@article{KleijnWinfreeBartomeusetal.2015,
  author    = {Kleijn, David and Winfree, Rachael and Bartomeus, Ignasi and Carvalheiro, Lu{\´i}sa G. and Henry, Mickael and Isaacs, Rufus and Klein, Alexandra-Maria and Kremen, Claire and M'Gonigle, Leithen K. and Rader, Romina and Ricketts, Taylor H. and Williams, Neal M. and Adamson, Nancy Lee and Ascher, John S. and B{\´a}ldi, Andr{\´a}s and Bat{\´a}ry, P{\´e}ter and Benjamin, Faye and Biesmeijer, Jacobus C. and Blitzer, Eleanor J. and Bommarco, Riccardo and Brand, Mariette R. and Bretagnolle, Vincent and Button, Lindsey and Cariveau, Daniel P. and Chifflet, R{\´e}my and Colville, Jonathan F. and Danforth, Bryan N. and Elle, Elizabeth and Garratt, Michael P. D. and Herzog, Felix and Holzschuh, Andrea and Howlett, Brad G. and Jauker, Frank and Jha, Shalene and Knop, Eva and Krewenka, Kristin M. and Le F{\´e}on, Violette and Mandelik, Yael and May, Emily A. and Park, Mia G. and Pisanty, Gideon and Reemer, Menno and Riedinger, Verena and Rollin, Orianne and Rundl{\"o}f, Maj and Sardi{\~n}as, Hillary S. and Scheper, Jeroen and Sciligo, Amber R. and Smith, Henrik G. and Steffan-Dewenter, Ingolf and Thorp, Robbin and Tscharntke, Teja and Verhulst, Jort and Viana, Blandina F. and Vaissi{\`e}re, Bernard E. and Veldtman, Ruan and Ward, Kimiora L. and Westphal, Catrin and Potts, Simon G.},
  title     = {Delivery of crop pollination services is an insufficient argument for wild pollinator conservation},
  series = {Nature Communications},
  volume    = {6},
  journal   = {Nature Communications},
  number    = {7414},
  doi       = {10.1038/ncomms8414},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-151879},
  year      = {2015},
  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.},
  language  = {en}
}
@article{HolzschuhDormannTscharntkeetal.2013,
  author    = {Holzschuh, Andrea and Dormann, Carsten F. and Tscharntke, Teja and Steffan-Dewenter, Ingolf},
  title     = {Mass-flowering crops enhance wild bee abundance},
  series = {Oecologia},
  volume    = {172},
  journal   = {Oecologia},
  number    = {2},
  doi       = {10.1007/s00442-012-2515-5},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-132149},
  pages     = {477-484},
  year      = {2013},
  abstract  = {Although agricultural habitats can provide enormous amounts of food resources for pollinator species, links between agricultural and (semi-)natural habitats through dispersal and foraging movements have hardly been studied. In 67 study sites, we assessed the interactions between mass-flowering oilseed rape fields and semi-natural grasslands at different spatial scales, and their effects on the number of brood cells of a solitary cavity-nesting bee. The probability that the bee Osmia bicornis colonized trap nests in oilseed rape fields increased from 12 to 59 \% when grassland was nearby, compared to fields isolated from grassland. In grasslands, the number of brood cells of O. bicornis in trap nests was 55 \% higher when adjacent to oilseed rape compared to isolated grasslands. The percentage of oilseed rape pollen in the larval food was higher in oilseed rape fields and grasslands adjacent to oilseed rape than in isolated grasslands. In both oilseed rape fields and grasslands, the number of brood cells was positively correlated with the percentage of oilseed rape pollen in the larval food. We show that mass-flowering agricultural habitats—even when they are intensively managed—can strongly enhance the abundance of a solitary bee species nesting in nearby semi-natural habitats. Our results suggest that positive effects of agricultural habitats have been underestimated and might be very common (at least) for generalist species in landscapes consisting of a mixture of agricultural and semi-natural habitats. These effects might also have—so far overlooked—implications for interspecific competition and mutualistic interactions in semi-natural habitats.},
  language  = {en}
}
@article{HolzschuhDormannTscharntkeetal.2013,
  author    = {Holzschuh, Andrea and Dormann, Carsten F. and Tscharntke, Teja and Steffan-Dewenter, Ingolf},
  title     = {Mass-flowering crops enhance wild bee abundance},
  series = {Oecologia},
  volume    = {172},
  journal   = {Oecologia},
  number    = {2},
  doi       = {dx.doi.org/10.1007/s00442-012-2515-5},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-126852},
  pages     = {447-484},
  year      = {2013},
  abstract  = {Although agricultural habitats can provide enormous amounts of food resources for pollinator species, links between agricultural and (semi-)natural habitats through dispersal and foraging movements have hardly been studied. In 67 study sites, we assessed the interactions between mass-flowering oilseed rape fields and semi-natural grasslands at different spatial scales, and their effects on the number of brood cells of a solitary cavity-nesting bee. The probability that the bee Osmia bicornis colonized trap nests in oilseed rape fields increased from 12 to 59 \% when grassland was nearby, compared to fields isolated from grassland. In grasslands, the number of brood cells of O. bicornis in trap nests was 55 \% higher when adjacent to oilseed rape compared to isolated grasslands. The percentage of oilseed rape pollen in the larval food was higher in oilseed rape fields and grasslands adjacent to oilseed rape than in isolated grasslands. In both oilseed rape fields and grasslands, the number of brood cells was positively correlated with the percentage of oilseed rape pollen in the larval food. We show that mass-flowering agricultural habitats—even when they are intensively managed—can strongly enhance the abundance of a solitary bee species nesting in nearby semi-natural habitats. Our results suggest that positive effects of agricultural habitats have been underestimated and might be very common (at least) for generalist species in landscapes consisting of a mixture of agricultural and semi-natural habitats. These effects might also have—so far overlooked—implications for interspecific competition and mutualistic interactions in semi-natural habitats.},
  language  = {en}
}
@article{KlattHolzschuhWestphaletal.2014,
  author    = {Klatt, Bj{\"o}rn K. and Holzschuh, Andrea and Westphal, Catrin and Clough, Yann and Smit, Inga and Pawelzik, Elke and Tscharntke, Teja},
  title     = {Bee pollination improves crop quality, shelf life and commercial value},
  series = {Proceedings of the Royal Society B: Biological Sciences},
  volume    = {281},
  journal   = {Proceedings of the Royal Society B: Biological Sciences},
  number    = {1775},
  doi       = {10.1098/rspb.2013.2440},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120797},
  year      = {2014},
  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.},
  language  = {en}
}
@article{SickelAnkenbrandGrimmeretal.2015,
  author    = {Sickel, Wiebke and Ankenbrand, Markus J. and Grimmer, Gudrun and Holzschuh, Andrea and H{\"a}rtel, Stephan and Lanzen, Jonathan and Steffan-Dewenter, Ingolf and Keller, Alexander},
  title     = {Increased efficiency in identifying mixed pollen samples by meta-barcoding with a dual-indexing approach},
  series = {BMC Ecology},
  volume    = {15},
  journal   = {BMC Ecology},
  number    = {20},
  doi       = {10.1186/s12898-015-0051-y},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-125730},
  year      = {2015},
  abstract  = {Background Meta-barcoding of mixed pollen samples constitutes a suitable alternative to conventional pollen identification via light microscopy. Current approaches however have limitations in practicability due to low sample throughput and/or inefficient processing methods, e.g. separate steps for amplification and sample indexing. Results We thus developed a new primer-adapter design for high throughput sequencing with the Illumina technology that remedies these issues. It uses a dual-indexing strategy, where sample-specific combinations of forward and reverse identifiers attached to the barcode marker allow high sample throughput with a single sequencing run. It does not require further adapter ligation steps after amplification. We applied this protocol to 384 pollen samples collected by solitary bees and sequenced all samples together on a single Illumina MiSeq v2 flow cell. According to rarefaction curves, 2,000-3,000 high quality reads per sample were sufficient to assess the complete diversity of 95\% of the samples. We were able to detect 650 different plant taxa in total, of which 95\% were classified at the species level. Together with the laboratory protocol, we also present an update of the reference database used by the classifier software, which increases the total number of covered global plant species included in the database from 37,403 to 72,325 (93\% increase). Conclusions This study thus offers improvements for the laboratory and bioinformatical workflow to existing approaches regarding data quantity and quality as well as processing effort and cost-effectiveness. Although only tested for pollen samples, it is furthermore applicable to other research questions requiring plant identification in mixed and challenging samples.},
  language  = {en}
}
@article{BreezeVaissiereBommarcoetal.2014,
  author    = {Breeze, Tom D. and Vaissiere, Bernhard E. and Bommarco, Riccardo and Petanidou, Theodora and Seraphides, Nicos and Kozak, Lajos and Scheper, Jeroen and Biesmeijer, Jacobus C. and Kleijn, David and Gyldenk{\ae}rne, Steen and Moretti, Marco and Holzschuh, Andrea and Steffan-Dewenter, Ingolf and Stout, Jane C. and P{\"a}rtel, Meelis and Zobel, Martin and Potts, Simon G.},
  title     = {Agricultural Policies Exacerbate Honeybee Pollination Service Supply-Demand Mismatches Across Europe},
  series = {PLOS ONE},
  volume    = {9},
  journal   = {PLOS ONE},
  number    = {1},
  issn      = {1932-6203},
  doi       = {10.1371/journal.pone.0082996},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-117692},
  pages     = {e82996},
  year      = {2014},
  abstract  = {Declines in insect pollinators across Europe have raised concerns about the supply of pollination services to agriculture. Simultaneously, EU agricultural and biofuel policies have encouraged substantial growth in the cultivated area of insect pollinated crops across the continent. Using data from 41 European countries, this study demonstrates that the recommended number of honeybees required to provide crop pollination across Europe has risen 4.9 times as fast as honeybee stocks between 2005 and 2010. Consequently, honeybee stocks were insufficient to supply >90\% of demands in 22 countries studied. These findings raise concerns about the capacity of many countries to cope with major losses of wild pollinators and highlight numerous critical gaps in current understanding of pollination service supplies and demands, pointing to a pressing need for further research into this issue.},
  language  = {en}
}
@article{HopfenmuellerSteffanDewenterHolzschuh2014,
  author    = {Hopfenmueller, Sebastian and Steffan-Dewenter, Ingolf and Holzschuh, Andrea},
  title     = {Trait-Specific Responses of Wild Bee Communities to Landscape Composition, Configuration and Local Factors},
  doi       = {10.1371/journal.pone.0104439},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-112872},
  year      = {2014},
  abstract  = {Land-use intensification and loss of semi-natural habitats have induced a severe decline of bee diversity in agricultural landscapes. Semi-natural habitats like calcareous grasslands are among the most important bee habitats in central Europe, but they are threatened by decreasing habitat area and quality, and by homogenization of the surrounding landscape affecting both landscape composition and configuration. In this study we tested the importance of habitat area, quality and connectivity as well as landscape composition and configuration on wild bees in calcareous grasslands. We made detailed trait-specific analyses as bees with different traits might differ in their response to the tested factors. Species richness and abundance of wild bees were surveyed on 23 calcareous grassland patches in Southern Germany with independent gradients in local and landscape factors. Total wild bee richness was positively affected by complex landscape configuration, large habitat area and high habitat quality (i.e. steep slopes). Cuckoo bee richness was positively affected by complex landscape configuration and large habitat area whereas habitat specialists were only affected by the local factors habitat area and habitat quality. Small social generalists were positively influenced by habitat area whereas large social generalists (bumblebees) were positively affected by landscape composition (high percentage of semi-natural habitats). Our results emphasize a strong dependence of habitat specialists on local habitat characteristics, whereas cuckoo bees and bumblebees are more likely affected by the surrounding landscape. We conclude that a combination of large high-quality patches and heterogeneous landscapes maintains high bee species richness and communities with diverse trait composition. Such diverse communities might stabilize pollination services provided to crops and wild plants on local and landscape scales.},
  language  = {en}
}