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Natalie K Boyle - One of the best experts on this subject based on the ideXlab platform.
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wildflower plantings promote blue Orchard bee osmia lignaria hymenoptera megachilidae reproduction in california almond Orchards
2020Co-Authors: Natalie K Boyle, Ola Lundin, Kimiora L Ward, Devon Picklum, Gordon I Wardell, Neal M. Williams, Derek R Artz, Theresa L PittssingerAbstract:Concerns over the availability of honeybees (Apis mellifera L.) to meet pollination demands have elicited interest in alternative pollinators to mitigate pressures on the commercial beekeeping industry. The blue Orchard bee, Osmia lignaria (Say), is a commercially available native bee that can be employed as a copollinator with, or alternative pollinator to, honeybees in Orchards. To date, their successful implementation in agriculture has been limited by poor recovery of bee progeny for use during the next spring. This lack of reproductive success may be tied to an inadequate diversity and abundance of alternative floral resources during the foraging period. Managed, supplementary wildflower plantings may promote O. lignaria reproduction in California almond Orchards. Three wildflower plantings were installed and maintained along Orchard edges to supplement bee forage. Plantings were seeded with native wildflower species that overlapped with and extended beyond almond bloom. We measured bee visitation to planted wildflowers, bee reproduction, and progeny outcomes across Orchard blocks at variable distances from wildflower plantings during 2015 and 2016. Pollen provision composition was also determined to confirm O. lignaria wildflower pollen use. Osmia lignaria were frequently observed visiting wildflower plantings during, and after, almond bloom. Most O. lignaria nesting occurred at Orchard edges. The greatest recovery of progeny occurred along the Orchard edges having the closest proximity (80 m) to managed wildflower plantings versus edges farther away. After almond bloom, O. lignaria nesting closest to the wildflower plantings collected 72% of their pollen from Phacelia spp., which supplied 96% of the managed floral area. Phacelia spp. pollen collection declined with distance from the plantings, but still reached 17% 800 m into the Orchard. This study highlights the importance of landscape context and proximity to supplementary floral resources in promoting the propagation of solitary bees as alternative managed pollinators in commercial agriculture.
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examination of a managed pollinator strategy for almond production using apis mellifera hymenoptera apidae and osmia lignaria hymenoptera megachilidae
2018Co-Authors: Theresa L Pittssinger, Natalie K Boyle, Derek R Artz, Stephen S Peterson, Gordon I WardellAbstract:Pollination services provided by managed bees are essential for California almond (Prunus dulcis Mill.; Rosales: Rosaceae) production. Currently, pollination needs are met by rented or owned Apis mellifera L. (Hymenoptera: Apidae; honey bee) colonies. Excessive demand on a challenged A. mellifera industry to provide strong colonies in early spring has caused sharp increases in rental prices over the past decade, inviting the consideration of alternative pollinators in addition to, or in place of, A. mellifera. Osmia lignaria Say (Hymenoptera: Megachilidae; the blue Orchard bee) is an excellent pollinator of fruit and nut trees, but its pollination impacts when used in tandem with A. mellifera have yet to be evaluated in commercial almond Orchards. A 2-yr study was conducted in California Orchards to compare almond pollination and production using A. mellifera as sole pollinator to an alternative practice of adding O. lignaria as a co-pollinator with A. mellifera. Almond Orchard managerial decisions, such as for pesticide use and irrigation intensity, vary between almond growing regions because of local climates. Therefore, both north-central and southern sites of California's San Joaquin Valley are represented. We compared bee visitation, nut set, and nut yield between Orchards and between tree rows within Orchards. Also, O. lignaria reproductive success was recorded to assure that these bees remained in the Orchards as pollinators and to assess the ability to sustain these bees under regional Orchard conditions. We demonstrated that augmenting large commercial almond Orchards with O. lignaria can significantly increase nut set and sometimes nut yield in both regions evaluated.
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wildflower plantings do not compete with neighboring almond Orchards for pollinator visits
2017Co-Authors: Natalie K Boyle, Ola Lundin, Kimiora L Ward, Theresa L Pittssinger, Derek R Artz, Neal M. WilliamsAbstract:The engineering of flowering agricultural field borders has emerged as a research and policy priority to mitigate threats to pollinators. Studies have, however, rarely addressed the potential that flowering field borders might compete with neighboring crops for pollinator visits if they both are in bloom at the same time, despite this being a concern expressed by growers. We evaluated how wildflower plantings added to Orchard borders in a large (512 ha) commercial almond Orchard affected honey bee and wild bee visitation to Orchard borders and the crop. The study was conducted over two consecutive seasons using three large (0.48 ha) wildflower plantings paired with control Orchard borders in a highly simplified agricultural landscape in California. Honey bee (Apis mellifera L.) and wild bee visitation to wildflower plots were at least an order of magnitude higher than to control plots, but increased honey bee visitation to wildflower plots did not lead to any detectable shifts in honey bee visitation to almond flowers in the neighboring Orchard. Wild bees were rarely observed visiting almond flowers irrespective of border treatment, indicating a limited short-term potential for augmenting crop pollination using wild bees in highly simplified agricultural landscapes. Although further studies are warranted on bee visitation and crop yield from spatially independent Orchards, this study indicates that growers can support bees with alternative forage in almond Orchards without risking competition between the wildflower plantings and the crop.
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the effect of nest box distribution on sustainable propagation of osmia lignaria hymenoptera megachilidae in commercial tart cherry Orchards
2017Co-Authors: Natalie K Boyle, Theresa L PittssingerAbstract:The blue Orchard bee, Osmia lignaria (Say), is a solitary bee that is an excellent pollinator of tree fruit Orchards. Due to the annual rising costs of honey bee hive rentals, many Orchardists are eager to develop management tools and practices to support O. lignaria as an alternative pollinator. Establishing O. lignaria pollination as a sustainable industry requires careful consideration of both bee and Orchard management. Here, we test the effect of artificial nest box distribution on in-Orchard propagation of O. lignaria in Utah commercial tart cherry Orchards. Two nest box distributions were compared across three paired, 1.2-ha plots. One distribution, traditionally employed by O. lignaria consultants, included a centrally located tote for mass-nesting with smaller, surrounding 'satellite' nest boxes at Orchard margins. The other distribution was composed of smaller, more equally distributed nest boxes throughout the 1.2-ha plots. Significantly higher propagation of O. lignaria was observed in the latter nest box distribution, although all treatments resulted in bee return exceeding the number of bees initially released. These findings provide support for the use of O. lignaria in tart cherry Orchards, and demonstrate how simple changes to bee set-up and management can influence propagation efforts.
Theresa L Pittssinger - One of the best experts on this subject based on the ideXlab platform.
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wildflower plantings promote blue Orchard bee osmia lignaria hymenoptera megachilidae reproduction in california almond Orchards
2020Co-Authors: Natalie K Boyle, Ola Lundin, Kimiora L Ward, Devon Picklum, Gordon I Wardell, Neal M. Williams, Derek R Artz, Theresa L PittssingerAbstract:Concerns over the availability of honeybees (Apis mellifera L.) to meet pollination demands have elicited interest in alternative pollinators to mitigate pressures on the commercial beekeeping industry. The blue Orchard bee, Osmia lignaria (Say), is a commercially available native bee that can be employed as a copollinator with, or alternative pollinator to, honeybees in Orchards. To date, their successful implementation in agriculture has been limited by poor recovery of bee progeny for use during the next spring. This lack of reproductive success may be tied to an inadequate diversity and abundance of alternative floral resources during the foraging period. Managed, supplementary wildflower plantings may promote O. lignaria reproduction in California almond Orchards. Three wildflower plantings were installed and maintained along Orchard edges to supplement bee forage. Plantings were seeded with native wildflower species that overlapped with and extended beyond almond bloom. We measured bee visitation to planted wildflowers, bee reproduction, and progeny outcomes across Orchard blocks at variable distances from wildflower plantings during 2015 and 2016. Pollen provision composition was also determined to confirm O. lignaria wildflower pollen use. Osmia lignaria were frequently observed visiting wildflower plantings during, and after, almond bloom. Most O. lignaria nesting occurred at Orchard edges. The greatest recovery of progeny occurred along the Orchard edges having the closest proximity (80 m) to managed wildflower plantings versus edges farther away. After almond bloom, O. lignaria nesting closest to the wildflower plantings collected 72% of their pollen from Phacelia spp., which supplied 96% of the managed floral area. Phacelia spp. pollen collection declined with distance from the plantings, but still reached 17% 800 m into the Orchard. This study highlights the importance of landscape context and proximity to supplementary floral resources in promoting the propagation of solitary bees as alternative managed pollinators in commercial agriculture.
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examination of a managed pollinator strategy for almond production using apis mellifera hymenoptera apidae and osmia lignaria hymenoptera megachilidae
2018Co-Authors: Theresa L Pittssinger, Natalie K Boyle, Derek R Artz, Stephen S Peterson, Gordon I WardellAbstract:Pollination services provided by managed bees are essential for California almond (Prunus dulcis Mill.; Rosales: Rosaceae) production. Currently, pollination needs are met by rented or owned Apis mellifera L. (Hymenoptera: Apidae; honey bee) colonies. Excessive demand on a challenged A. mellifera industry to provide strong colonies in early spring has caused sharp increases in rental prices over the past decade, inviting the consideration of alternative pollinators in addition to, or in place of, A. mellifera. Osmia lignaria Say (Hymenoptera: Megachilidae; the blue Orchard bee) is an excellent pollinator of fruit and nut trees, but its pollination impacts when used in tandem with A. mellifera have yet to be evaluated in commercial almond Orchards. A 2-yr study was conducted in California Orchards to compare almond pollination and production using A. mellifera as sole pollinator to an alternative practice of adding O. lignaria as a co-pollinator with A. mellifera. Almond Orchard managerial decisions, such as for pesticide use and irrigation intensity, vary between almond growing regions because of local climates. Therefore, both north-central and southern sites of California's San Joaquin Valley are represented. We compared bee visitation, nut set, and nut yield between Orchards and between tree rows within Orchards. Also, O. lignaria reproductive success was recorded to assure that these bees remained in the Orchards as pollinators and to assess the ability to sustain these bees under regional Orchard conditions. We demonstrated that augmenting large commercial almond Orchards with O. lignaria can significantly increase nut set and sometimes nut yield in both regions evaluated.
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wildflower plantings do not compete with neighboring almond Orchards for pollinator visits
2017Co-Authors: Natalie K Boyle, Ola Lundin, Kimiora L Ward, Theresa L Pittssinger, Derek R Artz, Neal M. WilliamsAbstract:The engineering of flowering agricultural field borders has emerged as a research and policy priority to mitigate threats to pollinators. Studies have, however, rarely addressed the potential that flowering field borders might compete with neighboring crops for pollinator visits if they both are in bloom at the same time, despite this being a concern expressed by growers. We evaluated how wildflower plantings added to Orchard borders in a large (512 ha) commercial almond Orchard affected honey bee and wild bee visitation to Orchard borders and the crop. The study was conducted over two consecutive seasons using three large (0.48 ha) wildflower plantings paired with control Orchard borders in a highly simplified agricultural landscape in California. Honey bee (Apis mellifera L.) and wild bee visitation to wildflower plots were at least an order of magnitude higher than to control plots, but increased honey bee visitation to wildflower plots did not lead to any detectable shifts in honey bee visitation to almond flowers in the neighboring Orchard. Wild bees were rarely observed visiting almond flowers irrespective of border treatment, indicating a limited short-term potential for augmenting crop pollination using wild bees in highly simplified agricultural landscapes. Although further studies are warranted on bee visitation and crop yield from spatially independent Orchards, this study indicates that growers can support bees with alternative forage in almond Orchards without risking competition between the wildflower plantings and the crop.
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the effect of nest box distribution on sustainable propagation of osmia lignaria hymenoptera megachilidae in commercial tart cherry Orchards
2017Co-Authors: Natalie K Boyle, Theresa L PittssingerAbstract:The blue Orchard bee, Osmia lignaria (Say), is a solitary bee that is an excellent pollinator of tree fruit Orchards. Due to the annual rising costs of honey bee hive rentals, many Orchardists are eager to develop management tools and practices to support O. lignaria as an alternative pollinator. Establishing O. lignaria pollination as a sustainable industry requires careful consideration of both bee and Orchard management. Here, we test the effect of artificial nest box distribution on in-Orchard propagation of O. lignaria in Utah commercial tart cherry Orchards. Two nest box distributions were compared across three paired, 1.2-ha plots. One distribution, traditionally employed by O. lignaria consultants, included a centrally located tote for mass-nesting with smaller, surrounding 'satellite' nest boxes at Orchard margins. The other distribution was composed of smaller, more equally distributed nest boxes throughout the 1.2-ha plots. Significantly higher propagation of O. lignaria was observed in the latter nest box distribution, although all treatments resulted in bee return exceeding the number of bees initially released. These findings provide support for the use of O. lignaria in tart cherry Orchards, and demonstrate how simple changes to bee set-up and management can influence propagation efforts.
Sylvaine Simon - One of the best experts on this subject based on the ideXlab platform.
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Environmental impact of intensive versus semi-extensive apple Orchards: use of a specific methodological framework for life cycle assessments (LCA) in perennial crops
2016Co-Authors: Aude Alaphilippe, Sylvaine Simon, Joachim Boissy, Caroline GodardAbstract:While the management of apple Orchards is intensifying through high tree density, heavy input use and short lifespan, growers in some traditional production areas keep on planting semi-extensive Orchards. We assessed the environmental impacts of those two contrasted production systems using the last methodological recommendations for Life Cycle Assessments (LCA) in perennial crops. The use of such framework permitted to assess the weight of the unproductive stages in the Orchard lifespan impacts, and the contribution of fertiliser direct field emissions to the total impacts. Mainly due to fertilisation, the intensive Orchard displayed the higher environmental impacts over the Orchard lifespan for all calculated impact categories except energy demand. Fertilisation, including fertiliser production and application, represented half or more of the calculated impact categories in the intensive Orchard, attesting to the importance of taking these field emissions into account and to include the N-tree requirements in the calculation. Methodological considerations are discussed and the necessity to explicit the approach used to account for the duration of perennial cropping systems is also outlined. Unproductive stages weighted from 9 to 21% of the studied impact categories in the semiextensive Orchard and from 13 to 28% in the intensive Orchard, with little contribution of the nursery stage (from 0.2 to 2.6%). This study outlines that Orchard strategies (management and design) perform differently according to the context that constrains tree water need and pest and disease control.
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Management strategies in apple Orchards influence earwig community
2015Co-Authors: Laure Malagnoux, Sylvaine Simon, Gaëlle Marliac, Magali Rault, Yvan CapowiezAbstract:Our aim was to assess whether different apple Orchard management strategies (low-input, organic, Integrated Pest Management (IPM)) would have an effect on earwigs, which are important natural enemies of apple pests. These commercial Orchards were as well compared to abandoned Orchards. The density of Forficula auricularia and Forficula pubescens was studied for three years in 74 Orchards around Avignon. The pesticide usage, some Orchard characteristics and two small-scale landscape parameters were characterized. Pesticide use was significantly different between low-input, organic and IPM Orchards with particularly significant differences in the number of insecticide applications (2.2, 4.9 and 9.2 respectively). Pesticide use had a much stronger impact on earwig community than other characteristics. F. auricularia density was significantly lower in IPM Orchards (0.47 individuals per tree) compared to organic, low-input and abandoned Orchards (3.1, 4.5 and 1.6 individuals per tree, respectively). F. pubescens was almost absent from IPM Orchards and its abundance was higher in abandoned or low-input Orchards compared to organic Orchards (1.5 and 2.8 vs 0.8 individuals per tree). The percentage of F. pubescens in the earwig community decreased from abandoned (52%) to low-input (40%), organic (15%) and IPM Orchards (0.5%). These results were confirmed by LD50 assays showing that for the two pesticides causing mortality close to normal application rates (chlorpyrifos-ethyl and acetamiprid), F. pubescens was significantly more sensitive than F. auricularia. Since earwigs are also easy to capture and identify, they may be useful to estimate the effects of management strategies and their modification in pome fruit Orchards.
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genetic inferences about the population dynamics of codling moth females at a local scale
2011Co-Authors: Pierre Franck, Benoit Ricci, Sylvaine Simon, Jérôme Olivares, Jean-marie Cornuet, Etienne K Klein, Claire LavigneAbstract:Estimation of demographic parameters is important for understanding the functioning of natural populations and the underlying ecological and evolutionary processes that may impact their dynamics. Here, we used sibship assignment methods to shed light on the local dynamics of codling moth females in eight Orchards in a 90-ha domain near Valence, France. Based on full-sib inference among 1,063 genotyped moths, we estimated (1) the effective number of females that had offspring, (2) their fertility and (3) the distribution of their oviposition sites within and among Orchards. The average number of females in all the Orchards increased between the first (~130) and the second (~235) annual generations. The average fertilities of the females were similar at each generation according to the host plant considered (apple, pear, or walnut), but differed between commercial (~10) and non-treated (~25) apple Orchards. Females mainly clustered their eggs on contiguous trees along Orchard borders, but they also occasionally dispersed their eggs among different Orchards independently of the cultivated host plants or the inter-Orchard distances (up to 698 m) during the second annual generation. The mean distance between two oviposition sites was 30 m. Sibship estimates of both the effective number of females and the inter-Orchard migration rates (~5%) were in agreement with the observed genetic differentiation among the eight Orchards (0.006 < F st < 0.013). These results confirm and extend previous field and laboratory observations in Cydia pomonella, and they demonstrate that sibship assignments based on genetic data are an interesting alternative to mark-release-recapture methods for inferring insect population dynamics.
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Biodiversity and pest management in Orchard systems. A review
2010Co-Authors: Sylvaine Simon, Jeancharles Bouvier, Jean Francois Debras, Benoît SauphanorAbstract:Conventional agriculture is based on a high level of chemical inputs such as pesticides and fertilisers, leading to serious environmental impacts, health risks and loss of biodiversity in agrosystems. The reduction of pesticide use is a priority for intensively sprayed agricultural systems such as Orchards. The preservation and promotion of biodiversity within Orchards and their boundaries is therefore an issue to explore. Indeed, Orchard systems contain high plant diversity and perennial multi-strata designs that provide wealthy resources and habitats to living communities such as beneficial organisms. Orchards thus offer favourable areas to maintain food-webs within the agrosystem, provided that favourable situations are not altered by cultural practices such as applying an excess of pesticides. Here, we analysed literature on the effects of the manipulation of plant diversity and habitats on the control of pests by arthropod and bird communities in apple, pear and peach Orchards. Many investigations focus on the role of plant management to enhance biodiversity in Orchards but only 22 research reports presenting 30 case studies were dedicated to the study of the ecosystem service provided by plant diversity for Orchard pest control. The underlying mechanisms were seldom demonstrated, and the tested grass covers and tree assemblages aimed at favouring either the beneficial complex or only some beneficial species to control one or a few pests. The effect of plant management on pest control was mostly positive (16 cases) or null (9), but also negative in some cases (5). This finding reveals the difficulties of identifying selected plants or plant assemblages for the control of key pests. We conclude that further research is needed to identify the processes involved on different scales for biological control. Orchard systems should be re-designed to optimise ecosystem services provided by biodiversity.
Yousry A Elkassaby - One of the best experts on this subject based on the ideXlab platform.
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genetic diversity of norway spruce picea abies l karst seed Orchard crops effects of number of parents seed year and pollen contamination
2018Co-Authors: Jorn Henrik Sonstebo, Mari Mette Tollefsrud, Tor Myking, Arne Steffenrem, A E Nilsen, O M Edvardsen, O R Johnskas, Yousry A ElkassabyAbstract:Abstract Seed from Orchards, established from breeding programs, often dominate the planting stock in economically important tree species, such as Norway spruce. The genetic diversity in seed Orchards’ crops depends on effective population size which in turn is affected by many factors such as: number of parents in the Orchard, seed Orchards’ design, fecundity, and pollen contamination. Even though seed Orchards’ seed is extensively used over large regions, very few studies have addressed how well their crops reflect the genetic diversity present in the regions where they are planted. Here we have investigated the genetic diversity (by means of 11 microsatellites) of two Norway spruce seed Orchard populations with different number of parents (60 and 25) and compared this with seed crops collected in the semi natural forest and natural unmanaged populations. We found that the ratio between the effective population size (Ne) and actual number of parents (N) varied between 0.60 and 0.76 in the Orchards’ seedlots. A reduction in genetic diversity (mainly allelic richness) was detected in a few seedlots, mainly where the number of parents was low. Our results also show that pollen contamination play an important role in maintaining the genetic diversity in Orchards’ seedlots, particularly when the number of parents is low. The population genetic structure among seed orhcards and natural populations is shallow suggesting that regeneration with seed from current seed Orchards will have limited effect on the overall genetic diversity.
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clonal row vs random seed Orchard designs mating pattern and seed yield of western hemlock tsuga heterophylla raf sarg
2003Co-Authors: Yousry A ElkassabyAbstract:Comparisons of the mating pattern (selfing rate and level of correlated matings) and seed yield between clonalrow and the traditional random design in a western hemlock (Tsuga heterophylla (Raf.) Sarg.) seed Orchard were conducted. The study included: (1) a reproductive phenology survey to determine the duration of pollination season, (2) controlled selfing trial to determine clonal propensity to selfing, (3) seed yield comparison between seed Orchards designs and among clones within seed Orchards, and (4) determination of selfing and correlated matings rates using allozyme markers. Results indicated that the Orchard has an extended, 22-day, pollination period and clones were characterized based on their reproductive activity as early, medium, and late. The majority of the 25 self-pollinated clones yielded very low seed set, however, few clones showed higher selfing propensity with percent of filled seed ranging from 8 to 29 %. Seed Orchard design had no significant effect on seed yield @ = 0.27). Outcrossing rate estimates were significantly different between the clonal-row (t = 0.899) and random (t = 0.970) seed Orchards, and both estimates significantly departed from complete outcrossing (i.e., t = 1.0), indicating that selfing is higher in the clonal-row design. Estimates of correlated mating substantially varied between the two seed Orchard designs with 35 and 8 % for the clonal-row and random seed Orchards, respectively, demonstrating genetic quality differences of seed produced from the two seed Orchard designs. It was concluded that if clonal-row design is considered for advanced generation seed Orchards, then a slight modification involving staggering the clonal-rows will allow each clone to be flanked by four other clones. Together with the use of effective pollen management such as carefully timed, clone-specific, multiple supplemental-mass-pollination applications may reduce selfing and correlated matings.
Ola Lundin - One of the best experts on this subject based on the ideXlab platform.
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wildflower plantings promote blue Orchard bee osmia lignaria hymenoptera megachilidae reproduction in california almond Orchards
2020Co-Authors: Natalie K Boyle, Ola Lundin, Kimiora L Ward, Devon Picklum, Gordon I Wardell, Neal M. Williams, Derek R Artz, Theresa L PittssingerAbstract:Concerns over the availability of honeybees (Apis mellifera L.) to meet pollination demands have elicited interest in alternative pollinators to mitigate pressures on the commercial beekeeping industry. The blue Orchard bee, Osmia lignaria (Say), is a commercially available native bee that can be employed as a copollinator with, or alternative pollinator to, honeybees in Orchards. To date, their successful implementation in agriculture has been limited by poor recovery of bee progeny for use during the next spring. This lack of reproductive success may be tied to an inadequate diversity and abundance of alternative floral resources during the foraging period. Managed, supplementary wildflower plantings may promote O. lignaria reproduction in California almond Orchards. Three wildflower plantings were installed and maintained along Orchard edges to supplement bee forage. Plantings were seeded with native wildflower species that overlapped with and extended beyond almond bloom. We measured bee visitation to planted wildflowers, bee reproduction, and progeny outcomes across Orchard blocks at variable distances from wildflower plantings during 2015 and 2016. Pollen provision composition was also determined to confirm O. lignaria wildflower pollen use. Osmia lignaria were frequently observed visiting wildflower plantings during, and after, almond bloom. Most O. lignaria nesting occurred at Orchard edges. The greatest recovery of progeny occurred along the Orchard edges having the closest proximity (80 m) to managed wildflower plantings versus edges farther away. After almond bloom, O. lignaria nesting closest to the wildflower plantings collected 72% of their pollen from Phacelia spp., which supplied 96% of the managed floral area. Phacelia spp. pollen collection declined with distance from the plantings, but still reached 17% 800 m into the Orchard. This study highlights the importance of landscape context and proximity to supplementary floral resources in promoting the propagation of solitary bees as alternative managed pollinators in commercial agriculture.
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wildflower plantings do not compete with neighboring almond Orchards for pollinator visits
2017Co-Authors: Natalie K Boyle, Ola Lundin, Kimiora L Ward, Theresa L Pittssinger, Derek R Artz, Neal M. WilliamsAbstract:The engineering of flowering agricultural field borders has emerged as a research and policy priority to mitigate threats to pollinators. Studies have, however, rarely addressed the potential that flowering field borders might compete with neighboring crops for pollinator visits if they both are in bloom at the same time, despite this being a concern expressed by growers. We evaluated how wildflower plantings added to Orchard borders in a large (512 ha) commercial almond Orchard affected honey bee and wild bee visitation to Orchard borders and the crop. The study was conducted over two consecutive seasons using three large (0.48 ha) wildflower plantings paired with control Orchard borders in a highly simplified agricultural landscape in California. Honey bee (Apis mellifera L.) and wild bee visitation to wildflower plots were at least an order of magnitude higher than to control plots, but increased honey bee visitation to wildflower plots did not lead to any detectable shifts in honey bee visitation to almond flowers in the neighboring Orchard. Wild bees were rarely observed visiting almond flowers irrespective of border treatment, indicating a limited short-term potential for augmenting crop pollination using wild bees in highly simplified agricultural landscapes. Although further studies are warranted on bee visitation and crop yield from spatially independent Orchards, this study indicates that growers can support bees with alternative forage in almond Orchards without risking competition between the wildflower plantings and the crop.
