Departamento de Biología, Instituto de Investigación Vitivinícola y Agroalimentaria, Universidad de Cádiz, Puerto Real 11510, Spain.
Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main 60325, Germany.
Proc Natl Acad Sci U S A. 2023 Oct 31;120(44):e2302440120. doi: 10.1073/pnas.2302440120. Epub 2023 Oct 23.
Seed dispersal by frugivores is a fundamental function for plant community dynamics in fragmented landscapes, where forest remnants are typically embedded in a matrix of anthropogenic habitats. Frugivores can mediate both connectivity among forest remnants and plant colonization of the matrix. However, it remains poorly understood how frugivore communities change from forest to matrix due to the loss or replacement of species with traits that are less advantageous in open habitats and whether such changes ultimately influence the composition and traits of dispersed plants via species interactions. Here, we close this gap by using a unique dataset of seed-dispersal networks that were sampled in forest patches and adjacent matrix habitats of seven fragmented landscapes across Europe. We found a similar diversity of frugivores, plants, and interactions contributing to seed dispersal in forest and matrix, but a high turnover (replacement) in all these components. The turnover of dispersed seeds was smaller than that of frugivore communities because different frugivore species provided complementary seed dispersal in forest and matrix. Importantly, the turnover involved functional changes toward larger and more mobile frugivores in the matrix, which dispersed taller, larger-seeded plants with later fruiting periods. Our study provides a trait-based understanding of frugivore-mediated seed dispersal through fragmented landscapes, uncovering nonrandom shifts that can have cascading consequences for the composition of regenerating plant communities. Our findings also highlight the importance of forest remnants and frugivore faunas for ecosystem resilience, demonstrating a high potential for passive forest restoration of unmanaged lands in the matrix.
果实传播者是破碎景观中植物群落动态的基本功能，因为森林残余物通常嵌入在人为栖息地的基质中。果实传播者可以在森林残余物之间以及植物在基质中的定殖中起媒介作用。然而，由于具有在开阔栖息地中不太有利的特征的物种的丧失或替代，果实传播者群落如何从森林转变为基质，以及这些变化是否最终通过物种相互作用影响分散植物的组成和特征，这仍然知之甚少。在这里，我们通过使用在欧洲七个破碎景观的森林斑块和相邻基质栖息地中采样的独特种子传播网络数据集来填补这一空白。我们发现，森林和基质中对种子传播有贡献的果实传播者、植物和相互作用的多样性相似，但所有这些组成部分的周转率（更替）都很高。分散种子的周转率小于果实传播者群落，因为不同的果实传播者在森林和基质中提供了互补的种子传播。重要的是，这种更替涉及到基质中更大、更具移动性的果实传播者的功能变化，这些果实传播者传播更高、更大种子、果实成熟时间更晚的植物。我们的研究提供了一种基于特征的理解，即通过破碎景观进行果实传播者介导的种子传播，揭示了非随机的转变，这可能对再生植物群落的组成产生级联效应。我们的研究结果还强调了森林残余物和果实传播者动物群对于生态系统恢复力的重要性，表明在基质中未管理土地的被动森林恢复具有很高的潜力。
