University of California Sacramento, California, United States
Flower-visiting insects provide essential pollination services to herbaceous plant communities in temperate coniferous forests, thereby helping to maintain food webs and support the overall functional diversity of these systems. To guide conservation efforts for forest-associated populations in western North America, ecologists have investigated the effects of both natural (drought, insect outbreaks, wildfire) and anthropogenic (forestry operations) disturbances on local insect pollinator abundance and diversity. However, studies comparing their community responses to the different types of forest disturbance (i.e., abiotic versus biotic or anthropogenic) that have co-occurred within an individual forest landscape are few. To address this knowledge gap, we sampled the insect pollinator community during the summer of 2020 in undisturbed forest stands, combined with neighboring stands that underwent recent (post-2015) disturbance (drought, tree harvest, wildfire) located in mid-montane forest landscapes of the Californian central Sierra Nevada. In short, disturbed stands had a higher diversity of pollinators compared to neighboring, undisturbed stands. However, the magnitude of these differences varied by both disturbance type and severity. Overall, these results indicate that allowing for certain disturbances (e.g., moderate severity wildfires) that reduce shrub cover, expose bare ground surfaces and promote herbaceous plant growth on the forest floor may be optimal mechanisms for land managers to passively create beneficial habitat for insect pollinators in this ecoregion.
