Abstract: The plant species observation and experimental station was an important component of the biological and environmental monitoring system for the Three Gorges Project. 5 onehectare permanent plots were established from 1996~2002, including broad leaved evergreen forest, mixed broad leaved deciduous and evergreen forest, deciduous forest and evergreen conifer forest. All the permanent investigation plots provide the basis for the longterm biodiversity dynamic research. In this paper, some achievements in the research stations were introduced. The distribution of a mixed broad leaved deciduous and evergreen forest patterns were detected. Two dominated species, Fagus engleriana and Cyclobalanopsis oxyodon, were all clumped. The oxyodon population was divided into three size classes as DBH 1 ~4 cm, DBH 4 ~8 cm and DBH > 8 cm, all of which were clumped, and might be influenced by the age of the forest and the topographic factors. Microsite heterogeneity was one of the important mechanisms in maintaining species diversity in plant community. To examin the heterogeneity of the topography, a DEM was built using the interpolation method. The slope and aspect driven form DEM showed strong heterogeneity. The slope varied from 18.2° to 74.6°, and from south, to southwest and southeast. Twentyfour species were chosen to calculate correlation coefficients between slope, aspect and position. The topographic adaptation of these species was different, for example Fagus engleriana was positively associated with slope, and Sorbus alnifolia was positively associated with other aspects and so on. According to topography, these species were classified into six groups using a hierarchical cluster analysis. All the achievements in the research station will contribut to the biodiversity reservation in the future.

Key words: Shennongjia Region, biodiversity, permanent plot