Species temporal persistence promotes the stability of fruit–frugivore interactions across a 5‐year multilayer network

• Published in: The Journal of ecology Vol. 108; no. 5; pp. 1888 - 1898
• Main Authors: Costa, José M., Ramos, Jaime A., Timóteo, Sérgio, Silva, Luís P., Ceia, Ricardo S., Heleno, Ruben H., Bartomeus, Ignasi
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Publishing Ltd 01.09.2020
• Subjects: Abundance; Birds; community stability; Community structure; Dispersal; Dispersion; ecological networks; frugivory; Herbivores; interaction persistence; Interlayers; Links; Migratory birds; Modular structures; Multilayers; multitrophic interactions; Network topologies; Plant species; plant–animal mutualisms; Relative abundance; Rewiring; Seed dispersal; Seeds; Species; Stability; Structural analysis; temporal dynamics; Topology
• ISSN: 0022-0477; 1365-2745
• DOI: 10.1111/1365-2745.13391

Biological communities are intrinsically dynamic, with species and interactions changing over time. However, the temporal dynamics of species interaction networks is usually assessed using independent ‘snapshot’ networks, which may provide an incomplete representation of ecological processes. The use of temporal multilayer networks, where networks (i.e. layers) are formally interconnected via interlayer links, can circumvent such limitation, allowing for a more realistic characterization of community structure and better predictions regarding long‐term processes that rely on species interactions, such as seed dispersal. We used a 5‐year bird–seed dispersal dataset to explore species and interaction turnover across years, network structure variability and the relationship between species topological roles on each year and their temporal persistence (i.e. species activity). We then implemented a temporal multilayer network approach to compute overall species versatility (centrality) and to reveal the modular structure of the 5‐year multilayer network using changes in species relative abundances as proxies for the interlayer links between time‐sequential networks. Network topology remained relatively constant across years and interaction turnover was mostly due to true rewiring (new links) between species. Overall, birds, some of which migratory, were temporally more reliable than fleshy‐fruited plants. Interestingly, species present across more years tended to be more important to the structure of each years' seed dispersal network, independently of their relative abundance. The multilayer analysis identified four modules of tightly interacting species, all of which spanning across the 5 years, and with a greater stability in the composition of bird species when compared to plants. Synthesis. Bird and plant species that are present in more years in the seed dispersal network were also disproportionally important in each year, forming a core of temporally reliable interacting partners for transient species in the network. We combined a classical monolayer with a multilayer approach to study the interannual dynamics of a bird–seed dispersal network. This network was structured in four interaction modules spanning across the 5 years of the study. Bird and plant species that are present in more years in the network were also disproportionally important in each year, forming a core of temporally reliable interacting partners for transient species in the network.