Management Affects Pollinator Biodiversity and Function in Suburban Green Spaces

Background/Question/Methods

Research suggests that managed urban green spaces, such as powerline corridors and residential yards, may serve as pollinator habitat, depending on their vegetation management. In the Chicago metropolitan area, some powerline corridors are actively managed with mowing and herbicide (“mowed corridors”), while others are managed passively by planting native prairie plants (“prairie corridors”), and some are rarely managed and therefore overgrown (“oldfield corridors”). We examined the species composition and functional diversity of the insect pollinator communities found in mowed, oldfield, and prairie corridors, as well as residential backyards paired with these corridors in suburban Chicago. Data were collected on behavioral and morphological effect traits, which we used to determine functional diversity metrics (functional richness, evenness, divergence, and dispersion) and community weighted means of the pollinator community in each corridor. We analyzed differences in the pollinator community between the three types of vegetation management and yards using generalized linear models. We also performed a sentinel plant assay with cucumbers (Cucumis sativus) to measure the quantity and quality of pollination facilitated by these insects.

Results/Conclusions

Prairie and oldfield corridors demonstrated higher abundance, Shannon diversity, and functional diversity of pollinators than either yards or mowed corridors. Pollination was also highest in prairie and oldfield corridors, with residential yards demonstrating greater pollination function than mowed corridors. We conclude that powerline corridors provide ecological value to the suburban landscape by serving as pollinator habitat within the surrounding urban matrix. We recommend that powerline companies and municipal planners consider the pollinator habitat quality of powerline corridors when making management decisions.