D3068: (1st Place) Effects of wildfire burn severity on wild bee communities two decades post-fire

Anthropogenic factors such as fire suppression, land-use, and climate change are changing wildfire regimes globally. While fire is a natural disturbance in many global ecosystems, changes in fire frequency, severity, and seasonality can affect multiple trophic levels of an ecosystem, including insect pollinators. Wild bee (Hymenoptera: Apoidea: Anthophila) populations are decreasing globally due to climate change, disease, habitat fragmentation and land use change. Disturbances like wildfire affect wild bee communities, but recent meta-analyses are conflicted about whether fire harms or benefits bees.



We investigated the effects of wildfire burn severity on native bee abundance and diversity across different burn severities in two-mixed severity fires in ponderosa pine, Pinus ponderosa, forest that burned >20 years ago. We also evaluated whether bee diversity and abundance correlated with floral resource availability across burn severities, measured as the diversity and abundance of flowering plant species at our various study sites. We also recorded all plant species that we observed bees visiting so that we could assess bee-plant interactions. Our work helps to fill a knowledge gap in the study of disturbances and their impact on insect pollinator communities by studying fire sites that burned more than two decades ago. Our research provides insight into how wildfire might affect wild bee communities during long-term, post-fire forest recovery.