Li Ning, Yang Xifu, Ren Yuanhao, Wang Zheng
Institute of Applied Ecology, Nanjing Xiaozhuang University, Nanjing, China.
State Key Laboratory of Integrated Management of Pest Insects and Rodents in Agriculture, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
Front Plant Sci. 2022 Sep 21;13:1010352. doi: 10.3389/fpls.2022.1010352. eCollection 2022.
Although mutualistic network analyses have sparked a renewed interest in the patterns and drivers of network structures within communities, few studies have explored structural patterns within populations. In an endangered tree species population, plant individuals share their bird seed dispersers; however, the factors affecting individual interaction patterns are poorly understood. In this study, four individual-based networks were built for the endangered Chinese yew, , in a fragmented forest based on bird foraging type (swallowing and pecking networks) and habitat type (networks in a bamboo patch and an evergreen broad-leaved forest patch). Species-level network metrics (species degree and specialization, ) were used to evaluate the effects of species traits (bird and plant traits) on species-level networks and dispersal distance for . It was revealed that the interaction networks between individuals and their bird partners were influenced by foraging type and the habitat of plant distribution. Compared to the other two networks, bird swallowing and bird-fruit networks in the evergreen broad-leaved patch habitat had higher nestedness and connectance but lower modules and specialization. Bird (body weight and wing and bill lengths) and plant traits (height, crop size, and cover) significantly affected species-level network metrics such as degree and specialization. Furthermore, seed dispersal distance was influenced by species traits and the species-level metrics of fruit-bird interaction networks. These results provide new insights into individual-based seed dispersal mutualistic networks of endangered plant species under habitat fragmentation. Moreover, these findings have relevant implications for conserving and managing individual endangered trees in increasingly disturbed ecosystems.
尽管互利网络分析重新激发了人们对群落内部网络结构模式及其驱动因素的兴趣，但很少有研究探讨种群内部的结构模式。在一个濒危树种种群中，植物个体共享它们的鸟类种子传播者；然而，影响个体相互作用模式的因素却鲜为人知。在本研究中，基于鸟类觅食类型（吞咽和啄食网络）和栖息地类型（竹林斑块和常绿阔叶林斑块中的网络），为破碎化森林中的濒危红豆杉构建了四个基于个体的网络。使用物种水平的网络指标（物种度和专业化程度等）来评估物种特征（鸟类和植物特征）对物种水平网络的影响以及红豆杉的传播距离。结果表明，红豆杉个体与其鸟类伙伴之间的相互作用网络受觅食类型和植物分布栖息地的影响。与其他两个网络相比，常绿阔叶林斑块栖息地中的鸟类吞咽和鸟果网络具有更高的嵌套性和连通性，但模块性和专业化程度较低。鸟类特征（体重、翅长和喙长）和植物特征（高度、果序大小和覆盖度）显著影响物种水平的网络指标，如度和专业化程度。此外，种子传播距离受物种特征和果鸟相互作用网络的物种水平指标的影响。这些结果为栖息地破碎化下濒危植物物种基于个体的种子传播互利网络提供了新的见解。此外，这些发现对日益受到干扰的生态系统中濒危树木个体的保护和管理具有相关意义。
