Abstract

Food web models parameterised using body size show promise to predict trophic interaction strengths (IS) and abundance dynamics. However, this remains to be rigorously tested in food webs beyond simple trophic modules, where indirect and intraguild interactions could be important and driven by traits other than body size. We systematically varied predator body size, guild composition and richness in microcosm insect webs and compared experimental outcomes with predictions of IS from models with allometrically scaled parameters. Body size was a strong predictor of IS in simple modules (r(2)=0.92), but with increasing complexity the predictive power decreased, with model IS being consistently overestimated. We quantify the strength of observed trophic interaction modifications, partition this into density-mediated vs. behaviour-mediated indirect effects and show that model shortcomings in predicting IS is related to the size of behaviour-mediated effects. Our findings encourage development of dynamical food web models explicitly including and exploring indirect mechanisms.

Keywords

Allometric trophic network model; body size ratio; indirect effects; indirect interactions; interaction strength; non-consumptive effect; predator-prey interaction; species' traits; trophic interaction modification

Published in

Ecology Letters
2018, Volume: 21, number: 5, pages: 702-712
Publisher: WILEY

SLU Authors

• Jonsson, Tomas

  • Department of Ecology, Swedish University of Agricultural Sciences
    
  • University of Skövde

• Kaartinen, Riikka

  • Department of Ecology, Swedish University of Agricultural Sciences
    

• Jonsson, Mattias

  • Department of Ecology, Swedish University of Agricultural Sciences
    

• Bommarco, Riccardo

  • Department of Ecology, Swedish University of Agricultural Sciences
    

Sustainable Development Goals

SDG15 Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss


UKÄ Subject classification

Ecology


Publication identifier

DOI: https://doi.org/10.1111/ele.12938

Permanent link to this page (URI)

https://res.slu.se/id/publ/95034