The Impact of Prescribed Burning on Native Bee Communities (Hymenoptera: Apoidea: Anthophila) in Longleaf Pine Savannas in the North Carolina Sandhills.

Prescribed burning is a common silvicultural practice used in the management of longleaf pine (Pinus palustris Mill., Pinales: Pinaceae) savannas to reduce hardwood encroachment and ground cover and to maintain biodiversity. We investigated the response of the native bee community (Hymenoptera: Apoidea: Anthophila) in the Sandhills of North Carolina to prescribed burning on a 3-yr rotation over two consecutive years (2012 and 2013). We deployed bee bowl traps in sites that had been burned the year of sampling, 1 yr before, 2 yr before, and in unburned controls. In total, 2,276 bees of 109 species were captured. Bee abundance declined with time since fire, with 2.3 times more bees captured in the most recently burned sites than in unburned controls. Bee diversity also declined with time since fire, with 2.1 times more species captured in the most recently burned sites than in controls. Bee community composition also responded to fire; we present evidence that this response was mediated in part by the effect of fire on the amount of bare ground and canopy cover. Bees nesting aboveground were unaffected by fire, contrary to our expectation that fire would destroy the wood and stems in which these species nest. Our results indicate that prescribed burning is a silvicultural practice consistent with pollinator conservation in longleaf pine ecosystems of the North Carolina sandhills.