The global decline in pollinators due to land-use change and habitat fragmentation has led to concern about pollination dynamics within human-modified landscapes. Pollination dynamics can be impaired pre-dispersal, post-dispersal, and during pollen transport. To address the question of how management of modified landscapes impact pollination dynamics, we quantified percent pollen viability and amount of fruit set by goldenrod Solidago canadensis within powerline corridor and managed old-field landscapes. We also counted the number of bumblebees Bombus impatiens visiting goldenrod patches within disturbed areas of the two landscapes. Powerline corridors are managed to maintain early-successional habitats and thereby prevent vegetation interference with electricity transmission lines. The old-field sites studied are maintained to create openings for wild turkey management. We tested the hypothesis that goldenrod patches within the managed old-field landscape, which has an annual disturbance regime, would have fewer pollinators compared to the powerline corridor, which has a 5 to 7-year disturbance regime.
Results/Conclusions
We observed that annual mowing of the old-field sites facilitated recolonization by other insect-pollinated plants, which meant that they experienced more pollinator visits. Pollen viability and amount of fruit set did not differ between the two landscapes, suggesting that pollination dynamics in the two landscapes is impacted primarily at the dispersal phase. These findings suggest a positive feedback between frequency of disturbance and pollinator density. We conclude that management of human-modified landscapes should focus on promoting a variety of floral resources, as patches with more diverse wildflower community tend to attract more pollinators.