Study On Flora Of Seed Plants In Qinghai Lake Basin,China

Qinghai Lake basin is located in the northeast of Qinghai-Tibet Plateau and Qinghai Province,Its geographical location is 36 ° 15 ′～38 ° 20 ′ N,97 ° 50 ′～101 ° 20 ′ E.It belongs to a fragile ecological environment area.Qinghai Lake plays an important role in maintaining the ecological security in the northeast of Qinghai Tibet Plateau and preventing the eastward expansion of desertification in the West,at the same time,this area has a special geographical location and ecological environment conditions,and is rich in biodiversity.Taking the seed plants in Qinghai Lake Basin as the research object,this paper established a list of wild seed plants in Qinghai Lake Basin through field investigation and collation of relevant literature.On this basis,the flora of seed plants in this basin was systematically studied by using the method of floristic geography.At the same time,statistical analysis method was used to compare the flora of this area with the dominant families,endemic genera and species and r/t values of other 8 adjacent areas in Qinghai Province.The similarity coefficient was used to analyze the similarity between Qinghai Lake Basin and the surrounding 5 areas,and to clarify the floristic characteristics of seed plants in Qinghai Lake Basin and its relationship with other areas.In order to provide data support for further protection of biodiversity and ecological environment in Qinghai Lake Basin.The main results were as follows:1.The species composition was abundant.There were 754 species of seed plants belonging to 265 genera and 70 families in Qinghai Lake Basin.In terms of the quantitative composition of families,Large families(≥ 100 species)included Asteraceae and Poaceae,The larger families(30～99 species)have 6 families.The larger families and the larger families are important constituent families in the basin;The single species family only includes ice marsh grass family scheuchzeriaceae 1 family,and 8 families of monotypic family.In terms of the quantitative composition of genera,small genera(2 ～ 4 species)and genera with 1species occupied the main position in the composition of river basin genera,with a total of230 genera;There were 15 monotypic genera and 21 genera of few specie.2.The dominant phenomenon was obvious and the characterization groups were abundant.The flora of Qinghai Lake Basin had 9 dominant families,including 133 genera and465 species.These families were distributed all over the world;The characterization families include five families: Salicaceae,Polygonaceae,Chenopodiaceae,Ranunculaceae and Gentianaceae;There were 21 dominant genera,mainly cosmopolitan and temperate;there were 9 characteristic genera,such as Lomatogonium and Ephedra;There were more than 60 dominant species and 12 characteristic species.3.The geographical composition of this flora was complex,showing the nature of temperate zone.There were seven distribution types of families in the flora of seed plants in Qinghai Lake Basin,and there were also seven varieties under them.Generally,they show temperate nature under the background of world distribution families.here were 13 areal types of genera,15 of which are more hypomorphic.The temperate distribution was dominant,207 genera,accounting for 93.24% of the total genera,of which the north temperate distribution was the most,followed by the Eurasian temperate distribution,and there were some other components;There were 11 distribution types of species,and only two variants were divided into East Asia.Like families and genera,the temperate distribution was dominant,with 723 species,accounting for 99.45% of the total species,of which China was the most endemic and closely related to the Himalayas.4.Endemic genera were poor and endemic species were abundant.There were no endemic families in the seed plant flora of Qinghai Lake Basin,and there were only 7 genera endemic to China,including Kengyilia,Notopterygium,Pomatosace,Przewalskia,Xanthopappus,Sinochasea and Porolabium,all of which were young endemic genera.There were 266 endemic species,in this area.The analysis of their distribution subtypes shows that this area was closely related to Hengduan Mountain area,southwest,northwest and North China.5.Through the comparison of dominant families,endemic species and R/T values,it was found that the seed flora in the Qinghai Lake Basin was less different from the Huangshui Basin,Datong River Basin and Longwu River Basin,and was more different from the upper Yellow River valley in eastern Qinghai,the Qaidam Basin,Sanjiangyuan National Park,and Animaqing Mountains.It belonged to the transition zone from the eastern flora to the northwest and the hinterland of the Qinghai-Tibet Plateau.By calculating the similarity coefficient,it was found that the Qinghai Lake Basin,Qilian Mountain National Park(Qinghai Area)and Yushu City had the closest relationship and close relationship,and the Anxi Reserve was the farthest and weaker in relationship,it was found that the Qinghai Lake Basin had a certain relationship with the Lhasa River Basin,which both belonged to the Qinghai-Tibet Plateau.6.There were 48 species of protected plants in Qinghai Lake Basin,belonging to 28 families and 37 genera,including 12 species of national key protected wild plants,21 species of provincial key protected wild plants in Qinghai,24 species of threatened plants and 4species of endangered plants listed in international trade convention cites.Based on the analysis of its protection status,the protection countermeasures were put forward.7.The Seed Flora of Qinghai Lake Basin belonged to the young flora formed during the uplift of Qinghai Tibet Plateau,and contained some ancient elements.