Spatiotemporal dynamics of seed rain in a broadleaved-Korean pine mixed forest in Xiaoxing′an Mountains, China
小兴安岭阔叶红松(Pinus koraiensis)林种子雨的时空动态

Spatiotemporal dynamics of seed rain is important for understanding community regeneration mechanisms and vegetation patches distribution patterns. We established 287-319 seed traps in a 150m×150m sample plot of the 9-ha permanent plot to collect and identify fallen seeds from 2005 to 2007 in a broadleaved-Korean pine(Pinus koraiensis) mixed forest at Liangshui Natural Reserves. The results showed that: (1) The intensity of seed rain for tree species had a great interannual variation, (864.2±1084.3), (300.9±349.4), (144.8±195.5) inds m-2, in 2005, 2006 and 2007, respectively. The intensity of seed rain of the 11 tree species included also showed a great interannual variation, and the density of Fraxinus mandshurica, Tilia mandshurica, Betula platyphylla, Picea koraiensis and Abies nephrolepis in certain years was little. However, the intensity of Pinus koraiensis was influenced by human disturbance. (2) Seasonal dynamics of the seed rain were significant. The seed rain started in May, reached a peak in October, and ended in the middle of November. But the temporal pattern of each tree species was different. From the peak of the seed rain phase, the seed rain was mainly made up by intact seeds, but at the beginning the seed rain was mainly by vacant seeds. (3) The seed rain components were stable among years. (4) The spatial heterogeneity of the seed rain varied among years, and it was positively correlated to the intensity of seed rain.