研究了六盘山区辽东栎(Quercus liaotungensis)灌丛的种子产量、土壤种子库组成、湿沙和风干贮藏对种子寿命的影响以及动物取食子叶对种子萌发和幼苗建立的影响。结果表明, 辽东栎灌丛种子的完好率为27.51%, 被动物取食或搬运种子的比例(41.51%)显著高于其他类型种子(p < 0.01); 辽东栎次生林土壤种子库中萌发和虫蛀种子分别占35.16%和38.29%, 完好种子仅占13.65%, 捕食动物主要通过贮藏或搬运而影响土壤种子库中的种子密度。湿沙贮藏60天的辽东栎种子自动萌发率高达96.67%, 短期贮藏可加快种子的萌发进程, 提高萌发率和萌发指数, 但随着贮藏时间的延长, 种子萌发进程延迟, 萌发率、萌发指数和活力指数均不同程度地降低。排除动物取食处理的幼苗在林窗和林下生境的存活率分别为80%和83%, 而不排除动物取食幼苗在2种生境中分别仅有25%和31%能够存活, 表明子叶在幼苗建立中具有重要作用。林窗中幼苗子叶的动物取食率(85.00%)高于林下(71.00%), 子叶留存的幼苗在林窗中的存活率(6.00%)低于林下(15.50%), 而子叶被取食幼苗的存活率在两种环境中基本相等(分别为18.50%和18.00%)。

Aims Quercus liaotungensis forest, which occurs on shaded, semi-shaded and semi-sunny slopes at an elevation of 1 700-2 300 m, is the main natural secondary forest and zonal climax community in China’s Liupan Mountains. It is essential for forest management to better understand the natural regeneration processes and limiting factors in the restoration of degraded Q. liaotungensis shrubs and secondary Q. liaotungensis forest. Our objectives are to (a) investigate the important ecological processes associated with recruitment and seedling regeneration (seed production, seed bank composition, seed storage and seed/cotyledon predation) and (b) analyze potential bottlenecks limiting seedling regeneration.
Methods We surveyed the seed production of Q. liaotungensis shrubs and soil seed bank composition of secondary Q. liaotungensis forest in Daliang Mountain and Qiuqianjia forest region of Liupan Mountains, respectively. We also investigated the effects of moist sand and natural air-dry storage on seed life-span and the effects of cotyledon predation (by excluding animals) on seedling establishment.
Important findings The percentage of viable seeds of Q. liaotungensis shrubs was 27.51%, and the rate of seed predation/removal (41.51%) was significantly higher than that of other seed types (P < 0.01). The rate of germination and insect infection in soil seed bank of secondary Q. liaotungensis forest was 35.16% and 38.29%, respectively, while only 13.65% of seeds were viable in the soil seed bank. Seed predators played an important role in influencing the density of the soil seed bank by removing and hoarding seeds. Storage in moist sand for 60 d resulted in germination of 96.67% of Q. liaotungensis seeds, and both short-term moist sand and air-dry storage led to accelerated germination timing and enhanced germination percentage and germination index. However, with the extension of the storage period, germination was delayed and germination percentage, germination index and vigor index were decreased. Survival rates of seedlings treated by predator elimination caged seedlings were 80% and 83% in forest gap and under canopy, respectively, while only 25% and 31% of survival rate, respectively, were found for uncaged seedlings, indicating the important role of cotyledons in seedling establishment. The predation rate of cotyledons in forest gaps (85.00%) was higher than that under canopy (71.00%). Although the survival rate of seedlings with cotyledons in forest gaps (6.00%) was higher than that under canopy (15.50%), the survival rate of cotyledon-predated seedlings in forest gaps (18.50%) was similar to that under canopy (18.00%).