Timing of prescribed burns impacts plant diversity but not investment in pollinator recruitment in a tallgrass prairie

Prescribed burns replicate the historic fires that played a key role in maintaining prairies. Spring‐applied burns are commonly employed for grazing and brush control and, therefore, much is known about their effects. However, prairie plants may be sensitive to the historically variable timing of burns and thus differentially respond to when prescribed burns are applied, an aspect that remains poorly understood. We performed three experimental seasonal burn treatments (summer, fall, or spring) in tallgrass prairie and examined (1) the response of the flowering forb community in terms of density and diversity, and (2) how individual milkweed plants ( Asclepias spp.) invested in nectar to recruit pollinators. We found that burn timing did not affect flowering forb density but did impact flowering forb diversity: It was lowest following spring burns, whereas summer‐ and fall‐burned plots were more diverse. Nectar sucrose concentrations in milkweeds, however, were not affected by the timing of burns but rather seemed robust in their investment to recruit pollinators. Therefore, while individual plant investment strategies may be more sensitive to other factors, the timing of prescribed burns seems important in promoting flowering forb diversity, which could have important downstream consequences on the diversity of pollinators and other animal communities.