Community characteristics of vegetation in earthquake disturbed zone in Longnan, Gansu

The seismic disturbance causes great damages to the local ecological environment, which leads to the changes of species composition and structure of vegetation community. The present paper investigated and analyzed the species composition and structure of vegetation community after earthquake disturbance in Qingshui Gully,Wudu District, Longnan City of Gansu Province from August to September of 2013 using the methods of belt transect combined with altitudinal gradient. The results showed that there were 34 plant species which belong to 30 genera,16 families in the study area although the main vegetations were Gramineae and Compositae plants. There was obvious vertical structure of vegetation community which could be divided into three layers. The perennial herbs were dominant which had the highest species number in the community. The shrub and vine followed and no arbor was observed. The Shannon-Wiener index (H') and Pielou evenness index (E) decreased in the following order: middle slope>lower slope>upper slope, and Simpson dominance index (D) decreased in the following order: upper slope>lower slope>middle slope.