Wild Bee Diversity Research Articles

The role of wild bees and cavity-nesting wasps as ecological indicators of the last traditionally managed meadows in Eastern Europe.

The number of wild bees and cavity-nesting wasps is abundant in agricultural areas and they contribute significantly to ecosystem services. Due to their specialization in nesting sites and food sources, these groups are sensitive to habitat condition changes and they are therefore important indicators for environmental impact assessments. As semi-natural habitats are steadily declining and often understudied, their significance for research is increasingly recognized. During this research, the role of wild bee species and cavity-nesting Hymenopteran taxa as indicators was examined, along the unique combination of high nature value and traditional land use habitats in Eastern Europe, Transylvania. Transects and trap nests were used to test the diversity and abundance of wild bees and cavity-nesting Hymenopterans to identify possible differences between highly protected and less protected areas. The differences in taxonomic groups between the sites and the potential effects of landscape structure on wild bees and cavity-nesting Hymenopterans were also assessed. We detected a high diversity of wild bee species and a significant species replacement from one study year to another. Among the nest-building Hymenopteran taxa, the majority of nests was built by Trypoxylon sp. during both study years, with a stronger dominance in the second year. The different taxonomic groups of wild bees and cavity-nesting Hymenopterans showed differences in their habitat affinities. The majority of the sampled bumblebee species as well as Trypoxylon sp. had an affinity towards the study sites located within the highly protected study area. Altogether, we found different habitat preferences for different Hymenopteran groups (both wild bees and wasps) and conclude that these groups definitely have the potential to serve as indicators for differences in the intensity of land use.

Wild Bee Conservation in Viticulture: Effects of Semi-Natural Habitats, Organic Management, and Fungicide Reduction.

In agricultural landscapes, the removal of semi-natural habitats (SNH) and the intensive use of pesticides contribute to declines of biodiversity, including crop pollinators such as bees (Hymenoptera: Apoidea). However, effects of pesticide use and landscape characteristics on bees have rarely been studied together. In this study, we investigated how SNH in the surrounding landscape, organic and conventional management, and the reduction of fungicides affect wild bee diversity in 32 vineyards in southwest Germany. We used yellow pan traps to sample bees in a crossed design of management (organic vs. conventional) and fungicide use (reduced in fungus-resistant grape varieties vs. regular) along a gradient with increasing proportions of SNH in the surrounding landscape. Higher proportions of SNH influenced species composition of bees and increased the abundance and richness of above-ground-nesting species. Organic vineyards had a 49% higher abundance of bees compared to conventional vineyards. The reduction of fungicides did not affect bee diversity nor abundance. The absence of a response to fungicide intensity suggests that the benefit of organically managed vineyards to wild bees was through differences in their vegetation management, which is in line with the positive response of bees to SNH in the surrounding landscape. Synthesis and applications: Our study underlines that the local provision of diverse vegetation in vineyards and the landscape-scale provision of suitable SNH are key factors for wild bee conservation in viticulture.

Are parks as favourable habitats for wild bees as wastelands in watercourse valleys of a large city?

Because of the growing population density and rate of urban development, the question of biodiversity conservation in cities and towns is increasingly important. In general, urban environments provide attractive habitats for a diversity of wild bees, but different types of urban habitats can have different effects on these pollinating insects. In this study, we compared the attractiveness of two different urban habitat types – parks (10 sites) and wastelands (10 sites) located in river and canal valleys in Bydgoszcz (northern Poland) – with respect to abundance, species richness, species composition, and functional trait composition of wild bees. We hypothesized that urban wastelands are more attractive to wild bees than urban parks are. Urban wastelands were characterized by higher abundance and species richness of wild bees compared to urban parks. When habitat type was the only predictor, nonlinearity of wild bee abundance and species richness was significant exclusively for wastelands. Overall, both wild bee abundance and species richness depended on the percentage of total bee food plant coverage, regardless of habitat type. Wild bee community composition also responded significantly to the percentage of total bee food plant coverage. Local and landscape features of the green spaces affected the functional traits of the wild bees recorded there. These findings reveal that formal green spaces, such as managed parks, are not sufficient to conserve wild bee resources in urban environments in river and canal valleys. In contrast, high-quality informal urban green spaces, such as urban wastelands, can promote abundant and rich wild bee communities. Thus it is crucial to strive for appreciation and protection of this persistently overlooked category of urban green spaces.

Local factors influence the wild bee functional community at the urban-forest interface

IntroductionUrban forests provide necessary habitat for many forest-associated bee species amidst development and fragmentation. These forest fragments provide a variety of important floral and non-floral resources for bees that encompass a diversity of functional guilds characterized by size, diet breadth, nesting, sociality, origin, and seasonality. The relative importance of forest edge vs. interior habitats to these organisms is not well understood.MethodsHere, we compare bee communities between forest edge and interior locations at eight locations in Athens, GA, USA. We also explore the effects of stand structure, tree composition, ground cover type, and the presence of snags and downed wood on these organisms.ResultsWe found bee abundance and richness to be higher at the forest edge than interior with distinct community compositions at both locations. Canopy cover, invasive shrub cover, ground cover, and tree diversity influenced the observed community composition. We also determined that the most impactful functional traits influencing bee community structure in urban forest fragments were nesting substrate, origin (native or exotic to North America), sociality, and diet breadth.DiscussionOur findings will help establish the effects of local forest characteristics on the community composition, diversity, and abundance of wild bees and further our knowledge of the conservation value of urban forests for preserving wild bee communities.

Evaluation of wild bee diversity in fruit orchards within the Ba Den mountain area, Tay Ninh Province, Vietnam

Wild bees are commonly found and play a vital role in pollinating various crops. Unfortunately, the number of wild bee species is experiencing a steep decline, attributed to deforestation, the application of agricultural pesticides, escalating environmental pollution, and the spread of urbanization. Hence, research on bee diversity is essential for the protection of these crucial pollinators. The objective of this study was to conduct a comparative assessment of wild bee richness and abundance within fruit orchards. From February to May 2023, the study was conducted in the Ba Den mountain area of Tay Ninh Province, encompassing Tay Ninh City and the Duong Minh Chau district. Malaise traps were used to collect bee samples during the flowering season of the fruit orchards. Simultaneously, the flowering plants in the surrounding vicinity were meticulously identified and observed. The composition of wild bees was determined and compared between orchards. In total, 836 bee specimens belonging to 27 distinct wild bee species spanning three families, along with 30 flowering plant species across 17 families, were recorded. It was found that the Apidae family stood out as the most abundant and diverse group within the wild bee population. Additionally, the abundance of Ceratina smaragdula was noted across three orchards. Within the fruit orchards, the Fabaceae and Asteraceae families emerged as widely prevalent among flowering plants. Importantly, the first fruit orchard exhibited a greater richness and abundance of wild bees, coupled with a higher count of flowering plant species, in comparison to the other fruit orchards. The amassed data in this study, which encompasses insights into biodiversity, distribution patterns, and variations across different orchards, not only aids in the preservation of these pivotal pollinators but also lends essential support to the realm of agricultural production.

Urbanisation impacts the diversity, coloration, and body size of wild bees in a Mediterranean city

Urbanisation impacts the diversity, coloration, and body size of wild bees in a Mediterranean city

Impact Of Beekeeping On The Wild Bee Diversity In Northern Cote D'Ivoire (West Africa)

In Cote d’Ivoire, beekeeping takes an important place among the major economic activities. It contributes to improve the population livelihoods thanks to its derived products which are honey, propolis, wax and royal jelly. However, the installation of honey bee hives could put pressure on wild bee species which are live often alone (solitary bees). However, these wild bees are excellent pollinators of cultivated and wild plants. Our study aimed to assess the effect of honey bee hives on the diversity of wild bee. The methodology approach consisted to capture bees in three different plots within the forest fragment of the university Peleforo Gon Coulibaly. The first plot was located near the apiary containing ten hives. The two other plots, far to the apiary, were located to 200 m and 400 m from the first plot, respectively. Bees were captured once a month for three months using pan traps (UV - blue, yellow and white). A total of 17 bee species belonging to three families (Apidae, Megachilidae and Halictidae) were identified. The furthest plot from the apiary was the most diverse (H’ = 2.49) and that near the apiary was the least diverse (H’ = 0.11). Only, two wild bee species, Hypotrigona sp and Thrinchostoma petersi, persisted inside the plot near the apiary where honey bee was most abundant. The furthest plots from the apiary seems to have the highest diversity of wild bees. These findings are very relevant because they can play an essential role in the policies of wild bee communities’ conservation and in the beekeeping activities management in our regions.

Bee-diverse habitats positively affect seed set in wild plant species

IntroductionInteractions between flowering plants and visiting wild bees are crucial for ensuring pollination and subsequent plant reproductive success. However, bee diversity in an area has rarely been recorded in relation to seed set in native plants. In this project, we investigated the effect of local wild bee communities on seed set in four common wild plant species.MethodsPotted plants of Centaurea jacea, Cichorium intybus, Sinapis arvensis, and Salvia pratensis were placed for pollination experiments, in two distinct habitat types that we expected to show distinct bee communities, namely near-natural grassland and perennial wild flower strips, in Germany.ResultsOur results showed that near-natural grassland had a higher bee species richness and an increased seed set compared with flower strips that displayed a higher bee abundance in most study locations. Although we found effects of bee diversity on seed set, we did not detect a significant effect of bee abundance. Furthermore, the seed set in response to wild bee diversity differed across the plant species.DiscussionWe conclude that bee-friendly habitats ensure a high seed set in wild plants, but that the impact varies between different plant species.

Assessing the biodiversity and the impact of pollinators on carob production.

As the current climate crisis intensifies, drought resistant crops are becoming more important due to their ability to withstand the increasingly hotter and drier summers. Such crops are valuable for pollinators as they provide food resources for wild and managed species. The carob tree (Ceratonia siliqua L.) represents an example of a heat- and drought- resistant crop, able to grow in dry areas with practically no inputs. The current study assessed over two growing seasons the diversity of wild bees and other pollinators relying on carob flowers, as well as the contribution of animal pollination to carob production. Carob flowers were subjected to two treatments: Open pollination, where inflorescences were left untreated, and wind pollination, where inflorescences were bagged in a mesh during blooming. Weekly observations during blooming showed that Apis mellifera was the most frequent floral visitor followed by wild bees and wasps. Carob flowers were visited by at least 10 different wild bee species. Open-pollinated flowers produced significantly more pods, with the benefit ranging from 4 to 16 times higher production, depending on the region. Open pollination led to pods with greater weight, length and number of seeds compared to pods derived from wind pollination. The results of the current study highlight the importance of animal pollination to carob production, as well as the significance of carob trees to wild bee conservation.

Global taxonomic, functional, and phylogenetic diversity of bees in apple orchards

An essential prerequisite to safeguard pollinator species is characterisation of the multifaceted diversity of crop pollinators and identification of the drivers of pollinator community changes across biogeographical gradients. The extent to which intensive agriculture is associated with the homogenisation of biological communities at large spatial scales remains poorly understood. In this study, we investigated diversity drivers for 644 bee species/morphospecies in 177 commercial apple orchards across 33 countries and four global biogeographical biomes. Our findings reveal significant taxonomic dissimilarity among biogeographical zones. Interestingly, despite this dissimilarity, species from different zones share similar higher-level phylogenetic groups and similar ecological and behavioural traits (i.e. functional traits), likely due to habitat filtering caused by perennial monoculture systems managed intensively for crop production. Honey bee species dominated orchard communities, while other managed/manageable and wild species were collected in lower numbers. Moreover, the presence of herbaceous, uncultivated open areas and organic management practices were associated with increased wild bee diversity. Overall, our study sheds light on the importance of large-scale analyses contributing to the emerging fields of functional and phylogenetic diversity, which can be related to ecosystem function to promote biodiversity as a key asset in agroecosystems in the face of global change pressures.

Both Landsat‐ and LiDAR‐derived measures predict forest bee response to large‐scale wildfire

AbstractLarge‐scale disturbances such as wildfire can have profound impacts on the composition, structure, and functioning of ecosystems. Bees are critical pollinators in natural settings and often respond positively to wildfires, particularly in forests where wildfire leads to more open conditions and increased floral resources. The use of Light Detection and Ranging (LiDAR) provides opportunities for quantifying habitat features across large spatial scales and is increasingly available to scientists and land managers for post‐fire habitat assessment. We evaluated the extent to which LiDAR‐derived forest structure measurements can predict forest bee communities after a large, mixed‐severity fire. We hypothesized that LiDAR measurements linked to post‐fire forest structure would improve our ability to predict bee abundance and species richness when compared to satellite‐based maps of burn severity. To test this hypothesis, we sampled wild bee communities within the Douglas Fire Complex in southwestern Oregon, USA. We then used LiDAR and Landsat data to quantify forest structure and burn severity, respectively, across bee sampling locations. We found that the LiDAR forest structure model was the best predictor of abundance, whereas the Landsat burn severity model had better predictive ability for species richness. Furthermore, the Landsat burn severity model was better at predicting the presence and species richness of bumble bees (Bombus spp.), an ecologically distinct and economically important group within the Pacific Northwest. We posit that the divergent responses of the two modeling approaches are due to distinct responses by bee taxa to variation in forest structure as mediated by wildfire, with bumble bees in particular depending on closed‐canopy forest for some portions of their life cycle. Our study demonstrates that LiDAR data can provide information regarding the drivers of bee abundance in post‐wildfire conifer forest, and that both remote sensing approaches are useful for predicting components of wild bee diversity after large‐scale wildfire.

Biodiversity and pollination benefits trade off against profit in an intensive farming system.

Agricultural expansion and intensification have boosted global food production but have come at the cost of environmental degradation and biodiversity loss. Biodiversity-friendly farming that boosts ecosystem services, such as pollination and natural pest control, is widely being advocated to maintain and improve agricultural productivity while safeguarding biodiversity. A vast body of evidence showing the agronomic benefits of enhanced ecosystem service delivery represent important incentives to adopt practices enhancing biodiversity. However, the costs of biodiversity-friendly management are rarely taken into account and may represent a major barrier impeding uptake by farmers. Whether and how biodiversity conservation, ecosystem service delivery, and farm profit can go hand in hand is unknown. Here, we quantify the ecological, agronomic, and net economic benefits of biodiversity-friendly farming in an intensive grassland-sunflower system in Southwest France. We found that reducing land-use intensity on agricultural grasslands drastically enhances flower availability and wild bee diversity, including rare species. Biodiversity-friendly management on grasslands furthermore resulted in an up to 17% higher revenue on neighboring sunflower fields through positive effects on pollination service delivery. However, the opportunity costs of reduced grassland forage yields consistently exceeded the economic benefits of enhanced sunflower pollination. Our results highlight that profitability is often a key constraint hampering adoption of biodiversity-based farming and uptake critically depends on society's willingness to pay for associated delivery of public goods such as biodiversity.

Contrasting effects of wooded and herbaceous semi-natural habitats on supporting wild bee diversity

The use of pesticides and the lack of resources caused by the simplification of landscapes are often cited as the main drivers of the loss of wild bees. Landscape complexity has been shown to interact with local pesticide use in studies of the effect of these factors on the abundance and diversity of insects. But, to date, few studies have simultaneously investigated local and landscape effects on wild bees using more precise descriptors of the landscape and of farming practices. The aim of the present study was thus to disentangle the effects of landscape composition and farming practices on the taxonomic and functional diversity of wild bees and their possible consequences for pollination potential. We analysed a dataset of 107 crops at whose edges wild bees were captured between 2013 and 2019. Pesticide treatments of each crop were recorded throughout the year. At the landscape level, the proportions of different types of land use were calculated in a circle with a radius of 500 m. We caught 1536 wild bees belonging to 86 species and, using generalized mixed modelling, found that the number of insecticide applications had a negative effect on wild bee abundance and richness, while forest cover within a 500-m radius had a positive effect on wild bees whatever the farming practices. However, we also showed that the effect of the proportion of permanent grasslands on taxonomic and functional diversity of wild bees differed depending on the use of fungicides in the field. Finally, we found a negative effect of the number of herbicide applications on pollination potential. This study advances our understanding of the contrasting but complementary roles of diverse semi-natural habitats in agricultural landscapes in supporting wild bee diversity and which, under certain conditions, may buffer the detrimental consequences of pesticide use.

The impact of heavy metal pollution on wild bee communities in smallholder farmlands

Wild bees provide important pollination services, but they face numerous stressors that threaten them and their ecosystem services. Wild bees can be exposed to heavy metal pollution through the consumption of nectar, pollen, and water, which might cause bee decline. While some studies have measured heavy metal concentrations in honeybees, few studies have monitored heavy metal concentrations in wild bees or explored their potential effects on wild bee communities. To investigate the impact of heavy metal pollution on wild bee communities, heavy metal concentrations, including vanadium (V), chromium (Cr), nickel (Ni), cadmium (Cd), Zinc (Zn) and lead (Pb) in multiple wild bee species were measured. Multiple wild bee species, including: Xylocopa tranquabaroroum, Eucera floralia, Apis cerana, and small bee mixtures (representing multiple small wild bee species) were sampled from 18 sites in Quzhou, Zhejiang Province, China. The findings demonstrated that there were significant differences in heavy metal concentrations among different bee species. The concentrations of V, Zn, Cd, and Pb in X. tranquabaroroum, the largest bee species in this study, were lower than that in the other three sample groups. Furthermore, there were significant negative correlations between heavy metal pollution and wild bee diversity and species richness, but not with abundance. Particularly, there was no significant relationship between heavy metal pollution and the abundance of small bees. Given these worrying findings, monitoring multiple heavy metals in wild bees should be conducted for protecting wild bee diversity and securing their pollination services.

Spatial mismatch between wild bee diversity hotspots and protected areas.

Wild bees are critical for multiple ecosystem functions but are currently threatened. Understanding the determinants of the spatial distribution of wild bee diversity is a major research gap for their conservation. We modeled wild bee α and β taxonomic and functional diversity in Switzerland to uncover countrywide diversity patterns and determine the extent to which they provide complementary information, assess the importance of the different drivers structuring wild bee diversity, identify hotspots of wild bee diversity, and determine the overlap between diversity hotspots and the network of protected areas. We used site-level occurrence and trait data from 547 wild bee species across 3343 plots and calculated community attributes, including taxonomic diversity metrics, community mean trait values, and functional diversity metrics. We modeled their distribution with predictors describing gradients of climate, resource availability (vegetation), and anthropogenic influence (i.e., land-use types and beekeeping intensity). Wild bee diversity changed along gradients of climate and resource availability; high-elevation areas had lower functional and taxonomic α diversity, and xeric areas harbored more diverse bee communities. Functional and taxonomic β diversities diverged from this pattern, with high elevations hosting unique species and trait combinations. The proportion of diversity hotspots included in protected areas depended on the biodiversity facet, but most diversity hotspots occurred in unprotected land. Climate and resource availability gradients drove spatial patterns of wild bee diversity, resulting in lower overall diversity at higher elevations, but simultaneously greater taxonomic and functional uniqueness. This spatial mismatch among distinct biodiversity facets and the degree of overlap with protected areas is a challenge to wild bee conservation, especially in the face of global change, and calls for better integrating unprotected land. The application of spatial predictive models represents a valuable tool to aid the future development of protected areas and achieve wild bee conservation goals.

Environmental variables and species traits as drivers of wild bee pollination in intensive agroecosystems—A metabarcoding approach

AbstractWild bees are known to be efficient pollinators of wild plants and cultivated crops and they are essential ecosystem service providers. However, wild bee populations have been suffering from significant declines in the last decades mainly due to the use of agrochemicals. Within this framework, we aimed to characterize wild bees' pollination spectrum (i.e., the community of pollinated flowering plants) in intensive agroecosystems, and describe the environmental variables and wild bee species traits influencing the pollination. To do this, we conducted metabarcoding analyses of pollen loads from wild bees collected in sunflower crops in the French region of Nouvelle‐Aquitaine. Our study revealed that wild bees visited flowering plants corresponding to 231 different operational taxonomic units, classified into 38 families of which Asteraceae, Brassicaceae, and Apiaceae were the most visited and more than 90% of the visited taxa turned out to be wildflowers. We also analyzed the potential effect of environmental variables and wild bee species traits in governing their choice of pollinated plants. The community composition of pollinated plants varied depending on the flowering stages of the sunflower and the farming system. Our results also show that pollination niche breadth (alpha diversity) varied depending on the flowering stages of the sunflower but was not different between organic and conventional farming systems. Regarding wild bee species traits, the community composition of pollinated plants varied in relation to wild bees' body sizes and sociality levels. Our results are consistent with previous studies, suggesting that solitary bees are more specialist when it comes to flower selection than social bees, which are more generalist. The metabarcoding of pollen loads enabled us to draw a global picture of plant–wild bee interactions in an intensive agroecosystem. Our findings support the hypothesis that a higher diversity of weeds may increase wild bee diversity in intensive agroecosystems.

Cascading effects of management and landscape on insect pollinators, pollination services and yield in apple orchards

Recent insect pollinator declines, mainly due to the expansion and intensification of agricultural land use, are jeopardizing ecosystem service provisioning in agroecosystems. Organic farming has been suggested as a biodiversity-friendly alternative to conventional farming, but additional insights evaluating its effectiveness in perennial cropping systems are needed. Here, we provide a comprehensive analysis of local and landscape effects on the provided pollination services and yield in apple crops. We first used mixed models to disentangle effects of agricultural management and landscape effects on both taxonomic and functional diversity of wild bees and hoverflies during bloom in both organic and integrated pest management (IPM) apple orchards in Belgium, and then compared these biodiversity indicators with semi-natural grasslands as a benchmark. Next, we applied piecewise structural equation modeling to quantify the direct and indirect effects of orchard management type and landscape on fruit set, seed set and ultimately on crop yield. Orchards, regardless of their type of management, hosted lower taxonomic and functional pollinator diversity compared to the semi-natural benchmark. Yet, pollinator abundance and diversity were higher in orchard edges and increased with small-scale landscape diversity, which was positively associated with the presence of semi-natural habitat, as well as arable and urban land. Investigating the cascading effects on apple yield, we found that yield levels were not shaped by the observed pollinator diversity or by the measured pollination services, but were lower in organic orchards. Overall, we conclude that apple yield was likely not pollinator limited in our study system, but that conserving and restoring semi-natural habitats, maintaining and expanding orchard edges through reducing field sizes and promoting landscape diversity are the most promising avenues for pollinator conservation in orchard landscapes.

European bee diversity: Taxonomic and phylogenetic patterns

AbstractAimWild bees still face striking shortfalls in knowledge of biodiversity in key regions of the world. This includes Europe, where despite a long tradition of data gathering, the continental scale distribution patterns of wild bees have not been systematically analysed to date. This study aims to characterise large‐scale biodiversity patterns to: (i) understand spatial–temporal heterogeneity in large‐scale databases, (ii) locate genuine diversity hotspots and their relationship with biogeographical patterns or habitats of interests and (iii) identify understudied species and areas to further design conservation actions for most at risk species in key regions.LocationEurope.TaxonBees.MethodsWe present a continental and standardised study of bee taxonomic and phylogenetic diversity patterns in Europe, using a large compilation of occurrence records of nearly three million validated occurrence records for 1515 wild bee species.ResultsSouthern and eastern Europe suffer from the largest gaps in data availability while northern and western regions benefit from better historical coverage. Our models show that higher wild bee diversity in Europe is hosted in xeric, warm areas, as highlighted by a clear latitudinal gradient. However, phylogenetic diversity is predicted to be more homogenous across Europe than taxonomic diversity, suggesting that policies and strategies targeted to protect species richness may differ from those targeting greater phylogenetic diversity.Main conclusionsThis study represents a significant advance in the characterisation of wild bee distribution patterns across Europe and is an important stepping stone towards the design of more targeted survey efforts and conservation actions of this key group of pollinators. This, in turn, will provide the data necessary to improve the spatiotemporal coverage in a context of ongoing and future Europe‐wide monitoring schemes, to ultimately develop cost‐effective, coordinated and evidence‐based conservation actions and tailored habitat management actions that can be implemented on a smaller scale.

Diversity of bees in two crops in an agroforestry ecosystem in Kangsabati South Forest Division, Purulia, West Bengal, India

The investigation study assesses the diversity of bees in Brinjal Solanum melongena L. and Ridge Gourd Luffa acutangula L. crop field from agroforestry ecosystem in South Kangsabati Forest Division, India. The study was carried out in May 2021 to May 2022 that based on transect, focal observation and pan trap samplings. A total of 1,085 individuals were identified during the field work, belonging to three family seven genera (Apis, Tetragonula, Xylocopa, Ceratina, Amegelia, Nomia, and Megachile) and seventeen species, the non Apis bees (63.78%) were most abundant than Apis bees (36.22%). In brinjal, Shannon diversity index of bees is 2.12 and Shannon evenness index is 0.35, whereas, Shannon diversity index in ridge gourd was 1.94 and Shannon evenness index is 0.3. The observations signify greater diversity and population of wild bees. The natural habitat close to agricultural land helps to sustain the diversity and population of wild bees, which enhance the crop quality and yield.

Large Remaining Forest Habitat Patches Help Preserve Wild Bee Diversity in Cultivated Blueberry Bush

Global declines in wild and managed bee populations represent a major concern for the agricultural industry. Such declines result, in part, from the loss of natural and semi-natural habitats in and around agricultural ecosystems. However, remaining forest patches in heavily modified landscapes represent nesting habitats that may be crucial to preserving wild bees and their services. Because wild bees are the main pollinators of fruit crops, preserving potential nesting habitats might be particularly important for the crops’ yield and profitability. Here, we assessed whether the abundance and richness of visiting wild bees in blueberry crops relates to the amount of surrounding forest cover and if so, whether those relationships varied with spatial scale. Specifically, we sampled wild bee communities in 18 blueberry fields during the blooming period in Montérégie, Quebec, Canada, where sampling consisted of pan trap triplets and direct observation of flower visitors on blueberry bushes. Then, we quantified the proportion of forest in radii of 0.5 km, 1 km, and 2 km around each field. Wild bee abundance was positively related to the proportion of forest habitat surrounding the crop field, but the relationship for wild bee richness was less clear. Moreover, these relationships were strongest at 1 and 2 km radii of measured land cover. Overall, pollinator diversity was highest when at least 30% of the surrounding landscape consisted of forest patches, representing a total area of at least 1 km2. Our results suggest that preserving large habitat patches in agricultural landscapes can help prevent further decline in wild bee diversity while maximizing pollination services to fruit crops.