Plant Diversity Of Subalpine Sphagnum Mires In Western Hubei Province

Sphagnum mire occupy extensive tracts of land throughout the Boreal and Subarctic regions.In China,sphagnum mire mostly develop in Daxinganling,Xiaoxinganling and Changbaishan,et al.But,the large areas sphagnum mire in subtropical zone was rare. From 2005 to 2006,3 subalpine sphagnum mires were discovered successively at Qizimei Mountains,Erxianyan and Haichi in subtropical regions in Western Hubei province.During the period of 2005～2006,preparatory field investigation of plant diversity were carried out on these sphagnum mires in Western Hubei province.The main results are given as follows:1.The results show that the species composition of the 3 sphagnum mires was relatively rich,201 species(including variety)of plants,belonging to 130 genera of 64 families,were recorded.Among these,94 species,41 families belong to sphagnum mire at Qizimei Mountains;111 species,51 families belonging to mire at Erxianyan;and 94 species,42 families belonging to mire at Hanchi.There are 32 families,50 genera and 65 species belonging to wetland species among the 201 plant species.And the number of the species is 32.34%of the total species number.The results show that the xerophil and mesophyte are rich in the sphagnum mire in Western Huibei province.2.The association types of sphagnum mires in westren Huibei province are rather abundant.Altogether,25 vegetation associations is differentiated in the 3 sphagnum mires.Among these,there are 18 sphagnum-dominated associations.There are 9 sphagnum-dominated associations in Qizimei Mountains,there are 7 sphagnum-dominated associations in Erxianyan,and there are 6 sphagnum-dominated associations in Hanchi.3.In the sphagnum mires in western Huibei province,the water content of sphagnum is about 94.71%.The biomass of sphagnum is dominant in the herbage biomass of sphagnum-dominated associations.The biomass magnitude of the association lies on the biomass magnitude of sphagnum.4.The total coverage of each association in the 3 sphagnum mires approach to 100%,and the average coverage of sphagnum is 89.66%.The importance value of the sphagnum in 75%of the quadrats is more than the importance value of other dominant species.To sum up,sphagnum get the ascendancy over the 3 sphagnum mires in western Huibei province.5.α-diversity with Patrick richness index(R),Simpson dominance index(C),Shannon-Wiener diversity index(H′)and Pielou evenness index(J)was measured.The 4 indices show the characteristics of the species diversity from different aspect of the 3 sphagnum mire communities in western Huibei province.By compare the 4 indices of herbage sphagnum-dominated associations of 3 sphagnum mires,we can conclude that the maximal richness index,diversity index,evenness index and the minimal dominance index of the sphagnum-dominated community occur in Qizimei Mountains;but the maximal dominance index and the minimal richness index,diversity index,evenness index of the sphagnum-dominated community occur in Erxianyan.In addition,there is not obvious linear relationship between the biomass and the species richness(R)of the herbage sphagnum-dominated community in 3 sphagnum mires.6.βdiversity or the species replacement rate become more and more small from the meadow to sphagnum mire in mire-meadow ecotone at Erxianyan,community gradually become stable.The result suggest that the disturbance from human on the plant community reduce gradually from periphery of sphagnum mire to sphagnum mire.7.The actuality of the plant diversity is that sphagnum is harvested severity; channel,drain and mining bring on degeneration of sphagnum mire;area of sphagnum mire have dwindled remarkably and vegetation fragmentation by agricultural activity;the xerophil intrude into sphagnum mire.