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Agricultural expansion and intensification negatively affect pollinator populations and has led to reductions in pollination services across multiple cropping systems. As a result, growers and researchers have utilized the restoration of local and landscape habitat diversity to support pollinators, and wild bees in particular. Although a majority of studies to date have focussed on effects in pollinator-dependent crops such as almond, tomato, sunflower, and watermelon, supporting wild bees in self-pollinated crops, such as grapes, can contribute to broader conservation goals as well as provide other indirect benefits to growers. This study evaluates the influence of summer flowering cover crops and landscape diversity on the abundance and diversity of vineyard bee populations. We showed that diversity and abundance of wild bees were increased on the flowering cover crop, but were unaffected by changes in landscape diversity. These findings indicate that summer flowering cover crops can be used to support wild bees and this could be a useful strategy for grape growers interested in pollinator conservation as part of a broader farmscape sustainability agenda.

Supporting ecosystem services and conserving biodiversity may be compatible goals, but there is concern that service-focused interventions mostly benefit a few common species. We use a spatially replicated, multiyear experiment in four agricultural settings to test if enhancing habitat adjacent to crops increases wild bee diversity and abundance on and off crops. We found that enhanced field edges harbored more taxonomically and functionally abundant, diverse, and compositionally different bee communities compared to control edges. Enhancements did not increase the abundance or diversity of bees visiting crops, indicating that the supply of pollination services was unchanged following enhancement. We find that actions to promote crop pollination improve multiple dimensions of biodiversity, underscoring their conservation value, but these benefits may not be spilling over to crops. More work is needed to identify the conditions that promote effective co-management of biodiversity and ecosystem services.

Bees visit native and non-native plant species for pollen and nectar resources in urban, agricultural, and wildland environments. Results of an extensive survey of bee-flower collection records from 10 California cities from 2005-2011 were used to examine host-plant records of native and non-native ornamental plants to diverse native and non-native bee species; five cities were from northern California and five were from southern California. A total of 7,659 bees and their floral host plants were examined. Of these, 179 were Apis mellifera and 7,390 were non- Apis . Only four other non- native species (all in Megachilidae) were recorded in the survey, and together they accounted for 402 individuals. These bees have been databased in preparation for deposition in the University of California-Berkeley Essig Museum of Entomology. We identified 229 bee species and 42 genera visiting native and non-native plant types in urban areas. Of the 229 species, 71 bee species were collected from only native plants; 52 were collected from only non-native host plants; and 106 were collected from both types of plants. Native bee species were common on native plants and non-native plants, but there were substantially more non-native bee species visiting non-native plants compared to native plants. Flowering periods in months were similar for both types of plants, but non-natives tended to flower later in the year. We propose that using native and non-native plants improves habitat gardening by increasing opportunities for attracting a richer diversity of bee species and for longer periods. Knowing basic bee-flower relationships in an area is key to planning a bee habitat garden with a variety of plant types, regardless of their geographic origin. !!NOTE! Supplementary files can be found in the left menu (article tools)!!

Emergent fungal diseases are critical factors in global biodiversity declines. The fungal pathogenNosema bombiwas recently found to be widespread in declining species of North American bumble bees (Bombus), with circumstantial evidence suggesting an exotic introduction from Europe. This interpretation has been hampered by a lack of knowledge of global genetic variation, geographic origin, and changing prevalence patterns ofN. bombiin declining North American populations. Thus, the temporal and spatial emergence ofN. bombiand its potential role in bumble bee decline remain speculative. We analyzeNosemaprevalence and genetic variation in the United States and Europe from 1980, before an alleged introduction in the early 1990s, to 2011, extractingNosemaDNA fromBombusnatural history collection specimens from across this time period.Nosema bombiprevalence increased significantly from low detectable frequency in the 1980s to significantly higher frequency in the mid- to late-1990s, corresponding to a period of reported massive infectious outbreak ofN. bombiin commercial bumble bee rearing stocks in North America. Despite the increased frequency, we find no conclusive evidence of an exoticN. bombiorigin based on genetic analysis of globalNosemapopulations; the widespreadNosemastrain found currently in declining United States bumble bees was present in the United States before commercial colony trade. Notably, the USN. bombiis not detectably different from that found predominantly throughout Western Europe, with both regions characterized by low genetic diversity compared with high levels of diversity found in Asia, where commercial bee breeding activities are low or nonexistent.

Fire has a major impact on the structure and function of many ecosystems globally. Pyrodiversity, the diversity of fires within a region (where diversity is based on fire characteristics such as extent, severity, and frequency), has been hypothesized to promote biodiversity, but changing climate and land management practices have eroded pyrodiversity. To assess whether changes in pyrodiversity will have impacts on ecological communities, we must first understand the mechanisms that might enable pyrodiversity to sustain biodiversity, and how such changes might interact with other disturbances such as drought. Focusing on plant-pollinator communities in mixed-conifer forest with frequent fire in Yosemite National Park, California, we examine how pyrodiversity, combined with drought intensity, influences those communities. We find that pyrodiversity is positively related to the richness of the pollinators, flowering plants, and plant-pollinator interactions. On average, a 5% increase in pyrodiversity led to the gain of approximately one pollinator and one flowering plant species and nearly two interactions. We also find that a diversity of fire characteristics contributes to the spatial heterogeneity (β-diversity) of plant and pollinator communities. Lastly, we find evidence that fire diversity buffers pollinator communities against the effects of drought-induced floral resource scarcity. Fire diversity is thus important for the maintenance of flowering plant and pollinator diversity and predicted shifts in fire regimes to include less pyrodiversity compounded with increasing drought occurrence will negatively influence the richness of these communities in this and other forested ecosystems. In addition, lower heterogeneity of fire severity may act to reduce spatial turnover of plant-pollinator communities. The heterogeneity of community composition is a primary determinant of the total species diversity present in a landscape, and thus, lower pyrodiversity may negatively affect the richness of plant-pollinator communities across large spatial scales.

The purpose of this article is to challenge organizational scholars, management educators, and business leaders to consider more deeply the impact of global business activities on local ecosystems. Drawing on the management, sustainability, and entomology literature, we illustrate the complex relationship between global business and biodiversity loss through the lens of the commercial bumble bee trade. Global firms in this trade rear and supply bees for greenhouse crop pollination. We build on a well-known global strategy framework used in management education by adding a sustainability dimension, and offering propositions for the relationship between global business strategy and the strength of environmental sustainability. We conclude that a locally responsive, place-sensitive business strategy supports the strongest degree of environmental sustainability, and addresses the invisible compromises to ecosystem health that may result from the efforts of global firms to provide otherwise beneficial products and services.

Corporate social responsibility (CSR) embodies corporate concern for the natural environment. Biodiversity, however, is a relatively unfamiliar concept in the corporate lexicon, and comparatively little attention has been given to the effects of business on biodiversity and ecosystem health despite their fundamental role in human wellbeing. Adopting an interdisciplinary lens, we draw on the management, sustainability, and entomology literature to examine biodiversity as a CSR challenge highlighting the commercial bumble bee trade. We propose that Japan is emerging as a role model on the global stage as illustrated by its stakeholder approach to balancing commercial interests and ecological concerns associated with the global bumble bee trade. We conclude with implications for CSR. O CSR

In 2009 the USDA-NRCS asked the Urban Bee Lab at the University of California, Berkeley if urban bee-flower knowledge could be used to attract native bees to farms in Brentwood, Contra Costa Co. in Northern California. The overarching question was, could native bees play a role in supplementing honey bees by providing pollination services for crop flowers? If so, how many native bee species were visiting farms and how frequently did they occur?Eight small farms (4-60 ha) were selected to investigate this question; four were control and four were treatment farms where bee habitat gardens were constructed. Habitat gardens were stocked with native and non-native ornamental plants known to attract native bees (and honey bees).Bees were monitored yearly in spring at each farm from 2010-2016 to evaluate species richness and abundance, which yielded several findings:I. Farms near urban areas and a creek were consistently more attractive to diverse and abundant bee speciesII. Inconsistent bee garden maintenance and major changes in farm operations in other farms resulted in consistently lower measurements of bee richness and abundanceIII. Over the seven-year monitoring period, 144 bee species were recorded among all farmsIV. Nearby urban areas had most of the same species as the agricultural areas, suggesting a relationship of bees moving between two areasV. A total of 23 diverse native bee species were recorded from apple, berry, and cherry flowers, and many of them in substantial numbers, indicating that native bees were providing pollination servicesFinally, maintaining frequent professional contact with growers was considered crucial in conducting research over the long term. These contacts were also critical in designing outreach packages to growers who expressed interest in applying our native bee findings to their farming operations.

© 2016 John Wiley & Sons Ltd. Urbanization and agricultural intensification of landscapes are important drivers of global change, which in turn have direct impacts on local ecological communities leading to shifts in species distributions and interactions. Here, we illustrate how human-altered landscapes, with novel ornamental and crop plant communities, result not only in changes to local community diversity of floral-dependent species, but also in shifts in seasonal abundance of bee pollinators. Three years of data on the spatio-temporal distributions of 91 bee species show that seasonal patterns of abundance and species richness in human-altered landscapes varied significantly less compared to natural habitats in which floral resources are relatively scarce in the dry summer months. These findings demonstrate that anthropogenic environmental changes in urban and agricultural systems, here mediated through changes in plant resources and water inputs, can alter the temporal dynamics of pollinators that depend on them. Changes in phenology of interactions can be an important, though frequently overlooked, mechanism of global change.

There is compelling evidence that more diverse ecosystems deliver greater benefits to people, and these ecosystem services have become a key argument for biodiversity conservation. However, it is unclear how much biodiversity is needed to deliver ecosystem services in a cost-effective way. Here we show that, while the contribution of wild bees to crop production is significant, service delivery is restricted to a limited subset of all known bee species. Across crops, years and biogeographical regions, crop-visiting wild bee communities are dominated by a small number of common species, and threatened species are rarely observed on crops. Dominant crop pollinators persist under agricultural expansion and many are easily enhanced by simple conservation measures, suggesting that cost-effective management strategies to promote crop pollination should target a different set of species than management strategies to promote threatened bees. Conserving the biological diversity of bees therefore requires more than just ecosystem-service-based arguments.

Native bees are important ecologically and economically because their role as pollinators fulfills a vital ecosystem service. Pollinators are declining due to various factors, including habitat degradation and destruction. Grasslands, an important habitat for native bees, are particularly vulnerable. One highly imperiled and understudied grassland type in the United States is the Pacific Northwest Bunchgrass Prairie. No studies have examined native bee communities in this prairie type. To fill this gap, the bee fauna of the Zumwalt Prairie, a large, relatively intact remnant of the Pacific Northwest Bunchgrass Prairie, was examined. Native bees were sampled during the summers of 2007 and 2008 in sixteen 40-ha study pastures on a plateau in northeastern Oregon, using a sampling method not previously used in grassland studies—blue vane traps. This grassland habitat contained an abundant and diverse community of native bees that experienced marked seasonal and inter-annual variation, which appears to be related to weather and plant phenology. Temporal variability evident over the entire study area was also reflected at the individual trap level, indicating a consistent response across the spatial scale of the study. These results demonstrate that temporal variability in bee communities can have important implications for long-term monitoring protocols. In addition, the blue vane trap method appears to be well-suited for studies of native bees in large expanses of grasslands or other open habitats, and may be a useful tool for monitoring native bee communities in these systems.

Pathogens have been implicated as potential factors in the recent decline of some North American bumble bee (Bombus) species, but little information has been reported about the natural enemy complex of bumble bees in the United States. We targeted bumble bee populations in a state-wide survey in Illinois and several sites in California and Oregon where declines have been reported to determine presence and prevalence of natural enemies. Based on our observations, most parasites and pathogens appear to be widespread generalists among bumble bee species, but susceptibility to some natural enemies appeared to vary.

Concerns about pollinator declines have grown in recent years, yet the ability to detect changes in abundance, taxonomic richness, and composition of pollinator communities is hampered severely by the lack of data over space and time. Citizen scientists may be able to extend the spatial and temporal extent of pollinator monitoring programs. We developed a citizen-science monitoring protocol in which we trained 13 citizen scientists to observe and classify floral visitors at the resolution of orders or super families (e.g., bee, wasp, fly) and at finer resolution within bees (superfamily Apoidea) only. We evaluated the protocol by comparing data collected simultaneously at 17 sites by citizen scientists (observational data set) and by professionals (specimen-based data set). The sites differed with respect to the presence and age of hedgerows planted to improve habitat quality for pollinators. We found significant, positive correlations among the two data sets for higher level taxonomic composition, honey bee (Apis mellifera) abundance, non-Apis bee abundance, bee richness, and bee community similarity. Results for both data sets also showed similar trends (or lack thereof) in these metrics among sites differing in the presence and age of hedgerows. Nevertheless, citizen scientists did not observe approximately half of the bee groups collected by professional scientists at the same sites. Thus, the utility of citizen-science observational data may be restricted to detection of community- level changes in abundance, richness, or similarity over space and time, and citizen-science observations may not reliably reflect the abundance or frequency of occurrence of specific pollinator species or groups.

Evidence is mounting that pollinators of crop and wildland plants are declining worldwide. Our research group at UC Berkeley and UC Davis conducted a 3-year survey of bee pollinators in seven cities from Northern California to Southern California. Results indicate that many types of urban residential gardens provide floral and nesting resources for the reproduction and survival of bees, especially a diversity of native bees. Habitat gardening for bees, using targeted ornamental plants, can predictably increase bee diversity and abundance, and provide clear pollination benefits.

The potential pollinators of yellow starthistle (Centaurea solstitialis) were surveyed at six sites in north-eastern Oregon, USA, between May and September from 2000 to 2002. The objective of the study was to determine the species composition and relative abundance of the insects that visited yellow starthistle throughout the flowering season and to assess the pollen loads on their bodies in order to infer which species might be the most effective pollinators of this invasive plant species in north-eastern Oregon. A total of 1923 individual flower visitors were collected at the six sites over the 3 year study period, comprising four orders, 41 families, and 203 species of insects. The 20 most commonly collected species represented nearly 59% of the individuals and just ten of these species could be considered the key pollinators, judging by the combination of abundance and pollen carriage (the megachilids, Megachile apicalis (introduced) and Megachile perihirta, the apids, Apis mellifera (introduced), Bombus bifarius, Bombus centralis, Svastra obliqua, and Melissodes lutalenta, the halictids, Halictus tripartitus and Halictus ligatus, and the tachinid, Peleteria malleola. Over the 3 year study period, the six sites were consistently distinct in their flower visitor fauna, with the metropolitan Pendleton sites having a species composition distinct from the four mountain sites. Consistent patterns of interannual variation also were observed over the 3 year study. These patterns of flower visitation are interpreted in the context of the plant community within which yellow starthistle grows in north-eastern Oregon.

Gardens have become increasingly important places for growing nutritional food, for conserving biodiversity, for biological and ecological research and education, and for community gathering. Gardens can also be designed with the goal of attracting specific wildlife, like birds and butterflies, but pollinators, like bees, can also be drawn to specially planned and modified gardens. A community garden in San Luis Obispo, California provided the setting for modification with the goal of attracting native bee pollinators by planting known bee-attractive plants. The local gardeners participated in a survey questionnaire and focused interviews to provide their input and interest in such a project. Presentations on our work with native bees in urban environments and gardening to attract bees were also given to interested gardeners. Work of this type also benefited from a lead gardener who managed donated bee plants and kept up momentum of the project. Modification of the garden and monitoring of native bees started in 2007 and continued through the growing season of 2009. Diversity of collected and observed native bees has increased each year since 2007. To date, 40 species in 17 genera of mostly native bees has been recorded from the garden, and this number is expected to increase through time.

In mid 2003 a diverse floral resource was planted in a small urban residential plot at the University of California, Berkeley Oxford Tract with the goal of attracting local native California bee species to assess emerging patterns of diversity and seasonality. A standard procedure was then used in 2004 to sample the bees and monitor their host flowers. Pollen and nectar resources were abundant and consistently available during spring, summer, and early fall months of that year. Thirty-two bee species representing 17 genera, and five families used these resources through the 2004 season. Urban bees were categorized into three seasonalities: early season, late season, and full season represented by seven, eight, and 17 species respectively. Results of this study indicate that newly-planted urban gardens, which are designed for bees, have the potential to attract diverse seasonal bee taxa if diverse floral resources are provided throughout the growing season. Implications of these finding are discus...

A survey of the bee species and their ornamental host flowers that occur in residential neighborhoods of the cities of Albany and adjacent Berkeley in northern California was conducted from 1999–2003. A simple bee frequency (visitation) count was developed to evaluate the relative attraction of bees to their host flowers. Results of the survey revealed that 76 species of bees, mostly natives, from five families, visited 129 host plants at measurable levels. The most common host plant families were Asteraceae, Lamiaceae, Polygonaceae, Rosaceae, and Scrophulariaceae. Honey bees and all other bee taxa were recorded separately on host plants, and both bee groups were more attracted to California native plants than exotics on a percentage basis. Variable attraction was recorded within native and exotic host plants, and a large part of this variation appears related to where the plants are found in residential areas. In general, the highest bee diversity and abundance was observed in diverse gardens ha...

The subgenus Onagrandrena was first recognized and described by Linsley and MacSwain (1956) to include those black Andrena that are oligolectic on plants of the family Onagraceae and have pollen-collecting hairs modified to collect the specialized pollen from those plants. The males are more difficult to recognize than the females and most males are very similar to those of Melandrena. Since first described, two species of Onagrandrena have been recognized that have pale vestiture in both sexes. However, the pollen collecting hairs of both of these are of the Onagrandrena type, both sexes have well-formed pronotal angles and lateral ridges, and the males have relatively narrow, long mandibles with reduced or absent subapical teeth. The species of Onagrandrena are very similar and are difficult to tell apart. Populations seem to be relatively isolated in desert locations with habitats amenable to the host plants. This, we believe, has led to a proliferation of species and we can detect slight average differences between populations from different geographic locations within some species. A few of these microgeographic races have been recognized in the literature as subspecies, but the present authors prefer not to formally recognize these races with names. The reader is referred to earlier sections of this revision (LaBerge l967, l969, l97l, 1973, l977, l980, l986, l989; LaBerge and Bouseman 1970, 1987; LaBerge and Ribble 1972, 1975; Bouseman and LaBerge 1979; Thorp, 1969; Donovan, 1977) for details of morphology and for a more complete bibliography of the literature on Andrena. No new morphological terms have been introduced in the present work and the bibliography presented includes only references cited in the text or not listed in earlier parts of the revision. Published locality and floral records are included in the appropriate sections near the end of each species account. Maps showing the known distributions of species (Figs. 2-6) do not have all listed localities spotted on them. Localities that could be located only in a general way, such as county, or could not be found on maps or in gazetteers are omitted. Considerable detailed information is available concerning the floral activity of several species of Onagrandrena in papers by Linsley, MacSwain, Raven and Thorp (1963a and b, 1964) and MacSwain, Raven, and Thorp (1973). These papers also provide brief notes on nesting burrows and an earlier paper by Linsley, MacSwain and Smith (1955) gives details on the nesting biology of a few species of Onagrandrena.

Managing ecosystem services is critical to human survival, yet we do not know how large natural areas must be to support these services. We investigated how crop pollination services provided by native, unmanaged, bee communities varied on organic and conventional farms situated along a gradient of isolation from natural habitat. Pollination services from native bees were significantly, positively related to the proportion of upland natural habitat in the vicinity of farm sites, but not to any other factor studied, including farm type, insecticide usage, field size and honeybee abundance. The scale of this relationship matched bee foraging ranges. Stability and predictability of pollination services also increased with increasing natural habitat area. This strong relationship between natural habitat area and pollination services was robust over space and time, allowing prediction of the area needed to produce a given level of pollination services by wild bees within this landscape.

Author(s): Forrest, JRK; Thorp, RW; Kremen, C; Williams, NM | Abstract: Land-use change frequently reduces local species diversity. Species losses will often result in loss of trait diversity, with likely consequences for community functioning. However, the converse need not be generally true: management approaches that succeed in retaining species richness could nevertheless fail to maintain trait diversity. We evaluated this possibility using bee communities in a California agroecosystem. We examined among site patterns in bee species diversity and functional-trait diversity in a landscape composed of a mosaic of semi-natural habitat, organic farms and conventional farms. We sampled bees from all three habitat types and compiled a data base of life-history ('functional') traits for each species. Although species richness was higher on organic farms than conventional farms, functional diversity was lower in both farm types than in natural habitat. Nesting location (below-ground vs. above-ground) was the primary trait contributing to differences in functional diversity between farms and natural habitat, reflecting observed differences in availability of nesting substrates among habitat types. Other traits, including phenology and sociality, were also associated with species' occurrences or dominance in particular site types. These patterns suggest that management practices common to all farms act as environmental filters that cause similarly low functional diversity in their bee communities. Synthesis and applications. Although our results support the value of organic farming in maintaining abundant and species-rich bee communities, components of bee functional diversity are not well supported in farmed landscapes, regardless of farming practice. Maintenance of natural habitat, and/or the addition of natural habitat elements to farms, is therefore important for the retention of functionally diverse bee assemblages in agroecosystems. Although our results support the value of organic farming in maintaining abundant and species-rich bee communities, components of bee functional diversity are not well supported in farmed landscapes, regardless of farming practice. Maintenance of natural habitat, and/or the addition of natural habitat elements to farms, is therefore important for the retention of functionally diverse bee assemblages in agroecosystems.

© 2015 Macmillan Publishers Limited. All rights reserved. There is compelling evidence that more diverse ecosystems deliver greater benefits to people, and these ecosystem services have become a key argument for biodiversity conservation. However, it is unclear how much biodiversity is needed to deliver ecosystem services in a cost-effective way. Here we show that, while the contribution of wild bees to crop production is significant, service delivery is restricted to a limited subset of all known bee species. Across crops, years and biogeographical regions, crop-visiting wild bee communities are dominated by a small number of common species, and threatened species are rarely observed on crops. Dominant crop pollinators persist under agricultural expansion and many are easily enhanced by simple conservation measures, suggesting that cost-effective management strategies to promote crop pollination should target a different set of species than management strategies to promote threatened bees. Conserving the biological diversity of bees therefore requires more than just ecosystem-service-based arguments.