Ten years' observation of seed rain in a Fagus lucida community in Dalaoling Nature Reserve in the Three Gorges: seed rain density, species composition and their correlation with the community
湖北三峡大老岭自然保护区光叶水青冈群落种子雨10年观测: 种子雨密度、物种构成及其与群落的关系

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.