Do powerline rights-of-way impact pollinator diversity?

With the decline of pollinators worldwide, powerline rights-of-way (ROWs) have the potential to provide additional habitat to support pollinator populations. Powerline ROWs are established through clearing of tree canopy cover and woody fuels, providing open strips that contain flowering plants that provide important resources for pollinators. We sampled plants and pollinators on Salt River Project powerline ROWs across three vegetation types in Arizona: ponderosa pine forest, pinyon-juniper woodlands (PJ), and Sonoran Desert. Our aim was to determine how pollinator habitat varied on and off the ROW as well as - between vegetation types. We collected data at 27 sites in spring to early fall over three years from 2021 to 2023. Each site contained two 50m transects, one located beneath and perpendicular to the powerline (on-ROW) and another beginning 25 meters into the adjacent natural area (off-ROW). We found that plant richness and abundance were higher on powerline ROWs than in adjacent natural areas within the ponderosa pine forest vegetation type but not within PJ woodlands or Sonoran Desert. Pollinator richness and abundance followed the same pattern, with higher richness and abundance on-ROW than off-ROW in the ponderosa pine forest but not the PJ woodlands or Sonoran Desert. Richness and abundance of both plants and pollinators also varied by sampling season and year. The results of this study will be able to assist ROW managers for in maximizing pollinator resources on powerline ROWs even as they meet their other management objectives.