Hou Xiang, Zhang Bo, Steele Michael A, Han Ning, Feng Tuo, Wang Jing, Chen Xiaoning, An Xiaolei, Chang Gang
Shaanxi Key Laboratory for Animal Conservation, Shaanxi Institute of Zoology, Xi'an, China.
School of Biomedicine and Food Engineering, Shangluo University, Shangluo, China.
Integr Zool. 2021 Nov;16(6):939-954. doi: 10.1111/1749-4877.12596. Epub 2021 Oct 27.
Animal-mediated seed dispersal is an important ecological process in which a strong mutualism between animals and plants can arise. However, few studies have examined how a community of potential seed dispersers interacts with sympatric seed trees. We employed a series of experiments in the Qinling Mountains in both semi-natural enclosure and the field to assess the interactions among 3 sympatric rodent species and 3 Fagaceae tree seeds. Seed traits all showed similar tannin levels but markedly different physical traits and nutritional contents. We found that seeds with heavy weight, thick coat, and high nutritional contents were less likely to be eaten in situ but more often to be eaten after dispersal or hoarded by rodents. These results support both the handling time hypothesis and the high nutrition hypothesis. Surprisingly, we also found that rodents, maybe, preferred to consume seeds with low levels of crude fiber in situ, and to harvest and hoard those with high levels of crude fiber for later consumption. The sympatric rodent species, Cansumys canus, the largest rodent in our study, harvested and hoarded more Quercus variabilis seeds with high physical and nutritional traits, while Apodemus draco, the smallest rodent, harvested more Q. serrata seeds with low physical and nutritional traits, and Niviventer confucianus harvested and hoarded more Q. aliena seeds with medium physical and nutritional traits. Our study demonstrates that different seed traits play different roles in influencing the seed fate and the shaping of mutualism and predation interactions within a community of rodent species.
动物介导的种子传播是一个重要的生态过程，在此过程中动植物之间可能会形成强烈的共生关系。然而，很少有研究探讨潜在种子传播者群落如何与同域分布的种子树相互作用。我们在秦岭的半自然围栏和野外进行了一系列实验，以评估三种同域分布的啮齿动物物种与三种壳斗科树木种子之间的相互作用。种子的单宁水平相似，但物理特性和营养成分明显不同。我们发现，重量大、种皮厚且营养成分高的种子在原地被吃掉的可能性较小，但在被啮齿动物传播或贮藏后更常被吃掉。这些结果支持了处理时间假说和高营养假说。令人惊讶的是，我们还发现，啮齿动物可能更喜欢在原地食用粗纤维含量低的种子，而收获并贮藏粗纤维含量高的种子以供日后食用。同域分布的啮齿动物中华姬鼠是我们研究中最大的啮齿动物，它收获并贮藏了更多具有高物理和营养特性的栓皮栎种子，而最小的啮齿动物中华姬鼠收获了更多具有低物理和营养特性的麻栎种子，社鼠收获并贮藏了更多具有中等物理和营养特性的辽东栎种子。我们的研究表明，不同的种子特性在影响种子命运以及啮齿动物群落内共生和捕食相互作用的形成中发挥着不同的作用。
