毛红椿天然林种子雨、种子库与天然更新

Seed rain,soil seed bank,and natural regeneration of natural Toona ciliata var.pubescens forest

2008—2011年,调查江西九连山国家级自然保护区毛红椿天然林的种子雨、种子库及林下幼苗数量.结果表明:在毛红椿天然林,种子雨散布时间为10月下旬至12月下旬.2010年不同样地的种子雨强度为虾公塘气象观测站(320.3±23.5粒·m-2)>虾公塘保护站(284.7±24.2粒·m-2)>大丘田保护站(251.6±24.7粒·m-2),分别以222.0、34.3和22.6粒·m-2完好种子供土壤萌发更新;毛红椿种子储量取决于结实量、鸟类取食和种子活力等因素,鸟类取食是其种子储量大幅下降的首要因素;由于种子不耐储藏以及大量腐烂,种子有效贮藏期不足1个月.12月天然林种子库平均萌发数≤2株·m-2,次年1月土壤种子库种子量最少,为6.7～11.8粒·m-2,平均仅萌发0.4～0.6株·m-2,与林下实生幼苗分布极少相吻合.毛红椿种子雨储备、种子库种子活力保存及幼苗建成等因素影响其天然更新.

Taking the natural Toona ciliata var.pubescens forest in the Jiujiangshan National Nature Reserve in Jiangxi Province of China as test object,an investigation was conducted on the seed rain,soil seed bank,and seedlings number in 2008-2011.The seed rain of the forest was dispersed from late October to the end of December.In 2010,the seed rain intensity in different sampling plots was in the order of Xiagongtang observatory（320.3±23.5 seeds·m-2） Xiagongtang protection station（284.7±24.2 seeds·m-2） Daqiutian protection station（251.6±24.7 seeds·m-2）,and the quantity of the intact seeds in soil supplied for seed germination and regeneration was 222.0,34.3,and 22.6 seeds·m-2,respectively.The seed bank reserves was affected by the seed production amount,bird feeding,and seed viability,etc.,of which,bird feeding was the prime factor for the substantial drop of the seed bank reserves.Due to the low resistance against storage and a large number of rot during storage,the seeds in soil could hardly be effectively stored beyond one month.The seedlings germinated in December were averagely less than 2 stands·m-2,and the soil seed reserves in the next January was the least（6.7-11.8 seeds ·m-2）,with the germinated seedlings averagely 0.4-0.6 stands·m-2,which was consistent with the rare distribution of natural seedlings in the forest.It was concluded that the small seed rain reserves,low seed vigor of soil seed bank,and low seedling establishment were the important factors impacting the natural regeneration of T.ciliata var.pubescens.