Skip to Main Content
Have changing forests conditions contributed to pollinator decline in the southeastern United States?Author(s): James L. Hanula; Scott Horn; Joseph J. O'Brien
Source: Forest Ecology and Management 348 (2015) 142–152
Publication Series: Scientific Journal (JRNL)
Station: Southern Research Station
View PDF (1.8 MB)
DescriptionTwo conservation goals of the early 20th century, extensive reforestation and reduced wildfire through fire exclusion, may have contributed to declining pollinator abundance as forests became denser and shrub covered. To examine how forest structure affects bees we selected 5 stands in each of 7 forest types including: cleared forest; dense young pines; thinned young pines; mature open pine with extensive shrub/sapling cover; mature open pine with extensive herbaceous plant cover and little shrub cover; mature upland hardwood forest; and mature riparian hardwood forest. We sampled bees during the 2008 growing season using pan traps and measured overstory tree density, understory herbaceous plant and shrub diversity and cover, light penetration, and leaf area index. Numbers of bees and numbers of species per plot were highest in cleared forest and in mature pine stands with an herbaceous plant understory. Estimates of asymptotic species richness were highest in mature riparian hardwood forests, cleared forests and open pine forests with an herbaceous plant understory. Bee communities in the cleared forests and in the mature pine with an herbaceous plant understory were grouped together in ordination space which was consistent with perMANOVA results. The best predictor variable for bee species density was total tree basal area which was negatively correlated (r2 = 0.58), while the best model for predicting bee abundance (r2 = 0.62) included canopy openness, plant species density (both positively correlated) and shrub cover (negatively correlated). Our results combined with many others show that thinning forests combined with shrub control provides good bee habitat, is compatible with habitat restoration and management for other species, and the resulting forests will be healthier and less susceptible to old (e.g., southern pine beetle, Dendroctonus frontalis) and new (European woodwasp, Sirex noctilio) threats.
- You may send email to email@example.com to request a hard copy of this publication.
- (Please specify exactly which publication you are requesting and your mailing address.)
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationHanula, James L.; Horn, Scott; O'Brien, Joseph J. 2015. Have changing forests conditions contributed to pollinator decline in the southeastern United States?. Forest Ecology and Management 348 (2015) 142–152 11 p.
KeywordsApoidea, Pollinator decline, Forest cover, Native bees, Solitary bees, Forest health
- Pollinating bees crucial to farming wildflower seed for U.S. habitat restoration
- Meeting wild bees' needs on Western US rangelands
- The importance of bees in natural and agricultural ecosystems
XML: View XML