【摘要】 种子雨是植物种子扩散的起点,对群落更新及种群动态起着关键作用。该文以三峡大老岭自然保护区内一片面积为1.3hm2的光叶水青冈(Fagus lucida)群落固定样地为研究对象,运用分层随机设计,在10个不同的地形部位放置了100个种子雨收集框,自2001年起进行种子雨观测,对该群落种子雨的数量与物种多样性的年际动态、种子雨和群落物种构成的关系等进行了统计分析。结果表明:1)过去10年间,共收集到来自48种木本植物的60926粒种子,种子雨的多年平均密度为(82.9±61.5)seeds·m–2·a–1(mean±SD),平均物种丰富度为(16.7±5.5)species·a–1(mean±SD)。2)种子生产的种间差异极为显著,种子量排名前三的植物贡献了累计种子雨总量的70%。3)群落种子雨的密度和物种丰富度在10年中基本同步,均呈现显著的周期性波动,并出现了3个大年。乔木和灌木种子雨密度的年际波动无显著相关性,但物种数变化显著正相关;4)种子雨与样地群落共有种为23种,分别占种子雨和群落中木本植物种数的47.92%和54.76%,但这些共有种贡献了种子总量的96.22%,表明扩散限制在研究群落中十分显著。与国内其他森林群落种子雨研究结果相比,该研究群落的种子雨密度明显较低。更多还原

【Abstract】 Aims Our objective was to analyze the temporal dynamics of the number and species composition of the seed rain of a Fagus lucida community and determine the relationship of species composition between seed rain and the community. Methods For ten years, we studied the seed rain in a 1.3 hm2 plot in the Dalaoling Nature Reserve of the Three Gorges Region, using 100 seed traps at ten different topographic positions. Important findings A total of 60 926 seeds from 48 woody species fell into the traps, the average seed rain density was (82.9 ± 61.5) seeds·m–2·a–1 (mean ± SD) and the average species number was 16.7 ± 5.5 (mean ± SD) per year. The interspecific difference of seed production was striking, with the top three species having contributed 70% of the total seeds. The interannual variation of seed rain density and species richness was synchronic, both revealed periodic fluctuations including three mast years. There was no correlation of seed rain density between trees and shrubs, but a significant positive correlation was found in species richness of these two life forms. There were 23 woody species shared by the seed rain and the community, accounting for 47.92% of the species richness in seeds and 54.76% in the community. However, the 23 species contributed 96.22% of the total seed rain, indicating that dispersal limitation occurred in this community. Compared with other forest community types in China, the seed rain density of this community is significantly lower.更多还原