| 1. |
- Alejandre, Elizabeth M., et al.
(author)
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Characterization Factors to Assess Land Use Impacts on Pollinator Abundance in Life Cycle Assessment
- 2023
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In: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 57:8, s. 3445-3454
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Journal article (peer-reviewed)abstract
- While wild pollinators play a key role in global food production, their assessment is currently missing from the most commonly used environmental impact assessment method, Life Cycle Assessment (LCA). This is mainly due to constraints in data availability and compatibility with LCA inventories. To target this gap, relative pollinator abundance estimates were obtained with the use of a Delphi assessment, during which 25 experts, covering 16 nationalities and 45 countries of expertise, provided scores for low, typical, and high expected abundance associated with 24 land use categories. Based on these estimates, this study presents a set of globally generic characterization factors (CFs) that allows translating land use into relative impacts to wild pollinator abundance. The associated uncertainty of the CFs is presented along with an illustrative case to demonstrate the applicability in LCA studies. The CFs based on estimates that reached consensus during the Delphi assessment are recommended as readily applicable and allow key differences among land use types to be distinguished. The resulting CFs are proposed as the first step for incorporating pollinator impacts in LCA studies, exemplifying the use of expert elicitation methods as a useful tool to fill data gaps that constrain the characterization of key environmental impacts.
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| 2. |
- B. Lanuza, Jose, et al.
(author)
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Covariation among reproductive traits in flowering plants shapes their interactions with pollinators
- 2023
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In: Functional Ecology. - 0269-8463. ; 37:7, s. 2072-2084
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Journal article (peer-reviewed)abstract
- Globally, plants display enormous variation in life-history strategies and trait combinations. However, evidence suggests that evolutionary and physiological constraints limit the number of plant ecological strategies. Although there have been recent advances in understanding correlations among plant traits, reproductive traits are rarely considered, despite their key role in shaping plant life-history strategies and interactions with pollinators. Here, using a global dataset of 18 reproductive traits for 1506 species, we investigate the reproductive spectrum of flowering plants to identify how it shapes interactions with pollinators. We show that over 50% of all trait variation is explained by the first two reproductive axes, which represent the negative correlation between flower number and flower size, and the negative correlation between autonomous selfing and floral display size. In addition, these reproductive axes were associated with the identity and number of visits of the distinct pollinator guilds. However, reproductive axes explain a relatively small amount of variance in pollinator interactions highlighting the need to incorporate other factors along with reproductive traits to fully explain large-scale patterns of plant–pollinator interactions. Our study identifies the major reproductive trait correlations in flowering plants and their role in shaping plant–pollinator interactions at a macro-ecological scale. These findings emphasise the importance of considering reproductive traits in the global spectrum of plant form and function, and the need to explore beyond floral morphological traits to broaden our understanding of plant–pollinator interactions. Read the free Plain Language Summary for this article on the Journal blog.
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| 3. |
- Bartomeus, Ignasi
(author)
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Biodiversity ensures plant-pollinator phenological synchrony against climate change
- 2013
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In: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 16, s. 1331-1338
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Journal article (peer-reviewed)abstract
- Climate change has the potential to alter the phenological synchrony between interacting mutualists, such as plants and their pollinators. However, high levels of biodiversity might buffer the negative effects of species-specific phenological shifts and maintain synchrony at the community level, as predicted by the biodiversity insurance hypothesis. Here, we explore how biodiversity might enhance and stabilise phenological synchrony between a valuable crop, apple and its native pollinators. We combine 46 years of data on apple flowering phenology with historical records of bee pollinators over the same period. When the key apple pollinators are considered altogether, we found extensive synchrony between bee activity and apple peak bloom due to complementarity among bee species' activity periods, and also a stable trend over time due to differential responses to warming climate among bee species. A simulation model confirms that high biodiversity levels can ensure plant-pollinator phenological synchrony and thus pollination function.
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| 4. |
- Bartomeus, Ignasi, et al.
(author)
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Contribution of insect pollinators to crop yield and quality varies with agricultural intensification
- 2014
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In: PeerJ. - : PeerJ. - 2167-8359. ; 2
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Journal article (peer-reviewed)abstract
- Discussion. For the four crops in this study, there is clear benefit delivered by pollinators on yield quantity and/or quality, but it is not maximized under current agricultural intensification. Honeybees, the most abundant pollinator, might partially compensate the loss of wild pollinators in some areas, but our results suggest the need of landscape-scale actions to enhance wild pollinator populations.
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| 5. |
- Bartomeus, Ignasi
(author)
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Historical changes in northeastern US bee pollinators related to shared ecological traits
- 2013
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In: Proceedings of the National Academy of Sciences. - : Proceedings of the National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 110, s. 4656-4660
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Journal article (peer-reviewed)abstract
- Pollinators such as bees are essential to the functioning of terrestrial ecosystems. However, despite concerns about a global pollinator crisis, long-term data on the status of bee species are limited. We present a long-term study of relative rates of change for an entire regional bee fauna in the northeastern United States, based on >30,000 museum records representing 438 species. Over a 140-y period, aggregate native species richness weakly decreased, but richness declines were significant only for the genus Bombus. Of 187 native species analyzed individually, only three declined steeply, all of these in the genus Bombus. However, there were large shifts in community composition, as indicated by 56% of species showing significant changes in relative abundance over time. Traits associated with a declining relative abundance include small dietary and phenological breadth and large body size. In addition, species with lower latitudinal range boundaries are increasing in relative abundance, a finding that may represent a response to climate change. We show that despite marked increases in human population density and large changes in anthropogenic land use, aggregate native species richness declines were modest outside of the genus Bombus. At the same time, we find that certain ecological traits are associated with declines in relative abundance. These results should help target conservation efforts focused on maintaining native bee abundance and diversity and therefore the important ecosystems services that they provide.
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| 6. |
- Bartomeus, Ignasi
(author)
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Pollinator declines: reconciling scales and implications for ecosystem services
- 2013
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In: F1000Research. - : F1000 Research Ltd. - 2046-1402. ; 2
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Other publication (peer-reviewed)abstract
- Despite the widespread concern about the fate of pollinators and the ecosystem services they deliver, we still have surprisingly scarce scientific data on the magnitude of pollinator declines and its actual contribution to crop pollination and food security. We use recently published data from northeastern North America to show that studies at both the local and regional scales are needed to understand pollinator declines, and that species-specific responses to global change are broadly consistent across scales. Second, we show that bee species that are currently delivering most of the ecosystem services (i.e. crop pollination) are not among the species showing declining trends, but rather appear to thrivein human-dominated landscapes. - See more at: http://f1000research.com/articles/2-146/v1#sthash.7jLf7zFE.dpuf
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| 7. |
- Bartomeus, Ignasi, et al.
(author)
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Pollinators, pests and soil properties interactively shape oilseed rape yield
- 2015
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In: Basic and Applied Ecology. - : Elsevier BV. - 1439-1791 .- 1618-0089. ; 16, s. 737-745
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Journal article (peer-reviewed)abstract
- Pollination, pest control, and soil properties are well known to affect agricultural production. These factors might interactively shape crop yield, but most studies focus on only one of these factors at a time. We used 15 winter oilseed rape (Brass/co napus L.) fields in Sweden to study how variation among fields in pollinator visitation rates, pollen beetle attack rates and soil properties (soil texture, pH and organic carbon) interactively determined crop yield. The fields were embedded in a landscape gradient with contrasting proportions of arable and semi-natural land. In general, pollinator visitation and pest levels were negatively correlated and varied independently of soil properties. This may reflect that above- and below-ground processes react at landscape and local spatial scales, respectively. The above-ground biotic interactions and below-ground abiotic factors interactively affected crop yield. Pollinator visitation was the strongest predictor positively associated with yield. High soil pH also benefited yield, but only at tower pest loads. Surprisingly, high pest loads increased the pollinator benefits for yield. Implementing management plans at different spatial scales can create synergies among above- and below-ground ecosystem processes, hut both scales are needed given that different processes react al different sptitial scales.
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| 8. |
- Bartomeus, Ignasi
(author)
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Understanding Linkage Rules in Plant-Pollinator Networks by Using Hierarchical Models That Incorporate Pollinator Detectability and Plant Traits
- 2013
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In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8
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Journal article (peer-reviewed)abstract
- The analysis of mutualistic networks has become a central tool in answering theoretical and applied questions regarding our understanding of ecological processes. Significant gaps in knowledge do however need to be bridged in order to effectively and accurately be able to describe networks. Main concern are the incorporation of species level information, accounting for sampling limitations and understanding linkage rules. Here I propose a simple method to combine plant pollinator effort-limited sampling with information about plant community to gain understanding of what drives linkage rules, while accounting for possible undetected linkages. I use hierarchical models to estimate the probability of detection of each plant-pollinator interaction in 12 Mediterranean plant-pollinator networks. As it is possible to incorporate plant traits as co-variables in the models, this method has the potential to be used for predictive purposes, such as identifying undetected links among existing species, as well as potential interactions with new plant species. Results show that pollinator detectability is very skewed and usually low. Nevertheless, 84% of the models are enhanced by the inclusion of co-variables, with flower abundance and inflorescence type being the most commonly retained co-variables. The predicted networks increase network Connectance by 13%, but not Nestedness, which is known to be robust to sampling effects. However, 46% of the pollinator interactions in the studied networks comprised a single observation and hence could not be modeled. The hierarchical modeling approach suggested here is highly flexible and can be used on binary or frequency networks, accommodate different observers or include collection day weather variables as confounding factors. An R script is provided for a rapid adoption of this method.
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| 9. |
- Blasi, Maria, et al.
(author)
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Evaluating predictive performance of statistical models explaining wild bee abundance in a mass-flowering crop
- 2021
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In: Ecography. - : Wiley. - 0906-7590 .- 1600-0587. ; 44:4, s. 525-536
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Journal article (peer-reviewed)abstract
- Wild bee populations are threatened by current agricultural practices in many parts of the world, which may put pollination services and crop yields at risk. Loss of pollination services can potentially be predicted by models that link bee abundances with landscape-scale land-use, but there is little knowledge on the degree to which these statistical models are transferable across time and space. This study assesses the transferability of models for wild bee abundance in a mass-flowering crop across space (from one region to another) and across time (from one year to another). The models used existing data on bumblebee and solitary bee abundance in winter oilseed rape fields, together with high-resolution land-use crop-cover and semi-natural habitats data, from studies conducted in five different regions located in four countries (Sweden, Germany, Netherlands and the UK), in three different years (2011, 2012, 2013). We developed a hierarchical model combining all studies and evaluated the transferability using cross-validation. We found that both the landscape-scale cover of mass-flowering crops and permanent semi-natural habitats, including grasslands and forests, are important drivers of wild bee abundance in all regions. However, while the negative effect of increasing mass-flowering crops on the density of the pollinators is consistent between studies, the direction of the effect of semi-natural habitat is variable between studies. The transferability of these statistical models is limited, especially across regions, but also across time. Our study demonstrates the limits of using statistical models in conjunction with widely available land-use crop-cover classes for extrapolating pollinator density across years and regions, likely in part because input variables such as cover of semi-natural habitats poorly capture variability in pollinator resources between regions and years.
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| 10. |
- Carvalheiro, Luisa Gigante, et al.
(author)
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The potential for indirect effects between co-flowering plants via shared pollinators depends on resource abundance, accessibility and relatedness
- 2014
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In: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 17:11, s. 1389-1399
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Journal article (peer-reviewed)abstract
- Co-flowering plant species commonly share flower visitors, and thus have the potential to influence each other's pollination. In this study we analysed 750 quantitative plant-pollinator networks from 28 studies representing diverse biomes worldwide. We show that the potential for one plant species to influence another indirectly via shared pollinators was greater for plants whose resources were more abundant (higher floral unit number and nectar sugar content) and more accessible. The potential indirect influence was also stronger between phylogenetically closer plant species and was independent of plant geographic origin (native vs. non-native). The positive effect of nectar sugar content and phylogenetic proximity was much more accentuated for bees than for other groups. Consequently, the impact of these factors depends on the pollination mode of plants, e.g. bee or fly pollinated. Our findings may help predict which plant species have the greatest importance in the functioning of plant-pollination networks.
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