关键词: 大青沟自然保护区, 森林群落, 优势种, 叶性状, 地形因子

Abstract: [Objective] This article investigated the influence of topographic factors on leaf traits of different forest plant communities in Daqinggou Nature Reserve in order to reveal the main driving topographic factors that influence the leaf functional traits.[Method] Ulmus macrocarpa, Quercus mongolica, and Fraxinus mandshurica in Daqinggou Nature Reserve were selected as research objects. Each community type was set five fixed sample plots of 20 m×20 m. In the plots the leaves of the species whose important values were greater than 0.1 were collected. The leaf thickness, the specific leaf area, the leaf dry matter content, the leaf size and the leaf dry mass of the dominant species in different community types were measured. The Pearson correlation analysis and stepwise regression analysis were used to study the relationship between the different leaf traits of dominant species in the different community types and topographical factors.[Result] The Pearson correlation analysis showed that there was a significant negative correlation between the specific leaf area and altitude, and a significant positive correlation between the specific leaf area and the slope position. There was significant positive correlation between leaf dry matter content and altitude, and a significant negative correlation between leaf dry matter content and the slope position, regardless of all the dominant species or the different growth forms. The stepwise regression analysis further indicated that altitude was the primary factor influencing all the leaf traits except leaf size of all the dominant species, leaf thickness and leaf dry mass of shrub species, and leaf thickness of herb species, which were influenced by slope position and the standard partial regression coefficient was 0.259, -0.508, -0.467 and 0.410, respectively. The standard partial regression coefficient was 0.285, -0.438, 0.504 and 0.146 respectively for the leaf thickness, the specific leaf area, the leaf dry matter content and the leaf dry mass of all the dominant species; standard partial regression coefficient was 0.494, -0.378, 0.563, 0.836 and 0.575 respectively for the leaf thickness, the specific leaf area, the leaf dry matter content, leaf size and leaf dry mass of tree species; standard partial regression coefficient was -0.336, 0.490 and 0.171 respectively for the specific leaf area, the leaf dry matter content and the leaf size of shrub species; standard partial regression coefficient was -0.555, 0.650, -0.357 and -0.271 respectively for the specific leaf area, the leaf dry matter content, the leaf size and the leaf dry mass of herb species.[Conclusion] Although the altitude difference is only sixty to seventy meters in Daqinggou nature reserve, the soil moisture obviously reduced with the increasing altitude. The change of soil moisture influenced the community composition. The difference in the community composition caused the changes in leaf functional traits. Thus altitude is the main driving factor that influences the leaf traits.

Key words: Daqinggou Nature Reserves, forest community, dominant species, leaf traits, topographic factors