啮齿动物和鸟类对东灵山地区辽东栎种子丢失的影响

20 0 0年 8月中旬至 10月上旬 ,在北京东灵山地区小龙门林场选取两块辽东栎分布近似而坡向不同的样地 ,并对样地内种子库与啮齿动物的种群数量变化进行了调查。结果表明 ,两块样地种子雨持续 4 0天左右 ,且种子下落趋势基本一致 ,高峰期都集中在 9月中旬 ,不同坡向的种子产量差异显著。在两样地随机各设置 2 4个种子方形收集器 (0 5m2 )和 2 0个地表样方 (1 0× 0 5m2 )调查种子产量。通过比较收集器内壳斗和种子数量 ,发现二者无显著差异 ,说明鸟类对林冠层种子丢失作用不明显 ;而收集器和地表样方种子数量差异显著 ,表明辽东栎种子库扩散主要由林中啮齿动物完成。标记重捕发现辽东栎林中啮齿动物群落包括大林姬鼠 ,社鼠 ,棕背鼠平和花鼠 ,其中大林姬鼠为优势种 ,占群落的 77.2 %。

Influence on seed bank of Quercus liaotungensis by birds and rodents in Dongling Mountain

Two plots with different slopes were selected for seed rain test in Liaotong oak (Quercus liaotungensis) forest in Dongling Mountain region of Beijing. The characteristics of seed bank and the population of rodents in the two plots were conducted from mid-Aogust. to the beginning of October. 2000. Results showed that the seed rain of Liaodong oaks continued about 40 days. The characteristics of the seed rain in two plots paralleled well and most seeds fell in mid-September, but the seed productivity were different in the two plots. Twenty-four traps above ground and twenty small plots on ground (about 0 5 m 2) were randomly located in each plot. Significant difference in the seed crop size was found between traps in the air and on the ground in the two plots, yet no significant difference was found in the number of cups and acorns inside the traps. Our results indicated that birds showed little impact on the seed bank of oak in this area, but rodents showed a heavy impact on the seed bank. Four species of rodents, Apodemus peninsulae, Niviventer confucianus,Clethrionomys rufocanus and Eutamias sibiricus might contribute to the ground seed dispersal. The dominant species Apodemus peninsulae which accounts for 77 2% of the community might have the most important impact on seed dispersal.