Fire frequency and timing influence bee–flower interactions: a case study from an oak‐pine savanna restoration on the Cumberland Plateau

Abstract

Abstract Introduction Native plant communities have declined in the southeastern United States over the past century because of habitat loss and fire suppression. While restoration of these communities often requires prescribed fire, the effects of fire on endemic insects remain unclear. Pollinators of savanna plants, including bees, are an important group to study in restoration contexts. Fire timing and frequency may impact both plant composition and plant‐bee interactions. Objectives We studied the influence of fire timing (early and late growing‐season) and frequency (1‐, 2‐, and 3‐year fire‐return interval) on plant‐bee interactions. Methods As a case study, we surveyed plants, plant flowering, and plant‐bee interactions across different long‐term vegetation management fire treatments in an oak‐pine savanna on the Cumberland Plateau, Tennessee in 2023. Results Fire frequency influenced greater forb coverage in the 1‐ and 2‐year fire‐return interval treatments and greater woody coverage in the 3‐year fire‐return interval treatments. Continual burning during the early growing‐season (EGS) on a 2‐year interval over 15 years led to greater grass coverage and reduced floral resources except when compared to the EGS 3‐year unit. Increased grass coverage led to decreased floral resources in the EGS 2‐year treatment compared to the late growing‐season (LGS) 1‐year treatment. Similarly, we observed an increased number of plant‐bee interactions in the 1‐year LGS treatment relative to the 2‐ and 3‐year EGS treatments. Conclusions A 1‐ or 2‐year fire‐return interval was required to maximize floral abundances, and burning during the late growing season is preferable to maximize floral resource availability.