Effects of fire severity on the floral visitor community, pollination, and reproduction of a dominant flowering sub-alpine shrub

Anthropogenic climate change has influenced fire regimes globally and recent fires in Colorado are burning at a severity not seen in the past 700 years. Climate change is driving extreme weather conditions that will likely continue to generate more fires with lasting effects on biological communities and the ecosystem services they provide. The Rocky Mountains have locations that are recovering from mixed severity wildfires that burned ~20 years ago, which can help us understand how native bees are impacted long-term by fire severity and how that could affect plant pollination. To determine how fire severity impacted visitation and pollination of a dominant flowering shrub, we sampled the community of native bees foraging on wax currants (Ribes cereum) throughout the flowering season in high severity, low severity, and unburned sites. By comparing abundance and diversity of native bees visiting R. cereum, we determined direct effects of fire on bee communities and the mechanisms driving differential impacts of fire severity on native bees. We also conducted a pollinator exclusion experiment using R. cereum to compare effects of pollination services across fire severities. Understanding the role of native bees in providing pollination services and how fire severity impacts interactions can help identify long-term impacts of fire on plant-pollinator interactions. There is limited information on how native bees are impacted by fire and how that subsequently impacts pollination services, this study bridges an ecological gap in our understanding of long-term impacts of fire on ecosystem services within the Rocky Mountain region.