@article{RequierPailletLarocheetal.2019,
  author    = {Requier, Fabrice and Paillet, Yoan and Laroche, Fabienne and Rutschmann, Benjamin and Zhang, Jie and Lombardi, Fabio and Svoboda, Miroslav and Steffan-Dewenter, Ingolf},
  title     = {Contribution of European forests to safeguard wild honeybee populations},
  series = {Conservation Letters},
  volume    = {13},
  journal   = {Conservation Letters},
  number    = {2},
  doi       = {10.1111/conl.12693},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-204407},
  pages     = {e12693},
  year      = {2019},
  abstract  = {Abstract Recent studies reveal the use of tree cavities by wild honeybee colonies in European forests. This highlights the conservation potential of forests for a highly threatened component of the native entomofauna in Europe, but currently no estimate of potential wild honeybee population sizes exists. Here, we analyzed the tree cavity densities of 106 forest areas across Europe and inferred an expected population size of wild honeybees. Both forest and management types affected the density of tree cavities. Accordingly, we estimated that more than 80,000 wild honeybee colonies could be sustained in European forests. As expected, potential conservation hotspots were identified in unmanaged forests, and, surprisingly, also in other large forest areas across Europe. Our results contribute to the EU policy strategy to halt pollinator declines and reveal the potential of forest areas for the conservation of so far neglected wild honeybee populations in Europe.},
  language  = {en}
}
@article{RedlichMartinWendeetal.2018,
  author    = {Redlich, Sarah and Martin, Emily A. and Wende, Beate and Steffan-Dewenter, Ingolf},
  title     = {Landscape heterogeneity rather than crop diversity mediates bird diversity in agricultural landscapes},
  series = {PLoS ONE},
  volume    = {13},
  journal   = {PLoS ONE},
  number    = {8},
  doi       = {10.1371/journal.pone.0200438},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177110},
  pages     = {e0200438},
  year      = {2018},
  abstract  = {Crop diversification has been proposed as farm management tool that could mitigate the externalities of conventional farming while reducing productivity-biodiversity trade-offs. Yet evidence for the acclaimed biodiversity benefits of landscape-level crop diversity is ambiguous. Effects may strongly depend on spatial scale and the level of landscape heterogeneity (e.g. overall habitat diversity). At the same time, contrasting within-taxon responses obscure benefits to specific functional groups (i.e. species with shared characteristics or requirements) if studied at the community level. The objectives of this study were to 1) disentangle the relative effects of crop diversity and landscape heterogeneity on avian species richness across five spatial scales ranging from 250 to 3000 m radii around focal winter wheat fields; and 2) assess whether functional groups (feeding guild, conservation status, habitat preference, nesting behaviour) determine the strength and direction of responses to crop diversity and landscape heterogeneity. In central Germany, 14 landscapes were selected along independent gradients of crop diversity (annual arable crops) and landscape heterogeneity. Bird species richness in each landscape was estimated using four point counts throughout the breeding season. We found no effects of landscape-level crop diversity on bird richness and functional groups. Instead, landscape heterogeneity was strongly associated with increased total bird richness across all spatial scales. In particular, insect-feeding and non-farmland birds were favoured in heterogeneous landscapes, as were species not classified as endangered or vulnerable on the regional Red List. Crop-nesting farmland birds, however, were less species-rich in these landscapes. Accordingly, crop diversification may be less suitable for conserving avian diversity and associated ecosystem services (e.g. biological pest control), although confounding interactions with management intensity need yet to be confirmed. In contrast, enhancement of landscape heterogeneity by increasing perennial habitat diversity, reducing field sizes and the amount of cropland has the potential to benefit overall bird richness. Specialist farmland birds, however, may require more targeted management approaches.},
  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{OtienoKarpatiPetersetal.2023,
  author    = {Otieno, Mark and Karpati, Zsolt and Peters, Marcell K. and Duque, Laura and Schmitt, Thomas and Steffan-Dewenter, Ingolf},
  title     = {Elevated ozone and carbon dioxide affects the composition of volatile organic compounds emitted by Vicia faba (L.) and visitation by European orchard bee (Osmia cornuta)},
  series = {PLoS One},
  volume    = {18},
  journal   = {PLoS One},
  number    = {4},
  doi       = {10.1371/journal.pone.0283480},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-350020},
  year      = {2023},
  abstract  = {Recent studies link increased ozone (O\(_3\)) and carbon dioxide (CO\(_2\)) levels to alteration of plant performance and plant-herbivore interactions, but their interactive effects on plant-pollinator interactions are little understood. Extra floral nectaries (EFNs) are essential organs used by some plants for stimulating defense against herbivory and for the attraction of insect pollinators, e.g., bees. The factors driving the interactions between bees and plants regarding the visitation of bees to EFNs are poorly understood, especially in the face of global change driven by greenhouse gases. Here, we experimentally tested whether elevated levels of O\(_3\) and CO\(_2\) individually and interactively alter the emission of Volatile Organic Compound (VOC) profiles in the field bean plant (Vicia faba, L., Fabaceae), EFN nectar production and EFN visitation by the European orchard bee (Osmia cornuta, Latreille, Megachilidae). Our results showed that O\(_3\) alone had significant negative effects on the blends of VOCs emitted while the treatment with elevated CO\(_2\) alone did not differ from the control. Furthermore, as with O\(_3\) alone, the mixture of O\(_3\) and CO\(_2\) also had a significant difference in the VOCs' profile. O\(_3\) exposure was also linked to reduced nectar volume and had a negative impact on EFN visitation by bees. Increased CO\(_2\) level, on the other hand, had a positive impact on bee visits. Our results add to the knowledge of the interactive effects of O\(_3\) and CO\(_2\) on plant volatiles emitted by Vicia faba and bee responses. As greenhouse gas levels continue to rise globally, it is important to take these findings into consideration to better prepare for changes in plant-insect interactions.},
  language  = {en}
}
@article{NuernbergerSteffanDewenterHaertel2017,
  author    = {N{\"u}rnberger, Fabian and Steffan-Dewenter, Ingolf and H{\"a}rtel, Stephan},
  title     = {Combined effects of waggle dance communication and landscape heterogeneity on nectar and pollen uptake in honey bee colonies},
  series = {PeerJ},
  volume    = {5},
  journal   = {PeerJ},
  number    = {e3441},
  doi       = {10.7717/peerj.3441},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170813},
  year      = {2017},
  abstract  = {The instructive component of waggle dance communication has been shown to increase resource uptake of Apis mellifera colonies in highly heterogeneous resource environments, but an assessment of its relevance in temperate landscapes with different levels of resource heterogeneity is currently lacking. We hypothesized that the advertisement of resource locations via dance communication would be most relevant in highly heterogeneous landscapes with large spatial variation of floral resources. To test our hypothesis, we placed 24 Apis mellifera colonies with either disrupted or unimpaired instructive component of dance communication in eight Central European agricultural landscapes that differed in heterogeneity and resource availability. We monitored colony weight change and pollen harvest as measure of foraging success. Dance disruption did not significantly alter colony weight change, but decreased pollen harvest compared to the communicating colonies by 40\%. There was no general effect of resource availability on nectar or pollen foraging success, but the effect of landscape heterogeneity on nectar uptake was stronger when resource availability was high. In contrast to our hypothesis, the effects of disrupted bee communication on nectar and pollen foraging success were not stronger in landscapes with heterogeneous compared to homogenous resource environments. Our results indicate that in temperate regions intra-colonial communication of resource locations benefits pollen foraging more than nectar foraging, irrespective of landscape heterogeneity. We conclude that the so far largely unexplored role of dance communication in pollen foraging requires further consideration as pollen is a crucial resource for colony development and health.},
  language  = {en}
}
@article{NjovuSteffanDewenterGebertetal.2021,
  author    = {Njovu, Henry K. and Steffan-Dewenter, Ingolf and Gebert, Friederike and Schellenberger Costa, David and Kleyer, Michael and Wagner, Thomas and Peters, Marcell K.},
  title     = {Plant traits mediate the effects of climate on phytophagous beetle diversity on Mt. Kilimanjaro},
  series = {Ecology},
  volume    = {102},
  journal   = {Ecology},
  number    = {12},
  doi       = {10.1002/ecy.3521},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-257343},
  year      = {2021},
  abstract  = {Patterns of insect diversity along elevational gradients are well described in ecology. However, it remains little tested how variation in the quantity, quality, and diversity of food resources influence these patterns. Here we analyzed the direct and indirect effects of climate, food quantity (estimated by net primary productivity), quality (variation in the specific leaf area index, leaf nitrogen to phosphorus and leaf carbon to nitrogen ratio), and food diversity (diversity of leaf traits) on the species richness of phytophagous beetles along the broad elevation and land use gradients of Mt. Kilimanjaro, Tanzania. We sampled beetles at 65 study sites located in both natural and anthropogenic habitats, ranging from 866 to 4,550 m asl. We used path analysis to unravel the direct and indirect effects of predictor variables on species richness. In total, 3,154 phytophagous beetles representing 19 families and 304 morphospecies were collected. We found that the species richness of phytophagous beetles was bimodally distributed along the elevation gradient with peaks at the lowest (˜866 m asl) and upper mid-elevations (˜3,200 m asl) and sharply declined at higher elevations. Path analysis revealed temperature- and climate-driven changes in primary productivity and leaf trait diversity to be the best predictors of changes in the species richness of phytophagous beetles. Species richness increased with increases in mean annual temperature, primary productivity, and with increases in the diversity of leaf traits of local ecosystems. Our study demonstrates that, apart from temperature, the quantity and diversity of food resources play a major role in shaping diversity gradients of phytophagous insects. Drivers of global change, leading to a change of leaf traits and causing reductions in plant diversity and productivity, may consequently reduce the diversity of herbivore assemblages.},
  language  = {en}
}
@techreport{MuellerSchererLorenzenAmmeretal.2022,
  author    = {M{\"u}ller, J{\"o}rg and Scherer-Lorenzen, Michael and Ammer, Christian and Eisenhauer, Nico and Seidel, Dominik and Schuldt, Bernhard and Biedermann, Peter and Schmitt, Thomas and K{\"u}nzer, Claudia and Wegmann, Martin and Cesarz, Simone and Peters, Marcell and Feldhaar, Heike and Steffan-Dewenter, Ingolf and Claßen, Alice and B{\"a}ssler, Claus and von Oheimb, Goddert and Fichtner, Andreas and Thorn, Simon and Weisser, Wolfgang},
  title     = {BETA-FOR: Erh{\"o}hung der strukturellen Diversit{\"a}t zwischen Waldbest{\"a}nden zur Erh{\"o}hung der Multidiversit{\"a}t und Multifunktionalit{\"a}t in Produktionsw{\"a}ldern. Antragstext f{\"u}r die DFG Forschungsgruppe FOR 5375},
  doi       = {10.25972/OPUS-29084},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-290849},
  pages     = {210},
  year      = {2022},
  abstract  = {Der in j{\"u}ngster Zeit beobachtete kontinuierliche Verlust der β-Diversit{\"a}t in {\"O}kosystemen deutet auf homogene Gemeinschaften auf Landschaftsebene hin, was haupts{\"a}chlich auf die steigende Landnutzungsintensit{\"a}t zur{\"u}ckgef{\"u}hrt wird. Biologische Vielfalt ist mit zahlreichen Funktionen und der Stabilit{\"a}t von {\"O}kosystemen verkn{\"u}pft. Es ist daher zu erwarten, dass eine abnehmende β-Diversit{\"a}t auch die Multifunktionalit{\"a}t verringert. Wir kombinieren hier Fachwissen aus der Forstwissenschaft, der {\"O}kologie, der Fernerkundung, der chemischen {\"O}kologie und der Statistik in einem gemeinschaftlichen und experimentellen β-Diversit{\"a}tsdesign, um einerseits die Auswirkungen der Homogenisierung zu bewerten und andererseits Konzepte zu entwickeln, um negative Auswirkungen durch Homogenisierung in W{\"a}ldern r{\"u}ckg{\"a}ngig zu machen. Konkret werden wir uns mit der Frage besch{\"a}ftigen, ob die Verbesserung der strukturellen β-Komplexit{\"a}t (ESBC) in W{\"a}ldern durch Waldbau oder nat{\"u}rliche St{\"o}rungen die Biodiversit{\"a}t und Multifunktionalit{\"a}t in ehemals homogenen Produktionsw{\"a}ldern erh{\"o}hen kann. Unser Ansatz wird m{\"o}gliche Mechanismen hinter den beobachteten Homogenisierungs-Diversit{\"a}ts-Beziehungen identifizieren und zeigen, wie sich diese auf die Multifunktionalit{\"a}t auswirken. An elf Standorten in ganz Deutschland haben wir dazu zwei Waldbest{\"a}nde als zwei kleine "Waldlandschaften" ausgew{\"a}hlt. In einem dieser beiden Best{\"a}nde haben wir ESBC (Enhancement of Structural Beta Complexity)-Behandlungen durchgef{\"u}hrt. Im zweiten, dem Kontrollbestand, werden wir die gleich Anzahl 50x50m Parzellen ohne ESBC einrichten. Auf allen Parzellen werden wir 18 taxonomische Artengruppen aller trophischer Ebenen und 21 {\"O}kosystemfunktionen, einschließlich der wichtigsten Funktionen in W{\"a}ldern der gem{\"a}ßigten Zonen, messen. Der statistische Rahmen wird eine umfassende Analyse der Biodiversit{\"a}t erm{\"o}glichen, indem verschiedenen Aspekte (taxonomische, funktionelle und phylogenetische Vielfalt) auf verschiedenen Skalenebenen (α-, β-, γ-Diversit{\"a}t) quantifiziert werden. Um die Gesamtdiversit{\"a}t zu kombinieren, werden wir das Konzept der Multidiversit{\"a}t auf die 18 Taxa anwenden. Wir werden neue Ans{\"a}tze zur Quantifizierung und Aufteilung der Multifunktionalit{\"a}t auf α- und β-Skalen verwenden und entwickeln. Durch die experimentelle Beschreibung des Zusammenhangs zwischen β-Diversit{\"a}t und Multifunktionalit{\"a}t in einer Reallandschaft wird unsere Forschung einen neuen Weg einschlagen. Dar{\"u}ber hinaus werden wir dazu beitragen, verbesserte Leitlinien f{\"u}r waldbauliche Konzepte und f{\"u}r das Management nat{\"u}rlicher St{\"o}rungen zu entwickeln, um Homogenisierungseffekte der Vergangenheit umzukehren.},
  subject      = {Wald{\"o}kosystem},
  language  = {en}
}
@article{MayrPetersEardleyetal.2020,
  author    = {Mayr, Antonia V. and Peters, Marcell K. and Eardley, Connal D. and Renner, Marion E. and R{\"o}der, Juliane and Steffan-Dewenter, Ingolf},
  title     = {Climate and food resources shape species richness and trophic interactions of cavity-nesting Hymenoptera},
  series = {Journal of Biogeography},
  volume    = {47},
  journal   = {Journal of Biogeography},
  number    = {4},
  doi       = {10.1111/jbi.13753},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-208101},
  pages     = {854-865},
  year      = {2020},
  abstract  = {Aim: Temperature, food resources and top-down regulation by antagonists are considered as major drivers of insect diversity, but their relative importance is poorly understood. Here, we used cavity-nesting communities of bees, wasps and their antagonists to reveal the role of temperature, food resources, parasitism rate and land use as drivers of species richness at different trophic levels along a broad elevational gradient. Location: Mt. Kilimanjaro, Tanzania. Taxon: Cavity-nesting Hymenoptera (Hymenoptera: Apidae, Colletidae, Megachilidae, Crabronidae, Sphecidae, Pompilidae, Vespidae). Methods: We established trap nests on 25 study sites that were distributed over similar large distances in terms of elevation along an elevational gradient from 866 to 1788 m a.s.l., including both natural and disturbed habitats. We quantified species richness and abundance of bees, wasps and antagonists, parasitism rates and flower or arthropod food resources. Data were analysed with generalized linear models within a multi-model inference framework. Results: Elevational species richness patterns changed with trophic level from monotonically declining richness of bees to increasingly humped-shaped patterns for caterpillar-hunting wasps, spider-hunting wasps and antagonists. Parasitism rates generally declined with elevation but were higher for wasps than for bees. Temperature was the most important predictor of both bee and wasp host richness patterns. Antagonist richness patterns were also well predicted by temperature, but in contrast to host richness patterns, additionally by resource abundance and diversity. The conversion of natural habitats through anthropogenic land use, which included biomass removal, agricultural inputs, vegetation structure and percentage of surrounding agricultural habitats, had no significant effects on bee and wasp communities. Main conclusions: Our study underpins the importance of temperature as a main driver of diversity gradients in ectothermic organisms and reveals the increasingly important role of food resources at higher trophic levels. Higher parasitism rates at higher trophic levels and at higher temperatures indicated that the relative importance of bottom-up and top-down drivers of species richness change across trophic levels and may respond differently to future climate change.},
  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{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}
}