| 1. |
- Ahrenfeldt, E J, et al.
(författare)
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Pollinator communities in strawberry crops - variation at multiple spatial scales.
- 2015
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Ingår i: Bulletin of Entomological Research. - 1475-2670. ; 105:4, s. 497-506
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Tidskriftsartikel (refereegranskat)abstract
- Predicting potential pollination services of wild bees in crops requires knowledge of their spatial distribution within fields. Field margins can serve as nesting and foraging habitats for wild bees and can be a source of pollinators. Regional differences in pollinator community composition may affect this spill-over of bees. We studied how regional and local differences affect the spatial distribution of wild bee species richness, activity-density and body size in crop fields. We sampled bees both from the field centre and at two different types of semi-natural field margins, grass strips and hedges, in 12 strawberry fields. The fields were distributed over four regions in Northern Europe, representing an almost 1100 km long north-south gradient. Even over this gradient, daytime temperatures during sampling did not differ significantly between regions and did therefore probably not impact bee activity. Bee species richness was higher in field margins compared with field centres independent of field size. However, there was no difference between centre and margin in body-size or activity-density. In contrast, bee activity-density increased towards the southern regions, whereas the mean body size increased towards the north. In conclusion, our study revealed a general pattern across European regions of bee diversity, but not activity-density, declining towards the field interior which suggests that the benefits of functional diversity of pollinators may be difficult to achieve through spill-over effects from margins to crop. We also identified dissimilar regional patterns in bee diversity and activity-density, which should be taken into account in conservation management.
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| 2. |
- Dainese, Matteo, et al.
(författare)
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A global synthesis reveals biodiversity-mediated benefits for crop production
- 2019
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Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 5:10
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Tidskriftsartikel (refereegranskat)abstract
- Human land use threatens global biodiversity and compromises multiple ecosystem functions critical to food production. Whether crop yield-related ecosystem services can be maintained by a few dominant species or rely on high richness remains unclear. Using a global database from 89 studies (with 1475 locations), we partition the relative importance of species richness, abundance, and dominance for pollination; biological pest control; and final yields in the context of ongoing land-use change. Pollinator and enemy richness directly supported ecosystem services in addition to and independent of abundance and dominance. Up to 50% of the negative effects of landscape simplification on ecosystem services was due to richness losses of service-providing organisms, with negative consequences for crop yields. Maintaining the biodiversity of ecosystem service providers is therefore vital to sustain the flow of key agroecosystem benefits to society. Copyright © 2019 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).
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| 3. |
- Ekroos, Johan, et al.
(författare)
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Sparing land for biodiversity at multiple spatial scales
- 2016
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Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media SA. - 2296-701X. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- A common approach to the conservation of farmland biodiversity and the promotion of multifunctional landscapes, particularly in landscapes containing only small remnants of non-crop habitats, has been to maintain landscape heterogeneity and reduce land-use intensity. In contrast, it has recently been shown that devoting specific areas of non-crop habitats to conservation, segregated from high-yielding farmland (“land sparing”), can more effectively conserve biodiversity than promoting low-yielding, less intensively managed farmland occupying larger areas (“land sharing”). In the present paper we suggest that the debate over the relative merits of land sparing or land sharing is partly blurred by the differing spatial scales at which it is suggested that land sparing should be applied. We argue that there is no single correct spatial scale for segregating biodiversity protection and commodity production in multifunctional landscapes. Instead we propose an alternative conceptual construct, which we call “multiple-scale land sparing,” targeting biodiversity and ecosystem services in transformed landscapes. We discuss how multiple-scale land sparing may overcome the apparent dichotomy between land sharing and land sparing and help to find acceptable compromises that conserve biodiversity and landscape multifunctionality.
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| 4. |
- Garibaldi, Lucas A., et al.
(författare)
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Trait matching of flower visitors and crops predicts fruit set better than trait diversity
- 2015
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Ingår i: Journal of Applied Ecology. - : Wiley. - 1365-2664 .- 0021-8901. ; 52:6, s. 1436-1444
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Forskningsöversikt (refereegranskat)abstract
- Understanding the relationships between trait diversity, species diversity and ecosystem functioning is essential for sustainable management. For functions comprising two trophic levels, trait matching between interacting partners should also drive functioning. However, the predictive ability of trait diversity and matching is unclear for most functions, particularly for crop pollination, where interacting partners did not necessarily co-evolve. World-wide, we collected data on traits of flower visitors and crops, visitation rates to crop flowers per insect species and fruit set in 469 fields of 33 crop systems. Through hierarchical mixed-effects models, we tested whether flower visitor trait diversity and/or trait matching between flower visitors and crops improve the prediction of crop fruit set (functioning) beyond flower visitor species diversity and abundance. Flower visitor trait diversity was positively related to fruit set, but surprisingly did not explain more variation than flower visitor species diversity. The best prediction of fruit set was obtained by matching traits of flower visitors (body size and mouthpart length) and crops (nectar accessibility of flowers) in addition to flower visitor abundance, species richness and species evenness. Fruit set increased with species richness, and more so in assemblages with high evenness, indicating that additional species of flower visitors contribute more to crop pollination when species abundances are similar.Synthesis and applications. Despite contrasting floral traits for crops world-wide, only the abundance of a few pollinator species is commonly managed for greater yield. Our results suggest that the identification and enhancement of 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. Furthermore, we show that 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. Despite contrasting floral traits for crops world-wide, only the abundance of a few pollinator species is commonly managed for greater yield. Our results suggest that the identification and enhancement of 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. Furthermore, we show that 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. Editor's Choice
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| 5. |
- Herbertsson, Lina, et al.
(författare)
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Assessing the risk of stigma clogging in strawberry flowers due to pollinator sharing with oilseed rape
- 2017
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Ingår i: Journal of Pollination Ecology. - 1920-7603. ; 21:2, s. 71-77
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Tidskriftsartikel (refereegranskat)abstract
- Strawberry and oilseed rape are economically important and co-flowering insect-pollinated crops that may affect each other via shared pollinators. One potential negative effect of pollinator sharing is stigma clogging, i.e. that pollen from one plant species covers the stigma and prevents pollination in the other. We tested if application of oilseed rape pollen on strawberry receptacles reduces pollination with subsequent effects on strawberry weight, number of malformations and ripening time. We simulated real pollination situations by using dead bees mounted on toothpicks to mimic flower-visitation of foraging bees. Six strawberry flowers, usually on different plant individuals, were hand-pollinated sequentially per simulated foraging bout. In half of these foraging bouts, we started with an oilseed rape flower, and in those foraging bouts the proportion oilseed rape pollen was expected to decline with increasing number of visited strawberry flowers. Oilseed rape pollen had no effect on any of the tested variables. Increasing number of previously visited strawberry flowers in the simulated foraging bout enhanced the number of developed achenes, but this was marginally non-significant when accounting for the total number of achenes. Strawberry weight increased and ripening time decreased with increasing number of pollinated achenes, whereas none of the tested factors had any effect on the number of malformations. Our results have implications for strawberry farmers, because shortened ripening time could reduce the risk of yield loss from pests, diseases and unfavourable weather conditions. In addition, we show that oilseed rape pollen is unlikely to disturb pollination success of strawberry flowers.
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| 6. |
- Herbertsson, Lina, et al.
(författare)
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Seed-coating of rapeseed (Brassica napus) with the neonicotinoid clothianidin affects behaviour of red mason bees (Osmia bicornis) and pollination of strawberry flowers (Fragaria × ananassa)
- 2022
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 17:9 September
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Tidskriftsartikel (refereegranskat)abstract
- Neonicotinoid insecticides applied to flowering crops can have negative impacts on bees, with implications for crop pollination. To assess if exposure to the neonicotinoid clothianidin via a treated crop (rapeseed) affected bee behaviour, pollination performance (to strawberry), and bee reproduction, we provided each of 12 outdoor cages with rapeseed (autumn-sown plants complemented with a few spring-sown plants to extend the flowering period) grown from either clothianidin-treated or untreated (control) seeds, together with strawberry plants and a small population of red mason bees (Osmia bicornis). We expected clothianidin to reduce bee foraging activity, resulting in impaired strawberry pollination and bee reproduction. During the early stage of the experiment, we observed no difference between treatments in the length of entire foraging trips, or the combined number of rapeseed and strawberry flowers that the bees visited during these trips. During the later stage of the experiment, we instead determined the time a female took to visit 10 rapeseed flowers, as a proxy for foraging performance. We found that they were 10% slower in clothianidin cages. Strawberries weighed less in clothianidin cages, suggesting reduced pollination performance, but we were unable to relate this to reduced foraging activity, because the strawberry flowers received equally many visits in the two treatments. Clothianidin-exposed females sealed their nests less often, but offspring number, sex ratio and weight were similar between treatments. Observed effects on bee behaviour appeared by the end of the experiment, possibly because of accumulated effects of exposure, reduced bee longevity, or higher sensitivity of the protocols we used during the later phase of the experiment. Although the lack of a mechanistic explanation calls for interpreting the results with cautiousness, the lower strawberry weight in clothianidin cages highlights the importance of understanding complex effects of plant protection products, which could have wider consequences than those on directly exposed organisms.
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| 7. |
- Horstmann, Svenja, et al.
(författare)
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Traffic intensity and vegetation management affect flower‐visiting insects and their response to resources in road verges
- 2024
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Ingår i: Journal of Applied Ecology. - Chichester : Wiley-Blackwell. - 0021-8901 .- 1365-2664.
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Tidskriftsartikel (refereegranskat)abstract
- Road verges can support high densities of flowers and could therefore provide new opportunities for the conservation of flower-visiting insects. One way of optimizing road verges for vascular plant diversity is to adjust mowing regimes, but to date it is unclear how this affects flower-visiting insects. Furthermore, for mobile organisms like wild bees and butterflies, there is a risk that the benefit of increased habitat quality in road verges is limited by the proximity to traffic, but this is poorly studied. In a crossed study design, we separated mowing time and frequency (early summer and autumn, or only late summer) from road verge habitat classification (valuable for biodiversity according to transport authority, or regular). We did so along a gradient of traffic intensity, to investigate if a mowing regime designed to enhance plant diversity can also benefit wild bees and butterflies, and if traffic limits the conservation potential of road verges. Road verges that were mown only in late summer had higher flower densities, and there was a positive relationship between flower density and wild bee abundance and species richness. Butterfly abundance and species richness only benefitted from a late summer mowing in valuable but not in regular road verges. Traffic intensity had a substantial negative impact on abundance and species richness of wild bees and butterflies. Higher traffic intensities limited the positive relationship between plant and butterfly species richness that we observed at lower traffic intensities. Increasing width of the road verges buffered negative effects of the traffic on wild bee as well as butterfly abundances, and on wild bee species richness. Synthesis and applications. Road verges can play a valuable role for the conservation of wild bees and butterflies, but there is a need to consider both traffic intensity and resource availability when implementing management strategies. To support wild bee and butterfly diversity, we recommend actions to enhance plant species richness and flower resource availability, and to focus these conservation efforts on roads with low traffic intensity, or on wide road verges. © 2024 The Author(s). Journal of Applied Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.
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| 8. |
- Hutchinson, Louise A., et al.
(författare)
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Using ecological and field survey data to establish a national list of the wild bee pollinators of crops
- 2021
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Ingår i: Agriculture, Ecosystems and Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 315
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Tidskriftsartikel (refereegranskat)abstract
- The importance of wild bees for crop pollination is well established, but less is known about which species contribute to service delivery to inform agricultural management, monitoring and conservation. Using sites in Great Britain as a case study, we use a novel qualitative approach combining ecological information and field survey data to establish a national list of crop pollinating bees for four economically important crops (apple, field bean, oilseed rape and strawberry). A traits data base was used to establish potential pollinators, and combined with field data to identify both dominant crop flower visiting bee species and other species that could be important crop pollinators, but which are not presently sampled in large numbers on crops flowers. Whilst we found evidence that a small number of common, generalist species make a disproportionate contribution to flower visits, many more species were identified as potential pollinators, including rare and specialist species. Furthermore, we found evidence of substantial variation in the bee communities of different crops. Establishing a national list of crop pollinators is important for practitioners and policy makers, allowing targeted management approaches for improved ecosystem services, conservation and species monitoring. Data can be used to make recommendations about how pollinator diversity could be promoted in agricultural landscapes. Our results suggest agri-environment schemes need to support a higher diversity of species than at present, notably of solitary bees. Management would also benefit from targeting specific species to enhance crop pollination services to particular crops. Whilst our study is focused upon Great Britain, our methodology can easily be applied to other countries, crops and groups of pollinating insects.
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| 9. |
- Klatt, Björn, et al.
(författare)
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Bee pollination improves crop quality, shelf life and commercial value.
- 2014
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Ingår i: Royal Society of London. Proceedings B. Biological Sciences. - : The Royal Society. - 1471-2954. ; 281:1775
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Tidskriftsartikel (refereegranskat)abstract
- Pollination improves the yield of most crop species and contributes to one-third of global crop production, but comprehensive benefits including crop quality are still unknown. Hence, pollination is underestimated by international policies, which is particularly alarming in times of agricultural intensification and diminishing pollination services. In this study, exclusion experiments with strawberries showed bee pollination to improve fruit quality, quantity and market value compared with wind and self-pollination. Bee-pollinated fruits were heavier, had less malformations and reached higher commercial grades. They had increased redness and reduced sugar-acid-ratios and were firmer, thus improving the commercially important shelf life. Longer shelf life reduced fruit loss by at least 11%. This is accounting for 0.32 billion US$ of the 1.44 billion US$ provided by bee pollination to the total value of 2.90 billion US$ made with strawberry selling in the European Union 2009. The fruit quality and yield effects are driven by the pollination-mediated production of hormonal growth regulators, which occur in several pollination-dependent crops. Thus, our comprehensive findings should be transferable to a wide range of crops and demonstrate bee pollination to be a hitherto underestimated but vital and economically important determinant of fruit quality.
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| 10. |
- Klatt, Björn, et al.
(författare)
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Enhancing crop shelf life with pollination
- 2014
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Ingår i: Agriculture & Food Security. - : Springer Science and Business Media LLC. - 2048-7010. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- Background: Globally, high amounts of food are wasted due to insufficient quality and decay. Although pollination has been shown to increase crop quality, a possible impact on shelf life has not been quantitatively studied. Results: We tested how shelf life, represented by fruit decay, firmness and weight, changes as a function of pollination limitation in two European, commercially important strawberry varieties. Pollination limitation resulted in lower amounts of deformed fruits. Whereas 65% of wind-pollinated fruits were deformed, open pollination resulted in only 20% deformed fruits. During storage, the proportion of decayed fruits increased in relation to the degree of deformation. In the variety Yamaska, 80% of the fruits with high degrees of deformation decayed after four days, whereas in the variety Sonata, all highly deformed fruits had already decayed after three days. Fruit weight decreased independent from the degree of deformation. However, strongest deformations resulted in a generally lower fruit weight in Sonata, whereas in Yamaska, also medium deformed fruits had a lower weight than highly deformed fruits. Effects of deformation on firmness declines were mostly variety dependent. Whereas firmness declined similarly for all degrees of deformation for Yamaska, highly deformed fruits lost firmness fastest in Sonata. Conclusions: Our results suggest that crop pollination has the potential to reduce food loss and waste in pollinated crops and thus to contribute to global food security. However, this relationship between pollination and food waste has so far been almost completely ignored. Future pollination research should therefore focus not only on yield effects but also on crop quality. A more comprehensive understanding of how pollination can benefit global food security should lead to a more efficient crop production to help meeting future food demands.
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| 11. |
- Klatt, Björn, et al.
(författare)
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Flower volatiles, crop varieties and bee responses.
- 2013
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:8
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Tidskriftsartikel (refereegranskat)abstract
- Pollination contributes to an estimated one third of global food production, through both the improvement of the yield and the quality of crops. Volatile compounds emitted by crop flowers mediate plant-pollinator interactions, but differences between crop varieties are still little explored. We investigated whether the visitation of crop flowers is determined by variety-specific flower volatiles using strawberry varieties (Fragaria x ananassa Duchesne) and how this affects the pollination services of the wild bee Osmia bicornis L. Flower volatile compounds of three strawberry varieties were measured via headspace collection. Gas chromatography showed that the three strawberry varieties produced the same volatile compounds but with quantitative differences of the total amount of volatiles and between distinct compounds. Electroantennographic recordings showed that inexperienced females of Osmia bicornis had higher antennal responses to all volatile compounds than to controls of air and paraffin oil, however responses differed between compounds. The variety Sonata was found to emit a total higher level of volatiles and also higher levels of most of the compounds that evoked antennal responses compared with the other varieties Honeoye and Darselect. Sonata also received more flower visits from Osmia bicornis females under field conditions, compared with Honeoye. Our results suggest that differences in the emission of flower volatile compounds among strawberry varieties mediate their attractiveness to females of Osmia bicornis. Since quality and quantity of marketable fruits depend on optimal pollination, a better understanding of the role of flower volatiles in crop production is required and should be considered more closely in crop-variety breeding.
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| 12. |
- Klatt, Björn K., et al.
(författare)
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A trophic cascade causes unexpected ecological interactions across the aquatic–terrestrial interface under extreme weather
- 2022
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Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 2022:5
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Tidskriftsartikel (refereegranskat)abstract
- Trophic cascades in the aquatic environment constitute important mechanisms for improving water quality. However, how the presence or non-presence of these trophic cascades may affect interactions across the aquatic–terrestrial interface remains poorly investigated. Pollinators such as bees may be especially vulnerable to changes in water resource quality induced by trophic cascades. Understanding how aquatic trophic cascades affect bees and pollination becomes even more pressing under ongoing climate change due to increased physiological demands for water under extreme weather events. In a novel field experiment combining terrestrial and aquatic mesocosms, we aimed to test how changes in water quality induced by an aquatic trophic cascade affected foraging and growth of bumblebee colonies as well as foraging of solitary bees. While we expected fish predation to reduce top–down control of zooplankton on phytoplankton and thereby, indirectly, induce increased growth of toxic cyanobacteria, we instead found the trophic cascade to induce the formation of algal surface mats that bumblebees used to access water under a severe heat wave and drought. This access to water was associated with higher bumblebee colony reproductive success, growth and weight compared to control colonies with no trophic cascade induced (and hence no algal surface mats). We also found marginal but non-significant effects on oilseed rape yield, but surprisingly with higher yields in the control treatment where bumblebees could not access water. Our results provide new insights on how aquatic trophic cascades can lead to unpredicted ecological interactions across the aquatic–terrestrial interface facilitated by climate change. Our study highlights the importance of water for the fitness of terrestrial ecosystem service providers under altered environmental conditions.
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| 13. |
- Klatt, Björn K., et al.
(författare)
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Annual flowers strips benefit bumble bee colony growth and reproduction
- 2020
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Ingår i: Biological Conservation. - : Elsevier BV. - 0006-3207. ; 252
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Tidskriftsartikel (refereegranskat)abstract
- Bumble bees are important crop pollinators but are negatively impacted by agricultural intensification and concomitant loss of floral resources. Flower strips can increase the abundance and sometimes the diversity of bumble bees at local scales, but the importance of flower strips for bumble bee populations at larger scales remains poorly understood. We investigated the effect of flower strips on bumble bee colony growth and reproduction at landscape scales. Commercial bumble bee colonies of a native species (Bombus terrestris) were placed and monitored at different distances from flower strips that were sown on existing ecological focus areas (European Common Agricultural Policy) in southern Sweden. Both the average colony growth (weight) and the production of reproductives (drones and queens) were highest for colonies adjacent to flower strips and declined with increasing distance. Colonies close to the flower strip also produced more reproductives per colony weight. Colony foraging activity was negatively related to the distance to flower strips whereas worker size was not affected. Annual flower strips in ecological focus areas benefit bumble bee colonies by increasing foraging success, colony growth and finally boosting sexual reproduction, demonstrating potential benefits for pollination within and between seasons. These effects were spatially limited but extended to foraging ranges of bumble bees. However, effects of increased colony growth on the abundance of foraging bees in the landscape may extend to larger distances because of forager movements within seasons and queen dispersal between seasons, suggesting that voluntary or incentivised collaboration between farmers may be needed to achieve optimal implementation of flower strips.
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| 14. |
- Klatt, Björn K., 1980-, et al.
(författare)
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Seed treatment with clothianidin induces changes in plant metabolism and alters pollinator foraging preferences
- 2023
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Ingår i: Ecotoxicology. - New York, NY : Springer. - 0963-9292 .- 1573-3017. ; 32:10, s. 1247-1256
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Tidskriftsartikel (refereegranskat)abstract
- Neonicotinoids, systemic insecticides that are distributed into all plant tissues and protect against pests, have become a common part of crop production, but can unintentionally also affect non-target organisms, including pollinators. Such effects can be direct effects from insecticide exposure, but neonicotinoids can affect plant physiology, and effects could therefore also be indirectly mediated by changes in plant phenology, attractiveness and nutritional value. Under controlled greenhouse conditions, we tested if seed treatment with the neonicotinoid clothianidin affected oilseed rape’s production of flower resources for bees and the content of the secondary plant products glucosinolates that provide defense against herbivores. Additionally, we tested if seed treatment affected the attractiveness of oilseed rape to flower visiting bumblebees, using outdoor mesocosms. Flowers and leaves of clothianidin-treated plants had different profiles of glucosinolates compared with untreated plants. Bumblebees in mesocosms foraged slightly more on untreated plants. Neither flower timing, flower size nor the production of pollen and nectar differed between treatments, and therefore cannot explain any preference for untreated oilseed rape. We instead propose that this small but significant preference for untreated plants was related to the altered glucosinolate profile caused by clothianidin. Thereby, this study contributes to the understanding of the complex relationships between neonicotinoid-treated crops and pollinator foraging choices, by suggesting a potential mechanistic link by which insecticide treatment can affect insect behavior.
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| 15. |
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| 16. |
- Knapp, Jessica L., et al.
(författare)
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Pollinators, pests and yield—Multiple trade-offs from insecticide use in a mass-flowering crop
- 2022
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Ingår i: Journal of Applied Ecology. - : Wiley. - 0021-8901 .- 1365-2664. ; 59:9, s. 2419-2429
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Tidskriftsartikel (refereegranskat)abstract
- Multiple trade-offs likely occur between pesticide use, pollinators and yield (via crop flowers) in pollinator-dependent, mass-flowering crops (MFCs), causing potential conflict between conservation and agronomic goals. To date, no studies have looked at both outcomes within the same system, meaning win-win solutions for pollinators and yield can only be inferred. Here, we outline a new framework to explore these trade-offs, using red clover (Trifolium pratense) grown for seed production as an example. Specifically, we address how the insecticide thiacloprid affects densities of seed-eating weevils (Protapion spp.), pollination rates, yield, floral resources and colony dynamics of the key pollinator, Bombus terrestris. Thiacloprid did not affect the amount of nectar provided by, or pollinator visitation to, red clover flowers but did reduce weevil density, correlating to increased yield and gross profit. In addition, colonies of B. terrestris significantly increased their weight and reproductive output in landscapes with (compared with without) red clover, regardless of insecticide use. Synthesis and applications. We propose a holistic conceptual framework to explore trade-offs between pollinators, pesticides and yield that we believe to be essential for achieving conservation and agronomic goals. This framework applies to all insecticide-treated mass-flowering crops (MFCs) and can be adapted to include other ecological processes. Trialling the framework in our study system, we found that our focal insecticide, thiacloprid, improved red clover seed yield with no detected effects on its key pollinator, B. terrestris, and that the presence of red clover in the landscape can benefit pollinator populations.
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| 17. |
- Lichtenberg, Elinor M., et al.
(författare)
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A global synthesis of the effects of diversified farming systems on arthropod diversity within fields and across agricultural landscapes
- 2017
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 23:11, s. 4946-4957
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Tidskriftsartikel (refereegranskat)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.
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| 18. |
- Lindström, Sandra A.M., et al.
(författare)
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Crop management affects pollinator attractiveness and visitation in oilseed rape
- 2018
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Ingår i: Basic and Applied Ecology. - : Elsevier BV. - 1439-1791 .- 1618-0089. ; 26, s. 82-88
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Tidskriftsartikel (refereegranskat)abstract
- Ecological intensification of agriculture implies managing ecological processes to improve performance of agricultural systems. However, impacts on relevant ecological functions such as insect pollination from other crop management factors are poorly explored. Pest insects and crop resources such as water availability can directly affect crop yields, but it is unknown if there are indirect effects through effects on insect pollination. With a factorial experiment, we examined how irrigation and control of pollen beetles affected crop attractiveness and pollinator visitation in an open-pollinated spring oilseed rape cultivar. We studied how irrigation and pest control modified the production of flowers and nectar in oilseed rape, and if this in turn affected the flower-visitation of honey bees and bumble bees. Pest control increased the number of oilseed rape flowers by 69%, and the amount of nectar per flower with 36%, but for the latter only in non-irrigated plots. Furthermore, we found higher pollinator densities in plots with reduced pollen beetle densities. Pest control also reduced the number of non-legitimate flower visits, suggesting higher pollination efficiency in plots with reduced pollen beetle densities. We show that crop management affects the value of mass-flowering crops as a resource for pollinating insects. Development of pest control tools that are harmless to pollinators could increase the value of flowering crops as food resources for pollinating insects.
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| 19. |
- Nilsson, Lovisa, et al.
(författare)
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Effects of Flower-Enriched Ecological Focus Areas on Functional Diversity Across Scales
- 2021
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Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media SA. - 2296-701X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Ecological Focus Areas (EFAs) to benefit biodiversity became mandatory in intensively farmed landscapes after the reform of the European Common Agricultural Policy (CAP) in 2013. The implementation of EFAs as uncropped field margins has been criticized as ineffective but created a window of opportunity to test if augmenting them with annual flower strips can benefit biodiversity. In this study, we investigated if annual flower strips on EFAs benefited functional biodiversity in intensively farmed landscapes. To this end we established eleven annual flower strips with a seed mixture targeted for both natural enemies and pollinators, on areas were farmers had planned for EFAs. We determined effects on aphids and their natural enemies in cereal fields close to six of the flower strips, and for solitary bees and wasp close to and in the surroundings of all eleven flower strips. We found that annual flower strips benefited the abundance of hoverfly larvae and possibly also that of solitary bees. However, there were neither any significant effects on natural enemies (other than hoverfly larvae), nor any difference in natural pest control as shown by lack of differences in aphid numbers and parazitation rates. Abundances of solitary bees and wasps in the surrounding landscapes were unaffected, although there was a tendency for more solitary bee cells closer to the strips. We suggest that the critical issue leading to the mostly negative results is the lack of permanent structures to sustain populations of arthropods that in turn can benefit from annual flower strips. Hence, future agri-environmental policies need to carefully consider if and how annual agri-environmental measures should be implemented in intensively managed agricultural landscapes, e.g., by combining them with more permanent structures.
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| 20. |
- Rundlöf, Maj, et al.
(författare)
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Seed coating with a neonicotinoid insecticide negatively affects wild bees.
- 2015
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 521:7550, s. 77-162
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Tidskriftsartikel (refereegranskat)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.
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| 21. |
- Sahlin, Ullrika, et al.
(författare)
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An evaluation of analyses and data collection of winter loss in honey bees in Sweden
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report evaluates current collection and use of data on winter loss in honey bees in Sweden and is a commission from the Swedish Professional BeekepersAssociation. It includes an overview of factors which may influence winter loss in honey bees in Sweden. In Sweden, data on winter loss is collected by twoinstances, the COLOSS survey and the Swedish Beekeepers Association (SBR). We identify several ways to improve his data collection and make it more cost efficient. Several recommendations are provided such as creating a Swedish partnership for bee health which can specify shared goals for winter loss management and identify needs for data and analyses.
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| 22. |
- Senapathi, Deepa, et al.
(författare)
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Wild insect diversity increases inter-annual stability in global crop pollinator communities
- 2021
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Ingår i: Royal Society of London. Proceedings B. Biological Sciences. - : The Royal Society. - 1471-2954 .- 0962-8452. ; 288:1947
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Tidskriftsartikel (refereegranskat)abstract
- While an increasing number of studies indicate that the range, diversity and abundance of many wild pollinators has declined, the global area of pollinator-dependent crops has significantly increased over the last few decades. Crop pollination studies to date have mainly focused on either identifying different guilds pollinating various crops, or on factors driving spatial changes and turnover observed in these communities. The mechanisms driving temporal stability for ecosystem functioning and services, however, remain poorly understood. Our study quantifies temporal variability observed in crop pollinators in 21 different crops across multiple years at a global scale. Using data from 43 studies from six continents, we show that (i) higher pollinator diversity confers greater inter-annual stability in pollinator communities, (ii) temporal variation observed in pollinator abundance is primarily driven by the three-most dominant species, and (iii) crops in tropical regions demonstrate higher inter-annual variability in pollinator species richness than crops in temperate regions. We highlight the importance of recognizing wild pollinator diversity in agricultural landscapes to stabilize pollinator persistence across years to protect both biodiversity and crop pollination services. Short-term agricultural management practices aimed at dominant species for stabilizing pollination services need to be considered alongside longer term conservation goals focussed on maintaining and facilitating biodiversity to confer ecological stability.
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| 23. |
- Stewart, Rebecca I A, et al.
(författare)
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Ecosystem services across the aquatic-terrestrial boundary : Linking ponds to pollination
- 2017
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Ingår i: Basic and Applied Ecology. - : Elsevier BV. - 1439-1791. ; 18, s. 13-20
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Tidskriftsartikel (refereegranskat)abstract
- Many small farmland ponds are built for nutrient retention, the conservation of biodiversity or both, yet they are relatively neglected habitats. For example, little is known about the potential for ponds to influence populations of beneficial terrestrial insects, deliver ecosystem services across the aquatic-terrestrial boundary and affect crop yield in insect-pollinated cash crops.We assessed whether the presence of a pond affects the abundance of pollinators and the quality and quantity of strawberry yield. We compared the abundance of pollinators and the quality and quantity of strawberries between habitats adjacent to the pond, semi-natural terrestrial habitat and field border without semi-natural vegetation (control habitat).We found significantly higher abundances of syrphids and bees next to ponds compared to control habitats. Also, syrphids were significantly more abundant at pond habitats compared to vegetation habitats and a similar tendency, although not significant, was found for the abundance of bees. The quantity and quality of strawberries was significantly higher near the vegetation and pond habitats compared to the control habitats.Our result supports the theory that the presence of semi-natural habitats, in the agricultural landscape benefits both public interest in biodiversity conservation and farmers' interest in crop pollination. These benefits may also come from ponds as semi natural habitats. However, further studies are required to disentangle the effect of the pond per se and the effect of the associated terrestrial vegetation. Teiche werden in der Agrarlandschaft häufig zur Rückhaltung von Nährstoffen oder auch zur Erhaltung der Biodiversität eingerichtet, und dennoch wurden diese als Habitate bisher wenig beachtet. Daher ist kaum bekannt, ob Teiche über die aquatisch-terrestrische Grenze hinaus Ökosystem-Dienstleistungen unterstützen und Populationen nützlicher Insekten und somit landwirtschaftliche Erträge beeinflussen können. Wir untersuchten, ob das Vorhandensein eines Teiches sich auf die Abundanz der Bestäuber und die Qualität und Quantität der Erdbeerernte auswirkt. Wir verglichen die Abundanz der Bestäuber und die Qualität und Quantität von Erdbeeren im semi-natürlichen Habitaten neben Teichen (Teich), in semi-natürlichen terrestrischen Habitaten ohne Teich (Vegetation) und am Feldrand ohne semi-natürliche Habitate (Kontrolle). Wir fanden signifikant höhere Abundanzen von Schwebfliegen und Bienen neben Teichen im Vergleich zu Kontrollen. Schwebfliegen waren signifikant häufiger an Teichen als in semi-natürlichen Habitaten, und eine ähnliche Tendenz, wenn auch nicht signifikant, wurde für die Abundanz der Bienen gefunden. Die Quantität und Qualität der Erdbeeren war in semi-natürlicher Vegetation und an Teichen signifikant höher als in Kontrollen. Unsere Ergebnisse unterstützen die Annahme, dass das Vorhandensein von semi-natürlichen Habitaten in der Agrarlandschaft sowohl den öffentlichen Wunsch nach Erhaltung der Artenvielfalt als auch den Wunsch der Landwirte nach Bestäubung von Nutzpflanzen erfüllt. Allerdings sind weitere Untersuchungen erforderlich, um die Wirkung von Teichen per se und die Wirkung der zugehörigen terrestrischen Vegetation zu entschlüsseln.
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| 24. |
- Van Oystaeyen, Annette, et al.
(författare)
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Short-term lab assessments and microcolonies are insufficient for the risk assessment of insecticides for bees
- 2021
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535. ; 273
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Tidskriftsartikel (refereegranskat)abstract
- Risk assessment studies addressing effects of agrochemicals on bumblebees frequently use microcolonies. These are queenless colonies consisting of workers only in which typically one worker will lay unfertilized male-destined eggs. In the first tier of risk assessment for bees, short-term laboratory experiments (e.g. microcolonies) are used, the results of which will determine whether higher tier (semi-)field experiments are needed. To evaluate the suitability of microcolonies for risk assessment, a direct comparison between different assessment methods for the neonicotinoid pesticides acetamiprid and thiacloprid was made: microcolonies and queenright colonies under short-term laboratory conditions, queenright colonies under long-term laboratory conditions, and queenright colonies under field conditions. Here, we demonstrate that results from microcolonies contradict results from queenright colonies. While thiacloprid negatively impacted gyne production in queenright colonies, it had a positive effect on microcolony size. By contrast, thiacloprid had no significant effect on fitness parameters of queenright colonies under short-term laboratory conditions when mostly workers are produced. These results thus highlight both the need for long term assessments, allowing evaluation of gyne production, and the risk of reaching erroneous conclusions when using microcolonies. The negative effect of thiacloprid on colony fitness was confirmed under field conditions, where thiacloprid affected the production of reproductives, colony weight gain, worker weight, and foraging behaviour. For acetamiprid, a negative trend on colony fitness could only be shown in a field setup. Therefore, field-realistic setups, which allow colonies to forage freely, are most appropriate to assess sublethal effects of pesticides affecting behaviour and learning.
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| 25. |
- Yourstone, Johanna, et al.
(författare)
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Effects of crop and non-crop resources and competition : High importance of trees and oilseed rape for solitary bee reproduction
- 2021
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Ingår i: Biological Conservation. - : Elsevier BV. - 0006-3207. ; 261
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Tidskriftsartikel (refereegranskat)abstract
- To mitigate wild bee declines, it is important to understand the separate and joint effects of parallel losses of semi-natural habitats containing flower resources and increases in transient flower resources provided by mass- flowering crops. Since mobility may affect how bee species cope with these changes, they may also affect competitive interactions and thus community composition. We focused on how the reproduction of the solitary bee Osmia bicornis is impacted by crop and non-crop forage availability, and if any impact is modified by competition with more mobile bumblebees. We placed trap nests for O. bicornis with and without bumblebee colonies as neighbors at 0, 300, and 1000 m distance from nearest oilseed rape field in 12 agricultural land-scapes. We found that O. bicornis benefitted from proximity to oilseed rape, as well as availability of trees and buttercups. O. bicornis mainly collected oak and maple pollen early in the nesting season, and later switched to buttercup and other grassland species. In contrast to our expectations, we found no competition effects from the more mobile bumblebees. Our study demonstrates that availability of pollen from early-flowering trees and mid- season flowers is important for O. bicornis, but that a mass flowering crop still benefits its reproduction, most likely by supplying nectar. These results underline the importance of a high configurational heterogeneity of agricultural landscapes for bees. Management aiming at safeguarding bee populations in intensified agricultural landscapes should ensure availability of different types of flower resources, including woody species, at appropriate spatial and temporal scales.
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| 26. |
- Åhlén, David, 1988-, et al.
(författare)
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Arthropod communities in constructed wetlands: Hydroperiod and wetland morphology affect riparian groups differently.
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Wetland hydrological dynamics often dictate the composition of biological communities found in or near wetlands, either directly or through changes in vegetation composition. However, much remains unknown, particularly regarding how riparian arthropods respond to such dynamics. In this study, we used high-resolution hydrological data, along with grazing management and shoreline vegetation height from 41 constructed wetlands in south-western Sweden to explore flood zone areas, flood frequencies, vegetation and grazing as drivers of the resident arthropod communities. We found group-specific responses to inundation frequencies, where wetlands with higher frequencies had lower abundances of some coleopterans, and tipulids and wetlands with longer low-water table periods contained less trichopterans and heteropterans. However, flood zone area only affected some lycosids that were more abundant in wetlands with intermediately sized flood zones. Shoreline vegetation height also drove group-specific responses, by affecting aranean-, coleopteran- and dipteran abundances, but in different directions. Given the variable responses to wetland hydrological and structural drivers, it seems that wetland arthropod communities would benefit from a high habitat variability.
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| 27. |
- Åhlén, David, 1988-, et al.
(författare)
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Strong effects of shoreline properties but weak effects of grazing on arthropod diversity in constructed wetlands
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- 1. Aquatic-terrestrial transition zones that contain features essential for many species often have high biodiversity. Shallow flood-zone areas and reed beds are indicative for natural wetland habitats, however, how such features affect the native arthropod biodiversity in constructed wetlands is scarcely investigated. 2. We explored the influence from these shoreline features on the resident arthropod diversities and habitat specializations by a broad collection of the riparian arthropod fauna in 68 constructed wetlands in Sweden, as well as studying constitutive wetland shoreline properties and grazing management. 3. Flooded grassland and reed area, along with shoreline slope influenced arthropod diversities, and responses differed between arthropod groups and diversity metrices. Spider trait diversity was greater in wetlands with larger flooded grassland areas, whilst beetle trait diversity was reduced. Spider phylogenetic diversity was greater in wetlands containing larger reed areas and in wetlands with steeper shorelines. However, species richness in predatory flies was greater in wetlands with more gentle shorelines. 4. Grazing management had limited effects on arthropod diversities, however, species richness in wetland specialist and generalist predatory dipterans was greater in absence of grazers in wetlands with greater flooded grasslands areas. 5. Synthesis and applications: As requirements vary considerably among arthropods, care must be taken when constructing and managing wetlands for arthropod biodiversity. The present results suggest wetlands with a varied shoreline, albeit with greater proportions of flood areas, or multiple adjacent wetlands with varying shores in a wetlandscape, would accommodate a more diverse arthropod fauna. According to our results, current grazing management had limited but negative impact on arthropod diversity. Further detailed studies are required to conclude if different stocking rates and practices of grazing management may improve benefits for arthropod biodiversity.
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