Research On Vegetation Ecology In Areas Of Western Hubei Province

The area of West Hubei province is located on the junction of Hubei province,Henan province,Shanxi province and Chongqing municipality and lies in the central region of Qinling-Daba Mountains in the middle reaches of Hanjiang River.It has both the abundant habitats and high biodiversity,it is the area that forests are distributed comparatively intensively as well as the area that has the most nature reserves in Hubei province.Flora data were collected from seven nature reserves(nature reserves of Zhang he-yuan,Du he-yuan,Wu duo-feng,Ba gua-shan,Nanhe,Wu dao-xia,Ye ren-gu)in which vegetation was better preserved in West Hubei province and floristic composition there was analysized in this thesis.137 releves in total were accumulated on the basis of previous field investigations in these seven nature reserves.Vegetation types in western Hubei province were classified by the combined use of methods of Braun-Blanquet classification and quantitative classification(clustering analysis).Vegetation classification level was determined and vegetation classified system was accomplished.The main results are given as follows:? Flora characteristics in areas of western Hubei province(1)Plant species are richThere are 225 families,1173 genera and 3921 species of vascular plants in western Hubei province,among them,pteridophyte has 39 families,90 genera and 281 species,gymnosperm has 8 families,25 genera and 50 species,angiosperm has 178 families,1058 genera and 3590 species(137 releves contain 147 families,493 genera and 1054 species,including 21 families,38 genera and 72 species of pteridophyte and 126 families,455 genera and 982 species of spermatophyte).Vascular plants in western Hubei province account for 93.36 percent of total families,80.76 percent of total genera and 65.13 percent of total species in Hubei province,respectively;and 63.74 percent of total families,36.91 percent of total genera and 14.09 percent of total species in China,respectively.(2)The geographical components of plants are complex and diversePteridophyte in study areas contain all the 13 distribution types,the ecotypes are comparatively diverse;186 families of spermatophyte can be divided into 14 distribution types,only lack two types including Temperate Asia and Central Asian;1083 genera of spermatophyte contain all the 15 distribution types.Moreover,there are many subtypes included.This suggests that the geographical components of plants in study areas are complex and diverse.(3)Floristic element is dominated by temperate characteristic,but has the transitional characteristic simultaneouslyAmong all Pteridophyte in study areas,genera of tropical distribution account for 42.22 percent of the total,genera of temperate distribution account for 28.88 percent of the total,showing that flora of Pteridophyte in study areas is dominated by tropical characteristic.However,among all spermatophyte,there are 356 genera of tropical distribution and 544 genera of temperate distribution,accounting for 34.60 percent and 52.87 percent of the total,respectively,showing that flora of spermatophyte in study areas is dominated by temperate characteristic.On the whole,floristic element in western Hubei province is dominated by temperate characteristic,but has the transitional characteristic from subtropical nature to temperate nature.(4)Endemic compositions are comparatively diversiform and the flora is charac-terrized by antiquity,primitiveness and relict.Among the floral elements in western Hubei province,many ancient and primitive families and genera are distributed intensively:among the 186 families of spermatophyte,there are 25 single-species families,accounting for 13.44 percent of the total,and many of them are ancient and relict types.Among the 14 Asian endemic families in china,plants in western Hubei province have 10 families,accounting for 71.43 percent of the total.Among the 10 families,Ginkgoaceae,Eucommiaceae,Nyssaceae are Chinese endemic families.In terms of the genera level,there are 54 Chinese endemic genera,accounting for 5.25 percent of the total genera of spermatophyte.These suggest that the flora in study areas has the ancient,primitive and rudimentary character.? Classification of vegetation types in western Hubei provinceVegetation in western Hubei province can be classified into 7 alliances,28 associations and 5 typical communities.(?)Alli.Carex subpediformis1.Ass.Cotinus coggygria var.pubescens2.Ass.Ouercus serrata var.brevipetiolata(?)Alli.Acer oliverianum3.Ass.Fargesia robusta4.Ass.Euptelea pleiosperma(?)Alli.Dendrobenthamia japonica var.chinensis5.Ass.Ouercus aliena6.Ass.Cyclobalanopsis multinervis7.Ass.Pinus armandii8.Ass.Ouercus spinosa9.Ass.Eriophorum comofum10.Ass.Taxus chinensis11.Ass.Castanea seguinii(?)Alli.Pterocarya stenoptera12.Ass.Pterocarya stenoptera(?)Alli.Dipteronia sinensis-Chrysosplenium macrophyllum13.Ass.Dipteronia sinensis-Chrysosplenium macrophyllum(?)Alli.Juglans cathayensis-Coniogramme japonica14.Ass.Sycopsis sinensis15.Ass.Lindera megaphylla16.Ass.Iris japonica17.Ass.Cyclobalanopsis glauca18.Ass.Pterocarya hupehensis-Pilea notata19.Ass.Rubus coreanus20.Ass.Cyclobalanopsis myrsinaefolia21.Ass.Cinnamomum bodinieri22.Ass.Phyllostachys nidularia23.Ass.Ouercus acrodonta24.Ass.Pterocarya insignis25.Ass.Loropetalum chinense26.Ass.Ormosia hosiei27.Comm.Camellia oleifera28.Comm.Catalpa bungeii29.Comm.Zelkova schneideriana30.Comm.Emmenopterys henryi31.Comm.Corylus heterophylla32.Ass.Ginkgo biloba(?)Alli.Fagus engleriana-Fargesia spathacea33.Ass.Fagus engleriana-Fargesia spathaceaThis is the first vegetation research in West Hubei province that was conducted with combining the sample plot investigation,which has great significance in terms of vegetation protection and restoration as well as construction and management of nature reserves in West Hubei province.