Fire heterogeneity promotes pollinator diversity in southeastern U.S. pine forests

Michael D. Ulyshen, USDA Forest Service, Athens, GA, J. Kevin Hiers and Scott Pokswinski, Fire Research, Tall Timbers Research Station, Tallahassee, FL, Conor Fair, university of georgia

Background/Question/Methods
Fire is a key determinant of vegetation structure and composition in ecosystems throughout the world. The ‘pyrodiversity hypothesis’, predicting that biodiversity will increase as fire diversity increases, remains largely untested for pollinators, a group of high conservation concern. In this study, we tested the relationship between pollinator diversity and pyrodiversity within a 250 m radius based on a decade of burn history in Florida. Bees and butterflies were sampled for one season using colored pan traps and pyrodiversity was assessed by quantifying fire richness (i.e., the number of unique fire histories) and fire Shannon’s diversity surrounding each of our sampling locations.
Results/Conclusions
We identified a total of 113 unique fire histories, with a range of 4-26, within 250 m of our sampling locations. Both bees and butterflies responded positively to fire richness and diversity. In addition, our results indicate high fire frequency may be detrimental to butterflies overall and to some bee species. Highly idiosyncratic responses were detected among individual bee species, indicating that there can be no “one size fits all” management strategy for bees. Our findings reveal the important role fire history plays in shaping pollinator communities and show that efforts to increase fire heterogeneity can benefit this fauna in fire-managed landscapes.