Predictive power of food web models based on body size decreases with trophic complexity

Jonsson, TomasSwedish University of Agricultural Sciences,Sveriges lantbruksuniversitet,Högskolan i Skövde,Institutionen för biovetenskap,Forskningscentrum för Systembiologi,Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden,Ekologisk modellering, Ecological Modelling Group,Institutionen för ekologi,University of Skövde (författare)

© 2018 John Wiley & Sons Ltd/CNRS
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.

Kaartinen, RiikkaSwedish University of Agricultural Sciences,Sveriges lantbruksuniversitet,Institutionen för ekologi,Department of Ecology,Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden(Swepub:slu)92889 (författare)
Jonsson, MattiasSwedish University of Agricultural Sciences,Sveriges lantbruksuniversitet,Institutionen för ekologi,Department of Ecology,Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden(Swepub:slu)46968 (författare)
Bommarco, RiccardoSwedish University of Agricultural Sciences,Sveriges lantbruksuniversitet,Institutionen för ekologi,Department of Ecology,Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden(Swepub:slu)50048 (författare)
Högskolan i SkövdeInstitutionen för biovetenskap (creator_code:org_t)
Sveriges lantbruksuniversitet

Ingår i:Ecology Letters: Wiley-Blackwell Publishing Inc.21:5, s. 702-7121461-023X1461-0248

Av författaren/redakt...: Jonsson, Tomas; Kaartinen, Riikk ...; Jonsson, Mattias; Bommarco, Riccar ...

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