@article{GallUebelEbensenetal.2017, author = {Gall, Andrea and Uebel, Udo and Ebensen, Uwe and Hillebrand, Helmut and Meier, Sandra and Singer, Gabriel and Wacker, Alexander and Striebel, Maren}, title = {Planktotrons}, series = {Limnology and oceanography-methods}, volume = {15}, journal = {Limnology and oceanography-methods}, publisher = {Wiley}, address = {Hoboken}, issn = {1541-5856}, doi = {10.1002/lom3.10196}, pages = {663 -- 677}, year = {2017}, abstract = {We established a new indoor mesocosm facility, 12 fully controlled Planktotrons, designed to conduct marine and freshwater experiments for biodiversity and food web approaches using natural or artificial, benthic or planktonic communities. The Planktotrons are a unique and custom-tailored facility allowing long-term experiments. Wall growth can be inhibited by a rotating gate paddle with silicone lips. Additionally, temperature and light intensity are individually controllable for each Planktotron and the large volume (600 L) enables high-frequency or volume-intense measurements. In a pilot freshwater experiment various trophic levels of a pelagic food web were maintained for up to 90 d. First, an artificially assembled phytoplankton community of 11 species was inoculated in all Planktotrons. After 22 d, two ciliates were added to all, and three Daphnia species were added to six Planktotrons. After 72 d, dissolved organic matter (DOM, an alkaline soil extract) was added as an external disturbance to six of the 12 Planktotrons, involving three Planktotrons stocked with Daphnia and three without, respectively. We demonstrate the suitability of the Planktotrons for food web and biodiversity research. Variation among replicated Planktotrons (n=3 minimum) did not differ from other laboratory systems and field experiments. We investigated population dynamics and interactions among the different trophic levels, and found them affected by the sequence of ciliate and Daphnia addition and the disturbance caused by addition of DOM.}, language = {en} } @article{GerhardKoussoroplisHillebrandetal.2019, author = {Gerhard, Miriam and Koussoroplis, Apostolos Manuel and Hillebrand, Helmut and Striebel, Maren}, title = {Phytoplankton community responses to temperature fluctuations under different nutrient concentrations and stoichiometry}, series = {Ecology : a publication of the Ecological Society of America}, volume = {100}, journal = {Ecology : a publication of the Ecological Society of America}, number = {11}, publisher = {Wiley}, address = {Hoboken}, issn = {0012-9658}, doi = {10.1002/ecy.2834}, pages = {11}, year = {2019}, abstract = {Nutrient availability and temperature are important drivers of phytoplankton growth and stoichiometry. However, the interactive effects of nutrients and temperature on phytoplankton have been analyzed mostly by addressing changes in average temperature, whereas recent evidence suggests an important role of temperature fluctuations. In a laboratory experiment, we grew a natural phytoplankton community under fluctuating and constant temperature regimes across 25 combinations of nitrogen (N) and phosphorus (P) supply. Temperature fluctuations decreased phytoplankton growth rate (r(max)), as predicted by nonlinear averaging along the temperature-growth relationship. r(max) increased with increasing P supply, and a significant temperature x P x N interaction reflected that the shape of the thermal reaction norm depended on nutrients. By contrast, phytoplankton carrying capacity increased with N supply and in fluctuating rather than constant temperature. Higher phytoplankton N:P ratios under constant temperature showed that temperature regimes affected cellular nutrient incorporation. Minor differences in species diversity and composition existed. Our results suggest that temperature variability interacts with nutrient supply to affect phytoplankton physiology and stoichiometry at the community level.}, language = {en} } @article{FilipBauerHillebrandetal.2014, author = {Filip, Joanna and Bauer, Barbara and Hillebrand, Helmut and Beniermann, Anna and Gaedke, Ursula and Moorthi, Stefanie D.}, title = {Multitrophic diversity effects depend on consumer specialization and species-specific growth and grazing rates}, series = {Oikos}, volume = {123}, journal = {Oikos}, number = {8}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0030-1299}, doi = {10.1111/oik.01219}, pages = {912 -- 922}, year = {2014}, abstract = {Ecosystem functioning is affected by horizontal (within trophic groups) and vertical (across trophic levels) biodiversity. Theory predicts that the effects of vertical biodiversity depend on consumer specialization. In a microcosm experiment, we investigated ciliate consumer diversity and specialization effects on algal prey biovolume, evenness and composition, and on ciliate biovolume production. The experimental data was complemented by a process-based model further analyzing the ecological mechanisms behind the observed diversity effects. Overall, increasing consumer diversity had no significant effect on prey biovolume or evenness. However, consumer specialization affected the prey community. Specialist consumers showed a stronger negative impact on prey biovolume and evenness than generalists. The model confirmed that this pattern was mainly driven by a single specialist with a high per capita grazing rate, consuming the two most productive prey species. When these were suppressed, the prey assemblage became dominated by a less productive species, consequently decreasing prey biovolume and evenness. Consumer diversity increased consumer biovolume, which was stronger for generalists than for specialists and highest in mixed combinations, indicating that consumer functional diversity, i.e. more diverse feeding strategies, increased resource use efficiency. Overall, our results indicate that consumer diversity effects on prey and consumers strongly depend on species-specific growth and grazing rates, which may be at least equally important as consumer specialization in driving consumer diversity effects across trophic levels.}, language = {en} } @article{MeyerEbelingEisenhaueretal.2016, author = {Meyer, Sebastian T. and Ebeling, Anne and Eisenhauer, Nico and Hertzog, Lionel and Hillebrand, Helmut and Milcu, Alexandru and Pompe, Sven and Abbas, Maike and Bessler, Holger and Buchmann, Nina and De Luca, Enrica and Engels, Christof and Fischer, Markus and Gleixner, Gerd and Hudewenz, Anika and Klein, Alexandra-Maria and de Kroon, Hans and Leimer, Sophia and Loranger, Hannah and Mommer, Liesje and Oelmann, Yvonne and Ravenek, Janneke M. and Roscher, Christiane and Rottstock, Tanja and Scherber, Christoph and Scherer-Lorenzen, Michael and Scheu, Stefan and Schmid, Bernhard and Schulze, Ernst-Detlef and Staudler, Andrea and Strecker, Tanja and Temperton, Vicky and Tscharntke, Teja and Vogel, Anja and Voigt, Winfried and Weigelt, Alexandra and Wilcke, Wolfgang and Weisser, Wolfgang W.}, title = {Effects of biodiversity strengthen over time as ecosystem functioning declines at low and increases at high biodiversity}, series = {Ecosphere : the magazine of the International Ecology University}, volume = {7}, journal = {Ecosphere : the magazine of the International Ecology University}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {2150-8925}, doi = {10.1002/ecs2.1619}, pages = {14}, year = {2016}, language = {en} } @article{MeyerPtacnikHillebrandetal.2017, author = {Meyer, Sebastian Tobias and Ptacnik, Robert and Hillebrand, Helmut and Bessler, Holger and Buchmann, Nina and Ebeling, Anne and Eisenhauer, Nico and Engels, Christof and Fischer, Markus and Halle, Stefan and Klein, Alexandra-Maria and Oelmann, Yvonne and Roscher, Christiane and Rottstock, Tanja and Scherber, Christoph and Scheu, Stefan and Schmid, Bernhard and Schulze, Ernst-Detlef and Temperton, Vicky M. and Tscharntke, Teja and Voigt, Winfried and Weigelt, Alexandra and Wilcke, Wolfgang and Weisser, Wolfgang W.}, title = {Biodiversity-multifunctionality relationships depend on identity and number of measured functions}, series = {Nature Ecology \& Evolution}, volume = {2}, journal = {Nature Ecology \& Evolution}, number = {1}, publisher = {Nature Publ. Group}, address = {London}, issn = {2397-334X}, doi = {10.1038/s41559-017-0391-4}, pages = {44 -- 49}, year = {2017}, abstract = {Biodiversity ensures ecosystem functioning and provisioning of ecosystem services, but it remains unclear how biodiversity-ecosystem multifunctionality relationships depend on the identity and number of functions considered. Here, we demonstrate that ecosystem multifunctionality, based on 82 indicator variables of ecosystem functions in a grassland biodiversity experiment, increases strongly with increasing biodiversity. Analysing subsets of functions showed that the effects of biodiversity on multifunctionality were stronger when more functions were included and that the strength of the biodiversity effects depended on the identity of the functions included. Limits to multifunctionality arose from negative correlations among functions and functions that were not correlated with biodiversity. Our findings underline that the management of ecosystems for the protection of biodiversity cannot be replaced by managing for particular ecosystem functions or services and emphasize the need for specific management to protect biodiversity. More plant species from the experimental pool of 60 species contributed to functioning when more functions were considered. An individual contribution to multifunctionality could be demonstrated for only a fraction of the species.}, language = {en} }