@article{GebertSteffan‐DewenterKronbachetal.2022,
  author    = {Gebert, Friederike and Steffan-Dewenter, Ingolf and Kronbach, Patrick and Peters, Marcell K.},
  title     = {The role of diversity, body size and climate in dung removal: A correlative and experimental approach},
  series = {Journal of Animal Ecology},
  volume    = {91},
  journal   = {Journal of Animal Ecology},
  number    = {11},
  doi       = {10.1111/1365-2656.13798},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-293907},
  pages     = {2181 -- 2191},
  year      = {2022},
  abstract  = {The mechanisms by which climatic changes influence ecosystem functions, that is, by a direct climatic control of ecosystem processes or by modifying richness and trait compositions of species communities, remain unresolved. This study is a contribution to this discourse by elucidating the linkages between climate, land use, biodiversity, body size and ecosystem functions. We disentangled direct climatic from biodiversity-mediated effects by using dung removal by dung beetles as a model system and by combining correlative field data and exclosure experiments along an extensive elevational gradient on Mt. Kilimanjaro, Tanzania. Dung removal declined with increasing elevation, being associated with a strong reduction in the richness and body size traits of dung beetle communities. Climate influenced dung removal rates by modifying biodiversity rather than by direct effects. The biodiversity-ecosystem effect was driven by a change in the mean body size of dung beetles. Dung removal rates were strongly reduced when large dung beetles were experimentally excluded. This study underscores that climate influences ecosystem functions mainly by modifying biodiversity and underpins the important role of body size for dung removal.},
  language  = {en}
}
@article{KrimmerMartinHolzschuhetal.2022,
  author    = {Krimmer, Elena and Martin, Emily A. and Holzschuh, Andrea and Krauss, Jochen and Steffan-Dewenter, Ingolf},
  title     = {Flower fields and pesticide use interactively shape pollen beetle infestation and parasitism in oilseed rape fields},
  series = {Journal of Applied Ecology},
  volume    = {59},
  journal   = {Journal of Applied Ecology},
  number    = {1},
  doi       = {10.1111/1365-2664.14051},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-258037},
  pages     = {263-273},
  year      = {2022},
  abstract  = {Pollen beetles (Brassicogethes spp.) are the main pests of oilseed rape (OSR, Brassica napus) in Europe and responsible for massive yield losses. Upcoming pesticide resistances highlight the need for other means of crop protection, such as natural pest control. Sown flower fields aim to counteract the decrease of insect biodiversity in agricultural landscapes by providing resources to ecosystem service providers. However, the optimal age and size of flower fields to increase natural pest control is still unclear. We conducted experiments on 31 OSR fields located along a gradient of landscape-scale semi-natural habitat (SNH). OSR fields were located adjacent to flower fields which differed in age, continuity and size, or adjacent to crop fields or calcareous grasslands. Pesticide-free areas were established to examine interactive effects of pesticide use and flower field characteristics. The abundance of pollen beetle adults and larvae, parasitism and superparasitism rates in OSR were recorded at increasing distances to the adjacent sites. Flower fields and calcareous grasslands increased pollen beetle parasitism when compared to OSR fields neighbouring crop fields. The threshold for effective natural pest control of 35\% could be reached in the pesticide-free areas of OSR fields adjacent to calcareous grasslands and flower fields maintained continuously for at least 6 years. In pesticide-sprayed areas, pollen beetle parasitism and superparasitism declined with increasing distance to the adjacent field. Furthermore, flower fields larger than 1.5 ha were able to improve pollen beetle parasitism more than smaller fields. Synthesis and applications. To promote natural pest control in oilseed rape (OSR), large flower fields should be maintained for several years, to create stable habitats for natural enemies. The continuous maintenance of flower fields should be preferred, as ploughing and resowing after 5-6 years decreased the positive effects of the flower fields on natural pest control in adjacent OSR fields. However, pesticide use can abrogate positive effects of flower fields on pollen beetle parasitism. This study highlights that sown flower fields have the potential to increase natural pest control in OSR, but this potential is depending on its age, continuity and size and can be hindered by pesticide use.},
  language  = {en}
}
@article{BoetzlSchueleKraussetal.2020,
  author    = {Boetzl, Fabian A. and Schuele, Maren and Krauss, Jochen and Steffan-Dewenter, Ingolf},
  title     = {Pest control potential of adjacent agri-environment schemes varies with crop type and is shaped by landscape context and within-field position},
  series = {Journal of Applied Ecology},
  volume    = {57},
  journal   = {Journal of Applied Ecology},
  number    = {8},
  doi       = {10.1111/1365-2664.13653},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-218265},
  pages     = {1482 -- 1493},
  year      = {2020},
  abstract  = {Increasing natural pest control in agricultural fields is an important aim of ecological intensification. Combined effects of landscape context and local placement of agri-environmental schemes (AES) on natural pest control and within-field distance functions of natural pest control agents have rarely been addressed but might affect the distribution of biocontrol providers. Importantly, it is currently unknown whether ecosystem services provided by adjacent AES are consistent for different crop types during crop rotation. In this study, we assessed whether crop rotation from oilseed rape to cereals altered within-field distance functions of ground-dwelling predators from adjacent agri-environmental fields along a gradient in landscape context. Additionally, we recorded crop pests, predation rates, parasitoids as well as crop yields on a total of 30 study sites. Distance functions varied between trophic levels: Carabid richness decreased while densities of carabid beetles, staphylinid beetles as well as crop yields increased towards the field centres. Distance functions of parasitoids and pests were modulated by the amount of semi-natural habitat in the surrounding landscape, while the effects of adjacent AES were limited. Distance decay functions found for ground-dwelling predators in oilseed rape in the previous year were not always present in cereals. Increasing distance to the field edge also increased effects of crop rotation on carabid beetle assemblages, indicating a source habitat function of field edges. Synthesis and applications. Distance functions of natural pest control are not universal and the effects of agri-environmental schemes (AES) in different adjacent crops during crop rotation vary and depend on ecological contrasts. A network of semi-natural habitats and spatially optimized AES habitats can benefit pest control in agricultural landscapes, but constraints as a result of crop type need to be addressed by annually targeted, spatially shifting agri-environment schemes for different crops.},
  language  = {en}
}