Animals are often the primary dispersers of seeds and fungal spores. Specialist species, that consume fruits or fungal fruiting bodies (sporocarps) as their main food source, are thought to play a more important role in dispersal networks compared to generalist species. However, dispersal networks are often based on occurrence data, overlooking the influence of animal abundance and dispersal effectiveness on network interactions. Using rodent-mycorrhizal fungi networks, we determined how diet specialization and abundance influence the role of rodent species in dispersing fungal spores in temperate forests of northern New Hampshire, USA. We tracked the interactions of five rodent species and 34 fungal taxa over a three-year period across hardwood, mixed, and softwood forest stands. We accounted for fluctuations in rodent abundance and differences in the number of spores dispersed in rodent scat. Myodes gapperi, a fungal specialist, dispersed a more diverse spore community than rodent generalists and was consistently the most important disperser in forest types with high fungal availability. Nevertheless, during years when generalist species such as Tamias striatus and Peromyscus maniculatus reached high abundance, their relative importance (species strength) in networks approached or even surpassed that of M. gapperi, particularly in forest types where M. gapperi was less common and fungal availability was low. Increased numbers of generalists enhanced network interaction diversity and the number of fungal taxa dispersed, the timing of which was coincident with seedling establishment following masting, a stage when inoculation by mycorrhizal fungi is critical for growth and survival. Our findings suggest that although specialists play key roles in dispersing mycorrhizal fungal spores, generalists play a heretofore underappreciated role.

中文翻译：

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啮齿动物通才在真菌孢子传播网络中的作用被低估

动物通常是种子和真菌孢子的主要传播者。与一般物种相比，以水果或真菌子实体（孢子果）为主要食物来源的特殊物种被认为在传播网络中发挥着更重要的作用。然而，传播网络往往基于发生数据，忽视了动物数量和传播有效性对网络相互作用的影响。使用啮齿动物-菌根真菌网络，我们确定了饮食专业化和丰度如何影响啮齿动物物种在美国新罕布什尔州北部温带森林中散布真菌孢子的作用。我们在三年的时间里追踪了五种啮齿动物物种和 34 种真菌类群在硬木、混合和软木林分上的相互作用。我们考虑了啮齿动物丰度的波动和分散在啮齿动物粪便中的孢子数量的差异。真菌专家 Myodes gapperi 比啮齿动物通才分散了更多样化的孢子群落，并且一直是真菌可用性高的森林类型中最重要的分散者。然而，在通才物种（如Tamias striatus和Peromyscus maniculatus）达到高丰度的年份，它们在网络中的相对重要性（物种强度）接近甚至超过M. gapperi，特别是在M. gapperi不那么常见和真菌的森林类型中可用性很低。通才数量的增加增强了网络相互作用的多样性和真菌类群的数量分散，其时间与发芽后的幼苗建立一致，菌根真菌接种对生长和存活至关重要的阶段。我们的研究结果表明，尽管专家在散布菌根真菌孢子方面发挥着关键作用，但通才发挥的作用迄今未被充分认识。