Wild bee declines linked to plant‐pollinator network changes and plant species introductions

Abstract

Abstract The mutualistic interactions of plant‐pollinator networks provide myriad economic, ecological, and cultural constituents without which there would be severe environmental and societal consequences. Plant‐pollinator networks are becoming increasingly vulnerable to disturbance through intensifying anthropogenic land use and climate change. Wild bees are central to pollination and documenting unique regional interactions between wild bees and floral hosts provides powerful insights into local ecology and biodiversity in addition to the potential to detect temporal network variation. This study characterises the changes in a northern New England wild bee plant‐pollinator network over the past 125 years and reveals a striking increase in exotic bee and plant taxa over time. Here we document that declining wild bee species have historic ties to threatened and endangered plant species. These data provide a rare insight into the fragile nature of plant‐pollinator networks. Notable specialist interactions between native taxa that were recorded in historical networks have been lost, most likely due to local extirpation of these now threatened and endangered plant species. Subsequent monitoring and conservation efforts focused on habitat restoration for declining wild bee and plant taxa are fundamental to the future preservation of regional native diversity.