Fricke, E. C. | Search bioRxiv

bioRxiv2024

Seed dispersal disruption limits tropical forest regrowth

Many trees depend on animals for seed dispersal, and human activities that disrupt seed dispersal by animals may impact forest regeneration and carbon storage. Yet whether expected negative impacts are observable across regrowing forests remains untested. We modeled seed dispersal disruption and its relationship to aboveground carbon accumulation observed across 3026 sites in the tropics, where most trees are animal dispersed. We found that seed dispersal disruption explains wide variation in local carbon accumulation rates. Across areas identified for restoration, we estimate that seed dispersal disruption reduces carbon accumulation rates by 57% on average. These results advance understanding of animal biodiversitys impact on forest carbon and emphasize the need to address biodiversity loss and climate change together.

ecology↗

bioRxiv2021

Frugivore gut passage increases seed germination: an updated meta-analysis

Many plants rely on animal mutualists for reproduction. Quantifying how animal mutualists impact plant performance provides a foundation for modelling how change in animal communities affects the composition and functioning of plant communities. We performed a meta-analysis of 2539 experiments, 6 times more than the last comprehensive meta-analysis, examining how gut passage by frugivores influences seed germination. We simultaneously analyzed multiple predictor variables related to study methodology, location, and frugivore identity to disentangle methodological from ecological impacts on effect sizes. We found that gut passage by birds, fish, reptiles, bats, primates, and other mammals on average increased seed germination, but that the magnitude varied across vertebrate groups. The positive effects of gut passage were largely explained by the de-inhibitory effects of pulp removal rather than by the scarification of seed tissues. Some previous studies and meta-analyses that found no effect of gut passage only tested scarification or did not distinguish between these tests of scarification and pulp removal. We found that, for a typical fleshy-fruited plant species, the lack of gut passage reduces germination by 60%. From an evolutionary perspective, this indicates a large risk associated with reliance on animal mutualists that is balanced against the benefits of animal-mediated seed dispersal. From a conservation perspective, this highlights the potential for large demographic consequences of frugivore declines on plant populations. Our database and findings advance quantitative predictions for the role of fruit-frugivore interactions in shaping plant communities in the Anthropocene.

ecology↗