Abundance and richness of ground nesting bees and wasps increases with fire frequency in Florida longleaf pine flatwoods

Ground-nesting bees and wasps are critical pollinators in southeastern longleaf pine flatwoods. Longleaf pine flatwoods have one of the shortest burn regimes of any pine forest, but optimal fire frequency management for ground-nesting pollinators in this ecosystem is still unknown. This study examined how ground-nesting bees and wasps are affected by fire frequency. Research took place in a long-term experiment within a Northern Florida longleaf pine flatwood, with three fire frequencies (1, 2, and 4 years) and an unburned control. We used soil emergence traps to assess bee and wasp nesting rates, and hand netting from flowers to assess bee and wasp foraging rates. A diversity of taxa belonging to 3 genera of bees and 17 genera of pollinating wasps were found in emergence traps. 15 genera of foraging bees were found. Results show more bees in emergence traps in 1 and 2 year burn treatments than in 4 year and unburned controls. However, bee richness and wasp abundance and richness were higher in all three burn treatments compared to unburned controls. Foraging bees were most abundant in unburned controls but had higher richness in 2 and 4 year burn treatments compared to 1 year burn treatments and unburned controls. This suggests that ground-nesting pollinators, especially bees, require frequently burned areas for nesting but may benefit from a variety of fire frequencies for foraging.