Influence of Nesting Characteristics on Health of Wild Bee Communities

2020 ◽  
Vol 65 (1) ◽  
pp. 39-56 ◽  
Author(s):  
Alexandra Harmon-Threatt

Nest site availability and quality are important for maintaining robust populations and communities of wild bees. However, for most species, nesting traits and nest site conditions are poorly known, limiting both our understanding of basic ecology for bee species and conservation efforts. Additionally, many of the threats commonly associated with reducing bee populations have effects that can extend into nests but are largely unstudied. In general, threats such as habitat disturbances and climate change likely affect nest site availability and nest site conditions, which in turn affect nest initiation, growth, development, and overwintering success of bees. To facilitate a better understanding of how these and other threats may affect nesting bees, in this review, I quantify key nesting traits and environmental conditions and then consider how these traits may intersect with observed and anticipated changes in nesting conditions experienced by wild bees. These data suggest that the effects of common threats to bees through nesting may strongly influence their survival and persistence but are vastly understudied. Increasing research into nesting biology and incorporating nesting information into conservation efforts may help improve conservation of this declining but critical group.

2020 ◽  
Vol 49 (2) ◽  
pp. 502-515 ◽  
Author(s):  
Brianne Du Clos ◽  
Francis A Drummond ◽  
Cynthia S Loftin

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.


PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3051 ◽  
Author(s):  
Étienne Normandin ◽  
Nicolas J. Vereecken ◽  
Christopher M. Buddle ◽  
Valérie Fournier

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.


2015 ◽  
Vol 282 (1809) ◽  
pp. 20150299 ◽  
Author(s):  
Mia G. Park ◽  
E. J. Blitzer ◽  
Jason Gibbs ◽  
John E. Losey ◽  
Bryan N. Danforth

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.


Author(s):  
Rachel A. Nalepa ◽  
Graham Epstein ◽  
Jeremy Pittman ◽  
Sheila R. Colla

Abstract Pollination services are critical for food production. Although domesticated honey bees are important pollinators in agriculture, there is growing interest in supporting naturally occurring wild bees. Diversifying pollination management strategies by encouraging healthy wild bee communities may be especially useful for growers of insect-pollinated crops, such as apples. Although research has identified several land management practices that can enhance local pollinator communities on farms, there are few studies on the factors that influence growers to adopt pollinator-supporting actions on their land. Here, we surveyed 75 Canadian apple growers and used regression models to explore the influence of farm characteristics and perceptions about bees on the likelihood of adopting 15 unique pollinator-supporting practices. We also provide a descriptive analysis of growers' pollination management practices and self-assessed resourcefulness on the ability to improve habitat for wild pollinators on the farm. We found that an increase in three variables: awareness of wild bees, perception of the severity of threats facing wild populations, and the perception of the benefits provided by wild bees is associated with more pollinator-supporting practices on the farm. Overall, growers were less likely to adopt pollinator-friendly practices as the fraction of rented land increased and as the perceived costs of implementing these practices rose. We found ‘low-hanging fruit’ (i.e., pollinator-supporting practices that could be easily and inexpensively implemented) were adopted by less than one-third of growers and that the majority of those surveyed had little to no knowledge on what actions to take if they wanted to improve their farms for wild bees or where to go for that knowledge. Our results suggest that policies and programs that focus on raising grower awareness of wild bees, increasing grower perception of their benefits, and reducing the perceived costs of implementing pollinator-supporting practices may positively affect their uptake. A deeper understanding of grower perceptions will provide essential insight into how growers may contribute to wild pollinator conservation while potentially increasing agricultural production and reducing vulnerability borne of heavy reliance on managed pollinators.


2021 ◽  
Vol 29 ◽  
pp. 204-230
Author(s):  
Julie Anne Weissmann ◽  
Iris Rebecca Magdalena Walldorf ◽  
Hanno Schaefer

While urban beekeeping is on the rise, data on the role of wild bee communities as crop pollinators in cities is still scarce. We analysed wild bee visitation rates on apple, plum, cherry, pear, blackberry, raspberry, and strawberry in a Bavarian city with a very high honeybee density of c. 19 hives/km2. During 137.5 hours of observation time, we observed 52 wild bee species on the studied crop plants. During more than 50 h of observation time on fruit trees in flower, we found that wild bees provided 41% of the total bee visits, honeybees the remaining 59%. Honeybee hive density had a significantly negative effect on wild bee abundance. Bumblebees appeared more tolerant to poor weather conditions than all other bee groups. Wild bee species richness on apple flowers was not significantly impacted by flower diversity in the surroundings of the trees. Together, our results suggest that species-rich wild bee communities in urban areas are important for pollination success in common fruit crops, especially under unstable spring weather conditions. Bee-friendly management of urban spaces should be prioritised to support wild bee communities as well as the increasing number of honeybees in cities.


2021 ◽  
Vol 9 ◽  
Author(s):  
Imre Demeter ◽  
Adalbert Balog ◽  
Miklós Sárospataki

During the study, the honeybee effects on wild bees were tested and hypothesized that smaller distances from beehives will increase competitions between honeybees and wild bees, while greater distances will have a deleterious effect on competition. The impact on species richness and diversity was tested with distances from beehives, considering that this may differ when large and small wild bee species are considered separately. Altogether 158 species and 13,164 individuals were collected, from which 72% (9,542 individuals) were Apis mellifera. High variation in abundances was detected from one year to another, and the species turnover by sites was 67% in site A, 66% in site V, and 63% in site F. This last one was the site with the previous contact with honeybees. Considering distances from beehives, significant decreases in small bee species diversity were detected from one year to another at each distance except site F, 250 m from hives. The changes in species diversity and community structure of small bee species are detected from one year to another.


2019 ◽  
pp. 1-34 ◽  
Author(s):  
Tracy A. Zarrillo ◽  
Kimberly A. Stoner

 With growing evidence of changes in local abundance, geographical range, and species diversity of wild bees, it is imperative to document wild bee communities in representative habitats throughout North America. The Connecticut shoreline has historically been subject to many natural and anthropogenic disturbances, and there is a lack of baseline data regarding bee biodiversity in Connecticut’s maritime habitats. In this study, we characterize the wild bee fauna of a discrete maritime habitat in Connecticut, USA, and examine salt-marsh, beach dune, and coastal scrub bee communities adjacent to Long Island Sound. Patterns found are discussed in relation to recent coastal surveys in New England. Biweekly surveys were conducted at Grass Island (Guilford, CT) over a two-year period (2011-2012) using pan traps and effort-based (timed) net collecting from flowers. A total of 3928 individual bees were collected, representing five families, 18 genera and at least 80 species. Floral records for 374 individuals resulted in associations of 35 bee species with 19 species of flowers. Seventy percent of the bees captured in the net survey were visiting alien plants, with the exotic Rosa rugosa Thunb. having the highest level of bee diversity and relative abundance. The total number of bee species collected in this survey represents approximately 23% of the known Connecticut fauna, including four specialists associated with coastal and wetland habitats. The abundance and diversity of bees visiting alien plants on Grass Island, as well as the occurrence of these sand specialists, may prove to be of conservation concern as the Connecticut shoreline continues to be altered.  


Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1413
Author(s):  
Sara L. Bushmann ◽  
Francis A. Drummond

Maine is the largest producer of wild blueberry (Vaccinium angustifolium Aiton) in the United States. Pollination comes from combinations of honey bees (Apis mellifera (L.)), commercial bumble bees (Bombus impatiens Cresson), and wild bees. This study addresses (1) previous research addressing wild-blueberry pollination, (2) effects of wild-bee and honey-bee activity densities on fruit set, yield, and crop value, (3) the economic value of wild-bee communities, and (4) economic consequences of pollinator loss. Bee communities were sampled in 40 fields over three years (2010–2012) and bee activity densities were estimated for bumble bees, honey bees, and other wild bees. These data were applied to an economic model to estimate the value of bee taxa. Bumble bees and honey bees predicted fruit set and reduced its spatial heterogeneity. Other wild bees were not significant predictors of fruit set. Yield was predicted by fruit set and field size, but not pest management tactics. Our analysis showed that disruption in supply of honey bees would result in nearly a 30% decrease in crop yield, buffered in part by wild bees that provide “background” levels of pollination. Honey-bee stocking density and, thus, the activity density of honey bees was greater in larger fields, but not for wild bees. Therefore, a decrease in crop yield would be greater than 30% for large fields due to the proportionally greater investment in honey bees in large fields and a relatively lower contribution by wild bees.


Insects ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 812
Author(s):  
Justine Rivers-Moore ◽  
Emilie Andrieu ◽  
Aude Vialatte ◽  
Annie Ouin

Loss of semi-natural habitats (SNH) in agricultural landscapes affects wild bees, often negatively. However, how bee communities respond varies and is still unclear. To date, few studies have used precise descriptors to understand these effects. Our aim was to understand the respective and complementary influences of different wooded and herbaceous habitats on wild bee communities. We selected thirty 500-m radius landscapes on a gradient of a percentage of wooded SNH in south-western France. At each landscape, we sampled wild bees in spring 2016 and plants in spring 2015 and 2016 at the forest edge, in a hedgerow, and in a permanent grassland. Pollen carried by the most abundant bee species was collected and identified. Using beta diversity indices, we showed that wild bee community composition differs between the three SNH types, and especially between herbaceous and wooded SNH. Based on Jacobs’ selection index, we showed that pollen of some plant species recorded in wooded SNH are preferentially selected by wild bees. Studying the impact of the loss of each SNH type on the global bee-pollen interaction network, we found that wooded SNH contributed to its resilience, enabling specific plant–bee interactions. Overall, our results underline the non-negligible contribution of wooded SNH to the diversity of wild bees in agricultural landscapes, and thus the importance of maintaining different types of SNH.


2021 ◽  
Vol 67 (2) ◽  
pp. 161-175
Author(s):  
Imre Demeter ◽  
Adalbert Balog ◽  
Zsolt Józan ◽  
Miklós Sárospataki

In the temperate climate wild bees are the most important pollinator organisms. Pollination is essential for the communities of semi-natural habitats since this ecosystem service directly affects plant reproduction. The diversity of wild bees living in such areas is remarkably high, but they are susceptible to various anthropogenic influences.In our study, the composition and structure of wild bee communities were examined in Romania (Transylvania) at three semi-natural areas near Filia, Merești and Vârghiș. The surveyed areas were used as extensive meadows under relatively low but slightly different anthropogenic influence levels. We collected bees in these areas at several places (9 sampling points/area) by individual netting four times during the season. In the studied areas, 129 bee species were found, which makes up about 18% of the approximately 726 wild bee species registered in Romania. In addition to the high number of species, we also observed high diversity values. Our results showed that, even at our sampling site closest to the human settlements, the extensive use of the surveyed areas as meadows allows the development of diverse, species-rich bee communities.


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