Study On The Community Diversity And Regeneration Characteristic Of Typical Secondary Shrub Community In Midpiece Of Qinling Mountains

Shrub communities of vegetation in Qinling Mountain were typical and respresentative.Because of the developed roots and strong reproduce,they are the better species of soil andwater conservation,at the same time,improving the environment.The study chose four tipicalshrub communities were Fargesia qinlingensis community, Rhododendron clementinaecommunity,Rhododendron capitatum community and Coriaria nepalensiscommunity.Analysed the importance value,the similarity coefficient, species diversity, woodyplants regeneration and dominant species niche width part from shrub layer and herb layer.theresults are as follows:The total species of were79,including23species in shrub layer and56species in herblayer.The constructive species was Fargesia qinlingensis,the importance value was57.95%.Carex lanceolata was the dominant species in herb layer,the importance value was15.05%.Rubus corchorifolius,Spiraea salicifolia,Euony-mus alatus,Quercus aliena,Cornuscontroversa,Cotoneaster horizontalis were the sub-dominant species.Rosaceae is morecommon in this kind of community. Rhododendron clementinae shrub communities were14species in shrub layer and26species in herb layer.The importance value of was30.95anddominant species in herb layer was13.17that followed by Oxalis corniculata.Other herbspecies importance value were less than10%.In Rhododendron capitatum community, theshrub layer were a total of seven kinds,of which the first flower Rhododendron capitatumimportant value of49.27%,the Fargesia qinlingensis,Potentilla glabra value, the threepopulations in The community has an absolute advantage and a total of39species;Rhododendron capitatum community herb layer species, a large number of Carexlanceolata Boott, and the Melica scabrosa values were13.73%,12.21%, followed by forPhlomis umbrosa,Saussurea purpurascens page,Carex agglomerata, other species importantvalues are less than4.00%. Shrub layer the Coriaria nepalensis community a total of29species, the species is more abundant, Coriaria nepalensis important value of25.95%, fouraccording to Cornus kousa subsp. Chinensis8.36%, Lespedeza bicolo5.74%, less important value of other species; Coriaria nepalensis community herb layer species of52, Artemisiaroxburghiana value, was5.43%, the herbs layer of the community, the important value of thespecies or less.Shrub communities in shrub layer and herb layer similarity coefficient is different,Fargesia qinlingensis and Coriaria nepalensis communities similarity coefficient were larger,and species similar in both communities. Research four shrub communities in the herb layerpopulation similarity coefficient greater than the shrub layer, the Fargesia qinlingensis andCoriaria nepalensis communities similarity coefficient was0.404, Coriaria nepalensis andRhododendron clementinae communities minimum similarity coefficient was0.152, the orderof herb layer similarity coefficient was:Fargesia qinlingensis and Coriaria nepalensiscommunities> Coriaria nepalensis and Rhododendron capitatum communities> Fargesiaqinlingensis and Rhododendron capitatum communities> Rhododendron clementinae andRhododendron capitatum communities> Fargesia qinlingensis and Rhododendron capitatumcommunities> Coriaria nepalensis and Rhododendron clementinae communities. In fourtypical shrub community in shrub layer, Rhododendron clementinae and Rhododendroncapitatum community similarity coefficient,0.286, niitakayamensis gold back cuckoocommunity similarity coefficient minimum of0.108. In the four shrub community in theshrub layer, the order of the similarity coefficient: Rhododendron clementinae andRhododendron capitatum communities> Fargesia qinlingensis and Coriaria nepalensiscommunities> Coriaria nepalensis and Rhododendron clementinae communities> Fargesiaqinlingensis and Rhododendron capitatum communities>Coriaria nepalensis andRhododendron capitatum communities>Fargesia qinlingensis and Rhododendron clementinaecommunities.The diversity of four different shrub cmmunities were large,the shrub layer was less thanherb layer. Coriaria nepalensis community was the largest overall and then Fargesiaqinlingensis community.Because its strong reproduce,Fargesia qinlingensis was limited othershrubs to grow up in shrub layer that led to the diversity of Rhododendron clementinaecommunity was more than Fargesia qinlingensis community.In shrub layer of Fargesia qinlingensis community,the maximum niche breadth was0.95.The8domonant species in herb layer were large and had small diffrence among them.Saussurea japonica was the largest which was0.86. Rhododendron clementinae was thelargest in shrub layer of Rhododendron clementinae community which was0.85,following byRubus corchorifolius, Abies fargesii, Rosa multiflora. Rhododendron capitatum andRhododendron purdomii were the minimum. Fragaria vesca was the largest in herb layerwhich niche breath was0.65,following by Pyrola calliantha, Oxalis corniculata, Carexrigescens, Anthriscus sylvestris, Pimpinella anisum.In the Rhododendron capitatumcommunity, Rhododendron capitatum was0.90.following by Potentilla glabra, Spiraeaalpine, Salix takasagoalpina, Fargesia qinlingensis, Lonicera hispida, Cotinus coggygria;Saussurea purpurascens was the largest which has0.70in herb layer, Carex lanceolata andPhlomis umbrosa were0.68.These3species had small difference.They adapted the same environment conditions and had better utilization of environment resources,following byCardamine macrophylla, Primula malacoides, Carex agglomerate, Melica scabrosa. Coriarianepalensis niche breadth was0.91.The distribution was equality,following by Lonicerafragrantissima, Lespedeza bicolor, Cornus kousa subsp. Chinensis, Campylotropismacrocarpa.In addition to Coriaria nepalensis, several other dominant species niche breadthhad small difference that range with about0.4-0.6. Plantago asiatica was the largest in herblay which niche breath was0.89,following by Aster tataricus, Artemisia roxburghiana,Arthraxon hispidus, Fragaria vesca, Elymus dahuricus.Because of its wider distributionhigher utilization of environmental resources,its had larger niche.The major regenerate mode was shrub sprout in four different shrub cmmunities and theother mode were less.The percentage of shrub sproutings was Fargesia qinlingensis>Rhododendron capitatum>Rhododendron clementinae>Coriaria nepalensis. Fargesiaqinlingensis has the largest percentage and the density also the largest,following byRhododendron capitatum, Coriaria nepalensis, Rhododendron clementinae.The diversity and regeneration of Coriaria nepalensis and Fargesia qinlingensiscommunities were better than Rhododendron clementinae and Rhododendron capitatumcommunities.According to the regular pattern of shrubwood,enclosure and rationally artificialmeasures could be effective ways to the positive succession of the shrub community andincrease diversity.There would be important to recover and rebuild in degrading ecosystem.