Flower Richness Research Articles

The importance of biotic interactions in distribution models of wild bees depends on the type of ecological relations, spatial scale and range

Studies have found that biotic information can play an important role in shaping the distribution of species even at large scales. However, results from species distribution models are not always consistent among studies and the underlying factors that influence the importance of biotic information to distribution models, are unclear. We studied wild bees and plants, and cleptoparasite bees and their hosts in the Netherlands to evaluate how the inclusion of their biotic interactions affects the performance of species distribution models. We assessed model performance through spatial block cross‐validation and by comparing models with interactions to models where the interacting species was randomized. Finally, we evaluated how, 1) spatial resolution, 2) taxonomic rank (genus or species), 3) degree of specialization, 4) distribution of the biotic factor, 5) bee body size and 6) type of biotic interaction, affect the importance of biotic interactions in shaping the distribution of wild bee species using generalized linear models (GLMs). We found that the models of wild bees improved when the biotic factor was included. The model performance improved the most for parasitic bees. Spatial resolution, taxonomic rank, distribution range of the biotic factor and degree of specialization of the modelled species all influenced the importance of the biotic interaction to the models. We encourage researchers to include biotic interactions in species distribution models, especially for specialized species and when the biotic factor has a limited distribution range. However, before adding the biotic factor we suggest considering different spatial resolutions and taxonomic ranks of the biotic factor. We recommend using single species or genus data as a biotic factor in the models of specialist species and for the generalist species, we recommend using an approximate measure of interactions, such as flower richness.

Pollination knowledge among local farmers in northern Tanzania and the role of traditional agroforestry practices in promoting pollinator forage plants

Pollination services by insects contribute strongly to food security and ecosystem stability. However, especially in Africa, little is known about farmer's knowledge and awareness of pollination services. Here, we first surveyed home garden farmers about their knowledge on pollination services, and their ability to recognize insect pollinators. Then we evaluated their home gardens for the availability of pollinator forage resources. We found that a majority of the farmers (89.1%) were not aware of pollination services and that awareness was higher for males and those with higher education levels. All farmers were able to recognize at least one insect species (especially, Apis mellifera) but most farmers did not know them as pollinators. We also found that 293 woody plant species from 62 families in Chagga home gardens (CHGs), provided insect pollinator forage. There was higher alpha diversity for exotic forage plants but higher gamma diversity for natives. The increase in diversity of pollinator forage plants reduced the temporal variability of flower richness. Our findings suggest that farmers should be made more aware of pollination services as well as insect pollinators specifically regarding their benefits to increase willingness to conserve them. Awareness programs should be accessible to women and those with little formal education as they exhibit the least knowledge. Also, various media tools should be used for effective dissemination to the different target audiences. Our findings also provide evidence that if managed properly some traditional agricultural land use systems can enhance pollination services by providing diverse forage resources for insect pollinators.

Flower richness is key to pollinator abundance: The role of garden features in cities

Urban areas can be both detrimental for pollinators or function as suitable habitats, depending on the land-use type, the urban context and the pollinator group in focus. Urban green spaces, including gardens, parks or cemeteries can provide essential resources for a wide range of pollinator groups, like wild bees, hoverflies and beetles. Urban community gardens can be particularly structurally complex and harbour a diverse range of nesting and food resources for pollinators. However, we know little about how garden features may vary with the urban context of gardens and which specific garden features can increase the abundance of pollinators in general and of different pollinator groups.Over two summer seasons, we recorded garden features and pollinators using flower observations in 33 urban community gardens in Munich and Berlin, Germany. We examined how garden features differ amongst urban community gardens from three urbanisation categories, and analysed the effects of garden features such as floral and nesting resources and landscape imperviousness (as indicator of urbanisation) on pollinator abundance, richness and diversity.In more urbanised gardens, flower richness and bare substrate were less prevalent. Flower richness was positively correlated with overall pollinator abundance, richness and diversity as well as with the abundances of all pollinator taxa excluding beetles. Landscape imperviousness was negatively correlated with hoverfly and beetle abundances. Hoverflies also decreased with increasing bare substrate and wasp abundance decreased with increasing deadwood availability. Our findings highlight the important role of flower richness for insect conservation in urban management and show that pollinator taxa react differently to garden features and urbanisation. To support pollinating insects, gardeners can increase flower richness, especially in highly urbanised areas.

Transect walks and malaise traps differ in temperature sensitivity but reveal consistent drivers of pollinator richness

Abstract While transect walks have long been the preferred monitoring method for many flying insect taxa, malaise traps combined with DNA metabarcoding have gained growing prominence. However, it remains unclear whether both methods reveal comparable species richness and the same ecological drivers along environmental gradients. We selected three groups of pollinators (wild bees, hoverflies and butterflies) and one group of herbivores (grasshoppers) as functionally important and conservation‐relevant model groups, comparing results of both methods along an elevational gradient in the German Alps. Across the study region, both methods detected a similarly high species richness of pollinators with ~50% overlap of species pools, but transect walks revealed more species per site, especially in higher elevations and under low temperatures. Body size spectra differed between methods, with on average more large butterfly and more small bee species in transect walks. Nevertheless, temperature and flower richness were consistent drivers of pollinator richness, independent of the sampling method. Grasshopper richness from transect walks was considerably higher than from malaise traps. Both methods identified temperature and only malaise traps also identified management as drivers of grasshopper richness. We conclude that malaise traps are principally suitable substitutes for the more time‐consuming pollinator transect walks. However, the effectiveness of these passive traps is more susceptible to changes in sampling temperature, and in some pollinator groups, body size classes are presented differently, which is important to consider during analyses. For grasshoppers, transect walks appear to be more suitable to assess species richness, as considerably more species can be monitored.

Organic compost belowground and floral diversity aboveground interactively shape beneficial insects in urban gardens

Abstract Plant diversity aboveground can exert top‐down pressure on herbivores by attracting predatory insects, while organic soil amendments rich in beneficial microbes can limit herbivores from the bottom‐up by enhancing plant defensive chemistry. Aboveground and belowground forces always operate simultaneously to shape herbivore pressure, but understanding how they interact is a longstanding and persistent challenge. Here, we examine how organic composts mediate the effects of plant diversity across trophic levels, using zucchini plants (Cucurbita pepo) as a study system. Over two field seasons, we manipulated vermicompost treatments in 18 experiments in school gardens that varied in surrounding plant and floral resource diversity and measured responses of insect herbivores and their natural enemies. Vermicompost strengthened a positive relationship between flower richness and foliar‐feeding omnivores, suggesting that robust reservoirs of omnivores at flower‐rich sites mounted stronger responses to compost‐treated host plants. Predators increased with flower richness, but were not affected by vermicompost. Net outcomes of vermicompost and plant diversity were neutral for herbivores. Synthesis and applications. Altogether, our results reveal that bottom‐up factors protecting plants are modified by their environmental context, and may more effectively attract natural enemies in landscapes with diverse floral resources. Therefore, we recommend augmentation of biodiversity aboveground (i.e. floral resources) together with biodiversity belowground (organic soil amendments) to strengthen crop protection.

Using photographs and deep neural networks to understand flowering phenology and diversity in mountain meadows

AbstractMountain meadows are an essential part of the alpine–subalpine ecosystem; they provide ecosystem services like pollination and are home to diverse plant communities. Changes in climate affect meadow ecology on multiple levels, for example, by altering growing season dynamics. Tracking the effects of climate change on meadow diversity through the impacts on individual species and overall growing season dynamics is critical to conservation efforts. Here, we explore how to combine crowd‐sourced camera images with machine learning to quantify flowering species richness across a range of elevations in alpine meadows located in Mt. Rainier National Park, Washington, USA. We employed three machine‐learning techniques (Mask R‐CNN, RetinaNet and YOLOv5) to detect wildflower species in images taken during two flowering seasons. We demonstrate that deep learning techniques can detect multiple species, providing information on flowering richness in photographed meadows. The results indicate higher richness just above the tree line for most of the species, which is comparable with patterns found using field studies. We found that the two‐stage detector Mask R‐CNN was more accurate than single‐stage detectors like RetinaNet and YOLO, with the Mask R‐CNN network performing best overall with mean average precision (mAP) of 0.67 followed by RetinaNet (0.5) and YOLO (0.4). We found that across the methods using anchor box variations in multiples of 16 led to enhanced accuracy. We also show that detection is possible even when pictures are interspersed with complex backgrounds and are not in focus. We found differential detection rates depending on species abundance, with additional challenges related to similarity in flower characteristics, labeling errors and occlusion issues. Despite these potential biases and limitations in capturing flowering abundance and location‐specific quantification, accuracy was notable considering the complexity of flower types and picture angles in this dataset. We, therefore, expect that this approach can be used to address many ecological questions that benefit from automated flower detection, including studies of flowering phenology and floral resources, and that this approach can, therefore, complement a wide range of ecological approaches (e.g., field observations, experiments, community science, etc.). In all, our study suggests that ecological metrics like floral richness can be efficiently monitored by combining machine learning with easily accessible publicly curated datasets (e.g., Flickr, iNaturalist).

Pan traps: An effective tool for monitoring phenological changes in insect floral visitors and their relationship with floral resources in a coastal Mediterranean forest

Precise monitoring of insect floral visitors and their relationship with floral resources throughout the flowering season provides baseline information to help us understand long-term changes in plant-pollinator interactions and improve pollinator conservation strategies. Pan traps are one of the methods most used for monitoring insect floral visitors and several studies have already linked the abundance and richness of these floral visitors with floral resources. However, less research has been conducted into the effectiveness of pan traps for monitoring phenological changes in the floral visitor community with regard to floral resources. We used pan traps to study the species composition and the abundance of insect floral visitors and their relationship with flower richness in a coastal forest throughout the entire flowering season for two consecutive years. Captures were confirmed to be floral visitors through field survey studies. Pan traps were effective for revealing changes in the abundance and species composition of floral visitor communities during and between years that correlated with changes in floral richness and species composition. Changes in floral visitor abundance showed a different bias in their association with floral richness. Thus, while Hymenoptera and Diptera abundance tended to be negatively correlated with floral richness, Coleoptera abundance tended to be positively correlated, although such correlations could change from year to year. There were two significantly different groups of flowering plant and floral visitor species: one in spring and the other in summer. Each period was characterized by unique overlap between some floral visitors and their floral resources, suggesting that to monitor floral visitors effectively both communities need to be considered. Interestingly, the floral phenology in this coastal forest extended longer than that of more inland communities, so reliable monitoring of floral visitors throughout the floral season may help us to better understand the role of coastal plant communities in the stabilization of the pollinator networks of more inland communities. Overall, phenology patterns need to be taken into account for pan trapping to become an effective methodology for monitoring floral visitor communities, considering both intra-year (spring and summer communities) and inter-year variations.

Are bees attracted by flower richness? Implications for ecosystem service-based policy

Agri-environmental policies aim to reverse the degradation of ecosystem services in rural landscapes by implementing biodiversity-based land-use solutions. One such agri-environmental measure is the contract for bee-forage fields in Estonia. We developed a multi-site experiment to estimate the effect of plant diversity on the quality properties of flower-based services, such as flowering duration (indicating functional stability) and the foraging activity of insect pollinators (indicating functional intensity). Each site consisted of eight randomly ordered strip-segments forming a flower diversity gradient.The period of abundant flowering was longer in all kinds of species mixture than in monocultures. However, the foraging activity of honey bees and bumblebees was greatest in monocultures and in a low-diversity mixture, while a balanced high-diversity mixture was least attractive. Foraging activity was lowered when an abundant melliferous plant species was flowering within a high-diversity mixture (i.e. high species richness, but low evenness). The extended flowering of species mixtures did not compensate for the lower daily visitation rate.We challenge the largely biodiversity-oriented agricultural policy designs. This case study provides evidence that plant species richness is not a comprehensive indicator of the service provision quality of an ecosystem. Specifically, low-diversity flower areas are the best foraging sites for bees and other flower visitors. A field mosaic of various monocultures and low-diversity mixtures seems to be the ecologically most efficient rural landscape design to support bees and other potential pollinators. Suggested and marketed pollinator-oriented seed mixtures should be quantitatively tested for ecological efficiency.

Butterflies are not a robust bioindicator for assessing pollinator communities, but floral resources offer a promising way forward

Monitoring pollinators is crucial for the evaluation of biodiversity and potential pollination services. Yet, efficiently monitoring multiple taxa over large areas can be costly. An alternative approach is using simple species bioindicators that represent the entire pollinator community. One of the requirements of a good bioindicator is that it can be easily identified to lower taxonomic levels and be sensitive to changes in habitat. This is the case for butterflies, a taxon for which many countries have a country-wide long-term monitoring scheme. We tested whether butterfly diversity can be used to predict diversity of bees and hoverflies both spatially and temporally. We surveyed 42 transects of the Dutch Butterfly Monitoring Scheme in 2020, to record species richness and abundance of butterflies, bees and hoverflies. We also recorded flower area and richness in the pollinator transects. To test whether pollinators with similar functional traits are more closely correlated than the entire pollinator community, we categorized bee and butterfly species according to their diet breadth (polyphagous vs. non-polyphagous), nitrogen-affinity (nitrophobous vs. nitrophilous larval resources) and body size. We used the same methods to test for temporal correlations over seven years for one site in Spain. Butterfly richness was not spatially correlated with bee richness (Pearson's r = 0.13), nor were the two taxa temporally correlated (Pearson's r = 0.02). Interestingly, hoverfly richness was spatially correlated with butterfly richness (Pearson's r = 0.43) and with bee richness (Pearson's r = 0.36) in the Netherlands and, hence, hoverflies might be slightly more suitable as a bioindicator of pollinator diversity in this area. Abundance of all three taxa showed no significant inter-correlation, except for correlations between diet specialist bees and butterflies (Pearson's r = 0.39). Importantly, all three taxa were strongly correlated with flower richness, but they varied in their preferences for host plant families. This is in line with 75% of the plant-pollinator studies finding significant positive relations. For monitoring schemes to be effective in informing better pollinator conservation, they should expand to include bees and hoverflies as well as simple indicators of habitat quality such as floral resources.

Temporally stacked bee forage species distribution modeling for flower abundance mapping

Predicting spatial distribution of flowering forage availability is critical for guiding migratory beekeeping decisions.Species distribution modelling (SDM) is widely used to predict the geographic distribution or species ranges. Stacked distributions of multiple species (S-SDM) have been used in predicting species richness or assemblages. Here, we present a method for stacking SDMs based on a temporal element, the flowering phenology of melliferous flora species. First, we used presence-only data for thirty key forage species used for honey production in Western Australia, combined with environmental variables for predicting the geographic distribution of species, using MaxEnt software. The output distribution grids were then stacked based on monthly flowering times of each species to develop grids representing the richness of flowering species by grid cell. While designed for modelling flowering forage availability for a migratory beekeeping system, the approach can be used for predicting temporal forage availability for a range of different fauna that rely on melliferous flora.•How to use temporally stacked species distribution modelling for generic distribution of flowering availability using presence-only data.•A procedure for developing flowering richness and availability grids.

Urban intensity and flower community structure drive monkey beetle assemblage in Cape Town

Background: Urban landscapes present an important opportunity for pollinator conservation, but little is known about the status and distribution of pollinator populations in urban habitats in Africa. This represents a major gap in the development of a global understanding of urban pollinators – particularly from the rapidly urbanising context. This study uses a speciose clade of flower-visiting beetles (Coleoptera: Scarabaeidae: Hopliini) to explore patterns of pollinator distribution in a major metropolitan area in South Africa. Objectives: We investigated community composition across gradients of urban intensity (defined according to the percentage of soil-sealing within 1 km2 of each sampling location) and socio-economic status to determine pollinator responses to these urban landscape effects. Methods: A selection of 142 sites were surveyed twice in the austral spring seasons of 2018 and 2019. Data were collected on habitat structure, flower diversity, and pollinator diversity. Results: The study found that different feeding guilds of monkey beetles favoured different levels of urban intensity and that beetle richness significantly correlated with flower richness. It did not, however, correlate with diversity indicating that abundance is less impacted than the number of species present. Monkey beetles with moderate sensitivity to urban intensity benefitted from the presence of preferred species of flowers. Conclusion: Overall, the findings demonstrate the importance of plant community assemblage in supporting urban monkey beetles. We recommend landscaping with preferred flower species in urban parks to support urban pollinators.

How Does Vegetation Landscape Structure of Urban Green Spaces Affect Cultural Ecosystem Services at Multiscale: Based on PLS-SEM Model

Benefits of cultural ecosystem services (CESs) of urban green spaces (UGSs) for human health and general well-being have been widely recognized. Optimizing the landscape structure of green vegetation and improving CES are essential to reduce environmental inequality, and detecting the determinant landscape features that influence CES at multi-scale is the first step. Using partial least squares structural equation modeling (PLS-SEM), we evaluated multiscale effects of vegetation landscape structure of UGS on residents’ perceptions of CES in 40 residential communities in Zhengzhou city, China. According to our results, at the micro-scale level in a single residential community, public activity spaces within green spaces, particularly large size of open spaces, was the most critical factor affecting residents’ perceptions of recreational services, which provided a multifunctional landscape, with opportunities for multiple recreational leisure activities and entertainment. Then, the percentage of vegetation coverage in green spaces, and large vegetation patches that can significantly improve residents’ perceptions of CES and were identified in the natural landscape. At the ecosystem level and species community level, although vegetation structure contributed little to the level of CES, an open vegetation structure with a large area of grass cover was particularly beneficial to increase aesthetic services, and both richness of flowers and ornamental trees improved residents’ spiritual perception. However, our findings suggest that improving the management of green space vegetation is the most effective and direct way of improving CES and resolving environmental inequities between residential communities with different vegetation coverage and infrastructure, and we suggest that future research should explore residents’ subjective perceptions of both vegetation and landscape structure of UGS at larger spatial scale.

꽃의 이미지를 활용한 업스타일 연구

Recently, the average age of marriage has gradually increased, and the micro-wedding has become more popular. Under these circumstances, this study is meaningful in that it aimed to examine the diversity of updo hairstyles in simplified wedding culture. In updo hair accessories, there has been an attempt to change from artificial jewelry to natural flowers. Even during such transition, the pursuit of beauty remains unchanged. As the richness and beauty of flowers in diverse colors and shapes make people happy, this study attempted to express beauty, using up-styling techniques and elements such as shape, texture and color with flower images as motives with a goal of making guests happy and satisfied. To meet a bride’s desire to remember her wedding moment forever and make her more beautiful with a flower-based updo style, this study created hairstyles with flowers as motives for a blessed wedding. Specifically, yellow chrysanthemum and green calla symbolize ‘wealth & authority’ and ‘love of thousand years’ respectively while pink Lamprocapnosand green rose represent ‘love in heat shape’ and ‘world of imagination’ each.

Responses of hover fly diversity and abundance to urbanisation and local attributes of urban greenspaces

Urban greenspaces are vital refugia for insect biodiversity, but seasonal fluctuation responses of insect taxa to urbanisation and local attributes of urban greenspaces are not well known. Regions with mild temperate climates and winter-flowering plants have active winter pollinators that are often neglected. A thorough knowledge of the seasonally fluctuating ecological needs of insects is essential for adequate insect-friendly greenspace management. Hover flies are cosmopolitan inhabitants of urban greenspaces where they provide multiple critical ecosystem services such as pollination and pest control. Our study uses a multi-scale approach to determine the seasonal effects of urbanisation on hover fly richness, abundance, and assemblages in urban greenspaces. We selected 30 sites along an urbanisation gradient (as measured by human population density) in Sydney, Australia, and sampled each site over a year across seasons. We found that hover fly species richness was higher in winter and spring than in summer, while abundance was highest in winter and lowest in summer. Our results also show that a combination urbanisation and local attributes of urban greenspaces (flower richness, flower abundance, human population density, and proportion of native flowers) combined to affect hover fly species richness and abundance in seasonally dependant ways. Hover flies are especially abundant and diverse during winter- a time of the year when other native floral visitors are less active. Thus, hover flies may be important pollinators of the large community of winter-flowering plants in Australia. Urban greenspaces can be made more hospitable to hover flies by implementing simple management initiatives, such as complementing native floral resources with non-native flowers in periods of scarcity.

Automatic counting of rapeseed inflorescences using deep learning method and UAV RGB imagery.

Flowering is a crucial developing stage for rapeseed (Brassica napus L.) plants. Flowers develop on the main and branch inflorescences of rapeseed plants and then grow into siliques. The seed yield of rapeseed heavily depends on the total flower numbers per area throughout the whole flowering period. The number of rapeseed inflorescences can reflect the richness of rapeseed flowers and provide useful information for yield prediction. To count rapeseed inflorescences automatically, we transferred the counting problem to a detection task. Then, we developed a low-cost approach for counting rapeseed inflorescences using YOLOv5 with the Convolutional Block Attention Module (CBAM) based on unmanned aerial vehicle (UAV) Red-Green-Blue (RGB) imagery. Moreover, we constructed a Rapeseed Inflorescence Benchmark (RIB) to verify the effectiveness of our model. The RIB dataset captured by DJI Phantom 4 Pro V2.0, including 165 plot images and 60,000 manual labels, is to be released. Experimental results showed that indicators R2 for counting and the mean Average Precision (mAP) for location were over 0.96 and 92%, respectively. Compared with Faster R-CNN, YOLOv4, CenterNet, and TasselNetV2+, the proposed method achieved state-of-the-art counting performance on RIB and had advantages in location accuracy. The counting results revealed a quantitative dynamic change in the number of rapeseed inflorescences in the time dimension. Furthermore, a significant positive correlation between the actual crop yield and the automatically obtained rapeseed inflorescence total number on a field plot level was identified. Thus, a set of UAV- assisted methods for better determination of the flower richness was developed, which can greatly support the breeding of high-yield rapeseed varieties.

Sown wildflowers between vines increase beneficial insect abundance and richness in a British vineyard

Abstract Traditional vineyards are generally intensive monocultures with high pesticide usage. Viticulture is one of the fastest‐growing sectors of English agriculture, although there is currently limited research on habitat management practices. In a vineyard in East Sussex, England, we tested five inter‐row ground cover treatments on their potential in supporting beneficial insects: two commercially available seed mixes (meadow mix and pollen and nectar mix), a wild bee seed mix (formulated based on pollinator foraging preferences), natural regeneration, and regularly mowed grass. Over two years, from May to August, we conducted monthly floral surveys and insect surveys using transect walks and pan traps. The abundance and richness of flowers in the natural regeneration treatment were twice that of the regularly mown inter‐row treatment. By year 2, the abundance of “total insects” sampled was significantly higher in the wild bee mix compared to mown. Likewise, there was a significant effect of treatment type on pollinator richness, with a higher mean richness found in wild bee mix. Solitary wasp family richness was highest in the natural regeneration treatment and lowest in the mown treatment. Given the rapid growth and lack of specific environmental recommendations for British viticulture, we demonstrate a simple and effective approach for supporting beneficial insects and ecosystem services. Promotion of perennial wildflowers through sowing or allowing natural regeneration in inter‐row ground cover in vineyards has the potential to boost biodiversity in vineyards on a large scale if widely adopted.

Different types of semi‐natural habitat are required to sustain diverse wild bee communities across agricultural landscapes

Abstract Semi‐natural habitats provide important resources for wild bees in agricultural landscapes. Landscapes under management are dynamic and floral resources fluctuate in space and time. Thus, promoting different semi‐natural habitat types within landscapes could be key to support diverse bee meta‐communities throughout the season. Here, we integrate analyses of α‐diversity (species richness) and β‐diversity and species‐habitat networks to examine the relative contribution of all major semi‐natural habitats to wild bee meta‐communities in agricultural landscapes. We sampled extensively and conventionally managed meadows, flower strips, hedgerows and forest edges in spring, early and late summer in 25 landscapes in Switzerland. Habitat types varied in their importance for wild bees throughout the season: While extensively managed meadows supported more rare species, habitat specialists and bee species overall than the other habitat types, flower strips were most important later in the season. Each of the five investigated habitat types harboured relatively unique sets of species with different habitats generally acting as distinct modules in the overall bee‐habitat network. Not only flower richness in a habitat per se, but also flower‐habitat network properties (habitat strength and functional complementarity) were good predictors of wild bee richness. In addition to local floral richness, landscape composition and configuration interactively influenced β‐diversity patterns across habitats. Synthesis and applications. Our study highlights the value of pollinator‐habitat network analysis to inform pollinator conservation management at the landscape scale, especially when combined with information on floral resources and flower‐habitat networks. Maintaining different types of semi‐natural habitats offers diverse and complementary resources throughout the season, which are crucial to sustain diverse wild bee meta‐communities in agricultural landscapes. Particularly meadow extensification schemes can play a key role in safeguarding rare and specialist species in these landscapes. While locally a high flower richness promoted bee abundance and richness in general, our results indicate that increasing connectivity between habitat patches in landscapes dominated by arable crops appears to improve species exchange between local bee communities of different habitats, thereby possibly increasing their resilience to disturbances.

Pollinator richness, pollination networks, and diet adjustment along local and landscape gradients of resource diversity.

Loss of habitats and native species, introduction of invasive species, and changing climate regimes lead to the homogenization of landscapes and communities, affecting the availability of habitats and resources for economically important guilds, such as pollinators. Understanding how pollinators and their interactions vary along resource diversity gradients at different scales may help to determine their adaptability to the current diversity loss related to global change. We used data on 20 plant–pollinator communities along gradients of flower richness (local diversity) and landscape heterogeneity (landscape diversity) to understand how the diversity of resources at local and landscape scales affected (1) wild pollinator abundance and richness (accounting also for honey bee abundance), (2) the structure of plant–pollinator networks, (3) the proportion of actively selected interactions (those not occurring by neutral processes), and (4) pollinator diet breadth and species' specialization in networks. Wild pollinator abundance was higher overall in flower‐rich and heterogeneous habitats, while wild pollinator richness increased with flower richness (more strongly for beetles and wild bees) and decreased with honeybee abundance. Network specialization (H 2′), modularity, and functional complementarity were all positively related to floral richness and landscape heterogeneity, indicating niche segregation as the diversity of resources increases at both scales. Flower richness also increased the proportion of actively selected interactions (especially for wild bees and flies), whereas landscape heterogeneity had a weak negative effect on this variable. Overall, network‐level metrics responded to larger landscape scales than pollinator‐level metrics did. Higher floral richness resulted in a wider taxonomic and functional diet for all the study guilds, while functional diet increased mainly for beetles. Despite this, specialization in networks (d′) increased with flower richness for all the study guilds, because pollinator species fed on a narrower subset of plants as communities became richer in species. Our study indicates that pollinators are able to adapt their diet to resource changes at local and landscape scales. However, resource homogenization might lead to poor and generalist pollinator communities, where functionally specialized interactions are lost. This study highlights the importance of including different scales to understand the effects of global change on pollination service through changes in resource diversity.

High flower richness and abundance decrease pollen transfer on individual plants in road verges but increase it in adjacent fields in intensively managed agroecosystems

Road verges can facilitate the movement of pollinators and pollen in intensively managed agroecosystems, reducing the negative impacts of fragmentation (i.e., isolation of wild pollinator communities) and enhancing the pollination service provided to wild plants. To assess the role of road verges in sustaining the pollination service to wild plants, we studied gardens consisting of two plant species arranged within sixteen road verges and their adjacent fields during two consecutive seasons in the Argentine Pampas. We assessed the influence of attributes of road verges on pollination service at different scales: road verges width, species richness of flowering plant, and flower abundance (patch scale), crops and successional pastures (adjacent land use scale), and landscape heterogeneity (landscape scale). We measured the pollination service provided to two species of potted plants (Hirschfeldia incana and Lobularia maritima) in three different ways: visitation rate, conspecific and heterospecific pollen transfer to stigmas, and distance of pollen transfer from a fixed source. The number of conspecific and heterospecific pollen grains deposited on stigmas decreased with an increased abundance of floral units in associated road verges, which is caused by a dilution effect on individual plant pollination. Also, the pollen transfer into adjacent fields decreased with an increased abundance of floral units in the nearby road verges, which is caused by a decrease of pollen spillover into adjacent crop fields. The visitation rate within adjacent fields increased with higher flowering plant species richness in associated road verges. Also, the number of conspecific pollen grains in the road verges adjacent to successional pastures increased with higher flowering plant species richness in road verges, which results in a concentration effect of pollinator visits and pollen transfer into road verges. We conclude that managing flower abundance and increasing flowering plant species richness in road verges are crucial practices for maintaining the pollination service of entomophilous plants in intensively managed agroecosystems.

Fragmentation of forest-steppe predicts functional community composition of wild bee and wasp communities

Increased habitat fragmentation in natural areas is one of the causes of declining insect diversity and biomass globally. Wild bees and wasps and their ecosystem functions are not exceptions of the trend. To stop this trend, we need to increase our understanding of interactions between functional traits and the environment for better informing conservation and restoration. Therefore, we studied how habitat fragmentation (i.e., connectivity, fragment size) and flower availability (abundance and species richness) affect functional traits of wild bees and wasps. Forest‐steppe is a complex ecosystem ranging from far East of Asia to Eastern Central Europe, consisting of a mosaic of woody and herbaceous vegetation patches. We selected 30 natural forest-steppe fragments along a connectivity gradient in the Hungarian Great Plain region. The size of the selected fragments ranged between 0.16 and 6.88 ha. We collected wild bees and wasps with yellow pan traps. We selected four functional traits: social habit, body size, feeding preference, and nesting location and investigated them in relation to habitat connectivity, patch size, flower abundance and richness. We used RLQ ordination to analyse the pollinators' functional community composition. We found that habitat connectivity supported larger, eusocial and ground nesting wild bees. Fragment size was closely related to larvae feeding preference in both studied groups by positively affecting oligolectic bees and carnivore wasps. Additionally, higher abundance and species richness of flowers maintained polygolectic bees and solitary, ground-nesting wasps. In our study, we described for the first time the relationship between the functional traits and habitat fragmentation of wild bee and wasp communities in a natural forest-steppe habitat. Our findings suggest that improved knowledge about the response of functional traits of wild bee and wasp communities to habitat fragmentation will allow a better understanding and prediction of subsequent effects on ecosystem functioning. We conclude that a combination of large, high-quality and well-connected patches maintains specialist wild bee and wasp communities. • Habitat fragmentation predicts functional trait changes of pollinators. • Diverse flowers maintained polygolectic bees and solitary, ground-nesting wasps. • Large fragments positively affected oligolectic bees and carnivore wasps. • Well-connected fragments supported large, eusocial, and ground-nesting bees.