@article{ClassenEardleyHempetal.2020,
  author    = {Classen, Alice and Eardley, Connal D. and Hemp, Andreas and Peters, Marcell K. and Peters, Ralph S. and Ssymank, Axel and Steffan-Dewenter, Ingolf},
  title     = {Specialization of plant-pollinator interactions increases with temperature at Mt. Kilimanjaro},
  series = {Ecology and Evolution},
  volume    = {10},
  journal   = {Ecology and Evolution},
  number    = {4},
  doi       = {10.1002/ece3.6056},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-235959},
  pages     = {2182-2195},
  year      = {2020},
  abstract  = {Aim: Species differ in their degree of specialization when interacting with other species, with significant consequences for the function and robustness of ecosystems. In order to better estimate such consequences, we need to improve our understanding of the spatial patterns and drivers of specialization in interaction networks. Methods: Here, we used the extensive environmental gradient of Mt. Kilimanjaro (Tanzania, East Africa) to study patterns and drivers of specialization, and robustness of plant-pollinator interactions against simulated species extinction with standardized sampling methods. We studied specialization, network robustness and other network indices of 67 quantitative plant-pollinator networks consisting of 268 observational hours and 4,380 plant-pollinator interactions along a 3.4 km elevational gradient. Using path analysis, we tested whether resource availability, pollinator richness, visitation rates, temperature, and/or area explain average specialization in pollinator communities. We further linked pollinator specialization to different pollinator taxa, and species traits, that is, proboscis length, body size, and species elevational ranges. Results: We found that specialization decreased with increasing elevation at different levels of biological organization. Among all variables, mean annual temperature was the best predictor of average specialization in pollinator communities. Specialization differed between pollinator taxa, but was not related to pollinator traits. Network robustness against simulated species extinctions of both plants and pollinators was lowest in the most specialized interaction networks, that is, in the lowlands. Conclusions: Our study uncovers patterns in plant-pollinator specialization along elevational gradients. Mean annual temperature was closely linked to pollinator specialization. Energetic constraints, caused by short activity timeframes in cold highlands, may force ectothermic species to broaden their dietary spectrum. Alternatively or in addition, accelerated evolutionary rates might facilitate the establishment of specialization under warm climates. Despite the mechanisms behind the patterns have yet to be fully resolved, our data suggest that temperature shifts in the course of climate change may destabilize pollination networks by affecting network architecture.},
  language  = {en}
}
@article{HaggeMuellerBirkemoeetal.2021,
  author    = {Hagge, Jonas and M{\"u}ller, J{\"o}rg and Birkemoe, Tone and Buse, J{\"o}rn and Christensen, Rune Haubo Bojesen and Gossner, Martin M. and Gruppe, Axel and Heibl, Christoph and Jarzabek-M{\"u}ller, Andrea and Seibold, Sebastian and Siitonen, Juha and Soutinho, Jo{\~a}o Gon{\c{c}}alo and Sverdrup-Thygeson, Anne and Thorn, Simon and Drag, Lukas},
  title     = {What does a threatened saproxylic beetle look like? Modelling extinction risk using a new morphological trait database},
  series = {Journal of Animal Ecology},
  volume    = {90},
  journal   = {Journal of Animal Ecology},
  number    = {8},
  doi       = {10.1111/1365-2656.13512},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-244717},
  pages     = {1934 -- 1947},
  year      = {2021},
  abstract  = {The extinction of species is a non-random process, and understanding why some species are more likely to go extinct than others is critical for conservation efforts. Functional trait-based approaches offer a promising tool to achieve this goal. In forests, deadwood-dependent (saproxylic) beetles comprise a major part of threatened species, but analyses of their extinction risk have been hindered by the availability of suitable morphological traits. To better understand the mechanisms underlying extinction in insects, we investigated the relationships between morphological features and the extinction risk of saproxylic beetles. Specifically, we hypothesised that species darker in colour, with a larger and rounder body, a lower mobility, lower sensory perception and more robust mandibles are at higher risk. We first developed a protocol for morphological trait measurements and present a database of 37 traits for 1,157 European saproxylic beetle species. Based on 13 selected, independent traits characterising aspects of colour, body shape, locomotion, sensory perception and foraging, we used a proportional-odds multiple linear mixed-effects model to model the German Red List categories of 744 species as an ordinal index of extinction risk. Six out of 13 traits correlated significantly with extinction risk. Larger species as well as species with a broad and round body had a higher extinction risk than small, slim and flattened species. Species with short wings had a higher extinction risk than those with long wings. On the contrary, extinction risk increased with decreasing wing load and with higher mandibular aspect ratio (shorter and more robust mandibles). Our study provides new insights into how morphological traits, beyond the widely used body size, determine the extinction risk of saproxylic beetles. Moreover, our approach shows that the morphological characteristics of beetles can be comprehensively represented by a selection of 13 traits. We recommend them as a starting point for functional analyses in the rapidly growing field of ecological and conservation studies of deadwood.},
  language  = {en}
}