Lower diversity of forbs in prairie restoration alters pollinator communities but not structural characteristics of plant-pollinator networks

Reestablishment of native plant communities is often the primary focus of ecological restoration. This is especially true for prairie restoration, which often struggles to establish diverse forb communities. An often-overlooked component in plant reestablishment is pollinators, with 85% of forbs requiring pollination for seed reproduction. A deeper understanding of the relationship between plant and pollinator communities could improve prairie restoration success. Our goal was to determine if prairie restoration is successfully reestablishing forb and pollinator communities and their interactions by measuring plant-pollinator networks. We hypothesized that both forb and pollinator communities would be less diverse and abundant in restoration sites compared to intact prairie remnants, and that as a result, plant-pollinator networks in restoration sites would have higher nestedness and connectance, but lower modularity and network specialization than remnant sites. To test this, we measured plant-pollinator networks and forb communities from June to September 2020 at three restored and three remnant Palouse Prairie sites in eastern Washington, United States. We found that although restored sites had lower species richness of forbs and pollinators and different community composition, forb and pollinator abundance was comparable between treatments. Forb abundance in restored sites was equivalent to prairie remnants due to the presence of invasive forbs. However, these differences in community composition and diversity did not appear to impact network metrics including nestedness, connectance, modularity, and network specialization, which were similar between remnant and restored sites. Our results suggest that the structural characteristics of plant-pollinator networks can be maintained by different plant communities.