MOE Key Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China.
State Key Laboratory of Integrated Management of Pest Insects and Rodents in Agriculture, Institute of Zoology, Chinese Academy of Sciences (CAS), Beijing, China.
Integr Zool. 2021 Jan;16(1):109-119. doi: 10.1111/1749-4877.12475. Epub 2020 Aug 4.
Density-dependent non-monotonic species interactions are important in maintaining ecosystem stability and function, but empirical evidences are still rare. Rodents, as both seed dispersers and seed predators, have dual effects on plant regeneration and may result in non-monotonic rodent-plant interactions. According to the non-monotonic models, the relative positive or negative effects of rodents on seedling establishment can be measured based on the positive or negative association of seedling recruitment rate and rodent abundance. In this study, we investigated the fates of acorns of Quercus serrata by tracking tagged seeds on 21 fragmented subtropical islands in the Thousand Island Lake, China. We found that the proportion of germinated seeds of all released seeds showed a dome-shaped association with rodent abundance per seed. The proportion of removed seeds and cached seeds showed a saturated- and a weak dome-shaped association with rodent abundance per seed, respectively. Our results demonstrated a clear empirical evidence that rodent abundance per seed triggered a switch between the relative mutualism and predation in a rodent-seed system. Our study implied that the observed non-monotonic interactions between plants and animals may play a significant role in maintaining biodiversity and ecosystem function. We appeal for more investigations of the complex non-monotonic interactions in various ecosystems.
密度依赖的非单调种间相互作用对于维持生态系统的稳定性和功能非常重要，但经验证据仍然很少。啮齿动物既是种子传播者又是种子捕食者，对植物再生有双重影响，可能导致啮齿动物与植物的相互作用呈非单调变化。根据非单调模型，可以根据幼苗建立率和啮齿动物丰度的正或负关联来衡量啮齿动物对幼苗定植的相对正或负影响。在这项研究中，我们通过在千岛湖的 21 个破碎化的亚热带岛屿上追踪标记种子，研究了麻栎栎属橡子的命运。我们发现，所有释放种子的发芽种子比例与每粒种子的啮齿动物丰度呈圆顶形关联。被去除的种子和被储存的种子的比例与每粒种子的啮齿动物丰度呈饱和和弱圆顶形关联。我们的研究结果提供了一个明确的经验证据，表明每粒种子的啮齿动物丰度引发了啮齿动物-种子系统中相对共生关系和捕食关系之间的转换。我们的研究表明，在动植物之间观察到的非单调相互作用可能在维持生物多样性和生态系统功能方面发挥重要作用。我们呼吁在各种生态系统中对复杂的非单调相互作用进行更多的研究。
