1. Predictive power of food web models based on body size decreases with trophic complexity.
- Author
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Jonsson, Tomas, Kaartinen, Riikka, Jonsson, Mattias, and Bommarco, Riccardo
- Subjects
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FOOD chains , *BIOLOGICAL productivity , *BODY size , *PREDATION , *MICROCOSM & macrocosm , *ANIMAL morphology - Abstract
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 ofIS from models with allometrically scaled parameters. Body size was a strong predictor ofIS in simple modules (r 2 = 0.92), but with increasing complexity the predictive power decreased, with modelIS 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 predictingIS is related to the size of behaviour‐mediated effects. Our findings encourage development of dynamical food web models explicitly including and exploring indirect mechanisms. [ABSTRACT FROM AUTHOR]- Published
- 2018
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