Data for: Pollinators maintain biodiversity in assembling plant communities

We did an experiment testing the effect of three levels of pollinator
visitation on all forb flowers in plant communities of a prairie
restoration. These pollination treatments were a pollinator exclusion
treatment, an augmented pollination treatment, or a control, and were
carried out within plots of different graminoid/forb seed ratios. The
split plot design consisted of 11 different graminoid/forb ratios applied
to 55 whole plots, and the pollination treatments were carried out in
subplots within each whole plot. We sampled seed heads of 8 common
animal-pollinated forbs to compare excluded vs. controls on number of
germinants in the seed rain in 2021 and 2022. We sampled plant diversity
within the subplots at the quadrat and subplot scale in 2023. Pollinator
exclusion treatments resulted in 50% less germinants from the seed rain,
23% lower plant species richness, and 27% lower animal-pollinated forb
richness. Also, the positive relationship between forb abundance and plant
richness seen in augmented and control subplots was eliminated with
pollinator exclusion. These results suggest that pollinator decline may be
leading to a plant-pollinator extinction vortex. This study suggests, for
the first time we are aware of, that plant biodiversity at the community
level can be limited by animal pollinators.