Special Seminar - Michael Raatz: How consumers cope with nutritional (co-)limitation in variable environments

  • Date: Jul 9, 2018
  • Time: 02:00 PM - 03:00 PM (Local Time Germany)
  • Speaker: Michael Raatz from the University of Potsdam
  • For more information on Michael Raatz, please check: https://www.uni-potsdam.de/de/ibb-theoaqua/group-members/michael-raatz.html
  • Location: MPI Plön
  • Room: Lecture hall
  • Host: Arne Traulsen


Consumer-resource interactions are fundamental to many ecosystem functions and services. The various
resources that simultaneously co-limit consumer growth are often heterogeneously distributed in space or
fluctuate within a patch in time. This spatio-temporal heterogeneity translates to a perceived temporal variability
of resource abundance for the consumer, which is shaped by landscape characteristics, movement behavior
and environmental factors. The consequences of such a variability and changes to it, e.g. by environmental
change, remain unclear. Here, we combine modelling and experiments to understand how consumer growth,
at the organismal level, is affected by the nutritional variability of the environment. Thereby, we decompose
this variability into its four most prominent components (amplitude, frequency, phase and covariance). Besides
general agreement of model predictions and experimental results we find that all these factors strongly affect
somatic growth of consumers. Employing a Dynamic Energy Budget model we can decipher our experimental
data of Daphnia growth in fluctuating, co-limiting conditions and show that consumer physiology may adapt
to resource variance and covariance by mechanisms such as resource storage or acclimation of resource assimilation.
Going beyond that, we predict that two of the major anthropogenic stressors which increase landscape
homogeneity, i.e. the reduction of between-patch differences and the enlargement of single patches, might
affect local consumer performance in opposite directions.

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