The Structural Characteristics And Species Diversity Of Plant Communities In The North Slope Of Taibai Mountain

As geography and climate of the dividing line for south China and north China, Qinling Mountain has the special biodiversity and the plant community characteristic. As the Qinling highest mountain, the Taibai Mountains have the special geography condition, the complex environment gradient, the highly different electron particle materialization habitat and the relatively few human disturbances. Therefore the research of structural characteristics and species diversity of plant communities is advantageous to the distribution characteristics of vegetable and plant protection.This research investigate plant resources and the typical community of Taibai mountain from June 2009 to October 2010, on this basis, and carries on the reorganization and the statistical analysis to the entire region's data. The structural characteristics and species diversity of plant communities in the north slope of Taibai Mountain by Importance value, Species richness index, Species diversity index, Evenness index, community type, floristic components, height class and DBH class structure.The structural characteristics and species diversity of plant communities are described in Taibai mountain. The results as follows:(1)There are 413 plants in the north slope of Taibai Mountain, belonging to 63 families and 202 genuses. The Rosaceae family is most (49 species). The Compositae family is secondly (39 species). The least is Oxalidaceae and so on (1 species).Families containing genus 2~ 5 genuses is most (33 families), accounts for 52.38%. Families containing genus 6~ 9 genuses is least (1 families), accounts for 1.59%. Families containing species 2~5 species is most (32 families), accounts for 50.79%. Families containing species 10 species is least (8 families), accounts for 12.70%. Genus containing species 1 species is most (129 genus), accounts for 63.86%. Genus containing species 10 species is least (2 genus), accounts for 0.99%.(2) The geographic distribution of seed plant is complex in the north slope of Taibai Mountains. In all dispersion patterns, the North Temperate is most (74 genus), such as Lonicera, Saussurea and so on. Trop. Asia & Trop. Amer. Disjuncted, Old World Tropics is least.(3) The statistic of growth form community of the north slope of Taibai Mountains as follow: Herb is the most, accounts for 57.87%, shrub is secondly, accounts for 27.85%, and vine is the least, accounts for 2.66%. Life-form spectrum of vegetation as follow: The most life-form spectrum of vegetation is annual plant, and it's accounts for 43.34%. The secondly is phanerophyte, accounts for 33.90%.The least is geophytes.(4) The species abundance index increase first, and then decrease as the altitude increase. The biggest abundance index is at an elevation of 2200m. There were a similar profile of Shannon index, Simpson index and Evenness index as the altitude increase. They increase first, and then decrease, and the most is at an elevation of 2600m-2700m.(5) The community's vertical stratification is as follow: The community of Quercus aliena and Quercus liaotungensis are divided into 5 levels. The community of Betula albo-sinensis and Betula albosinensis are divided into 4 levels. The community of Larix chinensis and Abies fargesii are divided into 3 levels.(6)The DBH class structure of Quercus aliena and Quercus liaotungensis are Unimodal type and it is community downturn. The DBH class structure of Betula albo-sinensis, Betula albosinensis and Larix chinensis are Sporadie type,and the first two community is community downturn,but Larix chinensis is population growth form. The DBH class structure of Abies fargesii is L type, and it is population growth form.