Studies On The Diversities And Edge Effect Of Orthopteran In Ecologically Restored Area Of Wuqi, Shaanxi

Abstract Wuqi County lied in the northwest of Yan'an city(N36°33′33″～37°24′27″, E 107°38′57″～108°32′49″, Altitude 1233～1809m).The annual mean temperature is 7.8℃. The annual average rainfall is 483.4mm, It belongs to semi-arid warm temperate territoriality monsoon climate. The paper mainly studied the composition, distributed structure, biodiversity, seasonal change and the edge effect of orthopteran communities in ecologically restored area of Shaanxi Wuqi by means of diversity index, principal component analysis and stepwise regression. The results are as follow:There were 10 families, 17 genera, 20 species of orthopteran in Wuqi, which included 1 genera, 1 species of Pamphagidae, 1 genera, 1 species of Pyrgomorphidae, 1 genera, 1 species of Cantantopidae, 6 genera, 7 species of Oedipodidae, and 2 genera, 4 species of Arcypteridae, 2 genera, 2 species of Acididae, 1 genera, 1 species of Tetrigidae, 1 genera, 1 species of Phaneropteridae, 1 genera, 1 species of Tettigoniidae, 1 genera, 1 species of Gryllidae. Among these species, Oedaleus infernalis comprised 17.58%, Pararcyptera microptera meridionalis 15.15%, and CaIliptamus abbreviatus 14.89%, of the total, being considered as dominant groups.The species-abundance model of different month site and ecotype all match basically to Preston's Lognormal distribution. The variational trend of diversity index is county center＞south＞northeast＞northwest. The results of PCA analyzing the vegetation factors and orthopteran communities are ideal, the cumulative percent of two principal components reach respectively 95.299% and86.304%. By stepwise regression analysis, it shows that there are several vegetation factors, which are grasses height diversity, grasses species number, gompositae dominance degree, gramineae dominance degree and other grasses dominance degree affect the species and numbers of orthopteran.The edge effect of orthopteran communities were studied among three types of edge zones in this region. On the whole, the orthopteran communities'diversity in edge zone are higher than those in the interior of adjacent communities at the similar edges. Two formulas measuring the intensitY of edge effect from the quantity of population and structure of community were used in analysis. They respectively are: EH'=mH'/ΣH_i; Ec=mC/ΣC_i. Through calculations, the characteristics of all kinds of edges can be decided by comprising the values of EH' with threshold value 1. If the value of EH' is bigger than1, then the edge effect is positive. Results show that EH' about all the edge are bigger than 1, it show the edge effect is positive.