New tools to boost butterfly habitat quality in existing grass buffer strips

There are approximately 29,000 ha of grass buffer strips in the UK under Agri-Environment Schemes; however, typically they are floristically poor and as such are of limited biodiversity value. Introducing a sown wildflower component has the potential to increase dramatically the value of these buffer strips for a suite of native species, including butterflies. This study investigates management practices aiming to promote the establishment and maintenance of wildflowers in existing buffer strips. The effectiveness of two methods used to increase the establishment of wildflowers for the benefit of native butterfly species were tested, both individually and in combination. The management practices were: (1) the application of a selective graminicide (fluazifop-P-butyl) which reduces the dominance of competitive grasses; and (2) scarification of the soil which creates germination niches for sown wildflower seeds. A wildflower seed mix consisting of nine species was sown in conjunction with the scarification treatment. Responses of wildflowers and butterflies were monitored for two years after establishment. Results indicate that the combined scarification and graminicide treatment produced the greatest cover and species richness of sown wildflowers. Butterfly abundance, species richness and diversity were positively correlated with sown wildflower species richness, with the highest values in the combined scarification and graminicide treatment. These findings have confirmed the importance of both scarification as a means of introducing wildflower seed into existing buffer strips, and subsequent management using graminicides, for the benefit of butterflies. Application of this approach could provide tools to help butterfly conservation on farmland in the future.     

Attractiveness of sown wildflower strips to flower-visiting insects depends on seed mixture and establishment success

Establishing wildflower strips has been suggested as an effective measure to promote pollination services, pest control or general insect biodiversity, but little is known about the integration of these different objectives when selecting flower seed mixtures. In ten agricultural landscapes in the Netherlands, we established a wildflower strip (0.4 – 4.9 ha) with half of each strip sown with a mixture targeting longer-tongued pollinators and the other half sown with a mixture targeting shorter-tongued pollinators and natural enemies. We determined establishment success of sown wildflowers and evaluated the attractiveness of the established flower communities to multiple functional groups of flower visitors: bumblebees (long-tongued pollinators), hoverflies (short-tongued pollinators and natural enemies), and butterflies and total flower-visitor richness (indicators of wider biodiversity values). Bumblebees clearly preferred the pollinator-targeted seed mixture and were positively associated with cover of Fabaceae and negatively with Apiaceae. Hoverflies consistently preferred the natural enemy mixture and were positively associated with Apiaceae. The other target groups displayed no clear responses to seed mixture type but instead were associated with local flower richness within strips. Across sites, responses of flower-visitors to sown mixture types did not depend on wildflower strip size, proportion of surrounding semi-natural habitat, or flower variables. However, all flower-visitors except butterflies increased with increasing established cover or richness of (sown) flower species across sites. Our results suggest that, although species-rich wildflower strips may benefit several species groups, maximising different objectives involves trade-offs between functional groups that prefer short- or long-corolla flowers. Furthermore, our study suggests that sowing a wildflower mixture does not necessarily result in a vegetation with the same composition as the seed mixture as species may establish poorly or not at all. Selection of flower species for seed mixtures should therefore, in addition to insect target group, take the establishment characteristics of plant species into account.     

Habitat quality and surrounding landscape structures influence wild bee occurrence in perennial wildflower strips

Perennial wildflower strips (WFS) are known to have positive effects on wild bees in intensively used agricultural landscapes. Little knowledge exists, however, about the drivers of wild bee occurrence and if Red List species also profit from this agri-environmental scheme (AES). Therefore, we studied wild bees on transects along 20 four- to five-year-old WFS and in 10 cereal fields without AES (CONTROL sites) in differently structured landscapes across Saxony-Anhalt (Germany). In addition to local site parameters, we measured parameters of landscape structure in a 1 km radius of the WFS and CONTROL sites. The overall species richness of wild bees (125 species in total, 23 on average), including numerous specialist and Red List species, indicates a high attractiveness of perennial WFS sown with 30 native forbs. In CONTROL fields, 11 bee species (on average only one) were found.The species richness and abundance of wild bees were positively affected by local site conditions of the WFS and CONTROL sites, such as the overall number of sown and spontaneous forbs, the amount of flower rewards of sown forbs available to pollinators (Pollinator Feeding Index), and negatively by the cover of grasses. Therefore, seed mixtures of future AES should comprise a high diversity of wildflower species relevant as pollen sources for wild bees. The share of Red List wild bee species was strongly influenced by the landscape context and increased e.g. with Shannon landscape diversity and the availability of non-forest woody habitats and water bodies in the 1 km surroundings. These results suggest that besides the establishment of high-diversity WFS, semi-natural habitat structures have to be promoted to preserve rare wild bees especially in structurally simple agricultural landscapes.     

A multi-site experiment to test biocontrol effects of wildflower strips in different French climate zones

Sowing of wildflower strips has been integrated in agri-environment schemes of several European countries. Their beneficial effects on natural enemies of pest insects are well documented but (1) the desired spill-over into crop fields has not always been demonstrated, and (2) the need to adapt sown mixtures to regional climatic differences has been rarely addressed.We set up a multi-site experiment in different French climatic regions to compare effects of a wildflower strip with a grass mixture and spontaneous vegetation. The design included five regions, three to five fields per region and the three strip treatments being repeated in each field. We tested strip treatment effects on vegetation (plant species richness, plant and flower cover) and on natural enemies (hoverflies, ladybirds, aphid predation). In a subset, we further analysed the spill-over into winter wheat fields including natural enemies and pest insects (cereal aphids, leaf beetles).The wildflower strip mixture developed well in all regions and increased plant species richness and flower cover compared with grass strips and spontaneous vegetation. We found a corresponding higher hoverfly abundance and aphid predation in wildflower strips that were consistent in all regions, whereas ladybird abundance was not affected. A significantly higher hoverfly abundance, aphid predation and aphid parasitism in wheat fields close to wildflower strips indicated a spill-over. No corresponding margin treatment effects were observed for aphid and leaf beetle abundance in the field. A multivariate analysis comparing the influence of climate and vegetation parameters showed that floral cover better explained variation in natural enemy abundance and predation than climate. Our results demonstrated that similar mixtures of native plants can be used over large climatic gradients to improve biocontrol. Further research is needed to improve spill-over into crop fields and to obtain consistently strong effects in different climate zones.     

Novel management to enhance spider biodiversity in existing grass buffer strips

• 1 Grass buffer strips have been widely sown to mitigate against intensive agricultural management practices that have negatively impacted on invertebrate and plant biodiversity in arable farming systems. Typically, such strips are floristically species poor and are dominated by grasses. In the present study, we developed management practices to enhance the floristic and structural diversity of these existing strips for the benefit of spiders, a key provider of natural pest control in crops.
• 2 Across three UK arable farms, we investigated the benefits of: (i) scarification to create germination niches into which wildflower seeds were sown and (ii) the effect of graminicide applications to suppress grass dominance. Spiders were sampled twice per year (July and September) during 2008 and 2009.
• 3 The combination of scarification with wildflower seeds, as well as graminicide, resulted in the greatest wildflower cover and lowest grass cover, with a general trend of increased abundance of adult and juvenile spiders. The abundance of Pachygnatha degeeri, Bathyphantes gracilis and juvenile wolf spiders of the genus Pardosa was positively correlated with wildflower cover, probably reflecting increased prey availability. Sward structure was negatively correlated with Erigone atra, Oedothorax fuscus and juvenile Pardosa abundance.
• 4 Management that utilizes existing commonly adopted agri‐environment options, such as grass buffer strips, represents a potentially important conservation tool for increasing the quantity and quality of invertebrate habitats. This can maximize opportunities for the provision of multiple ecosystem services, including pest regulation by predators such as spiders. These management practices have the potential to be incorporated into existing U.K. and European agri‐environment schemes.

     

Establishment and management of wildflower areas for insect pollinators in commercial orchards

Sown wildflower areas are increasingly recommended as an agri-environmental intervention measure, but evidence for their success is limited to particular insect groups or hampered by the challenges of establishing seed mixes and maintaining flower abundance over time. We conducted a replicated experiment to establish wildflower areas to support insect pollinators in apple orchards. Over three years, and across 23 commercial UK orchards with and without sown wildflowers, we conducted 828 transect surveys across various non-crop habitats. We found that the abundance of flower-visiting solitary bees, bumblebees, honeybees, and beetles was increased in sown wildflower areas, compared with existing non-crop habitats in control orchards, from the second year following floral establishment. Abundance of hoverflies and other non-syrphid flies was increased in wildflower areas from the first year. Beyond the effect of wildflower areas, solitary bee abundance was also positively related to levels of floral cover in other local habitats within orchards, but neither local nor wider landscape-scale context affected abundance of other studied insect taxa within study orchards. There was a change in plant community composition on the sown wildflower areas between years, and in patterns of flowering within and between years, showing a succession from unsown weedy species towards a dominance of sown species over time. We discuss how the successful establishment of sown wildflower areas and delivery of benefits for different insect taxa relies on appropriate and reactive management practices as a key component of any such agri-environment scheme.     

Proximity to wildflower strips did not boost crop pollination on small,diversified farms harboring diverse wild bees

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

The influence of seed addition and cutting regime on the success of grassland restoration on former arable land

Questions: Can seed addition enhance the success of establishing species‐rich grassland on former arable land? Are sowing date and cutting regime important in determining success? Location: Aberdeen and Elgin, northeast Scotland, United Kingdom. Methods: A field experiment was conducted at two sites to assess the effect of seed addition, sowing date and cutting regime on the vegetation developing on former arable land, the aim being to compare the success of different treatments at producing a species‐rich grassland. Results: Sowing a seed mix resulted in the establishment of vegetation very distinct from the species‐poor vegetation dominated by perennial grasses which otherwise developed, though establishment success of the sown grassland species was highly variable between sites. Where establishment of the sown species was poor, sowing date had no significant effect on species composition, whereas the cutting regime was very important. Cutting the vegetation significantly increased both the number and abundance of sown species compared with the uncut control. Conversely, where establishment had been good, the cutting regime in the first year had little effect on species composition. Cutting the vegetation at least twice a year appeared to be the most effective management over the length of the experiment. Conclusions: Sowing a seed mixture significantly reduced the abundance and number of naturally colonising species, effectively controlling problem weed species such as Senecio jacobaea and Cirsium vulgare, highlighting the agronomic value of sowing seed mixtures on fallow farmland. The sowing of a seed mix on former arable land has demonstrated that it is feasible to create vegetation similar in character to that of species‐rich grasslands.     

Effects of perennial wildflower strips and landscape structure on birds in intensively farmed agricultural landscapes

Farmland bird populations are in a deep crisis across Europe. Agri-environment schemes (AES) were implemented by the European Union to stop and reverse the general decline of biodiversity in agricultural landscapes. In Germany, flower strips are one of the most common AES. Establishing high-quality perennial wildflower strips (WFS) with species-rich native forb mixtures from regional seed propagation is a recent approach, for which the effectiveness for birds has not yet been sufficiently studied. We surveyed breeding birds and vegetation on 40 arable fields with WFS (20 with single and 20 with aggregated WFS) and 20 arable fields lacking WFS as controls across Saxony-Anhalt (Germany). Additionally, vegetation composition, WFS quantity and landscape structure (e.g. distance to nearest woody element) were considered in our analyses. All WFS were established with species-rich native seed mixtures (30 forbs) in agricultural practice as AES. Arable fields with WFS had a higher species richness and territory density of birds than controls, confirming the effectiveness of this AES. A forb-rich vegetation was the main driver promoting birds. Flower strip quantity at the landscape level had positive effects only on bird densities, but also single WFS achieved benefits. A short distance from WFS to woody elements increased total bird species richness. However, the density of farmland birds, which are target species of these AES, were negatively affected by the proximity and proportion of woody elements in the vicinity. The effect of the proportion of non-intensively used open habitats and overall habitat richness was unexpectedly low in the otherwise intensively farmed landscape. Species-rich perennial WFS significantly promoted breeding birds. Successful establishment of WFS, resulting in high-quality habitats, a high flower strip quantity as well as implementation in open landscapes were shown to maximise the effectiveness for restoring declining and AES target farmland birds.     

Grassland restoration in practice: Do we achieve the targets? A case study from Saxony-Anhalt/Germany

Grassland restoration on arable land is the second most implemented compensation measure in Germany to counteract impacts of infrastructural projects on nature. Most grassland restoration has been carried out using standardized commercial seed mixtures with large amounts of perennial generalists, cultivars and seeds of non-local origin. To evaluate whether this current practice is appropriate for developing regional types of species-rich mesophile grasslands, we analyzed four widely used treatments in a real-world setting (48 plots): (1) sowing a non-site-specific herb-poor mixture; (2) sowing a non-site-specific herb-enriched mixture; (3) sowing a site-specific herb-enriched mixture; and (4) spontaneous regeneration. After up to nine years, restored sites differed from target grasslands in: (1) number of species; (2) abundance and dominance of target species; and (3) dominance structure. Sown fields were dominated by sown species from the beginning. Because most differences were due to increasing cover of a small number of sown species, we found little development toward regional types of species-rich mesophile grasslands. In contrast, species composition on spontaneously regenerated sites changed to a greater degree and showed gradual development toward target grasslands. The limiting factor for successful restoration on all sites was availability of propagules. On sown sites, dominance patterns - particularly of Festuca rubra cultivars - had a negative effect on immigration and development of target species. For future restoration practice, we strongly recommend avoiding standardized commercial non-local seed mixtures. In particular, highly competitive cultivars should never be used. Even spontaneous regeneration should be preferred over standardized mixtures. However, in species-poor environments enrichment with selected species is necessary to reach target state.     

Recovery of native grass biodiversity by sowing on former croplands: Is weed suppression a feasible goal for grassland restoration?

Grassland restoration on former croplands offers good opportunity to mitigate the loss of grassland biodiversity. Weed suppression can be another benefit, which becomes increasingly important because of the high recent rate of abandonment of arable lands in Central and Eastern Europe. Our aim was to evaluate the usefulness of sowing two low-diversity seed mixtures followed by annual mowing, a frequently used restoration technique, in weed suppression. We found that rapidly forming cover of sown grasses effectively suppressed short-lived weeds and their germination except in the first year. The detected dense seed bank of short-lived weeds points out the possibility and threat of later weed infestation. In the short run perennial weeds cannot be suppressed easily by sowing and annual mowing. We found that the effectiveness of seed sowing followed by mowing in weed suppression can be different on sites with different history or seed mixture. Rapidly establishing perennial weeds, such as Agropyron species were only detected in former alfalfa fields; Cirsium arvense was found in former cereal and sunflower fields but not in former alfalfa fields. We found that the rate of weed suppression and success was influenced by the seed mixtures used. In several alkali restorations the high proportion of perennial weeds was detected in year 3. In loess restorations, much lower scores were typical. This was likely caused by the different seed mixture used. The loess seed mixture contained seeds of a clonally spreading tall-grass, Bromus inermis, which could compete more effectively with clonally spreading weeds, than could short grass species with or without tussock forming. Our findings indicate that post-restoration management require carefully designed actions that are fine-tuned addressing specific threats at the site level.     

Vegetation development in sown field margins and on adjacent ditch banks

The creation of temporal and newly sown field margins for 6 years is a common agri-environment scheme (AES) in the Netherlands. Conservation profits resulting from AES vary over different areas and need further studying. We examined plant species richness in such field margins and adjacent ditch banks in the province of Zeeland, where these linear elements do not experience plant biomass removal after mowing as management strategy. First, during 2 years, we inventoried field margins sown with a wildflower mixture and related the species composition and richness to the age of the margins. In a second assessment, we studied plant species richness on ditch banks protected from arable fields by these margins. Major clusters in a principal component analysis (PCA) on species composition in the field margins showed a succession from sown and ruderal annual species (year 1), to sown perennial species (year 2) and ending with a dominance by tussock forming grass species and Urtica dioica (year 5–6). Total plant species richness decreased with increasing age of the margins, and this was caused by the combination of a decline in sown species and a stable number of not-sown species. The presence of field margins during several years did not result in an increase in plant species richness on adjacent ditch banks. In both the field margins and on the ditch banks, mowing management is not followed by the removal of the cuttings. For plant conservation, the results of these field margins are disappointing, probably due to the lack of a proper management. Therefore, we recommend implementing a hay-making and opening management, to increase plant richness and to reduce noxious weeds in the margins and on the ditch banks.     

What can sown wildflower strips contribute to butterfly conservation?: an example from a Swiss lowland agricultural landscape

The objective of this study was to compare butterfly abundances and diversity between wildflower strips and extensively used meadows to identify which butterfly species can be supported by establishing wildflower strips. Butterflies were recorded along transects during one season in twenty-five sown wildflower strips and eleven extensively used meadows in a Swiss lowland agricultural landscape (600 ha). In total 1,669 butterflies of 25 species were observed (25 in the strips, 18 in meadows). This can be related to 38 species recorded in the region (lowland part of Kanton Fribourg) within the Swiss Biodiversity Monitoring Programme. In wildflower strips the number of butterflies per transect meter was significantly higher than in the meadows, but there was no significant difference in species richness. Butterfly communities, though, were quite different between the two habitat types. Habitat type, abundances of flowering plants and presence of forest within 50 m were identified as factors influencing butterfly species richness. Butterfly abundances were affected by habitat type and abundance of flowering plants. In wildflower strips, 65% of all flower visits by butterflies were observed on Origanum. It can be concluded that sown wildflower strips can support a substantial part of a regions species pool. This is mostly true for common species, but can apply to rare species when, for example, larval food plant requirements are met.     

Larger patches of diverse floral resources increase insect pollinator density,diversity, and their pollination of native wildflowers

Native wildflower plantings can be used to provide nutritional resources to support pollinating insects, yet the effects of planting size and bloom richness on the density, diversity, and function of these insects are not well understood. We established stands of twelve native flowering perennial plant species in replicated plots ranging in size from 1 to 100 m². These plots were sampled for insect pollinators, bloom richness, and seed production by three wildflower species. Honeybees, wild bees, and hoverflies all responded positively to increasing flower richness, whereas particular insect pollinator groups responded differently to the size of the flowering plant area. The density of honeybees and hoverflies was not affected by increasing flowering patch size, whereas in general, wild bees were observed at higher density and diversity in the 30 and 100 m² patches. Increasing wildflower patch size, and thus wild bee density, resulted in greater seed set in the sampled wildflowers. These results indicate that wild bees are sensitive to the area and richness of floral resources in patches, even at relatively small scales. Therefore, larger wildflower plantings with more diverse flower species mixes are more suitable for the conservation of wild pollinators and reproduction of sown species.     

Vegetation development after a large scale restoration of species-rich grasslands in a Central European floodplain

Large scale restoration using local high-diversity seed mixture combined with turf transfer was applied on ex-arable land in the Morava River floodplain in the western Slovakia in the years 1999–2012. The post-restoration vegetation development was recorded during 12 years after the restoration using floristic records per restored polygons with cover estimation in simple 3-degree scale. Temporal changes in species composition were evaluated by gradient analysis and number of characteristic grassland and ruderal species on restored sites was analysed by general linear models. Species composition changed gradually towards the species composition typical for species-rich floodplain grasslands, but the trajectory was not straightforward and several irregularities were observed. They were probably induced by extreme weather events (drought, floods). The decrease in ruderal species and increase in the number of typical floodplain grassland species were observed, when floodplain grassland species permanently outcompeted ruderal species since 8th year after the restoration. However the development in large scale was slower, than expected from previous small-scale experiments, it is evident, that combination of local seed mixture sowing with a turf transfer is a feasible method for the restoration of species-rich floodplain grasslands from arable land.     

Vegetation development and floristical diversity of newly created sown and unsown field margin strips on ex arable land during the first 3 successional years

Early succesion of newly created sown/unsown margin strips on ex arableland, managed by two cuttings per year with/without removal of cuttings was characterised by the replacement of annuals in favour of perennials, a steadily increase in the importance of monocots and a decrease in non N-fixing dicots. Mowing with removal of cuttings delayed this succession pattern. Sorenson's qualitative similarity index (based solely on species occurrence) revealed that species composition of the sown communities (in terms of species occurrence) became increasingly similar to the unsown plots. Furthermore convergence in vegetation composition between sown and unsown plots occurred also in terms of species importance as assessed by Sorenson's quantitative index (based on the combination of species occurrence and importance). Similarity in species importance (but not of species occurrence) was significantly enhanced by cutting with removal of cuttings. During the first 3 successional years, species diversity of sown and unsown communities converged in time, irrespective of mowing regime or location. The decrease in species diversity, number of sown wildflower species and wildflower density of sown communities was more pronounced under a mowing regime without removal of cuttings. The annual addition of mown roadside herbage significantly enhanced species richness but not the importance of dicots.     

Long‐term effectiveness of sowing high and low diversity seed mixtures to enhance plant community development on ex‐arable fields

Questions: How is succession on ex‐arable land affected by sowing high and low diversity mixtures of grassland species as compared to natural succession? How long do effects persist? Location: Experimental plots installed in the Czech Republic, The Netherlands, Spain, Sweden and the United Kingdom. Methods: The experiment was established on ex‐arable land, with five blocks, each containing three 10 m × 10 m experimental plots: natural colonization, a low‐ (four species) and high‐diversity (15 species) seed mixture. Species composition and biomass was followed for eight years. Results: The sown plants considerably affected the whole successional pathway and the effects persisted during the whole eight year period. Whilst the proportion of sown species (characterized by their cover) increased during the study period, the number of sown species started to decrease from the third season onwards. Sowing caused suppression of natural colonizing species, and the sown plots had more biomass. These effects were on average larger in the high diversity mixtures. However, the low diversity replicate sown with the mixture that produced the largest biomass or largest suppression of natural colonizers fell within the range recorded at the five replicates of the high diversity plots. The natural colonization plots usually had the highest total species richness and lowest productivity at the end of the observation period. Conclusions: The effect of sowing demonstrated dispersal limitation as a factor controlling the rate of early secondary succession. Diversity was important primarily for its‘insurance effect’: the high diversity mixtures were always able to compensate for the failure of some species.     

Butterflies and bumblebees in greenways and sown wildflower strips in southern Sweden

Greenways have recently been established in some intensively farmed areas of South Sweden in order to enhance recreation opportunities and biodiversity, but the effects of these green structures on biodiversity have not yet been determined. In this study, greenways and experimental sown wildflower strips were investigated for butterfly and bumblebee diversity. In total, 1,769 butterflies of 18 species and 1,216 foraging bumblebees of eight species were recorded. Sown wildflower strips proved to support much higher abundances and species numbers of butterflies and bumblebees than greenways, with 86% of all butterflies and 83% of all bumblebees being observed in the sown flower strips. However, in both types of green structure mostly common species were found. Counts of flower visits showed that Knautia, Centaurea and Cirsium were the most commonly visited plant species. The greenways studied did not seem to fulfil their function of enhancing biodiversity—at least not for butterflies and bumblebees. However, these greenways could easily be improved for common bumblebee and butterfly species by sowing wildflower strips along their margins.     

Augmenting flower trait diversity in wildflower strips to optimise the conservation of arthropod functional groups for multiple agroecosystem services

Sown wildflower strips are increasingly being established in Europe for enhancing arthropod conservation and the provision of ecosystem services, including biotic pollination and natural pest control. Here we use floral traits to identify different plant functional effect groups. Floral resources were provided in four experimental levels characterised by a cumulatively increasing flower trait diversity and vegetation stand complexity. The first level consisted of a bare control strip, whilst in each subsequent level three wildflower species with different functional traits were added (Level 0: control; Level 1: three Apiaceae species; Level 2: three Apiaceae and three Fabaceae species; Level 3: three Apiaceae, three Fabaceae species, and Centaurea jacea (Asteraceae), Fagopyrum esculentum (Polygonaceae), Sinapis alba (Brassicaceae)). Plots with sown wildflower strip mixtures were located adjacent to experimental plots of organically-managed tomato crop, which is attacked by multiple pests and partially relies on bees for fruit production, and hence dependent on the provision of pollination and pest control services. Results obtained here show that the inclusion of functionally diverse wildflower species was associated with an augmented availability of floral resources across time, and this increased the abundance of bees and anthocorids throughout the crop season. Several natural enemy groups, such as parasitoids, coccinelids and ground-dwelling predators, were not significantly enhanced by the inclusion of additional flower traits within the strips but the presence of flower resources was important to enhance their conservation in an arable cropping system.     

Agri‐environment schemes targeting farmland bird populations also provide food for pollinating insects

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