Testing the accuracy of a Rights-of-Way pollinator habitat scoring system

Habitat loss is a major cause of pollinator declines, and there is increased interest by the public in creating pollinator-friendly lands. Electric and transportation rights-of-way (ROW) present an opportunity for large amounts of land to be managed to support pollinators. The Rights of Way as Habitat Working Group developed a pollinator habitat scorecard with the goal of establishing a consistent valuation method for pollinator habitat quality in ROWs. In this study, we tested how well the pollinator habitat score aligns with several measures of pollinator biodiversity in electric transmission ROWs. We used pan traps and timed observations to quantify the communities of lepidopterans and bee hymenopterans at 12 ROW sites in Illinois, USA. The 12 study sites were divided across four geographical locations in the greater Chicago metropolitan area, with each location including three sites managed in different ways: turf-grass lawn, restored prairie, and weedy old-field. We found that the pollinator habitat score was not a significant predictor of bee and lepidopteran pollinator biodiversity. However, the pollinator habitat score did differ significantly among the ROW management types, with lawn sites receiving lower scores than prairie or old-field sites. These results indicate that the pollinator habitat scorecard may not, in its current form, be appropriate for comparing pollinator biodiversity among sites, although it does capture differences in pollinator resource availability at a local scale. We suggest that the scorecard as currently designed may be more useful in monitoring temporal changes at individual sites rather than making spatial comparisons among sites. We also recommend that future studies continue to examine ways to make the pollinator habitat scorecard a more universally applicable tool, because an accurate, simple scorecard would provide valuable information to ROW land managers.