Recent post-wildfire salvage logging benefits local and landscape floral and bee communities

Understanding the implications of shifts in disturbance regimes for plants and pollinators is essential for successful land management. Wildfires are essential natural disturbances that are important drivers of forest biodiversity, and there is often pressure to respond to wildfire with management like post-wildfire logging (i.e., removal of dead trees for economic value immediately following wildfire). We investigated how local floral and bee density, species richness, and community composition and dispersion were influenced by post-wildfire logging, and how these effects differed between an older (24 years-since-fire) and a more recent (8 years-since-fire) wildfire in the Gallatin National Forest, Montana USA. We also tested how these local patterns scaled up to influence landscape patterns in floral and bee diversity. After recent wildfire, local floral and bee density and species richness were higher in logged than in unlogged sites, and these effects were variable over the course of the growing season. There were no differences in community dispersion except that of bees in logged areas of the recent wildfire, which were less heterogeneous compared to unlogged areas. Despite this reduction in bee community heterogeneity, overall bee diversity was highest across logged areas of the recent fire. While the positive effects of post-wildfire logging on local density and richness did not persist in the older fire, compositional differences in flowers and bees between logged and unlogged areas were observed in both the recent and older wildfire. Together, these results suggest that the local benefits of post-wildfire logging for floral and bee richness are evident within a decade of these disturbances, but have diminished within a quarter century of fire. Nevertheless, compositional effects persist, resulting in higher overall landscape floral and bee diversity when both logged and unlogged areas of each wildfire were present. This study provides evidence for near-term benefits of post-wildfire logging for local and landscape floral and bee communities. Post-wildfire logging may be considered as a forest management option when balanced with the maintenance of unlogged areas to encourage biodiversity conservation at the landscape scale.