Road verges resemble natural bumblebee habitats in terms of flowers and nesting substrates. Hence, they may benefit bumblebee populations, especially in landscape where other floral and nesting resources are scarce. Such benefits may, however, be offset by the adjacency to traffic. As bumblebees move between habitat patches, effects on populations may manifest across landscapes rather than in the local road verge. Using a split-plot design, we studied how wild bumblebees respond to traffic intensity at local and landscape (within 1000 m) scales. We did this along a gradient of open, uncultivated land, including traditionally managed grasslands, which is an important habitat for bumblebees. In 20 study landscapes, we monitored bumblebees along each of three roads, one private road with negligible traffic and two public roads with contrasting traffic intensity (high and low). We assessed mortality, within-season variation in abundance (early queens, early and late workers, and new reproductives), and nest density (supported by scent-trained dogs). Densities of living early queens and workers increased with flower cover in the road verge but decreased with local traffic intensity, which was paralleled by increasing numbers of dead queens and workers. Nests were rare in road verges along the public roads compared to along the private road verges, where traffic was negligible. Despite that traffic clearly increased mortality and restricted the benefit of flowers in road verges, we observed no negative effect of traffic at the landscape-scale. This suggests that other factors are regulating bumblebee populations. We conclude that traffic limits the benefit for bumblebees of flower-enhancement strategies in road verges, but if implemented along roads with low traffic, such actions may be beneficial by promoting forage availability. © 2026 The Authors.

Climate change may affect the yield of mass-flowering crops by altering the interplay between pest pressure and service delivery by pollinators, but realistic predictions need to account for the frequent use of insecticides in conventional farming. We tested the interactive effects of insecticide use and warmer winter conditions on oilseed rape (Brassica napus) production, pest pressure, and the activity of Bombus terrestris, an important bumblebee pollinator. We evaluated the effects of three different insecticides at two different concentrations. We found that winter warming reduced the effectiveness of two insecticides against pollen beetles in comparison to the control (no insecticides), likely due to the dilution of insecticides on plants with increased plant size. Additionally, plots treated with reduced concentrations of insecticides generally had similar levels of pollen beetles as those with standard concentrations. There were no interactive effects of insecticide application and winter warming on pollinator activity or oilseed rape yield. However, yield quality was negatively affected by winter warming. Under current winter conditions, reduced insecticide applications may provide pest control comparable to standard applications and could therefore serve as an integrated pest management strategy. Under future winter conditions, such strategies will likely need to consider the effects of climate change on plant development, because the overall effectiveness of insecticide treatment against pests could decrease. © 2025 The Authors

Road verges can provide resources for pollinating insects, but it remains unclear if these resources are accessible to all species, or if some ecological traits can prevent certain species from using road verge habitats. We sampled wild bees and butterflies in 37 road verges in southern Sweden, with contrasting mowing regimes and along a gradient of traffic intensity. We compiled data on the pools of the regionally occurring species of wild bees and butterflies, and on ecological traits related to body size, feeding specialization and nesting habitat or overwintering stage. First, we tested if any of the selected ecological traits explained why some species were absent from road verges. Among the species that occurred in road verges, we then tested how the ecological traits influenced their response to management regime, verge width and traffic intensity. Along 7400 m of road verges, we observed 39% of bee species and 43% of the regionally occurring bee and butterfly species. Cavity-nesting bees were more likely to be absent from road verges than soil-nesting bees, but none of the ecological traits explained which of the regionally occurring butterfly species were absent from road verges. Among solitary bee and butterfly species that occurred in road verges, wider road verges reduced the absence probability more in dietary specialists than in generalist species. In bumblebees, wider road verges reduced the absence probability more in small-bodied than in large-bodied species. Our results indicate that road verges are suitable habitats for many but by far not all bee and butterfly species, and that certain species are prevented from using road verges because of their ecological traits. This needs to be considered when road verges are designed or managed to promote biodiversity. © 2026 The Author(s).

Road verges can harbour a diversity of flowering plants and may be useful foraging habitats for pollinating insects in landscapes where flower-rich habitats are scarce. Targeted management of road verges can further enhance flower abundance, thereby potentially benefitting flower-visiting insects. However, traffic on the adjacent road could pose a risk, such that flower-rich road verges instead act as ecological traps, attracting flower-visiting insects to a hazardous environment. To investigate the suitability of road verges for the implementation of pollinator promoting actions, it is important to understand the risks associated with these habitats. By placing three commercial bumblebee colonies with individually tagged workers at each of 12 road verges, we studied whether traffic intensity influenced individual worker mortality, worker behaviour, and colony growth. We visited the colonies weekly to determine how frequently workers leaving the nest headed towards the nearest road verge and, when crossing the road, at what height they did so. Only 10 % of the departing workers were observed to cross the road and 65 % of these crossings occurred higher than 1.5 m, corresponding to the height of an average passenger car. The proportion of bees heading towards the nearest road verge when leaving the nest declined with traffic intensity. About 22 % headed towards road verge at 100 vehicles/24 h, whereas only 7 % departed in this direction at 20,000 vehicles/day. We suggest that the bumblebees avoided foraging in road verges with disturbing turbulence from passing vehicles, potentially protecting them from traffic-related mortality. Indeed, we found no evidence for traffic to influence individual worker mortality or colony weight change. We conclude that traffic does not pose a severe threat to bumblebee workers, as they avoid flying towards the road. The benefit of adapted management may therefore be limited by traffic and should be targeted to roads with low traffic. © 2025 The Authors

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. © 2024 The Authors.

Land use change threatens global biodiversity and compromises ecosystem functions, including pollination and food production. Reduced taxonomic α-diversity is often reported under land use change, yet the impacts could be different at larger spatial scales (i.e., γ-diversity), either due to reduced β-diversity amplifying diversity loss or increased β-diversity dampening diversity loss. Additionally, studies often focus on taxonomic diversity, while other important biodiversity components, including phylogenetic diversity, can exhibit differential responses. Here, we evaluated how agricultural and urban land use alters the taxonomic and phylogenetic α-, β-, and γ-diversity of an important pollinator taxon-bees. Using a multicontinental dataset of 3117 bee assemblages from 157 studies, we found that taxonomic α-diversity was reduced by 16%-18% in both agricultural and urban habitats relative to natural habitats. Phylogenetic α-diversity was decreased by 11%-12% in agricultural and urban habitats. Compared with natural habitats, taxonomic and phylogenetic β-diversity increased by 11% and 6% in urban habitats, respectively, but exhibited no systematic change in agricultural habitats. We detected a 22% decline in taxonomic γ-diversity and a 17% decline in phylogenetic γ-diversity in agricultural habitats, but γ-diversity of urban habitats was not significantly different from natural habitats. These findings highlight the threat of agricultural expansions to large-scale bee diversity due to systematic γ-diversity decline. In addition, while both urbanization and agriculture lead to consistent declines in α-diversity, their impacts on β- or γ-diversity vary, highlighting the need to study the effects of land use change at multiple scales. © 2025 John Wiley & Sons Ltd.

Recent studies have demonstrated that the pace of global biodiversity decline is increasing despite the rising evidence that biodiversity underpins crucial ecosystem services essential for human wellbeing. A major reason for this antagonism is that people’s claim to have a strong interest for biodiversity is resulting in numerous beneficial actions by groups, whereas societal norms may lead to counteractive behaviour of individuals. Therefore, we argue that awareness and evidence on the importance of biodiversity do not necessarily increase protection of it. In an ongoing crossdisciplinary research program (https://www.hh.se/forskning/forskningsprogram/trains---transformation-innovation-ochnormstudier.html), our aim is to extend research on the concept of norms to include expectations embedded within and across different systems of actions: natural/biotic, economic/technical, legal/bureaucratic, and cultural. Here we will discuss different perspectives on how production goals may counteract biodiversity goals, where large-scale changes to policies are needed to achieve the global goals. In addition to large-scale measures, we will have a specific focus on when social norms are leading to individuals contributing to protection of biodiversity and when not, based on conflicts where costs and/or risks for the individual are involved. This will be illustrated by experience from pedagogy of a bachelor’s program in nature conservation and biodiversity.

Aim: Aquatic-terrestrial transition zones contain features essential for many species that often benefit wetland biodiversity. Shallow flood-zone areas and reed beds are indicative of natural wetland habitats; however, how such features affect the native arthropod biodiversity in constructed wetlands is scarcely investigated. We asked how these shoreline features, as well as wetland shoreline properties and grazing management, influence riparian arthropod diversities and habitat specializations.

Location Constructed wetlands, Sweden.

Taxa Araneae, Coleoptera, Diptera.

Methods: Taxonomic-, phylogenetic- and trait diversities, along with habitat specialist species richness, were measured in riparian spiders, beetles and selected Diptera in 68 constructed wetlands in two regions of Sweden. We ran structural equation models to estimate direct and indirect effects from shoreline slope, flooded grassland, reed areas and grazing management on group diversities, and used multivariate models to determine drivers on habitat specialist species richness.

Results: Flooded grassland and reed area, along with shoreline slope influenced arthropod diversities, and responses differed between arthropod groups and diversity metrics. Spider trait diversity was greater in wetlands with larger flooded grassland areas, whilst beetle trait diversity was reduced. Spider phylogenetic diversity was greater in wetlands containing larger reed areas and in wetlands with steeper shorelines. However, species richness in predatory flies was greater in wetlands with more gentle shorelines. Grazing management had limited effects on arthropod diversities; however, species richness in wetland specialist and generalist predatory dipterans was greater in the absence of grazers in wetlands with greater flooded grassland areas.

Main Conclusions: As requirements vary considerably among arthropods, care must be taken when constructing and managing wetlands to benefit arthropod biodiversity. The present results suggest wetlands with a varied shoreline, albeit with greater proportions of flood areas, or multiple adjacent wetlands with varying shores in a wet landscape and a mild grazing regiment, would accommodate a more diverse arthropod fauna. © 2024 The Author(s). Journal of Biogeography published by John Wiley & Sons Ltd.

Wetland hydrological dynamics often dictate the composition of biological communities found in or near wetlands, either directly or through changes in vegetation composition. However, much remains unknown, particularly regarding how riparian arthropods respond to such dynamics. In this study, we used high-resolution hydrological data, along with presence of grazing livestock and shoreline vegetation height from 41 constructed wetlands in south-western Sweden to explore flood zone areas, flood frequencies, vegetation and grazing as drivers of the resident arthropod communities. The collected material consisted of 26,817 arthropods, where the dominant groups were Diptera (13,258 specimens), spiders (6,207) and Coleoptera (2,858), which were collected using SLAM (Sea Land and Air Malaise) trapping, along with pitfall trapping and vacuum sampling of riparian arthropods. We found group-specific responses to inundation frequencies, where wetlands with higher frequencies had lower abundances of some beetles and tipulids, and where wetlands with longer low-water table periods contained less trichopterans and heteropterans. In contrast, the size of flood zone areas only affected some wolf spider groups, that were more abundant in wetlands with intermediately sized flood zones. Shoreline vegetation height affected multiple groups, spiders, beetles and dipterans, but in different directions, whereas presence of grazing livestock had limited impact on abundances and community compositions. Given the variable responses to wetland hydrological and structural drivers, it seems that wetland arthropod communities would benefit from a high local wetland habitat variability, or wetlandscapes where individual wetlands have differing hydrological dynamics, morphology and vegetation. © 2024 The Authors.

Pollinerande insekter är viktiga för vår matproduktion eftersom de gynnar skördarna i 75% av de odlade grödorna, exempelvis många frukter och olje- och proteingrödor. Andra organismer, så kallade skadegörare, påverkar istället skördarna negativt, genom konkurrens, herbivori eller smittspridning. Dit hör bland annat ogräs och skadedjur. För att kontrollera skadegörare används olika former av växtskyddsmedel, det vill säga kemiska eller mikrobiologiska preparat, vars syfte är att skydda grödorna och därmed säkra produktionen. Dessa växtskyddsmedel påverkar dock inte bara målorganismerna och de utgör därför även en risk för pollinatörerna och deras viktiga pollineringstjänster inom odlingen. Den här kunskapssammanställningen är framtagen på uppdrag av Växtskyddsrådet och är en av flera planerade insatser som syftar att bidra till att öka kunskapsläget kring hur växtskyddsmedel påverkar pollinatörer i odlingslandskapet, samt vilka åtgärder som kan vidtas för att främja och skydda pollinatörer vid samtidig användning av växtskyddsmedel.

Pollinatörsgrupperna som är i fokus i den här rapporten är bin (honungsbin, humlor och solitärbin), fjärilar och blomflugor. Växtskyddsmedel kan påverka olika pollinatörsgrupper på olika sätt. Detta beror delvis på att deras exponering för växtskyddsmedel varierar, vilket är kopplat till de egenskaper som styr pollinatörernas aktivitet i tid och rum. Aktivitetsperiod, rörelsemönster, födopreferenser, typ av boplats och grad av socialitet har pekats ut som potentiellt viktiga egenskaper för att bedöma exponering. Denna kunskapssammanställning, som främst baseras på tidigare litteratursammanställningar, visar dock att kunskapsluckorna är för omfattande för att generella slutsatser ska kunna dras om vilka egenskaper som är att förknippa med hög exponering, risk och påverkan av växtskyddsmedelsanvändning.

Påverkan kan vidare ske genom både direkta och indirekta effekter. Direkta effekter uppstår genom exponering och upptag av toxiska ämnen som påverkar pollinatörers överlevnad, beteende eller reproduktion. Indirekta effekter uppstår via interaktion med andra organismer som exponeras och påverkas, med effekter såsom förändrad födotillgång eller konkurrens. För speciellt insekticider är direkta effekter relativt väl studerade jämfört med indirekta effekter, även om en övervägande del av studierna genomförts under kontrollerade laboratorieförhållanden och därmed är svåra att direkt översätta till effekter i verkliga jordbrukslandskap. Antalet studier skiljer sig även stort mellan pollinatörsgrupper, där bin, och särskilt honungsbin, är den mest välstuderade gruppen medan det finns betydligt färre studier av effekter på fjärilar och blomflugor.

Vi kan med god sannolikhet konstatera att exponering och potential för direkta effekter är extra hög under maj och juni när flera pollinatörsgruppers höga aktivitetsnivå sammanfaller med användningen av särskilt toxiska växtskyddsmedel (insekticider). Vidare visar ett antal studier på att honungsbiet samlar pollen som innehåller högre halter av växtskyddsmedel och med sammanlagd högre toxicitet jämfört med andra biarter. Detta är sannolikt kopplat till honungsbinas opportunistiska och generella födosöksbeteende som medför en attraktion till massblommande grödor och andra blomresurser i eller intill grödor som kan vara växtskyddsmedelsbehandlade.

För att kunna spåra växtskyddsmedelsexponering och effekter på pollinatörer, effektivitet hos åtgärder som införs för att minska växtskyddsmedelsrisker och för att följa relevant miljömålsuppfyllelse behövs någon form av miljöövervakning med avseende på växtskyddsmedel för pollinatörsrelevanta förhållanden. Ett sådant alternativ är riskindex som bygger på summerade toxicitetsviktade halter av växtskyddsmedel i miljöer och material som är relevanta för organismgruppen. Riskindex av den typen har länge använts för vattenlevande organismer. Nyliga studier tyder på goda möjligheter för att använda liknande principer genom att kombinera halter av växtskyddsmedel i pollen insamlat av honungsbin med information om växtskyddsmedlens bitoxicitet. Denna metod för att skatta växtskyddsmedelsrisk för bin verkar vara konservativ, dvs ge en viss överskattning av risken för bin andra bin än honungsbiet, och vara landskapsoberoende genom att risken för andra bin sannolikt överskattas i landskap med mer halvnaturliga miljöer. Dessa är viktiga egenskaper hos ett riskindex för pollinatörer eftersom det beaktar både försiktighetsprinciper och tillämpbarhet under verkliga förhållanden.

Trots fortsatt stora kunskapsluckor gällande exponering, risker och effekter av växtskyddsmedel på pollinatörer, finns det en del studier gällande vilka åtgärder som skulle kunna tas för att minska spridning till miljön. Exempelvis kan man som ett första steg applicera minsta tillräckliga dos, och anpassa tidpunkten för denna applicering så att överlappet med pollinatörernas aktivitetsperiod minimeras. Vidare kan sprutfria buffert- eller kantzoner anläggas i eller utanför fältet för att fånga upp och därmed minska spridning av växtskyddsmedel till omgivningarna. Sådana buffert-/kantzoner skulle kunna innehålla blommande födoresurser för pollinatörerna, som, även om de innehåller växtskyddsmedelsrester, kan bidra med en nettonytta för pollinatörerna. På liknande sätt kan buffrande effekter uppnås i ett större landskapsperspektiv genom att öka andelen halvnaturliga habitat med alternativa och obesprutade födoresurser. En ökad andel halvnaturliga habitat kan även bidra till en snabbare återhämtning av populationer som gått förlorade lokalt på grund av växtskyddsmedelsanvändning. Det behövs dock studier för att klargöra om så är fallet även under svenska förhållanden. Välgrundad användning av växtskyddsmedel, lokala buffert-/kantzoner och mängden halvnaturliga miljöer i landskapet kan ingå som delar i integrerat växtskydd (IPM; integrated pest management) där hänsyn tas till behov av pollinatörer i produktionen liksom pollinatörshälsa (IPPM; integrated pest and pollinator management). IPPM som bygger på kunskap om vad som gynnar pollinatörer och hur växtskyddsmedelsanvändning kan påverka pollinatörer skulle därför kunna vara ett samlande konceptet för att arbeta vidare med att skydda och gynna pollinatörer under fortsatt användning av växtskyddsmedel.