埋藏点深度、间距及大小对花鼠发现向日葵种子的影响

Effects of soil depth,cache spacing and cache size of sunflower(Helianthus annuus)seeds on seed discovery by Siberian chipmunk(Tamias sibiricus senescens)

2005年5～6月,在北京东灵山地区,通过在实验围栏内设置不同深度、间距和大小的埋藏点,研究了花鼠对向日葵种子的发现率。结果表明,花鼠发现埋藏种子的比例随埋藏深度的增加而减少,埋藏深度>5cm后,发现比例较低,且不再有明显变化;花鼠发现埋藏种子的比例随埋藏点间距的减小而增加,埋藏点间距<0.5m后,发现比例较高,且不再有明显变化;花鼠发现埋藏种子的比例随着埋藏点增大而增加,埋藏点种子>5g后,发现比例较高,且不再有明显变化。

We conducted three experiments during May - June, 2005, to study the effects of artificial depth of placement, cache spacing, and cache size of sunflower （ Helianthus annuus Linn. ） seeds on seed discovery by Siberian chipmunks （Tamias sibiricus senescens） in the Dongling Mountains, northwestern Beijing, China. We found that the proportions of seeds discovered were negatively correlated with depth from the soil surface, were extremely low, and but did not differ when seeds were buried at 5 - 8 cm vs. ≥ 10 cm depths. Proportions of seeds discovered were negatiyely correlated with distance between caches, with caches spaced at 1.5 m intervals discovered significantly less often than those spaced more closely together. Proprotions of seeds discovered were positively correlated with cache size, with caches of 1 g found less often than caches of larger size.