山杏的种子雨及鼠类的捕食作用

山杏(Prunus armeniaca)是一种灌木状小乔木，在北京山区较为贫瘠、干旱的阳坡地带广泛分布。于2002年7月和2003年7～9月，采用种子收集筐估计了山杏种子的产量、种子雨的动态变化过程；在2003年的研究中，把收集筐中所获得的种子转入扣网之中以排除鸟类的影响，并设置了地表对照样方，调查和比较了扣网内和对照样方中、扣网和对照样方之间山杏种子被取食、搬离的动态变化及其差异性。研究表明，山杏种子的下落高峰发生于7月下旬至8月上旬，败育种子的下落早于完好种子且数量极少；在扣网内和对照样方中，被取食和被搬运的种子数量之间存在显著性差异，在扣网和对照样方之间．被取食和被搬运的种子数量的差异均未达到显著性水平；鼠类是种子雨期间取食山杏种子的主要动物．鸟类的作用可以忽略。

Seedrain of wild apricot and predation by small rodents

Wild apricot (Prunus armeniaca),a shrub-like small arbor,is distributed widely on sunny slopes of mountainous areas of Beijing,that survives well under dry conditions with poor soil or in deforested hills.Few studies had been done on the production and seed-rain,much less on the effect of consumption and removal by small rodents on dynamics of seed-bank.During July,2002 and July to September,2003,we estimated the production and seed-rain of wild apricot using collecting basket.The sample size was 16 and 20,in 2002 and 2003,respectively.The differences between consumed seeds and removed seeds within exclosure and ground quadrat,and the differences between exclosure and ground quadrat were compared.The results showed that the seed production of wild apricot varied significantly among years,and the peak of seeds falling occurred from late July to early August,among which the aborted seeds fell prior to the intact ones.There was significant difference between consumed and removed seeds both within exclosure and ground quadrat,which suggested that rodents tended to eat and transport seeds from the same sites.The difference of consumed seeds and removed seeds,respectively,between exclosure and ground qnadrat were not significant,which indicated that rodents were the main factor affecting the fate of seeds in seed-bank of wild apricot in the course of seed-rain,and the impact from birds was negligible.The percentage of seeds consumed and removed by rodents was low compared to the productivity.