Ecosystem function in predator-prey food webs-confronting dynamic models with empirical data.

Area of Science:

• Ecology
• Food web dynamics
• Ecological modeling

Background:

• Ecosystem functions rely on species interactions across trophic levels.
• Understanding multitrophic communities is limited by trade-offs between mechanistic insight and ecological realism.
• Advances in molecular tools and trait-based approaches enable more realistic food web models.

Purpose of the Study:

• To test an allometric food web model's ability to replicate field abundance data.
• To gain mechanistic insight into the function of predation in controlling herbivore populations.
• To explore drivers of population dynamics using dynamic food web models.

Main Methods:

• Utilized a dynamic food web model with field-observed interactions and abundances.
• Applied inverse problem methods for model fit optimization and parameterization.
• Tested the model's ability to reproduce aphid (Rhopalosiphum padi) abundance data from ten Swedish barley fields.

Main Results:

• The model successfully explained over 70% of aphid abundance variation in five of ten fields.
• Results support the hypothesis that body size is a key determinant of predation in arthropod communities.
• Model analysis identified community abundance and trait composition as drivers of ecosystem function.

Conclusions:

• Dynamic food web models confronted with field data are valuable for evaluating ecological theory and understanding ecosystem function.
• Body size is an important, but not the sole, determinant of predation.
• Refining trait-based parameterization in food web models is crucial for advancing ecosystem research.