Floral Availability Research Articles

The role of landscape factors in shaping bumble bee pathogen loads across regions of the eastern Nearctic

Abstract Pathogens and parasites are drivers of declines in bumble bees. Their levels can be influenced by numerous abiotic and biotic factors, thus managing disease in these bees requires understanding the relative impact of these factors on pathogen loads. We evaluated loads of black queen cell virus (BQCV) and deformed wing virus in bumble bees (Bombus impatiens) and honey bees (Apis mellifera), and loads of parasites Vairimorpha bombi and Crithidia bombi in B. impatiens, from sites varying in habitat type and quality across North Carolina, USA. Pathogen loads were assessed against metrics for land cover, floral quality, bee diversity and weather. Results were compared against similar data from Pennsylvania, USA, and other landscape studies on bumble bees in North America. Spatial variation in pathogen loads was lower in bumble bees in North Carolina than in Pennsylvania, which reduced the power to detect landscape effects. For example, Crithidia was fairly ubiquitous and Vairimorpha was not detected. Data from both states revealed that developed land and honey bees were most consistently positively correlated with viral loads, especially for BQCV, whereas forest and nesting habitat availability were often negatively correlated with loads. Multivariate models only supported a positive relationship between summer floral resources and BQCV loads in North Carolina bumble bees. Together with the broader literature, these data indicate that levels of developed land and honey bees are most associated with increased pathogen loads while floral availability and bee community composition show more context‐dependent effects.

Antioxidant Activity, Physicochemical and Sensory Properties of Stingless Bee Honey from Australia.

This study reports on the physicochemical and sensory attributes, total phenolic content, and antioxidant activity of 36 honey samples produced by two different stingless bee species (Tetragonula carbonaria and Tetragonula hockingsi) from Australia. The findings reveal moisture content across all samples ranges from 24.9% to 30.8% (w/w), electrical conductivity from 1.02 to 2.15 mS/cm, pH levels between 3.57 and 6.54, soluble solids from 69.2 to 75.1 °Brix, trehalulose concentrations from 6.20 to 38.2 g/100 g, fructose levels from 7.79 to 33.4 g/100 g, and glucose content from 3.36 to 26.8 g/100 g. Sucrose was undetectable in all investigated samples. In a sensory analysis involving 30 participants, Australian stingless bee honey was perceived as having a more pronounced sourness compared with New Zealand Manuka honey. The study reveals considerable variability in the composition of Australian stingless bee honey, influenced by factors such as floral availability, geographical origin, and time of harvest. It also demonstrates the presence of phenolic compounds and antioxidant activity in stingless bee honey, underlining their potential as a natural source of antioxidants. All investigated samples contain trehalulose, which supports the findings of other recent studies that propose this unusual disaccharide as a marker compound of stingless bee honey.

Geographic drivers more important than landscape composition in predicting bee beta diversity and community structure

AbstractThe importance of microhabitat traits such as floral availability is well known; however, forest bee spatial dynamics have been variably studied across local to broad geographic scales. Past literature suggests that landscape factors from proximate to distal are important in determining forest bee community metrics, including richness, abundance, and taxonomic composition. Leveraging the interest and assistance of citizen science volunteers, we employed standard bee bowl trap transects across Maryland, Delaware, northern Virginia, and the District of Columbia and identified correlations between bee community composition, local and regional land cover, and broader geospatial patterns. We also identified the partial contributions of both specific species and sampling sites to total beta diversity. Various land cover metrics were significantly related to bee community structure, with bee abundance positively and negatively correlated with forest and wetland cover, respectively. In general, land cover metrics within 1000‐m buffer exhibited stronger correlations with bee communities; however, broader geographic variation, using Cartesian coordinates north and east as indices, was most significantly correlated with the bee community. Specifically, bee communities were less rich in the east and south of the study area. We also identified similar correlations with the bee community as categorized by both trophic and nesting behaviors, with both geographic northing and easting proving to be most strongly correlated with the forest bee community. Results of beta diversity and cluster analyses showed that the most species‐depauperate sites exhibited the highest contributions to beta diversity and that species‐poor sites consisted of a reduced subset of the greater community. Our results show that successful bee conservation must consider, beyond local‐scale resource availability, broad geospatial considerations and forest habitat connectivity across political and administrative boundaries.

Environmental Effects on Bee Microbiota.

Anthropogenic activities and increased land use, which include industrialization, agriculture and urbanization, directly affect pollinators by changing habitats and floral availability, and indirectly by influencing their microbial composition and diversity. Bees form vital symbioses with their microbiota, relying on microorganisms to perform physiological functions and aid in immunity. As altered environments and climate threaten bees and their microbiota, characterizing the microbiome and its complex relationships with its host offers insights into understanding bee health. This review summarizes the role of sociality in microbiota establishment, as well as examines if such factors result in increased susceptibility to altered microbiota due to environmental changes. We characterize the role of geographic distribution, temperature, precipitation, floral resources, agriculture, and urbanization on bee microbiota. Bee microbiota are affected by altered surroundings regardless of sociality. Solitary bees that predominantly acquire their microbiota through the environment are particularly sensitive to such effects. However, the microbiota of obligately eusocial bees are also impacted by environmental changes despite typically well conserved and socially inherited microbiota. We provide an overview of the role of microbiota in plant-pollinator relationships and how bee microbiota play a larger role in urban ecology, offering microbial connections between animals, humans, and the environment. Understanding bee microbiota presents opportunities for sustainable land use restoration and aiding in wildlife conservation.

Native and introduced pollinators vary in their seasonal floral resource visitation and selection between native and exotic plant species

Abstract Anthropogenic pressures on native ecosystems have resulted in numerous functional and compositional changes, creating novel ecosystems with new interactions between native and exotic species. How native species utilize these resources is crucial for their management in altered landscapes and the promotion of their essential ecosystem services. We compared seasonal floral selection between European honey bees and their most phylogenetically similar native component in our study region, bumble bees, in North American grasslands with high densities of exotic plant species. Additionally, we determined whether floral species richness, total flowering density, native floral density or exotic floral density best explained the abundance of both groups. Selection analyses revealed that honey bees and native bumble bees differed in selection between native and non‐native floral resource availability, with any significant selection of honey bees being for exotic plants while native bumble bees selected for native plants. Native forb presence and floral richness best explained the variation in bumble bee abundance, while honey bee abundance was associated with flowering densities in the early and mid‐seasons and floral richness in both the early and late seasons. Despite their generalist diets, we emphasize the importance of native floral availability for bumble bee foraging in novel grassland landscapes and the importance of exotic plants to support honey bee production. Synthesis and applications. Our results indicate that pollinator forage management should differ for non‐native and native species, despite morphological and life‐history similarities. However, greater floral diversity provides a common management focus that can benefit honey bees and bumble bees in particular seasonal periods. Our results suggest that management actions promoting resource diversity can benefit functionally different species. In grasslands, implementing disturbance processes that can favour floral expression (e.g. fire; grazing) can support bumble bees of conservation concern and agriculturally important bees simultaneously.

Bumble bee banquet: Genus‐ and species‐level floral selection by MidwesternBombus

AbstractRegionally specific flower preference data are needed to optimize conservation habitat plantings for at‐risk pollinators such as bumble bees (Bombusspp.). Current tools for selecting flowers for plantings rely on raw bee flower visits, which can be biased toward abundant flowers. To assist in planning habitat enhancements for bumble bees, we quantified genus‐ and species‐level floral preferences using a selection index that accounts for floral availability. Through 477 h of observation in Ohio, USA during the summers of 2017 and 2018, we recorded 22,999 observations of eightBombusspecies visiting 96 flowering plant taxa. As a genus,Bombusselected flowers nonrandomly; the most strongly preferred plants includedAsclepiasspp.,Cirsiumspp., Convolvulaceae,Dipsacusspp.,Echinacea purpurea,Monarda fistulosa,Penstemon digitalis, andSilphiumspp. Only a few Fabaceae were highly selected (Baptisiaspp.,Trifolium pratense, andViciaspp.), while some were preferred only during their peak bloom (Securigera varia), and others were not preferred by bumble bees (T. hybridumandMelilotusspp.). Diets differed among habitats, and in restored meadows, bumble bees selected for native planted species such asMonarda fistulosa,Asclepias syriaca,Echinacea purpurea,Penstemon digitalis, andSilphiumspp. Diets and preferences shifted over the season, largely driven by changes in plant phenologies (e.g., in June,Penstemonwas strongly selected, in July,Asclepias, and in August,Verbena). For the three most commonBombus(B. impatiens,B. griseocollis, andB. bimaculatus), rarefaction analysis indicates that we were able to detect almost all plants in their summer diets. However, for five less common species, even our extensive sampling was insufficient to fully characterize their diets. The commonBombusspecies differed in their feeding niches, perhaps reducing interspecific competition. In contrast, we found high diet overlap between three rarer species—B. vagans,B. fervidus, andB. pensylvanicus, suggesting that these at‐risk species might benefit from different floral communities than would the common species. Five of eight species (including one that is currently under review for federal listing) most strongly preferred one or another non‐native plant, presenting managers with a conservation conundrum concerning how to balance the needs of bees with the preservation of native plants.

Temporal change in floral availability leads to periods of resource limitation and affects diet specificity in a generalist pollinator.

Generalist species are core components of ecological networks and crucial for the maintenance of biodiversity. Generalist species and networks are expected to be more resilient, and therefore understanding the dynamics of specialization and generalization in ecological networks is a key focus in a time of rapid global change. Whilst diet generalization is frequently studied, our understanding of how it changes over time is limited. Here we explore temporal variation in diet specificity in the honeybee (Apis mellifera), using pollen DNA metabarcoding of honey samples, through the foraging season, over two years. We find that, overall, honeybees are generalists that visit a wide range of plants, but there is temporal variation in the degree of specialization. Temporal specialization of honeybee colonies corresponds to periods of resource limitation, identified as a lack of honey stores. Honeybees experience a lack of preferred resources in June when switching from flowering trees in spring to shrubs and herbs in summer. Investigating temporal patterns in specialization can identify periods of resource limitation that may lead to species and network vulnerability. Diet specificity must therefore be explored at different temporal scales in order to fully understand species and network stability in the face of ecological change.

Anthropogenic effects on the body size of two neotropical orchid bees

To accommodate an ever-increasing human population, agriculture is rapidly intensifying at the expense of natural habitat, with negative and widely reported effects on biodiversity in general and on wild bee abundance and diversity in particular. Cities are similarly increasing in area, though the impact of urbanisation on wild bees is more equivocal and potentially positive in northern temperate regions. Yet agriculture and urbanisation both lead to the loss and alteration of natural habitat, its fragmentation, a potential reduction in floral availability, and warmer temperatures, factors thought to be drivers of wild bee decline. They have also been shown to be factors to which wild bee populations respond through morphological change. Body size is one such trait that, because of its relation to individual fitness, has received growing attention as a morphological feature that responds to human induced modification in land use. Here, we investigated the change in body size of two sympatric orchid bee species on the Yucatan Peninsula of Mexico in response to urbanization and agricultural intensification. By measuring 540 male individuals sampled from overall 24 sites, we found that Euglossa dilemma and Euglossa viridissima were on average smaller in urban and agricultural habitats than in natural ones. We discuss the potential role of reduced availability of resources in driving the observed body size shifts. Agricultural and urban land management in tropical regions might benefit wild bees if it encompassed the planting of flowering herbs and trees to enhance their conservation.

The impact of mass-flowering crops on bee pathogen dynamics.

Nearly two fifths of the Earth's land area is currently used for agriculture, substantially impacting the environment and ecosystems. Besides the direct impact through land use change, intensive agriculture can also have an indirect impact, for example by changing wildlife epidemiology. We review here the potential effects of mass-flowering crops (MFCs), which are rapidly expanding in global cropping area, on the epidemiology of known pathogens in bee pollinators. We bring together the fifty MFCs with largest global area harvested and give an overview of their pollination dependency as well as their impact on bee pollinators. When in bloom these crops provide an abundance of flowers, which can provide nutrition for bees and increase bee reproduction. After their short bloom peak, however, the fields turn into green deserts. These big changes in floral availability strongly affect the plant-pollinator network, which in turn affects the pathogen transmission network, mediated by shared flowers. We address this dual role of flowers provided by MFCs, serving as nutritional resources as well as pathogen transmission spots, and bring together the current knowledge to assess how MFCs could affect pathogen prevalence in bee pollinator communities.

Both landscape and local factors influence plant and hexapod communities of industrial water-abstraction sites.

At the landscape level, intensification of agriculture, fragmentation, and destruction of natural habitats are major causes of biodiversity loss that can be mitigated at small spatial scales. However, the complex relationships between human activities, landscapes, and biodiversity are poorly known. Yet, this knowledge could help private stakeholders managing seminatural areas to play a positive role in biodiversity conservation.We investigated how water‐abstraction sites could sustain species diversity in vascular‐plant communities and two taxonomic groups of insect communities in a fragmented agricultural landscape.Landscape‐scale variables (connectivity indices and surrounding levels of herbicide use), as well as site‐specific variables (soil type for vascular plants, floral availability for Rhopalocera, and low herbaceous cover for Orthoptera), were correlated to structural and functional metrics of species community diversity for these taxonomic groups, measured on 35 industrial sites in the Ile‐de‐France region in 2018–2019. Rhopalocera and Orthoptera consisted essentially of species with a high degree of dispersal and low specialization, able to reach the habitat patches of the fragmented landscape of the study area. Sandy soil harbored more diverse vascular‐plant communities. Plant diversity was correlated to a greater abundance of Rhopalocera and a lower richness of Orthoptera.Increasing landscape connectivity was related to higher abundance of plants and Rhopalocera, and a higher evenness index for Orthoptera communities. Higher levels of herbicide use were related to a decrease in the biodiversity of plants and Rhopalocera abundance. High levels of herbicide favored high‐dispersal generalist plants, while high levels of connectivity favored low‐dispersal plants. Specialist Orthoptera species were associated with low herbaceous cover and connectivity.Water‐abstraction sites are valuable seminatural habitats for biodiversity. Changing intensive agricultural practices in surrounding areas would better contribute to conserving and restoring biodiversity on these sites.

Impact of land use intensification and local features on plants and pollinators in Sub-Saharan smallholder farms

Sub-Saharan African crop production largely relies on smallholder farms, located both in urban and agricultural landscapes. In this context, the investigation of plant and pollinator diversity and their interactions is of primary importance since both these factors are threatened by land use intensification and the consequent loss of natural habitats. In this study, we evaluated for the first time how plant and pollinator insect assemblages and interactions in Sub-Saharan farming conditions are shaped by land use intensification. To do that, we complemented biodiversity field surveys in Northern Tanzania with a modern DNA metabarcoding approach to characterize the foraged plants and thus built networks describing plant-pollinator interactions at the individual insect level. Moreover, we coupled this information with quantitative traits of landscape composition and floral availability surrounding each farm. We found that pollinator richness decreased with increasing impervious and agricultural cover in the landscape, whereas the flower density at each farm correlated with pollinator richness. The intensification of agricultural land use and urbanization correlated with a higher foraging niche overlap among pollinators due to convergence of individuals’ flower visiting strategies. Furthermore, within farms, the higher availability of floral resources drove lower niche overlap among individuals, while a greater flower visitors abundance shaped higher generalization at the networks level (H2′), possibly due to increased competition. These mechanistic understandings leading to individuals’ foraging niche overlap and generalism at the network level, could imply stability of interactions and of the pollination ecosystem service. Our integrative survey proved that plant-pollinator systems are largely affected by land use intensification and by local factors in smallholder farms of Sub-Saharan Africa. Thus, policies promoting nature-based solutions, among which the introduction of more pollinator-friendly practices by smallholder farmers, could be effective in mitigating the intensification of both urban and rural landscapes in this region, as well as in similar Sub-Saharan contexts.

Designing sampling protocols for plant-pollinator interactions - timing, meteorology, flowering variations and failed captures matter

ABSTRACT Plant-pollinator interactions are key components of ecosystem functioning and are therefore increasingly studied. Of all the approaches used to estimate these interactions, the capture of pollinators along transects is a widely used and recognized method. However, specific choices of sampling design can strongly influence observations of insect visits and bias ecological interpretations. Yet, there is no agreement on the best transect design. Sampling intensity (number and length of transects) is an important element of these choices, but not the only one. Here we investigate the influence of three other facets of protocol choices that commonly arise when designing pollination transects: (i) the influence of sampling conditions that may interact with ecological variables of interest or bias observations, (ii) the measurement of floral availability frequency, and (iii) the management of insects observed but not captured. We quantified the importance of these three protocol choices using a large dataset of 720 plant-pollinator transects in protected wet meadows in France. Our results demonstrate the need to (i) cover a wide range of temporal and meteorological conditions for each site, and (ii) repeat the assessment of plot attractiveness for pollinators (a major covariate, usually simply derived from one-off vegetation surveys). In addition, we show that (iii) for analyses of visitation density among insect groups, failed insect captures should not be discarded but incorporated into the analyses. Overall, this research identifies three key choices in transect design and highlights their influence in our understanding of plant-pollinator interactions.

Intra-annual Spatiotemporal Dynamics of the Monarch Butterfly (Lepidoptera: Danaidae), Regal Fritillary (Lepidoptera: Heliconiinae), and Their Floral Resources in North Dakota, United States

AbstractMany butterflies in the United States, along with their nectar resources, are declining. Large-scale conservation planning can be challenging, however, when butterflies and their nectar sources exhibit disparate spatiotemporal dynamics. We initiated a multi-year survey on monarchs (Danaus plexippus), regal fritillaries (Speyeria idalia), and floral resources across North Dakota from 2017 to 2019 to understand resource use through space and time. We surveyed three sites in each county in North Dakota, twice a year for 3 yr, for a total of 954 site visits. Our objectives were to 1) identify important floral resources for monarchs and regal fritillaries, 2) determine intra-annual spatial and temporal distributions of the butterflies and their nectar sources, and 3) quantify how floral resources influenced butterfly abundance and interacted with spatiotemporal factors (latitude, longitude, and flight season). Milkweeds (Asclepias spp.), native thistles (Cirsium spp.), and blazing stars (Liatris spp.) were identified as particularly important nectar resources for monarchs and regal fritillaries; all plant and butterfly species exhibited unique spatiotemporal distributions. Monarch abundance at a site was positively related to the availability of flowering milkweeds, and regal fritillary abundance was positively related to the floral availability of native thistles and coneflowers (Echinacea spp.). These relationships were consistent across the spatial and temporal extent of our study, indicating that the butterfly–flower relationships we detected are maintained and relatively consistent across our study region and years. By accounting for spatiotemporal dynamics, we can help elucidate the persistence of butterfly-flower species interactions at large scales and inform conservation efforts for these threatened species.

Long-term data shows increasing dominance of Bombus terrestris with climate warming

While many bumblebee species decline due to climate and land-use changes, others cope well with contemporary conditions. One example is Bombus terrestris, which is common in intensively managed agricultural landscapes. During the 20th century its subgenus, which includes the B. lucorum complex (B. lucorum, B. cryptarum and B. magnus) came to dominate Scandinavian bumblebee communities, but the specific contribution of B. terrestris remains to be understood. Using historical data on males, we assessed how the relative abundances of B. terrestris and the B. lucorum complex changed over the past 150 years in southernmost Sweden. We tested if these changes differed between simplified and mixed landscapes and whether the relative abundance of B. terrestris was related to annual mean temperatures. Because floral availability has advanced as a response to climate change, we also tested if the activity period of males (estimated as catching date) has advanced and whether the advancement differs between taxa. The relative abundance of B. terrestris increased similarly in both landscapes, from 21% to 79% over the period, and this was largely explained by increasing temperature. Male activity period has advanced similarly in the two taxa, with 41 days between 1900 and 2015. Although the dominance of B. terrestris correlates clearly with annual mean temperature, it remains to disentangle why. It also remains to understand whether the success of B. terrestris occurs at the expense of other species or simply reflects that this species copes better with contemporary conditions.

Foraging preferences of the native stingless bee Melipona seminigra pernigra (Apidae: Meliponini) in campo rupestre on canga of Serra dos Carajás, southeastern Amazonia

Abstract: Honey pollen samples of Melipona seminigra pernigraMoure & Kerr 1950 sampled between 2017 and 2019 from experimental apiaries installed in campo rupestre on canga (CRC) vegetation of the Serra dos Carajás aimed to evaluated seasonal floral availability of undisturbed and mining-influenced areas. Around one hundred pollen types were identified mainly belonging to Fabaceae, Myrtaceae and Euphorbiaceae (31, 6 and 5 species, respectively). Mining area presented the highest pollen richness, almost twice those identified in the undisturbed areas. 80% of the pollen types are rare with concentrations ≤ 2,000 pollen grains/10 g, while the remaining were the most abundant, frequent and the primary bee sources. These latter correspond mostly to native plants species such as Tapirira guianensis Aubl., Protium spp., Aparisthmium cordatum (A.Juss.) Baill., Mimosa acutistipula var. ferrea Barneby, Periandra mediterranea (Vell.) Taub., Miconia spp., Pleroma carajasense K.Rocha, Myrcia splendens (Sw.) DC., Serjania spp. and Solanum crinitum Lam. All pollen types were identified during both seasons, but higher concentration values are related to the dry period (June-September). The statistical analysis of the pollen data indicated that there was no significant difference between undisturbed and mining-influenced areas, since primary bee sources of this study are widespread used in revegetation of mined areas.

Assessing the impacts of land use and climate interactions on beekeeping livelihoods in the Taita Hills, Kenya

ABSTRACT Beekeeping is commonly adopted as an additional livelihood activity that can help smallholder farmers diversify and enhance their livelihoods. However, it is unclear whether it is resilient to environmental shocks and stresses. This article investigates beekeepers’ experiences and perceptions about challenges to beekeeping in the Taita Hills Mountains, Kenya. Key findings demonstrated that beekeeping has the capacity to substantially increase household income, but there are several challenges which affect beekeeping’s sustainability considering predictions around climate and land use change. Bee population decline due to pesticide use was seen as a major challenge across the altitudinal range. In the highland areas deforestation, land use conflicts and cold weather were key issues; whereas in the lowlands water availability and the associated impacts on floral availability were the primary concerns of beekeepers.

The influence of floral resources and microclimate on pollinator visitation in an agro-ecosystem

As agriculture expands to meet the needs of a growing global population, natural ecosystems are threatened by deforestation and habitat fragmentation. Tropical agroforestry systems offer a sustainable alternative to traditional agriculture by providing food for production while also supporting biodiversity and ecosystem services. Previous studies have shown that these systems may even improve crop pollination, but the mechanisms of how these improvements occur are still poorly understood. Using coffee as a focal crop, we explored how microclimatic conditions affected nectar traits (sugar and caffeine concentration) important for pollinator visitation. We also studied how microclimate, floral traits, floral availability at the coffee plant level, availability of floral resources provided by other plant species in the agroecosystem (“neighborhood floral availability”), and the presence of other bees affected the amount of time bees spent foraging on coffee flowers and the proportion of coffee pollen carried on their bodies. We explored these factors using the two dominant coffee species farmed on Puerto Rico, Coffea canephora and C. arabica, under sun and shade management. We found that high nectar sugar concentration and temperature were important predictors of short floral visits (<15s), while increased numbers of bees and open coffee flowers were important predictors of longer floral visits (16–180 seconds). High nectar caffeine concentration was an important predictor of longer visits on C. arabica flowers while the opposite was observed for C. canephora flowers. For both species, high coffee floral availability was the main predicting factor for the proportion of coffee pollen on the bees’ bodies. Surprisingly, neither neighborhood floral availability nor the type of coffee plantation (agroforest/shade or sun) were important predictors of bee visitation. These results suggest non-coffee flowering plants in coffee plantations were neither competitors nor facilitators of coffee plants for pollinators. Additionally, most of the bees surveyed were carrying ≥80 % pollen from one species (C. arabica or C. canephora), likely resulting in little heterospecific pollen deposition between Coffea and non-Coffea flowers. Shade trees in coffee plantations do not detract from pollinator visitation to coffee flowers, suggesting that the provision of multiple ecological and wildlife conservation benefits by shade trees is not in conflict with a grower’s ability to maximize the benefits of insect pollination on fruit production.

Seasonality of bumblebee spillover between strawberry crops and adjacent pinewoods

In agricultural landscapes, differences in floral resources provided by crops compared with adjacent habitats promote the spillover of pollinators seeking to fulfil their feeding needs. These foraging patterns play an important role in both crop production and wild plant fitness. However, in classical observational studies, pollinator spillover patterns may be confounded by differences in pollinator phenologies and population sizes. To avoid these confounding effects, we quantified the combined effect of relative floral availability and season on pollinator spillover between strawberry crops and adjacent pinewoods by using commercial bumblebee colonies. We used 60 colonies that were placed in 6 open polytunnel strawberry crops and in 8 pinewoods adjacent to crops in landscapes with either low or high berry (mostly strawberry) crop cover. We repeated the experiment in winter and in spring to account for differences in flower resource availability. While strawberries were in bloom during the entire study period, wild flowering plants were scarce and abundant in winter and in spring, respectively. Spillover in crops was quantified as the percentage of bumblebee individuals that carried pollen from non-berry flowers, while spillover in pinewoods was quantified as the percentage of individuals that carried pollen from berry flowers. Overall, 526 bumblebees were collected. We found them carrying the pollen of 15 plant taxa in winter and 39 in spring, in accordance with seasonal floral availability. In crop colonies, around 30% of bumblebees spilled over into non-berry habitats in winter and 78% in spring, regardless of crop cover in the surrounding landscape. However, in pinewood colonies, we found an interaction effect between season and crop cover: even though on average 34% of bumblebees spilled over into berry crops, in winter it was almost twice in landscapes with high crop cover. Spillover patterns mainly mirrored seasonal changes in floral availability between habitats.

Coupling spatial pollination supply models with local demand mapping to support collaborative management of ecosystem services

ABSTRACT Mapping of ecosystem services (ES) is a powerful tool for communication and knowledge sharing about the implications of ecosystem management practices for human wellbeing. This research aimed to show the usefulness of ES mapping for decision-making by combining modelling of ES supply with ES demand mapping in a participatory process with the engagement of relevant stakeholders. We used the ESTIMAP-pollination model to map wild bee abundance and pollination supply in the Sudoeste Alentejano and Costa Vicentina Natural Park (PNSACV) in Portugal. The model was modified by adding a behavioural component that distributes pollinator visits according to floral availability. Balancing pollination supply with crop dependency levels allowed visualising potential areas of satisfied and unsatisfied demand and testing the effectiveness of ecosystem management interventions. The discussion of these results in two participatory workshops triggered the first collective debate about pollination in the PNSACV. This engagement enabled the development of a shared understanding about this ES and highlighted the role of ES maps as tools to support collaborative natural resources management.

Wild, native bees and managed honey bees benefit from similar agricultural land uses

Although both managed and unmanaged bees are important pollinators of crops and wild plants, efforts to address questions about landscapes that best support pollinators often focus on either wild pollinators or honey bees. This study examined if there was concordance between the success of wild bee communities and managed honey bee colonies at sites varying in floral availability and disturbance level in a predominantly agricultural landscape. We also determined which agricultural land uses best supported wild bee communities. The study area in the state of North Dakota in Northern Great Plains in North America is home to understudied native bee communities as well as over ¼ of U.S. commercial honey bee colonies during the summer months. There is an assumption that honey bees can do well in agricultural areas but that wild bees need natural areas to thrive. We compared wild bee community success with health and survival of managed honey bees (data obtained from a related study) at six apiary locations over three years. We examined wild bee communities and surrounding land uses at 18 locations, three of which were spatially associated with each of six apiary locations. Wild bee abundance and species diversity were positively correlated with honey production, a measure of honey bee success, indicating that locations supporting successful honey bee colonies also supported successful wild bee communities. Grasslands, bee-forage crops, wooded areas, and wetlands were associated with increased abundance, species diversity, or functional diversity of wild bee communities. Crops not providing forage for bees, predominantly soybean, corn, and wheat, were associated with decreased functional diversity, decreased above-ground nesting bees and bees with shorter active season durations, and decreased honey bee survival. Pollinator conservation efforts retaining and enhancing grasslands, wooded areas, wetlands, and crops providing bee forage will likely support the growth, reproduction, and survival of diverse wild bee communities and the success of managed honey bees in areas dominated by intensive agriculture.