@article{KraussGallenbergerSteffanDewenter2011,
  author    = {Krauss, Jochen and Gallenberger, Iris and Steffan-Dewenter, Ingolf},
  title     = {Decreased Functional Diversity and Biological Pest Control in Conventional Compared to Organic Crop Fields},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-69005},
  year      = {2011},
  abstract  = {Organic farming is one of the most successful agri-environmental schemes, as humans benefit from high quality food, farmers from higher prices for their products and it often successfully protects biodiversity. However there is little knowledge if organic farming also increases ecosystem services like pest control. We assessed 30 triticale fields (15 organic vs. 15 conventional) and recorded vascular plants, pollinators, aphids and their predators. Further, five conventional fields which were treated with insecticides were compared with 10 non-treated conventional fields. Organic fields had five times higher plant species richness and about twenty times higher pollinator species richness compared to conventional fields. Abundance of pollinators was even more than one-hundred times higher on organic fields. In contrast, the abundance of cereal aphids was five times lower in organic fields, while predator abundances were three times higher and predator-prey ratios twenty times higher in organic fields, indicating a significantly higher potential for biological pest control in organic fields. Insecticide treatment in conventional fields had only a short-term effect on aphid densities while later in the season aphid abundances were even higher and predator abundances lower in treated compared to untreated conventional fields. Our data indicate that insecticide treatment kept aphid predators at low abundances throughout the season, thereby significantly reducing top-down control of aphid populations. Plant and pollinator species richness as well as predator abundances and predator-prey ratios were higher at field edges compared to field centres, highlighting the importance of field edges for ecosystem services. In conclusion organic farming increases biodiversity, including important functional groups like plants, pollinators and predators which enhance natural pest control. Preventative insecticide application in conventional fields has only short-term effects on aphid densities but long-term negative effects on biological pest control. Therefore conventional farmers should restrict insecticide applications to situations where thresholds for pest densities are reached.},
  subject      = {Landwirtschaft},
  language  = {en}
}
@article{HendriksmaHaertelSteffanDewenter2011,
  author    = {Hendriksma, Harmen P. and H{\"a}rtel, Stephan and Steffan-Dewenter, Ingolf},
  title     = {Testing Pollen of Single and Stacked Insect-Resistant Bt-Maize on In vitro Reared Honey Bee Larvae},
  series = {PLoS One},
  volume    = {6},
  journal   = {PLoS One},
  number    = {12},
  doi       = {10.1371/journal.pone.0028174},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-137803},
  pages     = {e28174},
  year      = {2011},
  abstract  = {The ecologically and economic important honey bee (Apis mellifera) is a key non-target arthropod species in environmental risk assessment (ERA) of genetically modified (GM) crops. Honey bee larvae are directly exposed to transgenic products by the consumption of GM pollen. But most ERA studies only consider responses of adult bees, although Bt-proteins primarily affect the larval phases of target organisms. We adopted an in vitro larvae rearing system, to assess lethal and sublethal effects of Bt-pollen consumption in a standardized eco-toxicological bioassay. The effects of pollen from two Bt-maize cultivars, one expressing a single and the other a total of three Bt-proteins, on the survival and prepupae weight of honey bee larvae were analyzed. The control treatments included pollen from three non-transgenic maize varieties and of Heliconia rostrata. Three days old larvae were fed the realistic exposure dose of 2 mg pollen within the semi-artificial diet. The larvae were monitored over 120 h, until the prepupal stage, where larvae terminate feeding and growing. Neither single nor stacked Bt-maize pollen showed an adverse effect on larval survival and the prepupal weight. In contrast, feeding of H. rostrata pollen caused significant toxic effects. The results of this study indicate that pollen of the tested Bt-varieties does not harm the development of in vitro reared A. mellifera larvae. To sustain the ecosystem service of pollination, Bt-impact on A. mellifera should always be a crucial part of regulatory biosafety assessments. We suggest that our approach of feeding GM pollen on in vitro reared honey bee larvae is well suited of becoming a standard bioassay in regulatory risk assessments schemes of GM crops.},
  language  = {en}
}
@article{KesslerHertelJungkunstetal.2012,
  author    = {Kessler, Michael and Hertel, Dietrich and Jungkunst, Hermann F. and Kluge, J{\"u}rgen and Abrahamczyk, Stefan and Bos, Merijn and Buchori, Damayanti and Gerold, Gerhard and Gradstein, S. Robbert and K{\"o}hler, Stefan and Leuschner, Christoph and Moser, Gerald and Pitopang, Ramadhanil and Saleh, Shahabuddin and Schulze, Christian H. and Sporn, Simone G. and Steffan-Dewenter, Ingolf and Tjitrosoedirdjo, Sri S. and Tscharntke, Teja},
  title     = {Can Joint Carbon and Biodiversity Management in Tropical Agroforestry Landscapes Be Optimized?},
  series = {PLoS One},
  volume    = {7},
  journal   = {PLoS One},
  number    = {10},
  doi       = {10.1371/journal.pone.0047192},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-132016},
  pages     = {e47192},
  year      = {2012},
  abstract  = {Managing ecosystems for carbon storage may also benefit biodiversity conservation, but such a potential 'win-win' scenario has not yet been assessed for tropical agroforestry landscapes. We measured above-and below-ground carbon stocks as well as the species richness of four groups of plants and eight of animals on 14 representative plots in Sulawesi, Indonesia, ranging from natural rainforest to cacao agroforests that have replaced former natural forest. The conversion of natural forests with carbon stocks of 227-362 Mg C ha\(^{-1}\) to agroforests with 82-211 Mg C ha\(^{-1}\) showed no relationships to overall biodiversity but led to a significant loss of forest-related species richness. We conclude that the conservation of the forest-related biodiversity, and to a lesser degree of carbon stocks, mainly depends on the preservation of natural forest habitats. In the three most carbon-rich agroforestry systems, carbon stocks were about 60\% of those of natural forest, suggesting that 1.6 ha of optimally managed agroforest can contribute to the conservation of carbon stocks as much as 1 ha of natural forest. However, agroforestry systems had comparatively low biodiversity, and we found no evidence for a tight link between carbon storage and biodiversity. Yet, potential win-win agroforestry management solutions include combining high shade-tree quality which favours biodiversity with cacao-yield adapted shade levels.},
  language  = {en}
}
@article{CorneliusLeingaertnerHoissetal.2013,
  author    = {Cornelius, Christine and Leing{\"a}rtner, Annette and Hoiss, Bernhard and Krauss, Jochen and Steffan-Dewenter, Ingolf and Menzel, Annette},
  title     = {Phenological response of grassland species to manipulative snowmelt and drought along an altitudinal gradient},
  series = {Journal of Experimental Botany},
  volume    = {64},
  journal   = {Journal of Experimental Botany},
  number    = {1},
  doi       = {10.1093/jxb/ers321},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-126888},
  pages     = {241-251},
  year      = {2013},
  abstract  = {Plant communities in the European Alps are assumed to be highly affected by climate change, as the temperature rise in this region is above the global average. It is predicted that higher temperatures will lead to advanced snowmelt dates and that the number of extreme weather events will increase. The aims of this study were to determine the impacts of extreme climatic events on flower phenology and to assess whether those impacts differed between lower and higher altitudes. In 2010, an experiment simulating advanced and delayed snowmelt as well as a drought event was conducted along an altitudinal transect approximately every 250 m (600-2000 m above sea level) in the Berchtesgaden National Park, Germany. The study showed that flower phenology was strongly affected by altitude; however, there were few effects of the manipulative treatments on flowering. The effects of advanced snowmelt were significantly greater at higher than at lower sites, but no significant difference was found between both altitudinal bands for the other treatments. The response of flower phenology to temperature declined through the season and the length of flowering duration was not significantly influenced by treatments. The stronger effect of advanced snowmelt at higher altitudes may be a response to differences in treatment intensity across the gradient. Consequently, shifts in the date of snowmelt due to global warming may affect species more at higher than at lower altitudes, as changes may be more pronounced at higher altitudes. These data indicate a rather low risk of drought events on flowering phenology in the Bavarian Alps.},
  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{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{HendriksmaKuetingHaerteletal.2013,
  author    = {Hendriksma, Harmen P. and K{\"u}ting, Meike and H{\"a}rtel, Stephan and N{\"a}ther, Astrid and Dohrmann, Anja B. and Steffan-Dewenter, Ingolf and Tebbe, Christoph C.},
  title     = {Effect of Stacked Insecticidal Cry Proteins from Maize Pollen on Nurse Bees (Apis mellifera carnica) and Their Gut Bacteria},
  series = {PLoS ONE},
  volume    = {8},
  journal   = {PLoS ONE},
  number    = {3},
  doi       = {10.1371/journal.pone.0059589},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131025},
  pages     = {e59589},
  year      = {2013},
  abstract  = {Honey bee pollination is a key ecosystem service to nature and agriculture. However, biosafety research on genetically modified crops rarely considers effects on nurse bees from intact colonies, even though they receive and primarily process the largest amount of pollen. The objective of this study was to analyze the response of nurse bees and their gut bacteria to pollen from Bt maize expressing three different insecticidal Cry proteins (Cry1A.105, Cry2Ab2, and Cry3Bb1). Naturally Cry proteins are produced by bacteria (Bacillus thuringiensis). Colonies of Apis mellifera carnica were kept during anthesis in flight cages on field plots with the Bt maize, two different conventionally bred maize varieties, and without cages, 1-km outside of the experimental maize field to allow ad libitum foraging to mixed pollen sources. During their 10-days life span, the consumption of Bt maize pollen had no effect on their survival rate, body weight and rates of pollen digestion compared to the conventional maize varieties. As indicated by ELISA-quantification of Cry1A.105 and Cry3Bb1, more than 98\% of the recombinant proteins were degraded. Bacterial population sizes in the gut were not affected by the genetic modification. Bt-maize, conventional varieties and mixed pollen sources selected for significantly different bacterial communities which were, however, composed of the same dominant members, including Proteobacteria in the midgut and Lactobacillus sp. and Bifidobacterium sp. in the hindgut. Surprisingly, Cry proteins from natural sources, most likely B. thuringiensis, were detected in bees with no exposure to Bt maize. The natural occurrence of Cry proteins and the lack of detectable effects on nurse bees and their gut bacteria give no indication for harmful effects of this Bt maize on nurse honey bees.},
  language  = {en}
}
@article{KellerGrimmerSteffanDewenter2013,
  author    = {Keller, Alexander and Grimmer, Gudrun and Steffan-Dewenter, Ingolf},
  title     = {Diverse Microbiota Identified in Whole Intact Nest Chambers of the Red Mason Bee Osmia bicornis (Linnaeus 1758)},
  series = {PLoS One},
  journal   = {PLoS One},
  doi       = {10.1371/journal.pone.0078296},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-97305},
  year      = {2013},
  abstract  = {Microbial activity is known to have profound impact on bee ecology and physiology, both by beneficial and pathogenic effects. Most information about such associations is available for colony-building organisms, and especially the honey bee. There, active manipulations through worker bees result in a restricted diversity of microbes present within the colony environment. Microbial diversity in solitary bee nests remains unstudied, although their larvae face a very different situation compared with social bees by growing up in isolated compartments. Here, we assessed the microbiota present in nests and pre-adults of Osmia bicornis, the red mason bee, by culture-independent pyrosequencing. We found high bacterial diversity not comparable with honey bee colonies. We identified a variety of bacteria potentially with positive or negative interactions for bee larvae. However, most of the other diverse bacteria present in the nests seem to originate from environmental sources through incorporated nest building material and stored pollen. This diversity of microorganisms may cause severe larval mortality and require specific physiological or symbiotic adaptations against microbial threats. They may however also profit from such a diverse environment through gain of mutualistic partners. We conclude that further studies of microbiota interaction in solitary bees will improve the understanding of fitness components and populations dynamics.},
  language  = {en}
}
@article{BartomeusPottsSteffanDewenteretal.2014,
  author    = {Bartomeus, Ignasi and Potts, Simon G. and Steffan-Dewenter, Ingolf and Vaissiere, Bernard E. and Woyciechowski, Michal and Krewenka, Kristin M. and Tscheulin, Thomas and Roberts, Stuart P. M. and Szentgyoergyi, Hajnalka and Westphal, Catrin and Bommarco, Riccardo},
  title     = {Contribution of insect pollinators to crop yield and quality varies with agricultural intensification},
  series = {PEERJ},
  volume    = {2},
  journal   = {PEERJ},
  number    = {e328},
  issn      = {2167-9843},
  doi       = {10.7717/peerj.328},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-116928},
  year      = {2014},
  abstract  = {Background. Up to 75\% of crop species benefit at least to some degree from animal pollination for fruit or seed set and yield. However, basic information on the level of pollinator dependence and pollinator contribution to yield is lacking for many crops. Even less is known about how insect pollination affects crop quality. Given that habitat loss and agricultural intensification are known to decrease pollinator richness and abundance, there is a need to assess the consequences for different components of crop production. Methods. We used pollination exclusion on flowers or inflorescences on a whole plant basis to assess the contribution of insect pollination to crop yield and quality in four flowering crops (spring oilseed rape, field bean, strawberry, and buckwheat) located in four regions of Europe. For each crop, we recorded abundance and species richness of flower visiting insects in ten fields located along a gradient from simple to heterogeneous landscapes. Results. Insect pollination enhanced average crop yield between 18 and 71\% depending on the crop. Yield quality was also enhanced in most crops. For instance, oilseed rape had higher oil and lower chlorophyll contents when adequately pollinated, the proportion of empty seeds decreased in buckwheat, and strawberries' commercial grade improved; however, we did not find higher nitrogen content in open pollinated field beans. Complex landscapes had a higher overall species richness of wild pollinators across crops, but visitation rates were only higher in complex landscapes for some crops. On the contrary, the overall yield was consistently enhanced by higher visitation rates, but not by higher pollinator richness. 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.},
  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}
}
@article{LeingaertnerHoissKraussetal.2014,
  author    = {Leing{\"a}rtner, Annette and Hoiss, Bernhard and Krauss, Jochen and Steffan-Dewenter, Ingolf},
  title     = {Combined Effects of Extreme Climatic Events and Elevation on Nutritional Quality and Herbivory of Alpine Plants},
  doi       = {10.1371/journal.pone.0093881},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-112812},
  year      = {2014},
  abstract  = {Climatic extreme events can cause the shift or disruption of plant-insect interactions due to altered plant quality, e.g. leaf carbon to nitrogen ratios, and phenology. However, the response of plant-herbivore interactions to extreme events and climatic gradients has been rarely studied, although climatic extremes will increase in frequency and intensity in the future and insect herbivores represent a highly diverse and functionally important group. We set up a replicated climate change experiment along elevational gradients in the German Alps to study the responses of three plant guilds and their herbivory by insects to extreme events (extreme drought, advanced and delayed snowmelt) versus control plots under different climatic conditions on 15 grassland sites. Our results indicate that elevational shifts in CN (carbon to nitrogen) ratios and herbivory depend on plant guild and season. CN ratios increased with altitude for grasses, but decreased for legumes and other forbs. In contrast to our hypotheses, extreme climatic events did not significantly affect CN ratios and herbivory. Thus, our study indicates that nutritional quality of plants and antagonistic interactions with insect herbivores are robust against seasonal climatic extremes. Across the three functional plant guilds, herbivory increased with nitrogen concentrations. Further, increased CN ratios indicate a reduction in nutritional plant quality with advancing season. Although our results revealed no direct effects of extreme climatic events, the opposing responses of plant guilds along elevation imply that competitive interactions within plant communities might change under future climates, with unknown consequences for plant-herbivore interactions and plant community composition.},
  language  = {en}
}
@article{GamezViruesPerovićGossneretal.2015,
  author    = {G{\´a}mez-Viru{\´e}s, Sagrario and Perović, David J. and Gossner, Martin M. and B{\"o}rschig, Carmen and Bl{\"u}thgen, Nico and de Jong, Heike and Simons, Nadja K. and Klein, Alexandra-Maria and Krauss, Jochen and Maier, Gwen and Scherber, Christoph and Steckel, Juliane and Rothenw{\"o}hrer, Christoph and Steffan-Dewenter, Ingolf and Weiner, Christiane N. and Weisser, Wolfgang and Werner, Michael and Tscharntke, Teja and Westphal, Catrin},
  title     = {Landscape simplification filters species traits and drives biotic homogenization},
  series = {Nature Communications},
  volume    = {6},
  journal   = {Nature Communications},
  number    = {8568},
  doi       = {10.1038/ncomms9568},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-141925},
  year      = {2015},
  abstract  = {Biodiversity loss can affect the viability of ecosystems by decreasing the ability of communities to respond to environmental change and disturbances. Agricultural intensification is a major driver of biodiversity loss and has multiple components operating at different spatial scales: from in-field management intensity to landscape-scale simplification. Here we show that landscape-level effects dominate functional community composition and can even buffer the effects of in-field management intensification on functional homogenization, and that animal communities in real-world managed landscapes show a unified response (across orders and guilds) to both landscape-scale simplification and in-field intensification. Adults and larvae with specialized feeding habits, species with shorter activity periods and relatively small body sizes are selected against in simplified landscapes with intense in-field management. Our results demonstrate that the diversity of land cover types at the landscape scale is critical for maintaining communities, which are functionally diverse, even in landscapes where in-field management intensity is high.},
  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{MartinReinekingSeoetal.2015,
  author    = {Martin, Emily A. and Reineking, Bj{\"o}rn and Seo, Bumsuk and Steffan-Dewenter, Ingolf},
  title     = {Pest control of aphids depends on landscape complexity and natural enemy interactions},
  series = {PeerJ},
  volume    = {3},
  journal   = {PeerJ},
  number    = {e1095},
  doi       = {10.7717/peerj.1095},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-148393},
  year      = {2015},
  abstract  = {Aphids are a major concern in agricultural crops worldwide, and control by natural enemies is an essential component of the ecological intensification of agriculture. Although the complexity of agricultural landscapes is known to influence natural enemies of pests, few studies have measured the degree of pest control by different enemy guilds across gradients in landscape complexity. Here, we use multiple natural-enemy exclosures replicated in 18 fields across a gradient in landscape complexity to investigate (1) the strength of natural pest control across landscapes, measured as the difference between pest pressure in the presence and in the absence of natural enemies; (2) the differential contributions of natural enemy guilds to pest control, and the nature of their interactions across landscapes. We show that natural pest control of aphids increased up to six-fold from simple to complex landscapes. In the absence of pest control, aphid population growth was higher in complex than simple landscapes, but was reduced by natural enemies to similar growth rates across all landscapes. The effects of enemy guilds were landscape-dependent. Particularly in complex landscapes, total pest control was supplied by the combined contribution of flying insects and ground-dwellers. Birds had little overall impact on aphid control. Despite evidence for intraguild predation of flying insects by ground-dwellers and birds, the overall effect of enemy guilds on aphid control was complementary. Understanding pest control services at large spatial scales is critical to increase the success of ecological intensification schemes. Our results suggest that, where aphids are the main pest of concern, interactions between natural enemies are largely complementary and lead to a strongly positive effect of landscape complexity on pest control. Increasing the availability of seminatural habitats in agricultural landscapes may thus benefit not only natural enemies, but also the effectiveness of aphid natural pest control.},
  language  = {en}
}
@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{PetersHempAppelhansetal.2016,
  author    = {Peters, Marcell K. and Hemp, Andreas and Appelhans, Tim and Behler, Christina and Classen, Alice and Detsch, Florian and Ensslin, Andreas and Ferger, Stefan W. and Frederiksen, Sara B. and Gebert, Frederike and Haas, Michael and Helbig-Bonitz, Maria and Hemp, Claudia and Kindeketa, William J. and Mwangomo, Ephraim and Ngereza, Christine and Otte, Insa and R{\"o}der, Juliane and Rutten, Gemma and Costa, David Schellenberger and Tardanico, Joseph and Zancolli, Giulia and Deckert, J{\"u}rgen and Eardley, Connal D. and Peters, Ralph S. and R{\"o}del, Mark-Oliver and Schleuning, Matthias and Ssymank, Axel and Kakengi, Victor and Zhang, Jie and B{\"o}hning-Gaese, Katrin and Brandl, Roland and Kalko, Elisabeth K.V. and Kleyer, Michael and Nauss, Thomas and Tschapka, Marco and Fischer, Markus and Steffan-Dewenter, Ingolf},
  title     = {Predictors of elevational biodiversity gradients change from single taxa to the multi-taxa community level},
  series = {Nature Communications},
  volume    = {7},
  journal   = {Nature Communications},
  doi       = {10.1038/ncomms13736},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-169374},
  year      = {2016},
  abstract  = {The factors determining gradients of biodiversity are a fundamental yet unresolved topic in ecology. While diversity gradients have been analysed for numerous single taxa, progress towards general explanatory models has been hampered by limitations in the phylogenetic coverage of past studies. By parallel sampling of 25 major plant and animal taxa along a 3.7 km elevational gradient on Mt. Kilimanjaro, we quantify cross-taxon consensus in diversity gradients and evaluate predictors of diversity from single taxa to a multi-taxa community level. While single taxa show complex distribution patterns and respond to different environmental factors, scaling up diversity to the community level leads to an unambiguous support for temperature as the main predictor of species richness in both plants and animals. Our findings illuminate the influence of taxonomic coverage for models of diversity gradients and point to the importance of temperature for diversification and species coexistence in plant and animal communities.},
  language  = {en}
}
@article{DePalmaAbrahamczykAizenetal.2016,
  author    = {De Palma, Adriana and Abrahamczyk, Stefan and Aizen, Marcelo A. and Albrecht, Matthias and Basset, Yves and Bates, Adam and Blake, Robin J. and Boutin, C{\´e}line and Bugter, Rob and Connop, Stuart and Cruz-L{\´o}pez, Leopoldo and Cunningham, Saul A. and Darvill, Ben and Diek{\"o}tter, Tim and Dorn, Silvia and Downing, Nicola and Entling, Martin H. and Farwig, Nina and Felicioli, Antonio and Fonte, Steven J. and Fowler, Robert and Franzen, Markus Franz{\´e}n and Goulson, Dave and Grass, Ingo and Hanley, Mick E. and Hendrix, Stephen D. and Herrmann, Farina and Herzog, Felix and Holzschuh, Andrea and Jauker, Birgit and Kessler, Michael and Knight, M. E. and Kruess, Andreas and Lavelle, Patrick and Le F{\´e}on, Violette and Lentini, Pia and Malone, Louise A. and Marshall, Jon and Mart{\´i}nez Pach{\´o}n, Eliana and McFrederick, Quinn S. and Morales, Carolina L. and Mudri-Stojnic, Sonja and Nates-Parra, Guiomar and Nilsson, Sven G. and {\"O}ckinger, Erik and Osgathorpe, Lynne and Parra-H, Alejandro and Peres, Carlos A. and Persson, Anna S. and Petanidou, Theodora and Poveda, Katja and Power, Eileen F. and Quaranta, Marino and Quintero, Carolina and Rader, Romina and Richards, Miriam H. and Roulston, T'ai and Rousseau, Laurent and Sadler, Jonathan P. and Samneg{\aa}rd, Ulrika and Schellhorn, Nancy A. and Sch{\"u}epp, Christof and Schweiger, Oliver and Smith-Pardo, Allan H. and Steffan-Dewenter, Ingolf and Stout, Jane C. and Tonietto, Rebecca K. and Tscharntke, Teja and Tylianakis, Jason M. and Verboven, Hans A. F. and Vergara, Carlos H. and Verhulst, Jort and Westphal, Catrin and Yoon, Hyung Joo and Purvis, Andy},
  title     = {Predicting bee community responses to land-use changes: Effects of geographic and taxonomic biases},
  series = {Scientific Reports},
  volume    = {6},
  journal   = {Scientific Reports},
  doi       = {10.1038/srep31153},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-167642},
  pages     = {31153},
  year      = {2016},
  abstract  = {Land-use change and intensification threaten bee populations worldwide, imperilling pollination services. Global models are needed to better characterise, project, and mitigate bees' responses to these human impacts. The available data are, however, geographically and taxonomically unrepresentative; most data are from North America and Western Europe, overrepresenting bumblebees and raising concerns that model results may not be generalizable to other regions and taxa. To assess whether the geographic and taxonomic biases of data could undermine effectiveness of models for conservation policy, we have collated from the published literature a global dataset of bee diversity at sites facing land-use change and intensification, and assess whether bee responses to these pressures vary across 11 regions (Western, Northern, Eastern and Southern Europe; North, Central and South America; Australia and New Zealand; South East Asia; Middle and Southern Africa) and between bumblebees and other bees. Our analyses highlight strong regionally-based responses of total abundance, species richness and Simpson's diversity to land use, caused by variation in the sensitivity of species and potentially in the nature of threats. These results suggest that global extrapolation of models based on geographically and taxonomically restricted data may underestimate the true uncertainty, increasing the risk of ecological surprises.},
  language  = {en}
}
@article{HolzschuhDaineseGonzalezVaroetal.2016,
  author    = {Holzschuh, Andrea and Dainese, Matteo and Gonzalez-Varo, Juan P. and Mudri-Stojnic, Sonja and Riedinger, Verena and Rundl{\"o}f, Maj and Scheper, Jeroen and Wickens, Jennifer B. and Wickens, Victoria J. and Bommarco, Riccardo and Kleijn, David and Potts, Simon G. and Roberts, Stuart P. M. and Smith, Henrik G. and Vil{\`a}, Montserrat and Vujic, Ante and Steffan-Dewenter, Ingolf},
  title     = {Mass-flowering crops dilute pollinator abundance in agricultural landscapes across Europe},
  series = {Ecology Letters},
  volume    = {19},
  journal   = {Ecology Letters},
  number    = {10},
  doi       = {10.1111/ele.12657},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-187356},
  pages     = {1228-1236},
  year      = {2016},
  abstract  = {Mass-flowering crops (MFCs) are increasingly cultivated and might influence pollinator communities in MFC fields and nearby semi-natural habitats (SNHs). Across six European regions and 2 years, we assessed how landscape-scale cover of MFCs affected pollinator densities in 408 MFC fields and adjacent SNHs. In MFC fields, densities of bumblebees, solitary bees, managed honeybees and hoverflies were negatively related to the cover of MFCs in the landscape. In SNHs, densities of bumblebees declined with increasing cover of MFCs but densities of honeybees increased. The densities of all pollinators were generally unrelated to the cover of SNHs in the landscape. Although MFC fields apparently attracted pollinators from SNHs, in landscapes with large areas of MFCs they became diluted. The resulting lower densities might negatively affect yields of pollinator- dependent crops and the reproductive success of wild plants. An expansion of MFCs needs to be accompanied by pollinator-supporting practices in agricultural landscapes.},
  language  = {en}
}
@article{BeerSteffanDewenterHaerteletal.2016,
  author    = {Beer, Katharina and Steffan-Dewenter, Ingolf and H{\"a}rtel, Stephan and Helfrich-F{\"o}rster, Charlotte},
  title     = {A new device for monitoring individual activity rhythms of honey bees reveals critical effects of the social environment on behavior},
  series = {Journal of Comparative Physiology A},
  volume    = {202},
  journal   = {Journal of Comparative Physiology A},
  number    = {8},
  doi       = {10.1007/s00359-016-1103-2},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-188030},
  pages     = {555-565},
  year      = {2016},
  abstract  = {Chronobiological studies of individual activity rhythms in social insects can be constrained by the artificial isolation of individuals from their social context. We present a new experimental set-up that simultaneously measures the temperature rhythm in a queen-less but brood raising mini colony and the walking activity rhythms of singly kept honey bees that have indirect social contact with it. Our approach enables monitoring of individual bees in the social context of a mini colony under controlled laboratory conditions. In a pilot experiment, we show that social contact with the mini colony improves the survival of monitored young individuals and affects locomotor activity patterns of young and old bees. When exposed to conflicting Zeitgebers consisting of a light-dark (LD) cycle that is phase-delayed with respect to the mini colony rhythm, rhythms of young and old bees are socially synchronized with the mini colony rhythm, whereas isolated bees synchronize to the LD cycle. We conclude that the social environment is a stronger Zeitgeber than the LD cycle and that our new experimental set-up is well suited for studying the mechanisms of social entrainment in honey bees.},
  language  = {en}
}