@misc{SperfeldRaubenheimerWacker2016,
  author    = {Sperfeld, Erik and Raubenheimer, David and Wacker, Alexander},
  title     = {Bridging factorial and gradient concepts of resource co-limitation: towards a general framework applied to consumers},
  series = {Ecology letters},
  volume    = {19},
  journal   = {Ecology letters},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {1461-023X},
  doi       = {10.1111/ele.12554},
  pages     = {201 -- 215},
  year      = {2016},
  abstract  = {Organism growth can be limited either by a single resource or by multiple resources simultaneously (co-limitation). Efforts to characterise co-limitation have generated two influential approaches. One approach uses limitation scenarios of factorial growth assays to distinguish specific types of co-limitation; the other uses growth responses spanned over a continuous, multi-dimensional resource space to characterise different types of response surfaces. Both approaches have been useful in investigating particular aspects of co-limitation, but a synthesis is needed to stimulate development of this recent research area. We address this gap by integrating the two approaches, thereby presenting a more general framework of co-limitation. We found that various factorial (co-)limitation scenarios can emerge in different response surface types based on continuous availabilities of essential or substitutable resources. We tested our conceptual co-limitation framework on data sets of published and unpublished studies examining the limitation of two herbivorous consumers in a two-dimensional resource space. The experimental data corroborate the predictions, suggesting a general applicability of our co-limitation framework to generalist consumers and potentially also to other organisms. The presented framework might give insight into mechanisms that underlie co-limitation responses and thus can be a seminal starting point for evaluating co-limitation patterns in experiments and nature.},
  language  = {en}
}
@article{SperfeldMartinCreuzburgWacker2012,
  author    = {Sperfeld, Erik and Martin-Creuzburg, Dominik and Wacker, Alexander},
  title     = {Multiple resource limitation theory applied to herbivorous consumers Liebig's minimum rule vs. interactive co-limitation},
  series = {Ecology letters},
  volume    = {15},
  journal   = {Ecology letters},
  number    = {2},
  publisher = {Wiley-Blackwell},
  address   = {Malden},
  issn      = {1461-023X},
  doi       = {10.1111/j.1461-0248.2011.01719.x},
  pages     = {142 -- 150},
  year      = {2012},
  abstract  = {There is growing consensus that the growth of herbivorous consumers is frequently limited by more than one nutrient simultaneously. This understanding, however, is based primarily on theoretical considerations and the applicability of existing concepts of co-limitation has rarely been tested experimentally. Here, we assessed the suitability of two contrasting concepts of resource limitation, i.e. Liebigs minimum rule and the multiple limitation hypothesis, to describe nutrient-dependent growth responses of a freshwater herbivore (Daphnia magna) in a system with two potentially limiting nutrients (cholesterol and eicosapentaenoic acid). The results indicated that these essential nutrients interact, and do not strictly follow Liebigs minimum rule, which consistently overestimates growth at co-limiting conditions and thus is not applicable to describe multiple nutrient limitation of herbivorous consumers. We infer that the outcome of resource-based modelling approaches assessing herbivore population dynamics strongly depends on the applied concept of co-limitation.},
  language  = {en}
}