Wildfire risk reduction and pollinators: Effects of logging and prescribed fire on pollinator communities, habitat, and plant-pollinator mutualisms in the Northern Rocky Mountains

Insect pollinators are essential for the maintenance of biodiversity and functioning of ecosystems. Pollinators sustain healthy vegetation communities by facilitating reproduction of plants through the transfer of pollen between conspecific individuals. Without pollinators, it is estimated that half of flowering plant species would suffer more than and 80 percent reduction in seed production and a third would produce no seeds. By sustaining healthy plant communities, pollinators promote soil health and stability, water quality, nutrient availability, and the aesthetic value of public lands. Insects that pollinate plants include flies, wasps, butterflies, beetles, and moths, but bees are the most effective pollinators because they actively collect pollen and nectar as their primary food source. However, global declines of bees , butterflies, and other flying insects threaten the delivery of pollination services in wild and agro-ecosystems. Beyond the direct effects of pollinator diversity for ecosystem function, pollinators are charismatic and culturally significant species that have intrinsic value worth protecting.

Additionally, pollinator declines, habitat loss, and habitat fragmentation often lead to a loss of mutualistic interactions such as plant-pollinator relationships. Some studies have shown that landscape change such as deforestation affects the structure of mutualistic networks. The structure of plant-pollinator networks is important because it can tell us about the quantity and quality of pollinator services, community flexibility and resilience to disturbance, as well as give insight to restoration and management plans. The recent widespread declines in bee populations created an urgent need and interest to manage and protect insect pollinators and the services they provide. For example, a Presidential Memorandum tasked federal agencies with promoting bee health across the U.S., and many National Forests have included desired conditions and goals for maintaining and restoring bee habitat in their revised forest plans. However, successful management is hindered by lack of information about how common land management practices affect pollinators and pollinator habitat through time. A recent review of public land management effects on pollinators found relatively few studies on this topic. Most of the few studies were conducted in the eastern U.S., and none examined plant- pollinator networks.

We propose to determine the effects of logging and prescribed burning on pollinator communities, pollinator habitat, and plant-pollinator mutualistic networks in coniferous forests in the Northern Rocky Mountains. This study will be the first to examine how these common treatments affect pollinators in conifer forests of western North America. This information is urgently needed given the Forest Service’s Wildfire Crisis Strategy which will treat (primarily with logging and burning) up to 50 million acres over the next 10 years, mostly in the western U.S. Importantly, several western bumble bee species are severely declining and could be listed soon under the Endangered Species Act. If listed, information about the effects of logging and burning on these species would be critical for continuing treatments in regions where these species occur.