Pollinator Community Composition Research Articles

Floral and pollinator functional diversity mediate network structure along an elevational gradient

AbstractElevational gradients in alpine ecosystems are well suited to study how plant and pollinator communities respond to climate change. In the Austrian Alps, we tested how the taxonomic and functional diversity of plants and their pollinators change with increasing elevation and how this affects plant–pollinator network structure. We measured the phenotypes of flowering plants and their pollinators and observed their interactions in 24 communities along an elevational gradient. To assess variation in floral and pollinator traits, we then quantified trait spaces (n-dimensional hypervolumes) occupied by flowers and pollinators in each community. To assess plant–pollinator network structure, we quantified the levels of complementary specialization (H2’), modularity and nestedness (weighted NODF) for each community. As elevation increased, most measures of diversity and network specialization either declined linearly or in an oscillating manner. Communities that exhibited higher pollinator functional diversity exhibited larger degrees of complementary specialization and modularity; and communities with greater floral and pollinator functional diversity and higher phylogenetic diversity were less nested. Altogether, the degree to which elevation, species diversity, functional diversity and network structure changed in conjunction suggests environmental effects on the functional and phylogenetic diversity of plants and pollinators and consequently network structure. Our results suggest that the effects of climate change on plant and pollinator community composition will impact plant–pollinator network structure and potentially pollination services at the community scale.

Differential response of plant and insect pollinator communities to fragmentation in coastal dune slacks

Abstract Habitat destruction and fragmentation are one of the main drivers of pollinator decline and biodiversity loss in general. However, the exact effects of habitat fragmentation on pollinator communities are still poorly understood, and it remains unclear which patch characteristics are most important in driving pollinator diversity and community composition. In this study, we inventoried plant and insect diversity in a total of 19 fragmented dune slacks in Belgium. Specifically, we assessed the effects of dune slack area and connectivity on plant and pollinator diversity and community composition. Additionally, we investigated to what extent plant diversity had an impact on insect pollinator communities. The results indicated that species richness of both plants and insects was significantly related to patch area, whereas patch connectivity only had a significant effect on plant diversity. Nestedness analyses showed that plant communities of small dune slacks were a subset of the communities of large patches, but no such patterns were found for insect communities. Turnover in pollinator communities was high and significantly related to the distance separating dune slacks. Overall, our results highlight the importance of large patches for sustaining both plant and pollinator communities. Additionally, enhancing connectivity has the potential to promote plant diversity and consequently benefit pollinator species.

Conserved grasslands support similar pollinator diversity as pollinator-specific practice regardless of proximal cropland and pesticide exposure.

Pollinator diversity and abundance are declining globally. Cropland agriculture and the corresponding use of agricultural pesticides may contribute to these declines, while increased pollinator habitat (flowering plants) can help mitigate them. Here we tested whether the relative effect of wildflower plantings on pollinator diversity and counts were modified by proportion of nearby agricultural land cover and pesticide exposure in 24 conserved grasslands in Iowa, USA. Compared with general grassland conservation practices, wildflower plantings led to only a 5% increase in pollinator diversity and no change in counts regardless of the proportion of cropland agriculture within a 1 km radius. Pollinator diversity increased earlier in the growing season and with per cent flower cover. Unexpectedly, neither insecticide nor total pesticide concentrations on above-ground passive samplers were related to pollinator diversity. However, pollinator community composition was most strongly related to date of sampling, total pesticide concentration, and forb or flower cover. Our results indicate very little difference in pollinator diversity between grassland conservation practices with and without wildflower plantings. Given the relatively high economic costs of wildflower plantings, our research provides initial evidence that investment in general grassland conservation may efficiently conserve pollinator diversity in temperate regions of intensive cropland agriculture.

Wild pollinator communities benefit from mixed cultivation of oilseed rape and milk vetch

AbstractGlobally, insect pollinators that are linked to increased yields in many crops have experienced severe population declines. Crop diversification is often proposed as an effective conservation measure to boost pollinator populations. Here, we investigate the potential benefits of mixed oilseed rape/milk vetch cultivation for wild pollinator communities by comparing it with oilseed rape monocultures. Studying 8 mixed and 10 monocropping fields positioned along a gradient of increasing semi‐natural habitat coverage in mountainous agricultural landscapes, we found that agricultural landscapes with mixed cultivation harboured higher wild pollinator diversity than oilseed rape monocropping landscapes. This positive effect was observed irrespective of the proportion of semi‐natural habitat. Meanwhile, the pollinator community composition in mixed cultivation landscapes was similar to that of oilseed rape monoculture landscapes, and, contrary to expectations, mixed cultivation did not benefit specific pollinator trait groups like cavity‐nesting bees. Overall, we believe the higher pollinator diversity linked to mixed cultivation can increase insect‐pollinated crop yields, and mixed oilseed rape‐milk vetch cultivation might represent a potential mitigation measure for the negative impacts agricultural intensification has on wild pollinator communities.

Sustained mangrove reproduction despite major turnover in pollinator community composition at expanding range edge.

How well plants reproduce near their geographic range edge can determine whether distributions will shift in response to changing climate. Reproduction at the range edge can be limiting if pollinator scarcity leads to pollen limitation, or if abiotic stressors affect allocation to reproduction. For many animal-pollinated plants with expanding ranges, the mechanisms by which they have overcome these barriers are poorly understood. In this study, we examined plant-pollinator interactions hypothesized to impact reproduction of the black mangrove, Avicennia germinans, which is expanding northward in coastal Florida, USA. We monitored insects visiting A. germinans populations varying in proximity to the geographic range edge, measured the pollen loads of the most common insect taxa and pollen receipt by A. germinans stigmas, and quantified flower and propagule production. We found that despite an 84 % decline in median floral visits by insects at northernmost versus southernmost sites, range-edge pollen receipt remained high. Notably, local floral visitor assemblages exhibited substantial turnover along the study's latitudinal gradient, with large-bodied bees and hover flies increasingly common at northern sites. We also observed elevated flower production in northern populations and higher per capita reproductive output at the range edge. Furthermore, mean propagule mass in northern populations was 18 % larger than that from the southernmost populations. These findings reveal no erosion of fecundity in A. germinans populations at range limits, allowing rapid expansion of mangrove cover in the region. These results also illustrate that substantial turnover in the assemblage of flower-visiting insects can occur at an expanding range edge without altering pollen receipt.

B.Y.O. Bees: Managing wild bee biodiversity in urban greenspaces.

As cities become more populated and the density of urban development increases, local biodiversity is threatened. Urban greenspaces have the capacity to preserve pollinator biodiversity, but the quality of support they provide depends on greenspace landscape attributes, including the availability of pollinator habitat and foraging resources. Wild native bees provide important pollination services to urban ecosystems, yet relatively little is known about how urban landscape management influences pollinator community composition and diversity. Our study explores how wild bee communities are affected by greenspace and landscape-level features like pollinator management practices, in urban greenspaces in and around Appleton Wisconsin: a mid-sized urban community spanning more than 100 sq. km. We sampled and identified native bees periodically between late-May 2017 and mid-September of 2018 using standardized arrays of pan traps at 15 sites around the city. We classified greenspaces based on their level of development (urban or suburban) and whether they were managed or unmanaged for increasing wild pollinator diversity. We quantified floral species diversity, floral color diversity, tree species diversity, and proximity of sites to open water for each site and used remotely sensed satellite data from both the USGS National Land Cover Database (NLCD) and the Normalized Difference Vegetation Index (NDVI). All variables were tested as potential correlates of wild bee abundance and species richness. Active pollinator management sites supported higher levels of bee abundance and richness. Notably, active greenspace management (e.g. planting native wildflowers) was a stronger correlate of bee abundance and richness than greenspace size and other landscape-level attributes. Within-greenspace attributes such as floral diversity, tree diversity, and proximity to open water contributed positively to both bee abundance and richness. Based on these findings, we suggest that urban greenspaces may be managed more efficiently and cost-effectively by focusing resources on active management by planting wildflowers, removing invasive species, creating nesting habitat, and providing water resources, rather than simply expanding in area.

Moth community among apples during bloom in Northwest Arkansas: likely pollinators and activity periods.

Apples are a fruit crop of economic and nutritional importance that require cross-pollination primarily by insects for sustainable production. It was recently demonstrated that nocturnal pollinators can contribute as much to apple pollination as diurnal pollinators. However, information concerning nocturnal pollinator identity, activity periods, and community composition in apples is lacking, which limits research expansion. To address this knowledge gap, nocturnal moths in an apple orchard were surveyed during apple bloom from 2018 to 2020 using blacklight traps, with samples collected hourly to delineate moth activity. Observations during the same periods were made to identify moths visiting apple flowers, whose capture data were then compared to other captured moth species to provide useful information concerning community composition during apple bloom. Blacklight surveys yielded 1,087 moths representing at least 68 species from 12 families, wherein 15 species from five families were observed visiting apple flowers. Captured moths were most abundant and diverse in the first two hours after sunset. Most captured moth species did not visit flowers and are likely not associated with apple pollination. However, moth species that were observed visiting flowers were the most abundant overall and most diverse by hour in surveys. Data indicate a rich moth community present among apple orchards during bloom and identify likely moth pollinators of apples. Though more research is required to establish the precise relationships between moth pollination and apples, the information provided here allows for targeted efforts to do so.

Proximity to oilseed rape fields affects plant pollination and pollinator-mediated selection on a co-flowering plant on the Tibetan Plateau.

The ecological effects of mass-flowering crops on pollinator abundance and species richness of neighbouring habitats are well established, yet the potential evolutionary consequences remain unclear. We studied effects of proximity to a mass-flowering crop on the pollination of local co-flowering plants and on patterns of natural selection on a pollination-generalised plant on the Tibetan Plateau. We recorded pollinator visitation rates and community composition at different distances (near vs. far) to oilseed rape (Brassica napus) fields in two habitat types and quantified pollinator-mediated selection on attractive traits of Trollius ranunculoides. The proximity to oilseed rape increased pollinator visitation in neighbouring alpine meadows and changed pollinator composition in neighbouring shrub meadows. Trollius ranunculoides in the alpine meadow near oilseed rape received three times more pollinator visits (mainly bees) and consequently had a 16.5% increase in seed set but also received slightly more heterospecific pollen per stigma. In contrast, pollinator visitation to T. ranunculoides in the shrub meadow near oilseed rape was three times lower (mainly flies), leading to a 10.7% lower seed despite no effect on pollen deposition. The proximity to the oilseed rape field intensified pollinator-mediated selection on flower size and weakened selection on flower height of T. ranunculoides in the alpine meadow but did not affect phenotypic selection on either trait in the shrub meadow. Our study highlights context-dependent variation in plant-pollinator interactions close to mass-flowering oilseed rape, suggesting potential effects on the evolution of flower traits of native plants through altered pollinator-mediated selection. However, context dependence may make these effects difficult to predict.

Forest and grassland habitats support pollinator diversity more than wildflowers and sunflower monoculture

Abstract Intensively managed agricultural landscapes often lack suitable habitats to support diverse wildlife, particularly harming pollinator communities. Besides mass flowering crops, remnant patches of natural and semi‐natural vegetation may play a key role in maintaining and conserving biodiversity. Yet, the effects of different natural habitats, including forests and grasslands, on different pollinator communities are poorly understood at the landscape scale. We examined the abundance, richness, and diversity of wild bees and hoverflies, two key pollinator groups, across a land‐use gradient spanning forest edges, grassland, wildflower strips, and sunflower monoculture. We also examined the distribution of hoverfly larvae trophic guilds and wild bee nesting traits across the above‐mentioned land‐use gradient. Finally, we evaluated the impact of landscape structure (forest, grassland, and water cover in the surrounding landscape) on pollinator community composition. Our results indicate that forest and grassland habitats supported a higher abundance and greater richness of pollinators than wildflower strips and sunflower monocultures. Furthermore, hoverflies were more sensitive to habitat and floristic homogenization than wild bees. Sunflower and wildflower habitats also hosted a lower diversity of larvae trophic guilds and wild bee nesting guilds as compared to forests and grasslands. Our study suggests that conserving and restoring forest and grassland habitats within agricultural mosaics may serve as the main ‘refuge’ for wild pollinators.

Putative Signals of Generalist Plant Species Adaptation to Local Pollinator Communities and Abiotic Factors.

The reproductive success of flowering plants with generalized pollination systems is influenced by interactions with a diverse pollinator community and abiotic factors. However, knowledge about the adaptative potential of plants to complex ecological networks and the underlying genetic mechanisms is still limited. Based on a pool-sequencing approach of 21 natural populations of Brassica incana in Southern Italy, we combined a genome-environmental association analysis with a genome scan for signals of population genomic differentiation to discover genetic variants associated with the ecological variation. We identified genomic regions putatively involved in the adaptation of B. incana to the identity of local pollinator functional categories and pollinator community composition. Interestingly, we observed several shared candidate genes associated with long-tongue bees, soil texture, and temperature variation. We established a genomic map of potential generalist flowering plant local adaptation to complex biotic interactions, and the importance of considering multiple environmental factors to describe the adaptive landscape of plant populations.

Experimental insecticide applications change tomato pollinator assemblages and do not increase fruit production

One of the main threats to pollinators is insecticide application, many products widely used have lethal and sub-lethal (affects behavior, health, and fitness) effects on pollinators, and hence pollination. As sensitivity to such effects varies across species, insecticide application also changes the pollinator community composition within agricultural landscapes and hence affects the assemblages of crop pollinators. However, studies on the effects on native bees and their consequences on pollination services are lacking for many pesticides. Here, we use an experimental setup placed in four study regions (each with three blocks, with 15 experimental per block) to evaluate the effect of lambda-cyhalothrin pulverization on pollination and production of tomato (Solanum lycopersicum L.). Lambda-cyhalothrin is a pyrethroid insecticide highly toxic to the environment and commonly used in the tomato crops of Brazil, a crop that is pollinated by a diverse community of native bees. The effect of an alternative insecticide, classified as biological, on pollinators and pollination of tomatoes was also evaluated. For each experimental individual under each treatment, we collected data on the pollinator visitation before and after starting pulverization up to 23 days after the last application of pesticides. We also evaluated the effect of the three treatments on stigma pollen load, fruit, and seed production. We found that in all treatments (even control) visitation rate was higher before than after pulverization. During the spraying period, the plants sprayed with pyrethroid insecticide showed lower pollinator visitation compared to other treatments, these plants also ended with lower pollen deposition on the stigma. Paratrigona lineata was more susceptible to insecticide pulverization than other bee species. Recovery of visitation rates was detected after 23 days for all treatments. Despite the effect on visitation and pollen deposition, fruit and seed sets were similar among treatments. Overall, our results show that pyrethroid insecticide pulverization causes changes in the behavior of native flower-visiting bees. The mechanisms that explain these changes deserve further investigation, and further studies are needed to understand the large-scale effects of the use of pyrethroid insecticide on insect biodiversity and agricultural landscapes. As the biological insecticide had lower negative effects on bees, future studies that take into account both the effects on pest damage and pollination are needed to define more sustainable management approaches, minimizing negative impacts on biodiversity.

Insect pollination services in actively and spontaneously restored quarries converge differently to natural reference ecosystem.

Ecological restoration has the potential to accelerate the recovery of biodiversity and ecosystem services in degraded ecosystems. However, current research queries whether active restoration is necessary. We evaluated plant-pollinator networks during spring at replicated sites within an actively restored quarry, at abandoned quarries undergoing spontaneous restoration, and within a natural reference area, to compare pollinator community composition and function. Overall, we aimed to assess which approach is more effective in rehabilitating pollination networks. We found that while both approaches allowed for the restoration of pollination function, active restoration provided faster recovery: pollination network structure was more similar to the reference ecosystem after 20-30 years of active restoration, than 40 years of natural succession in spontaneously restored areas. Different restoration approaches sustained distinct pollinator communities providing a similar service in different areas: honey bees played an important role in the natural area, bumblebees in the abandoned quarries and wild bees in the restored sites, suggesting a possible conflict between diverse wild bee communities and honey bee homogenized pollinator communities. In quarries, flower resource availability and diversity influenced networks' structural properties by constraining species interactions and composition. In spontaneously restored areas a rich herbaceous layer of ruderal species from early successional stages buffered against the shortage of flower resources at critical periods. Active restoration, though effective, should include practices that consider wild bee communities and mitigate flower resource scarcity. The use of "bridging" plants that flower in different periods, should be considered in active restoration programs to enhance the pollinator community.

Stability of crop pollinator occurrence is influenced by bee community composition

Bees provide a vital ecosystem service to agriculture by contributing to the pollination of many leading global crops. Human wellbeing depends not only on the quantity of agricultural yields, but also on the stability and resilience of crop production. Yet a broad understanding of how the diversity and composition of pollinator communities may influence crop pollination service has previously been hindered by a scarcity of standardized data. We used outputs from Bayesian occupancy detection models to examine patterns in the inter-annual occupancy dynamics of the bee pollinator communities of four contrasting crops (apples, field bean, oilseed and strawberries) in Great Britain between 1985 and 2015. We compared how the composition and species richness of different crop pollinator communities may affect the stability of crop pollinator occurrence. Across the four crops, we found that the inter-annual occupancy dynamics of the associated pollinator communities tended to be more similar in smaller communities with closely related pollinator species. Our results indicate that crop pollinator communities composed of a small number of closely related bee species show greater variance in mean occupancy compared to crops with more diverse pollinator communities. Lower variance in the occurrence of crop pollinating bee species may lead to more stable crop pollination services. Finally, whilst our results initially indicated some redundancy within most crop pollinator communities, with no, or little, increase in the variance of overall mean occupancy when species were initially removed, this was followed by a rapid acceleration in the variance of crop pollinator occurrence as each crop's bee pollinator community was increasingly depreciated. High inter-annual variations in pollination services have negative implications for crop production and food security. High bee diversity could ensure more stable and resilient crop pollination services, yet current agri-environment schemes predominantly benefit a limited suite of common species. Management may therefore benefit from targeting a wider diversity of solitary species in order to safeguard crop pollination service in the face of increasing environmental change.

Defensive mutualists affect outcross pollen transfer and male fitness in their host plant

Ant guards can increase plant fitness by deterring herbivores, but they may also reduce it by interfering with pollination. While ant impacts on herbivory have been well‐studied, much less is known about their impacts on pollinators and associated consequences for plant pollination, particularly pollen transfer dynamics and outcrossing/selfing rates. We used field experiments to quantify the effect of ant guards on pollinator community composition, frequency and duration of flower visits, and cascading effects on outcrossing pollen transfer and pollen exports in Turnera velutina (Passifloraceae). Although ant patrolling did not affect pollinator community composition or visitation frequency, it decreased flower visit duration and the time pollinators spent foraging inside flowers. Such behavioural changes resulted in reduced pollen deposition on stigmas, decreased pollen exports (a proxy for male fitness) and significantly doubled outcross pollen transfer. This study contributes to our understanding of how non‐pollinator mutualists can shape plant reproductive processes. We discuss the downstream effects that variation in biotic defences, such as rewards for guarding ants, can have on plant pollen transfer patterns and fitness.In conclusion, guarding ants influence pollen transfer patterns in Turnera velutina, increasing outcrossing in a self‐compatible species at the cost of male fitness. We show how non‐pollinators, such as defensive ant mutualists, can shape plant reproductive traits and discuss the consequences these interactions may have for plant mating systems.

Interactive effects of climate and land use on pollinator diversity differ among taxa and scales.

Changes in climate and land use are major threats to pollinating insects, an essential functional group. Here, we unravel the largely unknown interactive effects of both threats on seven pollinator taxa using a multiscale space-for-time approach across large climate and land-use gradients in a temperate region. Pollinator community composition, regional gamma diversity, and community dissimilarity (beta diversity) of pollinator taxa were shaped by climate-land-use interactions, while local alpha diversity was solely explained by their additive effects. Pollinator diversity increased with reduced land-use intensity (forest < grassland < arable land < urban) and high flowering-plant diversity at different spatial scales, and higher temperatures homogenized pollinator communities across regions. Our study reveals declines in pollinator diversity with land-use intensity at multiple spatial scales and regional community homogenization in warmer and drier climates. Management options at several scales are highlighted to mitigate impacts of climate change on pollinators and their ecosystem services.

Landscape-scale drivers of pollinator communities may depend on land-use configuration.

Research into pollinators in managed landscapes has recently combined approaches of pollination ecology and landscape ecology, because key stressors are likely to interact across wide areas. While laboratory and field experiments are valuable for furthering understanding, studies are required to investigate the interacting drivers of pollinator health and diversity across a broader range of landscapes and a wider array of taxa. Here, we use a network of 96 study landscapes in six topographically diverse regions of Britain, to test the combined importance of honeybee density, insecticide loadings, floral resource availability and habitat diversity to pollinator communities. We also explore the interactions between these drivers and the cover and proximity of semi-natural habitat. We found that among our four drivers, only honeybee density was positively related to wild pollinator abundance and diversity, and the positive association between abundance and floral resources depended on insecticide loadings and habitat diversity. By contrast, our exploratory models including habitat composition metrics revealed a complex suite of interactive effects. These results demonstrate that improving pollinator community composition and health is unlikely to be achieved with general resource enhancements only. Rather, local land-use context should be considered in fine-tuning pollinator management and conservation. This article is part of the theme issue 'Natural processes influencing pollinator health: from chemistry to landscapes'.

Native Flowering Border Crops Attract High Pollinator Abundance and Diversity, Providing Growers the Opportunity to Enhance Pollination Services.

Over the past century, habitat loss from agricultural intensification has contributed to pollinator decline. One way to mitigate the harmful effects of agricultural intensification is through the re-introduction of native flowering plants as border strips that provide supplemental floral and nesting resources to pollinators. However, border crop species vary in bloom period and flower densities, and are thus likely to attract different suites of pollinator species. Resulting differences in pollinator community composition are likely to affect their ability to provide pollination services to adjacent crop habitat. To address these issues, we implemented a two-year study on the impact of different flowering border crops on pollinator abundance, richness, and community composition. We also examined which crop features (bloom duration, number of flowers, floral area) were most likely to affect pollinator densities. We found that native flowering plant border crops of diverse prairie mix and monocultures of silflower (Silphium integrifolium Michx.) and cup plant (Silphium perfoliatum L.) attracted the highest abundance and species richness of bees and pollinator groups combined, while alfalfa (Medicago sativa L.) attracted the highest lepidopteran abundance and species richness. We also found a significant, positive relationship between pollinator abundance and floral resource amount and bloom duration. These findings offer valuable insight into the impacts of different land management strategies on different pollinator groups, and thus provide landowners with management options for attracting specific pollinator groups and species.

Evaluating the impact of increased pollinator habitat on bee visitation and yield metrics in soybean crops

Agricultural intensification has significantly altered ecosystem functioning and aided in the reduction of global biodiversity. While agriculture requires increased reliance on animal pollination, pollinator populations have declined. To combat this, adding pollinator habitat into agricultural landscapes is increasingly common, but many questions remain about its functionality and impact on agroecosystems, particularly in pollinator-independent crops. Our study uses pollinator habitats planted on experimental research stations in the southeastern USA to evaluate their impact on pollinator communities within a nearby cropping system (soybeans) and the resulting yield. We found the species composition of pollinator communities within the habitat to be significantly different than the communities in soybeans. Even still, we identified more than 30 bee species visiting soybean flowers and verified that a subset of these species had actively collected soybean pollen. Bees from soybean fields planted adjacent to the habitat had more habitat pollen types present, while some species had more non-habitat types present when in the negative control sites. The presence of habitat had a positive effect on some yield measurements with adjacent soybean sites having 6.52% heavier seeds per plant on average. These findings demonstrate that pollinator habitat can be an important resource for supporting pollinators and highlights the importance of considering pollinator habitat in pollinator-independent crops, as they may still benefit from and be attractive to pollinator communities.

Inventorying and monitoring crop pollinating bees: Evaluating the effectiveness of common sampling methods

Abstract Wild bees provide a critical ecosystem service by pollinating globally important crops. Documented bee declines, notably in agricultural landscapes, therefore threaten future food security. Yet, evaluations of methods to inventory bees are rarely carried out in different crops or focus specifically upon crop pollinating species. We utilise standardised field datasets to elucidate differences in the capacity of transect walks, observation plots and pan traps to sample wild bee pollinator communities in four contrasting crops. Our results indicate that individual survey methods detect different components of crop pollinator communities, with guild and body size potentially important causal factors behind these differences. Transects detected half or less of the total potential pollinator community in three of our four study crops. Whilst transects were the most efficient method for sampling bumblebees, they often missed smaller solitary species, which were most efficiently sampled by yellow pan traps. Crop type is likely an important determinant of the most suitable survey methods to sample bee pollinator communities. Whilst transects alone are sufficient in crops pollinated predominantly by bumblebees, pan traps, and potentially observation plots, may be an important addition in some crops where smaller solitary bee species are potentially important pollinators. Our results indicate that the most efficient methods to sample bee species in agricultural landscapes are dependent upon crop type and pollinator community composition. We use our findings to make a set of recommendations on the inventorying and monitoring of bee pollinator crop communities that can inform regional and national monitoring programmes.

Evaluating the Impact of Increased Pollinator Habitat on Surrounding Agricultural Systems

Agricultural intensification has majorly changed ecosystem functioning and aided in the reduction of global biodiversity. While agriculture requires increased reliance on animal pollination, pollinator populations have declined. To combat this, adding pollinator habitat into agricultural landscapes is increasingly common, but many questions remain about its functionality and impact on agroecosystems, particularly in pollinator-independent crops. Our study uses pollinator habitats planted on experimental research stations to evaluate their impact on pollinator communities within a nearby cropping system (soybeans) and the resulting yield. We found the species composition of pollinator communities within the habitat to be significantly different than the communities in soybeans. Even still, we identified more than 30 bee species visiting soybean flowers and verified that a subset of these species had actively collected soybean pollen. Bees from soybean fields planted adjacent to the habitat had more habitat pollen types present, while some species had more non-habitat types present when in the negative control sites. The presence of habitat had a positive effect on some yield measurements with adjacent soybean sites having 6.52% heavier seeds per plant on average. These findings demonstrate that pollinator habitat can be an important resource for supporting pollinators and highlights the importance of considering pollinator habitat in pollinator-independent crops, as they may still benefit from and be attractive to pollinator communities.