Field Interiors Research Articles

Plant species richness in intensively managed temperate wet grasslands: current state and the importance of edge habitats

This study investigates within-site variation in the diversity and composition of aboveground vegetation and seed bank in intensively managed wet grasslands of north-western Germany, comparing field edges, field margins and field interiors. We tested the hypothesis that unfertilized buffer strips at field edges function as refugia of characteristic species even in grasslands that are managed intensively for silage production. In 55 grassland sites on each marsh and moor soils, respectively, we conducted vegetation surveys, seed bank analyses and soil chemical measurements in field edge, margin and interior plots, and searched for the factors causing within-site variation in vegetation composition. The total species pool was small at the 110 sites, i.e. 148 species in the aboveground vegetation and 107 species in the seed bank, demonstrating severe impoverishment. The α-diversity decreased from 23 species (median) per 200 m2 at the edge to 15 species in the interior, with 38 species occurring only at field edges. The number of species with conservation value was very low in aboveground vegetation and seed bank and was only slightly higher at the edge than in the interior. Soil P availability was ca. 30% lower at the unfertilized edges than in the interior. We conclude that unfertilized buffer strips at grassland edges may help reducing nutrient leaching from high-input grassland systems, but they have mostly lost their refugial function for phytodiversity after decades of intensive management. Restoration efforts with seed or green hay transfer from richer source habitats are needed to promote biodiversity in field-edge buffer strips.

Plant species richness increase across crop field–dry grassland edges masks diverging patterns in generalists and specialists

ContextThere is an urgent need to stop the biodiversity loss in European agricultural landscapes. These landscapes, due to their fragmentation, include a lot of edges, many of them between habitats of different quality in terms of biodiversity. ObjectivesHere, we ask how plant species richness is distributed from the interior of protected semi-natural grassland into the interior of adjacent crop fields, and which species groups determine the observed patterns.MethodsAt grassland–crop field interfaces in two German landscapes, we sampled the vegetation along transects extending 32 m into both habitats. Based on theory, we fitted different models to visualize the species richness curve along transects and selected the best model via AIC. ResultsThe best fitting model for all species was monotone over the interface with a minimum in the field and a maximum in the grassland. This shape was driven by the generalists, showing the same pattern, while grassland specialists showed a sigmoid curve with an increase only in the grassland. Arable specialists had a peak at the field edge and decreased towards the grassland. Curves for Ellenberg indicator values for moisture, nutrients and light showed the same shape as the overall species curve, yet with an inverse pattern for light. ConclusionsThis is the first study revealing gradual responses of plant species richness at the grassland–crop field interface with a high spatial resolution. As these adjacent habitats influence each other far into their neighbourhood, attention should be given when conserving biodiversity in agricultural landscapes, particularly in case of often small and scattered protected areas.

Distance functions of carabids in crop fields depend on functional traits, crop type and adjacent habitat: a synthesis.

Natural pest and weed regulation are essential for agricultural production, but the spatial distribution of natural enemies within crop fields and its drivers are mostly unknown. Using 28 datasets comprising 1204 study sites across eight Western and Central European countries, we performed a quantitative synthesis of carabid richness, activity densities and functional traits in relation to field edges (i.e. distance functions). We show that distance functions of carabids strongly depend on carabid functional traits, crop type and, to a lesser extent, adjacent non-crop habitats. Richness of both carnivores and granivores, and activity densities of small and granivorous species decreased towards field interiors, whereas the densities of large species increased. We found strong distance decays in maize and vegetables whereas richness and densities remained more stable in cereals, oilseed crops and legumes. We conclude that carabid assemblages in agricultural landscapes are driven by the complex interplay of crop types, adjacent non-crop habitats and further landscape parameters with great potential for targeted agroecological management. In particular, our synthesis indicates that a higher edge-interior ratio can counter the distance decay of carabid richness per field and thus likely benefits natural pest and weed regulation, hence contributing to agricultural sustainability.

Combination of organic farming and flower strips in agricultural landscapes – A feasible method to maximise functional diversity of plant traits related to pollination

Agri-environment schemes (AES) are valuable instruments to support pollination in agricultural landscapes. Evaluating AES based on their effects on pollinators has high practical relevance for agricultural production and nature conservation. In our two-year assessment, we studied the effectiveness of two AES (organic farming vs flower strips) on plant traits associated with pollinator attraction (flower size, colour, and ultraviolet pattern) and reward accessibility (flowering duration, and nectar quantity). We selected ten landscapes along a landscape-scale field size gradient in Central Germany. Three types of winter wheat fields (organic, and conventional fields with and without flower strips) were chosen in each landscape. We sampled the vegetation in transects designated in characteristic field parts, i.e. grassy margins, field edges (or flower strips), and field interiors in the growing seasons of 2016 and 2017. We calculated community-weighted means and functional diversity of plant traits and tested the effects of field size, management, and within-field position with linear mixed-effects models. We showed that organic fields and flower strips provided more abundant and functionally more diverse flowers than conventional fields. Flower strips were superior with the highest insect-pollinated plant cover and the highest ratio of plants with flowers showing ultraviolet patterns. Although grassy margins next to flower strips harboured twice as many species as those without flower strips, this positive effect did not emerge in conventional field interiors. Landscape configuration expressed as mean field size did not affect pollination traits in our study. Our results highlighted that both organic farming and flower strips maintained abundant and functionally diverse insect-pollinated flora, and thus they can potentially support larger pollinator communities. However, only organic farming could maintain high functional diversity of pollination-related plant traits in field interiors. Hence flower strips and organic farming in combination might be a good option for sustaining diverse pollinator communities and their services. • Organic fields and annual wildflower strips can boost pollinator-friendly flora. • Plant pollination trait diversity is high in both agro-environmental schemes. • Both schemes can supposedly maintain high pollination ecosystem service. • There is little spill-over from flower strips to intensive field interiors. • Plant functional diversity of grassy field margins benefited from flower strips.

Configurational landscape heterogeneity: Crop-fallow boundaries enhance the taxonomic diversity of carabid beetles and spiders

Arthropod biodiversity in agricultural landscapes is favoured by high levels of compositional and configurational heterogeneity. In terms of composition, the high value of non-crop habitats is firmly established. In contrast, the causes underlying positive effects of configurational heterogeneity, i.e. patch size and boundary length, are less well understood. We here test the hypothesis that boundaries comprise valuable habitats in its own right by enhancing the taxonomic diversity of carabid beetles and spiders. We used pitfall traps placed along transects running from the interior of wheat fields across the habitat boundary to the interior of unmanaged grassland fallows. Taxonomic diversity was highest around the boundaries due to (1) spillover effects but also (2) species showing a distinct preference for edge habitat. For carabids, habitat boundaries harboured distinct species assemblages. Grassland fallows had, especially in spiders, positive effects on the taxonomic diversity of crop fields close to the boundary, while no negative effects of crop fields on adjacent fallows could be found. Overall, taxonomic diversity was higher in grassland fallows than in crop fields, though differences were surprisingly small. The high taxonomic diversity found for boundaries suggest that these may comprise valuable habitats in its own rights, which in turn may causally underpin positive effects of configurational heterogeneity on arthropod diversity in agroecosystems. Thus, increasing configurational heterogeneity, e.g. by promoting small field sizes and high edge density, seems an important tool for preserving farmland biodiversity.

Derivation of the Symmetric Stress-Energy-Momentum Tensor in Exterior Algebra

We present a derivation of a manifestly symmetric form of the stress-energy-momentum using the mathematical tools of exterior algebra and exterior calculus, bypassing the standard symmetrizations of the canonical tensor. In a generalized flat space-time with arbitrary time and space dimensions, the tensor is found by evaluating the invariance of the action to infinitesimal space-time translations, using Lagrangian densities that are linear combinations of dot products of multivector fields. An interesting coordinate-free expression is provided for the divergence of the tensor, in terms of the interior and exterior derivatives of the multivector fields that form the Lagrangian density. A generalized Leibniz rule, applied to the variation of action, allows to obtain a conservation law for the derived stress-energy-momentum tensor. We finally show an application to the generalized theory of electromagnetism.

Current State and Drivers of Arable Plant Diversity in Conventionally Managed Farmland in Northwest Germany

Agricultural intensification has led to dramatic diversity losses and impoverishment of the arable vegetation in much of Europe. We analyzed the status of farmland phytodiversity and its determinants in 2016 in northwest Germany by surveying 200 conventionally managed fields cultivated with seven crops. The study was combined with an analysis of edaphic (soil yield potential), agronomic (crop cover, fertilizer and herbicide use) and landscape factors (adjacent habitats). In total, we recorded 150 non-crop plant species, many of them nitrophilous generalist species, while species of conservation value were almost completely absent. According to a post-hoc pairwise comparison of the mixed model results, the cultivation of rapeseed positively influenced non-crop plant species richness as compared to winter cereals (wheat, barley, rye and triticale; data pooled), maize or potato. The presence of grassy strips and ditch margins adjacent to fields increased plant richness at field edges presumably through spillover effects. In the field interiors, median values of non-crop plant richness and cover were only 2 species and 0.5% cover across all crops, and at the field edges 11 species and 4% cover. Agricultural intensification has wiped out non-crop plant life nearly completely from conventionally managed farmland, except for a narrow, floristically impoverished field edge strip.

Reduced overwinter survival of unharvested corn in fields with cover crops

AbstractVolunteer corn arising from unharvested kernels in fields is a common problem that reduces yield of crops like soybean in intensive rotational agricultural systems. Over the last decade, farmers in the Midwestern United States have increased use of cover crops to improve soil health and suppress weeds in corn‐soybean rotational agriculture. We assessed whether the fate of unharvested corn kernels in cover‐cropped fields differed from fields without cover crops. After the 2018 harvest season, we recorded overwinter removal and spring 2019 germination of corn kernels from plots in six fields in Tippecanoe county, west‐central Indiana, United States. We used mixed effects logistic regression to model the role of a cereal rye cover crop, bare ground, soil drainage class, distance from field edge, and average height of vegetation on mortality of kernels. Probability of kernel absence from a plot was greater in fields planted to cover crops (0.93–0.98) than in no‐till fields without cover crops (0.53–0.85). Distance from field edge was positively related to kernel loss in cover‐cropped fields, but negatively related to loss in fields without cover crops. Within cover‐cropped fields, kernel removal near field edges increased to levels comparable to field interiors only for plots with >15% bare ground. Cover crops substantially reduced survival of corn kernels that serve as prospective volunteer corn, consistent with increased foraging activity and use of cover‐cropped fields by vertebrate seed predators.

Habitat Associations of Bats in an Agricultural Landscape: Linear Features Versus Open Habitats.

Simple SummaryUnderstanding how species interact with agricultural landscapes is essential for future conservation efforts. Using a large-scale citizen science project, we examined the influence linear features have on bat activity compared to the centre of agricultural fields and detailed the effect of different types of linear features (intensively managed hedgerows, sympathetically managed hedgerows and treelines). Our results showed that all 10 bat species groups identified during surveys occurred both in the centre of fields as well as along linear features. Out of the five species groups analysed further, only Nyctalus noctula had no preference for linear features, compared to the centre of agricultural fields; however, 29% of Rhinolophus ferrumequinum calls were recorded in the centre of fields. More species were active near treelines compared to other linear feature types. Our results highlight the importance of linear feature management to bat conservation, but also the need to consider field centres during survey design and Environmental Impact Assessments1. Bats are important components of agricultural ecosystems. However, little is known about the extent to which bats use linear features when foraging and commuting in agricultural settings, when compared to the interior of fields. 2. As part of a large-scale citizen science project, bat detectors were placed in the centre of agricultural fields (arable and pasture) and along linear features (intensively managed hedgerows, sympathetically managed hedgerows and treelines). 3. Our results show that all 10 of the bat species groups identified were found both along linear features and in the middle of agricultural fields. Of the five species groups analysed further, all had significantly more bat activity along linear features compared to the middle of fields, except for Nyctalus noctula. However, our results showed that 29% of calls from Rhinolophus ferrumequinum were recorded in the middle of agricultural fields, compared to only 10% for Pipistrellus pipistrellus. Bat activity was more likely to be associated with treelines compared to other linear feature types. 4. Our results highlight the importance of linear feature management to bat conservation, but also the need to consider field centres during survey design and Environmental Impact Assessments.

Field margin floral enhancements increase pollinator diversity at the field edge but show no consistent spillover into the crop field: a meta‐analysis

Abstract Conventional intensification of agriculture has reduced the availability of resources for pollinators, reducing their diversity and affecting plant pollination, both in natural habitats and croplands. Field margin floral enhancements such as flower strips or restored field margins could counteract these negative effects. The approaches to assess the success of these management measures generally evaluate separately the pollinator response at the edge and within the crop, as proxies for pollinator conservation and pollination services, respectively. We performed a meta‐analysis to understand the influence of field margin floral enhancements on the abundance and richness of pollinators at the edge and within the field, and on crop yield. We estimated 137 effect sizes from 40 studies, all from the northern hemisphere. Overall, the field margin floral enhancements increased the abundance and richness of pollinators at the field edge but had no consistent effect in the interior of the crop fields. Few studies evaluated crop yield, and in these studies no effects were observed. These results suggest that field margin floral enhancements can constitute a positive conservation action for pollinators but not necessarily associated with pollination ecosystem service.

Arthropod functional traits shaped by landscape-scale field size, local agri-environment schemes and edge effects

Agri-environment scheme (AES) approaches can be classified according to whether they prescribe management in non-productive areas, such as field boundaries and wildflower strips, or in productive areas, such as arable crops. Here we tested the ecological effectiveness of two popular AESs in Germany: wildflower strips next to winter wheat fields as off-field management and organic farming on winter wheat fields as on-field management. We selected ten landscapes along a field size gradient with three focal wheat fields, one conventional field with flower strip, one organic field and one conventional field without flower strip as a control. We sampled arthropods with pitfall traps at field edges and field interiors. We selected three ecological traits for spiders and carabids (body size, feeding trait, dispersal ability). We calculated community weighted mean values (CWM), and we used linear mixed effects models to test the effect of management type and transect position on CWM values. We found pronounced edge effects on most traits, and weaker effects of field size and AES in shaping functional traits. Smaller spiders, spiders with higher ballooning propensity and more web-builders were in the field interior than at the field edge, whereas carnivore carabids preferred field interiors. We also found a strong effect of landscape configuration, i.e. mean field size, as larger field size was positively related to more web-building spiders and more carnivore beetles. Flower strips enhanced populations of web-building spiders. Our results suggest that small-scale agriculture leading to high landscape-scale edge density has a major effect in shaping functional traits and potential ecosystems services in agricultural landscapes. Spider and carabid communities exhibit very different responses to edge vs. interior sites, and, based on the landscape-scale field size gradient emphasize the importance of landscape configuration in shaping the heterogeneity of the arthropods’ traits and presumably ecosystem services in agricultural landscapes.

Distribution of ecosystem services within oilseed rape fields: Effects of field defects on pest and weed seed predation rates

Frequent extreme weather events, which jeopardize agriculture by affecting crop health, characterize the ongoing climate change. Temporary patches where sown plants are poorly developed (hereafter “field defects”) are likely to increase with climate change and can be colonized by other plant species. Although perennial non-crop habitats can act as refuges for beneficial insects in agricultural landscapes and increase ecosystem services (ESs) in neighbouring arable fields, the relevance of field defects is unknown. Here, we quantified two ESs (pest and weed seed predation) in field defects within oilseed rape crops and related the ES levels with the activity-density of ground beetles and temperature. In 10 fields, we used artificial caterpillars made of plasticine and seed cards of two weed species (Taraxacum sp. and Stellaria sp.) to quantify the ESs in two sampling periods (spring and summer) and three habitat types: field defects, crops grown in standard conditions (field interiors) and crop-defect boundaries. Ground beetles were sampled using pitfall traps and classified into feeding guilds and body-size classes. Insects and mammals were the main pest predators, and predation increased in summer but did not differ among habitats. Seed predation rates for both species were significantly higher in summer. Predation upon Taraxacum seeds was higher in the field interiors, whereas the predation rate upon Stellaria seeds was significantly higher in the field interiors and defects compared to that in the crop-defect boundaries. The predation rate by insects increased with the activity-density of the medium- and large-sized carnivorous carabids, whereas the seed predation rate for both weed species was positively related to the activity-density of medium-sized herbivorous carabids. Finally, the mean and maximum temperatures were negatively linked to the predation rates on artificial caterpillars and seeds of Taraxacum, respectively. Our results suggest that these ephemeral habitats are not related to a strong decrease in ecosystem services; thus, field defects may not cause substantial changes in ES provisioning. We confirmed that ground beetles are important providers of both investigated ESs and showed that microclimatic conditions might play an important role in the regulation of ESs in agroecosystems.

Configurational crop heterogeneity increases within‐field plant diversity

Abstract Increasing landscape heterogeneity by restoring semi‐natural elements to reverse farmland biodiversity declines is not always economically feasible or acceptable to farmers due to competition for land. We hypothesized that increasing the heterogeneity of the crop mosaic itself, hereafter referred to as crop heterogeneity, can have beneficial effects on within‐field plant diversity. Using a unique multi‐country dataset from a cross‐continent collaborative project covering 1,451 agricultural fields within 432 landscapes in Europe and Canada, we assessed the relative effects of compositional and configurational crop heterogeneity on within‐field plant diversity components. We also examined how these relationships were modulated by the position within the field. We found strong positive effects of configurational crop heterogeneity on within‐field plant alpha and gamma diversity in field interiors. These effects were as high as the effect of semi‐natural cover. In field borders, effects of crop heterogeneity were limited to alpha diversity. We suggest that a heterogeneous crop mosaic may overcome the high negative impact of management practices on plant diversity in field interiors, whereas in field borders, where plant diversity is already high, landscape effects are more limited. Synthesis and applications. Our study shows that increasing configurational crop heterogeneity is beneficial to within‐field plant diversity. It opens up a new effective and complementary way to promote farmland biodiversity without taking land out of agricultural production. We therefore recommend adopting manipulation of crop heterogeneity as a specific, effective management option in future policy measures, perhaps adding to agri‐environment schemes, to contribute to the conservation of farmland plant diversity.

Temporary non-crop habitats within arable fields: The effects of field defects on carabid beetle assemblages

Landscape heterogeneity and higher complexity generally increase biodiversity in agroecosystems. Carabid beetles represent abundant and important predators of pests and weed seeds in temperate agroecosystems and are affected by landscape structure. Several studies have described the impact of permanent non-crop habitats such as woodlots, hedgerows, and grassy margins on carabid assemblages. However, temporal non-crop habitat islands within arable fields have been rarely investigated. The aim of this study was to investigate spatial distribution of carabid beetles within oilseed rape fields having temporary non-crop habitats (field defects). Field defects are areas where sown plants poorly develop due to sowing failures or extreme local conditions (soil humidity, missing nutrients). In twenty oilseed rape fields, we studied carabid assemblages collected with pitfall traps in three habitat types (field interiors, field defects, and boundaries between them) and in two sampling periods (spring and summer). Both activity-density and species richness were lower in field defects than in boundaries and field interiors during both sampling periods, indicating that field defects were not a preferred habitat for carabids. Activity-density and species richness significantly increased from spring to summer in all habitat types. Species composition of carabid assemblages significantly differed between field defects and field interiors or boundaries. Field defects were characterised by impoverished carabid assemblages and the presence of few indicator species. Interestingly, field defects with well-developed plant cover hosted carabid assemblages with species richness comparable to field interiors, indicating that re-sowing of field defects can support carabid populations within arable fields. However, the consequences of re-sowing on other arthropod taxa, e.g., insects requiring habitats with bare ground, and on populations of rare weeds need to be evaluated. The lack of effects of field defect size on carabid assemblages indicated that carabid beetles react to even very small patches with unsuitable conditions (e.g., very low humidity, high temperature or food scarcity).

Nesting habitat enhancement for wild bees within soybean fields increases crop production

Bee diversity is declining in agricultural landscapes, altering pollination services that may support or enhance crop yields. Pollination services provided by wild bees are often limited to field margins adjacent to natural habitats, but methods to increase pollinators and their ecosystem services within field interiors remain elusive. Evidence is growing that wild bees enhance yields of flowering crops, including soybean (Glycine max (L.) Merrill). We tested responses of bee communities and soybean yield following pollinator exclosure and nesting manipulation experiments within production areas of the United States. We found that pollinator exclosures resulted in lower seed yield of soybean plants, and providing nesting substrate resulted in a yield increase as well as increases in ground-nesting bees. We provide evidence for soybean-associated bees and suggest these species may benefit from supplemental nesting substrate within production areas and increase soybean yields.

Road verges support pollinators in agricultural landscapes, but are diminished by heavy traffic and summer cutting

Abstract Supporting pollinators in agricultural landscapes is important for reversing their global decline. Road verges and hedges are used by pollinators for feeding and reproduction, but few studies consider entire pollinator communities, and it remains unclear how they are distributed across adjacent verges, hedges and fields, or how they are affected by traffic and verge cutting. We surveyed flowers and pollinators, using transect counts and pan traps, to explore the role of road verges and their associated hedges in supporting pollinators in an agricultural landscape in southwest England, and the impacts of traffic and verge cutting. At 19 sites, we surveyed the road verge (verge edge and verge centre), the verge hedge (both sides), a field hedge and the field interior. Road verges and hedges had a much greater flower abundance, flower species richness and pollinator abundance than field interiors. Verge hedges had far less woody cover than field hedges, but greater flower species richness. There were fewer pollinators along verge edges (next to roads) than along verge centres (2–11 m from roads) and fewer pollinators in road verges next to busier roads. Road verges were generally cut once (in summer), and cuttings were never removed. There were substantially fewer flowers and pollinators in road verges that had been cut, even though surveys often took place many weeks after cutting. Synthesis and applications. Road verges and their associated hedges can provide hotspots of resources for pollinators in agricultural landscapes, but their capacity to do so is reduced by heavy traffic and summer verge cutting. We recommend that beneficial management for pollinators should prioritize wider road verges (at least 2 m wide), roads with less traffic, and areas away from the immediate vicinity of the road. Where possible, verge cutting should not be carried out during peak flowering times.

Pest and weed seed predation in field defects within oilseed rape crops

Non-crop habitats can act as refuge for insects in agricultural landscapes and increase ecosystem services (ESs) in neighboring arable fields. Among the different types of non-crop habitats, field defects are temporary patches where sown plants are poorly developed and other plant species emerge. These defects can be common and large in years with extreme weather conditions. However, their relevance as habitat for beneficial insects and ESs provision is unknown. Here, we quantified two ESs (pest and weed seed predation) in field defects within oilseed rape crops and related ESs levels with the activity-density of ground beetles and temperature. In 10 fields, we used artificial caterpillars made of plasticine and seed cards of two weed species (Taraxacum sp. and Stellaria sp.) to quantify ESs in two sampling periods (spring and summer) and in three habitat types: field defects, standardly grown crop (field interiors) and crop-defect boundaries. Ground beetles were sampled using pitfall traps and classified into feeding guilds and body size classes. Insects and mammals were the main pest predators and predation increased in summer, but did not differ among habitats. Seed predation rates for both species were significantly higher in summer. Predation of Taraxacum seeds was higher at field interiors, whereas predation of Stellaria was significantly higher at field interiors and defects, compared to crop-defect boundaries. Insect predation increased with the activity-density of medium and large carnivorous carabids, whereas seed predation for both weed species was positively related to the activity-density of medium-sized herbivorous carabids. Finally, temperature was negatively linked to predation of artificial caterpillars and seeds of Taraxacum.

Exploring an Odor-Baited "Trap Bush" Approach to Aggregate Plum Curculio (Coleoptera: Curculionidae) Injury in Blueberries.

This 2-year study (2013–2014) assessed the efficacy of an odor-baited “trap bush” approach to aggregate plum curculio, Conotrachelus nenuphar, adult injury, i.e., number of oviposition-scared fruit, in four commercial highbush blueberry farms in New Jersey (USA). In each farm, we compared fruit injury in bushes baited with grandisoic acid and benzaldehyde along the perimeter of trap-bush plots versus unbaited bushes in control plots. We also measured the amount of fruit injury in neighboring bushes (i.e., spillover effect) and in the plots’ interior. In both years, the amount of fruit injury by C. nenuphar adults was greater on and near odor-baited bushes in trap-bush plots compared with those on and near unbaited bushes in control plots, indicative of aggregation. Injury in unbaited bushes neighboring trap bushes was often greater than unbaited bushes in control plots, providing some evidence for a spillover effect. However, no difference in fruit injury was found between interior trap-bush and control plots. Therefore, odor-baited trap bushes can be used in blueberries to manipulate C. nenuphar foraging behavior, i.e., aggregate adults, without compromising injury in field interiors. Under this approach, insecticides could then be targeted at only a few (perimeter-row) bushes within fields rather than entire fields.

Landscape configuration, organic management, and within‐field position drive functional diversity of spiders and carabids

AbstractAgricultural management intensity and landscape heterogeneity act as the main drivers of biodiversity loss in agricultural landscapes while also determining ecosystem services. The trait‐based functional diversity approach offers a way to assess changes in community functionality across agroecosystems. We focused on carabids and spiders, because they are an important component of crop field biodiversity and have significant biological control potential.We assessed the effect of small‐ vs. large‐scale agricultural landscapes, organic farming, and within‐field position on functional diversity of spiders and carabids. We sampled pairs of organic and conventional winter wheat fields in small‐scale agricultural landscapes (former West Germany) and in neighbouring large‐scale agricultural landscapes (former East Germany). We sampled arthropods with funnel traps in transects at field edges, field interiors (15 m from edge), and field centres.The gradient from field edges towards the centres played an important role: spider body size decreased; ballooning ability increased, and hunting strategy switched from active hunters to more web‐builders—presumably, due to higher microhabitat stability in the field centre. Higher trait diversity of spiders in field edges suggested higher biocontrol potential in small‐scale agriculture. In contrast, carabid feeding switched from herbivores to carnivores, presumably due to higher pest densities inside crop fields. Furthermore, small‐scale agricultural landscapes and organic management supported larger, i.e., less dispersive carabids.Synthesis and applications. In our research, spiders were more sensitive to edge effects and less sensitive to management and landscape composition than carabids. Smaller fields and longer edges, as well as organic management increase carabid functional diversity, which may increase resilience to environmental change. Since many spider species are confined to field edges, the effect of within‐field position on functional diversity is more important in small‐scale agricultural landscapes with more edge habitat than in large‐scale agricultural landscapes. Our findings suggest that European Union policy should acknowledge the high benefits of small‐scale agriculture for the functional role of major predators such as spiders and carabid beetles, as the benefits are equal to those from a conversion to organic agriculture.

Annual flower strips support pollinators and potentially enhance red clover seed yield.

Ecological intensification provides opportunity to increase agricultural productivity while minimizing negative environmental impacts, by supporting ecosystem services such as crop pollination and biological pest control. For this we need to develop targeted management solutions that provide critical resources to service‐providing organisms at the right time and place. We tested whether annual strips of early flowering phacelia Phacelia tanacetifolia support pollinators and natural enemies of seed weevils Protapion spp., by attracting and offering nectar and pollen before the crop flowers. This was expected to increase yield of red clover Trifolium pratense seed. We monitored insect pollinators, pests, natural enemies and seed yields in a total of 50 clover fields along a landscape heterogeneity gradient, over 2 years and across two regions in southern Sweden. About half of the fields were sown with flower strips of 125–2,000 m2. The clover fields were pollinated by 60% bumble bees Bombus spp. and 40% honey bees Apis mellifera. The clover seed yield was negatively associated with weevil density, but was unrelated to bee species richness and density. Flower strips enhanced bumble bees species richness in the clover fields, with the strongest influence in heterogeneous landscapes. There were few detectable differences between crop fields with and without flower strips. However, long‐tongued bumble bees were redistributed toward field interiors and during phacelia bloom honey bees toward field edges. Clover seed yield also increased with increasing size of the flower strip. We conclude that annual flower strips of early flower resources can support bumble bee species richness and, if sufficiently large, possibly also increase crop yields. However, clover seed yield was mainly limited by weevil infestation, which was not influenced by the annual flower strips. A future goal should be to design targeted measures for pest control.