Date of Award
Doctor of Philosophy (PhD)
Eric L. Walters
Daniel J. Barshis
Tatyana A. Lobova
Tomás A. Carlo
Plant-animal mutualisms are a foundational component of biodiversity in terrestrial ecosystems. Most tropical forest plants have adapted to produce fleshy fruits to attract frugivorous animals to disperse seeds. Interaction patterns among plant taxa and their seed dispersers are driven by a complex suite of factors involving their evolutionary history and environmental context, and the structure of these mutualistic networks are theoretically tied to their ecological function. I carried out a series of field studies to investigate the temporal dynamics of mutualistic interactions of plant and avian frugivore communities in the central Dominican Republic and how their characteristics affect seed dispersal in agricultural landscapes. I first investigated the effects of reproductive phenology of a tropical tree (Guarea guidonia) on the temporal variation of avian foraging behavior and seed dispersal patterns. I found that temporal variation in seed dispersal was driven most by landscape-level dynamics in the availability of alternative resources rather than tree– or neighborhood–level fruit production. I proceeded to expand my focus on the processes of frugivory and seed dispersal by monitoring the phenology of six local communities and characterizing the temporal dynamics of plant-frugivore networks across a full annual period. By applying multilayer network analyses, I identified a tendency of birds to shift between temporally defined modules in nonrandom patterns that suggest a prevailing influence of resource partitioning on consumer preferences across seasonal time periods. By systematically sampling seed dispersal at a subset of these monitoring sites, I demonstrated how frugivory measures from network data predict their dispersal potential and ability to colonize new patches in heterogenous landscapes. Finally, I applied network data from frugivorous bird species to design an experiment to test the effect sounds of frugivore taxa with varying degrees of fruit consumption on the movement behavior and use of artificial perches in abandoned pastures by potential seed dispersers, finding that frugivorous bird sounds stimulate an increase in the frequency of avian visitors to degraded habitat. Collectively, my investigations provide insight into the processes of frugivory and seed dispersal in a previously undocumented region and reveal how interaction patterns can translate to ecological outcomes.
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Schubert, Spencer C..
"Temporal Dynamics and Seed Dispersal in Plant-Frugivore Communities of the Dominican Republic"
(2022). Doctor of Philosophy (PhD), Dissertation, Biological Sciences, Old Dominion University, DOI: 10.25777/gz4x-mt43