Seed-dispersal interactions in fragmented landscapes – a metanetwork approach

Mutualistic interactions repeatedly preserved across fragmented landscapes can scale-up to form a spatial metanetwork describing the distribution of interactions across patches. We explored the structure of a bird seed-dispersal (BSD) metanetwork in 16 Neotropical forest fragments to test whether a distinct subset of BSD-interactions may mediate landscape functional connectivity. The metanetwork is interaction-rich, modular and poorly connected, showing high beta-diversity and turnover of species and interactions. Interactions involving large-sized species were lost in fragments < 10 000 ha, indicating a strong filtering by habitat fragmentation on the functional diversity of BSD-interactions. Persistent interactions were performed by small-seeded, fast growing plant species and by generalist, small-bodied bird species able to cross the fragmented landscape. This reduced subset of interactions forms the metanetwork components persisting to defaunation and fragmentation, and may generate long-term deficits of carbon storage while delaying forest regeneration at the landscape level.

This work was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (BIOTA/FAPESP 2014/01986‐0). CE received a FAPESP postdoctoral fellowship (2015/15172‐7, 2016/18355‐8). MAP and MG received fellowships from Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). PJ was supported by Severo Ochoa Excellence Award (SEV‐2012‐0262) and Programa Ciência Sem Fronteiras (CNPq, PVE‐401258/2012). PRG was supported by FAPESP (2017/08406‐7). AP and SBMR were supported by SISBIOTA network – Top Predators Project (FAPESP, 2010/52315‐7) and CNPq (563299/2010‐0).