Mass-flowering monoculture attracts bees, amplifying parasite prevalence

2021 ◽  
Vol 288 (1960) ◽  
Author(s):  
Hamutahl Cohen ◽  
Gordon P. Smith ◽  
Hillary Sardiñas ◽  
Jocelyn F. Zorn ◽  
Quinn S. McFrederick ◽  
...  
Keyword(s):  
Central Valley ◽  
Parasite Prevalence ◽  
Diet Breadth ◽  
Dispersal Ability ◽  
Mass Flowering ◽  
Resource Pulses ◽  
Floral Diversification ◽  
Wildlife Epidemiology ◽  
Bee Communities ◽  
Bee Abundance

As the global agricultural footprint expands, it is increasingly important to address the link between the resource pulses characteristic of monoculture farming and wildlife epidemiology. To understand how mass-flowering crops impact host communities and subsequently amplify or dilute parasitism, we surveyed wild and managed bees in a monoculture landscape with varying degrees of floral diversification. We screened 1509 bees from 16 genera in sunflower fields and in non-crop flowering habitat across 200 km 2 of the California Central Valley. We found that mass-flowering crops increase bee abundance. Wild bee abundance was subsequently associated with higher parasite presence, but only in sites with a low abundance of non-crop flowers. Bee traits related to higher dispersal ability (body size) and diet breadth (pollen lecty) were also positively related to parasite presence. Our results highlight the importance of non-crop flowering habitat for supporting bee communities. We suggest monoculture alone cannot support healthy bees.

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.

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 Livestock grazing is associated with seasonal reduction in pollinator biodiversity and functional dispersion but cheatgrass invasion is not: variation in bee assemblages in a multi-use shortgrass prairie

2020 ◽  
Author(s):  
Khum Bahadur Thapa-Magar ◽  
Thomas Seth Davis ◽  
Boris C. Kondratieff
Keyword(s):  
Growing Season ◽  
Cattle Grazing ◽  
Soil Disturbance ◽  
Livestock Grazing ◽  
Native Plant ◽  
Native Plant Species ◽  
Shortgrass Prairie ◽  
Functional Dispersion ◽  
Bee Communities ◽  
Bee Abundance

AbstractLivestock grazing and non-native plant species affect rangeland habitats globally. These factors may have important effects on ecosystem services including pollination, yet, interactions between pollinators, grazing, and invasive plants are poorly understood. To address this, we tested the hypothesis that cattle grazing and site colonization by cheatgrass (Bromus tectorum) impact bee foraging and nesting habitats, and the biodiversity of wild bee communities, in a shortgrass prairie system. Bee nesting habitats (litter and wood cover) were marginally improved in non-grazed sites, though foraging habitat (floral cover and richness) did not differ among grazed, non-grazed, or cheatgrass colonized sites. However, floral cover was a good predictor of bee abundance and functional dispersion. Mean bee abundance, richness, diversity and functional diversity were significantly lower in cattle-grazed habitats than in cheatgrass-colonized or non-grazed habitats. Differences in bee diversity among habitats were pronounced early in the growing season (May) but by late-season (August) these differences eroded. Fourth-corner analysis revealed that sites with high floral cover tended to support large, social, polylectic bees; sites with high grass cover tended to support oligolectic solitary bees. Both cattle-grazed and cheatgrass-colonized sites were associated with lower abundances of above-ground nesting bees but higher abundance of below-ground nesters. We conclude that cheatgrass-invaded sites are not associated with reduced bee biodiversity or abundance, but cattle grazing was negatively associated with bee abundances and altered species composition. Although floral cover is an important predictor of bee assemblages, this was not impacted by grazing and our suggests that cattle likely impact bee communities through effects other than those mediated by forbs, including soil disturbance or nest destruction. Efforts aimed at pollinator conservation in prairie habitats should focus on managing cattle impacts early in the growing season to benefit sensitive bee species.

scholarly journals The determinants of alpine butterfly richness and composition vary according to the ecological traits of species

2014 ◽  
Author(s):  
Vincent Sonnay ◽  
Loïc Pellissier ◽  
Jean-Nicolas Pradervand ◽  
Luigi Maiorano ◽  
Anne Dubuis ◽  
...  
Keyword(s):  
Species Richness ◽  
Essential Element ◽  
Diet Breadth ◽  
Habitat Diversity ◽  
Dispersal Ability ◽  
Global Changes ◽  
Butterfly Species ◽  
Environmental Predictors ◽  
Plant Richness ◽  
Main Determinants

Predicting spatial patterns of species diversity and composition using suitable environmental predictors is an essential element in conservation planning. Although species have distinct relationships to environmental conditions, some similarities may exist among species that share functional characteristics or traits. We investigated the relationship between species richness, composition and abiotic and biotic environment in different groups of butterflies that share ecological characteristics. We inventoried butterfly species richness in 192 sites and classified all inventoried species in three traits categories: the caterpillars diet breadth, the habitat requirements and the dispersal ability of the adults. We studied how environment, including influence butterfly species richness and composition within each trait category. Across four modelling approaches, the relative influence of environmental variables on butterfly species richness differed for specialists and generalists. Climatic variables were the main determinants of butterfly species richness and composition for generalists, whereas habitat diversity, and plant richness were also important for specialists. Prediction accuracy was lower for specialists than for generalists. Although climate variables represent the strongest drivers affecting butterfly species richness and composition for generalists, plant richness and habitat diversity are at least as important for specialist butterfly species. As specialist butterflies are among those species particularly threatened by global changes, devising accurate predictors to model specialist species richness is extremely important. However, our results indicate that this task will be challenging because more complex predictors are required.

scholarly journals Evaluating Native Bee Communities and Nutrition in Managed Grasslands

2020 ◽  
Vol 49 (3) ◽  
pp. 717-725
Author(s):  
D S Stein ◽  
D M Debinski ◽  
J M Pleasants ◽  
A L Toth
Keyword(s):  
Community Composition ◽  
Tallgrass Prairie ◽  
Native Species ◽  
Management Strategies ◽  
Health Indicators ◽  
Flowering Plant ◽  
Floral Resources ◽  
Pollinator Community ◽  
Bee Communities ◽  
Bee Abundance

Abstract Native pollinators are important for providing vital services in agroecosystems; however, their numbers are declining globally. Bees are the most efficient and diverse members of the pollinator community; therefore, it is imperative that management strategies be implemented that positively affect bee community composition and health. Here, we test responses of the bee and flowering plant communities to land management treatments in the context of grasslands in the upper Midwestern United States, a critical area with respect to bee declines. Twelve sites were selected to examine floral resources and wild bee communities based on three different types of grasslands: tallgrass prairie remnants, ungrazed restorations, and grazed restorations. Total bee abundance was significantly higher in ungrazed restorations than remnants, but there were no significant differences among grasslands in community composition or Shannon diversity. Across the three grassland types we also examined mass and lipid stores as nutritional health indicators in three sweat bees (Halictidae), Augochlora pura, Agapostemon virescens, and Halictus ligatus. Although there were no differences in lipid content, total average bee mass was significantly higher in Ag. virescens collected from ungrazed restorations as compared to remnants. Floral abundance of native and non-native species combined was significantly higher in grazed restorations compared to remnants and ungrazed restorations. However, ungrazed restorations had higher abundance and richness of native flowering ramets. These data suggest that bee abundance and nutrition are driven by high abundance of native flowering plant species, rather than total flowering plants.

scholarly journals Species traits predict extinction risk across the Tree of Life

2020 ◽  
Author(s):  
Filipe Chichorro ◽  
Fernando Urbano ◽  
Dinarte Teixeira ◽  
Henry Väre ◽  
Tiago Pinto ◽  
...  
Keyword(s):  
Extinction Risk ◽  
Species Traits ◽  
Diet Breadth ◽  
Global Scale ◽  
Tree Of Life ◽  
Offspring Size ◽  
Future Research ◽  
Dispersal Ability ◽  
Human Footprint ◽  
Habitat Breadth

SummaryBiodiversity is eroding at unprecedented rates due to human activity1. Species’ trajectories towards extinction are shaped by multiple factors, including life-history traits2 as well as human pressures3. Previous studies linking these factors to extinction risk have been narrow in their taxonomic and geographic scope4, thus limiting the ability for identifying global predictors. We studied the relation between 12 traits and the extinction risk of almost 900 species representing 15 groups across the tree of life (vertebrates, invertebrates and plants) at a global scale. We show that threatened species share narrow habitat breadth, poor dispersal ability, low fecundity, small altitudinal range, and are affected by a large human footprint. Other traits either show contrasting responses among groups (body size, offspring size, and change in human footprint), or relations were found for only a limited number of taxa (generation length, diet breadth, microhabitat). Our study suggests that in the absence of data on the precise distribution and population trends of species, traits can be used as predictors of extinction risk and thus help guide future research, monitoring and conservation efforts.

scholarly journals Does urbanization favour exotic bee species? Implications for the conservation of native bees in cities

2019 ◽  
Vol 15 (12) ◽  
pp. 20190574 ◽  
Author(s):  
Gordon Fitch ◽  
Caleb J. Wilson ◽  
Paul Glaum ◽  
Chatura Vaidya ◽  
Maria-Carolina Simao ◽  
...  
Keyword(s):  
Native Species ◽  
Negative Relationship ◽  
Native Bees ◽  
Urban Warming ◽  
Native Bee ◽  
Pollinator Conservation ◽  
Growing Body ◽  
Key Sites ◽  
Bee Communities ◽  
Bee Abundance

A growing body of research indicates that cities can support diverse bee communities. However, urbanization may disproportionately benefit exotic bees, potentially to the detriment of native species. We examined the influence of urbanization on exotic and native bees using two datasets from Michigan, USA. We found that urbanization positively influenced exotic—but not native—bee abundance and richness, and that this association could not be explained by proximity to international ports of entry, prevalence of exotic flora or urban warming. We found a negative relationship between native and exotic bee abundance at sites with high total bee abundance, suggesting that exotic bees may negatively affect native bee populations. These effects were not driven by the numerically dominant exotic honeybee, but rather by other exotic bees. Our findings complicate the emerging paradigm of cities as key sites for pollinator conservation.

scholarly journals Evaluating predictive performance of statistical models explaining wild bee abundance in a mass‐flowering crop

Ecography ◽  
2021 ◽  
Author(s):  
Maria Blasi ◽  
Ignasi Bartomeus ◽  
Riccardo Bommarco ◽  
Vesna Gagic ◽  
Michael Garratt ◽  
...  
Keyword(s):  
Statistical Models ◽  
Predictive Performance ◽  
Mass Flowering ◽  
Wild Bee ◽  
Bee Abundance

scholarly journals Good Things Come in Larger Packages: Size Matters for Adult Fruit-Feeding Butterfly Dispersal and Larval Diet Breadth

Diversity ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 664
Author(s):  
Geraldo B. Freire ◽  
Thayane Silva ◽  
Hernani Oliveira ◽  
Chloe Collier ◽  
Hanna P. Rodrigues ◽  
...  
Keyword(s):  
Body Size ◽  
Phylogenetic Signal ◽  
Large Population ◽  
Species Abundance ◽  
Generalized Least Squares ◽  
Species Traits ◽  
Diet Breadth ◽  
Dispersal Ability ◽  
Larval Diet ◽  
Dispersal Capacity

Introduction: In animals, body size is correlated with many aspects of natural history, such as life span, abundance, dispersal capacity and diet breadth. However, contrasting trends have been reported for the relationship between body size and these ecological traits. Methods: Fruit-feeding butterflies were used to investigate whether body size is correlated with species abundance, dispersal, permanence, and larval diet breadth in a Neotropical savanna in Brazil (Cerrado). We used Blomberg’s K and Phylogenetic Generalized Least Squares models (PGLS) to measure phylogenetic signal strength in species traits and to estimate size–dispersal–diet breadth associations, while also taking shared ancestry into account. Results: 539 individuals from 27 species were captured, and 190 individuals were recaptured, representing a 35% recapture rate. We found body size to be negatively associated with butterfly abundance, and positively associated with dispersal level, distance traveled, number of traps visited, individual permanence, and diet breadth. These results indicate that larger butterflies are more likely to disperse over longer distances. Moreover, larger butterflies have more generalized larval diets, based on the number of host plant families, genera, and phylogenetic diversity of the host plants they consume as larvae. Smaller butterflies rely on fewer resources, which is reflected in their higher survival in small patches and may explain their lower dispersal ability and higher diet specialization. Nevertheless, lower dispersal ability may, if not compensated by large population sizes, threaten small-bodied species inhabiting environments, such as the Cerrado, which have intense deforestation rates. Conclusions: Body size is positively associated with dispersal and diet breadth for the fruit-feeding butterflies collected in this study.

Sign in / Sign up

Export Citation Format

Share Document