Flora Characteristics And Species Diversity Of Communities In Shigao Mountain

Shigao Mountain is located in the southeast of Lingshi county, Shanxi Province, the famous mountain lying in middle south of Shanxi Province. This paper studied flora characteristics and species diversity of main plant communities in this region. The results were as followes:(1) Shigao Mountain had rich plant resources, a total of 78 families,222 genera and 413 spermatophyte, including 4 families,7 genera and 10 species of gymnosperms,74 families,215 genera and 403 species of angiosperms. The species which these big families, such as Compositae, Papilionaceae and Rosaceae contained accounted for 26.15%, the species which genera contained 2-5 specie accounted for 51.33%, these families and genera played important roles in composition of spermatophyte in this region.(2) Areal-type of family was dominated by Widespread type, a total of 30 families; Tropical distribution type included 25 families, Temperate type included 22 families, Those wood families including Pinaceae, Betulaceae, Salicaceae, Fagaceae were constructive or dominant species of communities; as to areal-type of genera, Temperate type were predominant, a total of 145 genera, accounting for 65.32% of the total number of genera, which reflected temperate nature of the flora. Larix, Picea, Pinus, Populus, Betula, Quercus, Rosa, Sorbus, Spiraea, Elaeagnus, Lonicera, Viburnum, Caragana and Campylotropis were constructive or dominant parts for forests and shrubs.(3) Species richness of forest community (R) and Shannon-Wiener index (H) showed:in forest communities, herb layer> shrub layer> tree layer; in shrub of Ostryopsis davidiana mixed with Spiraea trilobata, and shrub of Hippophae rhamnoides mixed with Rosa xanthine, herb layer> shrub layer. In shrub of Vitex negundo var. heterophylla, Shannon-Wiener index (H) in shrub layer was higher than in herb layer. The tendency of evenness index was inconsistent in that of species richness index and diversity index:for forest of Pinus tabulaeformis, tree layer> shrub layer> herb layer; for forest of Quercus liaodungensis and forest of Pinus tabulaeformis mixed with Quercus liaodungensis, shrub layer> tree layer> herb layer; for most of the rest forest community:herb layer> shrub layer> tree layer; for shrub community:shrub layer> herb layer.(4) There were different of species richness index and diversity index and evenness index amonglO communities:for forest of Pinus tabulaeformis and Forest of Larix principis-ruprechtii, species diversity index and evenness index were higher; for forest of Quercus liaodungensis andForest of Betula platyphylla mixed with Quercus liaodungensis, richness indexes were higher, while diversity index and evenness index were lower; for forest of Pinus tabulaeformis mixed with Populus davidiana, forest of Pinus tabulaeformis mixed with Quercus liaodungensis, forest of Betula platyphylla mixed with Quercus liaodungensis, richness index, diversity index and evenness index were between deciduous broad-leaved and coniferous forest; for three kinds of shrub communities, species richness indexes were all lower.(5) With the increase of the elevation, Patrick index R and Simpson diversity index D showed changing trends of rise first and then decrease. However, Shannon-wiener diversity index (H), evenness index (E1 and E2) presented the opposite changing tendency, in other words, the three indexes presented trend of decrease first and then rise along with the increase of elevation.