LB 37-315 - Floral resources mediate plant-pollinator-predator interactions in experimentally restored prairies

The goal of ecological restoration is to promote biodiversity and ecosystem functioning long term, but restoration practices often only prioritize the restoration of the plant community. However, species interactions, such as plant-arthropod interactions, are important for ecosystem functioning and the long-term success of restoration. Although prioritizing restoration of the plant community may lead to the restoration of higher trophic levels, success is highly variable and may depend on other factors, such as resource availability or other biotic interactions. Here, we considered how restoration practices aimed towards promoting plant diversity affect floral resources, then evaluate the bottom-up effects of floral resources on plant-pollinator-crab spider interactions. We worked in 12 prairies in Michigan that were experimentally restored to manipulate seed sowing richness, with half of each prairie seeded with 12 species and half seeded with 70 species. We surveyed floral richness and abundance, plant-pollinator interactions, and plant-Misumena vatia (goldenrod crab spider) interactions, asking: (1) Does seed sowing richness in prairie restoration affect floral resources? (2) How do floral resources affect M. vatia abundance and prey capture? (3) How do floral resources and M. vatia abundance affect plant-pollinator networks? (4) Are pollinators and M. vatia interacting with floral resources similarly across low and high-diversity seed sowing?We found that seed sowing richness did not affect floral richness or abundance. Floral abundance, however, did increase both plant-M. vatia interactions and plant-pollinator interactions. M. vatia individuals were also more likely to be observed with prey at sites with higher floral abundances, potentially due to the increased number of pollinator visitors at these sites. Plant-pollinator network connectance decreased with floral richness, but no other measure of network structure was affected by floral resources or M. vatia abundance. We also found that pollinators and M. vatia individuals were interacting with different floral assemblages, suggesting that these two groups are using floral resources differently in restoration. Overall, our results suggest that higher trophic level interactions may not be reliably restored by plant-focused restoration strategies, and other factors, such as floral resource availability, should also be considered for restoration of plant-arthropod interactions.