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• Flower-rich road verges increase flower visitors in surrounding landscapes. • Despite similar visitor numbers, pollination success is lower closer to road verges. • High traffic intensity can reduce flower visitor abundance in surrounding landscapes. • Conserving floral resources in road verges supports pollinator communities. Flower-visiting insects and the plants that depend on them are declining due to habitat loss and deterioration. Road verges, which often provide abundant floral resources, are gaining attention for their potential conservation value, as they can support a high abundance and diversity of flower-visiting insects. Thereby, flower-abundant road verges may benefit pollination in surrounding landscapes. However, the potential negative effect of traffic on this benefit remains unexplored. We addressed the research gap using potted wild strawberry plants (Fragaria vesca , variety 'Rügen'), placed at 20 m and 80–100 m distance from road verges along roads with varying traffic intensity (around 100–5500 vehicles per day). We found that floral abundance in road verges enhanced the number of flower visitors to strawberry plants in nearby areas, regardless of the distance to the road verge. However, this positive effect was restricted by increasing traffic intensity and narrower road verge width. Despite similar numbers of flower visitors at both distances, the pollination success, measured as the number of developed achenes on each harvested strawberry, tended to be lower closer to the road verge than further away but was unrelated to flower density, traffic intensity and road verge width, which indicates potential differences in pollinator behaviour or in the pollen they carried. Our findings highlight the potential of flower-rich road verges to support the conservation of flower-visiting insects. However, we emphasise the need to consider road verge width and traffic intensity to ensure successful pollinator-friendly management. [ABSTRACT FROM AUTHOR]

The key role of wild bees in providing pollination services is well recognized. Most wild bees nest in the ground and need suitable nesting habitat to thrive. Despite covering 14 million km2 of the world's surface, the potential of arable land as a nesting habitat has been largely neglected, although studies indicate that ground-nesting bees nest in arable soils. Therefore, it is important to understand the impact of tillage on bees' nesting and reproductive success. Here, we synthesize the existing knowledge of potential consequences and mechanisms underlying tillage effects on ground-nesting bees, identify knowledge gaps, and propose directions and approaches for future research. Our literature review has identified ten studies that directly or indirectly assessed impacts of tillage on ground-nesting wild bees in arable cropping systems, showing either no effect or a negative effect of tilled compared to no-till systems. Potential tillage effects include direct impacts related to physical injury of bees, offspring, and brood cells, destruction of nest burrow architecture, displacement of brood cells, and alteration of soil environmental conditions surrounding brood cells, as well as indirect effects related to soil cover, soil properties, and soil conditions. Our review highlights that we poorly understand how tillage influences bee nesting incidence, survival, emergence timing, offspring sex ratio, and, in the longer term, community composition. In particular, it remains unclear whether tilled arable soils are suitable nesting habitat or ecological traps for ground-nesting bees. To address these research gaps, we propose methods to directly quantify nesting and emergence of bees, and (semi-)field and laboratory experiments that allow to disentangle mechanisms driving tillage effects. Improved understanding of tillage effects and underlying mechanisms will help to develop more effective strategies to promote ground-nesting wild bees and the crop-pollinating and soil ecosystem services they provide through their foraging and nesting activities. • Various ground-nesting wild bee species nest in arable soils. • Review of effects of tillage and underlying mechanisms on ground-nesting bees. • Several direct and indirect tillage impacts on bee nesting and survival highlighted. • Novel methodological approaches are proposed to better understand tillage effects. • Understanding tillage impacts is needed to improve agricultural policy. [ABSTRACT FROM AUTHOR]

Human activities, particularly urbanization, profoundly impact ecosystems often resulting in biotic homogenization. Whether or not urban landscapes can sustain diverse pollinator and plant communities is an important question to be addressed. Here, we investigated the influence of urbanization on plant-hummingbird interaction networks in a large tropical city, Belo Horizonte, Brazil. We recorded 13198 legitimate interactions between seven hummingbirds and 57 plant species across 12 local networks. Urban landscapes exhibited predominantly generalized networks, maintaining this pattern across varying vegetation cover and floral resource abundance. Although some functionally specialized hummingbirds with long bills were recorded performing more specialized interactions, urban environments did not generally support specialized networks. Nevertheless, network specialization did increase with the proportion of native nectar plants, emphasizing their importance for maintaining some specialized interactions. Furthermore, we observed a positive effect of plant richness, but not of flower abundance, on hummingbird abundance, indicating that it is not only the amount of flowers, but the diversity of floral resources that may be a key factor in maintaining hummingbirds. Therefore, promoting a diverse assemblage of native plants in urban green areas is crucial for sustainable pollinator communities. Our study highlights that while a biodiverse urban landscape will require careful urban vegetation planning considering both floral resource diversity and availability, vegetation cover per se may not be sufficient to mitigate the negative impacts of urbanization. Maintaining a diverse vegetation with different life forms, flowering phenology, and especially of native plants across the urban landscape is needed to create welcoming spaces for pollinators. [Display omitted] • Hummingbirds are important pollinators found in urban areas across the Americas. • Generalized interaction networks predominated across the urban landscape. • Specific types of vegetation should be considered in urban green spaces. • Importance of native flora to support specialized interactions for hummingbirds. [ABSTRACT FROM AUTHOR]

The yield of many agricultural crops depends on pollination services provided by wild and managed bees, many of which are experiencing declines due to factors such as reductions in floral resources. Thus, improving pollinator habitat on farmlands using management strategies like planting wildflower strips is vital for wild bee conservation and sustainable crop pollination. Yet, few studies have examined whether and at what spatial scales wildflower strips enhance crop pollination and yields, and most research has been conducted in large-scale commercial agriculture. Therefore, we investigated the effects of wildflower strips on crop pollination on small, diversified farms (i.e., those growing a variety of crop species) where wild bee diversity and abundance is predicted to be comparatively high. Over three years, on four diversified farms in Montana USA, we tested the hypothesis that distance (20, 60, and 180 m) of crops from native perennial wildflower strips planted alongside crop fields affected wild bee visitation, pollination, and yields of squash and sunflower crop plants. We found that distance to wildflower strips did not affect bee visitation or pollination in crops. Squash yield was pollen-limited in the growing season prior to wildflower strip establishment, and in one of the two years after wildflower strip establishment, but proximity to wildflower strips did not influence the magnitude of pollen limitation. Sunflower seed production was not pollen-limited in any year. Our findings demonstrate that even on diverse farms with wildflower strips and a demonstrated high diversity of bees, some crops do not necessarily receive maximum pollination, regardless of distance from the wildflower strips. However, the value of wildflower strips for supporting wild bee diversity, and other ecological or economic benefits, needs consideration for a full understanding of this pollinator habitat management strategy. [ABSTRACT FROM AUTHOR]

• Pollinator conservation is a topic of public concern. This study analyses public comments on policy to determine stance, sources, and main concerns. • We found the greatest concerns were for bees and pollination, but that the diversity of bees their role in pollination was not well understood. • Regulation of neonics and other actions to protect pollinators have broad which creates a rare opportunity for conservation policy and action. • We found very strong support for neonicotinoid regulation, with less than 5% opposed to the proposed policy. • We conclude to be effective support will need to be translated into evidence-based policy that addresses the threats at-risk pollinators face. Pollinator conservation is a major focus of current conservation attention and public policy. However, an understanding of the social dimensions of pollinator conservation is urgently needed for effective action. In 2014, Ontario became the first jurisdiction in North America to propose to regulate neonicotinoid pesticides, and the proposal included a draft Pollinator Health Action Plan with additional measures to protect pollinator species. We analyzed the 972 comments submitted on the proposal by individual citizens, determining each commenter's stance, source of information (if applicable), and main concerns. We found very strong support for neonicotinoid regulation, with less than 5% opposed. We also found that the greatest concerns were for bees and pollination services, but that the diversity of pollinating species and the relative contributions of various taxa to pollination was not well understood. Government regulation of neonicotinoid pesticides and other actions to protect pollinator health clearly have the broad support and great interest of the general public, which creates a rare opportunity for conservation policy and action. We conclude that, in order to be effective, broad support will need to be translated into nuanced, evidence-based policy that is focussed on native species and addresses the many threats at-risk pollinators face. [ABSTRACT FROM AUTHOR]

Biodiversity conservation is fundamentally linked to human values, attitudes, and behaviours. Nature connectedness, the strength of a person's relationship with nature, is an important determinant of pro-nature actions, and therefore vital for counteracting biodiversity loss. Citizen science may improve nature connectedness, though such outcomes are underexplored in comparison to scientific and educational results. Addressing this gap, we studied the experiences of participants in the Big Butterfly Count, a UK mass-participation citizen science activity that aims to raise awareness and gather data on the abundance of widespread butterfly and moth species. Participants completed surveys before and after the three-week Big Butterfly Count period (n = 382), and at six- to seven-week follow up (n = 345). Improvements in nature connectedness, decreased anxiety, and increased tendency to notice nature and butterflies, were found immediately after the count period, with improved wellbeing and nature noticing at follow-up. Stronger emotional responses during the butterfly count were associated with greater increases in nature connectedness and nature noticing. Qualitative data revealed mixed emotions, from sadness and concern about biodiversity loss, to feelings of hope and optimism through taking actions to help butterflies. These findings suggest that citizen science participation prompts people to notice and enjoy nature in ways that enhance their wellbeing and connection with nature, supporting the mutual health of people and the rest of the natural world. The study highlights the potential for nature-based citizen science to benefit conservation beyond the focal species or habitat, by changing how people think, feel and act towards nature more broadly. • Citizen science research rarely considers nature connectedness, an important driver of pro-conservation behaviours. • A quasi-experimental design explored the impact of citizen science participation on nature connection and wellbeing. • Big Butterfly Count participation increased nature connectedness and nature and butterfly noticing, and decreased anxiety. • Stronger emotional experiences were associated with greater increases in nature connection and nature noticing. • By improving human-nature relationships, citizen science makes important contributions to biodiversity conservation. [ABSTRACT FROM AUTHOR]

The mountains of Central Appalachia are rich with environmental variance and host a wide variety of community types and diverse flora and fauna. The once common rusty patched bumble bee (RPBB, Bombus affinis) has experienced widespread declines and was believed to have been extirpated throughout the Lower Midwest, Northeast and Appalachian regions of the United States (U.S.). We document the occurrence and environmental associations of a contemporary population within Central Appalachia using a dataset of 274 observations spanning nine years and over 2100 surveys. We show that Appalachian RPBB are strongly associated with high elevation, heavily forested landscapes, especially those with West to Northwest facing aspects. Within forests, the basal area of oak and pine was positively associated with RPBB detection. While only 38% of surveys occurred on U.S. National Forest lands, 84% of observations occurred in these areas, suggesting distinct forest habitat conditions associated with U.S. Forest Service lands play a role in the persistence of this species. The Appalachian region is rugged and difficult to survey systematically, and our analysis is the first assessment of the species presence and habitat associations within the region. Appalachian RPBB populations are likely geographically and genetically isolated from Upper Midwest populations and additional research is needed to prioritize future conservation efforts across the current and potential range of the species. • In one of the few manuscripts produced since the rusty patched bumble bee (RPBB; B. affinis) was listed, we examine how forested habitat in montane Central Appalachia is associated with populations of the endangered RPBB using nine years of data and over 2100 surveys. • Our work provides unprecedented insights into an apparently disjunct population and demonstrates strong associations with forested habitat. • Unlike populations in the Upper Midwest, an area considered to be the core of the current range, Appalachian RPBB do not show associations with urban or grassland habitat. • Observations are heavily enriched on U.S. National Forest lands and are strongly associated with forest extent and composition at the landscape scale. [ABSTRACT FROM AUTHOR]

To mitigate the effects of habitat loss on bee conservation and crop pollination, farmers are encouraged to plant flowers along the edges of crop fields. However, it is unclear where and to what degree these flower plantings are effective. Recent studies suggest that flower plantings may be less effective if they are established in landscapes with either very low or very high amounts of non-crop habitat. Moreover, while field edge flower plantings often increase the abundance and richness of bees in field edges, it is unclear whether this improves crop pollination or bee nesting success, which could increase bee populations over time. In this study we examined how field edge flower plantings and the landscape context in which they are established affect wild bee conservation and crop pollination. Across two years we established flower plantings of 0.1–0.5 ha along the edges of 17 of 34 commercial cucumber fields arranged across a gradient of landscape complexity. We then measured wild bee abundance, richness, and crop pollination in and around cucumber fields with and without plantings and assessed the nesting success of stem-nesting bees. We found that both field edge flowers and landscape-scale non-crop habitat had independent, positive effects on bee abundance, richness, nesting, or crop pollination in one of the two years of the study, and that the effects of field edge flowers on bees and crop pollination were not influenced by the surrounding landscape. We also found that managing field edges in a way that maintains naturally-occurring flowers may matter as much or more than flower plantings for short-term increases in bee abundance and richness. However, certain species of planted flowers might be associated with improved bee nesting success, an outcome important for both bee conservation and sustained crop pollination. • Examined how flower plantings and landscape affect wild bees and crop pollination. • Local flowers and surrounding landscape had positive effects in 1 of 2 study years. • Effects of field edge flowers were not influenced by the surrounding landscape. • Managing field edges to maintain naturally occurring flowers is important. • Local flowers may improve success of stem-nesting bees. [ABSTRACT FROM AUTHOR]

Abstract The act of converting prairie grassland to agricultural farmland has negative implications for pollinator communities. In the Prairie Pothole Region, wetland remnants are a common feature in intensively cultivated landscapes. These wetlands are typically small and often left embedded in the cropland matrix and may act as the only semi-natural feature in a radius of several hundred metres. To quantify the role that these in-field wetlands play in supporting native pollinators, we sampled bees at three distances from the wetland margin into the surrounding cropland (0 m, 25 m and 75 m) across the season in three field types (canola, cereal and perennial grassland). We used Bayesian multilevel models to test the hypothesis that native bees are using infield wetlands as habitat for nesting and foraging. Native bee abundance and diversity decreased further away from the margin of wetlands in both canola and cereal fields, while it increased in wetlands located in perennial grassland. Community composition did not change further away from wetlands, which may be because the foraging range of most species was within the sampling distance of the study. These results suggest that wetlands play an important role in providing critical resources for native pollinators, and encouraging farmers not to drain or plow through these wetlands will have beneficial impacts for native pollinators in the area. Maintaining in-field wetlands may have additional pollination benefits for farmers growing crops such as canola, which is known to benefit from insect visitors. [ABSTRACT FROM AUTHOR]

Targeted conservation and promotion of wild bees in agroecosystems requires understanding of relationships between different groups of bees and available floral resources across land-use types during the season and at the landscape scale. Here, we quantified floral resource amount and diversity across habitat types at different times during the season at the scale of entire landscapes (500 m radius) across 20 different agricultural landscapes. Moreover, we examined whether floral resource metrics obtained from these high-resolution floral resource maps are more suitable to assess and predict abundance and species richness of different bee pollinator groups, including rare species and important crop pollinators, sampled in these agricultural landscapes compared to traditional land-cover metrics. Floral resource availability shifted from flower-rich woody vegetation early in the season to herbaceous vegetation such as grasslands and crops later in the season, which was associated with a ten-fold decline in overall floral resource availability. Forest edges had highest per-area floral contributions in spring, whereas floral diversity of grasslands, in particular if extensively managed, was continuously high. Total wild bee species richness, as well as rare species richness and abundance of important crop pollinators, increased with floral resource availability and/or diversity contributed by forest edges and floral diversity of permanent grasslands. Rare bee richness was also positively related to floral resource amount provided by crops. Total bee richness and important crop pollinator abundance, but not rare bee richness, were positively related to overall floral resource amount, but not floral diversity, in the landscape. Floral resource maps based on floral resource supply by major habitat types early or late in the season predicted wild bee species richness (R 2 =0.61) better than traditional descriptors of landscape composition such as proportion of semi-natural habitat. The pronounced temporal shifts in floral resource availability for pollinators from woody towards herbaceous vegetation during the season highlights the importance of taking a landscape-scale perspective on pollinator conservation. Our findings indicate that both rare bees and important crop pollinators benefit from complementary floral resources of forest edges and grasslands in agroecosystems. This reveals a potential synergy between the conservation of endangered species and the landscape scale management to promote pollination services. Our study also highlights that floral resource maps are useful tools in supporting more targeted pollinator conservation and pollination service management at the landscape level. • Floral resource complementarity across habitats during the season supports bees. • Pronounced floral resource shifts from woody to herbaceous vegetation during season. • Floral resources of forest edges and grasslands key for rare bees and crop pollinators. • Floral resource maps better predict wild bees than landscape composition. • Functional resource maps are useful tools for targeted pollinator conservation. [ABSTRACT FROM AUTHOR]

Urban greenspaces are recognized as a benefit to pollinator conservation. Selective planting of attractive flowering plants can improve the conservation value of urban greenspaces. However, the functional traits of flowering plants that moderate pollinator preference merits further study. We analyzed 98 ornamental plants and spontaneous plant species for ten categories of floral and plant traits across twelve parks or campus greenspaces in Wuhan, a megacity located in central China. Our results revealed that: (1) Plant species vary enormously in their pollinator visitation rate. (2) For Lepidoptera, the number of individuals to the plot was lower for disk/bowl-shaped flowers than other flower shapes, and it was negatively corelated with corolla tube length. The number of Diptera individuals to the plot was higher for white, red/pink and yellow/orange flowers than blue/violet flowers. (3) Honeybees preferred exotic annual/biennial herbaceous species, with disk/bowl and flag flowers. Solitary bees preferred horizontal, lip or flag flowers. Diptera most frequently visited upward-facing, yellow/orange flower heads and Lepidoptera preferred horizontal, funnel-shaped flowers or flower heads. Blue/violet flowers and a diverse floral orientation were preferred by most pollinator groups. We recommend planting native woody plants (Nandina domestica , Thymus quinquecostatus , Lagerstroemia indica , and Tamarix austromongolica) and attractive exotic plants (Centaurea cyanus, Borago officinalis, Portulaca grandiflora , and Echinacea purpurea) to support multiple pollinator groups. As preferences differ among pollinators, increasing the species richness of flowering plants is conducive to promote overall pollinator diversity. • Flower shape may be the most important floral traits for attracting pollinators of the flowering plants in urban greenspaces. • Some native woody plants and attractive exotic plants are recommended to enhance the value of urban greenspace in sustaining biodiversity for a subtropical city. [ABSTRACT FROM AUTHOR]

Highlights • Post-wildfire salvage logging reduced reproductive potential of snowberry. • Reduced reproductive potential due to abiotic conditions, not biotic pollination. • Actual (realized) snowberry reproduction was similar between logged and unlogged. • Pollination experiments with observations provide useful approach to logging effects. • Legacies of post-wildfire logging on understory reproduction can persist for decades. Abstract Post-wildfire salvage logging is an increasingly used land management tool with poorly understood ecological consequences for understory flowering plants and their interactions with pollinators. Understanding these consequences of salvage logging is important because an essential aspect of post-wildfire forest succession involves pollination and plant reproduction. For snowberry (Symphoricarpos albus), an ecologically-important and fire-tolerant shrub, we tested the long-term effects of post-wildfire logging on plant reproduction and pollen limitation using a supplemental-pollen experiment coupled with pollinator observations of S. albus and of potential co-flowering competitors of S. albus. Nearly a quarter century after these disturbances, we found no effects of post-wildfire logging on the reproduction of naturally-pollinated plants. The reproduction of some S. albus individuals were pollen limited, but only in unlogged areas, suggesting that plants in unlogged areas have higher potential reproduction compared to those logged areas but are unable to achieve this higher level of reproduction due to lack of pollination. This pollen limitation of S. albus reproduction is consistent with the relatively high floral densities of potential competitors of S. albus and generally low pollinator visitation rates in unlogged areas. Together, these results suggest that legacies of post-wildfire logging may restrict the reproductive potential of this shrub for at least several decades after the logging is complete, but this restriction is likely due to altered abiotic conditions and not via lack of pollination. [ABSTRACT FROM AUTHOR]

Responses of hoverflies (Diptera: Syrphidae) to climate change remain mostly unexplored. Here, for the first time, we investigate the impact of climate change on both presence/absence and abundances of hoverfly species. We used generalized linear models to analyse the relationships of climatic and soil variables with the occurrence and abundance of Cheilosia species on the Balkan Peninsula. Our results show that the ranges of all and the abundances of many species are projected to decrease in the future. Climatically suitable conditions for mountainous species are predicted to generally shift northwards. Species adapted to high mountains are projected to almost vanish from the Balkans and only regions of the Alps would remain suitable for them. We found climatic variables were more important in determining abundance than occurrence. Given that environmental factors differed in terms of their impact on abundance and occurrence, we highlight the importance of monitoring both parameters to ensure effective conservation. Considering the different projected responses of hoverflies to future climate change, as well as their value as pollinators and the increasing threats they currently face, knowledge on their responses to the major drivers of their life-histories is indispensable for proper management and conservation action. We reveal that nationally-designated protected areas are insufficient to conserve the species considered here, both currently and under projected climate change. We recommend implementation of an integrated conservation management plan that can provide a continuum of protected areas along the Dinaric mountain chain to facilitate movement of species to enhance species survival. [ABSTRACT FROM AUTHOR]

Pollination is a key ecosystem service. Pollinators, however, are in decline and their service is increasingly threatened. The decline is driven by several factors, most of which are related to agricultural management. However, the complexity of the landscape system, consisting of both cropped and non-cropped areas, makes it difficult to address or even quantify the role of farming practices in pollinator abundance. Therefore, the aim of this paper is to improve our understanding of the relationships between pollinator abundance and their habitat use. We intend to identify and quantify the driving environmental factors that determine pollinator abundance in agricultural landscapes on the crop and landscape scale. These information helps us to design algorithms that can be used as a basis for predicting pollinator abundance on agricultural fields. To integrate varying environmental conditions data sampling was performed on farms in three different regions in Germany. Pollinators were classified into different groups with three aggregation levels. We observed crop parameters as well as landscape parameters in the areas surrounding fields in addition to temporal aspects. Generalized linear models (GLMs) were then calculated. Our results showed that both crop and landscape parameters affect pollinator abundance on agricultural fields. However, the explanatory power of the included parameters varied strongly among the particular pollinator groups and between aggregation levels. Furthermore, differentiation between species groups improves the explanatory power compared to models that are more aggregated. We also found that the temporal match between main activity periods of the particular pollinator groups and resource supply by the crop species is a key factor when analysing pollinator abundance. In conclusion, we demonstrated that the assessment and support of pollination services should be carried out with regard to individual pollinator groups. When studying pollinator abundance, the crop as well as the landscape scale should be addressed. A range of different habitat requirements and different activity periods of the pollinator groups must be covered to maintain pollination services, and therefore both diverse landscapes and diverse crop rotations are of crucial importance. [ABSTRACT FROM AUTHOR]

Urbanization leads to the restructuring of plant-animal interactions due to environmental changes and introduction of non-native species that become part of local ecological processes. The conservation of pollinators in urban areas has received increasing attention. However, detailed quantification of available floral resources and their use by pollinators are rarely conducted. Here, we characterized the interaction network between hummingbirds and native and non-native plants, the behavior of resource use by pollinators and the temporal availability of nectar resources in an extensive urban green area from Brazil. We found that more than half of the interactions between hummingbirds and plants were illegitimate, which do not constitute potential pollination. The interaction network was generalized, indicating low level of niche partitioning, which is usual for urban environments. Inclusion of non-pollination interactions increased specialization. Although native and non-native plants provide a similar amount of nectar when considering each plant species for a given month, the latter contributed most to the total nectar availability owed to their higher abundance and longer flowering phenologies. Importantly, non-native plants provided resources when native flowers were scarce. Our results show how non-native plants may sometimes have relevant contributions for maintenance of pollinators in cities throughout the year, supporting them during periods of resource shortage. At the same time, urban pollinator-plant communities may be characterized by high prevalence of illegitimate interactions, which highlights the opportunistic use of resources by animals. In conclusion, our study suggests that biodiversity-friendly urban planning should consider the relevant role played by non-native species and that pollinator support may require different types of interactions with flowers. • We quantified temporal nectar availability and use by hummingbirds. • Non-native plants contributed substantially to nectar availability. • Native and non-native plants showed distinct phenologies. • Most visits were illegitimate, without touching the reproductive structures. • Pollinator conservation in urban areas should consider non-mutualistic interactions. [ABSTRACT FROM AUTHOR]

• This work aims to compare the effects of three types of floral margins (managed herbaceous, managed shrubby, and unmanaged herbaceous) on the abundance and diversity of bees in order to propose a management strategy for the conservation of pollinating insects. • Managed margins supported higher abundances and richness than unmanaged ones, and specifically, supported at least 30% more rare bee genera than unmanaged margins. • Here we highlight the importance of floral margins management for the enhancement and conservation of bee communities, restoring habitat and food resources for pollinators across the Mediterranean agricultural landscape. Floral resources on crop field margins are a well-accepted measure to increase bee abundance in agricultural landscapes. However, studies have mainly focused on managed margins, while studies on the effect of unmanaged floral margins for the conservation of bees are still scarce. This work aims to test and compare the effects of three types of floral margins (managed herbaceous, managed shrubby, and unmanaged herbaceous) on the abundance and diversity of bees in order to propose a management strategy for the conservation of pollinating insects. Bee abundance was recorded by visual samplings in plots of 2 × 2 square meters over two years in the three margin types in four localities in southern Spain. The diversity of plant species and the flowers they supported were measured to explain the associated bee communities. Differences in the relative abundances of bee families and the number and abundance of bee genera were observed between margin types. Andrenidae was generally more abundant in the herbaceous margins regardless of whether these were managed or not. With the exception of the Halictidae, the majority of bees families (wild Apidae, Apis mellifera , Colletidae and Megachilidae) were more abundant in the managed than unmanaged margins. Moreover, the number of bee genera was higher in managed than in unmanaged margins. In addition, here we show that managed margins supported at least 30% more rare bee genera than unmanaged margins, highlighting the importance of floral margins management for the enhancement and conservation of bee communities, restoring habitat and food resources for pollinators across the Mediterranean agricultural landscape. [ABSTRACT FROM AUTHOR]

Results-based agri-environmental schemes (AES) seek to overcome reluctance to adopt other forms of AES in the European Union. Instead of complying with inflexible land management prescriptions, farmers receive payments after certain contracted environmental results are verified. In addition to reducing the organizational and administrative burdens, this practice allows farmers to focus on which practices can achieve the desired environmental outcomes. Farmer uptake of results-based payments may be limited by risk-adverse behavior, such as fear of not meeting environmental targets and forfeiting the contracted payment. This study investigated participation in a hypothetical results-based AES among arable farmers in the German state of North Rhine-Westphalia and the number of hectares enrolled (participation intensity). Our hypothetical scheme sought to foster biodiversity in pollinator and bird species by supporting weed-species richness in intensive arable production. Our split-treatment research design investigated how social nudging influences acceptance and intensity. Approximately 60% of the 63 farmers in our convenience sample expressed a willingness to participate in our hypothetical scheme. Using a Heckman style selection model, we could not detect any effect of the social nudge tested on the likelihood of participation or its intensity. Cognitive factors correlated positively with the likelihood of participation, whereas social and dispositional factors correlated with participation intensity. Perceived lack of control was the main obstacle found to adoption. The findings suggest that policies can mitigate barriers to acceptance by reducing the bureaucratic burden and being transparent over expected costs and ecosystem benefits. This study was the first to investigate farmers' acceptance of a hypothetical results-based AES that targets the enrichment of biodiversity in arable farming and thus may serve as a stepping stone for follow-up studies. • We investigated arable farmers' perceptions about a hypothetical results-based AES. • We could not detect an effect of a social nudge on scheme acceptance. • Cognitive factors relate to farmers' participation in results-based AES. • Social factors relate to the decision of how much land to enroll in the AES. • Largest barrier to participation was the perceived bureaucratic burden. [ABSTRACT FROM AUTHOR]

Highlights: [•] Field beans are pollinated by a few important bumblebee species. [•] Oilseed rape is pollinated by a diverse insect community which varies spatially and temporally. [•] Managment to improve pollination service should be targeted at specific crops. [Copyright &y& Elsevier]

Abstract: Due to loss of natural habitats, human-dominated green spaces are likely to increase in importance for biodiversity support. We assessed the potential value of urban “green roofs” for native pollinator conservation in the Chicago region, comparing them with reference habitats of tallgrass prairie natural areas and traditional city-park green spaces. We found that native bees are present on green roofs, though at lower abundance and diversity than in reference habitats. Green-roof and prairie bee communities were distinct from each other, while those in parks were intermediate and similar to the other two habitat types. Bee-community patterns were related to habitat characteristics at both the site and landscape scales. Overall, bee abundance and species richness increased with greater proportions of green space in the surrounding landscape. However, this relationship disappeared in cases where green space was dominated by turf grass. At the site scale, bees benefited from greater plant diversity, and bee and plant-community composition were significantly correlated. Green roofs are potentially valuable sites for bee conservation in urban areas, particularly if planted with diverse native forbs to provide foraging resources, and designed to accommodate bees with different nesting habits. [Copyright &y& Elsevier]

Animal pollination is one of the essential services provided by ecosystems to humans. In the face of a potential worldwide pollination crisis it is important to assess which countries may be more vulnerable in order to prioritize pollinator conservation efforts. The poverty level, the population density and the level of pollinator dependence for food provisioning are key aspects to identify vulnerable countries. We evaluate these aspects and determine the level of human food provisioning dependence on pollinators in Mexico, a developing and highly populated country. The diversity of crop species in Mexico is exceptionally high. Nearly 85% of fruit and/or seed consumed species depend to some degree on pollinators for productivity. Overall, pollinator-dependent crops generate larger income but cover a lower cultivated area and produce less volume compared to non-pollinator-dependent crops. Volume per unit area, however, as well as revenue per unit area, is much higher for pollinator-dependent crops. Native wild pollinators also play a key role in fruit or seed production of Mexican domesticated plant species and in the reproduction of many useful wild species. Thus, assuring free pollination services is particularly important in Mexico as the livelihood of a large proportion of the population exclusively and directly depends on ecosystem services for subsistence. Feasible conservation strategies involve the payment of environmental services to Ejidos (communal land tenure systems) making efforts to protect or restore plant resources and native pollinators, and the creation of new protected natural areas, which ensures food provision, mating and nesting sites for pollinators. [Copyright &y& Elsevier]

Native bees are declining in many regions, often associated with loss of natural habitat. Urbanisation replaces natural vegetation with a highly-modified landscape, where residential gardens are a major component of urban greenspace. While many cities retain native vegetation remnants within the urban matrix, these are often small, isolated and degraded. However, there is little empirical evidence on the capacity of residential gardens to provide equivalent or beneficial habitat for native bees, and which local and landscape factors influence bee assemblages. We surveyed bee assemblages in the southwest Australian biodiversity hotspot at seven residential gardens and seven bushland remnants over two years. We recorded 153 species/morphospecies of native bees. Native bees were more abundant in bushland remnants than residential gardens. Abundance of the introduced honeybee Apis mellifera was generally high, and did not differ between habitats. Bushland remnants hosted more species, and rare and unique species, than did residential gardens. Native bee body-size and nesting guilds varied in their response to habitat type. Native bee abundance and richness increased with abundance of native plant species, but decreased with total flower species richness. Native bee species richness was negatively impacted by urbanisation (built space and isolation from bushland reserves). There were no significant relationships between honeybee abundance and local and landscape factors. Our study demonstrates that while residential gardens can host native bees, urban bushland remnants harbour a more comprehensive suite of species and are key for the conservation of native bee populations. • Urban greenspaces in a biodiversity hotspot support a rich native bee community • Native bee abundance benefits from greater proportions of native flower species • Native bee species richness is associated with greater proportions, yet a lower number, of native flower species • Honeybee abundance is driven by a greater total number of flowers irrespective of origin [ABSTRACT FROM AUTHOR]

[Display omitted] • Topodiversity surrogates may be used for bee conservation planning. • Surrogate spatial grain-size and neighborhood influenced site ranking performance. • Optimal surrogate spatial parameters differed between bees and plants. • Fine-grained topodiversity data improved bee outcomes only. • We advise further study of fine-grained surrogates in other taxa and systems. Biodiversity hotspots are often found in areas of high environmental diversity. This may be explained by an abundance of varying niche space promoting coexistence, buffering effects allowing for persistence during periods of climate change, and by a diversity of selective pressures driving speciation. Thus, environmentally diverse areas are attractive targets for conservation. Few aspects of the environment are unchanging, however, and strategies targeting comparatively durable surrogates for biodiversity are a focus of applied conservation research. For example, topographic diversity (topodiversity), or the variation of landforms present in an area, has proven useful for site prioritization among some taxa. The suitability of this approach for conservation of ecologically important taxa, such as bee pollinators, has not been studied exhaustively, however. Furthermore, the importance of topographic features smaller than 30 m is generally unknown, due to the limited availability of fine-grained elevation data, though could prove relevant for this group and others. We gathered sub-meter elevation data with structure-from-motion photogrammetry and surveyed for bees and plants in the Sapphire Mountains of western Montana, USA to explore if fine-grained topodiversity data are useful for site prioritization. We calculated topodiversity metrics for a range of spatial grain-sizes (0.25–250 m) and neighborhoods (1–500 m) and conducted sensitivity analyses studying correlations with biodiversity patterns. We prioritized sites according to rarity-weighted richness (RWR), which indicates complementarity, or the degree to which a site can contribute unique species to a preserve network. Bee RWR was most strongly correlated with 2 m grain topodiversity data (r 0.73), while plant RWR was most strongly correlated with 235 m data (r 0.44). Though 2 m data were optimal in bees, larger resolutions (35 m) also were effective for site prioritization and use of these meso -grained surrogates only increased site prioritization error by one rank position. We explored multiple regression models predicting RWR with topodiversity metrics of various grains and neighborhood but found no improvement over linear models incorporating only the single most correlated grain-size and neighborhood metric. The best model for plants performed relatively poorly for the task of bee site prioritization. Modeling complementarity with pooled biodiversity data aggregated from both groups slightly improved site rankings for bees and slightly decreased ranking performance in plants. While the costs of fine-grained elevational remote sensing technologies may be high at present, national efforts to gather these data are on the horizon and may facilitate conservation of bees and other groups at the local scale. [ABSTRACT FROM AUTHOR]

Traditional farming landscapes in China consist of small irregular fields with an intimately interspersed semi-natural habitat network of field margins, but are increasingly converted into consolidated ones that consist of standardized fields with reduced areas of field margins and other semi-natural habitat. It is unclear how such farmland consolidation influences pollinator communities, and if there is a negative effect, whether this effect is mitigated by semi-natural habitat present in the wider landscape. We compared the diversity and abundance of wild pollinators in oilseed rape fields that were embedded in landscapes that consisted either of traditional or consolidated farmland. The landscapes spanned a range of semi-natural habitat area from 10% to 73% at a scale of one km radius in Jiangxi Province, China. Pollinators were sampled using pan traps during two years (2015 and 2019). Results showed that pollinator diversity was positively associated with the proportion of semi-natural habitat in both traditional and consolidated farming landscapes, but was higher in traditional farming landscapes. In both years, there was no difference in pollinator abundance between landscapes with traditional and consolidated fields. The results indicate that the network of field margins in traditional farmland supports a diverse pollinator community, and that land consolidation has equivalent effects on pollinator diversity as substantial decreases in semi-natural habitat in the wider landscape. The role of semi-natural habitat in supporting farmland biodiversity and its associated services needs therefore to be considered in plans for farmland consolidation. • China's traditional farmland supports pollinator diversity. • Land consolidation greatly reduces pollinator diversity. • Pollinator diversity was positively associated with the proportion of semi-natural habitat. [ABSTRACT FROM AUTHOR]

• Urban greening may benefit pollinator conservation. • What determines plant-pollinator interactions in urban areas is not well understood. • Phenological overlap was the main mechanism determining interactions. • Simulations indicated that native plants are important for network robustness. • We show how simulations of species removal can be used for urban conservation. Urban green spaces may function as habitats for pollinators. However, it is poorly understood how distinct ecological drivers determine the interactions between pollinator and plants in urban communities, and how pollinator-friendly plants may be selected based on these determinants. Here, we describe an urban hummingbird-plant interaction network in Brazil and evaluate the ecological determinants of pairwise interactions (abundance, morphology, and phenology). Moreover, we used a modeling framework to simulate species removal from networks while allowing for rewiring of interactions, to contrast the importance of native and exotic plants for the network robustness. The studied network showed low specialization and modularity, with one short-billed hummingbird species, Glittering-throated Emerald (Chionomesa fimbriata), dominating the recorded interactions. Phenological overlap was the main determinant of pairwise interaction frequency between hummingbirds and plants. Because morphological matching did not impose strong constraints in the network, simulation models including rewiring based on morphology conferred high robustness after species removal. Furthermore, as exotic plants were only a minor component in the studied network, their removal did not greatly affect network robustness. Our findings demonstrate the importance of considering phenology when planning urban greening for conservation of pollinators. Additionally, we illustrate an analytical procedure that can be applied to quantitatively assess the importance of distinct species/groups for urban interaction networks. [ABSTRACT FROM AUTHOR]

• The public is largely aware of pollinator decline and the major causes. • Most people are already engaged in some form of pollinator conservation. • Insects viewed as pests are considered less important than "charismatic" pollinators. • People in urban areas may feel unsure of how to participate in pollinator conservation. • Engaging with pollinator conservation initiatives may improve pollinator knowledge. Conservation initiatives carried out by informed, enthusiastic participants can be highly effective in conserving biodiversity, including the biodiversity of insect pollinators. It is important to understand how the public perceives insect pollinators, as it may have implications for the success of conservation initiatives and the initiation of protective policies. We used Ireland as a case study to determine how insect pollinators, pollination services, and pollinator decline are currently perceived by the public in an effort to understand the links between public knowledge and perceptions of pollinators, the implementation of insect pollinator conservation actions, and engagement with existing conservation initiatives. We designed a survey that was available to the Irish public for three months, distributed primarily through social media, and was taken by 613 participants. Findings indicate that people are aware of insect pollinator decline and of the main causes and are willing to participate in pollinator conservation, but that there are still some key gaps in the overall understanding of pollinators, their role, and their ecology. Most participants were able to identify charismatic pollinators, such as bumblebees and honeybees, and were aware of their importance to the pollination of crops and wildflowers. Fewer participants were able to identify other common pollinators, such as flies and solitary bees, and many were not aware of the importance of non-bee pollinators to pollination. While engagement with Ireland's national pollinator conservation initiative was linked with increased knowledge of Irish pollinators, less than 50 % of participants, particularly urban dwellers and those without post-secondary education, had heard of the initiative. To ensure a more inclusive approach to insect pollinator conservation, we recommend that future engagement measures highlight the importance of underrepresented non-bee insects to pollination services and target certain demographic groups that are currently not as actively engaged in pollinator conservation as others. [ABSTRACT FROM AUTHOR]

• We conducted a systematic review and meta-analysis of 54 studies. • Field-edge flower plantings consistently increased pollinator richness and abundance in field edges and became more effective as they matured. • The influence of field-edge plantings on crop pollination and yield was inconsistent. • Factors such as landscape context and crop type may influence when plantings are effective. • Defining how plantings impact pollinator population growth would help clarify how they impact on crop pollination and pollinator conservation. Planting flowers along crop field edges is an increasingly common management strategy for addressing pollinator declines and improving crop pollination. However, few reviews have been published summarizing the efficacy of this specific management practice and how it impacts ecosystem service delivery to crops. We conducted a systematic review (54 studies) and meta-analysis (4–29 studies, depending on the response) to determine whether such plantings 1) increase pollinator abundance or richness within field edges, 2) increase the abundance or richness of pollinators visiting crop flowers, or 3) improve crop yields. Our review and meta-analysis suggest that field-edge flower plantings are highly effective at increasing pollinator richness and abundance in field edges and that plantings become more effective as they mature. However, the influence of field-edge plantings on crop pollination and yield is inconsistent. Planting size and richness did not change these results. While this analysis shows that field-edge flower plantings consistently increase pollinator abundance and richness, there remain critical gaps in our knowledge of when and how plantings can improve ecosystem service provision and delivery. Determining if field-edge plantings affect pollinator population growth may clarify how plantings improve crop pollination, while further research on landscape context and crop type may define when this happens. [ABSTRACT FROM AUTHOR]

• Plant growth can be affected by even very low concentrations of non-target agrochemical exposure. • The size of the floral display is a primary driver of insect visitation to flowers. • Insects also change their visitation to plants exposed to agrochemical exposure independently of floral display. • Flower-visiting insects visit herbicide-exposed plants at a significantly lower rate in their first year of growth. • The effects of agrochemical exposure continue into the second year of growth for perennial plants. The increasing extent and intensity of agricultural land use has led to an increase in the volume of agrochemicals applied to the landscape, including those used to improve the nutritional quality of soils (fertilizers) as well as those used to control undesirable species in the agroecosystem (pesticides). Chemicals can disperse in the air and surface and ground water, leading to exposure of non-target organisms. Ruderal, disturbance-tolerant plants on which many flower-visiting insects rely are commonly exposed to these chemicals in agroecosystems. Our research questions were: 1) how does non-target exposure to agrochemicals affect plant growth? 2) what are the indirect effects of non-target exposure to agrochemicals on flower-visitation by insects? We designed a two year field experiment imitating field-realistic fertilizer run-off and non-target herbicide exposure scenarios to explore the impact of low concentrations of fertilizer and herbicide alone, and in combination, on communities of seven plant species, including six native perennials and one non-native annual commonly found in agricultural systems in Ireland (Cirsium vulgare, Epilobium hirsutum, Plantago lanceolata, Origanum vulgare, Filipendula ulmaria, Hypochaeris radicata, Phacelia tanacetifolia). We created field-realistic exposure scenarios by applying concentrations of mineral fertilizer similar to those detected in ground water, and glyphosate levels equivalent to 7.6 % of a standard field application, to the foliage and soil of the plots. We found low concentrations of fertilizer and herbicide affected plant growth: fertilised plants were taller when flowering, while plants exposed to herbicide flowered at shorter heights and produced shorter leaves. The size of the floral display had the largest effect on insect visitation, with larger floral displays significantly more likely to receive a visitor in a given sampling event. The size of the floral display also interacted significantly with the fertilizer treatment for both the abundance and species richness of floral visitors. Overall, our results suggest that there are direct and indirect effects of agrochemical exposure on plants in field margins, and that these effects change the interactions between ruderal plants and flower-visiting insects. [ABSTRACT FROM AUTHOR]

Agricultural intensification is a widespread driver of global pollinator decline that subsequently threatens the associated provisioning of ecosystem services. In North America's Prairie Pothole Region, wetlands surrounded by grassland were once abundant on the landscape, but now generally exist within a matrix of agriculture. We assessed whether restoration of these grassland-wetland complexes from cropland could be used as a potential tool for mitigating wild bee decline, using a 25-year restoration chronosequence. We also monitored the development of bee nesting and food resources to better establish the mechanisms that drive return to a restored habitat. Our objective was to assess whether restoration of grassland-wetland complexes can return bee communities to a reference state (i.e. remnant native grassland-wetland habitats), and to ascertain the timeline over which these changes occur. We found bee diversity increased following restoration and approximated reference sites after 1–4 years, while the diversity of non- Bombus species analyzed separately resembled reference sites after around 5–10 years. Floral diversity also increased following restoration from cropland but remained slightly lower than reference sites through time. Changes to bee species composition were driven more by floral species composition than time since restoration. Our results suggest that restored grassland-wetland complexes are able to provide food and nesting resources to bees within agriculturally dominated landscapes, and that restoration can recover wild bee communities to a reference state. On a broader scale, they underscore the utility of retaining patches of non-cropped and restored land within agroecosystems as a pathway for mitigating pollinator decline. • Bee diversity increased rapidly following restoration to resemble reference sites. • Flower diversity approached reference sites >20 years following restoration. • Abundance of non- Bombus bee species increased with percent bare soil. • Bee species composition was influenced by floral species composition. [ABSTRACT FROM AUTHOR]

Pollinator biodiversity and biomass are in decline globally. This fact accompanied by shortage and collapses of domesticated pollinator colonies, puts human food security under unprecedented threat. Many countries worldwide have adopted or intend to introduce national pollinator conservation strategies. Decisions of policy makers and other involved stakeholders are often driven by pragmatic considerations, rather than biodiversity conservation per se. At the same time, different opinions exist in the literature on the role of pollinator biodiversity versus abundance of few dominant species in crop pollination. This article critically evaluates the literature in order to understand the importance of biodiversity over abundance and to examine the effectiveness of conservation strategies. Results of this review suggest that pollinator biodiversity is critical for crop pollination quality, magnitude and resilience. Most current national pollinator conservation strategies lack comprehensive measures for maintaining pollinator biodiversity at a landscape scale. Unlabelled Image • Discords in the literature lead to different approaches to pollinator conservation. • Biodiversity determines quality, magnitude and resilience of crop pollination. • National pollinator strategies should focus on landscape scale interventions. • Existing strategies often lack focus on landscape complementarity and connectivity. • New policies should take best practices from several different national strategies. [ABSTRACT FROM AUTHOR]

• We predict fairly abrupt thresholds in the relationships between crop pollination service and the amount of surrounding natural vegetation cover. • Pollination service by bees diminished strongly as the proportional natural vegetation cover in surrounding crop fields fell below a threshold. • Our modelling provides a basis for landscape-scale management to prevent pollination-limitation in bee-attractive crops. The conversion of natural vegetation into cultivated land can cause pollinator declines and thereby degrade pollination services to crops and wildflowers. The effect of landscape composition on pollinator abundance is well established, but its impact on pollination intensity and crop yield is not fully resolved. We therefore studied pollination of two crops in India, brinjal (Solanum melongena) and mustard (Brassica nigra), along a landscape-scale gradient in habitat transformation from forest-dominated natural vegetation to intensive cultivation. We quantified the pollination requirements (pollen receipt-seed set relationships) of the crops and the levels of pollen delivery by their principal pollinators, bees. Combining these with field surveys of pollinator abundance, we modelled the levels of pollination service to fields along the landscape gradient. Projected pollination services declined as the area occupied by natural vegetation decreased. We identified thresholds at which bee pollination no longer supported maximum seed set, which were landscapes with approximately one quarter (27 %) of nearby natural vegetation for brinjal fields and one fifth (18 %) for mustard. Our findings indicate that preserving or restoring the cover of natural habitats above these minimum thresholds could be a valuable strategy for maintaining pollinator abundance and safeguarding yield in these bee-pollinated crops. [ABSTRACT FROM AUTHOR]

The expansion and intensification of agriculture are the main causes of current insect declines. Pollinators like cavity-nesting bees can be limited by reduced nesting and feeding opportunities in farmland. As insects constitute the bulk of terrestrial biodiversity and fulfill important ecological functions, there is an urgent need to identify ways to combine agricultural land use and insect conservation. Perennial crops like grapevine can provide permanent habitats for numerous beneficial organisms including various pollinators. With their dominating character in viticultural areas and >7 million ha covered by vines globally, their potential to contribute to nature conservation should be more widely considered. We compared effects of organic management, inter-row vegetation characteristics and landscape parameters on the abundance and species richness of cavity-nesting bees in Central German vineyards. In a paired study design, we assessed cavity-nesting bees in 15 pairs of organically and conventionally managed vineyards along a gradient of landscape complexity. We found that organic management, even though it enhanced flower availability in the vineyards, was only partially beneficial for cavity-nesting bee abundance. Abundance and species richness were enhanced by either semi-natural habitat area or proximity of woody elements like hedges or forest remnants, most likely due to the nesting demands of this particular group of pollinators. We conclude that vineyards can help to sustain cavity-nesting bee abundance, given that landscapes are managed accordingly. We recommend maintaining or establishing woody elements between vineyards, which is likely to also benefit additional groups of organisms such as breeding birds in viticultural landscapes. • Woody elements between vineyards support cavity-nesting bees. • Cavity-nesting bees limited by nesting resources • Habitat area and connectivity promote pollinators in viticulture. • Higher abundance of cavity-nesting bees in organic vineyards [ABSTRACT FROM AUTHOR]