Abstract:

Pinus koraiensis is mainly distributed in the northeast region of China. It is the Pinus genus of Pinaceae family of evergreen woody plants with large seed quality. When its cones mature, the seed scales cannot open naturally and cannot rely on water, wind, and other media to spread the seeds. They mainly rely on rodents and birds that feed on their seeds to spread the seeds through dispersed scatter hoarding. There have been many studies on the effects of seed size on rodent hoarding behavior and seed transportation, but the results of effects of seed size on seed transport and the fate of different plants remain controversial. Therefore, we investigated the transporting and hoarding preferences of rodents for seeds of different sizes in the Wangyedian Forest in Chifeng, Inner Mongolia. To further examine different sizes of seeds consumed and transported by rodents, we released large, medium, and small Pinus koraiensis seeds in the forest setting to analyze the differences in multiple transport events and transport distances of these seeds. Our results are as follows: 1) The consumption speed of seeds by rodents of different seed sizes is significantly different. Large seeds were consumed at the fastest rate, followed by medium seeds, and the small seeds is the slowest. 2) We observed significant differences in the situ consumption rate of different sizes of seeds by rodents. The consumption rate of small seed in situ was the highest, followed by medium seeds, and then large seeds. Moreover, the different sizes of seeds were consumed and scatter-hoarded rate after transportation by rodents, with large seeds having the highest rates followed by medium seeds, and then small seeds. However, there were no significant differences in the predation rate after seed scatter-hoarding by rodents. 3) There was a significant difference of seed hoarding distance in the first hoarding event of Pinus koraiensis seeds of different sizes. The seed hoarding distance during the first hoarding event showed significant differences among the different seed sizes. The hoarding distance between large and medium seeds was significantly greater than that for small seeds. However, no significant differences in hoarding distance were observed during the second, third, and fourth hoarding events. 4) Our observations indicated that rodents transported and cached seeds from the seed station to the nearest areas for rapid sequestration. Moreover, they removed the cached seeds from points near the seed source to more distant locations. These results support the optimal cache spacing model.

Key words: Pinus koraiensis seeds, multiple hoarding, seed size, scatter hoarding, hoarding strategy, rodent

摘要：

红松（Pinus koraiensis）主要分布于中国东北地区，松科松属常绿乔木，种子质量大，其球果成熟后种鳞不能自然张开，不能依赖水、风等媒介传播种子，主要依赖以其种子为食的啮齿动物和鸟类分散贮藏的方式传播种子。在内蒙古赤峰市旺业甸林场红松林释放不同大小的红松种子，针对啮齿动物对不同大小红松种子的取食、贮藏偏好、多次贮藏及贮藏距离的差异进行研究，探究啮齿动物对不同大小红松种子取食与贮藏的影响。结果表明，1）不同大小的红松种子原地留存动态有所不同，啮齿动物收获不同大小红松种子的速率均存在显著差异，小种子原地留存时间最长，中等大小的种子原地留存时间次之，大种子原地留存时间最短。2）啮齿动物对不同大小红松种子的原地取食率存在显著差异。原地取食率最高为小红松种子，其次为中等大小的种子，大种子原地取食率最低。不同大小红松种子搬运后取食率和贮藏率均存在显著差异，大种子搬运后取食率和贮藏率最高，其次为中等大小的种子，小种子搬运后取食率和贮藏率最低。不同大小的红松种子贮藏后取食率均无显著差异。3）啮齿动物对不同大小红松种子的贮藏距离有所不同，不同大小的红松种子第1次贮藏距离具有显著差异，大种子和中等大小的种子贮藏距离显著大于小种子贮藏距离，第2次、第3次、第4次贮藏距离无显著差异。4）啮齿动物将红松种子从种子站迅速搬运贮藏至就近区域，经过多次贮藏将种源附近贮藏点的种子搬运至更远处。研究结果支持最优贮藏空间分布假说。

关键词: 红松种子, 多次贮藏, 种子大小, 分散贮藏, 贮食策略, 啮齿动物