区系成分较丰富,呈现出多种成分汇集,相互渗透,交错混杂现象,具有明显过渡性特征;(3)热带地区植物区系对本区有一定的影响,表明本区植物区系与热带地区的渊源关系。4.植物区系的特有现象和替代现象(1)本区无中国特有科,有4个东亚特有科,大多为东亚特有的孑遗类群;中国特有属贫乏,无本地特有属;中国特有种较丰富,本地特有种贫乏。(2)本区植物南北梯度变化明显,有些植物呈现出明显的地理替代现象。5.植物区系起源古老,并兼有年轻的成分。6.与其它地区植物区系的关系(1)陕北黄土高原与其它地区的R/T值(热带性质属与温带性质属的比例)比较,总体上基本反映了各自所处的生态地理环境及差异性。(2)与邻近地区植物区系的比较,结果显示,本区植物区系与河北山地、北京山地联系密切,与内蒙古、山西、宁夏也有一定联系。(3)与我国各大区域比较,结果显示,陕北黄土高原植物区系(尤其南部)与华北植物区系联系密切,本区北部植物区系与蒙古草原植物区系的联系密切,本区关山-黄龙山植物小区与秦岭北坡植物区系的关系较密切,与西南、华中、华东、东北地区植物区系有一定的联系。7.植物区系的演变和来源根据古植物学资料及与现代植物区系的对比分析对本区植物区系的演变和来源进行了研究,文中论述了自白垩纪以来各时期陕北黄土高原植物区系的演变发展过程,对陕北黄土高原植物区系的演变和现代与新生代孢粉植物群的比较,认为本区植物区系主要来源于4个方面:(1)起源于本地及邻近地区晚白垩纪-早第三纪植物群,一些草本植物和湿生植物主要发生于晚第三纪,耐寒和耐旱的种类主要发生于第四纪;(2)来源于地中海区-中亚和欧亚草原;(3)来源于东北亚、西伯利亚温-寒地区;(4)来源于我国西南、西北、华北及秦岭、华中地区。8.植物区系分区及空间分异特征(1)陕北黄土高原植物区系划分为2个植物省,即陕北北部植物省和陕北南部植物省,4个植物小区,即长城沿线风沙草原植物小区、陕北黄土丘陵沟壑灌木草原植物小区、子午岭-崂山植物小区和黄龙山-关山植物小区。(2)陕北黄土高原植物空间分异明显,4小区的植物种类丰富度具有明显的区域差异,以黄龙山-关山植物小区最丰富,最贫乏的是长城沿线风沙草原植物小区。(3)植物区系种系发育性比较陕北黄土高原南部比陕北黄土高原北部植物属、种分化较强烈。4个小区比较,结果表明,黄龙山-关山植物小区植物属、种分化强烈,长城沿线风沙草原植物小区属、种分化较弱。9.典型流域的植物生物多样性以封禁30多年的纸坊沟流域与邻近的县南沟流域(近年才封禁)相比较进行了研究,主要结果为:(1)两流域在植物种类组成上差异较小;(2)纸坊沟流域植物群落不仅类型多、大部分群落所占面积较大,而且以中生群落为主,相反县南沟流域植物群落不仅类型少、大部分群落所占面积小甚至有些中生群落即将退出该流域,而且以旱生群落为主;(3)纸坊沟流域主要群落的的建群种的高度、多度(丛(株)/m2)和盖度均高于或多于县南沟流域,差异显著;(4)纸坊沟流域主要群落中中生植物占有较高的比例,旱生植物占的比例小;(5)同一群落,纸坊沟流域与县南沟流域相比较,其群落中矮高位芽植物、地上芽植物、地面芽植物、层间植物等占有较高比例,而地面芽植物、一年生草本等占的比例较小;(6)同一群落相比较,一般来说,纸坊沟流域植物群落中物种丰富度、多样性指数和均匀度指数均比县南沟流域群落中的高。10.典型植物群落区系对陕北黄土高原和秦岭区辽东栎群落植物区系进行了比较研究,结果表明,陕北黄土高原辽东栎群落植物区系共有27科42属51种,秦岭北坡辽东栎群落共有31科60属67种。物种组成丰富性不及秦岭区,层次和层片结构较简单,两地辽东栎群落区系相似性不高,这主要是由两地该群落所处的生境条件所决定的。属和种的区系成分分析表明,两地辽东栎群落的区系性质是温带性质,两地该群落中国特有种中与华北共有种较多,与西南、华中、华东、东北等地区的共有种较少。11.珍稀濒危植物(1)珍稀濒危植物较丰富。陕北黄土高原有珍稀濒危植物75种,隶属于44科63属,其中,有国家级保护植物35种,省级保护植物7种,陕北黄土高原区区级保护植物33种。濒危等级划分为濒危(EN)、易危(VU)和近危(NT)3个等级,其中濒危的有15种,易危的有20种,近危的有40种;保护级别划分为一、二、三级3个保护级别,其中本区有一级保护植物39种,二级保护植物17种,三级保护植物19种。(2)本区保护植物所属属的地理成分以北温带、旧世界温带、东亚和中国特有成分为主,其中北温带成分占绝对优势;保护植物种的地理成分以中国特有、温带亚洲和东亚成分为主,其中中国特有成分占绝对优势,中国特有种中以华北、陕北黄土高原特有和西南-华中-华北成分为主。12.资源植物丰富,本区资源植物约有950种,根据其用途可分为14个类型。更多还原

【Abstract】 The vascular flora of the Loess Plateau of Northern Shaanxi Province (LPNS), one of the important components of Loess Plateau flora, was first analyzed as a whole object. Based on the great scale investigation and a large amount of references, adopting the theories and methods of the related disciplines like Floristic Geography, Biodiversity Protection and Utilization, Plant Ecology, etc., this paper studied the flora in the LPNS, including the floristic composition, characteristics, endemism, substitute phenomenon, geographical correlations, origination, evolution and development, floristic zoning and spatial distribution characteristic, plant biodiversity of typical valleys, flora of typical plant communities, protective plants and resources plants, and put forward measures for protection and sustainable development. The main achievements are summarized as follows:1.The characteristics of the floristic composition(1) The species of this area are comparatively rich and the species density high. There are 1 413 species (including infraspecies taxon) of vascular plants belonging to 140 families and 572 genera in the LPNS. The family, genus and species number of this region account for respectively 71.3%, 62.4%, 41.4% of that of the Loess Plateau. There are 63 species of fern belonging to 32 genera in17 families, and 1 350 species of seed plants belonging to 542 genera in 123 families. The species density of vascular plants is 1.52 species /100km2.(2) The dominance of vascular flora in the LPNS is comparatively strong, and the characteristic (or typical) taxa are comparatively rich. There are 26 dominant families, 23 dominant genera, 9 characteristic families, 24 characteristic genera, and a larger number of dominant or characteristic species.(3) The mono-species or minor-species genera are comparatively rich. There are 30 mono-species and 45 minor-species genera of the flora in the Loess Plateau of Northern Shaanxi Province. The life forms of these genera are mostly herbage, the areal types aremainly East Asia, Ancient Mediterranean, Old World Temperate and Endemic to China.2.The life forms and ecological types of the seed plants are various, with life forms including arbor, shrubbery, herbage (including the annual, biennial and perennial), liana etc. and the perennial herbage plays a dominant role. The ecological types include the aquatic, the hygrophyte, the Hygro- mesophyte, the Mesophyte, the Xero- mesophyte, the Meso-xerophyte and the Xerophyte and the mesophyte plants play a dominant role.3.About the characteristics of the floristic areal types.(1) The floristic elements are comparatively complicated and diverse and are extensively related to other areas.(2) The flora features a clear transitional and temperate character. The flora of LPNS is influenced and penetrated, geographically and genetically, in many aspects. Therefore, it has developed rich floristic elements, with distinct aggregation, penetration and mixture to show its strong transitional features.(3) Tropic flora affect to a certainty on the LPNS’s flora, and indicate the relation of origin of the LPNS’s flora with tropic area.4.The endemism and substitute phenomenon of the flora(1) There aren’t the families endemic to China in this region. But there are 4 families endemic to East Asia, mostly relic taxa. The genera endemic to China and the species endemic to Loess Plateau of Northern Shaanxi Province are comparatively poor, but the species endemic to China are rich.(2) The gradient change of plants from south to north of the area is outstanding, and some plants take clearly on geographical substitute phenomenon.5.The flora has not only an ancient origin, but also younger elements6.Relationship to the flora of other areas(1) The comparison of R/T value (the proportion of tropic genera to temperate genera) between LPNS and other areas reflects the ecological features and differences of the locations.(2) The flora of LPNS is found to be closely relation to the flora of the mountainous regions in Hebei and Beijing, and is also somehow related to the flora of Inner Mongolia, Shanxi and Ningxia.(3) On a larger scale, the flora of LPNS (especially South LPNS) is closely related to North China. The flora of North LPNS is very closely related to Mongolia grassland while the flora of the district of Huanglong Mt. and Guan Mt. is closely related to North slope of Qinling Mts., and is somehow related to Southwest China, Central China, East China and Northeast China.7.Sources and evolution of the floraAfter a comparative analysis of the paleobotany documents and present flora of the Loess Plateau of Northern Shaanxi Province (LPNS), the evolution and sources of LPNS’s flora are studied. The evolution of flora over all the stages since the Cretaceous period are discussed. From the flora evolution and the spore and pollen comparison between the modern and the Cenozoic period, it is believed that the flora of LPNS can be dated back to four major sources:(1) the local and neighbouring flora in the late Cretaeous period and Paleogene, with some herbaceous plants and hygrophytes originating in the Neogene and the hardy and drought enduring plants in the Quaternary period.(2) the Mediterranean, Central Asia and the Eurasian Steppe.(3) the Northeast Asia, the temperate and cold area of Siberia.(4) the Southwest China, Northwest China, North China, and the Qinling Mts. and Central China.8.The floristic zoning and spatial distribution(1) The flora of the area is divided into 2 plant provinces, namely North Plant Province of the LPNS and South Plant Province of the LPNS, and 4 districts: a. the grassland district of the sandy and windy area along the Great Wall; b. the shrubbery and grassland district in the loess hilly and gully area of the LPNS; c. the district of Ziwuling Mts. and Lao Mt.; d. the district of Huanglong Mt. and Guan Mt..(2) The plants of the LPNS features clear difference of spatial distribution, the richness of plants species of the 4 districts is obviously different. The district of Mt. Huanglong and Mt. Guan is richest, while the grassland district of the sandy and windy area along the Great Wall is the poorest.(3) Comparison of the flora species development. The differentiation of plant genera and species in the south LPNS is comparatively intense compared with North of LPNS. The differentiation comparison of plant genera and species of the 4 districts finds that the district of Huanglong Mt. and Guan Mt. is more intense, while the grassland district of the sandy and windy area along the Great Wall is comparatively low.9.The plant biodiversity of typical valleysThe Zhifanggou valley which was enclosed over 30 years ago was compared with Xiannangou valley enclosed in recent years in terms of the flora, life forms, ecological types, diversity of vegetation types, quantitative index of main plant community and species diversity of main plant community, etc.. The result are as follows: (1) the floristic species components of both the valleys are hardly different. (2) the plants communities of Zhifanggou Valley are not only diverse, but also extensively distributed and mostly composed of mesophyte communities. In contrast, the community number of Xiannangou Valley is small and most of the communities grow within a limited area. This valley is composed mainly of Xerophyte plants. some mesophytes are even disappearing from this valley.(3) The edificato height, richness (piece/m2) and coverage of the major communities in Zhifanggou are obviously higher than that of Xiannangou.(4) the mesophytes account for a higher proportion in the major communities of Zhifanggou and the xerophytes account for a smaller proportion.(5) in a same community, the nanophanerophytes, chamaephytes, hemicryptophytes and the interlayer plants accounts for a higher proportation in Zhifanggou, compared with Xiannangou, while hemicryptophytes the annual herbage plants account for a smaller proportion.(6) To the same community, the species richness, diversity and evenness of the Zhifanggou are generally higher than that of Xiannangou.10.The typical plant community floraComparison study on the flora of Quercus liaotungensis community was done between the LPNS with Qinling Mts. The result shows that there are 51 species of vascular plants belonging to 42 genera of 27 families in the LPNS, and 67 species of vascular plants belonging to 60 genera in 31 families in Qinling Mts.. the richness of plants species of Quercus liaotungensis community in the LPNS is poor and community structure simple. In addition, the similarity coefficient of Quercus liaotungensis community in the two areas is low. Studies on the floristic elements of plant genera and species were carried out to find that the Quercus liaotungensis community in both areas belongs to the temperate, and the endemic species to China in Quercus liaotungensis community of both areas are more in common with North China, less with Southwest China, Center China, East China and Northeast China.11.The rare and endangered plants.(1) The rare and endangered plants are comparatively rich in the LPNS. There are 75 species of protected plants, belonging to 63 genera of 44 families, among of which 35 species are the state protected plants, and 7 province protected plants and 33 regional protected.. According to endangered ranking system, these plants fit into 3 ranks, namely EN, VU and NT, and accordingly three protection levels. Therefore, these plants consist of 15 species of EN, 20 species of VU and 40 species of NT, 39 species of level one protection, 17 species of level 2 protection and 19 species of level 3 protection.(2) The areal types of the protected plants are mainly the elements of North Temperate, Old World Temperate, East Asia and Endemic to China, with the North Temperate elements dominating. The floristic elements of the protected plants are mainly Endemic to China, Temperate Asia and East Asia while the Endemic Species to China in the LPNS plays a dominant role, which are mainly composed of elements of North China, Endemic Species to LPNS and Southwest China-Center China-North China.12.The resource plants are rich. There are about 950 species which can be classified into 14 types by their use.更多还原