Author
Mark Otieno
Other affiliations: Pennsylvania State University, University of Würzburg, University of Reading
Bio: Mark Otieno is an academic researcher from University of Embu. The author has contributed to research in topics: Pollinator & Pollination. The author has an hindex of 10, co-authored 19 publications receiving 2804 citations. Previous affiliations of Mark Otieno include Pennsylvania State University & University of Würzburg.
Topics: Pollinator, Pollination, Species richness, Honey bee, Ecosystem services
Papers
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National University of Río Negro1, University of Würzburg2, Rutgers University3, National University of Comahue4, Swedish University of Agricultural Sciences5, Commonwealth Scientific and Industrial Research Organisation6, University of California, Berkeley7, University of Leeds8, Naturalis9, University of Calgary10, Hebrew University of Jerusalem11, Lüneburg University12, ETH Zurich13, National University of Tucumán14, Federal University of Ceará15, Federal University of Bahia16, Plant & Food Research17, Michigan State University18, Agriculture and Agri-Food Canada19, The Nature Conservancy20, University of Göttingen21, University of Queensland22, Cornell University23, University of Reading24, Stockholm University25, University of Vermont26, Lund University27, University of Bern28, University of Koblenz and Landau29, Jagiellonian University30, Universidad de las Américas Puebla31, University of California, Davis32
TL;DR: Overall, wild insects pollinated crops more effectively; an increase in wild insect visitation enhanced fruit set by twice as much as an equivalent increase in honey bee visitation.
Abstract: The diversity and abundance of wild insect pollinators have declined in many agricultural landscapes. Whether such declines reduce crop yields, or are mitigated by managed pollinators such as honey bees, is unclear. We found universally positive associations of fruit set with flower visitation by wild insects in 41 crop systems worldwide. In contrast, fruit set increased significantly with flower visitation by honey bees in only 14% of the systems surveyed. Overall, wild insects pollinated crops more effectively; an increase in wild insect visitation enhanced fruit set by twice as much as an equivalent increase in honey bee visitation. Visitation by wild insects and honey bees promoted fruit set independently, so pollination by managed honey bees supplemented, rather than substituted for, pollination by wild insects. Our results suggest that new practices for integrated management of both honey bees and diverse wild insect assemblages will enhance global crop yields.
1,881 citations
Lincoln Park Zoo1, University of Maryland, College Park2, University of California, Davis3, University of Vermont4, Rutgers University5, Swedish University of Agricultural Sciences6, Lüneburg University7, University of Queensland8, University of Pretoria9, Commonwealth Scientific and Industrial Research Organisation10, Cornell University11, University of Göttingen12, Simon Fraser University13, University of Wisconsin-Madison14, National Scientific and Technical Research Council15, University of Würzburg16, Michigan State University17, University of Texas at Austin18, Hebrew University of Jerusalem19, University of Reading20, Lund University21, Federal University of Bahia22, University of California, Berkeley23
TL;DR: This synthesis reveals that pollinator persistence will depend on both the maintenance of high-quality habitats around farms and on local management practices that may offset impacts of intensive monoculture agriculture.
Abstract: Bees provide essential pollination services that are potentially affected both by local farm management and the surrounding landscape. To better understand these different factors, we modelled the relative effects of landscape composition (nesting and floral resources within foraging distances), landscape configuration (patch shape, interpatch connectivity and habitat aggregation) and farm management (organic vs. conventional and local-scale field diversity), and their interactions, on wild bee abundance and richness for 39 crop systems globally. Bee abundance and richness were higher in diversified and organic fields and in landscapes comprising more high-quality habitats; bee richness on conventional fields with low diversity benefited most from high-quality surrounding land cover. Landscape configuration effects were weak. Bee responses varied slightly by biome. Our synthesis reveals that pollinator persistence will depend on both the maintenance of high-quality habitats around farms and on local management practices that may offset impacts of intensive monoculture agriculture.
904 citations
University of Arizona1, Washington State University2, The Nature Conservancy3, University of California, Berkeley4, University of Göttingen5, Wageningen University and Research Centre6, Swedish University of Agricultural Sciences7, University of Idaho8, University of Brasília9, University of Lisbon10, University of California, Davis11, Rutgers University12, Lund University13, Stanford University14, Cornell University15, University of Kiel16, Simon Fraser University17, Federal University of Ceará18, University of Otago19, University of Wisconsin-Madison20, University of Würzburg21, Michigan State University22, University of Turin23, University of Texas at Austin24, Stockholm University25, University of Freiburg26, University of California, Santa Cruz27, Commonwealth Scientific and Industrial Research Organisation28, University of Bristol29, Alberta Environment30, University of North Dakota31, Research Institute of Organic Agriculture32, Spanish National Research Council33, University of Reading34, University of Puerto Rico35, Charles Sturt University36, AgResearch37, University of California, San Francisco38, Technische Universität München39
TL;DR: Both organic farming and in-field plant diversification exerted the strongest effects on pollinators and predators, suggesting these management schemes can facilitate ecosystem service providers without augmenting herbivore (pest) populations.
Abstract: Agricultural intensification is a leading cause of global biodiversity loss, which can reduce the provisioning of ecosystem services in managed ecosystems. Organic farming and plant diversification are farm management schemes that may mitigate potential ecological harm by increasing species richness and boosting related ecosystem services to agroecosystems. What remains unclear is the extent to which farm management schemes affect biodiversity components other than species richness, and whether impacts differ across spatial scales and landscape contexts. Using a global metadataset, we quantified the effects of organic farming and plant diversification on abundance, local diversity (communities within fields), and regional diversity (communities across fields) of arthropod pollinators, predators, herbivores, and detritivores. Both organic farming and higher in-field plant diversity enhanced arthropod abundance, particularly for rare taxa. This resulted in increased richness but decreased evenness. While these responses were stronger at local relative to regional scales, richness and abundance increased at both scales, and richness on farms embedded in complex relative to simple landscapes. Overall, both organic farming and in-field plant diversification exerted the strongest effects on pollinators and predators, suggesting these management schemes can facilitate ecosystem service providers without augmenting herbivore (pest) populations. Our results suggest that organic farming and plant diversification promote diverse arthropod metacommunities that may provide temporal and spatial stability of ecosystem service provisioning. Conserving diverse plant and arthropod communities in farming systems therefore requires sustainable practices that operate both within fields and across landscapes.
235 citations
National University of Río Negro1, Spanish National Research Council2, Swedish University of Agricultural Sciences3, University of Freiburg4, Commonwealth Scientific and Industrial Research Organisation5, National University of Comahue6, University of Reading7, University of Brasília8, University of Leeds9, Naturalis10, University of California, Berkeley11, University of Koblenz and Landau12, University of Bern13, National University of Tucumán14, Federal University of Ceará15, University of Würzburg16, University of Göttingen17, Lund University18, University of Hamburg19, ETH Zurich20, University of Queensland21, Cornell University22, University of Vermont23, Central University of Kerala24, Universidad de las Américas Puebla25, Federal University of Bahia26, Jagiellonian University27
TL;DR: Pollinator species with traits matching those of the focal crop, as well as the enhancement of pollinator richness and evenness, will increase crop yield beyond current practices, and field practitioners can predict and manage agroecosystems for pollination services based on knowledge of just a few traits that are known for a wide range of flower visitor species.
Abstract: Fil: Garibaldi, Lucas Alejandro. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina. Universidad Nacional de Rio Negro. Sede Andina; Argentina
140 citations
TL;DR: Blue vane traps were found to be the most effective trap type, with significantly higher rates of per-sample species accumulation than all other traps, and species richness estimates were highest for the blue vane and blue pan traps.
Abstract: Bees are important pollinators of numerous crops, and monitoring their abundance and diversity in commercial agricultural ecosystems is of increasing importance due to pollinator declines. In season-long field studies conducted in Pennsylvania during 2011–2013, we evaluated five different bee monitoring passive traps—three pan traps (blue, yellow, and white) and two vane traps (blue and yellow)—for their effectiveness and utility for monitoring bees in commercial apple orchards. Traps were placed prebloom and were monitored weekly until the end of crop season (mid-October). We recorded 14,770 bees comprising 118 species, 27 genera, and five families. The most abundant species were Augochlora pura (Say) (34.4% of total), Ceratina calcarata Robertson (15.5%), Bombus vagans Smith (7.8%), Bombus impatiens Cresson (6.4%), and Apis mellifera L. (4.3%). Bee abundance was highly variable among trap types across the three years and during the bloom and postbloom period. Blue vane traps were found to be the most effective trap type, with significantly higher rates of per-sample species accumulation than all other traps. Species richness estimates were highest for the blue vane and blue pan traps. This study reveals the utility and effectiveness of various traps for studying abundance and diversity of pollinator bees in commercially managed apple orchards. It also provides baseline information about the bee community found during the bloom and postbloom periods in Pennsylvania apple orchards that can be used to measure changes in bee community structure and abundance due to conservation efforts, such as reduced risk IPM programs, habitat management, and augmentation.
72 citations
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TL;DR: The stresses bees are experiencing from climate change, infectious diseases, and insecticides are reviewed, with concern that the authors may be nearing a “pollination crisis” in which crop yields begin to fall.
Abstract: Bees are subject to numerous pressures in the modern world. The abundance and diversity of flowers has declined, bees are chronically exposed to cocktails of agrochemicals, and they are simultaneously exposed to novel parasites accidentally spread by humans. Climate change is likely to exacerbate these problems in the future. Stressors do not act in isolation; for example pesticide exposure can impair both detoxification mechanisms and immune responses, rendering bees more susceptible to parasites. It seems certain that chronic exposure to multiple, interacting stressors is driving honey bee colony losses and declines of wild pollinators, but such interactions are not addressed by current regulatory procedures and studying these interactions experimentally poses a major challenge. In the meantime, taking steps to reduce stress on bees would seem prudent; incorporating flower-rich habitat into farmland, reducing pesticide use through adopting more sustainable farming methods, and enforcing effective quarantine measures on bee movements are all practical measures that should be adopted. Effective monitoring of wild pollinator populations is urgently needed to inform management strategies into the future.
2,526 citations
TL;DR: There are well-documented declines in some wild and managed pollinators in several regions of the world, however, many effective policy and management responses can be implemented to safeguard pollinators and sustain pollination services.
Abstract: Wild and managed pollinators provide a wide range of benefits to society in terms of contributions to food security, farmer and beekeeper livelihoods, social and cultural values, as well as the maintenance of wider biodiversity and ecosystem stability. Pollinators face numerous threats, including changes in land-use and management intensity, climate change, pesticides and genetically modified crops, pollinator management and pathogens, and invasive alien species. There are well-documented declines in some wild and managed pollinators in several regions of the world. However, many effective policy and management responses can be implemented to safeguard pollinators and sustain pollination services.
1,121 citations
TL;DR: Although organic agriculture has an untapped role to play when it comes to the establishment of sustainable farming systems, no single approach will safely feed the planet and a blend of organic and other innovative farming systems is needed.
Abstract: Organic agriculture has a history of being contentious and is considered by some as an inefficient approach to food production. Yet organic foods and beverages are a rapidly growing market segment in the global food industry. Here, we examine the performance of organic farming in light of four key sustainability metrics: productivity, environmental impact, economic viability and social wellbeing. Organic farming systems produce lower yields compared with conventional agriculture. However, they are more profitable and environmentally friendly, and deliver equally or more nutritious foods that contain less (or no) pesticide residues, compared with conventional farming. Moreover, initial evidence indicates that organic agricultural systems deliver greater ecosystem services and social benefits. Although organic agriculture has an untapped role to play when it comes to the establishment of sustainable farming systems, no single approach will safely feed the planet. Rather, a blend of organic and other innovative farming systems is needed. Significant barriers exist to adopting these systems, however, and a diversity of policy instruments will be required to facilitate their development and implementation.
959 citations
TL;DR: It is shown that a commonly used insecticide seed coating in a flowering crop can have serious consequences for wild bees, and the contribution of pesticides to the global decline of wild bees may have been underestimated.
Abstract: Understanding the effects of neonicotinoid insecticides on bees is vital because of reported declines in bee diversity and distribution and the crucial role bees have as pollinators in ecosystems and agriculture. Neonicotinoids are suspected to pose an unacceptable risk to bees, partly because of their systemic uptake in plants, and the European Union has therefore introduced a moratorium on three neonicotinoids as seed coatings in flowering crops that attract bees. The moratorium has been criticized for being based on weak evidence, particularly because effects have mostly been measured on bees that have been artificially fed neonicotinoids. Thus, the key question is how neonicotinoids influence bees, and wild bees in particular, in real-world agricultural landscapes. Here we show that a commonly used insecticide seed coating in a flowering crop can have serious consequences for wild bees. In a study with replicated and matched landscapes, we found that seed coating with Elado, an insecticide containing a combination of the neonicotinoid clothianidin and the non-systemic pyrethroid β-cyfluthrin, applied to oilseed rape seeds, reduced wild bee density, solitary bee nesting, and bumblebee colony growth and reproduction under field conditions. Hence, such insecticidal use can pose a substantial risk to wild bees in agricultural landscapes, and the contribution of pesticides to the global decline of wild bees may have been underestimated. The lack of a significant response in honeybee colonies suggests that reported pesticide effects on honeybees cannot always be extrapolated to wild bees.
812 citations
Wageningen University and Research Centre1, Rutgers University2, Spanish National Research Council3, Naturalis4, University of Leeds5, Institut national de la recherche agronomique6, Michigan State University7, University of Freiburg8, University of California, Berkeley9, University of New England (United States)10, University of Vermont11, University of California, Davis12, National University of Singapore13, Hungarian Academy of Sciences14, University of Göttingen15, Cornell University16, Swedish University of Agricultural Sciences17, Stellenbosch University18, Centre national de la recherche scientifique19, Simon Fraser University20, University of Reading21, University of Würzburg22, Plant & Food Research23, University of Giessen24, University of Texas at Austin25, University of Bern26, Hebrew University of Jerusalem27, Lund University28, Federal University of Bahia29
TL;DR: It is shown that, while the contribution of wild bees to crop production is significant, service delivery is restricted to a limited subset of all known bee species, suggesting that cost-effective management strategies to promote crop pollination should target a different set of species than management Strategies to promote threatened bees.
Abstract: There is compelling evidence that more diverse ecosystems deliver greater benefits to people, and these ecosystem services have become a key argument for biodiversity conservation. However, it is unclear how much biodiversity is needed to deliver ecosystem services in a cost-effective way. Here we show that, while the contribution of wild bees to crop production is significant, service delivery is restricted to a limited subset of all known bee species. Across crops, years and biogeographical regions, crop-visiting wild bee communities are dominated by a small number of common species, and threatened species are rarely observed on crops. Dominant crop pollinators persist under agricultural expansion and many are easily enhanced by simple conservation measures, suggesting that cost-effective management strategies to promote crop pollination should target a different set of species than management strategies to promote threatened bees. Conserving the biological diversity of bees therefore requires more than just ecosystem-service-based arguments.
698 citations