2nd Place: Butterflies and bees in unlikely landscapes: Patterns of roadside pollinator diversity in southern Idaho

Pollinating insects provide vital ecosystem services and are facing global declines and habitat loss. As undeveloped land becomes increasingly scarce, much focus has recently been directed to roadsides as potential targets for enhancing pollinator habitat. Understanding which roadsides are attractive to pollinators—and why—is essential to helping locate and prioritize pollinator conservation efforts across expansive roadside networks. To aid in this understanding, we describe our assessment of butterfly and bee diversity and abundance on a set of 63 stratified randomized roadside transects in Idaho’s Snake River Plain. Our research evaluates pollinator diversity as a function of highway class (interstate, U.S., and state highways), remotely sensed NDVI values (a measure of vegetation greenness), floral resources, and adjacent land uses. We found that highway class, NDVI, and floral richness and abundance were all significantly related to bee richness and abundance, with smaller highways and lower (less green) maximum NDVI values associated with more bee species and total bees. We also found that along interstate and state highways, lower (less green) maximum NDVI values were associated with higher butterfly species richness. Roadsides bordering sagebrush habitats typically had low NDVI values and higher bee and butterfly species richness, potentially contributing to this observed pattern. Our findings underscore the importance of preserving native sagebrush habitat in roadsides and of using pollinator-conscious roadside vegetation management practices. With this context, we weigh the potential costs and benefits of roadside habitat and consider where, when, and under what management conditions roadsides may benefit or harm pollinators.