Changes in the Summer Wild Bee Community Following a Bark Beetle Outbreak in a Douglas-fir Forest

2020 ◽  
Vol 49 (6) ◽  
pp. 1437-1448 ◽  
Author(s):  
Gabriel G Foote ◽  
Nathaniel E Foote ◽  
Justin B Runyon ◽  
Darrell W Ross ◽  
Christopher J Fettig
Keyword(s):  
United States ◽  
Species Richness ◽  
Bark Beetle ◽  
Tree Mortality ◽  
Canopy Cover ◽  
Douglas Fir ◽  
Wild Bee ◽  
Bee Community ◽  
Bee Communities ◽  
Bee Abundance

Abstract The status of wild bees has received increased interest following recent estimates of large-scale declines in their abundances across the United States. However, basic information is limited regarding the factors affecting wild bee communities in temperate coniferous forest ecosystems. To assess the early responses of bees to bark beetle disturbance, we sampled the bee community of a Douglas-fir, Pseudotsuga menziesii (Mirb.), forest in western Idaho, United States during a Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins (Coleoptera: Curculionidae), outbreak beginning in summer 2016. We resampled the area in summer 2018 following reductions in forest canopy cover resulting from mortality of dominant and codominant Douglas-fir. Overall, results from rarefaction analyses indicated significant increases in bee diversity (Shannon’s H) in 2018 compared to 2016. Results from ANOVA also showed significant increases in bee abundance and diversity in 2018 compared to 2016. Poisson regression analyses revealed percent tree mortality from Douglas-fir beetle was positively correlated with increases in total bee abundance and species richness, where community response variables displayed a cubic trend with percent tree mortality. Percent reduction in canopy cover from 2016 to 2018 was also correlated with bee species richness and diversity. These findings suggest that wild bee communities may benefit from changes in forest structure following bark beetle outbreaks.

scholarly journals Noncrop Habitat Use by Wild Bees (Hymenoptera: Apoidea) in a Mixed-Use Agricultural Landscape

2020 ◽  
Vol 49 (2) ◽  
pp. 502-515 ◽  
Author(s):  
Brianne Du Clos ◽  
Francis A Drummond ◽  
Cynthia S Loftin
Keyword(s):  
United States ◽  
Floral Resources ◽  
Northeastern United States ◽  
Wild Bees ◽  
Wild Bee ◽  
Lowbush Blueberry ◽  
Mixed Use ◽  
Abundance And Diversity ◽  
Bee Communities ◽  
Bee Abundance

Abstract Homogeneous, agriculturally intense landscapes have abundant records of pollinator community research, though similar studies in the forest-dominated, heterogeneous mixed-use landscape that dominates the northeastern United States are sparse. Trends of landscape effects on wild bees are consistent across homogeneous agricultural landscapes, whereas reported studies in the northeastern United States have not found this consistency. Additionally, the role of noncrop habitat in mixed-use landscapes is understudied. We assessed wild bee communities in the mixed-use lowbush blueberry (Vaccinium angustifolium Ait.) production landscape of Maine, United States at 56 sites in eight land cover types across two regional landscapes and analyzed effects of floral resources, landscape pattern, and spatial scale on bee abundance and species richness. Within survey sites, cover types with abundant floral resources, including lowbush blueberry fields and urban areas, promoted wild bee abundance and diversity. Cover types with few floral resources such as coniferous and deciduous/mixed forest reduced bee abundance and species richness. In the surrounding landscape, lowbush blueberry promoted bee abundance and diversity, while emergent wetland and forested land cover strongly decreased these measures. Our analysis of landscape configuration revealed that patch mixing can promote wild bee abundance and diversity; however, this was influenced by strong variation across our study landscape. More surveys at intra-regional scales may lead to better understanding of the influence of mixed-use landscapes on bee communities.

scholarly journals Honey bee hives decrease wild bee abundance, species richness, and fruit count on farms regardless of wildflower strips

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
G. M. Angelella ◽  
C. T. McCullough ◽  
M. E. O’Rourke
Keyword(s):  
Species Richness ◽  
Honey Bee ◽  
Crop Pollination ◽  
Pollination Services ◽  
Wild Bee ◽  
Wildflower Strips ◽  
Negative Impacts ◽  
Bee Communities ◽  
Winter Squash ◽  
Bee Abundance

AbstractPollinator refuges such as wildflower strips are planted on farms with the goals of mitigating wild pollinator declines and promoting crop pollination services. It is unclear, however, whether or how these goals are impacted by managed honey bee (Apis mellifera L.) hives on farms. We examined how wildflower strips and honey bee hives and/or their interaction influence wild bee communities and the fruit count of two pollinator-dependent crops across 21 farms in the Mid-Atlantic U.S. Although wild bee species richness increased with bloom density within wildflower strips, populations did not differ significantly between farms with and without them whereas fruit counts in both crops increased on farms with wildflower strips during one of 2 years. By contrast, wild bee abundance decreased by 48%, species richness by 20%, and strawberry fruit count by 18% across all farm with honey bee hives regardless of wildflower strip presence, and winter squash fruit count was consistently lower on farms with wildflower strips with hives as well. This work demonstrates that honey bee hives could detrimentally affect fruit count and wild bee populations on farms, and that benefits conferred by wildflower strips might not offset these negative impacts. Keeping honey bee hives on farms with wildflower strips could reduce conservation and pollination services.

Effect of meadow regeneration on bee (Hymenoptera: Apoidea) abundance and diversity in southern Ontario, Canada

2013 ◽  
Vol 145 (6) ◽  
pp. 655-667 ◽  
Author(s):  
Amy C. Rutgers-Kelly ◽  
Miriam H. Richards
Keyword(s):  
Species Richness ◽  
First Year ◽  
Southern Ontario ◽  
Landfill Sites ◽  
Bee Diversity ◽  
Bee Community ◽  
Abundance And Diversity ◽  
And Control ◽  
Pan Traps ◽  
Bee Abundance

AbstractTo investigate how bee (Hymenoptera: Apoidea) communities repopulate habitat following severe disturbances, we compared assemblages in new, regenerating landfill sites planted in 2003, recent landfill sites planted in 2000, and control meadows relatively undisturbed for >40 years. All sites were identically sampled using pan traps and sweep netting, from early May to late September 2003, equalising collection effort among sites. In addition, we carried out five-minute aerial net samplings wherever sites contained large patches of wildflowers. We predicted that abundance and diversity of bees would be highest in recent sites and lowest in new sites. This prediction was partially supported: bees were most abundant in recent sites followed by control, then new sites, but species richness was highest (82 species) in recent sites, followed by new sites (67 species), then control (66 species). A randomisation analysis showed that there were more species than expected in new sites and fewer than expected in control sites. Differences in blossom availability likely explain differences in bee abundance and diversity among habitat regeneration levels. Overall, our results suggest that the bee community recolonised newly available sites immediately in the first year and that bee diversity and abundance increased for at least three years, subsequently declining between three and 40 years.

scholarly journals Taxonomic and functional trait diversity of wild bees in different urban settings

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3051 ◽  
Author(s):  
Étienne Normandin ◽  
Nicolas J. Vereecken ◽  
Christopher M. Buddle ◽  
Valérie Fournier
Keyword(s):  
Community Gardens ◽  
Functional Trait ◽  
Quebec City ◽  
Wild Bees ◽  
Structure And Dynamics ◽  
Wild Bee ◽  
Trait Diversity ◽  
Bee Community ◽  
Bee Communities ◽  
Functional Trait Diversity

Urbanization is one of the major anthropogenic processes contributing to local habitat loss and extirpation of numerous species, including wild bees, the most widespread pollinators. Little is known about the mechanisms through which urbanization impacts wild bee communities, or the types of urban green spaces that best promote their conservation in cities. The main objective of this study was to describe and compare wild bee community diversity, structure, and dynamics in two Canadian cities, Montreal and Quebec City. A second objective was to compare functional trait diversity among three habitat types (cemeteries, community gardens and urban parks) within each city. Bees were collected using pan traps and netting on the same 46 sites, multiple times, over the active season in 2012 and 2013. A total of 32,237 specimens were identified, representing 200 species and 6 families, including two new continental records,Hylaeus communisNylander (1852) andAnthidium florentinum(Fabricius, 1775). Despite high community evenness, we found significant abundance of diverse species, including exotic ones. Spatio-temporal analysis showed higher stability in the most urbanized city (Montreal) but low nestedness of species assemblages among the three urban habitats in both cities. Our study demonstrates that cities are home to diverse communities of wild bees, but in turn affect bee community structure and dynamics. We also found that community gardens harbour high levels of functional trait diversity. Urban agriculture therefore contributes substantially to the provision of functionally diverse bee communities and possibly to urban pollination services.

Native wildflower plantings support wild bee abundance and diversity in agricultural landscapes across the United States

2015 ◽  
Vol 25 (8) ◽  
pp. 2119-2131 ◽  
Author(s):  
Neal M. Williams ◽  
Kimiora L. Ward ◽  
Nathaniel Pope ◽  
Rufus Isaacs ◽  
Julianna Wilson ◽  
...  
Keyword(s):  
United States ◽  
The United States ◽  
Agricultural Landscapes ◽  
Wild Bee ◽  
Abundance And Diversity ◽  
Bee Abundance

scholarly journals Negative effects of pesticides on wild bee communities can be buffered by landscape context

2015 ◽  
Vol 282 (1809) ◽  
pp. 20150299 ◽  
Author(s):  
Mia G. Park ◽  
E. J. Blitzer ◽  
Jason Gibbs ◽  
John E. Losey ◽  
Bryan N. Danforth
Keyword(s):  
Pesticide Exposure ◽  
Natural Habitat ◽  
Landscape Context ◽  
Pesticide Use ◽  
Natural Areas ◽  
Wild Bees ◽  
Pollination Services ◽  
Wild Bee ◽  
Bee Community ◽  
Bee Communities

Wild bee communities provide underappreciated but critical agricultural pollination services. Given predicted global shortages in pollination services, managing agroecosystems to support thriving wild bee communities is, therefore, central to ensuring sustainable food production. Benefits of natural (including semi-natural) habitat for wild bee abundance and diversity on farms are well documented. By contrast, few studies have examined toxicity of pesticides on wild bees, let alone effects of farm-level pesticide exposure on entire bee communities. Whether beneficial natural areas could mediate effects of harmful pesticides on wild bees is also unknown. Here, we assess the effect of conventional pesticide use on the wild bee community visiting apple ( Malus domestica ) within a gradient of percentage natural area in the landscape. Wild bee community abundance and species richness decreased linearly with increasing pesticide use in orchards one year after application; however, pesticide effects on wild bees were buffered by increasing proportion of natural habitat in the surrounding landscape. A significant contribution of fungicides to observed pesticide effects suggests deleterious properties of a class of pesticides that was, until recently, considered benign to bees. Our results demonstrate extended benefits of natural areas for wild pollinators and highlight the importance of considering the landscape context when weighing up the costs of pest management on crop pollination services.

scholarly journals The impact of bark beetle infestations on monoterpene emissions and secondary organic aerosol formation in western North America

2013 ◽  
Vol 13 (6) ◽  
pp. 3149-3161 ◽  
Author(s):  
A. R. Berg ◽  
C. L. Heald ◽  
K. E. Huff Hartz ◽  
A. G. Hallar ◽  
A. J. H. Meddens ◽  
...  
Keyword(s):  
United States ◽  
British Columbia ◽  
North America ◽  
Bark Beetle ◽  
Tree Mortality ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Western United States ◽  
Western North America ◽  
The Impact

Abstract. Over the last decade, extensive beetle outbreaks in western North America have destroyed over 100 000 km2 of forest throughout British Columbia and the western United States. Beetle infestations impact monoterpene emissions through both decreased emissions as trees are killed (mortality effect) and increased emissions in trees under attack (attack effect). We use 14 yr of beetle-induced tree mortality data together with beetle-induced monoterpene emission data in the National Center for Atmospheric Research (NCAR) Community Earth System Model (CESM) to investigate the impact of beetle-induced tree mortality and attack on monoterpene emissions and secondary organic aerosol (SOA) formation in western North America. Regionally, beetle infestations may have a significant impact on monoterpene emissions and SOA concentrations, with up to a 4-fold increase in monoterpene emissions and up to a 40% increase in SOA concentrations in some years (in a scenario where the attack effect is based on observed lodgepole pine response). Responses to beetle attack depend on the extent of previous mortality and the number of trees under attack in a given year, which can vary greatly over space and time. Simulated enhancements peak in 2004 (British Columbia) and 2008 (US). Responses to beetle attack are shown to be substantially larger (up to a 3-fold localized increase in summertime SOA concentrations) in a scenario based on bark-beetle attack in spruce trees. Placed in the context of observations from the IMPROVE network, the changes in SOA concentrations due to beetle attack are in most cases small compared to the large annual and interannual variability in total organic aerosol which is driven by wildfire activity in western North America. This indicates that most beetle-induced SOA changes are not likely detectable in current observation networks; however, these changes may impede efforts to achieve natural visibility conditions in the national parks and wilderness areas of the western United States.

scholarly journals Modeling the status, trends, and impacts of wild bee abundance in the United States

2015 ◽  
Vol 113 (1) ◽  
pp. 140-145 ◽  
Author(s):  
Insu Koh ◽  
Eric V. Lonsdorf ◽  
Neal M. Williams ◽  
Claire Brittain ◽  
Rufus Isaacs ◽  
...  
Keyword(s):  
United States ◽  
The United States ◽  
Habitat Model ◽  
Wild Plant ◽  
Wild Bees ◽  
Natural Habitats ◽  
Row Crops ◽  
Wild Bee ◽  
The Status ◽  
Bee Abundance

Wild bees are highly valuable pollinators. Along with managed honey bees, they provide a critical ecosystem service by ensuring stable pollination to agriculture and wild plant communities. Increasing concern about the welfare of both wild and managed pollinators, however, has prompted recent calls for national evaluation and action. Here, for the first time to our knowledge, we assess the status and trends of wild bees and their potential impacts on pollination services across the coterminous United States. We use a spatial habitat model, national land-cover data, and carefully quantified expert knowledge to estimate wild bee abundance and associated uncertainty. Between 2008 and 2013, modeled bee abundance declined across 23% of US land area. This decline was generally associated with conversion of natural habitats to row crops. We identify 139 counties where low bee abundances correspond to large areas of pollinator-dependent crops. These areas of mismatch between supply (wild bee abundance) and demand (cultivated area) for pollination comprise 39% of the pollinator-dependent crop area in the United States. Further, we find that the crops most highly dependent on pollinators tend to experience more severe mismatches between declining supply and increasing demand. These trends, should they continue, may increase costs for US farmers and may even destabilize crop production over time. National assessments such as this can help focus both scientific and political efforts to understand and sustain wild bees. As new information becomes available, repeated assessments can update findings, revise priorities, and track progress toward sustainable management of our nation’s pollinators.

scholarly journals Changes in Transpiration and Leaf Water Potential in Douglas-Fir Trees following Douglas-Fir Beetle Attack and Mechanical Girdling

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1722
Author(s):  
Javier E. Mercado ◽  
Robert T. Walker ◽  
Scott Franklin ◽  
Shannon L. Kay ◽  
Susana Karen Gomez ◽  
...  
Keyword(s):  
Water Potential ◽  
Bark Beetle ◽  
Leaf Water Potential ◽  
Bark Beetles ◽  
Tree Mortality ◽  
Douglas Fir ◽  
Leaf Water ◽  
Lodgepole Pines ◽  
And Control ◽  
Phloem Feeding

Bark beetles and their associated fungi kill trees readily, but we often ignore which organism is the leading cause of tree mortality. While phloem feeding beetles inhibit photosynthate transport, their associated fungi block the tracheids disrupting transpiration. Within the family Pinaceae, knowledge of tree physiological decline following bark beetle and associated fungi colonization is limited to the genus Pinus. Here we investigate the physiological response of Pseudotsuga (P. menziesii) to bark beetles or its fungi. We hypothesized that fungi block water transport in Douglas-fir causing faster mortality than by bark beetle activity alone. We successfully lured Douglas-fir beetle to attack a subset of trees in our experimental area using pheromones and compared Beetle-Killed trees with mechanically Girdled, and Control trees. During spring snowmelt, nine months after treatments were applied, Control, Girdled, and five trees that Survived beetle attack had higher transpiration rates and less negative pre-dawn water potential than five Beetle-Killed trees. Declines in transpiration and leaf water potential in our Beetle-Killed trees occurred much earlier than those in studies of beetle-attacked lodgepole pines, suggesting stronger defensive traits in Douglas-fir. Our data suggest that, as in pines, bark beetle-associated fungi are the leading cause of mortality in Douglas-fir beetle-attacked trees.

Sign in / Sign up

Export Citation Format

Share Document