Restoration has positive effects on biodiversity, however it is unclear whether it improves ecosystem function – in particular ecosystem function within the restoration. Pollination is a component of function critical to plant reproductive success and could be an important determinant of restoration outcomes. Restoration of animal-mediated pollination may require consideration of factors beyond the local scale, as pollinators can be sensitive to habitat availability at the landscape level. Surrounding landscape quality may influence the abundance and diversity of pollinators and thus affect pollinator-dependent plant reproductive success within the restoration. We hypothesized increasing agriculture around prairie restorations would reduce seed set in a bee-pollinated forb. We tested this hypothesis by deploying potted Chamaecrista fasciculata (Fabaceae) at a constant population size and density to restored prairies in western Minnesota. We measured how seed production varies with proportion of surrounding agriculture between plants that receive maximum pollination (supplemental pollination; SP) and plants that only receive natural pollination (open pollination; OP). We tested for an interaction between proportion agriculture and pollination treatment using a generalized linear mixed model.
Results/Conclusions
We did not find a significant interaction between proportion agriculture and pollination treatment. Chamaecrista fasciculata plants did not exhibit a strong reduction in seed set with increasing agriculture (p-value=0.151), potentially because of the life history and behavior of its dominant pollinator. We also found no significant difference in seed set between our pollination treatments (p-value=0.562), indicating C. fasciculata was not pollen limited in our study system. Because pollen limitation is common, it may still be an important driver of reproductive success in restorations, particularly in species with self-incompatible mating systems, specialized pollination systems, or within small or low-density populations.