Calcareous grasslands, one of the most species-rich ecosystems in Europe, are threatened by agricultural intensification and land abandonment. To support conservation and maintain ecosystem functioning, it is crucial to understand how arthropod communities respond to local, landscape and regional drivers. We investigated the combined effects of grassland area, management, connectivity, and the area of productive and non-productive agri-environment schemes (AES) in the surrounding landscape on local arthropod biomass, richness, community composition, and trophic guilds across 96 calcareous grasslands in Spain, Germany, and Estonia. Arthropods were sampled using pitfall traps and sweep netting, weighed for biomass, and identified via DNA metabarcoding. Arthropod biomass varied among regions but was unaffected by local or landscape variables, indicating strong regional influence. In contrast, family richness increased with grassland area and the proportion of non-productive AES, highlighting the importance of habitat area and landscape heterogeneity for maintaining arthropod diversity. Community composition differed among regions and was also influenced by grassland area. Among trophic guilds, predators responded mainly to local and regional factors, whereas herbivores, omnivores, and detritivores were also affected by the proportion of non-productive AES in contrasting ways. Overall, arthropod biomass and richness respond independently to environmental gradients, reflecting the combined influence of local, landscape, and regional processes on community structure in calcareous grasslands. Our results underline the importance of conserving large, well-managed calcareous grassland patches while maintaining heterogeneous surrounding landscapes that include non-productive AES to support arthropod diversity across spatial scales.

Emerging infectious diseases (EIDs) threaten biodiversity, yet identifying key host species in complex ecological communities remains a major challenge. Here, we develop a quantitative framework combining field data, epidemiological modelling, simulations, and Bayesian inference to pinpoint key viral hosts in multispecies bee communities. Using flower-visitor interaction data and molecular virus screening, we estimate species-specific basic reproduction numbers (R0) and assess the role of both key hosts and community metrics in virus transmission and persistence. We show that, while honeybees often act as primary reservoirs for deformed wing virus and black queen cell virus, others, such as the bumblebee Bombus lapidarius, can drive the spread of acute bee paralysis virus. Viral dynamics are primarily explained by exposure to key hosts, while community effects are not as pronounced. Identification of non-honeybee key hosts challenges existing assumptions and highlights drivers of transmission and pathogen persistence in complex host-pathogen networks.

Landscape heterogeneity is widely regarded as a key driver of biodiversity, yet it remains unclear whether increasing heterogeneity is always beneficial or whether excessive heterogeneity instead leads to fragmentation. We hypothesized that mixed heterogeneity among land-cover types and within-habitat heterogeneity have distinct effects on biodiversity, potentially explaining contrasting heterogeneity–biodiversity relationships reported across studies. To test this hypothesis, we analysed breeding bird richness from 1,010 1-km² landscapes across Germany together with high-resolution spatial datasets. Mixed heterogeneity was quantified by land-cover diversity and edge density, whereas within-habitat heterogeneity was quantified by tree diversity and edge density in forests and crop diversity and edge density in croplands. We used boosted generalized additive models to assess the effects of different heterogeneity components while accounting for habitat amount and other environmental predictors, complemented by interaction analyses among key predictors. Land-cover diversity consistently increased bird species richness, whereas land-cover edge density showed predominantly hump-shaped relationships, with richness peaking at intermediate levels. The apparent positive effects of land-cover edge density in compositionally simple landscapes largely reflected its strong correlation with land-cover diversity; after accounting for this coupling, its independent effects were negligible or negative. In contrast, within-habitat configurational heterogeneity, represented by tree and crop edge density, was more important for habitat-specialist richness than within-habitat compositional heterogeneity. These positive effects generally weakened or saturated rather than becoming negative with increasing habitat amount. Our results demonstrate that the biodiversity effects of configurational heterogeneity fundamentally differ between mixed and within-habitat heterogeneity. Mixed configurational heterogeneity may ultimately act as fragmentation, whereas greater within-habitat configurational heterogeneity may enhance habitat diversity for specialist birds. Distinguishing mixed from within-habitat heterogeneity and separating compositional from configurational components provides a mechanistic basis for understanding contrasting biodiversity responses to landscape heterogeneity.

Tropical rainforests harbor exceptional biodiversity and function, but are increasingly threatened by agricultural expansion. Whether landscape heterogeneity mitigates these impacts, as in temperate systems, remains unclear. Here, we quantified how local land use and landscape heterogeneity shape multidiversity and ecosystem multifunctionality, using 34 biodiversity metrics and 21 functions across 128 plots in Sumatra. Relative to rainforests, plantations reduced multidiversity and multifunctionality by ~25%, with stronger aboveground declines, lower plant and animal but higher microbial diversity. Contrary to temperate systems, landscape heterogeneity did not buffer local land-use effects but exacerbated declines in multidiversity and multifunctionality, and benefits of surrounding-rainforest cover were confined to rainforest fragments rather than plantations. Our results highlight the irreplaceability of continuous tropical rainforests, and the limited transferability of temperate-based landscape conservation strategies.

The key underlying principle of bioacoustics is the recording of acoustic data and the subsequent identification of taxa from these recordings. Acoustic data can originate from different animal behaviors, such as birdsong, echolocation calls, wing flap, or even crawling on hard surfaces. Typical sound production mechanisms specific to insects include chewing, stridulation in grasshoppers, and the use of tymbals in cicadas, each of which generates distinctive acoustic patterns that can be leveraged for taxon identification. While theoretically a broad diversity of animal taxa can be detected by means of bioacoustic methods, prior research has predominantly focused on birds and bats. Only in recent years there has been much work dedicated to insect sound detection, underpinning the great importance of insects in ecosystems and demonstrating the wider application potential of bioacoustics. Using a methodological survey approach, this paper provides an overview of the current state of the art regarding the use of artificial intelligence and machine learning techniques for acoustic insect recognition. Besides examining data processing methods, we also survey the recording systems that were used to collect insect sounds as well summarizing the characteristics of insect sound datasets used in corresponding studies. Our review revealed that the majority of works focuses on a recognizing particular group of insects only, rather than seeking to identify larger parts of the entomofauna. This is in contrast to recognition approaches for other animals, e.g., birds, where generally all species native to a certain region are considered. Second, real-world insect recordings were only collected in slightly more than half of the surveyed studies, whereas most relied on data from the few datasets published online. Moreover, most studies only recorded acoustic data in controlled environments rather than in the field, thus leaving it unclear whether they will also work in practical settings. Third, in a considerable number of cases, the recording setup used a sampling rate too low to fully capture all sounds produced by insects, leading to the potential omission of important characteristics in the analyses.

Biological pest control is a vital ecosystem service in agriculture, with birds and bats acting as key natural predators of crop pests. However, their relative contributions and how these vary with landscape characteristics remain unclear. We examined the roles of birds and bats in pest control in intensively managed macadamia orchards in South Africa. Using visual and acoustic monitoring, nut quality assessments, and predator exclusion experiments, we examined their influence on insect damage and the effect of landscape characteristics (i.e., cover of natural habitat, altitude, and orchard edges) on predator diversity, composition, and pest control. Excluding birds and bats increased insect damage to nuts from 6.2% to 10.7% (a 70% relative increase). Bat activity reduced damage, with stronger effects in areas with less cover of natural habitat. In contrast, bird abundance did not affect insect damage. Despite these benefits, predator exclusion did not impact yield. Instead, yield followed a unimodal relationship with cover of natural habitat, peaking at 60% and remaining substantially elevated even in landscapes with higher habitat cover. Bird and bat species richness remained high across orchards. Bird community composition varied between orchard edges and centers: forest species were more common at edges, while open-habitat species dominated centers. Bat diversity increased with natural habitat cover but was unaffected by other landscape characteristics. Our findings underscore the importance of natural habitats for biological pest control in agricultural landscapes. By promoting richness and activity of complementary functional predator groups, natural habitats can improve crop quality by indirectly reducing insect damage and thus contribute considerably to agricultural productivity.

Microhabitat-specific responses of soil organisms to land-use intensification remain a major blind spot in biodiversity research. Here, we assessed how protists-key regulators of microbial diversity and nutrient cycling-differ in composition and roles across litter, rhizosphere, and bulk soil along a land-use gradient of increasing management intensity, from rainforest to shrubland, rubber plantations, and oil palm plantations in Sumatra, Indonesia. High-throughput sequencing revealed that rhizosphere protists responded most strongly to land-use intensification, with a 39.6% increase in Shannon index and marked shifts in community composition. Bulk soil protists showed similar but weaker responses, while litter protists exhibited compositional shifts without significant α-diversity changes. Notably, protist community composition was differentially structured by abiotic and biotic drivers across microhabitats independent of land-use type, with biotic dominance in the rhizosphere, abiotic dominance in litter, and joint control in bulk soil. To assess functional turnover, we applied an ecological niche framework (generalist-specialist-opportunist). Generalists remained stable in litter, whereas specialists showed reduced niche breadth and richness in rhizosphere and bulk soil, particularly in oil palm plantations, and opportunists showed intermediate responses. These findings demonstrate that land-use intensification restructures belowground communities in a microhabitat-specific and functionally predictable manner. By explicitly separating litter, rhizosphere, and bulk soil microhabitats, our study reveals microhabitat-specific assembly processes overlooked in conventional bulk-soil analyses and provides new insights into protist responses to land-use intensification in tropical soils. These findings highlight the need to incorporate microhabitat-scale processes when assessing soil biodiversity and ecosystem functioning under environmental change.

Global farmland biodiversity is declining rapidly, threatening both natural ecosystems and agricultural production. Although agri-environmental schemes incentivize farmers to adopt environmentally friendly measures, the spatial mismatch between their local implementation and the landscape-scale habitat requirements of farmland species has been criticized. Landscape-scale agri-environmental schemes (LAESs) are a promising approach for promoting biodiversity effectively through collaboration among multiple farmers. The success of such collaboration for biodiversity conservation relies substantially on well-functioning social networks and economic profitability for participating farmers. For an LAES to be an effective tool, it is crucial to capitalize on potential synergies among social, ecological, and economic benefits arising from collaborative implementation of LAESs and to promote positive feedback loops. We identified six potential synergies originating from the combined benefits of LAESs based on participatory workshops, expert discussions, and scientific evidence, focusing on intensive agricultural systems in Western Europe. Governance structures, such as a coordinating institution, bottom-up approaches, and adaptations to policy frameworks, can promote synergies and help overcome current challenges and trade-offs. The identified synergies and governance structures will be crucial for shaping future European agricultural policies that promote sustainable farmland biodiversity conservation and may serve as a model for transferring LAESs to other global regions.

Developing sustainable agricultural systems requires understanding how landscape composition and agri-environmental measures (AEM) influence natural pest control. Flower fields, implemented as AEMs, can support predatory arthropods, but their landscape-scale effects and how the landscape diversity modulates their effectiveness remain poorly understood. Here we studied interactive effects of landscape diversity and flower field area on predatory arthropods, pests, and pest predation. Using pitfall traps, visual surveys, and aphid cards, we recorded ground- and vegetation-dwelling aphid predators, aphids, and aphid predation. Sampling was carried out across 27 study landscapes in central Germany in 2022 and 2023, before and after establishing 160 ha of flower fields. The landscapes spanned two independent gradients: landscape diversity and landscape-level area of flower fields. Flower field area and landscape diversity interactively affected spider activity, with flower fields being more beneficial in diverse landscapes. Carabid activity was negatively correlated with flower field area, while vegetation-dwelling predators showed no response to landscape diversity or flower field area. Aphid abundance was negatively correlated with carabid activity density. Aphid predation at the vegetation level increased with landscape diversity, whereas ground-level predation was unaffected. Flower fields and predator abundance did not affect aphid predation. Our results indicate that newly established flower fields provide limited support to natural pest control, whereas landscape diversity can provide positive but inconsistent effects. Enhancing natural pest control may require considering landscape composition and successional stage of AEMs rather than establishment of large areas of non-targeted agri-environmental schemes.

Perennial flower fields implemented through agri-environment-climate measures (AECM) are widely used to counteract biodiversity loss. However, little is known about how management factors, such as previous land use and sowing period, as well as landscape context, determine successful establishment of flower fields with few or no agronomically problematic weeds, which can reduce farmers’ acceptance. We recorded the vegetation establishment of 29 flower fields sown with a mixture of native seeds containing 33 species, regionalised for southern Lower Saxony, Germany, over two years. The flower fields, located along a landscape diversity gradient, were sown in autumn or spring and differed in their previous land use (annual crops or AECM fields). From the first to the second year, sown species cover increased by 42.9%, cover of spontaneous species from the seed bank and surroundings decreased by 29.0%. Problematic weed cover was generally low and decreased by 5.0%. Flower fields with previous annual crops had 3.2% less problematic weed cover and 31.4% less spontaneous species cover than flower fields on previous AECM. Sown species cover was higher in previous crop fields in the second year. Only in the first year, autumn sowing increased sown species cover, and spring sowing led to higher problematic weed cover. Sown species established better in low-diversity landscapes, while spontaneous species established better in high-diversity landscapes. Overall, the seed mixture established very well and outcompeted problematic weeds. Flower fields in diverse landscapes also harboured diverse spontaneous species, contributing to the regional species pool. Differences due to management disappeared by the second year. Native seed mixtures with fast growing annual species for weed suppression and regionally adaptable perennial species that establish across a wide range of environmental conditions are highly suitable to create habitats that enhance biodiversity and deliver multiple ecosystem services in agricultural landscapes.

Land-use change is a major driver of bee decline, with solitary and specialist bees being particularly vulnerable due to their nesting and foraging behavior. Understanding how local land use and management practices influence solitary bee resource use is therefore critical for informing conservation in fragmented ecosystems. In this study, we investigated brood cell number and pollen resource use of Osmia leaiana, a solitary bee specializing on Asteraceae, across a network of Estonian calcareous alvar grasslands. We hypothesized that due to the short foraging range of O. leaiana and its dependence on Asteraceae, local management variables such as grazing intensity, shrub cover, and tree cover, affect the taxonomic composition of nest-tube pollen provisions through their effects on local Asteraceae community composition. In addition, we predicted that higher Asteraceae abundance corresponds to greater brood cell production by increasing the availability of preferred resources. Nest blocks were deployed to sites that differed in the composition of the surrounding landscape, management, and plant community composition. Pollen metabarcoding of nest contents was used to assess floral resource use. While Asteraceae abundance did not affect brood cell number, higher proportions of cropland and forest had significant negative effects. Of all assessed variables, proportion of semi-natural grassland within 500 m, tree cover, and the abundance of the subfamily Cichorioideae within grassland patches significantly influenced the composition of pollen provisions. These results indicate that O. leaiana prefers a narrow subset of Asteraceae and primarily forages on plants locally available within semi-natural grasslands, while brood cell production decreased with increasing amounts of alternative land-use types in the surrounding landscape.

Pollination is a key ecological process sustaining biodiversity and food security, yet global patterns of plant–pollinator specialisation have remained unresolved. Using the largest global dataset of quantitative networks (>3,400 networks, >110,000 interactions), we show that the latitudinal specialisation gradient (LSG) exists, but it is non-linear, hemispherically asymmetric, and strongly taxon-dependent. Network-level and pollinator specialisation were lowest in the tropics and peaked at northern mid-latitudes, whereas plants tended to become more specialised toward higher latitudes. Climate consistently outperformed latitude, species richness, and environmental productivity as a predictor of these patterns. Specialisation declined with increasing temperature, rose with moderate rainfall before declining at the wettest sites, and increased with temperature seasonality, but plants and pollinators responded differently to these drivers. Functional groups diverged strongly: ectothermic insects were most specialised in cooler, seasonal climates, while birds showed weaker links to latitude but reduced specialisation in wetter regions. These findings demonstrate that climate, rather than latitude or species richness, structures global variation in specialisation. Because warmer and less seasonal climates promote generalisation, climate change is likely to disrupt the most specialised pollination systems, unevenly across taxa and regions, with important consequences for biodiversity and ecosystem stability. ### Competing Interest Statement The authors have declared no competing interest. Czech Science Foundation, https://ror.org/01pv73b02, 21-24186M, 19-14620S Alexander von Humboldt Foundation, https://ror.org/012kf4317, 1134644 São Paulo Research Foundation, 2023/03083-6, 2023/02881-6, 2023/17728-9 Consulate General of France in São Paulo Bavarian State Ministry of Science and Art Biotechnology and Biological Sciences Research Council Center for Research on Biodiversity Dynamics and Climate Change CEPID-FAPESP, 2021/10639-5 National Council for Scientific and Technological Development, CNPq, 308559/2022-3, 141736/2020-8, 311665/2022-5, 400904/2019-5, 423939/2021-1, 310508/2019-3, 309893/2023-2, 177005/2024-6, 305204/2024-6 CAPES, Finance Code 001; COOPBRASS: 88887.947041/2024-00, 177005/2024-6, PROEX 88882.347259/2019-01 Brazilian Biodiversity Fund, FunBio, 004/2021, 029/2022 Rufford Foundation, https://ror.org/02bxrrf91, 377031, 28478-1 German Research Foundation DFG, 152112243 Dirección General de Investigación, Universidad de San Carlos de Guatemala, 4.8.63.2.27-2012, 4.8.63.8.60-2018, 4.8.63.4.41-2020 FAPEMIG, RED-00039-23 INCT Pollination (CNPq/CAPES/FAPERJ Call 58/2022) Faculty for Future, Schlumberger Foundation the Human Frontier Science Program, RGP023/2023 European Research Council ERC, 101054177, 819374 Knut and Alice Wallenberg Foundation, KAW 2019.0202 LIFE project Olivares Vivos+, LIFE20 NAT/ES/001487 Missouri Department of Conservation, K02442-PI0242-022 National Science Foundation, DGE-2244337 OAPN, 014/2009 CONAHCYT, CBF2023-2024-216 Spanish Ministry of Science, Innovation and Universities, PID2021-127900NB-I00, PGC2018-098498-A-100, RYC2021-032351-I Israel Ministry of Environmental Protection, 121-5-13 German Research Foundation DFG, FZT 118, 202548816

Agricultural landscape simplification due to the loss of semi-natural habitats can act as an environmental filter for species and their functional traits. Both local- and landscape-level factors can shape community structure; although through different mechanisms. In this study, we investigated the role of spontaneous grass field margins in enhancing the taxonomic and functional diversity of ground-active spider assemblages in wheat fields along a landscape diversity gradient. Using pitfall traps, we sampled spiders from 16 wheat fields and three habitat types: the inner field, the field edge and the adjacent grass margin. We collected 2119 spiders (1887 adults) from 72 species and 16 families. Linyphiidae and Lycosidae were the dominant families, comprising 50% and 31% of all sampled individuals, respectively. Landscape diversity had a marginally significant positive effect on functional dispersion, a metric of functional diversity, but did not significantly affect spider activity density or richness. Habitat type had a significant effect on functional diversity but had no effect on activity density and species richness. The spider assemblage in the inner field habitat was less functionally diverse than the assemblages in both the field edge and grass margin habitats. Moreover, grass margins hosted a distinct spider assemblage characterised by larger, free-hunting and less ballooning species compared to the inner field and field edge habitats. Our results suggest that habitat type, and to a lesser extent also landscape diversity, can support more functionally diverse spider assemblages and contribute to shaping the functional structure of ground-active spider assemblages. Particularly, spontaneous grass margins can support large, free-hunting spider species that are absent in wheat fields, potentially enhancing biological control in agricultural landscapes. These results are important for designing agricultural landscapes that promote pest control and for understanding how spider functional traits respond to both local- and landscape-scale factors.Read the free for this article on the Journal blog. Die Vereinfachung der Agrarlandschaft durch den Verlust naturnaher Lebensr & auml;ume kann Arten und ihre funktionalen Merkmale beeinflussen, sowohl auf lokaler als auch auf landschaftlicher Ebene. In dieser Studie untersuchten wir die taxonomische und funktionelle Diversit & auml;t bodenaktiver Spinnengemeinschaften in Weizenfeldern und angrenzenden Grasstreifen entlang eines Landschaftsdiversit & auml;tsgradienten. Mittels Bodenfallen beprobten wir Spinnen in 16 Weizenfeldern und drei Habitattypen: dem Feldinneren, dem Feldrand und den angrenzenden Grasstreifen. Wir erfassten 2119 Spinnenindividuen (1887 Adulte), die 72 Arten und 16 Familien zugeordnet werden konnten. Die dominanten Familien Linyphiidae und Lycosidae machten mit 50% bzw. 31% die gr & ouml;ss ten Anteile der Individuen aus. Der Habitattyp hatte einen signifikanten und die Landschaftsdiversit & auml;t einen tendenziell positiven Effekt auf die funktionelle Diversit & auml;t der Spinnen, aber nicht auf deren Aktivit & auml;tsdichte oder Artenreichtum. Die Spinnengemeinschaften im Feldinneren wiesen eine geringere funktionelle Diversit & auml;t auf als die Gemeinschaften in den Feldr & auml;ndern und Grasstreifen. Au ss erdem beherbergten die Grasstreifen im Vergleich zu dem Feldinneren und Feldr & auml;ndern einzigartige Spinnengemeinschaften, die sich durch gr & ouml;ss ere, frei-jagende und weniger ausbreitungsf & auml;hige Arten auszeichneten. Unsere Ergebnisse zeigen, dass der Habitattyp und in einem geringeren Ma ss auch die Landschaftsdiversit & auml;t die funktionelle Diversit & auml;t bodenaktiver Spinnengemeinschaften beeinflussen. Insbesondere Grasstreifen an Feldr & auml;ndern k & ouml;nnen gro ss e und frei-jagende Spinnenarten f & ouml;rdern, welche nicht im Weizenfeld vorkommen und somit m & ouml;glicherweise die biologische Sch & auml;dlingsbek & auml;mpfung in der Agrarlandschaft erh & ouml;hen. Diese Ergebnisse sind wichtig f & uuml;r die Gestaltung von Agrarlandschaften, die die Sch & auml;dlingsbek & auml;mpfung f & ouml;rdern und erweitern unser Verst & auml;ndnis davon, wie Spinnen mit unterschiedlichen funktionellen Merkmalen auf lokale und landschaftsbezogene Faktoren reagieren.

Agri-environment-climate measures (AECMs) that focus on spatial coordination at the landscape level and the joint working of different actors represent a novel policy approach in Europe. As participation in AECMs generally depends on farmers' motivations and preferences, AECM design needs to consider their perspectives. In this respect, bottom-up collaborative AECMs become increasingly important, as they are driven by actor engagement and interaction. To investigate the factors influencing farmer participation in such approaches and assess their perceived importance, we conducted qualitative in-depth interviews with 36 farmers in northern Germany. At the time of the interviews, the farmers had recently decided whether to participate in a novel bottom-up collaborative AECM initiative. The interviews were analysed using qualitative content analysis. We found that farmers' attitudes towards nature and administrative aspects were most relevant. Economics, farmers' curiosity, and social influences also played important roles. While many of these factors were shaped by past experiences, we identified characteristics specific to collaborative AECMs that influence farmers' decision-making. For example, spatial coordination, farmer-to-farmer communication, expert help or expected conflicts with others were found to have either a positive or negative impact. To increase participation, policymakers and collaborative AECM initiatives should utilise the positively perceived characteristics as levers. For instance, this could involve combining ecologically effective measures with non-monetary benefits, such as support structures and public outreach, as well as providing opportunities for farmers to exchange ideas and share success stories. However, such approaches should also take into account farmers' level of experience with cooperation.

Agri‐environmental and climate measures (AECM) have been designed to promote biodiversity and ecosystem services but have thus far been unable to reverse the strong declines of farmland species. To enhance the environmental effectiveness of and participation in AECM, schemes are increasingly implemented cooperatively at landscape scale. Our study aims at identifying the factors that motivate farmers to participate in cooperative AECM. For this, we conducted a quantitative survey with farmers in Lower Saxony (Germany). We developed a questionnaire that collected data on farmers' participation intentions and experiences with AECM, factors that motivate their participation in AECM, and their perspectives on cooperative AECM. In general, we found that farmers were motivated to participate mainly by economic factors: the financial attractiveness of the scheme and its fit to farming activities. Environmental values and scheme design features were relevant, too. Social factors played the least important role in motivating farmers to engage in AECM. However, specifically for cooperative schemes, social capital was relevant, besides an improved scheme design, an increase in environmental effectiveness, and a reduction of costs and effort. In combination with environmental and economic factors, social motivation gained importance for cooperative AECM. This indicates that when designing cooperative AECM, social factors should not be considered in isolation but in combination with ecological and economic benefits. We derived four policy recommendations from our findings to increase the effectiveness and engagement in cooperative AECM: (1) Offer adequate financial compensation; (2) communicate environmental advances; (3) enhance social interaction and invest in building social relationships; and (4) create cooperative governance structures and cooperation‐oriented scheme design.

To counteract the decline of biodiversity in intensively used agricultural landscapes, a diversity of local conservation interventions, including on-field measures, such as extensification of cereal production, and off-field measures, such as flower strips, is taken. Pollinators, among which wild bees are of particular importance, are a focal group of biodiversity conservation. Although several studies have shown positive local effects of conservation interventions on wild bees, it remains unclear whether these lead to a real increase of wild beess at landscape level. Therefore, we surveyed wild bees in 18 agricultural landscape sections (1 × 1 km) distributed over nine agricultural regions across Germany. In one of the paired landscapes per region, local conservation interventions were implemented, while they were largely absent in the others. We recorded wild bees with a stratified transect sampling on 1000 × 4 m² per landscape where transect sections were distributed proportionally across the edges of all major land-cover types. Further, we conducted GIS-based landscape analyses to calculate the area of conservation interventions and additional landscape metrics, e.g., area of semi natural habitats and edge density. Then, we modelled the effects on landscape-level species richness and abundance of wild bees. Thereby, we also grouped bee species by taxonomy and frequency of occurrence. We found that the area of local conservation interventions was positively related to richness and abundance of solitary bees and rare bees. The abundance of bumble bees and frequent wild bees was positively influenced by crop richness or evenness. In contrast, semi-natural habitats and edge density had no significant effects in the studied landscapes. Our results show that local conservation interventions can promote wild bees at landscape level already few years after their implementation.

Restoring biodiversity in agricultural landscapes requires non-crop habitats that provide complementary and additional resources to those provided by agricultural land. In the European Union, flower strips have become the most popular restoration measure in the last decade, due to their esthetic value, benefits for flower visitors and fast implementation. However, the overreliance on annual flower strips rather than on landscape-wide habitat diversity undermines the agri-environmental goal of a heterogeneous landscape promoting multitaxa biodiversity. Annual flower strips support only a limited spectrum of plant and animal species and we argue that successful biodiversity conservation needs many types of habitats, such as diversified and small-scale croplands in combination with annual, perennial and woody semi-natural terrestrial habitats as well as running and stagnant freshwater bodies. Spatial and temporal habitat heterogeneity and resource continuity allows for spillover across multiple habitat types, meta-community dynamics, high beta diversity and the provision of major ecosystem services such as crop pollination and biological pest control. Implementation of agri-environmental schemes should be more diversified and broadened from the field and farm to the landscape level, based on collaboration of farmers and other stakeholders. We need to foster socio-ecological multifunctionality in biodiversity-friendly agricultural landscapes characterized by diversified and small-scale farming as well as restoration of at least 20 % semi-natural habitat.

To counteract the negative effects of agricultural intensification, several European countries support the use of flower strips or fields as part of agri-environment-climate measures. These habitats provide refuge and food resources for many taxa, including ecosystem service providers. Ground-active predators are important pest control agents. However, comprehensive evidence on how to design these flower areas to maximize their benefits for ground-active predators remains limited. We conducted a meta-analysis of 36 studies spanning the Mediterranean region, Central and Northern Europe to quantify the impact of flower areas on the abundance and species richness of ground-active predators. We also examined whether the overall effects varied in terms of different reference habitats (i.e. semi-natural habitats and crop fields) and regions. Moreover, we identified which characteristics (shape, age and sown plant species richness) contribute to the effectiveness of the flower areas. Flower areas had a moderate positive effect on species richness (Hedges' g = 0.65, 95% CI = 0.22-1.09) and a small positive effect on the abundance of ground-active predators (Hedges' g = 0.21, 95% CI = -0.05-0.48). The effects varied in terms of reference habitats and across regions. Flower areas supported substantially higher species richness compared to crop fields, with an effect size 7.9 times higher than when compared to semi-natural habitats. The positive effect of flower areas on the abundance of ground-active predators in the Mediterranean region was the highest (Hedges' g = 1.03, 95% CI = 0.60-1.45). Among flower area characteristics, linear strips were more effective than large fields in enhancing the species richness of ground-active predators, with an effect size approximately 4.3 times higher. While flower area age and sown plant species richness did not significantly influence either predator abundance or species richness. Synthesis and applications. Our meta-analysis highlights the value of flower areas in supporting ground-active predators, particularly in intensively managed landscapes dominated by crop fields. The strong positive effects observed in the Mediterranean warrant further investigation into underlying mechanisms. We recommend the implementation of flower areas as linear strips, especially in conservation programmes targeting enhancing ground-active predator diversity and associated pest control services.

ABSTRACTLand 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.