Theoretical Ecology

, Volume 7, Issue 1, pp 23–33

Size-based predictions of food web patterns

  • Lai Zhang
  • Martin Hartvig
  • Kim Knudsen
  • Ken H. Andersen
Original Paper

DOI: 10.1007/s12080-013-0193-5

Cite this article as:
Zhang, L., Hartvig, M., Knudsen, K. et al. Theor Ecol (2014) 7: 23. doi:10.1007/s12080-013-0193-5

Abstract

We employ size-based theoretical arguments to derive simple analytic predictions of ecological patterns and properties of natural communities: size-spectrum exponent, maximum trophic level, and susceptibility to invasive species. The predictions are brought about by assuming that an infinite number of species are continuously distributed on a size–trait axis. It is, however, an open question whether such predictions are valid for a food web with a finite number of species embedded in a network structure. We address this question by comparing the size-based predictions to results from dynamic food web simulations with varying species richness. To this end, we develop a new size- and trait-based food web model that can be simplified into an analytically solvable size-based model. We confirm existing solutions for the size distribution and derive novel predictions for maximum trophic level and invasion resistance. Our results show that the predicted size-spectrum exponent is borne out in the simulated food webs even with few species, albeit with a systematic bias. The predicted maximum trophic level turns out to be an upper limit since simulated food webs may have a lower number of trophic levels, especially for low species richness, due to structural constraints. The size-based model possesses an evolutionary stable state and is therefore un-invadable. In contrast, the food web simulations show that all communities, irrespective of number of species, are equally open to invasions. We use these results to discuss the validity of size-based predictions in the light of the structural constraints imposed by food webs.

Keywords

Biodiversity Food web assembly Individual size distribution Size spectrum Traits Maximum trophic level 

Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  • Lai Zhang
    • 1
  • Martin Hartvig
    • 2
    • 3
  • Kim Knudsen
    • 1
  • Ken H. Andersen
    • 4
  1. 1.Department of Applied Mathematics and Computer ScienceTechnical University of DenmarkLyngbyDenmark
  2. 2.National Institute of Aquatic ResourcesTechnical University of DenmarkCharlottenlundDenmark
  3. 3.Center for Macroecology, Evolution and ClimateUniversity of CopenhagenCopenhagen ØDenmark
  4. 4.Center for Ocean Life, National Institute of Aquatic ResourcesTechnical University of DenmarkCharlottenlundDenmark
  5. 5.Department of Mathematics and Mathematical StatisticsUmeå UniversityUmeåSweden

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