关键词: 昆虫群落, 多样性, 稳定性, 主分量分析, 凉水自然保护区

Abstract: Magnolia officinalis subsp.bilobais an endangered plant in China. This paper studied the fruit and seed traits of different M. officinalis subsp.biloba populations, aimed to understand why this plant species is endangered. M. officinalis subsp.biloba fruited less, with the average number of fruits per plant being 3.19. There were significant differences in the fruit traits among different populations, and the variation mainly came from both among and within the individuals. The mean variance components of fruit characters were higher than those of seed characters, indicating that fruit was easily affected by the environment. The fruit characters had significant correlations with crown density and soil nutrient contents, and the seed characters including diameter, weight, and thickness had negative correlation with altitude but poor correlation with habitat and soil conditions. The low fruiting rate per plant and the low seed production rate per fruit could be the main factors causing the endangering of M. officinalis subsp. biloba.

Key words: insect community, diversity, stability, principal component analysis, Liangshui Natural Reserve.