Yearly fluctuations of flower landscape in a Mediterranean scrubland: Consequences for floral resource availability

(2018) Yearly fluctuations of flower landscape in a Mediterranean scrubland: Consequences for floral resource availability. . : -.
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Doi: https://doi.org/10.1371/journal.pone.0191268

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Loss of pollinators: evidences, causes and consequences [Pérdida de polinizadores: Evidencias, causas y consecuencias]

Bartomeus I., Bosch J. (2018) Loss of pollinators: evidences, causes and consequences [Pérdida de polinizadores: Evidencias, causas y consecuencias]. Ecosistemas. 27: 1-2.
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Doi: 10.7818/ECOS.1542

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[No abstract available]

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Earwigs and woolly apple aphids in integrated and organic apple orchards: responses of a generalist predator and a pest prey to local and landscape factors

Happe A.-K., Roquer-Beni L., Bosch J., Alins G., Mody K. (2018) Earwigs and woolly apple aphids in integrated and organic apple orchards: responses of a generalist predator and a pest prey to local and landscape factors. Agriculture, Ecosystems and Environment. 268: 44-51.
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Doi: 10.1016/j.agee.2018.09.004

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Organic management, connective woody habitats, and landscape complexity are supposed to enhance beneficial arthropods and biological pest control in agro-ecosystems. We studied earwigs (Dermaptera: Forficulidae) as generalist predators and aphids (Hemiptera: Aphididae) as key pests serving as earwig prey in a total of 58 commercial apple orchards differing in management (integrated production (IP) versus organic) in Germany and Spain. We focused on the effects of local agri-environmental structures, orchard management, and composition of the surrounding landscape on earwig populations and on tree infestation by the woolly apple aphid (WAA), Eriosoma lanigerum. Surprisingly, the common earwig, Forficula auricularia, did not benefit from organic management in either country, and we found even slightly higher earwig abundances in IP than in organic orchards in Germany. In Spain, we found a negative impact of IP compared to organic management on abundance of the earwig Forficula pubescens, whereas orchard management did not affect the abundance of F. auricularia. The presence of woody habitats adjacent to the orchard reduced the abundance of F. auricularia in IP but not in organic orchards in Germany. We did not study the effects of woody habitats in Spain, where these structures were very scarce. There was no effect of high plant species richness at the orchard boundary or compositional landscape heterogeneity on earwig abundance in either country. In Germany, WAA infestation was very low and driven by landscape characteristics rather than orchard management. In Spain, WAA infestation differed strongly between management types (higher in organic orchards). There were no strong, consistent correlations between earwig abundance and WAA infestation in either country. Our study shows that adjacent woody structures and orchard management may affect earwigs in perennial cropping systems. The consequences of orchard management, however, seem to strongly depend on earwig species. Our study suggests that woody elements may serve as sink habitats – potentially attracting earwigs by providing alternative prey and shelter – in IP (but not in organic) orchards. © 2018 Elsevier B.V.

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Landscape configurational heterogeneity by small-scale agriculture, not crop diversity, maintains pollinators and plant reproduction in western Europe

Hass A.L., Kormann U.G., Tscharntke T., Clough Y., Baillod A.B., Sirami C., Fahrig L., Martin J.-L., Baudry J., Bertrand C., Bosch J., Brotons L., Bure F., Georges R., Giralt D., Marcos-García M.Á., Ricarte A., Siriwardena G., Batáry P. (2018) Landscape configurational heterogeneity by small-scale agriculture, not crop diversity, maintains pollinators and plant reproduction in western Europe. Proceedings of the Royal Society B: Biological Sciences. 285: 0-0.
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Doi: 10.1098/rspb.2017.2242

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Agricultural intensification is one of the main causes for the current biodiversity crisis. While reversing habitat loss on agricultural land is challenging, increasing the farmland configurational heterogeneity (higher field border density) and farmland compositional heterogeneity (higher crop diversity) has been proposed to counteract some habitat loss. Here, we tested whether increased farmland configurational and compositional heterogeneity promote wild pollinators and plant reproduction in 229 landscapes located in four major western European agricultural regions. High-field border density consistently increased wild bee abundance and seed set of radish (Raphanus sativus), probably through enhanced connectivity. In particular, we demonstrate the importance of crop-crop borders for pollinator movement as an additional experiment showed higher transfer of a pollen analogue along crop-crop borders than across fields or along semi-natural crop borders. By contrast, high crop diversity reduced bee abundance, probably due to an increase of crop types with particularly intensive management. This highlights the importance of crop identity when higher crop diversity is promoted. Our results show that small-scale agricultural systems can boost pollinators and plant reproduction. Agri-environmental policies should therefore aim to halt and reverse the current trend of increasing field sizes and to reduce the amount of crop types with particularly intensive management. © 2018 The Author(s) Published by the Royal Society. All rights reserved.

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Seasonal dynamics in a Cavity-Nesting beewasp community: Shifts in composition, functional diversity and host-parasitoid network structure

Osorio-Canadas S., Arnan X., Bassols E., Vicens N., Bosch J. (2018) Seasonal dynamics in a Cavity-Nesting beewasp community: Shifts in composition, functional diversity and host-parasitoid network structure. PLoS ONE. 13: 0-0.
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Doi: 10.1371/journal.pone.0205854

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Ecological communities are composed of species that interact with each other forming complex interaction networks. Although interaction networks have been usually treated as static entities, interactions show high levels of temporal variation, mainly due to temporal species turnover. Changes in taxonomic composition are likely to bring about changes in functional trait composition. Because functional traits influence the likelihood that two species interact, temporal changes in functional composition and structure may ultimately affect interaction network structure. Here, we study the seasonality (spring vs. summer) in a community of cavity-nesting solitary bees and wasps ('hosts') and their nest associates ('parasitoids'). We analyze seasonal changes in taxonomic compostion and structure, as well as in functional traits, of the host and parasitoid communities. We also analyze whether these changes result in changes in percent parasitism and interaction network structure. Our host and parasitoid communities are strongly seasonal. Host species richness increases from spring to summer. This results in important seasonal changes in functional composition of the host community. The spring community (almost exclusively composed of bees) is characterized by large, univoltine, adult-wintering host species. The summer community (composed of both bees and wasps) is dominated by smaller, bivoltine, prepupa-wintering species. Host functional diversity is higher in summer than in spring. Importantly, these functional changes are not only explained by the addition of wasp species in summer. Functional changes in the parasitoid community are much less pronounced, probably due to the lower parasitoid species turnover. Despite these important taxonomic and functional changes, levels of parasitism did not change across seasons. Two network metrics (generality and interaction evenness) increased from spring to summer. These changes can be explained by the seasonal increase in species richness (and therefore network size). The seasonal shift from a bee-dominated community in spring to a wasp-dominated community in summer suggests a change in ecosystem function, with emphasis on pollination in spring to emphasis on predation in summer. © 2018 Osorio-Canadas et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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