Species-specific interactions in avian–bryophyte dispersal networks

Abstract

Studies from seed plants have shown that animal dispersal fundamentally alters the success of plant dispersal, shaping community composition through time. Our understanding of this phenomenon in spore plants is comparatively limited. Though little is known about species-specific dispersal relationships between passerine birds and bryophytes, birds are particularly attractive as a potential bryophyte dispersal vector given their highly vagile nature as well as their association with bryophytes when foraging and building nests. We captured birds in Gifford Pinchot National Forest to sample their legs and tails for bryophyte propagules. We found 24 bryophyte species across 34 bird species. We examined the level of interaction specificity: (i) within the overall network to assess community level patterns; and (ii) at the plant species level to determine the effect of bird behaviour on network structure. We found that avian–bryophyte associations are constrained within the network, with species-specific and foraging guild effects on the variety of bryophytes found on bird species. Our findings suggest that diffuse bird–bryophyte dispersal networks are likely to be common in habitats where birds readily encounter bryophytes and that further work aimed at understanding individual bird–bryophyte species relationships may prove valuable in determining nuance within this newly described dispersal mechanism.

Passive directed dispersal of plants by animals

“…In others, animal procurement of resources generates favourable plant conditions via biopedturbation. The necessary conditions for passive directed dispersal may also be present in additional plant–dispersal relationships for which requisite evidence is not yet established (Hernández‐Brito et al ., 2021; Chmielewski & Eppley, 2022).…”

Dispersal mediates trophic interactions and habitat connectivity to alter metacommunity composition

“…Dispersal is a fundamental process shaping community diversity, abundance, and composition (Chmielewski & Eppley, 2022;Jønsson et al, 2016;Vellend, 2010).…”

“…Dispersal is a fundamental process shaping community diversity, abundance, and composition (Chmielewski & Eppley, 2022; Jønsson et al, 2016; Vellend, 2010). Dispersing individuals leave their natal habitat patch and may rescue populations in other patches (Brown & Kodric‐Brown, 1977; Thompson et al, 2020) or colonize/recolonize unoccupied patches (Denk & Hallatschek, 2022; Jønsson et al, 2016), provided they can disperse far enough to access them (Ponisio et al, 2019).…”